PROGRAM
OF
The 114thMeetingof the AcousticalSocietyof America
Hyatt RegencyHotel © Miami, Florida ß 16-20 November1987
MONDAYEVENING,'I6 NOVEMBER1987
UM AUDITORIUM,
Tutorial
7:00 TO 9:00 P.M.
Lecture
Introductionto Musical Acoustics.ThomasD. Rossirig(Departmentof Physics,Northern Illinois
University,DeKalb, IL 60115)
Musicalacoustics
isa broadinterdisciplinary
fieldthatdealswiththeproduction,
transmission,
andperception
ofmusical
sound.
It overlaps
several
otherbranches
ofacoustics,
suchasphysical
acoustics,
shock
and
vibration,
architectural
acoustics,
psychoacoustics,
speech
communication,
andelectroacoustics.
In thisintroductorytutorial,considerable
attention
willbepaidto howsoundisgenerated
byvariousmusicalinstruments.
In percussion
instruments
andin certainstringinstruments,
theplayersupplies
energy
bystriking
orplucking
theprimaryoscillator
(string,bar,membrane,
orplate),whichin turntransmits
energy
tootherpartsofthe
instrument.Wind instruments,
on theotherhand,dependuponnonlinearfeedbackfrom theair columnto the
inputcontrolvalveinordertogenerate
sustained
oscillations.
Similarfeedback
exists
inabowed
stringinstrument,andto a lesserextentin the singingvoice.Time will allowonlya briefdiscussion
of howthe soundis
transmitted
fromthesource
tothelistener
viatheauditorium
orbyelectroacoustic
means,
suchasrecording,
reproducing,
andbroadcasting
systems.
Finally,certainaspects
of theperception
of musicalsound(suchas
loudness,
pitch,andtimbre) will beconsidered.
TUESDAY MORNING,
17 NOVEMBER
1987
BOUGAINVILLEA
ROOM, 8:30 TO 11:05 A.M.
SessionA. EngineeringAcousticsI: StructureInteractionand TransducerArrays
AnthonyJ. Rudgcrs,Chairman
UnderwaterSoundReferenceDetachment,Naval ResearchLaboratory,P.O. Box 8337, Orlando,Florida 32856
Chairman's
Introductions8:30
ContributedPapers
8:35
AI. Application,ofa variationalprinciplefor fluid-structureinteraction
to theanalysisof the response
of an elasticdiskin a finitebaffle.Jerry
H. Ginsbergand Pei-Tai Chen (Schoolof MechanicalEngineering,
GeorgiaInstituteof Technology,Atlanta, GA 30332)
pressure
on the baffleradiusis examined;resultsin the limit of an infinite
baffleareshownto agreewellwitha prioranalysis
by AlperandIVlagrab
[J. Acoust.Soc.Am. 48, 681-690 (1970) ]. [Work supportedby the Officeof Naval Research,Code 1132-F.]
A variationalprinciplederivedfrom the Kirchhoff-Helmholtzinte-
graltheorem
waspreviously
employed
topredictthesurface
pressure
and
vibrational
response
ofanunbaffled
elasticdiskto harmonicexcitation[J.
H. Ginsbergand A.D. Pierce,J. Aeoust.Soc.Am. Suppl.I 79, S35
(1986)]. Here,theanalysis
isextended
todescribe
a finiterigidbaffleby
usingassumed
modefunctions
for the pressure
distribution
alongthe
vibratingandrigidsurfaces.
Versionsusingvariousanalyticalfunctions,
aswell asfiniteelementmodes,are developedand examinedfor convergence,numericalaccuracy,and efficiency.Dependenceof the surface
$1
J. Acoust.$oc.Am.Suppl.1, Vol.82, Fall1987
8:50
A2. Modal contributions
of a finiteplateto powerspectra.SungH. Ko
(Naval Underwater SystemsCenter, New London, CT 06320)
The purposeof thiswork is to comparethe modalcontribution
of a
finiteelasticplateto thepowerspectrumand the flexuralwavecontributionof aninfiniteelasticplateto thepowerspectrum.Flexuralwaw:sin an
infiniteplatesubmerged
in a fluidproducepressure
wavesin thefluidthat
114thMeeting:Acoustical
Societyof America
$1
travelparallelto theplateanddecayawayfromtheplatesurface
in the
cylindrical
NFCAshavebeendeveloped.
Thispaperdescribes
a spherical
fluid.Thesewavesmaybecalledevanescent
wavesandarestrongest
in a
regionneartheplatewheretheymayrepresent
noise.Whena rectangular
platesubmerged
in a fluidisexcited,thevibratingplategenerates
pressure
wavesthat decayawayfrom theplatesurfacein thefluidandan acoustic
wavethatradiatesintothefluid.The analyticalmodelconsidered
hereisa
two-sided
fluid-loaded
rectangular
platesimplysupported
at itsboundariesandexcitedby a forcingfunctionononesideof theplate.Theoretical
analyses
arediscussed
andthewavenumber-dependent
transferfunctions
thatareusedforcalculating
powerspectraarepresented.
[Work supported by NUSC. ]
NFCA fordetermining
thefull three-dimensional
radiationpatternof an
enclosed
transducer.
In theory,theNFCA consists
of a largenumberof
discrete
hydrophone
elements
arranged
overa spherical
surface
inNequispaced
constant
latitudebands.In practice,thearraycanbesynthesized
by useof a singlesemicircular
arccontaining
relativelyfewelements
and
9:05
byeitherrotation
ofthetransducer
orrevolution
ofthearcabout
thepolar
axis.Individualhydrophone
sensitivities
(bothamplitude
andphase)are
selected
sothat theNFCA servesasa plane-wave
filterfor acousticradiationfrominsidethesphere.
Therelativesensitivities,
calledshading
coefficients,arecomputed
usingtheNFCA reciprocityprincipleanda leastsquaresprocedure.Only a few setsof N/2 shadingcoefficients
are
requiredfor full three-dimensional
operation
of theNFCA overa frequencyrangeof threeoctav•sor more.Designcriteriaarediscussed
and
samplenumericalresultsare presented.
A3. Impulseresponses
andradiationimpedaneas
of cylindricalvibrators
usingwave-vector-time
domain(k-t) methods.
PeterR. Stepanishcn
and
D. D. Ebenezer(Departmentof Ocean Engineering,Universityof
RhodeIsland,Kingston,R! 02881-0814)
A wave-vector-timedomain (k-t) methodis presentedto evaluate
the harmonicandtime-dependent
loadingon a cylindricalshellthat is
vibratingwitha specified
spatialandtime-dependent
velocity.The method is basedon utilizinga specified
time-dependent
modalexpansion
for
the radialvelocityof the vibrator.The acousticloadingon the vibratoris
alsoexpressed
asa modalexpansion
in whicheachcoefficient
isa summationofconvolution
integrals
of themodalvelocitycoefficients
withmode-
dependent
radiationimpulse
responses.
In contrast
toanearlierwork[ D.
D. Ebenezerand Peter R. Stepanishen,
J. Acoust.Soc.Am. 81, 854-860
(1987) ], the radiation impulseresponses
are evaluatedusinga (k-t)
methodbasedona time-dependent
Green'sfunctionfor a baffledcylindrical vibrator.A comparison
of the newmethodwith the earliermethodis
presented
alongwithnumerical
results
forvarious
axialmodeshapes
and
circumferential
modenumbers.[Work supported
by ONR.]
9:20
A4. An array to produceconveerednormalvelocityandpressurefieldsfor
wavenumbercalibration and boundarylayer modification.H. C. Schau,
L. Dwight Luker, and S. Petrie (Naval Research Laboratory,
Underwater Sound Reference Detachment, P.O. Box 8337, Orlando, FL
32856-8337)
9:50
A6. Designof an experimentto measurethe acousticmutualimpedances
of a resonant,close-packedsonar array. Stephen C. Thompson
(Acousticsand SensorSystems,OceanSystemsDivision,Gould, Inc.,
18901 Euclid Avenue, Cleveland, OH 44117)
Knowledgeof the acousticmutualimpedancecoefficients
for a sonar
array is necessary
to achievean accurateanalyticaldescriptionof the
performanceof the array. In the early stagesof a design,analyticalapproximations,e.g., of an array in an infiniterigid planebaffle,provide
adequate
estimates.
Whenprototypehardwareisavailable,it maybeappropriateto deriverefinedestimatesof the impedancecoefficients.
This
allowsmoreaccuratepredictionof theeffectsof designchanges
onperformance,and alsoprovidesan analyticalbaselinefor a designthat is enteringproduction.The measurement
of themutualimpedance
coefficients
in
a resonant,close-packed
array is difficult.The only previouslyreported
attempt[StephenC. Thompson,J. Acoust.Soc.Am. Suppl.1 68, S34
(1980] achievedinconclusiveresults,due to inaccurateestimatesof the
elementelectromechanical
transfermatricesand strongelementinteractionsthat occurin the vicinityof the elementresonance
frequency.These
measurements
arcbeingrepeated,with greatercaregivento thepreviously noteddeficiencies.
The experimentwill be described,
concludingwith
therequirements
placedon thespecialtransducer
elementsthat werenecessaryfor the measurement.
The designof thesetransducerelementsv½ill
be describedin a companionpaper in this session[M.P. Johnson,J.
Acoust.Soc.Am. Suppl. 1 82, S2 (1987)].
A transmittingarray is describedthat is capableof producingspecifiednormalvelocitydistributions
at thesurfaceof thearray.Suchan array
is usefulin the productionof convected
normalvelocitiesand pressure
fieldsthat may emulateturbulentboundarylayer pressurefields.The
pressure
fieldsareconvective
in nature,movingparalleltotheplaneofthe
arraywitha phasevelocitythat isslow,i.e.,lessthanthespeedof soundin
themedium.A slowphasevelocitycorresponds
to a spatialwavenumber
k thatisgreaterthanthecorresponding
acoustic
wavenumber
inthemedium.Applications
includeboundarylayermodification,
testingof sensors
in controlled TBL flows, and wavenumbercalibration of sensors.Results
arepresented
for severalprototypearraysinvolvingdifferentconstruction
methodologies.
Shadingschemes
for theproductionof uniformconveered
pressure
fieldsare discussed
relativeto the physicallimitationsof the
deviceand electronics.Measuredpressurefieldsand phasevelocityare
contrastedwith thosepredictedtheoretically.Plansfor producinglarger
and morecomplexarraysare discussed
relativeto currentprototyperesults.[Work partiallysupportedby ONT.]
9:35
AS. Sphericalnearfieldcalibrationarray for three-dimensionaiscanning.
A. L. Van Buren (Underwater Sound Reference Detachment, Naval
ResearchLaboratory,P. O. Box 8337,Orlando, FL 32856-8337)
Nearfieldcalibrationarrays (NFCAs) are usedto determinethe farfield acousticradiation from a transducerby measurementsmade in the
nearfield.The originalTrott NFCAs wereplanararrays.More recently,
S2
d. Acoust.Soc.Am.Suppl.1, Vol.82, Fall 1987
10:0S
A7. Design of a transducerelementfor an acousticmutual impedance
measurementexperiment. Michael P. Johnson (Acoustics and Sensor
Systems,Ocean SystemsDivision, Gould, Inc., 18901 Euclid Avenue,
Cleveland, OH 44 117)
A companionpaperin this sessionhas describedan experimentto
measurethe acousticmutual impedancesin a resonant,close-packedso-
nar array [S.C. Thompson,J. Acoust.Soc.Am. Suppl.182, S2 (1987) ].
This experimentrequiresthe useof specialmeasurement
transducers
in
placeof theelements
in thearrayunderstudy.Therewereseveralspecial
requirements
for thesetransducers:
( 1) highmechanical
inputimpedance
at the elementradiatingface; (2) accurateknowledgeof the transducer
electromechanical
impedancematrix;and (3) radiatingfacedimensions
that are identicalto thoseof the clementsof the array understudy.The
firstrequirementreducesthe effectsof interelementcouplingand,consequently,reducesthe sensitivityin the calculationsto errorsin the measurement.The secondacknowledges
that the electromechanical
impedance matrices of the transducer elements are needed in the calculation.
The third requirementprovidesa measurementarray with the samemutual impedancecoefficients
asthe array understudy.A prototypetransducerelementthat seemsto meettheserequirementsis a doublyresonant
pistonelement.The elementisdesigned
sothattheoperatingbandof the
array understudyfallsbetweenthe two resonantfrequencies
of the measurementtransducer.
The designandperformance
of thiselementwill be
described.
114thMeeting:AcousticalSocietyof America
$2
10:20
AS.A diffuse
fieldsonartankformeasurement
ofprojector
sound
power
levelanddireetivity
index.David Lubman(D. Lubman& Associates,
14301MiddletownLane,Westminster,
CA 92683)
Though
widelyusedinairacoustics,
thediffuse
fieldtechnique
hasnot
beenextensively
usedin underwater
acoustics.
Thispaperdescribes
a
small
(2ma)diffuse
fieldsonar
tankfacility
intended
forproduction
testingofthesteady-state
sound-power
levelanddirectivity
indexof widebandsonarprojectors.
Whenevaluated
bystandards
usedin air acoustics
toensure
adequate
diffuse
fieldmeasurement
accuracy,
thiscompact
and
inexpensive
facilityappears
tobequalified
forthedetermination
of bandaveraged
sound.-power
levelovera frequency
rangeexceeding
fiveoctaves
thefactorsgoverning
therealizations
of practicalechosonde
patterns;
whicharesuitable
for turbulence
detection
of atmospheric
irregularities,
suchasthermalstructures,
dynamics,andturbulentvelocityfielctsat the
loweratmosphere;
andfromwhichphysically
realizablesourcefieldsex-
thesized.
Last,a comparative
analysis
showsthattheapproximate
pat-
hibiting
no
abrupt
discon
acros
the
ante
ape
ca
be
sy
ternsgenerated
fromthe synthesized
sourcedistributions
manifestgood
mean-square
fitsto the idealizedacoustic
beamsoriginallyspecified
almostall overthe entirevisiblerangesof the patternsprescribed.[Work
supported
by LagosStateUniversity,BadagryExpressway,
Ojo, Lagos,
througha VisitingProfessorial
Appointment.
]
(fromabout4 lo 160kHz). Whencompared
witha free-field
measurementfacility,
thepractical
advantages
ofthisapproach
include
largesaw
ingsin costandspace.
Longtransducer
risetimesarepermitted
since
measurements
aresteadystate.Moreover,theimplicitspatialintegration
ofradiation
patterns
makes
results
ofdiffuse
fieldtesting
moreappropriatethanfree-field
testingfor someapplications.
10:50
AI0. Development
of higher-orderZernike polynomials
employedin the
analysis
of aeonstie
sensing
antennas.
S. AdeniyiAdekola(LagosState
University(FETES), BadagryExpressway,
Ojo,Lagos,Nigeria)
Zernikecirclepolynomials
havebeenfoundtobeinvaluableanalytical
toolsforinvestigating
thecharacteristics
of acoustic
sensing
antennasIS.
A. Adekola,Acustica47, 11½-131( 1981) ]. New analyticalresultsob-
10:35
A9. Practicalacousticbeamsandsynthesized
sourcefieldsfor turbulence
detectionat the lower atmosphere.
S. Adeniyi Adekola (LagosState
University(FETES), BadagryExpressway,
Ojo, Lagos,Nigeria)
tainedfromaninvestigation
ofthegeneralized
R • ( r ) Zernikecirclepolynomials,
summarized
in theabove-mentioned
reference,
areof higherdegreesof accuracythan thosepresentlyavailablein the literature.Indeed,
tiesat theboresight
regionoftheapertureandareconsiderably
attenuated
thesepolynomials
aregenerated
to 30øand29øof freedomdescribing
the
even-andodd-numbered
modes,respectively;
and the fieldradiatedby
the acousticsensingantenna,whichis then expressed
in termsof the
polynomials,
isevaluated
throug.h
directroutineintegration.
Someof the
newanalyticalresultsevaluatedand numericallycomputedare heredisplayedin graphicalformsfor completeness.
Also,illustrative
examples
givenshownotonlyhowtheZernikepolynomials
canbeemployed
in the
interpretations
of theradiationcharacteristics
of theacousticechosoundingsystems,
but alsohowusecanbemadeof thepolynomials
to describe
towards the rim of the antenna cuff. It is also shown that if the beamwidth
significantlytaperedsourcedistributionsessentialin successfulacoustic
ofthepatternprescribed
isextremelynarrow,thenthesourcedistribution
synthesized
fromit tendsto produce
anundesirable
strongfieldor singularity at therim of theantennacuff.The paperthenfocuses
attentionon
remotesensing
of theloweratmosphere.
[ Work supportedbyLagosState
Computersimulations
of newanalyticalresultsthat are important
extensions
of an earlierwork IS. A. Adekola,J. Acoust.Soc.Am. 76, 345368 (1984) ] are herepresented
for the echosonde
(acousticechosounding) system.It isshownthatthesourcedistributions
synthesized
fromthe
prcassigned
dinretirepressurefieldsarc not only confinedwithin finite
antennaapertureregions,butarealsocharacterized
by maximumintensi-
TUESDAY' MORNING,
17 NOVEMBER
1987
UNIVERSITY
University,
BadagryExpressway,
Ojo,Lagos,througha VisitingProfessorialAppointment.]
LECTURE
HALL, 8:30 A.M. TO 12:00 NOON
Session
B. Psychological
andPhysiological
Acoustics
I: Hearing-Impaired
Speech
andAuditoryPerception
JosephW. Hall, III, Chairman
Division
of Otology,
University
ofNorthCarolina,
610Burnett-Womack
Building,
22911,Chapel
Hill,
North Carolina
27514
ContributedPapers
8:30
B1. The effect of varying the amplitude-frequency
responseon the
maskedSRT for sentences
in hearing-impairedlisteners.JanctteN. van
Dijkhuizen, Joost M. Festcn, and Reinlet Plomp (Experimental
Audiology,ENT Department,Free UniversityHospital,Amsterdam,
withinlimits,unaffected
bydynamic
variations
in theamplitude-fi'equencyresponse
ofthehearingaid.Fornormal-hearing
listeners,
vanDijkhui-
incomingsignal,.
mayoptimallydeliverspeech
to an impairedcar.Sucha
zen et al. [J. Acoust.Soc. Am. 81, 465-496 (1987)] found that the
maskedSRT for sentences
is remarkablyresistantto dynamicvariations
in the slopeof the amplitude-frequency
response
whenit shapedboth
speechand noise.In thisexperiment,we studiedcorresponding
conditionsfor hearing-impaired
listeners.
Again,the amplitude-frequency
response
shapedbothspeech
andnoiseandthusleft speech-to-noise
ratios
untouched.
The resultsobtainedso far alsoindicatethat, for hearingimpairedlisteners,
dynamicvariationsof the amplitude-frequency
re-
systemrequiresthat the speech-reception
threshold(SRT) in noiseis,
sponsedo not affectthe SRT.
The Netherlands)
A multichannelgain-controlhearingaid, in which the frequency-dependentamplificationis adaptedautomaticallyto the fluctuationsof the
S3
J. Acoust.
Soc.Am.Suppl.1,Vol.82, Fall1987
114thMeeting:
Acoustical
Societyof America
S3
8:45
B2. Explorations
on the differencein $RT betweena stationarynoise
masker and an interfering speaker.Joost M. Festen (Experimental
Audiology,
ENT Department,
FreeUniversity
Hospital,Amsterdam,
The Netherlands)
For moderatehearingimpairment,the speech-reception
threshold
(SRT) for sentences
in stationarynoiseisroughlyup to 5 dB higherthan
correlations
werefoundamongthepsychoacoustic
variables,
whichalso
predicted
PFFIN score.
Correlations
between
hearing
levels
andPFFIN
remained
significant
afterpartiallugage,noiseexposure,
upwardspread
ofmasking
at2 kHz,andeducational
andlinguistic
measures.
Systematicallytruncatingthe HL distribution
showedthat thiscorrelation
lies
mostlyin the 15-25dBHL rangeandimplicates
low-aswellashighfrequency
hearing.
Thusthe17%oftheadultpopulation
between
15and
25 dB HL (0.5-4.0 kHz) shouldbe consideredmarginal,both clinically
fornormalhearing.However,a fluctuating
interfacing
soundseems
more
typicalfor everydaylisteningconditions
thanstationary
noise.For a
groupof younghearing-impaired
listeners,
thedifference
in SRT with
normal-hearing
listenersincreased
from 2.7 dB for stationarynoiseto 7
dB for 100%sinusoidally
intensity-modulated
noise,andevento 10.5dB
forinterfering
speech.
In thisexperiment,
theinterfering
speech
wasthe
time-reversed
voiceof the samespeakeras the signal,whichmay have
introducedan extradifficulty.In a subsequent
experiment,the SRT for
sentences
fromtwo speakers
(onemaleandonefemale)wasmeasured
witha varietyof fluctuating
maskers
covering
therangefromstationary
noisetointerfering
speech.
Thetwovoices
weremutuallyusedasmusket,
givinga meaningful
interference.
Meaningless
interference
wasobtained
bytimereversal
oftheinterfering
speech
orbymodulating
noisewiththe
envelope
of speech.
Two typesof modulation
wereused:onebroadband
andonein whichhigh-and low-frequency
noise(separationfrequency
1000Hz) wasmodulatedwith the high-andlow-frequency
envelope
of
speech,respectively.
9:00
B3. Reducedauditory discriminationand compression
in hearingaids.
Wouter A. Dreschler(AcademicMedical Center,Clinical Audiology,
University of Amsterdam, Amsterdam,The Netherlands)
andexperimentally.
Scientifically,
if notpragmatically,
a "lowfence"at
15dB HL isjustified.
9:30
B$. EvaluatingtheArticulationIndexfor auditory-visualinput.Ken W.
Grant (ResearchLaboratoryof Electronics,
Massachusetts
Instituteof
Technology,
Cambridge,
MA 02139)
The currentstandardfor calculatingthe ArticulationIndex (AI) ineludesa procedureto estimatethe effectiveAI whenhearingis combined
withspeechreading
[ANSI S3.5-1969(R 1978), "Methodsfor theCalculation of the Articulation Index" (American National StandardsInsti-
tute, New York, 1969)]. This procedureassumes
that the band-importancefunctionderivedfor auditorylisteningsituationsappliesequally
well to auditory-visualsituations.Recentstudieshaveshown,however,
that certain auditory signalsthat, by themselves,producenegligible
speechreceptionscores(e.g.,FO, speech-modulated
noise,etc.) canprovidesubstantial
benefitsto speechreading.
The existence
of suchsignals
suggests
that the band-importance
functionfor auditoryand auditoryvisualinputsmaybedifferent.In thepresentstudy,an attemptwasmade
to validate the auditory-visualcorrectionprocedureoutlined in the
ANSI-1969 standardby evaluatingauditory,visual,andauditory-visual
sentence
identification
performance
of normal-hearing
subjects
for both
Two specificapplicationsof single-channel
compression
are studied
separately:
whole-range
compression
asa compensation
for recruitment,
andcompression
limitingasan elegantmethodto limit excessive
output
wideband
speech
degraded
byadditivenoiseandbandpass-filtered
speech
presented
in quiet.The resultsobtainedfor auditorylisteningconditions
withanAI greaterthan0.03supporttheprocedure
outlinedin thecurrent
levels.In casesof compression
limiting, compression
provedto besuperior to peakclipping,especiallyfor the perceptionof consonants:
An averageimprovementin identificationscoresof 18% wasfound and lessrolloverfor the perceptionof finalconsonants
at highpresentation
levels.In
casesof whole-rangecompression,
a small, but significant,increasein
identificationscoreswasfoundfor settingswith the compression
kneepointat the lowestlevel.A detailedanalysisof the patternsof confusions
revealedclearqualitativedifferences
in the perceptionof phonemes
with
and withoutcompression.
Thesedifferences
canbebroughtinto relation
ANSI standard.[Work supportedby NIH.]
with an improvedperception
of temporalCues,like the prebursts/lent
9:45
B6. Frequencydiscriminationand consonant
recognitionin the hearing
impaired.Marleen T. Ochs (Departmentof CommunicationSciences
and Disorders,RadfordUniversity,Radford,VA 24142)
The frequency
difference
!imen(DL) for short-duration
second-formant transitions(F2) presentedaloneand in speechlike
environments
was examinedin normal hearingand hearing-impaired
subjects.Four
intervalof plosives,and with spectralchangesdueto the activationof the
compressioncircuit.
stimulusconditionswere included:F2 transitionalone;F2 transition in
thepresence
of all formants(full formant); full-formantstimulipreceded
by a hurstand followedby a vowel;andfull-formantstimuliprecededand
followedby a vowel.For the simpleststimuluscondition(F2 alone), all
9:15
hearing-impaired
subjects
hadDLs withinthe 95% confidence
interval
B4. Correlationsamongauditory functionsin the "normal" range.
around the mean of the normals. For all other conditions,however,the
Mark Haggard,GabrielleSaunders,and StuartGatehouse(MRC
Institute of Hearing Research, Nottingham NG7 2RD, United
hearingimpaireddemonstrated
extremeintersubject
variation.Some
hearing-impaired
subjects
couldnotdetecta formanttransition
of even
Kingdom)
800Hz, whereasotherscontinuedto performlike normalhearers.Consonantidentification
performance
wasalsoexaminedin CV andVCV envi-
To date,hearinglevelsandpyschoacoustic
measures
haveshownfactor structureandcorrelations
with speechperceptionin noiseamongthe
ronments. Consonants whose identification is believed to involve formant
hearingimpaired,
butnotamongclinically"normal"ears.A pseudofree-
transitionswere selectedfor study.In spiteof modifications
to the fre-
fieldsentence-in-noise
test(PFFIN) from a dummy-headrecording,sim-
quencydiscrimination
taskanduseof relevantsyllables,
relativelyweak
plifiedpsychoacoustic
tuningcurves,andtestsof linguistic
processing
correlations continue to be observed between F2 DL and consonant rec-
wereadministered
to 60 peoplewith hearingbetterthan20 dB HL (0.52.0 kHz); one-thirdhad complainedof auditorydifficulties.Significant
ognitionability, as well as betweenF2 DL and degreeof hearingloss.
[Work supportedby NIH. ]
10:00-10:15
Break
S4
J.Acoust.
Soc.Am.Suppl.
1,Vol.82,Fall1987
114thMeeting:
Acoustical
Society
ofAmerica
S4
10:15
11:00
B7. Lateral suppression
and auditory frequencyselectivity.Wouter
A. Dreschlerand A. gens Leeuw (AcademicMedical Center,Clinical
Audiology,Universityof Amsterdam,Amsterdam,The Netherlands)
B10. Sinusoidal modeling of speech: Its use in simulating and
For measuring
frequencyselectivity,thenotched-noise
procedure,
introducedby Pattersonand Nimmo-Smith,is regardedat the momentas
thebestmethodto avoidcueingeffects
andto takeoff-frequency
listening
intoaccount.
In thisstudy,a similarapproach
wasadoptedfor themeasurement
oflateralsuppression.
The amountof suppression
for a two-tone
masker,asa functionof the frequencyof the suppressor,
wasmeasuredin
the presenceof a notchednoise.Also in this paradigm,a fair amountof
suppression
wasfoundin a groupof 15normal-hearing
subjects.
For hearing-impairedsubjects,
and,surprisingly,
alsofor subjects
with a conductive loss,a graduallossof suppression
as a functionof hearinglosswas
observed.
Finally,theresultsarerelatedto auditoryfiltershapes
obtained
in simultaneous
andforwardmasking.
compensating for recruitment of loudness. Janet R. Lias and Mark
A. Clements(Schoolof ElectricalEngineering,GeorgiaInstituteof
Technology,Atlanta,GA 30332)
Amplitudecompression
techniquesutilizing both singleand multichannelfilteringsystems
havebeenproposed
for usein compensating
for
recruitmentof loudnessin hearingaids.Due to a varietyof limitations,
thesetechniques
haveshownonlymarginalsuccess.
The sinusoidal
model
of speechdevelopedby Quatieri and McAulay [IEEE Trans. Acoust.
SpeechSignalProcess.
ASSP-34,744-754 (1986) ] hasbeenusedto simulateandcompensate
for recruitment,usingthegeneraltheorydescribed
by Villehut [J. Acoust. Soc. Am. $6, 1601-1611 (1974)] and others.
Specifically,the modelsynthesizes
speechas the sum of sinusoldswith
time-varying
amplitudes
andphases.
Amplitudecompression
andamplificationcanbeperformed
onindividualsinusolds
to shapespeech
'tofit an
impairedperson'sresidualhearing.Conversely,
expansion
canbeusedto
Simulate the effects of recruitment. This model offers almost unlimited
10:30
flexibilityin areassuchasconsonantboostingand spectralshapingin any
portionof the spectrum.With a real-timeimplementation
of thismodel,
the parameters
canbeeasilyadjustedto suiteachperson'sneeds.
BS. Frequency masking patterns and "excess masking" in normalhearing and hearing-impairedlisteners. Margery A. Garrison, Anna
C. Schroder,and David A. Nelson (Hearing ResearchLaboratory,
Universityof Minnesota,2630UniversityAvenueS.E.,Minneapolis,MN
55414)
11:15
The presence
of "excessive
upwardspreadof masking"in high-frequencysensorineural
hearing-loss(HFSNHL) subjectshas beenpreviouslydemonstrated
byotherinvestigators.
Thisexcess
masking,defined
by predictionsfrom a "noise"modelof hearingloss,occursin the transitionregionbetweennormalandimpairedhearing.To examinethisphenomenonfurther, frequencymaskingpatterns(FMPs) were obtained
from two normal-hearingsubjectsand one HFSNHL subject.Using a
200-Hz narrow..band
noise(NBN) masker(90 dB SPL) with an upper
edgeat 520Hz, FMPs fromthe impairedeardemonstrated
excessmasking,whichit washypothesized
mightbeexplained
by an inabilityto "listenin the valleys"of the maskerenvelopebecause
of poortemporalresolution. To test this notion, the experimentwas repeatedusinga 40-Hz
NBN masker(90 dB SPL), which has lessrapid envelopefluctuations.
No differences
in the upwardspreadof maskingwereseenbetweenthe
200-and40-Hz bandwidth-equal
SPLmaskers.Whentheexperimentwas
repeated
withequalspectrum
levelmaskers,
the40-Hz NBN maskerproducedlessupwardspreadof maskingin bothnormal-hearingand hearing-impairedears.Thesedata suggestthat, for the HFSNHL subject,
excessive
upwardspreadof maskingcannotbecompletelyexplainedbyan
inabilityto "listenin thevalleys."[Work supported
by NINCDS.]
B11.Asimpleprocedurefor measuringiso-loudnesscontuurs.$.
B. Allen
(AT&T Bell Laboratories,Murray Hill, NJ 07974), P.S. Chien (Center
for Researchin Speechand HearingSciences,
City Universityof New
York ), andJ. L. Hall (AT&T BellLaboratories,Murray Hill, NJ 07974)
A procedurefor measuring
iso-loudness
contoursin normalandhearing-impairedsubjects
similarto thatusedby GellerandMargolishasbeen
devised[J. SpeechHear. Res.27, 20-27 (1984) ]. The stimuliareburstsof
noise«-octwide,centered
at 1-octintervals
from250Hz toto4 kHz. The
subjectisaskedto ratethestimuliaccordingto a six-pointscale,usingthe
descriptivewords "very soft," "soft," "OK," "loud," "very loud," and
"too loud." The instructionsincludea one-sentence
descriptionof each
loudness
category.Failureto respondis recordedas "nothing."In an
initial pass,the lowerand upperlimitsof the subject's
hearingrangeat
eachfrequencyare estimated.Theseinitial trials alsoserveto train the
subject.Following the initial pass,15 levels,logarithmicallyspacedbetweenthe measuredlimits at eachfrequency,are presentedin random
order,threetimeseach.The entireproceduretakesabout30 min to com-
plete,and it providesstableestimates(basedon test-retestmeasurements)of loudnessgrowthfunctions.Theseloudnessgrowthfuactions
are then replottedas iso-loudness
contours.Data from normal and hearing-impairedsubjectswill bepresentedalongwith their pure-tonethresholds.
10:45
11:30
B9. High-frequency audiomerry in platinum ototoxicity. Wouter
A. Dreschler and Rob J. A.M. v/d Hulst (Academic Medical Center,
Clinical Audiology, University of Amsterdam, Amsterdam, The
Netherlands)
In a groupof 144subjects(288 ears)medicallytreatedwith platinum
drugs,high-frequency
audiometrywas appliedat frequentintervalsin
orderto comparetheeffectsof threedifferentdrugadministrations:
highdoseels-platinumcures,low-doseels-platinumcures,and carboplatin
cures.In all subgroups,high-frequencyaudiometryconsiderablyenhancedthe early detectionof ototoxicity.Marked differencesbetween
cureswereestablished,
bothin the patternof onsetof the damageand in
the relationbetweendoseand damageseverity.For subjectstreatedwith
platinumderivatives,especially,the thresholdsat 14 kHz prove to be
important.The resultssuggest
that, for thesesubjects,
a singlemeasuring
frequencyshouldbetakenintoconsideration.
With a minimumof effort,
mostof theincreased
sensitivity
fora complete
high-frequency
audiogram
canbe reached.Finally,the predictivevalueof a thresholddeterioration
above8 kHz for a thresholddeteriorationin the conventionalrangeof
audiometricfrequencies
will be considered.
S5
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
B12. Effectsof fluctuatingconductivehearinglossin infancyon auditory
brain-stem responsesand binaural interaction measured at age 5.
Adele Gunnarsonand Terese Finitzo (University of Texas at Dallas/
Cailler Center, 1966 Inwood Road, Dallas, TX 75235)
The purposeof thisresearchwasto examinelong-termauditoryelectrophysiologic
effectsof earlyconductivehearingloss.Animal deprivation studiessuggestbrain-stemanatomicand physiologicalterationduring criticalperiods.Comparablehumanresearchis limited.The research
questionedwhetherauditorybrain-stemresponses
(ABR) and binaural
interaction(BI) at ages5-7 differeddependingon documentedpatterns
of earlyhearing.Stimuliwererarefactionclicksat 21.1/s, presented
binaurallyat 60 dB and monaurallyat 30, 60, and 80 dB HL. The BI was
derivedby subtractingsummedipsilateraland contralateralmonaural
responses
frombinauralresponses,
anddefinedasdeflections
whoseamplitudeexceeded
3 s.d.fromderivedprestimulus
amplitudes.
ResU{ts
indicatedthat wavesIII and V, and I-lII and I-V interpeaklatencies(IPL)
differedwhencontrolswerecomparedto experimentalsubjects.
WaveI,
the latency/intensityfunctionsat 30-60 and 30-80 dB, and III-V IPLs
114thMeeting:Acoustical
Societyof America
S5
The contribution of two acousticcues,voice onsettime (VOT) and
wereunchanged.
TheBI waspresent
in 8 outof9 controls
and8 outof9
childrenwithfluctuating
mildlosses
in infancy.Only4 outof 9 children
vowelonsetfrequencies,
to the perceptionof a TAD-DAD voicingcon-
withmoderate
asymmetric
losses
in infancy
hadBI at age5. [WorksupportedbyNIH No. 5 ROI NS 19675-03.]
trustwasexamined
fortennormal-heating
andsixhearing-impaired
children (3 FA: 50-95 dB HL) between6 and 12 yearsof age.Bothnatural
stimuliandhigh-qualitysynthesized
copiesof thesestimuliwereusedto
createfiveVOT continua(three naturaland two synthetic),in whichthe
vowelonsetcuewaseitherappropriate
or conflicting.
An adaptiveidenti-
11:45
ficationprocedurewasusedto determinephonemeboundaries
under
B13. Cue saliencein the perceptionof a stopvoicingcontrastby hearing
and hearing-impaired children. Valerie Hazan (Department of
Phonetics
and Linguistics,
UniversityCollegeLondon,4, Stephenson
Way, London NWl 2HE, United Kingdom), Lisa Holden-Pitt,
Sally Revoilc,Donna Edward,andJanetDrogc(Centerfor Auditory
andSpeechSciences,
GallaudetUniversity,Washington,
DC 20002)
TUESDAY
MORNING,
17 NOVEMBER
thesefive test conditions.Changesin spectralcharacteristics
at vowel
onsetdidproducesignificant
shiftsin phoneme
boundaryfor thenormalhearinggroup,but notfor thehearing-impaired
group.Similarphoneme
boundaries
wereobtainedby the normal-hearing
groupfor naturalcon-
tinuaandtheirsynthetic
counterparts.
However,highervaluesof standard error were observedfor syntheticstimulifor both listenergroups.
UMS 4 AND 5, 8:30 TO 11:55 A.M.
1987
Session C. Underwater
Acoustics I: Arctic Acoustics I
Dan 1. Ramsdale, Chairman
Naval OceanResearch
and Development
Center,NSTL Station,Mississippi
39529
Chairman's
Introductlon•:30
Invited Papers
8:35
C1. Geoacoustics
of the shallow-water
Arctic. $. E. Matthews(NumericalModelingDivision,Naval Ocean
Research
andDevelopment
Activity,NSTL, MS 39529-5004)
Fromtheperspective
of geology,
theshallow-water
regionsof the ArcticOceancanbedividedintotwo
provinces
of approximately
equalsize.Oneis characterized
byungiaciated,
thick,prograding
sedimentary
deposits,
whicharcfoundonthecontinental
shelves
of theBeaufort,Chukchi,andEastSiberian
Seas.The
otherischaracterized
by a glaciated
bank-trough
terrain,andincludes
thecontinental
shelfof theCanadianGreenland
ArcticandtheBarents,Kara,andLaptevSeas.Froma low-frequency
geoacoustics
pointof view,
theprograding
shelfprovince
consists
ofa fewtotensofmeters
ofpoorlysortedelastic
sediment
( 1.5-1.6kin/
s) that overliesan acousticbasementof consolidated
coarsesediment( 1.7km/s). The bank-troughprovince
hastwo distinctlydifferentenvironments:
shallowbandsthat consistof zero to severalmetersof'coarse
sediment
( 1.6-1.7kin/s) overlying
anacoustic
basement
of sedimentary
rock(3.5kin/s), anddeeptroughs
flooredby a fewtensof metersof poorlysortedsediment
(1.5-1.6kin/s) overan acoustic
basement
of
consolidated
sediment( 1.9km/s). Thesegeneralizations
mustbeconsidered
tentativebecause
of thecritical
scarcity
ofdata;however,
plane-wave
reflection
andnormal-mode
calculations
arepresented
forthesegeneric
environments to demonstrate their acoustic similarities and differences.
9:00
C2. Sound-speed
structureof the Arctic Oceanandthe GreenlandSeaMarginal Ice Zone.JohnL. Newton
(Polar ResearchLaboratory,Carpinteria,CA 93013)
Within the centralice-coveredArctic Basin,well awayfrom marginalinfluences,the verticalsound-speed
profilecanbecharacterized
by fourpositivesound-speed
gradientlayers.Theselayers(andtheapproximate
gradients
) area sutracemixedlayerextending
toa depthofa fewtensofmeters( • 0.016/s); a layerfromthe
baseofthemixedlayertothedepth(200-500m) ofthetemperature
maximumin theAtlanticwater( • 0.080/
s); a layerfromthetemperature
maximumto thebottomof theArianticwaterat about1000m ( •0.010/s);
andthedeepwaterextending
to theoceanbottom( • 0.016/s).Theconsistent
andnotabledifferences
evident
in thegeneralsound-speed
structure
of theCanadian
andEurasianBasins
canberelatedto thelargescale
ArcticOceancirculation.Profile-to-profile
variabilityandtheoccurrence
of smallverticalscalesound-speed
features,suchas relativeminima/maximaand steplikestructures,
are significantly
higherin the Eurasian
Basinthanin theCanadianBasin.Thesound-speed
distribution
withintheGreenlandSeaMarginalIceZoneis
dominated
bythepresence
of a strongoceanographic
front,theEastGreenland
PolarFront,whichmarksthe
boundarybetweenthecool,freshPolarwaterexitingtheArcticOceanandtheadjoiningwarmer,moresaline
Atlanticwater.Because
ofthisstrongoceanfront,profile-to-profile
sound-speed
variabilityin theMarginalIce
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J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
114thMeeting:Acoustical
Societyof America
S6
Zoneishighovershortdistances
andtimes.Thecomplex
sound-speed
structure
anditshighvariability
result
fromvariousinteractions
between
thetwowatermasses
whichcantaketheformofeddies,
intrusive
layers,and
steplikefeatures.
9:25
C3. Recentadvancesin Arctic high-frequency
acoustics.R. œ. Francois(Applied PhysicsLaboratory,
Universityof Washington,Seattle,WA 98195)
In thepastfewyears,research
in Arctichigh-frequency
acoustics
(f> 5 kHz) hasbroughtabouta much
betterunderstanding
of theeffectof environmental
factorson acoustics.
Our knowledge
of theeffectof water
properties
continues
to increase
aswell-knownphenomena
areroutinelytreatedin greaterdetail.Ice properties,on theotherhand,andtheeffectof thesepropertieson acoustics,
requirenewideasanddiligentresearch.
For example,and perhapsof foremostimportance,considerreflections
from seaice.Studiesof the reflecting
propertiesof the lowersurfaceof seaice,with its dendriticlayer,showthat at low frequencies
the reflection
coefficient
at normalincidence
depends
onlyon thebulkproperties
of themedium.At higherfrequencies
(up
to 200 kHz) Gaussiandistributionsfor reflection coefficientsare observed,with standard deviationsthat
increase
with frequencyandaverages
that decrease
with frequency,asmuchas28 dB belowthat predictedby
bulkproperties
alone.Studiesof thetargetstrengthcharacteristics
of iceblockshapes
haveshownthat rigid
body theoryfor simpleshapes,while goodfor hard ice surfaces,only crudelypredictsactualresponsefor
freezingsurfaces.
As for in situicekeels,thevariationin returnwith frequencyshowsthat reflections
areoften
the coherentsumof severalreflectorsnearthe samerangeand closeenoughin azimuththat suchreturns
appearto bepointlike.[ Work is supported
by Officeof NavalTechnology.
]
9:50
CA.A reviewof appliedArctic acousticmodels.R. C. Cavanagh,J. A. Davis (PlanningSystems,Inc., 7925
WestparkDrive, McLean,VA 22102), andJ. S. Hanna (SAIC, 1710GoodridgeDrive, McLean,VA 22102)
Basicacousticmodeldevelopmentrelatedto the Arctic environmenthas beencarriedout by various
researchers
over the past25 years.This work is beingincorporatedinto appliedmodelsfor propagationand
noisethat attemptto provideusefulpredictivecapabilitygivensuitableenvironmental
databases.A reviewis
presented
ofthecandidatetheoriesandsomehistoryof theirdevelopment.
In particular,icescattering
theories
aredescribed
thatshowpromise
ofutilityandtheirincorporation
intotheseveralstandardpropagation
models
isdiscussed.
Somecomparisons
of thesemodelswith dataare presented
and the outstanding
issuesrelatedto
modeldevelopment
and the adequacy
of existingdataarepresented.
Althoughthe development
of a correspondingambient noisemodel is a much lessmature activity, current attemptsat such developmentare
reviewed.[Work supportedby the ASW EnvironmentalAcousticSupportProgram.]
10:15
C5. High-frequency acoustic backscatter from the Arctic ice canopy: Theory and experiment. Suzanne
T. McDaniel (Applied ResearchLaboratory,PennsylvaniaStateUniversity,P.O. Box 30, StateCollege,PA
16804)
The methodof physicalopticsisappliedto treatthebackscatter
of high-frequency
acousticsignalsfromthe
Arctic ice canopy.Theoreticalresultsare obtainedfor both the meanbackscattering
strengthand the spatial
coherence
of the scatteredfield.The meanbackscattering
strengthis foundto bedependenton the fractional
surfacearea coveredby underwaterice ridges.Using measuredice distributions,the variabilityin mean
scattering
strengthis predictedto varyby at most + 2.5 dB from its averagevaluefor a widevarietyof ice
conditions.
The theoryis thenappliedto treatthe spatialcoherence
of backscatter.
The coherence
is foundto
dependon the ice draft distributionand ensonified
surfacearea.The resultsof experimentsto measurethe
verticalspatialcoherence
of bistaticbackscatter
arepresented.
Theseresultsnotonlyconfirmthetheoretically
predicteddependences
on measurement
geometrybutalsosupportpredictions
of therelativeimportanceof ice
roughness
versusensonification.
[Researchsupported
by ONT with technicalmanagement
by NORDA.]
10:40
C6. Energy partitioning for very-low-frequency,long-range acoustic propagation in the Arctic. A.
B. Baggeroer(Massachusetts
Instituteof Technology,Cambridge,MA 02139), G. L. Duckworth (Bolt
Beranekand
NewmanLaboratories,
Cambridge,
MA 02238),andE. K. Scheer(WoodsHoleOceanographic
Institute, Woods Hole, MA 02543)
In long-rangeacousticpropagationin the Arctic, very-low-frequencysignalsinteract with both the ice
canopyandthe bottom,bothof whichintroduceloss.Signalsfrom a sequence
of long-range(340-kin) shots
detonatedat severaldepthswererecordedon a multichannelarray and resolvedaccordingto their horizontal
phasevelocityand frequencycomponents
to separatethe losseffectsof the thesetwo boundaries.Sourcelevels
andgeometric
losses
basedupona determined
sound-speed
modelweresubtracted
to arriveat an absorptive/
scatteredlossmeasurefor eachresolvedpath and frequency.Thesereduceddata were usedto estimatethe
S7
J. Acoust.Soc. Am. Suppl.1, Vol. 82, Fall 1987
114th Meeting:AcousticalSocietyof America
S7
partitioningof energyaccordingto phasevelocityand frequencyfrom the icecanopyand the seafloor.At
frequencies
below20 Hz, bottominteractingsignalsaccountfor morethan 50% of the receivedenergyobservedat the array on almostall the shots.
11:05
C7. Arctic ambientnoisemechanisms.
Ira Dyer (Massachusetts
Instituteof Technology,Departmentof
OceanEngineering,
Cambridge,
MA 02139)
The studyof ambientnoisecan bedividedintotwo categories,
onedealingwith thecorrelationof averaged
noisewith the slowevolutionof environmental
parameters,and the otherconcentrating
on detailsof the ice
fractureprocesses
that ultimatelygiveriseto individualnoiseevents.Recentprogressin both categories,
especially
atlowfrequencies
(3-100Hz) where
significant
results
appear
tobeathand,
isreviewed.
Thoughts
onhigherfrequencies
( 100-3000Hz) arealsogiven,forwhichit seems
likelythattheenvironmental
correlates
anddetailedsourcemechanisms
areof a differentcharacterthanat low frequencies.
Finally,distinctions
are
drawnbetweenpackiceof thecentralArcticandlow-concentration
iceof themarginalicezone,withrespectto
their likely mechanisms
of noisegeneration.[Work supportedby ONR, Arctic ProgramOffice.]
11:30
C8. Arcticdatabuoys--Anul•late.Beaumont
M. Buck(PolarResearch
Laboratory,
Inc.,6309Carpinteria
Avenue,Carpinteria,CA 93013)
A 1983paper,"Arcticdatacollection
theeasyway--Data buoys"[J. Acoust.Soc.Am. Suppl.1 74, S2
(1983)], presented
data buoysas a partialsolutionto the problemsand limitationsinherentto manned
operations
in theArctic.Thepresent
paperdescribes
thesuccesses
andfailures
ofthesedevices,
asappliedto
Arcticunderwater
acoustics,
in theintervening
yearsandwhathasbeendonewiththelargequantities
ofdata
that theyhavegenerated.
Thiswill includewide-area,synopticcollectionof ambientnoiseleveldata,aswellas
first-ever
measurement
of low-frequency
propagation
duringthesummertime
in the CentralArcticusing
autonomous
cwprojectorandreceiving
databuoys.Plansforevenmoresophisticated
devices
to beinstalledin
1988arediscussed.
[Work supported
by U.S. Navy.]
TUESDAY
MORNING,
17 NOVEMBER
POINCiANA
1987
ROOM, 9:00 TO 10:40A.M.
SessionD. Architectural AcousticsI: Acoustical Design of Renovated Performance Facilities I
ChristopherJaffe,Chairman
Jaffe Acoustics,
Inc., 114A WashingtonStreet,Norwalk, Connecticut06854
Chairman's
Introductions9:00
Inoited Papers
9:10
D1. The movie!•alaceas!•erformingartscenter. PeterJ. George(PeterGeorgeAssociates,
Inc., 34West 17th
Street, New York, NY 10011)
Many movie theaters in downtown neighborhoodshave been saved from demolition by their renovation
andrecyclingasperformingartscenters.While thesespacesoftenhavephysicalcharacteristics
that aredeemed
acoustically
desirable,thereare oftenmanyfeaturesthat are detrimentalto a goodacousticalperforming
environment.
Thispaperdescribes
typicalattributesanddeficiencies
withmethodology
to improvethelatter.
9:40
D2. SomeunusualrenovationI•rojects.David L. Klepper (Klepper Marshall King Associates,
Ltd., 7
Holland Avenue, White Plains, NY 10603)
A comparison
of several
differentrenovation
projects
indicates
thatanacoustical
consultant
mustbevery
flexible in adopting a particular set of recommendationsfor the acoustical,architectural, and restoration
S8
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall 1987
114thMeeting:AcousticalSocietyof America
S8
requirements
of a particularproject.In oneproject,sound-reflecting
panelsmay be appropriate,in another,
definitely
not.In oneproject,an idealcentralclusterloudspeaker
system
maybeappropirate,
in a second,
it
mustbesupplemented
by delayedunderbalcony
loudspeakers,
whilea third wouldbestemployverticallinesourceloudspeakers,
a fourtha horizontallinesource,anda fiftha distributeddelayedloudspeaker
system.By
meansof slides,the differences
betweentheseseveralprojects,wh;.chincludea universityconcerthall, the
conversion
of a motionpicturetheatreto a multi-useperformingarts centerwith emphasison symphony
concerts,a universitytheatre,and two 19thcenturyoperahousesrestoredasmulti-useperformingartscenters
will beexplored.
Onecommonthreadrunsthroughall of them,however;
all makemaximumuseof livesound
beforethe useof electronics,with minimumuseof sound-absorbing
treatment.
10:10
D3. Adaptivereuseof existingauditoria.J. ChristopherJaffe(JaffeAcoustics,Inc., 114A WashingtonStreet,
Norwalk, CT 06854)
The adaptivereuseof existingauditofiais an extremelycostefficientway for communities
to create
contemporary
"stateof theart" performance
facilities.
Thekeytothesuccessful
culmination
of sucha facility
isa cleardefinitionof theprogramuseofthespaceandanunderstanding
between
theclientandtheconsultant
thatall availableacoustic
techniques
canbeutilizedto achievefinaldesigngoals.Thispaperwill discuss
the
adaptivereuseof a numberof buildings
asdiverse
asa library,a unionhall,a WPA builtart decomusichall,
anda threetheatre/filmcomplex.
TUESDAY' MORNING,
17 NOVEMBER
TUTTLE
1987
SOUTH ROOM, 9:00 TO 11:20 .A.M.
SessionE. Noise I: Propertiesand New Applicationsof PorousMaterial
Gilles A. Daigle, Chairman
Divisionof Physics,
NationalResearchCouncil,Ottawa,OntarioK1A OR6,Canada
Chairman's
Introduction--9:00
Invited Papers
9:05
El. Theoriesfor soundpropagationin rigid-framedprous materials. Keith Attenborough(Engineering
MechanicsDiscipline, Faculty of Technology,The Open University, Milton Keynes MK7 6AA, United
Kingdom)
An historicaloverviewof thedevelopment
of theoriesfor soundpropagationin rigid-framedporousmedia
is offered.Phenomenological
and microstructuraltheoriesare contrasted.Microstructuralapproaches
may
starteitherfromspecifications
of thegeometrical
formof thesolidframeor fromspecifications
of thegeometri-
calformofthepores.
Theformerapproach
isparticularly
useful
fordescribing
acoustical
properties
offibrous
materials.The latter approachhasthe longesthistory,the widerapplication,and is the basisof manyrecent
developments
in thedynamictheoryof poroelasticity.
In oneformof thepore-based
theory,consideration
is
givento the incorporation
of dynamiceffectsof poreshapeand irregularityandsteadyflow tortuosity.An
alternativeform resultsfrom a morerigorousapproachto the effectson viscousdragand thermalinteraction
with porewallsof the inclinationof poreaxesto the macroscopic
pressuregradient,i.e,, dynamictortuosity
effects.By comparingtheoreticalpredictionswith experimentaldatafor sand,leadshot,glassheads,and snow,
both the usefulness
and the currentlimitationsof theoriesthat usemicroscopicpore-baseddescriptionsand
their variousapproximations
areexplored.
9:30
E:•. Towards a method for predicting absorption coefficient rather than measuring it in a reverberation
chamber.J. Nicolas (G.A.U.S., G•nie m•canique,Universit(•de Sherbrooke,Sherbrooke,QuebecJ1K 2RI,
Canada)
The modelizationof the impedanceof fibrousand rigid processmaterialis discussed.
For fibroussoft
materialsuchas fiberglass,it will be shownthat Delany and Bazley'smodel [Appl. Acoust.3, 105-116
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J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
114thMeeting:Acoustical
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S9
(1970)] isquitereliablefor normalspecific
impedance
aswellasfor obliqueincidence.
Experimental
validationsaredonevia thetwo-microphone
method[ submitted(1987) ] ( normalandoblique)andvia the indirect
methodoftheequivalent
flowresistivity
(obliqueonly).Performance
of lessclassical
typesofsoftmateriallike
felt is not wellquantifiedby DelanyandBazley,showingclearlythelimitationof thisone-parameter
model.
For rigid porousmaterial,the impedance
behavioris generallymorecomplex.Productslike ceramicsand
cement-woodfiber have beenunder investigation.Flow resistivity,porosity,and tortuosityhave beenmeasuredand introducedin Attenborough'sfour-parametermodel [J. Acoust.Soc.Am. 73, 785-799 (1983)].
Thisleavesa noteasilymeasurable
parameter,
theshapefactor,whichisusedasan adjustable
parameter.For
theserigid materials,goodagreementwill be foundbetweenpredictionand experimental
dataevenfor the
importantoscillations
encountered
forhighfrequency.
Thisindicates
that,withsimplesetups
forthemeasurementof physicalparameter,one may be ableto calculateabsorptioncoefficient
ratherthan measuringit
especially
fornormalincidence.
However,thelinkbetween
a calculated
diffuse
fieldabsorption
coefficient
and
theonemeasured
in a reverberation
chamber
is notclearat present.
9:55
E3. Optimaluseof noisecontrolfoams.J. Stuart Bolton(Ray W. HerrickLaboratories,
PurdueUniversity,
West Lafayette,IN 47907)
Polyurethane
foamis usedwith increasing
frequencyin noisecontrolapplications
owingto its easeof
handlingandmanufacturability.
Until recentlyit hasnotbeenpossible
to predictitsacoustical
behaviorwith
theaccuracy
that is possible
for fiberglass,
thusdiscouraging
the useof foamin criticalapplications.
Now
theoretical
modelsgoverning
one-dimensional
wavepropagation
in noisecontrolfoamshavebecomeavailable
thathavebeenshownto becapableof reproducing
normalincidence
absorption
andtransmission
measurementsaccurately.
Thesetheorieshavebeenusedto predictthebehaviorof foamin severalabsorption
and
transmission
applications.
In confirmationof largelyanecdotalevidence,it hasbeenfoundthat the acoustical
behaviorof foamis very sensitiveto its methodof applicationto backingsurfacesand to the way surface
coatingsare applied.In addition,it hasbeenpossible
to identifyoptimumtreatmentconfigurations.
These
studieswill be summarizedhere.Progresstowardsfull three-dimensional
foammodelswill alsobe described.
Suchmodelsarenecessary
to allowthe prediction
of obliqueincidence
soundtransmission
andabsorption.
Finally,theoryandexperiments
relatedto a newuseof foamasa vibrationdampingmaterialwill bereported.
10:20-10:25
Break
10:25
E4. Measurementof acousticimpedance
of soundabsorbingmaterialsin a free field at low frequencies.
Y. Champouxand J. F. Allard (MechanicalEngineeringDepartment,Universit6de Sherbrooke,
Sherbrooke,
Qu6becJ1K 2R 1, Canada)
Thetwo-microphone
technique
allowstheprecise
measurement
ofacoustic
velocity
andconsequently
the
determination
ofacoustic
intensity.
Usingthisprinciple,
a methodhasbeenproposed
tomeasure,
inafreefield,
theacoustic
impedance
ofsoundabsorbing
materials.
Goodresults
wereobtained
forfrequencies
rangingfrom
700 Hz to 4 kHz [J. F. Allard et al., J. SoundVib. 114(2) (1987)]. Recently,it hasbeendemonstrated
theoretically[Y. ChampouxandA.L'Esp6rance,
J. Acoust.Soc.Am. Suppl.1 80, S56 (1986) ] that for low
frequencies,
evenif thesourceisseveralmetersfromthesample,thespherical
natureof thewaveshasto be
takeninto account.This paperpresents
experimental
evidence
that confirmsthat the modelingcorrectly
describes
thephenomena.
Furtherseveralrefinements
to the experimental
technique,
allowingprecisemeasurementsfor frequencies
as low as 250 Hz, will be demonstrated.
ContributedPapers
10:50
DAMPA ceiling products.Soundabsorptionvaluesfor the textile are
ES. The replacementof mineral woolin perforatedceilingsby a laminated
textile. Glenn H. Frommer (DAMPA
A/S, 5690 Tommerup,
Denmark )
A layerof 0.2-mmtextilelaminatedontoa perforated
metalbandhas
beendeveloped
to replaceinlaysof 12-mm34-k/m3 mineralwool in
S10
J. Acoust.
Soc.Am.$uppl.1, Vol.82, Fall1987
15%-20% betterat frequencies
under315Hz, andgenerallyhigherat all
otherfrequencies,
NRC = 0.75.Thisexceptional
propertyisachieved
by
optimizingthestreaming
resistance
of thetextileanditslamination.The
ceilingunitsconformwith therequirements
of theBritishBuildingRegulations,1976,for a class-0surfaceandtheASTM requirements
for smoke
density.In contrastwithotherporousmatedhals,
vibrationaltestsshowno
114thMeeting:
Acoustical
Societyof America
$10
evidence of fallout. The Danish Environmental
Prize has been awarded
planewaveexcitation.In orderto obtainvalidhigh-frequency
data,a tube
with a small crosssectionis required.But, quite often, the absorptive
for the development
of theseproducts.
properties
ofthesmallsample
ofmaterialthatistestedarenotrepresentaneeringmethodhasbeendescribed[M. A. Nobile,Pro½.NOISE-CON
'87,PennStateUniversity,
8-10June1987,pp.611-616]thatshows
that
11:05
E6. The measurementof absorptioncoefficientand acousticimpedance
using spherical waves and a transfer function method. Matthew
A. Nobile (IBM AcousticsLaboratory,DepartmentC18, Building704,
P.O. Box 390, Poughkeepsie,
NY 12602)
The normal-incidence
absorption
coefficient
(or compleximpedance)
ofanacoustical
materialisusuallymeasured
in a standing
wavetubeusing
TUESDAY
MORNING,
17 NOVEMBER
1987
tive
of
those
of
the
larger
samp
from
whic
it
has
bee
tak
An
en
largesamples
of materials(or outdoorgroundsutraces)canbeevzduated
usingspherical
wavesin a hemi-anechoic
environment.
Aswiththestanding-wavetube method(per ASTM E-1050), this new methodutilizes
randomnoiseexcitationand computesthe transferfunctionbetweentwo
closelyspaced
microphones.
Theaccuracy
islimitedprimarilybydiffraction from the edgesof the finitesample,whichis not takeninto account.
Thispaperwill address
thetheoretical
aspects
of theproblemandpresent
somerecentexperimentalresults.
TUTTLE
CENTER ROOM, 9:00 A.M. TO 12:05 iP.M.
SessionF. Physical AcousticsI: Nonlinear Acoustics
Mark F. Hamilton, Chairman
Department
of Mechanical
Engineering,
University
of Texasat Austin,Austin,Texas78712-1063
Chairman's
Introductionre9:00
ContributedPapers
9:35
9:05
Fl. Nonlinear compressibilitycorrectionsto induced hydrodynamic
mass: Consequences for small amplitude supersonic modes.
S. Putterman,P. H. Roberts (Physicsand MathematicsDepartment,
Universityof California, Los Angeles,CA 90024), and W. Fiszdon
(Departmentof Fluid Mechanics,
PolishAcademyof Sciences,
00-049
Warsaw, Poland)
The inducedmassof an objectaccelerating
throughan isotropicfluid
hascontributions
due to the fluid'scompressibility
that are anisotropic
andnonlinearin the velocity.Thiseffectcanleadto pronounced
amplitudedependence
intheresonant
frequency
ofsupersonic
modes.
Onesuch
exampleto bepresented
involvestheplasmawavethat propagates
in 2-D
F3. Nonlinearity parametersfor superfluidhelium. M. S. Cramer and
R. Sen (Departmentof Engineering
Scienceand Mechanics,
Virginia
PolytechnicInstituteandStateUniversity,Blacksburg,
VA 240611
)
Thenonlinear
propagation
of second-sound
in He II nearoneof the
zerosofthequadratic
steepening
parameter
associated
withtheB/.4 ratio
is considered.
It is shownthat thecorrectdescription
at thesepressures
andtemperatures
requires
anadditionalnonlinearity
parameter.
Newexpressions
for the nonlinearsoundandshockspeedare givenandcomparedto experiment.
9:50
arraysof ionsin He4 witha velocitythatis tentimesthe He4 sound
velocity.[Work orS.P. supported
byDOE andworkofP.H.R. supported
by ONR. ]
F4. Refractionof finite amplitudeacousticwavesat e plane fluid-fluid
interface. Frederick D. Cotaras and David T. Blackstock (Applied
ResearchLaboratories,The University of Texas at Austin, P.O. Box
8029, Austin, TX 78713-8029)
9:20
F2. Sound generation from a transonically moving laser. Rao
J. Chandrasekharand Ilene J. Busch-Vishniac(Applied Research
Laboratories,The Universityof Texasat Austin, P.O. Box 8029, Austin,
TX 78712)
Experimentalinvestigations
of the soundgeneratedunderwaterby a
movinghigh-power
lasersourcehaveshownroughlya 25-ribboostin the
pressure
if thesourcemovesat Maeh one.A three-pronged
approachto
studyingthistransonicamplification
phenomenon
hasbeenused:an analytical examinationof the effectof includingfirst-orderentropy produc-
tion termsin theequationof state,a numericalinvestigation
of the effect
of sourcevelocityon thesoundgenerating
efficiency,
andanexperimental
test of the validity of superposition
as a functionof sourcevelocity.Resultsshowthat nonlinearitiesand entropyproductioncannotexplainthe
amplification
phenomenon.
Further,theacoustic
efficiency
isshowntobe
substantiallylower for a transonicsourcethan for a subsonicsource.
Hence,the transonicamplificationphenomenonis still not explainable.
[Researchsupportedby ONR. ]
$11
J. Acoust.Soc. Am. Suppl. 1, Vol. 82, Fall 1987
One of the oldest and most venerable laws of acoustics is Snell's law.
Butdoesthislawholdfor finiteamplitudesound?
Byfollowingthepathof
a wavelet(point on a waveform),the followingform of Snell'slaw for a
finiteamplitudewaveis derived:
sin 0,/sin O, = (c• + •u, )/(c• + lg•u•),
where 0, c,/g, and u are angle, small-signalsound speed,nonlinearity
coefficient,and particle velocity,respectively.Subscriptsi, t, 1, and 2
denoteincidentwave,transmittedwave,fluid 1,andfluid2, respectively.
SinceO,ispredicted
tovaryfromwavelettowavelet,thetransmitted
wave
fieldcannotbetruly planar.However,by followingthepathof individual
wavelets,the waveformof the transmittedsignaliscomputedat anypoint
in the field. [Work supportedby ONR.]
10:05
FS. Effectsof osci!latorymotionon crystal growth.Charles Thompson
andVincet Mehta (Departmentof ElectricalEngineering,
Universityof
Lowell, 1 UniversityAvenue,Lowell, MA 01854)
114th Meeting:AcousticalSocietyof America
S11
Thisworkexploreshowthermallyinducedinstabilities
drivenby the
oscillatorymotionof a heatedfluidaffectthe growthof a semiconductor
crystal.The mechanisms
governinginteractionbetweentheinterfacetemperatureanditsgrowthwill bepresented.It will beshownthat the dynamic characteristicgrowthfront can bedescribedby a nonlineardifferential
equation.
Preliminary
resultsof ouranalysis
suggest
thatmorphological
defectsin bulkmaterialscanbeattributedto theaccelerated
growthrate
that occursin response
to highunsteadytemperaturegradients.The theoryformulated
suggests
methods
thatcouldbeusedin controlling
quality
of semiconductor
crystals.Finally, the implicationsof this theoryin formulatingbetterprocesses
for manufacturing
bulk semiconductor
materi-
( Khokhlov-Zabolotskaya-Kuznetsov
equation).Theequation
issolved
numericallyfor two monochromatic
sources
by usinga generalization
of
the methodof Hamilton, Naze Tj$tta, andTjStta [ J. Acoust.Soc.Am. 78,
202-216 ( 1985) ]. Propagationcurvesand beampatternsfor the various
components
of the acousticfield (harmonicsand combinationfrequencies)arepresented.
Specialattentionis givento thedifference
frequency
component.
The analysisextendsto rangesbeyondthe shockformation
distance.Varioussourcelevels,absorptionlengths,and downshiftratios
are considered.The resultsare comparedwith that obtainedfor sources
operatingat moderateintensity(quasilinear
theory).
alswill beoutlined.[Worksupported
byAnalogDevicesProfessorship.
]
11:05
10:20
F9. Comparisonof tissuecompositionmodelsvia the measurementof the
nonlinear parameter of mixtures. Erich Cart Everbach and Robert
F6. Effects of boundary and fluid variations on the enhancement of
E. Apfel (Departmentof MechanicalEngineering,
Yale University,
diffusive transport. CharlesThompson (Department of Electrical
Engineering,Universityof Lowell, I UniversityAvenue,Lowell, MA
2159 Yale Station, New Haven, CT 06520)
01854)
The role that bothboundaryvibrationand unsteadyfluidmotionhave
in enhancingdiffusivetransport will be discussed.In particular, how
acoustically
inducedvorticaldisturbances
interactwitha two-dimensional temperaturefield will be examined.Suchvorticaldisturbances
have
beenshownto bethree-dimensional
[ C. Thompson,"Stabilityof a Stokes
boundarylayer,"J. Acoust.Soc.Am. 81, 861 (1987) ]. Hence,parametric
interactionbetweenthe flow and temperaturefield to the major mechanism for diffusionenhancement
is expected.Numericalresultsdemonstratingthe degreeof augmentation
will be presented.[Work supported
by AnalogDevicesProfessorship
and NSF. ]
Recently,severalmodelshavebeenproposedfor predictingtissue
composition
(percentwater,protein,and fat) from physicalmeasurementsmadeonthebulk material[ Sehgaletak, UltrasoundMeal.Biol. 12,
865-874 (1986); and R. E. Apfel, J. Acoust.Soc. Am. 79, 148-152
(1986) ]. Eachmodelrequires
themeasurement
ofseveralbulkproperties
suchasdensity,soundvelocity,andtheacousticnonlinearityparameter
B/.4. Thesemodelsareintendedto aidthediagnosis
andanalysisof tissue
pathology.
Theyalsosharewithacoustic
absorption
andnuclearmagnetic resonance
(NMR) techniques
theprospect
of elucidating
thecharacteristics
ofintermolecular
interactions
in tissues.
Asreportedat a previous
meeting[E. C. Everbach
andR. E. Apfel,J.Acoust.Soc.Am. Suppl.180,
S4 (1986)], a systemto accurately
measure
theB/.4 valueof liquidsand
semiliquid
substances
hasbeendeveloped.
In orderto assess
thesensitivity of thetissuecomposition
modelsto differences
in molecularstructure,
B/.4 hasbeenmeasured
systematically
for variousproteinsandlipidsfor
which acousticabsorptionand NMR data are known.To determinethe
10:35
F7. Noncollinear interaction of a tone with noise. StephenJ. Lind
(Applied ResearchLaboratories,The University of Texas at Austin,
Austin, TX 78713-8029) and Mark F. Hamilton (Department of
MechanicalEngineering,
The Universityof Texasat Austin,Austin,TX
78712-1063)
validityof eachmodel,thebulkproperties
of water-protein-fatmixtures
are measured
and the model'spredictions
to the knowncomposition
of
eachmixturearecompared.
Usingthedataobtained,theexistingmodels
will be comparedand suggestions
for extendingthemto moregeneral
systemswill be offered.[Work supportedin part by the U.S. O•ce of
NavalResearch
andby the NationalInstitutesof HealththroughGrant
2-R01-GM30419-04.]
The noncollinearinteractionof a tone with noiseis investigatedexperimentallyin an air-filledrectangularduct. A low-frequency
bandof
noisein the (0,0) modeinteractswith a high-frequencypure tone in the
(1,0) mode.A quasilinear
theorydeveloped
byHamiltonandTenCate[J.
Acoust.Soc.Am. 81, 1703-1712 (1987) ] for the noncollinearinteraction
of two puretonesisgeneralized
to predictthesumanddifference
frequency sidebands
of noisecreatedaroundthehigh-frequency
tone.Whentwo
pure tonesinteract, the resultingsum and differencefrequencysound
oscillates
in spacewith a periodicitythat dependson the frequencies
and
interactionangleof the primary waves.The bandof low-frequencynoiseis
thusupshiftedto sidebandswhosespectralshapesare scallopedin appearance. The scallopingbecomesmore pronouncedwith range from the
source,and increasingthe interactionanglereducesthe overalllevelsof
the sidebands.
Theory and experimentare shownto be in goodgeneral
agreement.[Work supportedby NSF andby ONR.]
10:50
FS. Propagationand interactionof two collinearfinite mnplitudesound
beams. Jacqueline Naze Tj•tta, SigveTj•tta (Department of
Mathematics,The Universityof Bergen,5007 Bergen,Norway and
Applied ResearchLaboratories,The University of Texas at Austin,
Austin, TX 78713-8029), and Erlend H. Vefring (Department of
Mathematics,The University of Bergen, 5007 Bergen,Norway and
Departmentof MechanicalEngineering,The Universityof Texas at
Austin, Austin, TX 78712-1063)
The propagationand interactionof collinear,high-intensitysound
beamsare investigatedwithin the schemeof the parabolicequation
$12
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
11:20
FI0. Forcedradial oscillationsof singlecarlrationbubbles:A comparison
of experimental and numerical studies. Co. Holt and L. A. Crum
(Physical AcousticsResearchLaboratory,Departmentof Physics,
Universityof Mississippi,Oxford, MS 38677)
Refinements
of anopticalscatteringtechniquepreviouslyreported
Acoust.Soc.Am. Suppl.I 80, S24 (1986) and Suppl.I 81, S26 (1987)]
havemadepossible
a quantitativecomparison
of theexperimentally
obtainedradiusversustime (R-t) curvewith previously
obtainednumerical
R-t results.The response
of bubbles
withequilibriumradiifrom20-80
to a 22-kHz acousticfield is presentedand comparedto the resultsof
previously
published
numericalmodels[ see,forexample,W. Lauterborn,
$. Acoust.Soc.Am. 59, 283-293 (1976) andMiksisandTing, J. Acoust.
Soc.Am. 81, 1331-1340(1987) ]. [ Work supportedby ONR. ]
11:35
Fll. Focal-point shifts for the reversed wave in acoustical phase
conjugationexperiments:Paraxial analysisand analogy with optical
holography.Philip L. Marston (Department of Physics,Washington
StateUniversity,Pullman, WA 99164)
A phase-conjugate
mirror is onethat reverses
an outgoingwavefront
114thMeeting:Acoustical
Societyof America
$12
sothatit propagates
backtowardthesource.
Recentexperiments
[ Kus-
11:SO
toy et aL, Soy.Phys.Acoust.31, $17-518 (1985)] indicatethat wave
FI2.
frontreversal
canb• established
through
theinteraction
ofa pumpwave
of frequency•witha signalof frcqucncy•thatdiverges
froma point
source.
Thenonlinear
medium
wheretheinteraction
occurs
isa thinlayer
ofgasbubbles
inwater.In these
experiments,
however,
thefrequencyf•
of
P. O. Box 4005, Champaign, IL 61820-1305), Steve Franke
(Departmentof Electricaland ComputerEngineering,Universityof
Illinois, Urbana Champaign, Champaign, IL 61820), and
Richard Raspet(PhysicalAcoosticsRcsearchGroup,
Thc Universityof
Mississippi,
University,MS 38677)
thereversed
wavedifferedfromm= 60 kHz since
f3 =f, --f• ----40 kHz
andf, = 100kHz. The presentresearchis concerned
with the useof a
paraxialapproximation
to predictthe locationof the focalpointof the
reversed
wave.Thenormalsofthewavefrontsoftheinteracting
wavesare
assumed
to be nearlyperpendicular
to the bubblelayer. Let z2 and z3
denotetherespective
distances
of the sourceandfocalpointsfrom the
layer.If thepumpwaveisa planewavepropagating
perpendicular
to the
layer,theanalysis
gives% = ( •/•)z2, sothatz•z 2 whenf3-•f•. This
resultisanalogous
to theimagelocationin opticalholography
for cases
The U.S. Army ConstructionEngineeringResearchLaboratoryhas
performedsimultaneous
meteorological
and acousticmeasurements
of
soundpropagation
fromsmallexplosives.
Categorized
experimental
data
havebeenplacedinto groupsbasedon similarityof variationin sound
speedwith height.Usingthesedatagroupsasinputto the pulsefastfield
program[J. Acoust.SOC.
Am. 79, 628-634 (1986) ], predictions
of sound
levelsare produced.The comparisonof thesepredictionsand m(asured
wherethe recordingand reconstruction
processare carriedout at differ-
ent wavelengths[J. W. Goodman,Introductionto Fourier Optics
(McGraw-Hill, SanFrancisco,1968)]. Otherapplications
of thisanalogywill benoted.[Worksupported
by ONR.]
TUESDAY
MORNING,
17 NOVEMBER
Blast noi•e propagation prediction. Carolyn R. Shaffer
(Departmentof Electricaland ComputerEngineering,
Universityof
Illinois.Urbana-Champaign,
Champaign,
IL 61820and USA-CERL,
levels will be discussed.
1987
TUTTLE
Session G. Structural Acoustics and Vibration
NORTH ROOM, 9:00 TO 11:30 A.M.
I: Active Vibration
Control
Vijay K. Varadan, Chairman
ResearchCenterfor theEngineeringof Electronicand AcousticMaterials,Pennsylvania
State University,UniversityPark,
Pennsylvania16802
Chairman's lntraduction--9:00
Invited Papers
9:•$
GI. Active controlof soundradiationfrom platesusingforce inputs.Chris R. Fuller (Departmentof
MechanicalEngineering,Virginia Tech, Biaeksburg,VA 24061)
Recentlymuch interesthasarisenover the useof activecontrol methodsto reducesoundfields.The usual
methodisto useanarrayof secondary
acoustic
sources
positioned
in theradiatedfield.Thistechnique
has
provedsomewhat
successful,
butonedifficultyistheexcitation
of unwanted
radiation(controlspillover
) that
necessitates
theuseofmanycontrolsources.
A newtechnique
isstudied
in whichtheactivecontrolisapplied
directlyto theradiating
surface
bya forceinput.Theadvantage
of thisapproach
is that,by reducing
plate
response,
the radiatedsoundlevelswill be controlledglobally.The systemconsideredconsistsof a baffled
clampedcircularelasticplateexcitedononesidebyanincidentacoustic
planewave.Reductionoftheradiated
acoustic
fieldontheothersideoftheplateisachieved
bya pointforceapplieddirectlytotheplatesurface.
The
complex
amplitude
ofthecontrolforceisdetermined
mathematically
suchthattheradiatedacoustic
intensity
integrated
overvariousrequiredsectors
isminimized.Resultsobtaineddemonstrate
excellent
globalreduction
in the radiatedfieldlevelsfor the singlecontrolforceand the mechanisms
inherentin the methodare discussed.
[ Work supported
by NASA Langley.]
9:30
G2.Vibrationisolafionforspaceeraft
usingthepiezoelectrie
polymerPVF2.SamuelW. Sirlin(JetPropulsion
Laboratory,Mail Stop 198-326,CaliforniaInstituteof Technology,4800 Oak Grove Drive, Pasadena,CA
91109)
Throughoutthe remainderof the currentdecadeand throughthe 1990s,the pointingrequirements
of
spaceborneacientificpayloadswill grow increasinglymore stringent.yet. for reasonsof costeffectiveness,
the
trendwill beawayfromsingle-payload-dedicated
free-flyingspacecraft
and towardlarge,multipayloadspace
vehicles.
Thebasebody
structuralfrequencies
of spacestation/space
platformswill besignificantly
lowerthan
thosefor previousmissions,
makingthe traditionalseparationbetweenpointingcontrollerbandwidthand
structuralmodesimpossibleto maintain.Man motionand machinevibrationdisturbances
will likely limit the
spacestationattitudecontrolto relativelycoarselevels.In thefaceof sucha demandingdynamicenvironment,
S13
J. Acoust.Soc. Am. Suppl. 1, Vol. 82, Fall 1987
114th Meeting:AcousticalSocietyof America
S13
futurespacestations
will hostattachedpayloads,
someof whosepointingrequirements
approachthoseof the
free-flyingspacetelescope.
Theseissuesdrivethe needfor the development
of advancedpointingmount
technology
thatcanprovidea highdegreeof precision
whilesimultaneously
isolatinga payloadfroma disturbancerich hostvehicle.A finiteelementmodelof an activesoftmount
basedon the piezoelectric
polymer
poly(vinylidenefluoride)hasbeendeveloped.
The modelincludesthe geometricnonlinearities
that are associatedwith the largedeflection
capabilityof the softmount.This modelis put togetherwith a simplespace
stationmodeland then both linear frequencydomainand time domainsimulationsare carriedout. The
wideband
disturbance
rejection
capabilities
of thedesignaredemonstrated,
bothin thefrequency
domainand
in nominaloperations.
9:55
G3. Theacousticlimit of controlof structuraldynamics.
A.H. yonFlotow(Departmentof Aeronautics
and
Astronautics,
Massachusetts
Instituteof Technology,
Cambridge,MA 02139)
The acousticlimit of activecontrolof structuraldynamicsis investigated;
the limit asthe controlbandwidthincludesa verylargenumberof naturalmodesof the structure.The pointis madethat, in thislimit,
modalanalysis
cannotprovide
reasonably
accurate
models
ofthestructural
dynamics
andthatcontroldesign
with respectto modalmodelsisthenof questionable
value.Alternativemodelingapproaches
arereviewed.A
particularwavepropagation
formalism,
applicable
to modeling
theacoustic
response
of networks
of slender
structuralmembers,
isdescribed
in somedetail.Controloptionsdesigned
withreference
to thisformalismare
reviewed,and speculations
asto futuredevelopments
of suchcontrolare offered.
10:20
G4. Activecontrolof vibrationsusingexternallyexcitedpiezoeeramie
devices.X. Q. Bao,V. K. Varadan,
and V. V. Varadan (ResearchCenter for the Engineeringof Electronicand AcousticMaterials, The
Pennsylvania
StateUniversity,UniversityPark, PA 16802)
The designandfunctionof piezoceramic
devices
containing
eitherone(unimorph)or two (bimorph)
piezoceramic
disksaredescribed.
Thefunction
ofthesedevices
istonullthetransmitted
displacement
fieldor
boththe transmitted
andreflecteddisplacement
fieldswhena displacement
or pressure
fieldis impressed
on
onesideofthedevice.Sucha devicecanbeusedto activelycontrolvibrations
of a givenfrequency
by suitably
adjustingthe voltagesthat canbe appliedto oneor boththe disks.For the unimorphdevice,fairly wideband
conditions
ofzerotransmission
canbeachieved.
Forthebimorph
device,
voltages
tothetwodisksareindependentlycontrolledsoas to achievesimultaneously
the desiredconditionsof zero reflectionand transmission.
Oneor bothvoltagesources
maydrainenergyfromthesystem.
In eachcasetheequivalent
electriccircuitcan
bemodeled
sothatthecurrent-voltage
characteristics
ofthedevicecanbecalculated
andplotted.Thepiezoceramicsarecomposite
in construction
containing
a piezoelectric
phasedispersed
in a nonpiezoelectric
phaseso
thatthedevicehastheneededmechanical
andelectromechanical
couplingcoefficients.
ContributedPapers
10:4S
G$. Active vibration control by using the wave control concept.
Jiawei Lu and Malcolm J. Crocker (Department of Mechanical
Engineering,AuburnUniversity,Auburn,AL 36849)
model
ofactive
vibration
control
isbeing
investigated
experimentally.
[Work supportedby SDIO/DNA, ContractNo. DNA-001-85-C-0183.]
A novelactivevibrationcontrolapproachusingtheconceptof wave
controlis discussed.
The idea is to try to changethe characteristics
of a
systemand to destroythe conditionof resonance
response
by addinga
controlforceat theboundaryof a vibratingsystem.The approachis differentfromthemodal-space
controltechnique,
whichisoftenusedin the
vibrationcontrolof spacestructures,
especially
whenthesestructures
are
built frommaterialswith low dampingandareveryflexibledueto their
largesize.For thedemonstration
of thisnewwavecontrolconcept,an
activevibrationcontrolmodelfor a finite lengthstringis discussed.
An
excitingforceis appliedsomewhere
on the string,and a controlforce
appliedat one end of the string is found to absorbthe vibrationalwave
propagating
to the endsothat no wavereflectionappearsat the endand
the conditionof resonance
response
is destroyed.A beammodelhasalso
beendeveloped.
The theoreticalresultsareencouraging
andbetterthan
thoseobtainedby meansof themodal-space
controlapproach.
The beam
$14
J. Acoust.
Soc.Am.Suppl.1,Vol.82,Fall1987
11:00
Gf. Active control of sound fields in elastic cylinders. C. R. Fuller
(Departmentof MechanicalEngineering,
VirginiaTech,Blacksburg,
VA
24061), R. J. Silcox,and H. C. Lester (Structural AcousticsBranch,
NASA LangleyResearchCenter,Hampton, VA 2366fi)
Much interest has recently arisen over the use of active noise and
vibrationcontrolin variousapplicationswhereweightconsiderations
are
important.The resultsof research
directedtowardsapplyingactivemethodsfor reducingnoisein the cabinsof propelleraircraftwill be reviewed.
Two differingtechniques
of implementingthe activecontrolwill be discussed.The firstconsists
of placingactiveacousticsources
in the interior
spacein order to achievecancellation.The secondmethodrelieson active
114thMeeting:
Acoustical
Society
ofAmerica
S14
control of the transmittedacousticalenergyby vibrationalforce inputs
applieddirectly to the cylinder wall. Both theoreticaland experimental
Expressions
of self and mutual impedanceof pistonsin an infinite,
rigid, plane baffleare well known. The array is coatedwith an elastic
resultsusingsimplified
modelsof aircraftfuselages
will bepresented
and
rubberskin.Plane-wave
decomposition
of thecompression
andshearpo-
the mechanisms inherent in the control action will be outlined.
11:15
G7. Interacfiooimpedanceof a systemof pistonscoatedwith an elastic
skin usinga plane-wavedecomposition.
Philippe Boissinot(ThomsonSintraA.S.M., ROutedesDolines,Parc d'activit•sde Valbonne,B.P. 38,
for the nearfieldpressureand for the displacementfield in the sitin.This
pressureis then integratedover the pistonsto obtain expressions
of self
andmutualradiationimpedance,
whichis referredto asaveragesurface
velocity.Resultsare presentedfor linear (2-D case)and circular (3-D
case)radiatorsin termsof kd (dimensionless
productof thewavenumber
and the distancebetweenpistons).The other parametersare thickness
andelasticcharacteristics
of theskinandthedimension
of thepiston.Asa
postprocessing,
thethree-dimensional
directivitydiagramfor thewhole
arraycanbeeasilyobtainedthroughtheplane-wave
decomposition
in the
fluid.
06561 Valbonnc Cedex, France)
TUESDAY MORNING, 17 NOVEMBER 1987
UM AUDITORIUM
LOBBY AND PREFUNCTION
AREA, 9:30 A.M. TO 12:00 NOON
SessionH. SpeechCommunicationh Production(PosterSession}
Betty H. Tuller, Chairman
Centerfor ComplexSystems,
FloridaAtlanticUniversity,
BocaRaton,Florida33431
All posters
willbedisplayed
from9:30a.m.to 12:00noon.To allowcontributors
theopportunity
toseeother
posters,
contributors
ofodd-numbered
papers
willbeattheirposters
from9:30to 10:45a.m.andcontributors
of even-numbered
paperswill beat theirposters
from 10:45a.m.to 12:00noon.
ContributedPapers
HI. Word-based versus syllable-basedmodels of speech production
planning:Evidencefromelicitedphonological
errors.StcfanieShattuckHufnagcl(Re,arch Laboratoryof Electronics,
Massachusetts
Institute
of Technology,Cambridge,MA 02139)
Earliererror-clicitation
experiments
haveshownthat single-segment
errorsarc morelikely to be elicitedwhenthe targetsegments
sharepositionin thewordonset,andlesslikelywhenthetargetsegments
crossword
position(e.g.,/p/and/f/are morelikelyto interactin "paradefad"and
lesslikelyin "repeatfad,"eventhoughbothtargetsegments
arein prestress
positionin thelattercase).A separate
seriesof experiments
using
CVC stimuli showeda differencein error patternswhen the stimulus
wordsarespokenin listsversus
embedded
in shortphrases;
stimulilike
"leapnotenaplute"elicitaboutthesameproportion
of errorsin initial
andfinalposition,
whilethephrasalversion("From theleapof thenoteto
thenapof thelute") elicitsfar fewererrorsin finalposition.
If thisdifference betweenword lists and phrasesextendsto other aspectsof error
patterns,it might affectthe word-position/stress-position
resultsfor
mixedone-and two-syllablestimuli.However,resultsshowthat, when
thesestimuliareembedded
in phrases,
theerrorpatternsremainremarkably similar.Moreover,whenspeakersare askedto generatesentences
usingthewordsof the stimulus,insteadof readingor recitingthe phrases
providedby theexperimenter,
resultsagainsupporttheclaimthat wordonsetconsonants
aremorelikely to interactin an errorthanareprestress
consonants.
Thesefindings
suggest
thatwordstructureplaysa rolein the
production
processing
representation
thatisinforcewhensingle-segment
errors
occur.
Speech
production
involves
theformationandrelease
of constrictions
at differentpointsin thevocaltract.Progress
isreportedona task-dynamic computational
modelof autonomous
coordinationamongthe:componentsof articulatorysynergies
(e.g.,lipsandjaw) that participal:e
in motionsalongfunctionallydefinedtract variables(e.g., lip apertureand
protrusion).For eachspeech
gesture,
a time-invariant
dynamicalsystem
(damped,second-order)
is specifiedat the tract-variablelevel,and is
transformed
intoa yesrurallyandposturallyspecific
dynamicalsystemfor
thesynergycomponents.
Articulatorymovement
patternsemergeasimplicit consequences
of the gesture-specific
tract-variablecontrolstructuresandtheongoing
posturalstateofthearticulators.
Explicittrajectory
planningis not required.Significantly,the modeledcoordinadveprocesses
are exactlythe sameduringsimulations
of unperturbed,
mechanicallyperturbed,
andcoproduced
speech
gestures.
All simulations
areimplementedusing the Haskins Laboratoriessoftware articulatory
synthesizer,
and are restrictedto the vocaltract'ssagittalplane,and the
simplifiedarticulatorygeometryrepresented
in the synthesizer.[Work
supported
by NIH GrantNS-13617andNSF GrantBNS-85-20709.
]
H3. Source models for fricative consonants.Christine H. Shadle
(Department
of Electronics
and ComputerScience,
Universityof
Southampton,
Southampton
SO95NH, England)
Source
parameters
for models
of fricativeconsonants
werederived
fromexperiments
usingmechanical
models
having
theprofileofmidsagittal x raysgivenin Fant [Acoustic
Theory
ofSpeech
Production
(Mouton,
The Hague,1970)]. By positioning
a pressure
probeat severalpoints
alongthewallof eachmodel'stract,it wasshownthatsound-generation
H2. Task-dynamicmodelingof interarticulatorcoordination.Elliot
characteristics
of fricatives
suchas/s, .•/ differfundamentally
fromthose
L. Saltzman, Philip E. Rubin, LouisGoldstein, and Catherine
ofq,x/withregard
to source
location,
source
spectrum
levela•:lowfre-
P. Browman (Haskins Laboratories,270 Crown Street,New Haven, CT
quencies,
andtherelationship
between
source
spectrum
amplitude
and
meanvolumevelocity.In bothcases,
soundisgenerated
whenturbolent
06511)
$15
J.Acoust.
Soc.Am.Suppl.
1,Vol.82,Fall1987
114thMeeting:
Acoustical
Society
ofAmerica
Sl 5
air strikesrelativelyrigid boundaries.The angleof the boundarywith
respect
totheflowofair isthesignificant
factorin thiscase.For/s, J'/, the
obstacleis at fight angles,for/•, x/, the "obstacle,"the tract wall, is
nearlyparallelto the flow. Implicationsfor vocaltract modelswill be
discussed.[Work supportedby a Hunt Fellowshipawarded by the
AcousticalSociety,and a grant awardedby the North Atlantic Treaty
Organizationin 1984.]
H7, Voicing distinction for fricatives: Acoustic theory and
measurements.Kenneth N. Stevens (Department of Electrical
Engineeringand ComputerScienceand the ResearchLaboratoryof
Electronics, Speech Communication, Massachusetts Institute of
Technology,
Cambridge,
MA02139),SheilaE. Blumstein
(Department
of CognitiveandLinguisticSciences,
BrownUniversity,Providence,
RI
02912), andLauraB. Glicksman(ResearchLaboratoryof Electronics,
Speech Communication,Massachusetts
Institute of Technology,
Cambridge,MA 02139)
H4. A twisting one-mass gloRal model. Lloyd Rice (Phonetics
Laboratory,UCLA, Los Angeles,CA 90024-1543)
A newmodelof vocalcordvibrationwill bepresented
thatrepresents
thecordbodyby a singlemassexhibitingoscillatory
behavioron a horizontalaxistogetherwitha rotationalcomponent.
Themodelisadequate
to describethe divergingand convergingconfigurations
of the glottal
openingasobserved
at differentphases
of theglottalcycle.Characteristics
of the modelare exploredundervariousglottalvibratorymodesand are
comparedwith thoseof existingmodelssuchas the populartwo-mass
configuration.
Theoreticalanalysissuggests
that simultaneous
generationof vocalfoldvibrationandturbulencenoiseat a supraglottal
constrictionrequires
rather preciseadjustmentof the structurescontrollingthe glottis,the
intraoral volume, and the supraglottalconstriction.The theory shows
thattheretendsto bea reciprocalrelationbetweenvoicingamplitudeand
theamplitudeof theturbulence
noise.It is notsurprising,
therefore,that
vocal-foldvibrationdoesnot alwaysoccur throughoutthe constricted
interval when a "voiced"fricativeis produced,and that variationin the
noiseamplitudeisoftenobserved.
Measurements
of theamplitudeof voicing (expressed
as the spectrumamplitudein the regionof the first harmonic) and of frication noisehave beenmade for severalfricative conson-
antsspokenby severalspeakersin a numberof phoneticenvironments,
includingutterancefinal and intervocalicposition,and in clusterswith
othervoicedandvoiceless
fricatives.Evidencefor voicingcanusuallybe
foundoversomeportionof the constricted
interval,particularlyin the
vicinityof fricativeonsetor release.However,voicingmay be weakor
absentwhen the voicedfricativeis followedin a clusterby a voiceless
fricative. [Work supportedin part by Grants NS-04332and NS-15123
from the National Institutesof Health. ]
HS. Bending-beam
model of vocal-foldvibration. Cotinc Biekley
(Departmentof Electrical Engineeringand ComputerScienceand
Research Laboratory of Electronics, Room 36-521, Massachusetts
Instituteof Technology,Cambridge,MA 02139} and Kevin Brown
(Departmentof MechanicalEngineering,Massachusetts
Institute of
Technology,
Cambridge,
MA 02139)
HS. Stresseffectson stopconsonant
closureandreleasegestures.
Mark
K. Tiede (Haskins Laboratories,270 Crown Street,New Haven, CT
06510)
Recenttheoreticaldevelopments
haveshownthat a modelbasedon
the theoryof bendingbeamsis the bestpredictorof the fundamental
frequencies
of youngchildren's
speech
[Bickley,
Proc.11th Int. Congr.
Phon.Sci.(1987)]. For childrenof age3 yearsandyounger,thevalues
predictedby a spring-mass
modelare too low, and the valuesof a vibrat-
ing-string
modelaretoohigh.In thecurrentstudy,theeffectofgrowthof
thevocal-fold
structureonfundamental
frequency
isanalyzed.Thevocalfoldstructure
growsnonuniformly;
forexample,
a l-year-old's
vocalfolds
areapproximately
one-fifthaslongasanadult'sfoldsbutonly 10% thinner.The bending-beam
modelis an improvement
overothermodelsbe-
Thisstudyseeks
to characterize
thearticulatory
kinematics
of stop
consonant
gestures
incontrasting
environments,
withtheaimofincorporatingtheresults
intothegesture-based
approach
tosynthesis
underdevelopmentat Haskins.
TheCVCVCtokens
drawnfromtheBellx-raymicrobeamcorpushavebeenexamined,representing
combinations
of stress,
vowel,andconsonant
typespokenin isolationby a femalespeaker
of
English.
Measurements
weretakenfrompeaks
oftheverticalcomponent
of pelletdisplacement
andvelocitycorresponding
to consonant
closure
andrelease
gestures,
usingthelowerlip pelletforlabialsandthetongue
causeit reflectsthe structure of the vocal folds and the attachments of the
root pelletfor velars.The ANOVA resultsshowthat stressaffectsconso-
vocal-foldtissueto the arytenoidand thyroidcartilages,
characteristic•
nantgesturedurationindependently
of coproduced
voweltype,butinter-
previously
ignored.
Thefundamental
frequency
ofthenewmodeldepends
onboththebeamlike
characteristics
of thevocalfoldsandthespringiness
of thestructure.Changes
in fundamental
frequency
arepredicted
from
actssignificantly
withconsonant
type,possibly
because
velarscompete
the modelasa functionof age.
with coproducedvowelsfor controlof the tongue.Resultsalsoshowed
different
results
forconsonant
duration
depending
onwhether
thegesture
occurredin thefirstor finalsyllable,whichis consistent
with previous
studiesof prepausallengthening[D. H. Klatt, J. Phonet.3, 129-140
(1975) ]. [Work supportedby NSF Grant BNS-8520709.]
H6. Estimating vocal tract shapes from x-ray microbeam data.
Peter Ladefoged and Mona Lindau-Webb (Phonetics Laboratory,
UCLA, LosAngeles,CA 90024-1543)
X-ray microbeamtechniquesprovide data on a few points on the
tongue.The possibilityof an algorithmthat will turn thesedatainto a full
specification
of thewholetongueshapeistested.A weakness
of thesystem
isthatit isdifficultto placepelletsontheposteriorhalfofthetongue.The
firstgoalis thusto investigate
what is the minimumnumberof pellets
necessary
to predicttheshapeof theanteriorpartof thetongue.Data were
recordedfromsevenpoints,fourof whichwereonthefrontof thetongue,
approximately15mm apart.The subjectproducedshortutterancesillustratingEnglishvowels.This procedurewasthenrepeatedwith the four
tonguepelletsmovedapproximately5 mm forward.Imagescansof sus-
tainedEnglishvowelsin which the subjecthad a chainon the tongue
midlineconsisting
of 17pellets5 mm apartwerealsorecorded.The results
alloweddetermination
of theextentto whichtongueshapes
canbedeterminedfrom x-ray microbeampellets.[ Work supportedby NIH. ]
$16
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
H9. Interactionof speaking
rateandpostvocalic
consonantal
voicingon
voweldurationin AmericanEnglish.H. S. Gopal (Calllet Center,
UniversityofTexasat Dallas,1966InwoodRoad,Dallas,TX 75235) and
Ann K. Syrdal (AT&T Bell Labs, IH6C-320, Naperville-Wheaton
Road, Naperville, IL 60566)
Voweldurationisinfluenced
bothbyspeaking
rateandbyvoicing
of
the postvocalic
consonant.
Our studysystematically
investigates
how
thesetwofactorsinteract.Syllableandsegment
durations
weremeasured
for/pVC/target syllables
containing
oneof eightvowelsandvoicedor
voiceless
stopsor fricatives.
Targetsyllables
wereproduced
in sentence
contextsat three speakingratesby four femaleand three male native
AmericanEnglishspeakers.
Our findingsreplicateand extendKlatt's
incompressibility
modelof vowelduration[D. H. Klatt, J. Acoust.Soe.
Am. 54, 1102-1104( 1973) ]. The two factorsinfluencingvowelduration
do not combineindependentlyin a multiplicativeor additivefashion.
Instead, they interact such that vowels manifesta resistanceto further
shortening.
114thMeeting:Acoustical
Societyof America
S16
HlO. Token-to-token
variat'onof tengue-body
voweltargets:Theeffect
ofenarficulation.
J. S. PerkellandM. H. Cohen(Research
Laboratory
of Electronics,
Room36-543,M•ehusetts Institute
of Technology,
Cambridge,MA 02139)
Variation
ofvoweltargets
fora midsagittal
pointonthetongue
body
ofa single
speaker
ofAmerican
English
wasexamined.
Thesubject
pronouncedmultiple repetitionsof nonsenseutterancesof the form
foV(C)Vbn/, in whichthe vowelswere/i/,/u/,/a/and
theconsonant,
whenpresent,
wasfa/or/h/.
Stress
wasplacedon thesecond
syllable.
Movements
of a singlepointonthemiddleof thetongue-body
dotsum
weretransduced
with a newalternatingmagneticfieldmovementtransducersystem.For eachvowel,a scatterplotwasgenerated
of "target"
positions
(x,.Vcoordinates
} at themomentof minimumtangentialvelocity. In general,thesescatterplotsareelongated.
Whenthevowelsin the
firstandsecond
syllables
are the same,the scatterin targetpositionis
relativelytighterand lesselongated
thanwhenthevowelsare different.
Whenthevowelsin thetwosyllables
aredifferent,thelongaxispassing
throughthescatterforonevowelisorientedin thedirectionof thetarget
for the othervowel,providinga "statistically
based"demonstration
of
contextdependence
of articulatorytargets.[Work supportedby NIH
Grant No. NS04332.]
HI3. Stresseffectson relic gestures.
RenaArens Krakow (Haskins
Laboratories,
270CrownStreet,New Haven,CT 06511)
In his cross-language
surveyof oral and nasalvowelpatterns,
Schourup
[Work.Pap.Linguist.
lS, 190-221(1973)] reported
thatcontextualvowelnasalization
ismorelikelytooccurinstressed
syllables
than
inunstressed
syllables.
Thisstudy
looks
athowspatial
andtemporal
patternsof relicmovement
areaffected
bystress
andfindsartieulatory
evidencein supportof Schourup's
claim.Verticalmovements
of the velum
were
monitored
whilethe(American
En$1ish)
speaker
p?oduced
utterances
withdifferent
stress
patterns
(mVbVbvsmVbVb;
b'•/bVm
vs
bVb•rm).
Velic
height
measured
atthemidpoint
ofthevowels
adjacent
to
the nasal consonantswas significantlylower when the vowelswere
stressed.
Thispattern,however,
primarilyreflected
temporaldifferences
intherelicgestures
duetostress
ratherthanchanges
inthespatial
extent
ofyellolowering
forthenasalconsonants.
Asanexample,
thevelicloweringgestures
fortheinitial/m/in/m:ibab/and/mab:ib/appeared
quite
similarbothin theirtimingandspatialextent,butrelicraisingfromthe
low positionwasinitiatedconsiderablylater in/m•bab/than/mab•b/.
Thesefindingsindicatethatpartof thearticulatory
distinction
between
syllables
with differentlevelsof stressis the temporalpatternof velic
movement.
[Worksupported
by NIH GrantsNS-13617andHD-1994.]
HI4.
Hll. Fundamentalfrequency and intensity control in speech.
Helmet Strik and LouisBores (Institute of Phonetics,Nijmegen
University,P.O. Box9103,6500HD Nijmegen,The Netherlands)
A gradualdowndriftof fundamentalfrequency(F0) and intensity
(IL) d.uringspeech
utterances
hasbeenobserved
in almostall languages.
Because
bothF0 andIL arerelated
tosubglottal
pressure
(P,•) andbecause
P• issupposed
rodecrease
astheairsupplyin
thelungs
decreases,
it
hasbeenhypothesized
that th/sdowndrift,usuallycalleddeclination,isa
passiveprocess.In utteranceswheredeclinationis absent,like in some
typesof questions,
activecountermeasures
wouldthenbe necessary.
In
thisresearch,
P•, airflow,electrogiottogram,
speech
signal,andEMG
activityof the cricothyroid,sternohyoid,and vocalismuscleshave been
recorded,whilelinguistically
naivesubjects
sustained
vowelsona fixedF0
and IL and produceda numberof sentences
with differentintonation
patterns.
Resultsindicatethatthereisnodirectrelationbetween
air sup-
Generating intonational support for
discourse. James
RaymondDavis(AT&T Bell Laboratories,
Murray Hill, NJ 07974and
Massachusetts
Instituteof Technology,Media TechnologyLaboratory,
Cambridge,MA 02139)
Properintonationcan make a spokenmessage
more intelligibleby
markinginformationasold or newandcommunicating
the hierarchical
structureof information.Use of intonationalvariationis especiallyfeasible in a systemthat synthesizes
speechfrom an abstractrepresentation
(insteadof from text} because
the programalreadyknowsthestructureof
the informationto beconveyed.This paperpresentsa schemafor assigningpitchrangeandchoosing
pitchaccents.The schemadrawsuponwork
on discourselB. J. Grosz and C. L. Sidncr,Cornput.Linguist.12, 175204 (1986)] andon intonationalmeaning[J. Hirschberg
andJ. Pierrehumbert,Proc.24thMeet.Assoc.Cornput.Ling.,136-144(1986) ]. The
modelhasbeentestedwith a programwhichgenerates
spokendirections
for drivingin Cambridge[J. Davis,Proc.Am. VoiceI/O Soc.(1986)].
plyinthelungs
andP•, andthatP•, F0, andIL canbekeptonadesired
levelwithoutactiveinvolvementof the musclesystemsthat controlinto-
nationin speech.
[Research
supported
bytheFoundagion
of Linguistics,
fundedby Z. W. O. ]
HIS. Evaluationof speechunderstressand emotionalconditions,John
H.L. HansenandMark A. Clements(Schoolof ElectricalEngineering,
GeorgiaInstituteof Technology,Atlanta,GA 30332)
This paperpresents
resultsfrom an investigation
of how stressand
HI2. Respiratoryrespunseto !o• of velar resistunce.Kathleen E. Mort,
Anne H. B. Putnam, and Donald W. Warren (Dental ResearchCenter,
Universityof North Carolina,ChapelHill, NC 27514)
The hypothesis
that speech
aerodynamics
conformsto theprinciples
of a regulating
systemwastestedin ninenormaladultsubjects.
The velar
mechanism
wasperturbed
byhavingsubjects
lowerthesoftpalateduring
a seriesof wordsinvolvingplosiveconsonants.
The pressure-flow
techniquewasusedto measureoral pressures
and velarresistance.
Inductive
emotion
affectspeech
characteristics
withspecific
application
to•mprovingautomatic
speech
recognition.
Paststudies
havebeenlimitedinscope,
oftenusingonlyoneortwosubjects
andanalyzing
onlyoneortwoparameters(typicallyinvolvingpitch). A comprehensive
speech
understress
database
hasbeenestablished
at GeorgiaTechfor thepurposes
uf stress
research.
Thedatabase
ispartitioned
intofivedomains,
encompassing
a
widevarietyofstresses
thatinclude:
various
talkingstyles( slow,fast,soft,
loud,angry,clear,question,
in noise
}, single
anddualtracking
workload
plethysmography
wasusedto measuretidal volumesassociated
with test
stress
inducingtasks,emotionalspeech
frompsychiatric
analysis
session,
andsubjectmotion-fear
tasks.A totalof 32 speakers
wasemployedto
consonants.
Thedataindicatethatintraoralpressure
remained
at appro-
generate
inexcess
of i 6 000utterances.
Thedatabase
evaluation
waspar-
priatelevels( > 4.0 cm H20) after lossof velar resistance.
Tidal volume
titionedintothreeareas.Analysis
wasfirstperformed
on (i) speech
with
simulatedstress
and ( ii) speech
from stress
inducingwarkloadtasksor
speech
in noise.Statistically
significant
parameters
wereestablished,
and
an equivalent
analysis
wascarriedout over(iii) speech
produced
under
didnotchange
duringinspiration
butincreased
duringspeech
expiration.
The difference
wasstatistically
significant
(p < 0.01). Theseresultssupportpreviousfindingsof Warren [Cleft PalateJ. 23, 251-260 ( 1986}] in
cleftsubjects,
Putnamet al. [J. SpeechHear. Res.29, 37-49 (1986) ] in
perturbationstudies,and Warren et al. [L Acoust.Soc.Am. 67, 18281831 (1980), Folia Phoniatr. 33, 380-393 (1981 }, Folia Pboniatr. 36,
164-173(1984)] in biteblockstudiesthat intraoralpressures
aremain•
tainedat appropriatelevelsin thepresence
of loweredairwayresistance.
It
is concludedthat, underthe testconditions,
pressure
wasregulatedby
controllingrespiratory
effort.Thiscompensatory
response
increased
airflowrateandvolumewhenresistance
fell. [Work supported
by NIDR.]
S1?
J. Acoust.Soc.Am.Suppl.1, VoL82, Fall1987
actualstressand emotion.This schemewas chosensincesimulated condi-
tionsallowedfor carefulcontrolof vocabulary,
taskrequirements,
and
backgroundnoisecharacteristics.Evaluation over actual stressor emotional conditionswas usedto verify resultsestablishedunder simulated
conditions.
Variables
employed
in theevaluation
include:
pitch(mean,
variance,highermoments,
pointprocess
characterization},
glottalwave-
formcharacteristics,
glottalsource
spectrum
(spectral
tilt, energyconcentration),duration,intensity,formantlocationsand bandwidths,vo-
114thMeeting:Acoustical
Societyof America
S17
cal-tractshapingbasedon line spectralpair coefficients,
and the
variability
ofeachofthese.
Resulting
categorizafious
willbepresented,
as
wellasthestatistical
significance
ofcachsetofmeasurements.
[Research
supported
byU.S. ArmyHumanEngineering
Labs.]
H16.
The control of voice onset time and vowel duration after
parancoplastiecerebellar degeneration:An acousticstudy. Susan
J. Behrens, Nell Anderson, Jerome Posner, and John J. Sidtis
(Department
of Neurology,
MemorialSloan-Kettering
CancerCenter,
1275 York Avenue, New York, NY 10021)
Speech
production
wasexamined
in a groupof sixsubjects
withparaneoplastic
cerebellar
degeneration,
a neurological
disorder
thatproduces
severe
dysarthria.
Subjects
wererecorded
repeating
CVC andCVCV syllablesthatincluded
thestopconsonant
[p b t d k g] andthevowels[i a u].
methodcalculates
a noise-to-signal
(N/S) ratio,definedfromthepower
spectrum,whichindicatesthe depthof valleysbetweenthe harmonic
peaks.A discreteFouriertransformbasedon a continuously
variable
windowspanning
exactlyfour fundamental
periodsis usedto calculate
thespectrum.
A two-stage
procedure
isusedto determine
theexactdurationof thefourfundamentalperiods.An initialestimateisobtainedusing
autocorrelation
in thetimedomain.A morepreciseestimateisobtainedin
thefrequencydomainby minimizingtheerrorsbetweentheDFT andthe
predictedspectrumof a windowedharmonicsignal.Analysisof synthesizedvoicesshowsthat the N/S ratio is sensitiveto additivenoise,jitter,
and shimmer, and is insensitiveto slower (8 Hz) modulation in fundamentalfrequencyand amplitude.An analysisof pre- and post-operative
runningspeech
of sixpatientswithlaryngealpolypsor noduleshasconsistentlyindicatedthe successful
therapeuticresultsfor all subjects.[Work
supported
by NIH Grant NS-13870.]
Voweldurationspreceding
voicedandvoiceless
segments
andvoiceonset
time (VOT) were measured.The vowel duration measuresassessed
the
HI9.
preservation
of intrinsicdurationproperties,
andthevariationof these
properties
in conditioning
phonological
contexts.
The VOT measure
as-
dysarthric speakers. Helen Southwood and Gary Weisruer
(Departmentof Communicative
Disorders,
Universityof Wisconsin--
sessed
the coordination
of two independent
articulatoryevents.Results
indicatedthat thecerebellarsubjects
normallydifferentiated
amongindividualvowels,and alteredvoweldurationas a functionof phonological
Madison. Madison, WI 53706)
context.In contrast,they tendedto reduceVOT for voicelesssegments,
and,in thecaseof themostimpairedsubject,thevoiceless
segments
were
alwaysperceived
asbeingvoiced.AlthoughtheVOT durationswerereduced,therewasnooverlapbetweenvoicedandvoiceless
VOTs for most
cerebellarsubjects.
Theseresultssuggest
that the temporalcoordination
of articulatorymaneuversrather than generaltiming of segmentaldura-
tion may specificallyinvolve the cerebellum.[Work supportedby
NS 17778.]
Fundamental frequency contours produced by normal and
Perceptual
descriptions
of dysarthric
speech
oftenincludetermsthat
are meantto indexaberrancyin sentence-level
fundamentalfrequency
(F0) contours.Whereasthereisgeneralagreement
that manydysarthric
speakers
produce"abnormal"F0 contours,two relevantissues
that appearto be unanswered
are: ( ! ) How should"normal"F0 contoursbe
characterized,and (2) what is the natureof F0 contoursproducedby
dysarthricspeakers.
In thepresentpaper,a reportismadeon a category
approach
to identifying
rangesof normalF0 production
in youngadults
andgeriatrics,
andthenF0 contours
ofspeakers
withhypokinetic
(dueto
Parkinson's
disease
) andspastic(congenital)dysarthriaareshown.Discussion
will focuson thesuccess
of the categorysystem,and the motor
controlimplications
of thedysarfixric
F0 contours.
[Worksupported
by
NIH.]
HI7.
The
control
of voice onset time
and vowel duration
after
paraneoplusticcerebe!lar degeneration:Correlation with regional
cerebral glucosemetabolismusingpositronemissiontomngraphy.John
J. Sidtis, SusanJ. Behrens,James R. Moeiler, StephenC. Strother,
Nell Anderson, Jerome Posner, and David
A. Rottenberg
(Department of Neurology,Memorial Sloan-KctteringCancer Center,
New York, NY 10021)
In a companionreport, an impairmentin voiceonset'time(VOT)
controlwasdescribed
for a groupof subjects
with paraneoplastic
cerebellar degenerationwhocouldotherwiseproduceappropriatesegmentalduration. The underlyingneurophysiological
changeswere related to regionalcerebralmetabolicratesfor glucose(rCMRGIu) deterrainedby
FlS-fiuorodenxyglucose/positron
emissiontomography(PET). Nine
cerebellarsubjectsand 18normalcontrolswerestudiedwith eyespatched
whilelisteningto musicandperiodicverbalbriefings.
The rCMRGIu was
calculated
for eachof 28 anatomically
definedregionsof interest(ROI).
The cerebellarsubjects
couldbedifferentiated
fromnormalsby theirlower globalmetabolicrate,andby theirrCMRGIu pattern.For thosecerebellar subjectswho could participatein the acousticstudy,cerebellar
rCMRGlu wassignificantly
belownormalrange(p < 0.05) in all but one
case.Severityof VOT abnormalityappearedto be relatednot only to
cerebellarrCMRGlu, but to abnormallylow corticalrCMRGlu as well.
The roleof thecerebellumin maintainingtemporalcoordinationof articulatorymaneuvers
appearsto involvethe coordination
of corticaland
subcorticalbrain regions.[Work supportedby NS17778and NS23473.]
H20.
Acoustic phonetic features of young children's potential
homophones.
George D. Allen, Diane Frome Loeb, Lori Swanson,
Laurence B. Leonard, and Richard G. Schwartz (Department of
AudiologyandSpeechSciences,
PurdueUniversity,WestLafayette,IN
47907 )
Homophones
are differentwordsthat soundalike,e.g.,"bear"and
"bare." Sinceyoungchildrencan often hear differences
they cannot
speak,theymayproduce
homophones
forwordstheyknowto bedifferent.Thus,forexample,a childmayhearthat"bike"and"bite"aredifferent,butifs/he cannotyetproduce
word-final
consonants,
s/hemayutter
bothas/hal/. Two questions
presentlyunderinvestigation
are: ( 1) Do
youngchildrenactivelyseekto includeor excludesuchpotentialhomophonesin theirearlyvocabulary?
(2) Do childrenfacedwithsuchpotentialhomophones
producesubtle,subphoncmic
differences
between
them?
Thispaperreports
theresults
ofa studyaimedatanswering
thesecond
of
thesetwoquestions.
Nine20-month-old
normallydeveloping,
Englishspeaking
children's
utterances
weretaperecorded
for acoustic
analysis.
Theseutterances
wereproduced
in situations
in whichhomophones
were
likelyto resultfrom (a) reductionofinitial consonant
clusters,(b) stop-
pingofinitialfricatives,
or (c) deletion
offinalconsonants.
Althoughit is
hypothesized
thatthemostlikelysources
of subphonemic
differentiation
wouldbeVOT [fortype(a) and(b) pairs]andvowelduration[fortype
(c) ], F0 andformantfrequencies
werealsomeasured
anddetailedaudi-
toryphonetic
analyses
wereperformed.
Results
fromtheseanalyses
will
bediscussed
in termsof individualandgrouppatternsof differentiation
between
potentially
homophonous
wordpairs.[Worksupported,
in part,
HI8.
Acoustic analysis of hoarse voices in running speech.
Hiroshi Muta. Thomas Baer (Haskins Laboratories, 270 Crown Street,
by NIH.]
New Haven, CT 06511), and Hiroyuki Fukuda (Department of
Otolaryngology,
KeioUniversitySchoolof Medicine,35 Shinanomachi,
Tokyo 160,Japan)
A methodof pitch-synchronous
acousticanalysisof hoarseness
requiringa voicesampleofonlyfourfundamental
periodsispresented.
This
S18
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
H21. Cycle to cycle spectralperturbationsin the voicesof female
speakers.A. Yonovitz and L. Yonovitz (Speech,Languageand
LearningCenter,12841JonesRoad,Houston,TX 77070)
114thMeeting:
Acoustical
Societyof America
S18
The glottalfunctionwasobtainedthroughtheuseof a reflectionless
tube.This tubeactedas a pseudoinfinite
terminationof the vocaltract.
BellLaboratories,
Room2D-452,600 MountainAvenue,Murray Hill,
Tenfemalespeakers
phonat•la neutralvowelwhiletargetmatching
toa
210-Hztone.Theglottalwaveform
wasdigitizedandeachcyclewaspartirionedat zerocrossings.
Thisprocedure
provided
anaccurate
determinationoftheperiodandseparate
timingmeasures
forthepositive
andnega-
In English,the alignmentof intonationpeakswith their syllablesexhibitsa greatdealofoontcxtuallygovernedvariation.Understanding
this
tive portionsof the glottal pulse.DiscreteFourier analysison each
individualcycle indicatedchangesin the spectralcontent.The data
showeda systematic
changein the spectralparameters
relatedto the
open-close
ratiofor eachcycle.Spectral
perturbation
analysis
maybea
moreinclusivemeasure
of waveshape
changes
thanjitter or shimmer.
NJ 07974)
variation
isof theoretical
interest,
andmodeling
it correctly
isimportant
forgoodqualityintonationsynthesis.
An experimental
studyof thealignment of prenuelearaccentpeakswith their associated
syllableswill be
described.
Two speakers
producedrepetitions
of namesof theform"Ma
Lemm," "Morn LeMann," "Mamalie Lemonick," and "Mama Lemonick," with all combinationsof the four first names and three surnames.
Segmental
durationsandtheF0 peaklocationin thefirstnameweremeasured.Resultsshowthat althoughbothspeakingrate and prosodieoontextaffectsyllableduration,theyexertdifferentinflueaces
onpeakalign-
ment.Specifically,
whena syllableis lengthened
by a word boundary
(e.g.,Ma Le Man versusMamaLetore)or stress
clash(e.g.,Ma Lemm),
H22. The timing of prenuclearhigh accentsin English. Kim E.
A. Silverman (AT&T Bell Laboratories,Room 2C-440, 600 Mountain
Avenue,Murray Hill, NJ 07974) and JanetB. Pierrehumbert(AT&T
S19
J. Acoust.
Soc.Am.Suppl.1,Vol.82, Fall1987
the peakfalls disproportionately
earlierin the vowel.TMs seemsto be
relatedto the syllable-internal
durationalpatterns.It is concludedthat
rulesfor generatingphoneticdetailsfrom phonologicalstructuremust
access
informationaboutthe upcomingprosodiccontext.
114thMeeting:
Acoustical
Societyof America
TUESDAY
AFTERNOON,
17 NOVEMBER
1987
TUTTLE
CENTER ROOM, 1:00 TO 3:35 P.M.
SessionI. Physical AcousticsII: Ultrasonics and Physical Effects of Sound
Yves H. Berthelot, Chairman
Schoolof MechanicalEngineering,GeorgiaInstituteof Technology,
Atlanta, Georgia30332
Chairman's
Introductionwl:00
ContributedPapers
1:05
II.
Some experiments in ultrasonic pulse shaping. D. Kent Lcwis
(LawrenceLivermoreNational Laboratory,NDE Section,Livermore,
CA 94950)andBill D. Cook(Universityof Houston,CullenCollegeof
Engineering,Houston,TX 77004)
Considera pulse/echoultrasonicsystemwherethe ultrasoundis re-
flectedfroma largeparallelreflector.Controlof theshapeof theoutput
electricalsignalout of thissystemis attemptedby shapingtheelectronic
pulseinitiallyappliedto a transducer.Analysisshowsthat transduction,
both generationand reception,and propagationeachinvolvedifferentiation.Insteadof havingthegoalto bca unipolarpulse,thedesiredwave-
fibrouscompositeplatesis presented.The platesare supposedto be immersedin waterandsubjected
to incidentwavesat arbitraryanglesfrom
the normals.For the singlelaminateplate, solutionsare presentedfor
arbitraryazimuthalangles.However,for the generalmultilayeredplate
case,treatmentis restrictedto the casewherethe waveis incidentalong
planesof symmetryof eachindividuallamina.Reflectionand transmission coefficientsare derived, from which characteristicbehavior is identi-
fied.Comparisons
betweentheoryandexperiments
in the formof reflected energydistributionand identificationof dispersion
basedupona total
transmission
criterionare given.
form has been chosen to bca third derivative of a Gaussian function.
Initially,a Gaussian-shaped
pulseis sentinto thesystem,andit isdeterminedby signalprocessing,
whatmodifications
of thedrivingwaveform
areto bcmade,and then thisnewlyshapedpulseissentto the transducer.
The outputisthenverycloseto our desiredthird derivativeof a Gaussian.
Integrationof the outputsignalthreetimesyieldsa unipolarpulseof
Gaussianshapewith very small kurtosis.
1:50
14. Measurementsof ultrasonicparametersin fluid-filledI•orousmetals
with different grain size. Laszlo Adler, Qiang Xue (Department of
WeldingEngineering,The Ohio StateUniversity,Columbus,OH 43210},
Alain Jungroan,
andGerard Quentin(GroupedePhysique
desSolides,
Universitc Paris 7, Paris, France)
1:20
I2. Applicationof acousto-optic
light modulationto the lasergeneration
of ultrasound. $acek $arzynski and Yves H. Berthelot (School of
MechanicalEngineering,
GeorgiaInstituteof Technology,
Atlanta,GA
30332}
Whena laserbeampasses
throughan acousto-optic
Braggmodulator
operatedat constantfrequency,one observes
the splittingof the laser
beamintoseveraldirections
at anglesproportional
to theinputfrequency
of theBraggcell.Consequently,
scanningof a laserbeamcanbeachieved
Ultrasonic
wavepropagation
in sintered
metallicsamples
(immersed
in fluid) wasinvestigated.
Samples
madeoutofbronzeandoutofstainless
steelmaterialswithparticlesizesrangingfrom30--600pwereusedin this
study.In orderto correlateparticlesizewith ultrasonicparameters,
all
sampleswerechosenwith approximately
the samevolumeporosityof
30%. Fast and slowcompressional
waves,surfacewavevelocities,aswell
as attenuation,were measured.The frequencydependence
behaviorof
theseultrasonicparameters
wasstudiedfrom 1-20 MHz andcorrelatedto
particlesize.[Thisworkwassupported
byNATO Grant0131/87 andby
the NationalScienceFoundationGrant INT-8614592.]
purely
electronically
byapplying
anFM chirped
signal
toa Bragg
modulator.A scanning
rateof about4 mm//•s hasbeenobserved
at a distanceof
3 m from a Braggcell modulatedbetween35 and 40 MHz in a 4-ps
intervalwith a I-W cw argon-ionlasersource.Sucha scanningtechnique
can be usedto enhancethe thermalgenerationof ultrasonicwavesin a
sampleilluminated with a laser beam by scanningthe laser beam at a
velocitythat matchesprecisely
thewavevelocityin thesample.Another
improvement
underinvestigation
is to usemultimodeopticalfibersin
order not only to increasethe rangeof scanningvelocities,but also to
controlpreciselythelight distributionon thesurfaceof the sample.This
noncontactmethodof lasergenerationof ultrasonicwavesmay findsome
applicationsin nondestructivetesting.
2:05
I5. Quantitative particle characterizationby ultrasound.Ronald A. Roy
and RobertE. Apfel (Yale University,P.O. Box 2159,New Haven,CT
06520)
An acousticscatteringtechniquewasdevelopedfor determiningthe
compressibility
anddensityof microparticles(diameterlessthan 15/zm),
whichweremodeledasfluid spheres.Toneburstsof 2-/•sdurationand 30MHz center frequencywere scatteredfrom individual microparticlesas
they traversedthe confocalregion of two transducers.The scattered
burstswere detectedat 90' and 180' (backscattering),digitized, and
storedin computermemory.By usingeitherthe Rayleighor Born ap1:35
I3. Ultrasonic wave propagation in multilayered fibrous composites.
Adnan H. Nayfeh (Department of AerospaceEngineering,M.L. 70,
Universityof Cincinnati,Cincinnati,OH 45221) and Dale E. Chimenti
(Materials Laboratory,Wright-PattersonAir Force Base,Dayton, OH
45433)
A unified analytical treatment supportedby extensiveexperimental
dataof the interactionof ultrasonicwaveswith singleand multilayered
S20
J. Acoust.Soc. Am. Suppl. 1, Vol. 82, Fall 1987
proximations,it waspossibleto determinethe compressibility
anddensity
of the particlesgivena priori knowledgeof the particlesize and host
properties.It wassubsequently
possible
to computethe meancompressibility and densityaveragedover a populationof particles,or to display
histograms
of scatteredamplitudestatistics.
An experimentwasrun to
assessthe feasibilityof usingpolystyrenemicrospheresto calibratethe
instrument.A secondstudywas performedon the buffy coat harvested
from whole humanblood.Finally, Chinesehamsterovary cellswerestudied in order to seeif the instrumentcould detect hyperthermia induced
membraneblistering.[Work supportedby NIH and ONP. ]
114th Meeting:AcousticalSocietyof America
$20
2:20
16. Dependeneeon pulse parametersfor free radical productionby
cavitation from short pulsedultrasound.J. !]. Fowlkesand L. A. Crum
(NationalCenterfor PhysicalAcoustics,P.O. Box847,FraternityRow,
University,MS 38677)
Recentdatawill bepresented
thatindicatethepresence
of freeradicals
generated
with peakacousticpressure
amplitudesandpulseshapescharacteristicof somemedicaldiagnosticdevices.The free radicalswcrc detectedvia a chcmiluminescencc
reactionin an aqueoussolutioncontaining luminol using a singlephoton countingtechnique.The acoustic
pressure
thresholdfor lightemission
wasexaminedasa functionof pulse
width,dutycycle,andpulserepetitionfrequency(PRF); possible
explanationsfor thesedependences
basedupona simpleconceptof cavitation
inceptionwill bc presented.[Work supportedby the NationalInstitutes
of Health. ]
2:35
I7. Interaction of Lamb waves with surface-breaking cracks in
centrifugallyeast stainlesssteel (CCSS} plates.Tran D. K. Ngoc and
Kin W. Ng (Department of Physics, Georgetown University,
Washington,DC 20057)
Applicationof conventionalultrasonicnondestructive
evaluation
techniques
to CCSScomponents
in nuclearpowerplantshasbeenlimited
principallydue to the anisotropyof CCSSmaterials.Phenomenasuchas
beamskewingand distortionare directly attributableto this anisotropy
and causeseveredifficultiesin defectdetectionand sizing.The present
investigation
is intendedto useLambwavesasthe probingmechanism
to
detectand characterizea surface-breaking
crack residingon an interior
surfacenotaccessible
by the ultrasonicprobe.Experimentalinvestigation
isdirectedat severaltechniques
for excitinganddetectingLambwavesin
thisapplication.The excitabilityof variousLamb-wavemodesin thefd
(frequencytimesthickness)rangeof interestandtheeffectsof anisotropy
andsurfacecurvatureon modepropagation
characteristics
arealsostudied. Signalsdue to mode conversionand crack diffractionare usedto
developan interpretationprocedurefor crack detectionand sizing.
[Work supported
by EPRI undercontractRP2405-23.]
2:50
18. On a plate/surface wave mode selection criteria for ultrasonic
evaluation in layered structures. A. Pilafski, $. L. Rose, and
K. Balasabramaniam
(Departmentof MechanicalEngineeringand
Mechanics,
DrexelUniversity,Philadelphia,
PA 19104)
The choiceof specific
modeswhileutilizingplateor surfacewaves,in
theultrasonic
evaluation
of layeredstructures,
isextremely
critical,especiallyif thepurpose
isto tuneoursensitivity
to particulartypesof imperfections.
A directapproach
basedontheanalysis
ofeachindividualmode,
for particulargeometrical
configuration
andfrequency
content,is very
time consuming.Therefore,it has been proposed[A. Pilarski, Arch.
Acoust.7, 61-70 (1982) ] to usean indirectapproachby comparingthe
dispersioncurvesfor differentmaterial properties,geometricalconstraints,boundaryconditions,
etc.In thispaper,thistechnique
hasbeen
appliedto a three-layered
aluminum--epoxy-aluminum
adhesively
bond-
$21
J.Acoust.
Soc.Am.Suppl.1,Vol.82,Fall1987
ed structure.This wasachieved
throughthe numericalsolutionof the
characteristic
equationfor sucha layeredstructure.The results'thusobtainedwereverifiedthroughexperimentally
generating
andstudyingthe
behaviorof plate/surface
wavesin specially
prepared
Al-epoxy-Al bonded specimens
with adhesiveweaknesses.
Both immersionand contact
methodsareappliedin our experimental
investigations.
3:05
19. Acoustically generated temperature gradients in plates.
Michael Muzzerall, Anthony A. Atchley, and Thomas J. Hofier
(Physics Department, Naval PostgraduateSchool, Monterey, CA
93943)
The resultsof measurements
of thermoacoustically
generatedtemperaturegradientsin shortthin plateslocatedin a resonanttube'.
are reported.The temperature
gradient,resultingfroma heatflowgenerated
by
the acousticfield, is a functionof the acousticpressureamplitude,the
Prandtlnumberof thegas,theconfigurationof theplates,andthe position
of the platesin the tube,Measurements
weremadefor pressureamplitudesrangingfrom approximately145-162 dB re: 20 ,uPa,in argonand
helium,for singleplatesandstacksof up to fiveplateshavingseparations
from approximately4 to 40 thermalpenetrationdepths,and at various
positions
in the tube.The resultsare comparedto predictions
basedon a
theoryby Wheatleyandothers[ J. WheatIcyeta/., J. Acoust.Soc.Am. 74,
153-170 (1983)]. For pressureamplitudesbelow150dB, the measurementsagreewell with theory.At higherpressureamplitudes,the agreementdiminishes,
indicatingthe presence
of effectsnot addressed
by theory. [Work supportedby NPS Foundation.]
3:20
110. Possibilityof improvedlaser-Dopplerdetectionof soundby tracking
moving phase fronts. Allan D. Pierce (School of Mechanical
Engineering,GeorgiaInstituteof Technology,Atlanta, GA 30332)
Laser-Doppler anemometryapplied to acousticspresentsspecial
problemsbecauseof the small velocitiesof fluid flow associatedwith
soundand becauseof the relatively rapid oscillations.The analysisof
Hanish,attributedto GeneralElectricCompany(1967) anddemonstrated by K. J. Taylor in 1976and 1981,showssuchproblemscanbe overcomein majorpart for singlefrequencysoundusingthespectraldensityof
the photomultipliertube output. Comparablesuccessis unlikely for
broadbandsound;an "uncertaintyprinciple" requiresaveragingover
time intervalscomparableto the reciprocalof the Doppler shift in frequency;no blackboxelectronicscan beatthis principle.Difficultiesappearinsurmountable
if characteristic
acousticfrequencies
aremuchhigher than the Doppler shift. A possibleway of overcomingthis is to take
advantageof the constancyof the soundspeedand of the omnidirectionality of incomingsound.Opticalsystems
canbedesigned
whichmovethe
effectiveoptical scatteringvolume along nearly rectilinearpathsat the
soundspeedsuchthat the laser tracksa movingphasefront. The fluid
velocitysensedby the laserthusappearsto beconstantratherthan oscillating, so one has the opportunityto examinemeaningfulaveragesover
sufficientlylongtime periods.[Work supportedby ONR.]
114thMeeting:
Acoustical
Society
ofAmerica
S21
TUESDAY
AFTERNOON,
17 NOVEMBER
1987
UM AUDITORIUM,
1:00 TO 5:17 P.M.
SessionJ. SpeechCommunicationII and Bioresponseto Vibration I: Special Focuson SpeechPerception
Using Tactile Aids
RebeccaEilers, Chairman
Mailman Centerfor Child Development,Universityof Miami, P.O. Box 016820,Miami, Florida 33101
Chairman's Introduction--l:00
Invited Papers
1:05
Jl. Evaluations of singJe-ehanneland multichannel tactile aid• for the hearing impaired. Janet
M. Weisenberger(Central Institute for the Deaf, 818 S. Euclid, Saint Louis,MO 63110)
A numberof single-channel
and multichanneltactile devicesfor hearing-impairedpersonshave been
evaluated
in ourlaboratory
overthelastseveral
years.Bothcommercially
available
andexperimental
devices
havebeentested,includingtheTactaidI, II, andV, Minifonator,Minivib,Queen'sUniversitytactilecocoder
(both laboratoryand wearableversions),and TacticonTC-1600. Normal-hearingand hearing-impaired
adults,andhearing-impaired
children,haveparticipated
in a varietyof trainingtasks,employing
bothrecorded and live-voicestimuli. Thesetasksincludesimpledetectionof sound,environmentalsoundidentification,
syllablerhythmandstresscategorization,
phonemeidentification,
word identification,
phraseand sentence
identification,
connected
discourse
tracking,anda question-and-answer
"conversation"
task.In thepresent
paper,theresultsfromtheseevaluations
areconsidered
asa whole,to permitgeneralizations
aboutthekindsof
informationthat canbeprovidedby single-channel,
dual-channel,and multichanneldevices,with and without
theadditionof lipreading.In addition,resultsarediscussed
in termsof thedevelopment
of"optimal"training
procedures
for the useof tactileaids. [Work supportedby NSF and NIH.]
1:35
J2. Speechperception
throughthesenseof touchby profoundlydeafadultsandchildren.MichaelP. Lynch,
RebeccaE. Eilers,and D. K. Oiler (Departmentsof Psychology
and Pediatrics,Universityof Miami,
MailmanCenterfor ChildDevelopment,
P.O. Box016820,Miami, FL 33101)
Eightcongenitally,
profoundly
deafchildrenandtwodeafadultsreceived
unimodalvocabulary
recognition training with either a multichannelelectrotactileaid or a two-channelvibrotactileaid. The children
learnedto recognizevocabularies
of 15-20wordswith 70%-80% accuracy.The adultslearneda 50-wordlist.
Followingthis training,subjects'
identification
of familiarand novelwordswasassessed
usingthe tactile
devicesand aidedaudition.Vocabularyrecognition
wastestedin eachof threeconditions:( 1) with aided
audition,(2) withdualor multichannel
aid,and( 3) withbothtactualandauditoryaids.Resultsindicatethat
auditoryandtactualcuesweresuccessfully
integratedby bothchildrenandadultsto yieldsignificantly
better
performance
in combinedthan in singlemodalityconditions.
An additionalstudyof the narrativetracking
performance
of oneof thedeafadultsrevealed
a similarsynergistic
interplayoftaction,audition,andlipreading. [Work supportedby Rita andJeromeCohen,RenataMahan, and Austinand Marta Weeks.]
2:05
J3. Lipreading with single-channelvibrotactile presentationof voice fundamental frequency. Lynne
E. Bernstein,SilvioP. Eberhardt(SpeechProcessing
Laboratory,Departmentof Electricaland Computer
Engineering,
JohnsHopkinsUniversity,Baltimore,MD 21218), and Marilyn E. Demorest(Departmentof
Psychology,
Universityof MarylandBaltimoreCounty,Catonsville,MD 21228)
A studyevaluatedseveraltransformations
ofvoicefundamentalfrequency(F0) for usebya single-channel
vibrotactiledeviceto supplementlipreading.The experimentalprocedureinvolvedlipreadingstimuli from a
corpusof over 1500sentences
storedon a videolaserdisk[L. E. Bernsteinand S. P. Eberhardt,1986,Johns
HopkinsLipreadingCorpus].There werefive experimentalconditions.Three transformations
of voiceF0
were tested:two transformed F0 to a pulserate code, the third employed two sine wavesthat were amplitude
modulatedasa functionofF0. Condition4 providedbothF0 and a secondstimulatorindicatinghigh-frequency speechenergy.Condition5 wasvisualalone.Subjects
were 15 normal-hearingadultsin a multiplesinglesubjectdesignwith alternatingbaselineandtestsessions.
Analysesof covariancefor wordscorrect,wordsper
stimulussentence,
and syllablesper sentenceshowedthat all subjectsimprovedin lipreading.Subjectswho
receiveda singlevibratorfor voiceF0 lipreadmoresuccessfully
thansubjects
whodid notreceivethevibrotactile supplement
or who receivedthe dual tactilestimulation.
S22
J. Acoust.
Soc.Am.Suppl.1, Vol.82, Fall1987
114thMeeting:
Acoustical
Societyof America
S22
2:35
J4.Tactilespeech
reception
usingaugmented
Tadurea.
C. M. Reed,W. M. Rabinowitz,
andN. I. Durlach
(Research
Laboratory
ofElectronics,
Massachusetts
Institute
ofTechnology,
Cambridge,
MA 02139)
Results
obtained
withTadurea
haveseta newstandard
forthetactile
communication
ofspeech
[Reedet
M., $. Acoust.Soc.Am. 77, 247-257(1985)]. Theseresults,
however,
areinferiorto thoseobtained
in the
normal
auditory
domain:
theyareroughly
comparable
tothose
obtained
bynormal-hearing
subjects
listening
tospeech
in signal-to-noise
ratiosof0-6 dB.Thegoalof thecurrent
research
isto augment
Tadurea
with
supplementary
tactiledisplays
to improve
theperception
of speech
segments.
Among
thesupplementary
displays
investigated
werea vibrotactile
display
of tongue
contact
withthehardpalateanda vibrotactile
display
oftheshort-term
speech
spectrum.
Thetongue-palate-contact
display
waseffective
forimproving
the
discriminability
ofpairsofconsonants
difficult
todistinguish
through
Tadurea;
however,
neither
thisdisplay
northemultichannel
spectral
display
proved
tobeeffective
foraugmenting
voweldiscriminability.
A third
approach
toaugmenting
Tadurea
currently
underinvestigation
involves
thetactilereception
ofcuedspeech.
[Work supportedby NSF. ]
3:05
JS. Temporaland spatiotemporal
tactile transformsof voice fundamentalas an aid to lipreading.
Arthur Boothroyal,
TheresaHnath-Chisolm,
andLaurieHanin(GraduateSchool,
CityUniversity
of New
York, 33 W. 42 Street, New York, NY 10036)
Lipreading
scores
ofnaivesubjects
risedramatically
whenthevisiblespeech
movements
aresupplemented
byauditorypresentation
ofvoicefundamental
frequency(F0). If it canbeshownthatthetactualtransmission
of F0 providessimilarresults,thenthereis the possibility
of developing
an effectivelipreadingaid for deaf
subjects.
Wehavetestedtwovibrotactile
transforms
ofF0. Oneistemporal.It involves
single-channel
stimula-
tionwithaconstant-amplitude
square
wave,offrequency
FO/2, atafixedlocus.
Thesecond
isspatiotemporal.
It usesthesamestimulus,
but locusvaries,displacement
beingproportional
to log(F0). Thistransformrequiresa multichannel
stimulator.In psychophysical
experiments,
the temporaldisplayhasbeenfoundto
provideroughly1/3-octresolution
at thefingertip,
butoverI octontheforearm.Withappropriate
scaling,
an
eight-channel
spatiotemporal
displayprovidesapproximately1/3-oct resolutionon the forearm.With 16
channels,1/6 of an octaveresolution
is possible.
Experiments
with speechstimulihaveshownthat both
displays
enhancethevisualperception
of phoneticcontrasts
that involvedurationalcues,but that themultichanneldisplayisa moreeffective
lipreading
supplement
for contrasts
involvingintonation
contrasts.
When
sentence
materialwasusedwithnaivesubjects,
thetwodisplays
provided
onlya smallsupplement
to lipread-
ing.In oneexperienced
lipreader,
however,
workingwiththemultichannel
displayovera 13-week
period,
supplemented
performance
wassignificantly
betterthan unsupplemented
performance.
The additionof the
spatiotemporal
transformofF0 to thevisualsignalreducedthenumberof wordrecognition
errorsby 50%. A
wearable
versionof themultichannel
displayhasbeendeveloped
andiscurrentlyin usein fieldstudies.[Work
supportedby NIH PPG# 17764.]
3:35-3:50
DISCUSSANT: D. KimbroughOller, University
of Miarni
3:50-4:05
Break
ContributedPapers
4:05
J6.
A
wearable
multichannel
vibrotactile
aid
for
the deal
A.
Maynard Engebretson,FengminGong, and Michael P. O'Connell
(Central Institute for the Deaf, 818 S. Euclid Avenue, St. Louis, MO
63110)
to the 16-channel
vocoderalgorithm,themicroprocessor-based
system
canbeprogrammed
to implement
otherprocessing
algorithms
usingthe
existing
hardware.
Thesystem
anditsperformance
characteristics
willbe
described.
[Work supported
in partby NIH.]
It hasbeendetermined
that hearing-impaired
and normal-hearing
subjects
canlearnto identifywordsusingonlya tactilevocoder[ Brooks
and Frost, J. Acoust.Soc.Am. 74, 34-39 (1983) ]. Further studieshave
shown
thatcertainmultichannel
tactilevocoders
provide
significant
help
in understanding
connected
discourse
as an aid in lipreading[Weisenbergerand Miller, J. Acoust.Soc.Am. 82, 906-916 (1987) ]. A reviewof
thisresearch
isgivenin a companion
paper(Weisenberger,
AbstractJ1).
Motivated by theseresults,a wearable, 16-channelvibrotactile aid has
beendeveloped
thatcanbeusedbyhearing-impaired
subjects
duringnormaldailyactivities.
Thesystem
consists
of a body-worn
processor
thatis
3.5X 5.5X 1.5in. in sizeanda vibratorarraywornon thearm. In addition
S23
J.Acoust.
Sec.Am.Suppl.1,Vol.82,Fall1987
4:17
J7. Evaluation of a multichannelelectrotactiledevicefor the hearing
impaired--A casestudy.Linda Kozma-Spytek
and JanetM. Weisenberger (Central Institute for the Deaf, 818 S. Euclid, St. Loais, MO
63110)
A multichannelelectrotactile
devicefor the hearingimpairedwas
evaluatedasanaidfor speech
receptionandproductionwitha 12-year-old
profoundlyhearing-impaired
childenrolledin an oralschoolfor thedeaf.
Overan 8-monthperiodthesubject
received
trainingin speech
reception
114thMeeting:
Acoustical
Society
ofAmerica
S23
skillsin a hierarchyof tasksrangingfrom discrimination
of minimal
pairedwordsto connected
discourse
tracking.Aspectsof the subject's
speech
production
skillswereevaluated
byobtaining
ratings
fromagroup
of teachers
of thehearingimpaired,whovieweda videotape
of thechild
duringsyllableproductionandconnected
discourse
trackingwith and
withoutthe device.Resultsof speechreceptiontestingindicatedthat the
deviceallowedgooddiscrimination
of minimalpairedwordsbasedon
mannercontrasts,
but poordiscrimination
basedonplacecontrasts.
Dur-
ingtracking,lipreading-pulse-tactile
aidconditions
weresuperior
to lipreadingalone.Resultsof the speechproductionevaluationshowedthat
syllableidentification
wasbetterandratingsonseveralaspects
of speech
production
werehigherundertactileaidconditions.
[Worksupported
by
thetactileconditionexceeded
performance
in theauditoryconditionfor
thosestimulusitemscontaininga frequencycue. [Work supportedby
#NS-17764.]
4:53
J10. Reliability of individual differences in lipreading. Marilyn
E. Demorest (Department of Psychology,University of Maryland
Baltimore County, Catonsville,MD 21228), Lynne E. Bernstein,and
Silvio P. Eberhardt(SpeechProcessing
Laboratory,Departmentof
Electrical and Computer Engineering,Johns Hopkins University,
Baltimore, MD 21218)
4:29
JS.Tactile receptionof fingerspelling
andsignlanguage.C. M. Reed,L.
A. Dclhorne, and N. I. Durlach (Research Laboratory of Electronics,
Massachusetts
Instituteof Technology,Cambridge,MA 02139)
Previous
workon tactilespeech
reception
by deaf-blind
individuals
hasfocusedon the Tadoma method [Reed et al., J. Acoust. Soc.Am. 77,
247-257 (1985) ]. Two additional methodsof tactile communication,
bothofwhicharcadaptations
of methods
designed
forthevisualsense
but
areusedextensively
withinthe deaf-blindcommunity,arctactilefingerspellingandtactilesigning.The goalof thecurrentresearch
wasto documentthe communication
abilitiesof highlyexperienced
deaf-blindusers
of tactilefingerspelling
andtactilesigning.Experiments
wereconducted
todeterminereception
accuracy
forsentence-level
materialsasa function
of rateof presentation
for eachof thetwo methods.The resultsof these
experiments
will be compared
to thoseobtainedfor visualreception
of
fingerspelling
and signingas wcil as to resultsobtainedthroughthe Tadoma methodof tactile speechcommunication.[Work supportedby
Evaluationof the benefitsof sensoryaidsrequiresstimulusmaterials
whosepsychometric
characteristics
are known.Generalizability
theory
wasappliedto datafromtwo experiments
to estimatemeasurement
error
arisingfrom differentmaterials,differenttalkers,and practice.Stimulus
materialsconsisted
of CID sentences
andCV nonsense
syllablesproduced
by a maleand a femaletalker andstoredon videolaserdisk.In experiment
I, 104normal-hearing
subjects
lipreadthe CID sentences
in a singletest
session. Results indicate that there are substantial individual
differences
in lipreadingperformance
amongsubjects,
but that therearealsosystematic differencesamongsentences
and amongtalkersthat must be taken
into accountin interpretingtestperformance.In experimentII, 15 normal-heatingsubjectswho participatedin an intensivetrainingprotocol
involvingvibrotactilesupplements
to lipreadingweregivenpre-andposttestson theCID sentences
andon theCV syllables.
Individualdifferences
in performance
on sentences
werehighlystableoverthe trainingperiod,
suggesting
relativelyuniformimprovements
due to training.Reliability
overtime waslowerfor the CV syllablesand correlationsbetweenthe CV
andsentence
materialswereweakbothat thepretestandposttest.[Work
supportedby NIH. ]
NIH.]
5:05
Jll.
4:41
The use of tactile aids with deaf-blind children. Barbara Franklin
(Departmentof SpecialEducation,SanFranciscoStateUniversity,San
Francisco,CA 94132)
J9. Stresscontrastperceptionby the hearingimpaired:Auditory, tactile,
auditory-tactile.JanctRcath SchoepfiinandNancyS. MeGart (Speech
and Hearing Sciences,Graduate School and University Center, City
Universityof New York, New York, NY 10036)
The perceptionof stresscontrastsin deafsubjects
wasassessed
under
three conditions--auditoryonly, tactile only, and combinedauditorytactile. Test stimuli were three disyllablesgeneratedin a two-stageproccss:multiplerepetitions
of eachdisyllablcwereproduced
by a normally
hearingspeakerusingnormalor exaggerated
stresson eitherthefirstor
secondsyllable;the averagedacousticvaluesfor peakamplitude,vowel
duration,and peakfundamentalfrequencyfor eachdisyllablewerethen
resynthcsized
and manipulatedto createa stimulussetcontainingnone,
one, two, and threeof the acousticcuesdenotingstress.Subjectswere
askedto indicatewhetherstressoccurredonthe firstor secondsyllablefor
This paperwill presentthe resultsof the firstyearof a 3-yearstudy
designedto comparethe effectsof a 2-channel(Tactaid I!) and a 16channel(Tacticon)aidonexpressive
andreceptive
communication
skills
of deaf-blind children. Tbe Tactaid vibrators are worn on the wrist and the
Tacticon is worn as a belt of electrical stimulators on the abdomen. Six
children,rangingin agefrom22monthsto 18years,fromtheSanFranciscoBayareaareparticipating
in thestudy.A totalof threecommunicative
behaviors
will beselected
for eachchild (e.g.,numberof purposefulvocalizations).A single-subject
designwill beusedtocompare
theircommunicationbehaviors
in threeexperimental
conditions--nodevice(control),
2-channeldevice,and 16-channeldevice.Only one behaviorwill be ob-
each stimulus item. Performance was above the level of chance in all three
servedat a time, resultingin threeseparatesub-studies
per child.This
paperwill present
theresults
of Sub-Study
# 1.Despitethetactiledefensiveness
oftenexhibitedby deaf-blindchildren,thepattipantshavebeen
toleratingbothdevices.
[Thisresearch
isbeingsupported
byU.S.Dept.of
conditions.In the exaggeratedstressproductionmode,performancein
Educ. Grant #G008630416.]
$24
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall 1987
114thMeeting:Acoustical
Societyof America
024
TUESDAY AFTERNOON, 17NOVEMBER 1987UNIVERSITY LECTURE HALL, 1:15TO 3:45P.M.
Session
K. Psychological
andPhysiological
Acoustics
II: Loudness
andAuditoryFatigue
S•ren Buus, Chairman
Department
ofElectrical
andComputer
Engineering,
Northeastern
University,
360Huntington
Avenue,
Boston,
Massachusetts 02115
ContributedPapers
1:15
K1. Absolutemagnitudeestimationof loudness
by adultsand children.
edin accordance
witha loudness-calculation
programbasedonISO 532B
[E. Zwicker, H. Fast, and C. Dallmayr, Acustica55, 63-67 (1984)].
Data are givenfor singletonescenteredwithin the spectrumof broad-
GeorgeA.GescheiderandAmyA.
Collins(DepartmentofPsychology, band-flat,low-pass,and high-passnoises.The measuredand calculated
HamiltonCollege,Clinton,NY 13323)
tonesassigned
thesamenumberin magnitude
estimation
werejudgedto
besubjectively
equalincross-modality
matching.
A correction
procedure
wasemployed
toeliminate
theeffects
ofidiosyncratic
number
usage
from
themagnitude
estimations
of loudness.
Thiscorrection
procedure,
consistingof dividingthe loudness
exponent
by the line lengthexponent,
loudness
functionsexhibita similarpatternof loudness
growth.Both
measuredand calculatedloudness
of the tone-noise
complexes
are nonmonotonicfunctionsof the overallSPL of the complex.Thus two tonenoisecombinations
at nearlythesameoverallSPLcanproducemarkedly
differentloudness
values.Theseresultshold overa 30-dBrangefrom
about73-103 dB. The resultsalsoshowthat the magnitudeof loudness
depends
on thespectralshapeof thenoiseandthefrequency
of theadded
tone.Thecloseagreement
betweenthemeasured
andcalculatedloudnessgrowthpatternsmeansthat basicpsychoacoustical
principles
governing
loudness
andmaskingcanaccountfor theobserved
effects.[Supportedby
the RehabilitationResearchand DevelopmentServiceof the VA andby
produced
powerfunctionexponents
for loudness
thatwerevirtuallyiden-
the DeutscheForschungsmeinschaft.
]
Twenty-three
subjects
performedabsolute
magnitude
estimation
of
thelengthsof a seriesof linesandtheloudness
of a seriesoftonesaswellas
cross-modality
matching
between
loudness
andperceived
linelength.The
resultssupportthehypothesis
that subjects
judgestimulion an absolute
scale.Specifically,for 9 out of 12adultsand 9 out of 11children,linesand
ticalfor magnitude
estimation
andcross-modality
matching.
Implications of the results for clinical measurement of loudnessare discussed.
2:00
1:30
K•. Deviationsfrom a power-functionnear missand their relation to
loudness
functions.
WilliamS. Hellman(Department
ofPhysics,
Boston
University,
Boston,
MA 02215)andRhonaP. Hellman(Department
of
Psychology,
Northeastern
University,Boston,MA 02115)
In a previouspaper[W. S. Hellmanand R. P. Hellman,J. Acoust.
Soc.Am. Suppl.1 81, S53-S54(1987)], theneural-count
functionN(1)
wasderivedfromthe intensity-jnd
functionJ(1) throughthe relation
K4. Psychometric functions for level discrimination. S6ren Buus
(Communicationand Digital Signal ProcessingLaboratory,409 DA,
NortheasternUniversity, Boston,MA 02115), Christine R. Mason, and
Mary Florentine (Communication Research Laboratory, 133 FR,
NortheasternUniversity,Boston,MA 02115)
To determinethe form of psychometric
functionsfor 2I, 2AFC level
discrimination,ten incrementlevelswere presentedin random order
withinblocksof 100trials.Stimuliwerechosen
toencompass
a widerange
of conditions
anddifference
limens:eightI O-mstoneshadfrequencies
of
N(1)4/2= (h/2)œdl/[IJ(1) ] + a.Loudnessfunctionswerethengenera0.25, 1,8, or 14kHz and levelsof 30, 60, or 90 dB SPL; two 500-msstimuli
tedby theprescription
L = kiN(I) - N]. Usinga power-function
near
also were tested: a l-kHz
missforJ(I), goodagreement
betweenthemeasured
andcalculatedloud-
SPL.For eachcondition,at least20 blockswerepresented
in mixedorder.
Resultsfor threenormallistenersshowthat the sensitivityd' is nearly
nessvaluesfor puretoneswasobtained.
Whilea powerfunctionyieldsa
simple
evaluation
of theintegral
forN(I) •/2,theresults
of manyrecent
jnd studies
do not easilyconformto a power-function
fit. In orderto
determine
howthedepartures
froma power-function
nearmissaffectthe
formoftheloudness
function
withinthemodel,
theintegration
wasperformed
overthesegmented
intensity
jndfunctions
observed
forgated
and
continuous
tones.
Thecalculated
loudness
functions
andtheirrespective
inputintensity
jnd functions
areshownforfrequencies
of 250and1000
Hz. In spiteofthesegmented,
andin someinstances,
nonmonotonic
inten-
sityjndfunctions,
theresults
revealthatthesmoothing
actionoftheintegration
overJ(I) produces
loudness
functions
consistent
withexperimen-
tone at 90 dB SPL and a white noise at 63 dB
proportional
to AL{ = 20log[(p + Ap)/p], wherep is pressure}
over
the entirerangeof difference
limens.Whend' is plottedagainstWeber
fractions
for pressure
Ap/p or intensityAI/I exponents
of thebest-fitting
powerfunctionsdecreasewith increasingdifferencelimensand are less
thanonefor largedifference
limens.Theseresultsindicatethat the transformationfrom stimulusintensityto decisionvariablemay be approximatelylogarithmicand that z•L--plotted on a logarithmicscale•is an
appropriaterepresentation
of leveldiscriminationperformance.[Work
supportedby NIH. ]
tal results.[Partially supportedby the RehabilitationResearchand
DevelopmentServiceof the VA. ]
2:15
1:45
KS. Investigationof a modelof loudness.P.S. Chiena> (Center for
Researchin Speechand HearingSciences,
City Universityof New York,
K3. Overall loudness
of tone-noise
complexes:
Measuredandcalculated.
New York, NY 10036} and J. L. Hall (AT&T Bell Laboratories, Room
RhonaHellman (Auditory PerceptionLaboratory,Northeastern
2D526, 600 Mountain Avenue,Murray Hill, NJ 07974)
University, Boston, MA 02115) and Ebcrhard Zwicker (Institute of
Electroacoustics,
TechnicalUniversityof Munich, Munich, Federal
Republicof Germany)
Loudness
measured
for single-tone-noise
complexes
[ R. P. Hellman,
J.Acoust.Soc.Am. 72,62-73 (1982)] iscompared
to loudness
calculat-
S25
J.Acoust.
Soc.Am.Suppl.1,Vol.02,Fall1907
A modelof loudnesssummationby Schroederet al. [J. Acoust.Soc.
Am. 66, 1647-1652(1979) ], whichwasusedby themto provideanobjective qualitymeasureof digitalspeechcoding,is beinginvestigated.( 1)
Iso-loudness
contoursgeneratedby the modelare comparedto iso-loudnesscontoursgeneratedby human subjects.(2) The spreadingfunction
114thMeeting:
Acoustical
Society
ofAmerica
S25
used in the model to calculate excitation levels is converted from the
Serpente,
75006Paris,France),S.Mfinikheim
(InstitutffirPsychologie,
critical-band
domainto thefrequency
domainforvariouscenterfrequencies.Theresulting
curves
arecompared
totuningcurves
measured
in the
cat. (3) The effectof partialmasking
ontherelativeloudness
of pairsof
Wfirzburg,Austria),andB. Schaff(Northeastern
University,
Boston,
puretonesisexamined.
(4) Themodelisusedtopredicttheloudness
of
broad bandsof noisefrom the loudnessof narrow bandsof noisecentered
atseveral
frequencies.
Studies
( 1)-(4) haverevealed
strengths
andshortcomings
ofthemodel.a•Workdoneasaconsultant
toAT&T BellLaboratories.
MA02115)
Measurements
of inducedloudness
adaptationandtemporarythresholdshift(TTS) weremadeon48 youngsubjects.
Loudness
adapatation
of
a continuous
60-dBtesttonewasinducedin therightearby an intermittent 1000-Hzinducertoneat 90 dB, presented
every30 s for 20 s. The
loudnessofa 1000-Hz or 1160-Hz testtone at 60 dB was measuredafter
eachoccurrence
of the inducerby the methodof successive
magnitude
estimations.
Inducedadaptation
causedthe loudness
of the continuous
toneto decrease
on theaverage
by 38% (the equivalent
of 14dB) after
2:30
K6. Loudness
adaptation
in musicians
andnonmusicians.
C. Baruchand
M.-C. Bottc(LaboratoiredePsychologie
Exp6rimentale,
CNRS, 28 rue
Scrpente,75006Paris,France)
Measurements
of simpleandinducedloudness
adaptationwcrcmade
on 10-12 musiciansand 10-12 nonmusicians
by the methodof successive
magnitude
estimations.
Simple
adaptation
(SA) wasmeasured
fora 500-,
1000-,or 4000-Hz tone presented
monaurallyfor 3 rain at 10 dB SL.
Inducedadaptationwasmeasured
for a continuous
1000-Hz,60-dBSPL
120s.In a separate
session,
thesubject's
rightearwasexposed
for45rain
to a 1000-Hztoneat 90 dB SPL. One minuteafter exposure,thresholds
weremeasured
by B6k6sy
trackingfor 4 min.The maximumTTS, aver-
agedacross
subjects,
was20.4dBat a meanfrequency
of 1635Hz. The
correlationbetweenmaximumTTS and the amountof inducedadapta-
tionwas0.83.Thusipsilaterally
induced
adaptation
(IIA), whichisakin
totemporary
loudness
shift,maystemfromcochlear
mechanisms
justas
TTS does.Also, IIA couldbecomethe basisfor an audiological
testto
identifythoseindividuals
mostsusceptible
to auditoryfatigue.[Work
supported
byMinist•redel'Environnement
andNIH. ]
right-cartone;loudness
wasjudgedbefore,
during,andaftereachoccurrenceof an intermittentinducertone set to five frequencies
from 500-
3260Hz andpresented
every30 s for 10s to thesamecar (ipsilatcrally
inducedadaptation,
IIA) or to theleftear (contralaterally
inducedadaptation,CIA). We alsomeasured
CIA with a rapidintermittcncyof every1
3:15
s for 0.5 s. The level of the inducer was 60 dB for CIA and 75 dB for IIA.
Musiciansshowedlessadaptationthannonmusicians
whateverthetype
of adaptation:For the musicians,
the maximumloudness
decrease
was
44% under SA, 30% under CIA, 30% under IIA; for the nonmusicians,
this maximum was70% underSA, 70% underCIA, 41% under IIA, but
differences
werestatisticallysignificant
onlyfor SA andfor CIA with the
rapidintermittency.
Moreover,musicians
showedsignificant
adaptation
overa lessextendedrangeof frequencies
thannonmusicians.
2:45
K9. Reductionof auditorydamagedueto intermitrenee.
W. Dixon Ward
(2630UniversityAvenueS.E., Minneapolis,
MN 55414)
Twogroups
ofchinchillas
weregiven
dailyexposures,
5days/week
for
9 weeks,to 700-2800-Hznoiseat 110 dB SPL. Each day, one group
received
a single
48-minexposure,
theothergroupa series
of40 1.2-min
bursts
spaced
at 12-minintervals.
Whereas
thecontinuous
single
exposures
produced
a median
permanent
threshold
shift(PTS)of 16dBat 1,
2, and4 kHz anddestruction
of 33% oftheouterhaircells(OHCs), the
intermittent
exposures
resulted
in a PTSof only6 dBandlessthan5%
destroyed
OHCs.Inasmuch
asthelattergroupsuffered
aboutthesame
cochlear
damage
as(andlessPTSthan)a groupgiven45daily48-min
K7. A pure-tone-induced
temporarythresholdshift on normalhearing
and noise-inducedpermanentthresholdshift. I. M. Young and L.
exposures
at 102dB SPL,onecaninferthatan 8-dB"correction
for
D. Lowry(Department
ofOtolaryngology,
Jcffcrson
MedicalCollcgc
of
dancewith present
OSHA regulations
governing
industrial
noiseexpo-
ThomasJefferson
University,Philadelphia,PA 19107)
sure.[Researchsupported
by NIH Grant 12125.]
Temporarythresholdshiftafteran exposure
to a puretonewasmeasuredbyautomatic
audiometry
onthreesubjects
withnormalhearingand
threesubjects
with noise-induced
permanent
threshold
shift.Subjects
wereexposed
to a stimulating
puretonewith a frequency1500Hz
throughanearphone
at anintensity
of 110dB SPLfor a durationof 10
min.Temporary
threshold
shiftwasmeasured
beginning
at 5 s afterthe
cessation
of thestimulation.In normalhearingsubjects,
thegreatest
shift
wasobserved
at thefrequency
areaof 2000Hz asdemonstrated
previously. In subjects
withnoise-induced
permanent
threshold
shift,temporary
thresholdshiftwasdemonstrated
notonlyat thefrequencyregionof 2000
Hz, but alsoat higherfrequencies
with permanentthresholdshift.Post-
exposure
effects
at higherfrequencies
showed
thegreaterthreshold
shift
forthesteady
toneresulting
in increased
separation
between
normalamplitudepulsedtonetracings
andmarkedlyreduced
amplitude
steadytone
tracings.
Similarpost-exposure
findings
wereobserved
ona subject
with
congenital
nonprogressive
bilateralsymmetrical
sensorineural
lossof
highfrequencies
similarto noise-induced
permanent
threshold
shift.
Spreadof temporarythresholdshift at the higherfrequencies
wasdiscussed
andcomparedwith the greaterspreadof maskingeffectat the
higherfrequencies.
'3:00
KS. Auditoryfatigueandinducedloudness
adaptation.S. Charron,M.C. Botte (Laboratoirede PsychologieExp6rimentale,CNRS, 28 rue
S26
J.Acoust.
Soc.Am.Suppl.1,Vol.82,Fall1987
intermitrenee"
of a 110-dBexposure
is approximately
correct,in accor-
3:30
KI0. Threshold recovery functions following impulse noise trauma.
Roger P. Hamernik, William A. Ahroon (Auditory Research
Laboratories,StateUniversityof New York, Plattsburgh,NY 12901),
and James H. Patterson (Sensory Research Division, U.S. Army
AeromedicalResearchLaboratory,Fort Rucker, AL 36362-5292)
An analysisof the pure-tonethresholdrecoveryfunctionsobtained
from 118 chinchillasexposedto high-levelimpulsenoiseshowedthat
there are at leastthree distinctlydifferenttypesof thresholdrecovery
functions.
TypeI: theclassical
recovery
functionthatdeclines
monotonicallywith increasing
postexposure
time;typeII: a delayedrecovery,i.e.,
for a periodas longas 6 h followingremovalfrom noise,the pure-tone
thresholdremainselevatedand stablebeforea monotonicallydeclining
recoveryprocess
setsin; andtypeIII: the growthfunction,i.e., overa
periodof at least6 h followingremovalfromthenoise,pure-tone
thresholdscontinueto getworsebeforea stablemonotonically
decliningrecoveryprocess
begins.Frequencies
characterized
by a typeIII recoveryprocessshowmorePTS and sensorycell lossthan do thosecharacterizedby
the type I recoveryprocess.
The existence
of threedistinctlydifferent
audiometric
recovery
functions
impliestheexistence
of differentmechanisms of cochlear trauma.
114thMeeting:
Acoustical
Society
ofAmerica
S26
TUESDAY AFTERNOON,
17 NOVEMBER
1987
TUTTLE SOUTH ROOM, 1:30 TO 4:15 P.M.
SessionL. Noise II: Analysis and Reductionof Noise
Krish Krishnappa,Chairman
Engineering
Laboratory
M-7, NationalResearch
Councilof Canada,MontrealRoad,Ottawa,OntarioK1,4OR6,Canada
Chairman's Introduetion•l:30
ContributedPapers
1:35
LI. Tone genemtina by impingementon piate• by suDersoniejets at
v•rious over-pressures.Alan Powell (D•par•ment of Mechanical
Engineering,Universityof Houston,Houston,TX 77004)
Sonicjetsat "moderate"over-pressure
impinging
onnormal,fiat,rigid platesgenerate
intenseprincipal
tonesbytwodistinctmechanisms
[see
J. Acoust.SOc.Am. Suppl.I gl, S96(1987)]. For smallplatesd/Dg2,
(d = platedlam,D = nozzlediam) a local"feedback"
occursin thesobsonicregionbetweenthestand-offshockwaveand the plate,akin to that
in the Hartmannair-jetgeneratorwhenoperatedat the samepressure,
with •./D ___
4(,• ----acousticwavelength).For largeplates(d/D•2) an
edgetone-like
acoustic
feedback
to thenozzleoccursthroughtheambient
atmosphere
externalto thejet and,•/D_2. The unstableshockwaveis
excitedfrom the downstream
and upstreamsides,respectively.Secondarytonesalsoarise,occurringinstead
of theprincipaltone.Somehave)[/
Z)m1, and are directlyrelatedto the largeplatetones,evenfor small
plates,whileothersarealsoclosely
relatedtotheedgetone-like
tones,but
are of slightlylongerwavelength.
This classification
enablesa rational
analysisand interpretation
to be madeof data in the sparseliterature,
includingthosefor supersonic
jetsandjetsat "high"over-pressures,
and
"veryhigh"over-pressures,
in whichcasethetonemechanisms
appearto
merge,with,•/D• 4.
Panelabsorbers
are very usefulin reducingthe noisepropagatedin
pipesandductsin applications
wherereactivemufflers
cannotbeused.A
panelabsorber
ismadeof a rectangular
panelbackedby an air gap.It is
believed that this is the first time detailed studies have been made on the
applications
ofpanelabsorbers
inpipesandducts.Oovcrning
differential
equations
arederivedconsidering
thelumpedanddistributed
springmass
systems.
TheordinaryandpartialdLffcrential
equations
aresolved
andthe
expressions
for thenaturalfrequencies
andtheadmittance
of thepanel
absorber
areobtained.Equations
for theinsertionlossandthetransmissionlossof thepanelabsorber
arcderived.Tendifferenttypesof alumi-
numpanelabsorbers
havebeendesigned,
fabricated,
andtestedin the
Soundand VibrationLaboratoryat Auburn University.Panelabsorber
parameters
suchaspanelthickness,
paneledgesupport(boundary)
conditions,panelabsorber
mounting,
andpaneldimensions
wereconsidered
duringthe experiments.
The locationof the panelabsorber
alongthe
lengthof thepipewasalsoexamined.
Theexperimental
resultsarevery
encouraging.
Insertion
lossofthefirstpanelabsorber
was2.8dB,whereas
theinsertion
lossofthelatestpanelabsorber
withalltheimprovements
is
18 dB.
2'.2O
L4. Resonance
conditionsin branchingstructures.David T. Raphael
andM. A. F. Epstein(Departmentof Anesthesiology,
Universityof
ConnecticutHealth Center,Farmington,CT 06032)
1:50
In complexbranching
structures,
reeursive
algorithms
areoftenemL2. How/acousticinteractionin duetinflow.MargaretC. Quinn (The
Institute of Soundand Vibration Research,SouthamptonUniversity,
Southampton
SO95NH, UnitedKingdom)
Soundgeneration
in theconvection
of turbulence
intoa flowintake
ductisdiscussed
by examination
of an idealizedproblem.Idealfluidisin
motionwith uniformlow, subsonic
velocityaboveandparallelto a plane
rigidwall.A thin,rigid,semi-infinite
plateisparallelto thewallandthe
fluidflowspastits leadingedge.The radiatedsoundis calculated
for a
turbulenteddymodeledby a weakline vortexthat is allowedto convect
passively
pasttheleadingedgeof theplate.Accountistakenof thecontributionto the radiatedsoundfrom the disturbance
producedby the convectingvortexin theboundarylayersoneachsideof theplatebymeansof
Howe's( 1981) theoryof displacement
thicknessfluctuations(Proc. R.
Soc.London Set. A 374, 543-568), the strengthof suchdisturbances
beingfixedby a leadingedgeKutta condition.It is concluded
that the
predictedlevelof the radiatedsoundis substantially
reducedby these
boundarylayerdisturbances
relativeto whentheyareneglected.
The case
of the convection
of a frozentwo-dimensional
gustis alsoconsidered.
Examination
of theanalogous
problemof plane-wave
radiationfromthe
duct showsthat the presence
of displacement.
wavesenhancedboth the
far-fieldintensityin the ambientfluid and the reflectedfieldwithin the
duet.[Work supported
by ARE Teddington,
UK.]
2.'O5
L3. Further studieson pimel absorbers.B. S. Sridhara and Malcolm
J. Crocker (Department of Mechanical Engineering, Auburn
University, Auburn, AL 36849)
S27
J.Acoust.
Sec.Am.Suppl.1,Vol.82,Fall1907
ployed
tocalculate
impedances
atsuccessive
nodes.
Fora rigidsymmetric
N th-orderbranching
networkterminating
in 2N closed
branches,
a techniqueispresented
whereby
theopen-ended
inputimpedance,
anditscorresponding
resonance
condition,
canbeexplicitly
formulated
intermsof
thebranchlengthsandcross-sectional
areas,theangularfrequency,
and
theintegralharmonic
number.In thelow-frequency
range,theresonance
condition can be modified so as to facilitate volume estimation of the
branching
structures.
Experimental
studies
withrigidseeond-order
symmetricandasymmetric
branching
structures
arediscussed.
[WorksupportedbytheUniversity
of Connecticut
Research
Foundation.
]
2:35
IS. Surfaceroughness
effectson flow noise.OeorgeH. Christoph
(Martin Marietta Laboratories,1450S. Rolling Road, Baltimore,MD
21227)
TheCorcos
wallpressure
modelwasmodified
to incorporate
surface
roughness
effects.
Thelongitudinal
cross-spectral
density
partoftheCotcosmodelwasmodeledfrom roughwall datatakenfrom theliterature.
The wall pressure
frequency
spectrum
wasnondimensionalized
by the
wallshearstress
andboundarylayerdisplacement
thickness
andshownto
fit bothsmoothandroughwalldata.Theboundarylayerparameters
were
obtainedfrom a finite-difference
boundarylayer codedevelopedby the
authorto accountfor surfaceroughness
effectsby thediscreteroughness
approach[O. H. Christophand R. H. Pletcher,AIAA L 21, 509515(1983) ]. The blockage
of theroughness
height,shapeandspacingis
explicitly
accounted
forinthisapproach.
Flownoise
wascalculated
fora
varietyofroughness
elementheights
andspacings
in airandin water.The
114thMeeting:
Acoustical
Society
ofAmerica
$27
calculations
clearlyshowthatelementspacing
aswellasheightisimportant and that the viscoussublayerheight,not the boundarylayer thickhess,determines
theinfluenceof roughness
onflownoise.Thusroughness
is typicallymoreimportantin waterthanin air because
of the thinner
viscous
sublayer.Also,theeffectof transducer
sizeandviscoelastic
layer
thicknessare shownfor roughsurfaces.
2:50-3:00
Break
3:00
L6. Helicopter rotor speedeffectson farfield acousticlevels.Arnold
W. Mueller, Otis S. Childtess,Jr. (NASA Langley ResearchCenter,
M.S. 460, Hampton, VA 23665), and Mark Hardesty (McDonnell
DouglasHelicopterCompany,Mesa,AZ 85201)
The designof a helicopteris basedon an understanding
of manyparametersand their interactions.For example,in the designstageof a
helicopter,the weight,engine,and rotor speedmustbeconsidered
along
with the rotor geometrywhenconsidering
helicopteroperations.However,the relationshipbetweenthe noiseradiatedfrom the helicopterand
theseparameters
is notwellunderstood,
withonlya limitedsetof model
and full-scalefield test data to study.In general,thesedata have shown
thatreducedrotorspeeds
resultin reducedfarfieldnoiselevels.Thispaper
will reviewthestatusof a recenthelicopternoiseresearch
projectdesigned
toprovideflightexperimental
datatobeusedforfurtherunderstanding
of
helicopterrotor speedeffectson farfieldacousticlevels.Preliminaryresultswill be presentedrelative to testsconductedwith a McDonnell
DouglasHelicopterCompanymodel500Ehelicopteroperatingwith the
rotorspeedasthecontrolvariableovertherangefrom 103%N2 to 75%
N2 andthe forwardspeedmaintainedat a constantvalueof 80 knots.
3:15
L7. Fan noise and unsteady rotor forces. Wen-Shyang Chiu, Gerald
C. Lauehle, and D. E. Thompson (Graduate Program in Acoustics,
Applied Research Lab, PennsylvaniaState University, Box 30, State
College,PA 16804)
The noiseradiatedby a subsonic,axial-flowfan at its rotationalfrequencyandharmonicsisrelatedto thenonsteady
forcefieldcreatedat the
rotor blade/fluidinterface.This forcefield is highly dependenton the
time-invariantflow distortionsthat enter the fan. In this basicstudy,a
typicalcoolingfan usedin theelectronicandcomputerindustrywasinstrumented
withanunsteady
axialforcesensor.
Its outputisproportional
to the total unsteadyaxial forcecreatedby the rotor. The inflow field of
thefan wassystematically
distortedby placinga smallcylinderat various
positionsin theinlet plane.The nonuniform,three-dimensional
flowfield
enteringtherotorwasmeasured
by traversing
a miniaturefive-holepressureprobe.The total pressureoutputsfromthisprobecanberelatedto the
axial,tangential,andradialvelocityvectors.Fourierdecomposition
of the
inflowvelocitydata is coupledwith analysisto giveinformationon the
unsteady
rotorforceharmoniccontent.Theon-axissoundpressure
levels
weremeasured
andcomparedto coherentoutputpowerspectrainvolving
the unsteadyforcesensorandthe microphone.
Very goodcoherence
at
the discretetonesis observed.[Work supportedby IBM Corp.]
in-ductsilencer.Pressuredrop, fouling,and other problemsfrequently
associated
with silencers
canalsobeavoided.Previousattemptsat modi-
fyingan existingcentrifugalfan to controlnoisehaveoftenmet with
limitedsuccess.
To reducethe costof controllingbladepassage
tonesin
the community,modificationof the induceddraft (ID) fansat a power
plantwasevaluated.
Modeltestingwasconducted
for ten differentdesignsof thecutoffbarfor thecentrifugal
fan.Thenoisereductions
andfan
efficiencies
varied widely for six of the ten cutoffbars tested.The best
designgavebetternoisereductions
thanexpected
andhigherefficiencies
at usualsettings
ofthevariableinletvanes.The bestcutoffbardesignwas
installed (full scale) on one of the ID fans and fieldstested. The noise
reductions on the full-scale fan tests were better than obtained for the scale
modeltests.Resultsof both the modeland full-scaletestsare presented,
compared,and discussed.
3:45
L9. Frequencydomainanalysisof dipolesourcestrengthand correlation
area. David M. Yeager (IBM AcousticsLaboratory,P.O. Box 390,
C18/704, Poughkeepsie,
NY 12602)
The generation
andradiationof noisefroma rigidsurfaceimmersedin
a turbulentfiowfieldmaybe characterized
by the strengthof the dipolelike sourcesassociatedwith the normal surfacepressuresacting on the
fluidat thesurface,
andbytheregiS)ns
overwhichthese
sources
arepartially correlated.New frequency-domain
expressions
have beendevelopedfor the dipolesourcestrengthper unit area, basedon mean-square
pressure
andacousticintensity,and for the correlationarea.The equationsaresimilarto time-domain
expressions
developed
earlierIT. E. Sialdon,J. Acoust.Soc.Am. 53, 619-633 (1973) ]. The equationsshowthat
the correlationareacanbe thoughtof asa complexradiationefficiency
that is normalizedby its maximum value, the total area of the surface
immersedin turbulence.Both the correlationarea and dipole source
strengthper unit area reflectthe noisegenerationcharacteristics
of the
localturbulenceregionsandmutualinteractions
betweenregions.Results
of experiments
will bepresented
in whicha singleblade,removedfroma
rotatingcentrifugalair movingdevice,wasimmersedin a turbulentflow
field.
4:00
LI0. Scalemodelof an activenoiseredactionsystem.O. L. Angevine
(AngerincAcousticalConsultants,
Inc., P.O. Box725,EastAurora,NY
14052)
3:30
LB. Model and full-scale testing of a modified cutoff bar for a centrifugal
fan. Frank H. Brittain (Bechtel National, Inc., San Francisco, CA
94105) and David A. Nordstrand (Detroit Edison Co., Detroit, MI
84226)
Controllingcentrifugalfan noiseby modifyingthedesignof the fan is
very appealingbecausethe costcouldbe considerably
lowerthan for an
S28
d. Acoust.Soc.Am.Suppl.1, Vol.82, Fall 1987
Scalemodelinghasbeenusedoftenfor predictingacousticalproperties of architectural structures such as music halls. In this experiment, it is
an activenoiseattenuatingsystemthat ismodeled.By usinga scalefactor
of 8 or 16, testscanbeconductedon a tabletop simulatingthoseof a fullscalesystemat a distanceof 24 m. Sinceactiveattenuationismostsuccessful at frequencies
belowabout500Hz, thescalefrequencies
remainin the
audiblespectrum,and measurementdoesnot requirespecialequipment.
[Work supportedby EPRI and NMPC. ]
114thMeeting:AcousticalSocietyof America
S28
TUESDAY AFTERNOON, 17 NOVEMBER 1987
UMS 4 AND 5, 1:30TO 5:00P.M.
Session
M. Underwater
Acoustics
II: ArcticAcoustics
II (Prtcis-Poster
Session)
Robert Francois,Chairman
Applied
Physics
Laboratory,
University
of Washington,
Seattle,Washington
98195
ContributedPapers
Followingpresentation
of thepr•cis,posters
will beondisplayuntil5:00p.m.
1:30
M1. Ambientnoi•ein BaffinBay.Joseph
B. FarrellandGarryJ. Heard
(Defence
Research
Establishment
Atlantic,P.O.Box1012,Dartmouth,
The seaiceis modeledasa transversely
isotropicbrine-saturated
porousmedium,in accordance
with the modelproposed
by Schwarzand
Weeks (1977). The reflection and refraction of waves at the water-ice
This paperpresents
the resultsof ambientnoisemeasurements
taken
in BafflnBay in August-September
of 1986.Noisemeasurements
were
interfacearestudied.Thenumericalresultsobtainedin thisstudyindicate
thattheporosityof theicehasa noticeable
effectonthewavereflectivity.
Its effect,however,becomes
smallwhenthegrazingangleof theincident
wavebecomes
small.The existence
of a thin andporousiceskeletonlayer
takenin conditions
rangingfromopenwaterto iceberg-infested
water
on the icemediumfurtherreducesthe reflectivity.The reductionof reflec-
neartheedgeof packice.Differences
in thecharacterof ambientnoiseat
tivitybecomes
moredistinctasthefrequency
of theincidentwaveishigh.
Numericalresultspointoutthat,in additionto theporosity,theicelayer
thickness
is the mostdominantpropertyinfluencing
the undericewave
reflectivity.The calculatedresultsshowa qualitativeagreementwith the
Nova Scotia B2Y 3Z7, Canada)
theexperimental
siteswillbenotedanddiscussed.
Thefrequency
range
investigated
in thisworkwas10-1000Hz. Comparisons
will bemadewith
noisemeasurements
takenby DefenceResearchEstablishment
Atlantic
(DREA) in BailinBay in the 1970s.
in situ experimentalresultsby Yang and Votaw ( 1981).
1:34
1:42
M2. Super-resonantscatter under ice sheets and in full spaces.
Ivan Tolstoy (Knockvennie,Castle Douglas, SW Scotland) and
M4. A modal approachto Arctic noisemodelingwith implied vertical
AlexandraTolstoy (Naval ResearchLaboratory,Washington,DC
coherence.
R.B. Williams(NavalOceanSystemsCenter,
SanDiego,CA
20375)
92152)
Systems
of monapole
scatterers
interacting
throughmultiplescatter
may developnormal modes,i.e., true resonantbehaviorat certain frequencies(the equivalentsourcecoefficients
of eachscattererhavereal
poles).Thisoccurswhenthesinglescattercrosssections
arelargeenough
to givesignificantinteraction.Thishappensfor highlytunedscatterers,
e.g., gas-filledballoons,bubbles,and thin shellsin water, insonifiedat
frequencies
neartheircharacteristic
"bubble"frequencies.
Thiskind of
super-resonance
(SR) occurswhen the systemis at or near the interface
with an elasticmedium,e.g.,a thin elasticplate [I. Tolstoy,J. Acoust.
Sac.Am. 80, 282-294 (1986)]. Energytransportbetweenscatterers
is
thenmediated
byboundary
modes
excitedbythescatterers
actingaspoint
sources(e.g., the flexurewavesof a thin plate). The caseof two and three
bubblesystems
at an ice-wateror lucite-waterinterfaceisexplored,with
particularreference
to theparameters
ka, kl (k istheacousticwavenum-
ber,a thescatterer
radius,l thespacing
between
scatterers)
andtheplate
elasticconstants.
For a pair (doublet)the pressureamplificationre: the
free-fieldvalueis _•2 X 103for kl valuesassmallas0.5, with a directionality factorof 30: This is a passive,highlytuned,high magnification,
stronglydirectionalcompactarray ( •_A / 12size).A 30-Hz systemwould
Analyticformulasof the modalattenuation
coefficients
appropriate
for deepArctic under-iceconditions,
and modalenergypartitioningof
ambientnoisesources
areproposed.
Thesefunctionscanbeused,together
with variousassumed
spatialand temporaldistributionfunctionsto calculate various statistical ambient noisefunctions, such as vertical coher-
ence.Verticalnoisedata between15 and 50 Hz havebeenanalyzedfor
modelcomparison,usinga bandwidthof about 5 Hz. Thesedata show
thattheverticalcoherence
usuallyhasa sinx/x dependence,
withthefirst
zero crossingat one wavelength.Sometimes,
however,zero crossing
lengthsof morethan two wavelengths
are observed.Longercorrelation
lengthsare consistent
with muchof the noiseenergyradiatingfrom a
smallregion,althoughotherinterpretations
are possible.
Initial simple
modelcalculations
showagreement
with thedata.A strongnearbysource
of noisewill causethecorrelationto lengthen,whileseveralmoredistant
sources
supporttheonewavelength
zerocrossing
result.Initial sensitivity
calculations,
however,showthat the verticalcoherence
functionby itself
is not a goodvalidatorof the modelfunctions.Other statisticswill be
soughtto furtherexaminemodelvalidity. [Work supportedby NORDA
and NOSC 6.2 Arctic programs.]
consist
of twoballonsof 10-cmradiusnearan iceboundary,
witha discretesetof permissible
I valuesrangingfromabout5-20 m. Optimum
spacings
andmagnifications
dependupontheicethickness( _ 5 m). In an
acoustic
full space,energyexchange
betweenscatterers
is mediatedless
effectively
by volumewaves,and the scattercoefficient
polesvanish:
Bona-fideSR doesnot takeplace.Nevertheless,
strongpeaksmayoccur,
givingmagnifications
_ 103.Thisquasiresonant
behavior
isdiscussed
for
simpletwo-, three-,four-,andsix-element
planeandpolybedralconfigu-
rations.However,trueSRbehavior
isreintroduced
in full spaces
by partiallyblocking
selected
pathways
between
scatterers.
[Worksupported
by
ONR. ]
1:38
M3. A studyof reflectionandrefractionof wavesat the interfaceof water
and sea ice. C. H. Yew and X. Weng (Departmentof Aerospace
Engineering
and EngineeringMechanics,Universityof Texasat Austin,
Austin, TX 78712)
S29
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
1:46
MS. Under-ice scattering mechanisms.R. H. Mellen (PSI Marine
Sciences, New London, CT 06320) and P. S. Seheifele (Naval
UnderwaterSystemsCenter,New London,CT 06320)
Underwater acousticpropagationin the Artic Ocean is characterized
by a refractivesurfacechannelwith a roughboundary.Scatteringestimatesbasedon free-surface
theoryhaveprovenlow by morethan a factor
of 2 in forward-scatterlossand low by 20 dB or more in backscatter
strength.Failure to accountfor eitherattenuationor backscattering
indicatesthatimpedance
effects
mustbeinvolved.The icelayerismodeledas
a uniformelasticsolid.Perturbationanalysisshowsscatteringfrom slopes
aswellasdisplacements.
Displacements
producepistonlikereradiationin
addition to the usualvertical-dipoletype associatedwith free surfaces.
However,the "rocking"horizontaldipoleproducedby slopesis evidently
the dominantmechanismat the lower frequenciesand estimatesof both
114thMeeting:Acoustical
Societyof America
$29
attenuationand backscatter
strengthshowreasonable
agreementwith
experimental
datawhenincluded.[Worksupported
by NUSC/NL.]
or nosnowcover.Sincetheonlyicesurfaces
directlyexposed
to air in the
vicinityof theexperiment
werethe verticalsidesof largeblocksof icein
pressure
ridges,it is hypothesized
that the crackscouldhaveoriginated
there.
1:50
M6. Sound ubsorl•tionin Arctic regions.R. H. Mellen (PSI Marine
Sciences,
NewLondon,CT06320),P.S. Scheifele,
andD. G. Browning
(Naval UnderwaterSystemsCenter,New London,CT 06320)
Soundabsorption
in seawater
involves
relaxations
of magnesium
sulfate,boricacid,and magnesiumcarbonate.Absorptionvarieswith both
regionand depth, due mainly to the pH dependence
of the boric acid
relaxation.The nominalseawaterpHrangeis7.7-8.3 andmagnitudes
can
varyovernearlya factorof4 at lowfrequencies.
A globalmodelforWorld
Oceanpredictionhasbeendeveloped,
employingcontourchartsof thepH
factorat severaldepths.Profilesfor integration
of lossalongraypathsare
generatedby algorithm.ThepH rangein the Arctic isnominally8.0-8.3
andsimilarcontourchartsareprovidedfor thepH factorin theseregions.
Althoughlong-rangepropagationis generallylimitedby under-icescattering,absorptioncan be the dominantlossmechanism
underice-free
conditionsand for rangeslessthan 50 km at sonarfrequencies
with an ice
cover.Predictedabsorptionspectraare presentedand comparedwith the
limiteddataavailable.[Work supported
by NUSC/NL.]
1:54
M7. A bistatic, high-frequency,under-ice, acoustic scattering model.
Garner C. Bishop (Bldg. 679, Code 8211, Naval Underwater Systems
Center, Newport, RI 02841)
A modelhas beendevelopedto evaluatethe scatterproducedby a
high-frequency
acousticpulseoriginatingfrom an arbitrarily located
source,incidentontheunder-icesurfacecharacteristic
of packiceregions
of the interiorArctic and detectedby an arbitrarilylocatedreceiver.Measured,two-dimensional,
under-ice,acousticprofiledata and severalem-
piricalresultsthat relatevariousgeometric
parameters
of thelargescale
2:02
M9. An experimentnlstudyof the coherentunder-icereflectivityof sound
in the GreenlandSeaMarginal Ice Zone (MIZ). PatriciaL. Gruberand
RonaldL. Dicus (Code5120,Naval ResearchLaboratory,Washington
DC 20375)
The coherentcomponent
of acousticunder-ieereflectivitywasinvestigatedasa functionof frequency
andgrazinganglein theMIZ. Measured
reflectivitywascomparedwith scatteringtheorypredictionsto test the
hypothesis
of ridgescatteringdominancein the MIZ. Explosivesource
acousticsignalswerereceivedona verticalarray,duringtheMarginalIce
ZoneExperiment(MIZEX 84), anddeconvolved
to separatethe direct
and ice-reflected
arrivals.Ice-reflectedsignalsreceivedon individualhydrophonesat differentrangesand depths,and on differentdays,were
alignedin timeandcoherently
ensemble
averaged
withina moving10-deg
grazinganglewindow.The resultingreflectivitywasfoundto decrease
with increasingfrequencyfrom 64-256 Hz and with increasinggrazing
angle from 12-35 deg. Comparisonwas made with predictionsfrom
smoothelasticplatetheory,perturbationtheoryfor a roughpressurereleasesurface,perturbationtheoryfor a roughelasticsurface,Twersky
theoryfor hemispherical
bosses
on a plane,andTwerskytheoryfor infinite,semielliptical
cylindersona plane.The Twerskytheoryfor semielliptical cylindersgave a significantlybetter fit to the data than the other
theories.This suggests
that, althoughtheunder-icetopographymaybea
gooddeal morecomplicated,scatteringmay, nevertheless,
be dominated
by remnantsof elongated
pressure
ridgekeels.Remotesensing
data,taken
duringtheexperiment,showedthat theicecoverwasprimarilycomposed
of smallfloes( < 200 m in diameter).Laserice-surface
heightmeasure-
mentswereanalyzedto obtainthepressure-ridge
sail-height
distribution.
The Twerskytheorymodelinggavepredictionswithin 1 dB of the measuredmeanreflectivitywhena ridgekeel-to-sailratioof 6.5 wasassumed.
under-icerelieffeatures,e.g.,icekeelsare usedto constructa three-dimensional,bimodal,under-icesurfacemodelconsistingof first-yearice keels
andslopingflat iceregions.A first-yearkeelis modeledasan ensemble
of
randomlyorientediceblockson a planarsurfaceinclinedat someslope
anglewith respectto a horizontalplaneat sealevel.Iceblocksaremodeled
aslayered,viscoelastic,
rectangularsolids.A regionof flat ice is modeled
as a smoothplanar surfacewhoseslopeangleis lessthan somearbitrary
minimumkeel slopeangle.The Helmholtz-Kirchhoffintegraland the
Kirchhoffapproximation
are usedto evaluatethe scatteredfield.Time is
partitionedinto binsand then,beginningat the bin corresponding
to the
timethe scatteredfieldof eachscatteringfacetarrivesat the receiver,the
scatteredfieldis addedcoherentlyin all binsspanningthe temporalduration of the incidentpulse.The resultingscatteredfield time seriesis used
to calculatethe corresponding
reverberation
time series.Modeledreverberationlevelsarecomparedwith measured
levelsfor severalArctic sites
and modestagreementis obtained.
Observation
of
thermal
ice.crnekinR
MIO. Attenuation of sound through laboratory grown saline ice. K.
C. Jezek (U.S. Army Cold Regions Research and Engineering
Laboratory,and Thayer Schoolof Engineering,Dartmouth College,
Hanover, NH 03755), T. K. Stanton (Department of Geology and
Geophysics,Universityof Wisconsin,1215 W. Dayton, Madison,WI
53706), and A.J. Gow (U.S.A. Cold RegionsResearchand Engineering
Laboratory, Hanover, NH 03755)
Attenuationof acousticwavestransmittedthrough salineice was
studiedin situasiceformedin a large,outdoorpool.Amplitudeof sonar
pings (50-800 kHz) transmittednormal to the ice sheetsurfacewere
measuredafter passingthrough ice about 18 cm thick and having an
averagesalinityof about4 paRRs
per thousand.Columnarcrystalsin the
body of the ice sheetand a fine, dendriticstructurenear the baseof the ice
sheet(dendriteswere about0.5 mm thick) characterizethe ice as being
1:58
MS.
2:06
nearlyidenticalto young,uncleformed
seaice foundnaturallycovering
in
the
Arctic
Basin.
the polaroceans.Additionalmeasurements
wereperformedon newly
P. Zakarauskas (Defense Research Establishment Pacific, FMO,
Victoria, British Columbia V0S lB0, Canada)
grownsalineiceabout3 cm thick.Measuredattenuations
throughthe 18cm-thickicerangedfromabout20 dB at 50 kHz to 80 dB at 420 kHz. For
It is now well knownthat thermalice-crackingis a major contributor
to under-iceambientnoisein certainregionsof shore-fast
iceduringwinter andspring[A. R. Milne, J. Geophys.Res.77, 2177-2192 (1972) ]. A
reportisgivenhereof an observation
of thermalicecrackingmadeby the
DefenseResearchEstablishmentPacific over polar pack ice during the
springof 1987.The numberof events,ascountedby a time-domainkurtosismethod,is showedto followthe temperaturechangesof the air very
closely. Thermal ice-crackingwas the dominant ambient noise source
duringtheperiodsof rapidair cooling.For thermalice-cracking
to occur,
threeconditionsmustbemet:low temperature,low ice salinity,and little
paredto about40 dB for the 18-cm-thickice). That this represents
an
absorption
of theacousticwaveby theiceisevidenced
bytwo otherobservations:first, a low reflectioncoefficientmeasuredon newly grown ice
(about0.04 at 188kHz); second,measurements
of scatteredenergyback
$30
J. Acoust.Soc. Am.Suppl.1, Vol.82, Fall 1987
the 3-cm-thick ice, total attenuation at 188 kHz was about 12 dB (com-
into the transmitting region showedlittle redistribution of energy into
nonspecular
directions.Basedontheobserved
decrease
ofattenuationper
unit thicknessof ice, significantabsorptionis attributedto the lower,
porousand permeableportionsof the ice. Presumablythe importantabsorptionmechanisms
are associated
with the pureicedendritesand alternatingplanesof brinepockets.
114thMeeting:AcousticalSocietyof America
$30
2:22
2:10
MII.
Elements of Arctic surface scatter: Part III,
the head wave.
MI4. Sea ice reflectioncoefficientestimatesat low frequency.George
HermanMedwin,Ken J. Reitzel,
=! andMichaelJ. Browne(Physics
R. Giellisand T. C. Yang (Naval ResearchLaboratory,Washington,
Department,NavalPostgraduate
School,Monterey,CA 93943)
DC 20375-5000)
Laboratoryscalemodelstudieshavethe virtueof revealingthe detailedbehaviorof the elementsof scatterfrom a complexice field.Previousmodelstudieshavedemonstrated
thequasidipole
radiationpattern
of low-frequency
scatterfroman openlead.It hasalsobeenshownthat
leadsand ridgesbackscatterprincipallyfrom a one wavelengthextent
neartheleast-timeinterceptof theradiationfroma pointsource.At this
time, evidenceis presentedthat mode conversiongeneratesa compressionalwavethatpropagates
parallelto thesurfaceof theice.Thismodeis
driven,andwill radiateintothewater,at thecriticalangle.The reradiated
sound,anexampleof a headwave•causes
a significant
precursorto appear
beforethe specularreflectionfrom the ice canopy.In agreementwith
Resultsof a seaicereflectivityexperimentconducted
at theFRAM IV
icecampwill bepresented.
A verticalarraywith27 receivers
at depths
rangingfrom 30-960 m wasemployed.Implosivesourcesat various
depths(30-120m) weresetoffat a rangeof 1145m fromthereceivers.
Analysisof directandreflectedpulsesat the receivers
resultedin reflectioncoedticient
estimates
at frequencies
in the 50 Hz to I kHz rangefor
reflection
angles
between
6' and60'. Theresultswill becompared
with
previous
data[T. C. YangandC. W. Votaw,1.Acoust.
Soc.Am.70,841851 ( 1981) ] and modelcalculations.
theory,
themeasured
headwaveamplitude
isproportional
to
XL -•t2 wherek is the wavenumber
in the water,x is the horizontal
range,andL isthepathlengthin theice.[ WorksuppoRed
by theOfficeof
NavalResearch.]
*•OceanAcoustics
Associates,
4021Sunridge
Rd.,
Pebble Beach, CA 93953.
2:26
MI5. Two numericalmodels•one simplistic,the othersophisticated-applied to under-ice acoustic propagationand scattering. Stanley
A. Chin-Bing (Naval Ocean Researchand DevelopmentActivity,
Numerical Modeling Division, NSTL, MS 39529-5004) and Joseph
E. Murphy (Departmentof Physics,Universityof New Orleans,New
Orleans, LA 70148)
2:14
M12. Laboratoryscaleinvestigationof the amplitudeandphaseof signals
reflected from sea ice ridges. T. McLanahan (Naval Air Systems
Command,Washington,DC 20361-5220), O. I. Diachok, and S.
C. Wales (Naval ResearchLaboratory,Washington,DC 20375)
Acousticreflectivityfrom plasticmodelsof seaice ridgeson a thin
platewereinvestigated
for 0.67< ka < 6 (wherek is thewavenumber
and
a isthemeanridgedepth).Modelswereconstructed
of lucite,whichhas
acoustic
velocities
consistent
with analyticallyestimated
velocities
of sea
iceridges,andof"fast cast,"a materialwith muchlowervelocities.
For
ka > I measurements
from randomlyorientedandparallelluciteandfast
castridgesona thinplateandonan infinitehalf-space
werenearlyidentical,andin goodagreement
withTwerskytheoryprediction.
At thelowest
frequency,
ka ---0.67,andatgrazingangles
lessthan20ø,measured
reflection losses
weresignificantly
greaterthanpredictions:
twiceaslargefor
randomlyorientedluciteridgeson a thin plate.The phasechangeupon
reflection
wasstrongly
dependent
onthematerialproperties
of theridges
and their orientation.Resultsfor randomlyorientedluciteridgeswere
foundto be reasonably
consistent
with previously
reportedinferences
of
reflection
lossandphasebasedonmatchedfieldprocessing
ofdatarecorded on a largeapertureverticalarray in the Arctic [Livingstonand Dia-
Many factorsmake modelingunder-iceacousticpropagationand
scatteringdifficult:Interfacesare roughwith randomprotusions;
ice is
acousticallypenetrable;little data exist;few validatedmodelsexist;frequencies
of interestrangefromthehertzto thekilohertzregion.Thusno
one modelappearssufficientfor all conditions.With this in mind, two
under-iceacousticmodelsat oppositeextremesarc examined.One model
is simplistic,usingKirchhoff approximation,ice reflectioncoefficients
[S. A. Chin-Bing,J. Acoust.Soc.Am. Suppl.1 78, S57(1985)] andrms
roughness.
Model resultscomparefavorablywith high-frequency
measurementsfrom a flat cylindricaliceblock.Implicationsare that simplistic modelsmaybeusefulin generatingsyntheticunder-iceacousticdatato
augmentsparseexperimental
databases.The othermodelissophisticated
in thatit isa full-waverange-dependent
acoustic
propagation
modelbased
on the finiteelementmethod[J. E. Murphy and $. A. Chin-Bing,J.
Acoust.Sac.Am. Suppl. ! 81, S9 (1987)] and appliedto an under-ice
surfacesimulatedbyfractalssuperimposed
onan icekeelrepresentation.
Numericalresultsare presented
for this low-frequency
model. [Work
supportedby ONR/NORDA. ]
2:30
chok,J. Acoust.Soc.Am. Suppl. 1 81, $85 (1987) ].
M 16.Low-frequency
propagation
acrosstheEastGreenlandandFrontal
Zone:Depthdependence
of transmission
loss.LeonardE. Mcllberg,D.
N. Connors,D. G. Browning,G. Botseas
(Naval UnderwaterSystems
2:18
Center,Newport,RI 02841), and O. M. Johannessen
(Geophysical
Institute,Universityof Bergen,Bergen,Norway N-S014)
MI3. Low-frequency
transmission
lossmodelingin the Arctic using
measuredmode attenuation coefficients.T. C. Yang (Naval Research
Laboratory,Washington,DC 20375}
Low-frequency
transmission
lossin theArcticcanbeeffectively
described
by thereflection/scattering
lossat theice-waterinterface
dueto
theupwardrefractive
sound-speed
profile;thesoundfieldthat interacts
withthebottomisquicklyattenuated
astobeunimportant
at longranges.
Variousmodelsfor the reflection/scattering
losshavebeenproposedin
theliteratureandcanbeshownto agreewith singlehydrophone
databy
adjusting
theiceroughness
or otherparameters
in themodel.However,a
criticaltestof the modelpredictions
hasto be conducted
usingvertical
In a previous
paper[ L. E. Mellbergeta!.,J. Acoust.Soc.Am. Suppl.1
78, S71( 1985) ] thedirectionaldependence
of acoustic
modesacrossthe
EastGreenlandFrontalZonewasexamined.
However,fora givensource
andreceiverdepth,transmission
losscanbedueto a combination
of these
directionallydependent
acousticmodes.By changingthe depthsof the
sourceand receiver,the directionaldependence
of the transmission
loss
maybechanged,
in somecasesto theextentof causinga reversalin the
dependency.
Resultsaregivenfor a seriesof sourceandreceiverdepths
locatedat variousrangesrelativeto thefrontalzone.[Work supported
by
NUSC and ONR. ]
arraydata,sincethedepthdependence
of thesoundfieldprovidesa more
meaningful
measurement
of the angulardependence
of the reflection/
scattering
loss.In thispaper,theangularandfrequency
dependence
ofthe
reflection/scattering
coefficients
wasinvestigated,
basedon themodeattenuationcoefficients
previously
deducedfromverticalarraydata.It was
found that the measuredreflection/scattering
losswas larger than most
modelpredictions
usingrealisticiceroughness
parameters.
A transmissionlossmodel,basedon a simpleparametricfit to the reflection/scattering data,wasshownto agreewell with previouslypublisheddata.
S31
J.Acoust.
Soc.Am.Suppl.
1.Vol.82.Fall1987
MI7. Relativescatteringfromdry cracks,iceridges,andleads.Jacques
R. Chamuel(Sohoquest/Advanced
Ultrasonics
Research,
P.O.Box153,
WellesleyHills, MA 02181) andGary H. Brooke(DefenceResearch
EstablishmentPacific, FMO, Victoria, British Columbia V0S lB0,
Canada)
114thMeeting:
Acoustical
Society
ofAmerica
S31
Little is knownaboutthe characteristics
of dry cracksin Arctic seaice
and their effecton low-frequency
underwateracousticwavesinteracting
withtheice.Ultrasonicmodelingresultsarepresented
showingthe relativescatteringfromdry cracks,leads,andridgesin floatingplatesboundinga longshallow-water
waveguide.
Backscattering
fromsolidridgesand
ridgeswith internalcracksrevealthepotentialimportance
of dry cracks
on low-frequency
transmission
lossprediction.In modelswith a large
TUESDAY
AFTERNOON,
17 NOVEMBER
numberof rectangular
ridges,greattransmission
losses
wereobserved
at
frequencies
nearlycoinciding
with twicethe ridgewidth.The articlefocuseson multiplescattering
frominfinitelylongshallowparallelcracks,
wherethecrackdepthismuchsmallerthanthewavelength.
For a given
numberof cracksor ridges,theattenuation
of lowfrequencies
propagatingin thewaveguide
isgreatlyaffected
by theirspatialdistribution
along
thewaveguide
boundary.[Work supported
by DREP andONR•]
1987
POINCIANA
ROOM, 2:00 TO 4:15 P.M.
SessionN. ArchitecturalAcousticsII: AcousticalDesignof RenovatedPerformanceFacilities II
David Lubman, Chairman
DavidLubmanand Associates,
14301MiddletownLane, Westminster,
California92683
Chairman's
lntroduetionw2:00
Invited Papers
2.'O5
N1. The imimetof Playhouse
Squareon the resurgence
of Cleveland.LawrenceWilker (PlayhouseSquare
Foundation, 1501 Euclid Avenue, Suite 810, Cleveland,OH 44115)
Cleveland,Ohio, wasa city in economicdistresswhena groupof farsightedcitizensand local officials
decidedto developa downtownculturalcenter.Lackingthe fundsfor a 300 milliondollarproject,it was
decidedto renovatea three-roomvaudeville/filmthefitrecomplex,knownasPlayhouse
Square.Onetheatre
wasdesignated
asa drama/dance/chamber
orchestra
facility,anotherasthehomeof theCleveland
Operaand
BalletCompanies,
andthe third asa venuefor popularentertainment.
The papertracesthe historyof the
projectandits impacton the resurgence
of Cleveland.
2:30
N2. New theatresfor old. Norris Strawbridge(Borrelli FrankelBlitsteinSasakiAssociates,
Inc., 7000 S.W.
62nd Avenue, Suite 520, Miami, FL 33143)
TheMiamiBeachTheatrefor thePerforming
Arts,recentlyrenamed
TheJackieGleasonTheatre,began
itslife asa multipurpose
theatre/sports
facility.In themid-1960's
a combination
of communityneedsanda
decision
byJackieGleason
to broadcast
histelevision
programs
fromMiamiBeachresulted
in a renovation
of
the hall asa performingarts/televisionstudiovenue.Althoughthe theatrelackedcertainamenities,it fostered
thegrowthofoneof thelargestooncert/opera/dance
series
in Americaandhasbecome
thehomefora 26-week
Broadway
showseason.
Recognizing
theinherent
problems
in thefacility,theCity recently
commissioned
a
second
renovation
tobringthespace
uptocontemporary
acoustic
andtheatre
standards.
Thepaperdiscusses
themethods
usedto developan architectural
programfor therenovation
andthesolutions
developed
by the
designteam to attaindesiredgoals.
2:55
N3. Renovation
of the OrpheumTheatre,Vancouver,Canada.Ewart A. Wetherill (Wilson,lhrig and
Associates,5776 Broadway,Oakland,CA 94618)
Despite
theever-increasing
costofperformance
facilities,
thedesign
andconstruction
ofa completely
new
auditorium
ispreferred
withremarkable
consistency
tothealternativ.e
ofrenovating
or remodeling
anexisting
unused,
orunder-used,
auditorium.However,thereuseofanexistinghahmayyield--in additionto substantial
costsavinga---such
advantages
asprimelocation,existingsocialrecognition,
andhistoricalsignificance.
This
paperreviewstheremodeling
of theOrpheum,originallya vaudeville
theatre,fromcinematoconcerthallasan
alternativeto its conversion
to severalsmallcinemas.In mostrespects,
the renovationhaspreserved
the
originalarchitectural
characterwhileattaininga criticallyacclaimed
performance
facility.
$32
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
114thMeeting:Acoustical
Societyo!America
$32
3:20
N4. Acoustics
of thenewFllcoeCenter,Wolf Trap FarmPark for thePerformingArts.ThomasR. Hotrail
andRein Pirn (BBN Laboratories,
Incorporated,
125CambridgePark
Drive,Cambridge,
MA 02140)
To replace
theoriginalFileneCenterthatwasdestroyed
byfire,a newstructure
wasdesigned
andbuiltin a
scant2 years( 1982-84). Like itspredecessor,
the 3800-seatcoveredhouse,with an additional3000seatson the
lawnbeyond,servesasa summerhomefor theNationalSymphonyOrchestraandcatersto manyotherforms
of artisticproduction.Undera mandateto rebuildthestructureasit hadbeen,the acoustical
optionswere
limited.Knownproblems
suchasdiscreteechoesoff the highceilingwereeliminated.Stageacoustics
were
greatlyimproved
by incorporating
a totallynewshell.Mostsignificantly,
thecenterwasequipped
withstateof-the-artsoundsystems,
includinga sophisticated
enhancement
systemthat coversthe under-balcony
areas.
The principalacousticalcharacteristics
of thecenterarediscussed
andthe soundsystems,
their purpose,and
their operationalparametersdescribed.
3:45-4:15
Panel Discussion
TUESDAY AFTERNOON,
17 NOVEMBER
1987
TUTTLE
Session O. Structural Acoustics and Vibration
NORTH ROOM, 2:00 TO 4:05 P.M.
II: Fluid-Loaded
Structures
Albert J. Tucker, Chairman
Officeof Naval Research,
MechanicsDivision,Code1132SM,800 North QuincyStreet,/trlington,Virginia22217
Chairman's
Introductlonm2:00
ContributedPapers
2:05
O1. Simulated wave-vector filtering of impact-generatedflexural wave
disturbanceson a finite thin-walled cylinder. Allan D. Pierce, Jerry
H. Ginsberg, and Gary P. Schwaiger (School of Mechanical
Engineering,
GeorgiaInstituteof Technology,
Atlanta,GA 30332)
The authorshaverecentlyundertakena theoreticalsimulationof ex-
perimentssimilarto thoseperformedrecentlyat NRL by Earl G. Williamsand his colleagues,
in whicha submerged
cylinderis transiently
excitedandnormaldisplacements
areinferredusingthegeneralized
nearfieldacoustical
holography(GENAH) technique.
In thepresentpaper,
Previous
workby theauthorwith PierceandGinsberg[J. Aeoust.
Sac.Am. Suppl.1 79, S35(1986)] usinga variationalformulalion
has
beenextended
to axisymmetric
bodiesin a generalstateof axisymmetric
vibration.
A Rayleigh-Ritztechnique
is usedto calculate
theacoustic
pressure
distribution
onthesurface
of axisymmetrically
vibrating
finite
cylinders.
Thecomputed
surface
acoustic
pressure
andthegivennormal
surfacevelocityarethentakenasinputsintoanintegralrelationfordeterminationof the farfieldradiationpatterns.Differenttrial functionsare
the cylinderis modeledas a thin-walledshell with rigid immovableend
employed
in theexpansion
fortheunknown
surface
pressure
andresults
arecompared
witheachother.It isdemonstrated
thatthecomputational
solutions
converge
muchfastertowardthecorrect
answers
ifoneincorporateshisphysical
insightandpriorknowledge
intotheconstruction
of
capsandwiththeendconditions
takenasbeingthatof simplysupported.
A shortdurationpoint forcef(t) is appliednormallyto the surfaceand
oneseeksto describe
theresultingnormaldisplacement
fieldusinga highfrequency(and shortwavelength)asymptotictheoryof propagating
and
evanescent
flexuralwavepulseson a curvedplate.Fluid loadingis taken
putedusingRogers'
SHll'program.[Worksupported
byONR.]
intoaccountapproximatelywith modifications
derivedusingthe assumption that the flexuralwavelengthsare short comparedto the lengthand
radiusof the cylinder.One asksfor the time and surfacepositiondependenceof the normal surfacedisplacement
within a local regionof the
cylindricalsurfacebeforeand after a simulatedwavevectorfilteringhas
beenapplied.The filteringprocessis suchthat one seeksto isolateonly
that contributionfrom a narrowfrequencybandand from a localized
regionof wavenumber
space.The exercise
isintendedto demonstrate
that
onecan isolateand followtravelingwaveletspropagating
awayfrom the
source,spiralingaroundthe cylinder,and undergoingsuccessive
reflectionsat theendcaps.IWork supportedby ONR. ]
2:20
02. Numerical implementation of variational techniques for sound
radiation from axially and radially vibrating finite cylinders. Xiao-
Feng Wu (School of MechanicalEngineering,Georgia Institute of
Technology,Atlanta, GA 30332)
S33
J. Acoust.Soc. Am. Suppl.1, Vol. 82, Fall 1987
admissible
trial functionsfor the unknownsurfacepressure.
Examples
studiedincludefinitecylindersvibrating,respectively,
in theradialdirectionandaxialdirectionasa rigidbody.Numericalresultsagreewellwith
thosepreviously
published
by Copicyandby FenIonandwiththosecom-
2:35
03. Impulseresponse
of a continuously
ribbedpanel.G. Maldanikand
L Dickey(David TaylorNavalShipResearch
andDevelopment
Center,
Bethesda. MD 20084)
The impulseresponse
functionof a uniformpanelimmersed
in a uniform environmentis assumedknown.The modificationin this impulse
response
functiondueto theattachment
of identicalandregularlyspaced
ribsisderived.The mannerof negotiating
thismodifiedimpulseresponse
function from the discretenessto the continuum of ribs is discussed. The
negotiationrevealsthe criteria that needto be satisfiedfor uniformly
lurepingtheribsin thepanel.Whenthecriteriaaresubstantially
satisfied,
theribbedpanelbecomes
essentially
a uniformpanel.The ribsarethen
accounted
for by lumpedmodification
of the uniformimpedance
of the
unribbedpanel.
114th Meeting:AcousticalSocietyof America
S33
04. Vibration of a plate with distributed structural stiffness.
Mauro Pierucci(DepartmentofAerospaceand
Engineering
Mechanics,
SanDiegoStateUniversity,SanDiego,CA 92182)
wavenumber
and the wavenumber
the scheme for finite boundaries and to formulate interface conditions
with an acousticfluid. Qualitativeand quantitativeresultsare presented
In mostanalysesof plates,only two typesof platevibrationshave
receivedwideattention:homogeneous
platesandplateswith discretediscontinuities.In thiswork,thestructuralinhomogeneity
hasbeenselected
to becontinuous
anddistributed.The plateis assumedto beinfinite.The
stiffness
hasbeenassumedto vary in a sinusoidalmanner.The resulting
differentialequationhasbeensalvedby theuseof Fouriertransformsand
the solutionin the wavenumber
spaceis presented.
The plateadmittance
is a function of the structural
to theentirebody.The dispersion
spectrumexhibitstheclassical
Brillouin
structureof stoppingand passingbands.Even thoughFloquet'stheory
appliesessentially
to infiniteregions,it is nevertheless
possible
to adapt
for harmonicmotionsof two geometries,
namely,a layeredhalf-space
withan overlyingacoustic
fluidanda submerged
infinitelaminatedplate.
Specialattentionis paid to the energypartitionbetweenthe layeredsolid
and the fluid for the completerangeof frequencies.
[Work supportedby
ONR. ]
of the
distributedinhomogeneity.
The resultsfor the in vacuoand the fluidloadedplatesarepresented.
In theveryshortandtheverylonginhomogeneitywavelengthlimits,theeffectof thestructuralinhomogeneity
is very
weak at all structural wavenumbers. The main contribution to the struc-
tural admittanceis presentwhenthe valueof thestructuralinhomogeneity wavenumberis closeto the coincidencestructuralwavenumber.For
the in vacuoca•es,it is shownthat the effectof the inhomogeneityis
limitedto valuesof thestructuralwavenumber
equalto thecoincidence
wavenumber
plusor minusan integralmultipleof the inhomogeneity
wavenumber.
3:05
05. Resonantresponseof elastically supported,fluid-loadedplates.
JamelHammoudaand CourtheyB. Burroughs(Engineering
Science
and MechanicsDepartment,The PennsylvaniaState University,
UniversityPark, PA 16802)
An analyticmodeloftheresponse
offiniteplatessimplysupported
on
two opposing
edgesandelastically
supported
on theotheredgesis derived.Transverse
shearandrotaryinertiain theplateandadjustable
stiffheSS
constantsin theelasticsupportsare includedin the model.The elastic
3:35
O?. Accelerometerarray ns a meansto evaluate structural anderw•ter
sound.D. Brenot (Department of Physics,Oncra, BP ?2, 92322
Ch•tillon Cedex, France)
The turbulentboundarylayer 1ow-wavenumber
component,an importantsourceof underwaterstructureencitation,cannotbe precisely
determined.Nevertheless,
the resultingwall accelerations
can be accuratelymeasured.
Theyalreadycontainthecouplingwith thefluid,avoid
thecomputationof the structuralmotion,andallowdirectcalculationof
the farfieldnoiseradiatedby the vibrationitself:The singlefrequency
farfieldnoiseradiatedin a givendirectionby a baffledpanelcomesfrom
onecomponentof the wavenumberacceleration
spectrum,and only one
( seeM. C.Junger
andM. P6rulli,Elements
d '•4coustique
Physique,
p. 59).
Thiscomponentmaybeobtainedexperimentally
byperformingtheFourier transformof the wall acceleration
usingan accelerometer
array.An
underwater
experiment
isshownona 3-ram-thickpanelwitha 5 X 5 acceIcrcmeterarraymatrix (Ax = 70 min. Ay = 60 ram) andona thickcylinder (radius:i m; length:12 m) with a 10-accelerator
lineararray.The
paraboliclawsbetweenwavenumber
and frequencyclearlyappearand
are quite typicalof eachelement.Thesemeasurescan thus be usedto
estimatetheir radiation efficiency.[Work supportedby DCN/CERDAN. i
supportstiffness
constantsare adjustedto simulatesimplysupported,
clamped,
andfreeboundary
conditions,
andtheresultsarecompared
to
published
results.The variationof resonant
frequencies
with the stiffnesses
of theelasticsupports
isshown.Theeffectof fluidloadingonthe
resonant
responses
of theelastically
supported
plateis presented.
3:50
08. New approachesin vibroaconsticmeasurement
systemdesign.
Joseph
A. Clark andPaul M. Honke(David W. TaylorNavalShip
Researchand DevelopmentCenter,Bethesda,MD 20816and Catholic
University,Washington,
DC 20064)
3:20
Recentadvances
in measurement
instrumentation
andin computer
06. Dynamicresponse
of submerged
layeredcomposites.
Arthur Braga
andGeorgeHerrmann(Divisionof AppliedMechanics,
Departmentof
MechanicalEngineering,StanfordUniversity,Stanford,CA 94305)
hardwaresuchas morefully programmable
signalconditioners,
faster
data convertors,
processors
and otherhandlers,higherresolution
displays,andlargermemories
invitethedevelopment
of newvibroacoustic
measurement
approaches.
In thistalk,thedesign
andimplementation
ofa
Thedynamicinteraction
between
elasticandhomogeneous
two-phase
periodicallylayeredbodiesand a surroundingacousticfluid has been
studied.The plane-strain
elastodynamic
behaviorof the compositehas
beenmodeledonthebasisofFloquet'stheoryforperiodicstructures.
This
approach
consists
ofsolvingtheequations
of motionfora cellthatrepeats
periodically,andthenapplyingFloquet'stheoremto extendthe solution
newsystem
for measuring
radiatedandself-noise
pathsassociated
with
complex,large-scale,
immersedstructures
will be described.
New approaches
willbepresented
in thecontextofsoftware
developed
or utilized
to achieveimprovedperformance
of control,processing,
display,and
analysis
functions.
Advantages
of thenewapproaches
forstudies
ofmore
S34
J. Acoust.
Soc.Am.Suppl.1, Vol.82,Fall1987
subtleand complexvibroacoustic
effectswill be discussed.
114thMeeting:
Acoustical
Society
ofAmerica
S34
WEDNESDAYMORNING,18NOVEMBER1987
UM AUDITORIUM,8:10TO 11:45A.M.
Session
P. SpeechCommunication
III: Recognition
Jay G. Wilpon, Chairman
/1T&TBellLaboratories,
Murray,Hill, NewJersey
07974
Chairman's Introduction--8:10
ContributedPapers
8:15
PI. Performance
benchmarks
for isolatedwordrecognition.
Lawrence
R. RabinerandJayG. Wilpon(AT&T BellLaboratories,
MurrayHill,
NJ 07974)
The performance
of isolated
wordspeech
recognition
systems
has
steadily
improved
overtimeasmoreislearned
abouthowtorepresent
the
significant
events
in speech
andhowtocapture
these
events
viatraining
algorithms.
In particular,
algorithms
based
onbothtemplate
matching
andhidden
Markovmodels
(HMMs) havebeendeveloped
thatyieldhigh
accuracy
onseveral
standard
vocabularies
including
thetendigits(zero
tonine)andthesetofletters
oftheEnglish
alphabet.
Results
arepresentedherethatshowtheeffectofanalysis
parameters
(e.g.,framesize,frame
rate) on recognition
performance
for a speakertrainedsystemand the
performance
of both templateand HMM-basedrecognizers
(both
speaker
trainedandspeaker
independent)
onthedigitsandthealphabet
Techniques
thatautomateall or partsof thisprocess
arethereforehighly
desirable.Two approaches
havebeenused:the generationof pronunciation networksfrom baseforms
by applicationof phonological
rulesand
theabstraction
of suchnetworks
fromtranscription
data.Thispaperdescribes
a semiautomatic
procedurefor derivinglexicalmodelsfrom manual phonetictranscriptions.
The algorithmusesa feature-based
distance
thatspecifyalternatepronunciations
for words.The paperdescribes
the
results
ofconstructing
lexicalnetworks
fora 1000-word
vocabulary,
using
a corpusof 10000 work tokens.It shouldbe notedthat the technique
metric
to
align
differe
pronu
and
prod
pho
ne
describedhereis not restrictedto manualtranscriptions,
but can be extendedto automatictranscription
suchastheoneproducedby a front-end
componentof a speechrecognitionsystem.
vocabularies.
9:00
P4. A wordclassification
methodfor therecognition
of Japanese
froma
largevocabulary.
KazunagaYoshida(C&C Information
Technology
Research
Laboratories,
NEC Corporation,
4-1-1,Miyazaki,Miyamae-
8:30
ku, Kawasaki213,Japan)
P2. Classificationof fluent speechin coarseacousticclasses.PaulEric Stern (IntelligentSystemLaboratory,Xerox PoloAlto Research
Center,3333 CoyoteHill Road, Palo Alto, CA 94304)
This work is motivatedby resultsof recentstudieswhichshowthat
lexicalaccess
usingrobustbroadphoneme
classes
canpotentially
resultin
smallsetsof candidateworkdsfrom a largelexicon,and thusis effective
Broadphoneticclasseshavebeendemonstratedto be usefulfor con-
forlargevocabulary
wordrecognition.
In thispaper,a setof broadpho-
straining
search
duringlexicalaccess
butnecessitate
thattherecognition
ofbroadphonetic
features
beachieved
inanerror-free
mode.Thisgoalis
nemeclassessuitablefor Japaneseand a new multilevellexicalaccess
modelare proposed.First, broadphonemeclasses
that haverobustfea-
notrealisticduetotheabstract
definition
of phonetic
classes.
However,a
similartaskmaybeperformed
throughtherecognition
ofacoustic
classes
that are subsequently
mappedto phoneticcategories.
A coarseacoustic
recognizcr
hasbeenimplemented
in thecontextof a multispeaker
fluent
speech
recognition
system.
It furnishes
robustacoustic
representations
corresponding
to differentdegrees
of granularity
of speech
thatwill constrainfurtherprocessing
onthesignal.
Thisclassifier
hasbeenimplementedusinga Bayesian
technique
allowingtheapplication
ofdifferentkinds
of classrecognition
decisions.
The parameters
usedto represent
the
speech
signalaredependent
ontheacoustic
classes
andrangefromwhole
spectrum
characteristics
to specific
discriminating
features.
Thechoiceof
acoustic
classes
isdiscussed,
onemaincriterionbeingthemaintenance
of
turesforJapanese
areinvestigated,
andtheirconstraining
powerisexaminedusinga dictionarycontaining
over20 000 words.Next,a multilevel
lexicalaccess
modelisproposed
basedonourstudyaboutthebroadphonemeclass.The modelconsists
of fourstages:
syllablenucleus
detection,
consonantclassification,syllable nucleus classification,and detailed
phoneme
classification.
Thelexicalsearchspacecanbesignificantly
reducedusingtheaccess
model.Finally,a wordclassification
methodbased
ontheaccess
modelisalsoproposed.
Results
ofrecognition
experiments
wereencouraging.[This studywasconductedwhile the authorwasvisit-
ingat the Research
Laboratory
of Electronics,
MIT, Cambridge,
MA
02139.]
a correspondence
betweenacousticand phoneticlabels.Becauseof the
variability
of thesignal,butalsoof thepropensity
to errorof anyrccognizer,multipleandcontextual
mapping
isadvocated.
Results
arereported
and commentedupon. [Work supportedin part by INRIA
and
DARPA. ]
P$. Appllcationof hiddenMarkovmodelsto automaticspeech
endpoint
detection.J. G. Wilponand L. R. Rabiner(AT&T Bell Laboratories,
Office2C-573,Murray Hill, NJ 07974)
8:45
P3. Using featuresto empirically generatepronunciationnetworks.
AlexanderI. Rudnieky(Departmentof ComputerScience,CarnegieMellon University,Pittsburgh,PA 15213)
Theconstruction
ofhigh-quality
lexicalmodels
forspeech
recognition
systems
isa labor-intensive
process,
requiring
notonlya greatdealoftime
but alsoappreciableexpertiseon the part of the humanmodelbuilder.
$35
9:15
J.Acoust.
$oc.Am.Suppl.
1,Vol.82,Fall1987
Accuratedetection
of theboundaries
of a speech
utterance
duringa
recordinginterval has beenshownto be crucial for reliableand robust
automariespeechrecognition.The endpointdetectionproblemis fairly
straightforwardfor high-levelspeechsignalsspokenin low-level station-
ary noiseenvironments.
However,theseidealconditions
do not always
exist.Oneexample,wherereliableworddetectionis difficult,is speech
spokenin a mobileenvironment.
Currently,mostendpointdetectionalgorithms
useonlysignalenergyanddurationinformation
to performthe
endpoint
detection
task.In thispaper,anendpoint
detection
algorithmis
114thMeeting:
Acoustical
Society
ofAmerica
S35
detection schemeswere tested. The results showed that the HMM-based
caltract.Thispropertyis in conflictwithlinearsource-filter
models
of
speech
production
andan effortis madeto minimizetheeffectof the
fundamental
frequency
F0 ontheanalysis
result[e.g.,Hermansky
etal.,
Proceedings
IC.dSSP-83(IEEE, New York, 1983),pp. 778-780]. Our
experiments
showthatthehumanauditory
perception
hasproperties
sim-
approach
to endpoint
detection
performed
significantly
betterthenthe
energy-based
system.
Theoverallaccuracy
ofthesystem
usingtheHMM
endpointdetector,whentestedon the 11 worddigitsvocabulary(zero
throughnineandoh) with speech
recorded
in variousmobileenviron-
ilar to the abovedescribed
propertiesof automaticanalyses.
The method
of confusion
scalingis appliedin pairedcomparison
of syntheticvowellike stimuliwith varyingF0 andthesecondformantfrequency
F2. The
resultsshow that the perceptualestimateof formant positiongoes
ments,was99.4%. A toprecognition
performance
of 99.7%,onthesame
conditions,wasachievedby usingan HMM recognizerwith explicitendpointing.
througha cycleof positive
andnegative
deviations
astherelativeF2/FO
frequencygoesfrom one integralnumberto the next. The positionis
estimatedthe mostaccuratelywhenthe formantpeakfallseitherinto a
harmonicpeakor if it liesrightbetweentwoharmonicpeaks.The maxi-
presented
thatisbasedon hiddenMarkovmodel(HMM) technology.
Basedon a speaker-dependent
speechdatabase
from four talkers,and
recordedin a mobileenvironmentunderfivedifferentdrivingconditions
(includingwhiletravelingat 60 mphwiththefanon), severalendpoint
mal deviation of the estimate due to harmonics of the F0 from the 120-Hz
9:30
P6. Sometechniquesfor erestingrobuststochasticmodelsfor speech
recognition.
Chin-Hui Lee (SpeechResearchDepartment,AT&T Bell
Laboratories,600 MountainAvenue,Murray Hill, NS 07974)
Recently,hiddenMarkovmodels(HMM) havebeenappliedsuccessfullyto bothisolatedandconnected
wordrecognition.
However,whenthe
sameformulationis adoptedfor recognitionof moreconfusable
vocabu-
lariessuchasEnglishalphabets,
therecognition
performance
isoftenless
satisfactory.
The mainreasonis that a moreaccuratemodelis required.
Sucha modelshouldbemorerobustagainstsmalltrainingsamplesizes
andshouldalsobeproperlyinitializedsothat thefinerfeaturesusedto
discriminate
confusable
wordpairscanbeextracted.In thispaper,three
specific
robustness
issues
willbeinvestigated:
choiceofobservation
densities,modelinitialization,andincorporation
of durationinformation.In a
step-by-step
attemptto address
thoseissues,
it wasfoundthat the same
HMM formulationcan still be adoptedif acoustic/phonetic
knowledge
aboutthevocabularyistakenintoaccountin themodelparameterestimationandrecognition
phases.
Testingona 39-wordEnglishalpha-digitvocabulary,in a speaker
trainedmode,indicates
thattherecognition
performancecanbesignificantly
improvedandtheresultsarecomparable
to the
template-based
DTW recognizer
if modelparameters
are properlyinitializedand durationalinformationis adquatelyincorporated.
9:45
neighborhood
in the2-kHzsecond
formantregionisaboutq-0.5%. Our
findingsimplythat whenmodelingthespeech
perception,
asin theautomaticspeechrecognition,
a certaindegreeof sensitivityof the analysis
technique
to F0 mightbebeneficial.
10:15
P9. The importance
of contexton therealizationof phoneroes.
Francine
R. Chen (Xerox PARC, 3333CoyoteHill Road,Palo Alto, CA 94303)
Linguists
andspeaeh
researchers
haveformulated
manyrulesdescribing the variabilityin the phoneticrealizationof spokenwords.Usinga
databaseofspoken
sentences
thathasbeenphonetically
transcribed
(Lareelet al., "Speechdatabase
development:
Designand analysisof the
acoustic-phonetic
corpus,"DARPA SpeechRecognitionWorkshop,
1986),someoftheserulesarequantified
byexamining,
theeffectof differentphonereitenvironments
on thephoneticrealizationof spokenwords
relativeto a canonicaldictionaryrepresentation.
Modificationsare analyzedin termsofthegeneralcategories
ofinsertion,
deletion,substitution,
or match,andin detailin termsof eachtypeof modification.
The different
contextsare studiedalongmanydimensions,
includingstress,foot position,partof syllable,andword-initial/word-final
position.Representationsfor compactly
describing
theenvironmental
contextsarealsodeveloped.Preliminaryresultssuggest
that the importance
of eachof the
dimensions
that canbe usedto specifya phoneme's
contextis phonemedependent.Additionally,the strengthof the relationshipbetweenobservedmodifications
andcontextsvaryacrossdimensions
for eachphoneme.[Work supported
in partby DARPA.]
P7. Probabilisticestimationof lexical stress.GhassanJ. Freij (Speech
Laboratory, Cambridge University Engineering Department,
Trumpington
Street,Cambridge
CB2 1PZ,UnitedKingdom)
10:30
A probabilistic
technique
isdescribed
for theautomaticestimation
of
lexicalstresspatternof isolatedwordsusinghiddenMarkov models
(HMMs) with continuousasymmetricprobabilitydensityfunctions.
Stress
information
ispotentially
usefulforlarge-vocabulary
speech
recognition in that it facilitatesthe extractionof more robustphoneticdata
withinstressed
syllablesandleadsto moreefficientlexicalaccess.
Adoptinga binarystressed-unstressed
strategy,
a constrained
HMM network
wastrainedusingobservation
vectors
consisting
oftenacoustic
measurementsofintensity,
pitch,andspectral
balance.
Thesemeasurements
were
extractedfrom a corpusof disyllabicstress-minimal
word pairs,each
wordembedded
in a phraseandrepeatedeighttimes.Further,theunderlyingtemporalstructureofthedataisrepresented
implicitlybytheprobabilityofremaining
in a statein relationtotheprobability
ofexitingfromit.
PI0. An integratedapproachto automaticdetectionof retroflexedand
high-frontedapproximantsin continuousspeech.Roy Gcngcl and
JamesHieronymus(Institute for ComputerSciences
and Technology,
Bldg. 225, A216, National Bureauof Standards,Gaithersburg,MD
Using this technique, correctnessof classificationwas measuredto be
ence."For example,a basicframe of referenceis the energyin the frequen-
89% for stressed
syllablesand 81% for unstressed
syllables.
cy bandbetweenapproximately
2-3 kHz. Accordingto formanttheory,
theenergylevelin thisbandshouldbe relativelylow for retroflexed
approximants(F I-F3 below2 kHz) andrelativelyhighfor high-fronted
approximants
(F2,F3 above2 kHz for) malespeakers.
In contrast,the
energybandbetweenabout1.2-2 kHz shouldberelativelyhighfor retroflexedapproximants
whilethebandbetween
about0.6-1.6 kHz shouldbe
10:00
Pg. Should ASR front-end be insensitiveto fundamental frequency?
(perceptualshift of formantpositiondue to fine harmonicstructureof
voicedspeech).Hynek Hermansky(SpeechTechnologyLaboratory,
3888 State Street, Santa Barbara, CA 03105)
Due to the fineharmonicstructureof the sourcespectrumof voiced
speech,
mostautomatic
speech
analysis
techniques
estimate
formantpositionsthat systematically
deviatefrom the resonantfrequencies
of the vo-
S36
J.Acoust.
Soc.Am.Suppl.
1,Vol.82,Fall1987
20899)
Our goalis the development
of speaker-independent,
semivowel
detectorclassifiers
for usewith continuous
speech[ R. W. GengelandJ. L.
Hicronymus,
J. Acoust.Soc.Am. Suppl.1 80, S19(1986)]. Progress
on
detectionof retroflexedapproximants
(/r/,/x/,/*ff) in onebranchof a
classification
tree, and high-frontedapproximants(/y/,/i/) and highfrontvowels(/I/,/el/,/•/)
in another,isreported.The analyticalscheme
reliesheavilyon energyratiosselectedon the basisof "framesof refer-
low for high-frontedapproximants.By using"energy2000-3000" aspart
of thedenominator
for a retroflexiondetectorandasa partof thenumera-
tor for a high-frontingdetector,energyratiosare developed.
The quotients of theseratios are then usedin two-dimensionalcluster analyses.
Otherratiosareusedin subsequent
clusteranalyses.
Resultssofar indicatethatgreaterthan90% of targettokenscanbecorrectlydetected
in a
corpusof severalhundredreadsentences.
Ratiosof correctdetections/
114th
Meeting:
Acoustical
Society
ofAmerica
S36
incorrectdetectionsvary betweenapproximatelyi.0/0.63-1.0/2.50.
Someprosandconsof themethodwill bepresented.
[Work supported
in
part by DARPA ContractN0003984PD41304.]
11:15
PI3. Speaker-independent
automatic
vowelrecognition
based
onoverall
spectralshapeversusformants.StephenA. Zahorianand Amir
J. Jagharghi
(Department
of Electrical
andComputer
Engineering,
Old
DominionUniversity,Norfolk, VA 23529)
10:45
PII. Across-speaker
and within-speakervariability of British English
sibilant spectralcharacteristics.P. F.D. Seitz, R. A.W. Bladon, and L
M. C. Watson (Phonetics Laboratory, University of Oxford, 41
WellingtonSquare,OxfordOXI 2JF, England)
Testinghypotheses
regardingthe potentialasphonemediscriminators
of certainpropertiesof"physical" and "auditorilytransformed"sibilant
spectra[A. Bladonand F. Seitz,J. Acoust.Soc.Am. Suppl.I 80, S19
(1986)], thepresentstudydrawsona database
of 20 maleand20 female
talkers,containing
over2000tokensof/s/,/j'/,/z/,
and/3/in a variety
of phoneticcontextsandspeakingstyles.Two automaticparameterextraction routines were used to obtain measurements,for each token, of
physicalandauditorilyscaledvaluesof themainspectralpeak,gradients
of the leadingand trailing spectraledges,and bandwidthof the peak.
Especially
in females'productions
of thespicsis,largeandcharacteristic
variationsin theseparameterswereobservedas correlatesof individual
talker,phoneticcontext,andstyle.Overviewsof theenvelopes
of physical
and auditoryvariationare given;baseduponthis knowledge,a speakeradaptivestrategyfor discrimination
of BritishEnglishsibilantsis proposed.[Work supported
by theAlveyProgramme.]
Automaticrecognition
experiments
wereperformed
tocompare
overall spectral
shapeversusformants
asspeaker-independent
acoustic
parametersfor vowelidentity.Stimuliconsisted
of four repetitionsof 11
vowels spoken by 17 female speakersand 12 male speakers
(29, I 1,4 = ! 276totalstimuli). Formantswerecompul•.dautomatically
bypeakpickingof 12th-order
LP modelspectra.
Spectral
shapewasrep-
resented
usingthreemethods:
( 1) bya cosine
basisvectorexpansion
of
thepower
spectrum:
(2) astheoutputofa 16-channel,
l/3-octfilterbank;
and(3) astheoutputofa 16-channel
reel-spaced
filterbank.Automatic
•cognitionwasbased
onmaximum
likelihood
estimation
in a multidimensional
space.For all casesconsidered,
therepresentations
basedon
spectal
shape
resulted
in significantly
higherrecognition
accuracy
than
for recognition
basedon onlythreeformants.
For example,
usingthe
entiredatabase
of all speakers
and 11vowels,recognition
basedon spectral shapewasabout85% vs69% for threeformants.
If thedatawere
restricted
tofemale
speakers
andtheseven
vowels/a,i,u,•,a.,1,•/,
recognition wasabout97% basedon spectralshapeversus84% for formants.
Theseresultsindicatethat, at leastfor automaticrecognitionof vowels,
spectral
peakdetection
is neithernecessary
norsufficient.
[Worksupportedby NSF.]
11:00
P12. Automariedetectionfor diphthongs.Hisao M. Chang (NYNEX
Corporation,70 WestRedOak Lane,WhitePlains,NY 10604)
It is generallyrecognizedthat diphthongsdo not have steadystates
andonly displayidentitiesthrougha dynamicshiftof their spectra.In
Miller's auditory-perceptual
theory,dynamicshiftsof diphthongspectra
arerepresented
aspathson a "vowelmap" [1. D. Miller, J. Acoust.Soc.
Am. Suppl.1 81, S16 (1987)]. From theutterances
of Englishdigitsby
two maleand two femalenativespeakers,an auditory-perceptual
transformationsystemand a segmentation
rule wereusedto transformthe
spectralprominences
contoursderivedfromthoseutterances
containing
diphthongs/al/and/el/inpathsonthevowelmap,andit wasfoundthat
all pathsfrom thesamediphthong,independent
on talker'ssexand phoneticcontexts,travelin the samerouteand form a "diphthonggig." After
the detailedanalysisof the paths,an automaticdetectionalgorithmwas
developed
basedon angles,durations,lengths,origins,and otherattributesof thepaths.Whenapplyingthealgorithmto digitutterances
from
21 newtalkers,therecognition
accuracies
for/al/and/eI/were 75% and
90% while the insertionrates were only 1.1% and 4.5%, respectively.
[Work supported
byNINCDS anddoneat CentralInstitutefortheDeaf,
St. Louis MO.]
S37
d. Acoust.Soc.Am.Suppl.1, Vol.82, Fall 1987
11:30
P14. Formant tracking using statistical linttern recognition.Robert
T. GayvertandJamesHillenbrand(RochesterInstituteof Technology
ResearchCorporationand RochesterInstitute of Technology,75
HighpowerRoad,Rochester,NY 14623)
Formanttrackersthatusepeak-picking
algorithms
andad hoerules
tend to sufferfrom occasionalseveremistakesin labelingformants.Re-
cently,Kopec[IEEE Trans.Acoust.Speech
SignalProcess.
ASSP-34,
709-729 (1986)] useda statisticalapproachbasedon hiddenMarkov
modelsto avoidthesekindsof problems.
Thisstudyusesanotherstatisticaltechnique
basedondiscriminant
analysis.
A modelistrainedonhandmarkedformanttrajectories
and variousfeaturesfrom a collectionof
utterances. The same features are then extracted from a test utterance and
usedto determinethemostprobableformantfrequencies.
Any combinationof features,includingpeaksfrom LPC andDFT spectra,canbeused
withthistechnique.
Preliminaryresultsindicatethat thismethodavoids
seriousmistakes.Resultsof evaluatingthe formanttrackeron a large
numberof trainingandtestsetswill be presented.[Work supported
by
RomeAir Development
CenterundercontractF3060285-C-0008.
]
114thMeeting:Acoustical
Societyof America
S37
WEDNESDAY MORNING, 18 NOVEMBER 1987
BOUGAINVILLEA
ROOM, 8:30TO 11:35A.M.
SessionQ. EngineeringAcousticsII: SpecialSessionon DirectionalMicrophoneSystemsfor Airborne
Sound
JamesE. West, Chairman
AT&T Bell Laboratories,600 Mountain Avenue,Murray Hill, New Jersey07974-2070
Chairman's Introduction---8:30
Invited Papers
8:35
QI. A unitarymultielement
ultrasonic
arrayforfocused
imaging
in air. LeslieKay (220Boylston
Street,Unit
9007, Boston,MA 02116)
A condenser
microphone
isdescribed
thatincorporates
20 independent
conductive
elements
coupledto a
single
laminardiaphragm.
Theelements
areseparately
excited
byanelectrical
signal,
delayed
intimerelative
to
adjacent
elements,
to enabletheformationof a focused
beamwithintheclosenearfield
of thearray.Usinga
radiationfrequency
coveting
anoctavebandwidth
from100-200kHz, a spatialresolution
of0.2in. parallelto
theapertureand0.1 in. perpendicular
to theapperture
at thepointof maximumfocushasbeenachieved.
No
apertureshadinghasbeenincorporated
at thisstagesothat thediffractionfieldcanbeexplored.Sincethisis
formedbya verywidebandwidthradiation,anunusualfieldplotwasexpected.
The resultsarediscussed
anda
videoshowsexamplesof the highresolutionrealtime imagingin air that cannowbeachieved.This hasmany
applications,
particularly
in automation
asanalternative
toopticalvisionwhendistance
toanobjectisessential
information.
9:00
Q2. A review of adaptive microphonearrays. M. M. Sondhi (Room 2D-536, AT&T Bell Laboratories,
Murray Hill, NJ 07974)
In this talk, severalalgorithmsfor adaptiveoptimizationof broadbandmicrophonearrayswill be described.The arraysmay be linear,two-dimensional,
or three-dimensional.
Eachmicrophonein the array feeds
a tappeddelayline filter,and theoutputsof the filtersaresummedto givethe finaloutput.The problemto be
discussed
is that of adaptivelyadjustingthe tap weightsof the filtersin order to optimallyreceivea desired
speech
signalin thepresence
of broadband
noisesources
withunknownlocations
andpossibly
slowlyvarying
characteristics.
9:25
Q3. Directionalprocessing
for interferencereductionin hearingaids.W. M. Rabinowitzand P.M. Peterson
(ResearchLaboratoryof Electronics,MIT, Room 36-761,Cambridge,MA 02139)
Listenerswith hearingimpairmentsoftenhavegreatdifficultyin interpretingacousticenvironments
having multiple sourcesand/or reverberation.Directional processing,obtainedby weightingthe outputsof multiple sensors,offerspotentialfor reducingsuchinterference,althoughcosmeticconsiderations
imposefundamentallimitationson performance.Infixed processing,
weightsare held constantto achievea fixedantenna
pattern(pointingstraightahead)andarechosenasa compromise
betweenclassical
andsupergain
limitssoas
to maximizedirectivitywith tolerablesensitivityto receivernoise.A particularsecond-order
gradientmicrophonesystem,with a sensorspanof 4.1 cm and formedsimplyby subtractingthe outputsof two cardioid
capsulehearing-aidmicrophones,
exhibitsa directivityof 8.5 dB, whichis nearoptimum(9.0 dB) for its noise
sensitivity.In adaptiveprocessing,
weightsare continuallyadjustedaccordingto propertiesof the environment. An adaptivealgorithm usingtwo omnidirectionalmicrophonesseparatedby 20 cm ( • headwidth) has
beenevaluatedwith a targettalkerstraightaheadandan interference
sourceat 45øin threecomputer-simulated
environmentswith zero, moderate,and severereverberation.Both analyticmeasuresand intelligibilitytests
indicatesubstantialreductionsin interferencein zeroand moderatereverberationand no reduction,or degradation,in severereverberation.
Additionaland morerealisticevaluations
of thesefixedand adaptivesystems
arerequiredto determinetheirsuitabilityfor practicalhearingaids.[Work supported
by NIH. ]
9:50
Q4. Automatic speech-seeking
microphonearrays for teleconferencing.G. W. Elko (Room 2C-574, AT&T
Bell Laboratories,Murray Hill, NJ 07974)
The effectsof reverberationon speechtransductionin largeroomscanseverelylimit the intelligibilityof the
desiredspeedsignal.In isotropicacousticfields,asidefrom locatingthe microphonein closeproximityto the
S38
J.Acoust.
Soc.Am.Suppl.1,Vol.82,Fall1987
114thMeeting:
Acoustical
Society
ofAmerica
$38
speech
source,it is necessary
to develophighlydirectionalmicrophone
systems.
Concomitant
with microphonearraydesigns
for teleconferencing
is theneedto steerthearrayat thedesiredspeech
sourcein orderto
maximizethe direct-to-reverberant
signalenergy.The problemthat will be discussed
is that of designing
broadband
(speech
bandwidth)microphone
arraysthatarecapable
ofdetecting
a speech
source
andautomaticallysteeringthe array to the directionof the source.
Cont•butedPapers
10:55
10:15
Q5. Three-dimensional
microphone
arrays.J. L. Flanagan( Information
PrinciplesResearchLaboratory,AT&T Bell Laboratories,Murray Hill,
Q7. Characterization of the envelopeprotecting an acousticdetection
system. D. Vaucher De La Croix, M. Lathuili•re, and L. P6rier
NJ 07974-2070)
( MetravibR.D.S., 64 ChemindesMouilles,69130Ecully,France)
Low-cost, high-qualitymicrophonesand integratedelectronics
promptexaminationof sophisticated
arraysfor soundpick-upin large
enclosures.
A three-dimensional,
uniform configurationof receiversis
studiedandshownto haveseveralbenefits.Beamforming
anddelaysteeringcanbeaccomplished
overthe4•rsolidanglewithoutspatialambiguity. Beamwidthisessentially
independent
of steeringdirection.As in ar-
In a previouspaper,a schemefor computingthe radiationperturbation dueto a two-dimensional
envelopeof arbitraryshapeenclosing
an
raysof fewerdimensions,
usablebandwidth
is governed
at the upper
frequency
limit by receiverspacing
andat thelowerfrequency
limit by
lineardimensions.
Harmonicnestingin threedimensions
canextendthe
bandwidth
of uniquespatialdiscrimination
to anydesiredrange.Range
selectivity,
additionalto uniquedirectionaldiscrimination,
canbe realizedby delaysteeringto nonplanarwavefronts.
acousticalsourcewaspresented[D. Fiehot and J. M. Parot, D.3-5, 12th
ICA, Toronto (1986) ]. The formulation associatesstructural finite ele-
mentsand acousticintegralequations.
Thoughoriginallyaimedto solve
fluid-structureinteractionproblemswith strongcouplingbetweentransducerand envelopefor ka valuesup to 30 (k = acousticwavenumber,
a = half-largestdimensionof the envelope),the codenamedABER2D
wasappliedtodetermine
theinfluence
oftheenvelope
shapeand/ormaterial on the directivityof the enclosedtransducerwith air asambientfluid.
Deviationsfrom thefreefieldreference
configuration
havebeencomputedat low ka values(typicallyka _• 1), startingfrom a thin circularenvelope and progressively
flatteningit to ellipticalshape.Suchcalculations
haveorientedchoicesconcerninggeometryand certainmaterialcharacteristicsand resultedin designinga flattenedpolypropylene
protection
envelopeadaptedto an acousticdetectionsystem,whichdisplaysgood
transparencyin the frequencyband of interest.[Work supportedby
SEFT. ]
11:15
10:35
QS. Unidirectional,second-order•radient microphone.J. E. West, G.
Q6. The evaluationof sourcestrengthusinga microphonearray over a
M. Sessler,
• andR. A. Kubli (AT&T Bell Laboratories,
Murray Hill,
hard reflectingsurface.Stewart A. L. Glegg and Richard C. Smart
(Department of Ocean Engineering,Florida Atlantic University, Boca
NJ 07974)
Raton, FL 33431 )
This studyhasbeenundertakento measurethe noisesourceheighton
highwayvehicles.A verticalseven-element
microphonearray is usedand
the methodof analysisis basedon the sourcebreakdowntechniquedevel-
opedby FisherandTester.Thisiscapableof givingnarrowbandor «-oct
sourcespectrafor eachindividualsourcein a distribution,with resolution
down to zero frequency,providingthe approximatesourcepositionsare
known, and there is a high signal-to-noise
ratio. This methodhas been
evaluated both in an anechoic chamber and in an outdoor environment
over a hard surface. Good results have been obtained for sources which
are0.13m apartdownto 125Hz. However,if thesourcepositions
arenot
exactly specified,the lower limiting frequencyis increasedto 500 Hz.
[ Work is sponsored
by theFloridaDepartmentof Transportation.
]
S39
J. Acoust. Sec. Am. Suppl. 1, Vol. 82, Fall 1987
A second-order
gradientmicrophone
withunidirectional
characteristicsis described.The microphoneconsistsof two commerciallyavailable,
first-ordergradientelectret microphonesthat are properly baffledand
arrangedwith their rotationalaxesin line. The outputof one of these
transducers
issubtracted
fromthedelayedoutputof theothertransducer.
The unidirectionalmicrophoneshowsa directionalcharacteristicthat is
relativelyfrequencyindependent,hasa 3-dB beamwidthof the mainlobe
of _+40 degrees,and exhibitssidelobes10-20 dB below the mainlobe.
After equalization,thefrequencyresponse
of themicrophone
in itsdirection of maximumsensitivityis within :k 3 dB between0.3 and4 kHz. The
sensitivity
of themicrophone,
includingitsequalization,
is - 60 dBV/Pa
at 1 kHz and the equivalentnoiselevel for the abovefrequencyrange
amountsto 28 dB linear or 20 dB(A). • Permanentaddress:Technical
Universityof Darmstadt,6100 Darmstadt,WestGermany.
114th Meeting: AcousticalSociety of America
S39
WEDNESDAY
MORNING,
18 NOVEMBER
1987
UNIVERSITY
LECTURE HALL, 8:30 TO 11:30 A.M.
SessionR. Psychologicaland PhysiologicalAcousticsIII: Temporal Perceptionand Comodulation
Robert H. Gilkcy, Chairman
ResearchDepartment,CentralInstitutefor theDeaf, 818 S. Euclid, Saint Louis,Missouri63110
ContributedPapers
8:30
9:00
R1. Discriminationof time-expandedtonal sequences.R. D. Sorkin and
R3. Temporalaspectsof the auditory system:Gap detectionand the
M.P. Snow(Departmentof Psychological
Sciences,
PurdueUniversity,
West Lafayette,IN 47906)
modulation
transfer
function.
T.
G. Forest
and
David
M.
Green
(Psyehoacoustics
Laboratory,Departmentof Psychology,
Universityof
Florida, Gainesville, FL 32611 )
Subjects
werepresented
with two sequences
of tones,eachconsisting
of eight50-mssinusoidal
tones.Subjects
had to discriminatewhetherthe
sequences
werethesameor differentbasedsolelyon the frequencypattern
definedby eachsequence
of tones.The correlationbetweenthe temporal
envelopes
ofthetwosequences,
thevariabilityofsequence
timing,andthe
lengthof the intersequence
intervalweremanipulated.In the "correlated"condition,thegapsbetweenthetonesin thesequences
wererandomly
variedacrosstrials(sequences
withina trial hadidenticaltemporalenvelopes);in the"uncorrelated"
condition,theenvelopes
variedbothacross
and within trials.The resultsreplicatedan earlierexperiment[R. D.
Sorkin,J. Acoust.Soc.Am. (in press)]. Performance
in the correlated
conditionwasindependent
of temporalvariabilitybut decreased
with increasesin temporalvariability.This patternof resultsis consistent
with
theassumed
dominance
of "trace"and"context"modeprocessing
in the
twoconditions.
In anadditionalmanipulation,
all toneandgapdurations
in thesecondsequence
of eachtrial wereexpandedby 40%. Performance
in the time-expanded
conditionresembledthat foundin the correlated
condition.This resultis interpretedas evidencefor a durationscaling
process
in auditorymemory.[Work supportedby AFOSR. ]
A three-stage
modelconsisting
of a bandpass
filterfollowedby a nonlinearelementanda low-pass
filteris oftenusedto modeltemporalprocessing
in theauditorysystem[e.g.,N. F. Viemeister,J. Acoust.Soc.Am.
66, 1364-1380 (1979)]. Two experimentalparadigms,the detectionof
gapsin noiseand of sinusoidalmodulationof noise,have beenusedto
estimatethe parametersof this model. A simulationof this model was
usedto "listen" to waveformsin gapdetectionand modulationdetection
experiments.
Responses
of thesimulatorwerebasedonstatisticalcalcula-
tionsat theoutputof thelow-pass
filterstageof themodel.Our decision
statistic was the maximum-to-minimum
ratio of the waveform from the
low-passfilter.Goodagreement
betweenthe dataproducedby normalhearinghumanobservers
andthe simulatoroccurredwhenthe bandwidth
oftheinitialfilterwas4000Hz andthetimeconstant
ofthelow-pass
stage
was3 ms. [ Researchsupportedby NSF. ]
9:15
R4. Illusory continuity of periodic sounds:A eomparisanof tonal and
infratonal
temporal
induction. Richard
M. Warren,
John
M. Wrightson, and Julian Puretz (Department of Psychology,
University of Wisconsin--Milwaukee, P.O. Box 413, Milwaukee, WI
53201 )
8:45
R2. Proportional target-tone duration as a factor in the diseriminability
oftonalpatterns.CharlesS. WatsonandGary R. Kidd (Departmentof
Speechand Hearing Sciences,Indiana University, Bloomington,IN
47405 )
A seriesof experimentson listeners'abilitiesto extractinformation
frompatternswithvaryingtotaldrrationsandnumbersof tonalcomponentshaspreviouslybeenreported[J. Acoust.Soc.Am. Suppl.173, S44
(1983); 77, SI (1985)]. In thoseexperimentslistenerswere testedin
high-stimulus-uncertainty,
same-differentpattern discriminationtasks,
in whichthe tonalpatternsto bediscriminated
differedby changesin the
frequencyof one or more components.
Discriminationperformancein
Tonesmay appearto remain on continuouslywhen alternatedwith
soundshavingappropriatespectralcompositionand intensity.The limiting conditionsfor this illusory continuity have been usedto definethe
characteristics
of neuralspectral(place) analysisof tones.The present
studyextendsinvestigation
oftheapparentcontinuityofinterruptedcomplexperiodicsoundsto infratonalfrequencies,
exploringthe rangeof repetitionfrequenciesfrom 10-2000 Hz. Evidenceis presentedindicating
thatreconstruction
of obliteratedsegments
of periodicsoundsneednotbe
baseduponthe neuralplacemechanisms
associated
with perceptionof
tones.It appearsthat illusorycontinuityof periodicitycaninvolvea perceptualsynthesis
baseduponneuraltemporalinformation,and that ex-
planations
forthelimitsofillusorycontinuityoftones("pulsationthresholds") solelyin termsof a frequencydomainanalysisinvolvingneural
placeinformationmay be incomplete.[Work supportedby AFOSR. ]
thosetaskswasconsistentwith previousmeasuresof the frequencyresolv-
ing powerof the auditorysystemwhenthepatternscontainedoneto three
equal-durationcomponents,for total pattern durationsfrom 62.5-2000
ms. As the numberof componentswasraised,discriminationthresholds
increasedby largeamounts,often by factorsof 10-100 for patternswith
more than seven-eightcomponents.While this result might imply an
informationallimit on pattern processing,it is also consistentwith the
hypothesisthat targettonesare equallywell resolvedif theyoccupyequal
proportionaldurationsof the patternsin which they occur. Resultsof a
newexperiment,in whichproportionaldurationsof targettonesand the
numberof tonesperpatternwereindependently
varied,suggest
thatproportionaldurationof the targettonesis in factthe primarydeterminantof
patterndiscriminabilityfor tonalpatternsrangingfrom 100-1500ms in
total duration.[Work supportedby AFOSR andNIH/NINCDS. ]
S40
J. Acoust.Soc.Am. Suppl.1, Vol. 82, Fall 1987
9:30
RS. Critical
bandwidth
for modulation
detection.
William
A.
Yost
(Parrely Hearing Institute, Loyola University, 6525 N. Sheridan,
Chicago, IL 60201)
Two sinusoidalcarriersseparatedby frequencyF were eachsinusoidally amplitudemodulated(AM). Subjectswereaskedto discriminate
betweena complexin whichthe two AM signalshadthe samephaseanda
complexin which the phasespectraof the lower frequencyAM componentsweredelayedrelativeto the upperfrequencyAM components.
The
114thMeeting:AcousticalSocietyof America
S40
thresholdvalueof thephaseshiftwasmeasured
fromthree-pointpsycho-
10:15
metric functions obtained from a two-alternative, forced-choicetask. A
broadband-noise
backgroundand randomvariationin overalllevelwere
usedto forcethe two normal-hearing
listenersto attendto the temporal
structureof the two-toneAM complexes.
The frequencyseparationbe-
R8. The effectof signal-frequencyuncertaintyin a CMR paradigm.John
H. GroseandJosephW. Hall, III (DivisionOtolaryngology
Head and
NeckSurgery,Schoolof Medicine,Universityof NorthCarolina,Chapel
tweenthe two carriers (F), the ratesof AM modulation,and the form of
Hill, NC 27514)
the phaseshift (entirewaveformor envelopedelay) wereparametersin
the study.The resultsindicatethat the thresholdfor detectingthe phase
The phenomenon
of comodulationmaskingrelease(CMR) indicates
that the auditorysystemis capableof comparingthe outputsof several
auditorychannels
simultaneously.
Thepresence
of thesignalispresumed
to be cuedby a dissimilarityin the temporalpattern in that channel,
relativeto the remainingcomodulatingchannels,due to the additionof
the signal.In its simplestform, sucha cuingmechanismcouldoperate
quiteindependently
of anyapriori knowledgeof whichchannelthe signal
occursin. To testthispossibility,a studywasundertakento comparethe
effectof signal-frequency
uncertaintyin a comodulatedanda noncomodulatedbackground.It washypothesized
that the detectionof a signal
whosefrequencyfluctuatedrandomly from trial to trial would be less
deleteriouslyaffectedin a comodulatingbackgroundthan in a noncomodulatingbackground.A novel feature of this study was the use of
amplitude-modulated
pure-tonecomponents
asthebackgroundmasker.
Resultsto dateindicatethat the effectof signal-frequency
uncertaintyis
itself small relative to fixed-frequencysignals,and no significantdifferencehasemergedbetweenits measurementin comodulatedversusuncomodulatedbackgrounds.
shift is small when the two carriers are within a critical band. However,
listeners
arestillquitesensitive
to thephaseshiftsfor verylargefrequency
separations
betweenthecarriers.The resultswill bediscussed
in termsof
the auditorysystem's
abilityto usetemporalmodulationto identifycommonsources
in a complexsound.[Work supportedby AFOSR-Life Sciencesand the NINCDS.]
9:45
R6. Discriminationof envelopephasedisparity.GregoryH. Wakefield
and Brent Edwards (Department of Electrical Engineeringand
ComputerScience,
Universityof Michigan,Ann Arbor,M148109-1109)
Thesensitivity
of theauditorysystemto changes
in ongoingtemporal
structuresacrossdifferentspectralregionsis investigated
usingsinusoidally amplitude-modulated(SAM) carriers. Previous resultsare extendedfor thedetectionof phasedisparitybetweentheenvelopes
at two
carriers[J. Aeoust.Soc.Am. Suppl.181, S34 (1987) ] to thediscrimination of suchdisparitywhena nonzerorelativephaseoffsetbetweenthe
envelopes
is present.For a standardSAM two-carriercomplexwith a
relativephaseoffsetof •b,the relativephasedisparityof the comparison
•b+ A4 wasadjustedto measurediscrimination
thresholdasa functionof
•b.The resultsshowthatA•bvariedby morethana factorof 2 as•branges
from0-180 deg.Modulationfrequency
(8-64 Hz) or carrierseparation
(500 Hz, 1-4 kHz) haslittle effecton this phasedependence.
When ex-
pressed
asa change
in envelope
correlation
(p), however,
wefindthatAp
is constantas a functionofp. Additionalexperiments
usingharmonic
complexes
for envelopes
supportthehypothesis
that envelopecorrelation
is the primary determinantof performance.A neural-basedcoincidencedetectormodelof envelopecorrelationis proposedto accountfor these
findings.[Researchsupportedby AFOgR.]
10:00
R7. Evidencefor cross-channelprocessingin detectionof envelopephase
disparity. Elizabeth A. Strickland, Neal F. Viemeister, Deborah
A. Fantini (Department of Psychology,University of Minnesota,
Minneapolis,MN 55455), and Margery A. Garrison (Departmentof
CommunicationDisorders,Universityof Minnesota,Minneapolis,MN
10:30
R9. Comodulationmaskingreleasefor envelopedecorrelationcueversus
envelopelevel differencecue. JosephW. Hall, III and John H. Grose
(Division of OtolaryngologyHead and Neck Surgery, School of
Medicine,Universityof North Carolina,ChapelHill, NC 27514)
In pastinvestigations
of comodulation
maskingrelease(CMR) it was
difficultto identifythe detectioncueusedby the listener,asseveraldifferent cueswereavailable.The presentstudyattemptedto isolatetwo cues:
envelopecorrelationand envelopelevel.The signalwaseither a 10-Hzwidenoisebandcenteredon 500Hz, or a 500-Hz puretone.The maskers
were 10-Hz-wide noise bands centered on 400 and 500 Hz (either co-
modulatedor noncomodulated).
In oneexperimentthesame10-Hz-wide
noisebandcenteredon 500Hz wasusedasboththesignalandthe masker.
Here, the signalresultedin no decorrelationof envelope,but did resultin
anenvelope
leveldifference.
In theexperimentusingthe500-Hzpuretone
as the signal,the signal resultedin a decorrelationcue; however,any
envelopelevelcue wasrendereduselessin this experimentby randomly
rovingthe levelof the flankingbandbetweeneachinterval,andby adjustingthenoiseleveloftheon-signal
bandin thedummyintervalsto thelevel
of the noise-plus-signal
in the signalinterval.The majorresultwasthat
substantial
CMRs occurredboth whenthe envelopelevelcuewasavailable but the decorrelation cue was not, and when the decorrelation cue
wasavailablebut the envelopelevelcuewasnot.
55455)
The sensitivityto thecorrelationbetweentheenvelopes
of twosinusoidally amplitude-modulatedsinusoldswas investigatedin two experiments. Correlation was manipulated by varying the phase disparity
betweenthe envelopes.
In eachexperiment,two carriers(either 1 and 2
kHz or I and 3.2 kHz) weremodulatedat the samefrequency(8 or 128
Hz) and addedtogethereither in phaseor, on signalintervals,with an
adaptivelydeterminedphasedisparity.The startingphaseof theenvelope
of the lowerfrequencycarrierwasrandomizedacrosstrials.In the first
experiment,the lowerfrequencycarrierwaspresented
at 65 dB $PL and
the higherfrequencycarrierwaspresentedat levelsfrom 65 to 25 dB SPL.
No decrementin thresholdwas noted until the higher frequencysignal
was20-40 dB belowthe lowerfrequencysignal.In thesecondexperiment,
the lowerfrequencycarrierwaspresentedat 65 dB SPL to oneear,andthe
higherfrequencycarrierwaspresented
at thesamelevelto the otherear.
Thresholdswereslightlyabovethoseobtainedmonotically.Theseresults
suggestthat subjectsare able to useinformationacrossfrequencychannelsto detectenvelopephasedisparityand do not needto useenvelope
interactionsoccurringwithin a singlechannelin performingthis task.
[Work supported
by NINCD$ GrandsNS12125and NS07889.]
$41
J. Acoust.$oc. Am. Suppl. 1, Vol. 82, Fall 1987
10:45
R10. Comodulation detection differenceswith multiple signal bands.
BeverlyA. Wright andDennis McFadden(DepartmentofPsychology,
Universityof Texas,Austin, TX 78712)
Detectionthresholdswere determinedfor signalsconsistingof one,
two, or fivenoisebandsembeddedin eight "cue" bands.The centerfrequenciesof the signalsrangedfrom 1250-3250Hz in 500-Hz steps,and
thoseof the cuebandsrangedfrom 500-4000 Hz in 500-Hz steps.The
temporalenvelopes
of thecuebandswereeitherall correlatedor all uncorrelated.The envelopes
of the multiplesignalbands( 1) werecorrelated
amongthemselves
as well as with the cue bands,(2) were themselves
correlated,but not with the cuebands,or (3) were themselvesuncorrelat-
ed. As in previous6omodulation
experiments,
thresholds
weresimilarly
poorwhenthe signalandcuebandswereeitherall correlatedor all uncorrelated.Detectabilitywastypically7-10 dB betterwhenthe signalbands
were uncorrclated with the all-correlated cue bands. These results were no
differentfor single-and multibandsignals.Thus the auditorysystemap114th Meeting:AcousticalSocietyof America
$41
pearsbetterableto detectbothsimpleandcomplexsignalsin background
havingthe same--ratherthan different--temporalenvelopes,
aslongas
the temporalstructureof the signal(s)is differentfrom that of the surroundingsounds.[Work supportedby NINCDS Grand NS15895.]
ratherthanbynumber,andviceversa.Implications
for theinterpretation
of certainlanguage-learning
disorders
arediscussed.
[Work supportedby
NIH/NINCDS
and AFOSR. ]
11:15
R12. Informationallimits in speechprocessingby normal and impaired
listeners.Blas Espinoza-Varas,
CharlesS. Watson,and Mary S. Kyle
11:00
(Speechand HearingSciences,
Indiana University,Bloomington,IN
R11. Rate andnumberaslimiting factorsin the perceptionof sequences
of
47405 )
syllables.CharlesS. Watsonand Bias Espinoza-Varas(Speechand
HearingSciences,
IndianaUniversity,Bloomington,IN 47405)
spokenlettersb, c,d, g,p, t, or v, produced
asCVsendingin thevowel/i/.
The durationof eachtokenwaseditedto 75 ms. Syllableonset-to-onset
It hasbeenreportedthat someimpairedlistenerspreceivespeechas
being"jumbled,or asgoingtoo fast,"whichsuggests
that their informationalcapacitymaybe reduced.Recently,work with nonspeech
stimuli
[ WatsonandFoyle,J. Acoust.Soc.Am. 78, 375-380 (1985) ] hasshown
that the amountof spectral-temporalinformationthat can be extracted
from sequentialpatternscan be limited very stronglyby the numberof
freelyvaryingcomponents
includedin a pattern,and only weaklyby the
durationof the individualcomponents.
Usinga variationof the speech
testdescribed
in the previouspaper,informationcapacityof normaland
impairedlisteners
wascompared
forsequences
oftwo,four,orsevensyllables,presented
at ratesof 6.5or 3.9 syllables/s.
Percentinformationtransmission(IT%) was estimatedfor each temporalpositionof the sequences,number of syllables, and syllable rate. The sensorineural
impairedlisteners
hadnearlyuniform45-to-55-dBlosses,
andagessimilar
to thenormallisteners.
Stimuliwerepresented
at approximately
constant
times were 75, 150, and 300 ms. The listener's task was to transcribe the
sensationlevels (30-40 dB) to minimize effectsof differencesin sensitiv-
lettersin eachsequence,
in a testformatin which180sequences
were
ity. The maximumnumberof syllablesyieldingIT% > 50% was,on the
average,6-7 for normallistenersbut 4-5 for the impairedlisteners.
[ Work supportedby NIH/NINCDS and AFOSR. ]
Listeners'abilitiesto process
the detailsof sequences
of soundshave
beenshowntobelimitedbytwomajorfactors:thenumberofcomponents
in the sequence
and the rate at whichthe components
are presented.Indi-
vidualdifferences
in theabilityto process
largenumbers
ofcomponents
at
high presentationrateshavebeenproposedto accountfor certainlanguage-or learning-related
disabilities.
Little attentionhasbeenpaidto the
possibleinteractionsbetweenthesetwo factors,nor to the distributionof
theseabilitiesin the populationof normal-hearinglisteners.A test was
developed
tomeasure
theeffects
of thenumberof syllables
and,independently,thoseof syllablerate,or listener'sabilitiesto process
syllablesequences.The sequences
consistof two, four,or sevennaturaltokensof the
presented,varyingrandomlyin numberandrate.Resultsfor an initial test
groupshowsomeindividual'sperformance
to be morelimitedby rate
WEDNESDAY
MORNING,
18 NOVEMBER
1987
UMS 4 AND 5, 8:30 TO 11:45 A.M.
Session
S. UnderwaterAcoustics
III: Three-Dimensional
Oceanography
andAcoustical
Modeling
Robert P. Porter, Chairman
Department
of ElectricalEngineering,
FT-10, University
of Washington,
Seattle,Washington
98125
Chairman's IntroductionS:30
Invited Papers
8:35
SI. Three-dimensional
oceanographic
acousticmodelingof complexenvironments.
W. A. Kuperman,
MichaelB. Porter,andJohnS. Perkins(NavalResearch
Laboratory,
Washington,
DC 20375)
Remotesensing
combinedwith oceanographic
modelingopensup newpossibilities
for quantiatively
describingverylargeareacomplexoceanographic-acoustic
phenomena.
A complexoceanenvironment
consists
ofvariable
oceanography
including
mesoscale
phenomena
andvariable
topography
suchascontinental
slopes
andseamounts.
Predictingthe acoustical
effectsfrom any to all of thesephenomena
is a computationally
intense
problem
whoseefficient
andaccurate
solutionwill,nodoubt,ultimately
employnewandinnovative
numerical
physics.
Asa stimulus
todeveloping
newapproaches,
three-dimensional
modeling
results
forsuch
complexenvironments
arebeinglookedat usinga technique
thatcanrapidlycalculatepropagation
lossovera
widegeographical
area.Thisapproximate
technique,
whichisbased
onnormalmodetheory,hasbeenapplied
to environments
thatcontainbothvariableoceanography
andtopography.
Of primeinterestin theseinitial
studiesis a searchfor graphicalpatternsthatemergefor complexenvironments
wheretheacoustical
results
reflector "image"theoceanography
andtopography.
It isbelieved
thatthesethree-dimensional
representationsusingcolorgraphics
to displayandconveycomplex
ocean-acoustic
phenomena
will providetheimpetus
to furtherunderstanding
andcomputingtheinteractionof thesephenomena.
$42
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
114thMeeting:Acoustical
Societyof America
S42
9:OO
S2. Dynamicalforecastingof mesoscale
frontsand eddiesfor acousticalapplications.Allan R. Robinson
(HarvardUniversity,
Divisionof AppliedSciences,
Cambridge,
MA 02138)
Real-time
nowcasts
andforecasts
ofoceanic
mesoscale
fields(velocity,pressure,
temperature,
soundspeed,
etc.) arenowfeasible
andhavebeeninitiatedinselected
regions.
Predicting
the"internalweatherofthesea"is
analogous
to meterological
weatherforecasting.
Ourapproach
isbasedonrecentprogress
in phenomenologicalknowledge
andmodeling
capabilities
andissystematic
[A. R. Robinson,
"Predicting
openoceancurrents,
fronts,andeddies,"in Three-Dimensional
OceanModelsofMarineandEstuarineDynamics,
editedby Nihoul
and Jamart(Elsevier,Amsterdam,1987)]; i.e., it combines
dynamicalmodel[A. R. Robinsonand L. J.
Walstad,"The Harvardopenoceanmodel,"J. Appl. Numer.Math 3 (1987) ] andobservational
estimates
via
data assimilation
methods.The predictionproblemwill be overviewed,resultsfrom an ongoingforecast
schemefor theGulf Stream(gulfcasting)will be presented,
the couplingof dynamicalandacousticalmodels
will bediscussed,
andpreliminaryresultsfroma coupledsystemwill bepresented.
9:25
S3. High-resolutionoceanacoustictomogral)hy.Peter F. Worcester,Bruce Cornuelle,Bruce Howe, and
Walter Munk (ScrippsInstitutionof Oceanography,
Universityof Californiaat San Diego, La Jolla, CA
92093 )
The oceanacoustic
tomography
experiments
conducted
to datecanbedividedintomappingexperiments,
in which many sourcesand/or receiversare usedto generatesufficientcrossingray paths to resolvethe
mesoscale
oceanstructure,andcueraging
experiments,
in whichdataareobtainedin a verticalslicebetweena
singlepairof sources
and/orreceivers
in orderto construct
horizontally
averaged
verticalprofiles.
Whileit is
economically
feasibleto deployenoughinstruments
to constructan arraycapableof mappingan areaa few
hundredkilometers
ona side,it becomes
prohibitivefor areasonemegameter
andlargerin scale,eventhough
manyfewertomography
instruments
arerequiredthan conventional
pointmeasurements.
Onepossible
ap-
proachto makehigh-resolution,
three-dimensional
mapsof largeareasof theoceanis to develop
a hybrid
system,in whicha combination
of mooredinstruments
and preciselypositionedsourcesand/or receivers
suspended
fromshipsareusedtogenerate
a dense
setofcrossing
raypaths.Simulations
indicate
thatfouror
fivetransceivers
mooredin a largearraytomakelong-term
measurements
oftheaverage
oceanstructure
could
becombined
withperiodiccruises
withship-suspended
sources
and/orreceivers
to giveexcellent
mapsof a
squaremegameter
of ocean.It will beessential
in suchexperiments
to usedataassimilation
techniques
to
combinethe dataobtainedasa functionof time by the shipinto a numericalmodelof the ocean.Other data
types(e.g.,satellite
altimeter
data)canbeassimilated
at thesametimeto improvetheresulting
mapsof the
ocean.
9:50
S4. The acousticstochastic
inversepeoblem.Terry E. Ewart (AppliedPhysicsLaboratoryand Schoolof
Oceanography,
University
of Wgshington,
Seattle,
WA 98105)
It hasbeendecidedthatthestatistics
of thephase,complexamplitude,andintensityfluctuations
thatresult
fromwaves
propagating
in mediawithrandomindexof refraction
inhomogeneities
canbepredicted.
In fact,
theemphasis
hasbeenrefocused
fromthedevelopment
ofthetheorytoa requirement
tounderstand
morefully
the statisticsof the oceanmedium.An excitingresultof the success
of the theoreticalpredictionsis the
possibility
of invertingacoustic
measurements
to obtainthestatistics
of the oceanmedia.In thestochastic
inverseproblem,oneobtainscoefficients
of statistical
modelsof theacoustic
indexor refractionusingoptimization techniques.
Thesetechniques
requirethat deterministic
signals,e.g., tides,be treatedformallyin a
differentmannerfromstochastic
signals,e.g.,internalwaves.Examplesof theinverseproblemwill be given
fromoceanandnumericalexperiments.
Modelsoftheoceanicinternalwave,finestructure,
andtidalprocesses,
obtainedfrommeasured
acoustic
fluctuations,
arecompared
with thosemeasured.
A discussion
of thefuture
expectations
including3-D considerations
will be presented.
ContributedPapers
10:15
S5. Simulated reciprocal transmissionsthrough a three-dimensional
sound-speed
and current structure.JamesA. Mercer (Applied Physics
Laboratory, College of Ocean and Fishery Sciences,University of
Washington,Seattle,WA 98105)
A computercodethat integratesHamilton'sequationsfor a continu-
S43
J.Acoust.
Soc.Am.Suppl.1,Vol.82,Fall1987
ouslydefinedmediumwasusedto modela reciprocaltransmission
experi-
mentalonga 2000-kmpath.The description
of themediumincludedthe
three-dimensional
sound-speed
and currentstructuresof four mesoscale
eddiesand a westernboundaryjet. Eigenraysfor the reciprocaltransmissionsare determined,displacements
are compared,and the criticalphysical processes
are identified.Travel time resultsare comparedwith those
from lessrealistic two-dimensionaland one-dimensionalcodes. [Work
sponsoredby ONT. ]
114thMeeting:
Acoustical
Society
ofAmerica
S43
10:30
$6. A discussion of three-dimensional wave propagation effects.
Ding Lee, Paul D, Scully-Power,George Botseas(Naval Underwater
SystemsCenter,New London,CT 06320), and William L. Siegmann
( RensselaerPolytechnicIntitute, Troy, NY 12180)
In mostenvironments,the predictionof acousticwavepropagationis
carriedout with two-dimensionalpropagationmodels.This shouldNOT
misleadanyoneto believethat three-dimensionalmodelsare not needed.
In thispaper,sound-speed
informationfromeddymodelsisusedto examinethree-dimensional
effects.
This examination
wascarriedout employing the IFD (two-dimensional)and the FOR3D (three-dimensional)
models. A set of numerical results from these two models will be dis-
cussed.
Interestingfindingswill bereported.Thesefindingsprovidestimulation for continuedthree-dimensional
modeldevelopment.
specificsituation.In part ( 1) of this paper,the caseof individualmode
propagation
in SOFAR channelisinvestigated
by analyzingthedifferent
valid ranges.In part (2), the effectsof a mesoscale
oceaneddyon mode
propagation
by usingPE (IFD) codearediscussed.
The maingoalis to
findout if the modecouplingmatrixis sensitive
enoughto applyin the
"matched-field"methodfor the purposeof oceantomography[Work
supportedby NRC. ]
11:15
S9. Error estimatesfor 3-D computationalschemesof wavepropagation.
GeorgeH. Knightly and Donald F. St. Mary (Center for Applied
Mathematics and Mathematical Computation, Department of
Mathematics,University of Massachusetts,Amherst, MA 01003 )
For severalcomputationalschemesin underwaterwavepropagation,
10:45
S7. Coherenceloss modelingusingthe PE method.F. D. Tappert
( Universityof Miami, Applied Marine Physics,Miami, FL 33149)
Scatteringby volumefluctuationsof soundspeedand by boundary
roughness
causesa lossof coherenceof propagatingcw signalsin the
ocean.A 3-D parabolicequationmodelfor the coherentGreen'sfunction
(p) isderivedthatdescribes
angle-and
depth-dependent
scattering
loss.
Byintegrating
overa narrowsectorof azimuthalangles,it isshownthata
2-D verticalplanemodelgivesan excellentapproximation
for forward
scatteringloss.The resulting2-D ew modelis efficientlysolvednumericallyby generalizing
thesplit-stepFourieralgorithmto performmultiple
local Fourier transformsby windowingin depth, transformingfrom
depthto verticalangle,applying
anangle-dependent
filter,summing
over
layers,andfinallyinverseFouriertransforming.
For roughsurfacescattering,thismethodgivesa lossthat islinearin thegrazinganglefor small
angles,in agreement
with Marsh-Mellontheory.
11:00
$8. The PE methodand the oceantomography.E. C. Shang(NOAA,
WavePropagationLaboratory,Boulder,CO 80303)
It waswell known that both the ray methodand the PE methodcan
handle wave propagationproblemsin 3-D environments,but both of
themareapproximations
of the waveequation.In ray method,the diffraction termwasdiscardedsoit isgoodfor highfrequency;in PE method,the
term of second-order
derivationon rangewasdiscardedsoit is goodfor
narrow angle.The accumulatedphaseerror restrictsthe rangewithin
whicheachmethodis valid.Onehasto choosea bettermethodto adapta
$44
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
stabilityand consistency
boundsare knownthat imply corresponding
ratesof convergence.
It isshown,in somecases,
howthisinformation
can
beimprovedto yieldexplicitboundsfor thetruncationerrorbetweenthe
exactsolutionof a continuousproblemand the approximatingsolution
generatedby the computationalscheme.In particular,thoseboundsare
demonstrated
for an implicitfinitedifference
schemein threedimensions.
11:30
S10. Three-dimensionalunderwater acoustic propagationthrough a
steady shear flow. J. S. Robertson (Department of Mathematics,
U.S.M.A.,
West Point, NY
10996-1786), M. J. Jacobson, and W.
L. Siegmann (Department of Mathematical Sciences, Rensselaer
PolytechnicInstitute,Troy, NY 12180-3590)
Previousstudiesby theauthorshaveincorporated
currenteffectsinto
parabolicapproximations,whenthe currentvectorlay within the vertical
source-receiver
plane.Here, the currentand the source-receiver
plane
are not constrainedto be parallel, and thus a solutionto a fully three-
dimensional
problemisobtained.A classof sound-speed
profilesisexaminedthat is advectedin a steady,depth-dependent
oceancurrent.A cw
sourceis submerged
betweena horizontalpressure-release
surfaceand a
horizontalbottom.Whencertainasymptoticorderconditionson derivativesof thecurrentand soundspeedaresatisfied,
parabolicapproximations of canonical form result. Furthermore, if additional restrictionson
azimuthalderivativesapply,the azimuthalmodesare decoupledso that
the azimuthalangleappearsonly as a parameterin the parabolicequations.Thus the pressurefield may be calculatedin decoupledvertical
planes,i.e., in an N X 2-D approximation.Severalexamplesarediscussed,
andtheacousticaleffectsof currentstructureareillustrated,with emphasison azimuthaldependence
of relativeintensity.[Work supported
by
ONR. ]
114thMeeting:Acoustical
Societyof America
$44
WEDNESDAY MORNING, 18 NOVEMBER 1987 POINCIANA ROOM, 9:00A.M. TO 12:00NOON
SessionT. ArchitecturalAcousticsIII: Analysis;EducationalFacilities
Ewart A. Wetherill, Cochairman
F•/ilson
lhrig & Associates,
Inc., 5776Broadway,
Oakland,California94618
RichardM. Guernsey,Cochairman
CedarKnolls•4coustical
Laboratory,
9 SaddleRoad,CedarKnolls,NewJersey
07927
Chairman's Introduction--9:00
Invited Paper
T1. Calculation
of free-field
deviation
in an anechoic
room.Ji-qingWang(instituteof Acoustics,
Tongji
University,
Shanghai,
People's
Republicof China200092)andCai Biao(Jiaotong
Universityof Eastern
China,Nanchang,People'sRepublicof China)
After a reviewof variouscalculationmethodscurrentlyavailablefor free-fielddeviation(in dB) in an
anechoic
room,theauthors
present,
inthispaper,a moreprecise
andrationalcalculation
ofthesoundfieldby
solving
waveequations
in consideration
of theinterference
of firstreflections
only.In thecaseof puretone,the
phasefactorplaysan importantrolein the calculation;therefore,the free-fielddeviation(in dB) calculated
alsodepends
onthesource
position,
measuring
direction
anddistance
fromthesource,
andthefrequency
used
in thetest,besides
otherfactorssuchasthedimensions
oftheroomandsoundabsorption
characteristics
of all
theboundary
surfaces.
For a broadband
noise,thecalculation
becomes
simplersincethephasefactorcanbe
ignored,
anda general
equation
ofsucha calculation
isgivenforanysource
position
anddifferent
combinations
of boundary
absorption.
Theresults
of thecalculation
canbeshownin a diagramwiththeaidofa microcomputer,and,hence,
a three-dimensional
free-field
scope
wouldbeveryusefulasa guideline
todesign
andtouse
an anechoic room.
ContributedPapers
9:35
T2. A graphicrepresentation
of acoustics
t•ing ray tracing.Philip
R. Thompson(Departmentof Architecture,Massachusetts
Instituteof
Technology,
Cambridge,
MA 02139)
Thisresearch
detailsthedevelopment
of a computermodelthatdisplaysthe propagationand reverberationof soundwithin an architectural
enclosure.
Thevisualrendering
of acoustics
isdoneby simulating
sound
fieldsusinggraphicalray methods.
Unlikemanyotheracoustical
raytracingmethods,
in thisconcept,
raysareemittedfroma receiving
point
andtracethepathstothesoundsource
soastoproduce
a pictureofwhata
listener
hears.Thisthree-dimensional
reeursive
ray-tracing
algorithmhas
beencombinedwith an acoustical
model,utilizingspecularandfirst-orderdiffuse
reflections,
toproduce
animage(or series
ofimages
) depicting
the locationsof real andvirtualsources,
the time delaysin whichthey
arrive,andtheirapproximate
energylevels.The free-pathlengthsof the
raysaresortedintoframesthatproduce
an animationsequence
demonstratingthepropagation
of a soundfieldtowardsthelistener.The sources'
emittedenergyandsubsequent
attenuations
alonga ray'spathresultin an
intensity,whichis thendepicted
asa colorat a pixelon the computer's
monitortocompose
animage.Whiletheprogramismeantto runonmost
anymachine,
a workstation
ispreferred
sincea relatively
largeamountof
computation
(involving
hundreds
of thousands
ofrays) isrequired.
The
purpose
of thisanalysis
toolis to elucidateandverifyour perceptions
of
room acoustics
throughthe mostreadilyunderstandable
visualmeans.
S45
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall 1987
[Work supported
by MIT ProjectAthenathroughthe ComputerResourceLab in theSchoolof ArchitectureandPlanningandby theRobert
B. NewmanMemorialFellowship.]
9:50
T3. Effect of flaidel--stracturaicouplingon soundwavesin an enclosure
in low-frequencyrange.Pan Jieand D.A. Bies(Universityof Adelaideo
Departmentof MechanicalEngineering,
GPO Box No. 498, Adelaide,
S.A. 5001, Australia)
The acousticpropertiesof individualnormalmodesin a rectangular
panel-cavitysystemwereinvestigated
experimentally.The systemconsisteda heavy five-sidedconcretebox closedon the sixth side with a test
panel.Experimentalevidencein thispaperrevealsthedependence
of the
modaldecaytimeof soundwavesin theenclosure
uponthemodalcharacteristicsof the testpanel,suchas the modalcouplingfactors,resonance
frequencies,
andmodaldecaytimesofthetestpanel.Theresults
ofexperimentalmeasurements
are usedto verifysomeof the previoustheoretical
predictions.
The agreement
betweenthemeasured
andcalculatedacousticalmodaldecaytimeshowsthat themodalcouplingtheorycanbeusedto
evaluate thc sound wave behavior in those enclosures,in which the cou-
plingbetweenfluid borneand structureborneacousticalwavesis modal
and wherethe classicalmodelbasedon the locallyreactiveboundary
assumptiondoesnot apply. The phenomenonof the maximumsound
energyabsorptionby the panelwasalsoobservedin the experiment.
114thMeeting:Acoustical
Societyof America
S45
10:05
10:20
T4. Effect of fluldal-structural couplingon the acousticaldecaysin a
reverberation room in high-frequencyrange, Pan Jie and D. A. Bies
(Universityof Adelaide,Departmentof MechanicalEngineering,GPO
TS. An indirect boundary integral equationmethod for architectural
acoustics.D. K. Holger (Department of EngineeringScienceand
Mechanics,2019 Black EngineeringBuilding, Iowa State University,
Box No. 498, Adelaide, S.A. 5001, Australia)
Ames, IA 50011)
The effectof thecouplingbetweena soundfieldandtestpanelsupon
theirdecaybehavioris investigated
in high-frequency
range.Quasitransientsolutions
of theaverage
energies
in theroomandthepanelsareused
A numerical
methodandtheresulting
computer
programfor predictionofinterioracoustic
fieldsaredescribed.
The methodisbaseduponan
indirectboundaryintegralequationformulationof theHelmholtzequation usinghybridlayer potentials.The computerprogramincorporates
generalboundaryconditionsdirectly, and utilizespiecewiseconstant
variableapproximations.
It is capableof predictingthe steady-state
response
of enclosures
with finiteimpedance
boundaries,
vibratingboundaries,andmultipleinteriorsources.
Numericalresultsarepresented
for
theaeonsticfieldinsidea rectangularprismundervariousboundaryconditionsandwith variousexcitations.Apparentlimitationsof the current
programarediscussed,
andvariouspotentialapplications
in architectural
acoustics
andnoisecontrolare suggested.
[Work performedat the Institutt for Teleteknikk,NorgesTekniskeHogskole,Trondheim,Norway
and supportedby NTNF. ]
to estimatethe reverberationtimesin the room and to calculatethe decay
curvesofa testpanel.Experiments
areconducted
to verifythesesolutions.
The estimatedand measuredresultsare in goodagreementin high-fre-
quencyrange,which indicatesthat the averagedecaybehaviorof the
roomand panelscan be analyzedin termsof the averagemodalparameters.The amalgamationof the averagemodal parameters(of the test
panelsand the reverberation
room) canbe relatedto the Sabineabsorptioncoefficient
as•bof thepanels.Thisresultprovidesa possible
interpretation for the as•b of a modallyreactivesurfaceand suggests
a way to
estimatethis quantityby statisticalenergyanalysis(SEA) method.The
dependence
of the as•buponthe roomproperties,in whichthe panelis
measured,is demonstrated
bothexperimentally
and analytically.
10:35-10:45
Break
10:45
T6. Acoustical considerationsin designof semienclosedsmall arms
training facility. Felix Sachs,Nelson Lewis, and GeorgeLuz (BioAcousticsDivision, U.S. Army EnvironmentalHygiene Agency,
School.In additionto classrooms,
thebuildingincludesscreening
rooms,
edit rooms,a recordingstudio,an AM/FM radiostation,two television
studios,and a soundstage.The designapproachis describedand the
completedresultsare analyzed.
AberdeenProvingGround, MD 21010-5422)
Semienclosed
smallarmstrainingrangescombinebullettrapfeatures
of an indoorrangewith theventilationof outdoorranges.Acousticreverberationof indoorrangesanddirectivityeffectsof outdoorrangesarealso
combinedin the semienclosed
range.Whendesigners
of a semienclosed
11:30
rangefailedtodesign
fortheacoustic
directivity
ofguns,
community
noise
levelsincreased
andresidents
whohadadaptedto a long-standing
noise
T9. RASTI for speechisolationevaluation.Klaus Hojbjerg(Brueland
Kjaer Instruments,
Inc., 185ForestStreet,Marlborough,MA 01752)
environment
fromanoutdoorrangebegancomplaining.
Personnel
onthe
firingline alsonoticedan increase.Measurements
at the firingline demonstrateda sevenfold
increasein the occupational
noisedose,whilemea-
In openoffices,thereis a demandfor speechisolation.As it becomes
moreimportantto avoidsurveillance
from outsideconference
rooms,a
reliablemethodof evaluatingthespeechsecuritybecomes
necessary.
Re-
surements made out to 500 m demonstrated an 8-dB increase in the com-
munitynoiseexposure.
The 8-ribincreasewasattributedto thereflection
of theforwardweaponreportfromthebullettrapbaffles.
The increase
in
noiseexposureat the firing line wasattributedto reverberationfrom the
sidewalls and roof of the semienclosed
range.The measuresto reduce
boththe occupational
and communityexposures
are addressed.
search has shown that transmission loss or the articulation index method
doesnotgiveenoughinformation.
Thisisbecause
speech
intelligibility,
or
ratherthelackof speech
intelligibility,depends
on morethanthesignalto-noise ratio. The RASTI
method takes into account the effects of reflec-
tions,reverberation,and noise.By usingthe low end of the RASTI scale,
thelackof speech
intelligibility
canbedetermined.
Thispaperdescribes
the measurement,
usingelevatedsignallevels,as well as measurement
results.
11:00
T7. Acoustical
designfor theMerkin ConcertHall andtheHebrewArts
School.PeterJ. George(PeterGeorgeAssociates,
Inc.,34 West17th
Street,New York, NY 10011)
11:45
Sound
control
issues
werecritical
inthedesign
ofthemultistory
build- TI0. Controllingthe shapeof an aeonsticspectrumautomaticallyin
ingthatrequiredrelatively
light-weight
construction.
The AnneGoodmanRecitalHall waslocateddirectlyabovethe Metkin ConcertHall.
Dance
studios
wereadjacent
toPianoClassrooms,
whichwereadjacent
to
Practice
Rooms.
Comparison
ismadebetween
thetechniques
used
onthis
buildingandthosefortheneighboring
JuilliardSchool.
11:15
TS. Acousticaldesignfor theTischSchoolof the Arts. PeterJ. George
(Peter George Associates,Inc., 34 West 17th Street, New York, NY
10011)
New York University'sTischSchoolof the Arts hasmovedinto a 12storybuildingthat wasguttedandrecycledto providea newhomefor the
S45
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall 1987
vaeiousSlmeea.Thor Carlsen and Richard J. Peppin (Scantck Inc./
NorwegianElectronicsa/s, 51 Monroe Street,Suite 1603,Rockville, MD
20850)
Often,whena roomis excitedby a specified
spectrum,the resulting
spectrumdiffersin shapefrom that desired.Causedby the impedanceof
the spaceand by the objectswithin, in the past,the changehasbeen
accounted
forbytheuseof a spectrum
shaperbeforethenoisegenerator,
whichwasmanuallyadjusted
sothat the desiredshapeandlevelof the
outputwasachieved.This paperpresents
a discussion
of a bus-controlled
spectrumshaperthat, in conjunctionwith a computercontrolledrealtime analyzer,allowsthe shapeof the desiredspectrumto be achieved
withoutoperatorintervention.Usesfor vibrationexcitationwill alsobe
discussed.
114thMeeting:AcousticalSocietyof America
S45
WEDNESDAY
MORNING,
18 NOVEMBER
1987
TUTTLE SOUTH ROOM, 9:00 TO 11:00 A.M.
SessionU. Noise III: Alert and Notification Systems
T. JamesDuBois, Chairman
SouthernCalifornia Edison,2131 Walnut GrooeAoenue,Rosemead,California 91770
Chairman's
Introduction--9:00
Invited Papers
9:05
U1. The FederalEmergencyManagementAgency'salert and notificationsystemsreviewi•rogram.Craig
S. Wingo (FederalEmergencyManagementAgency,Washington,DC 20472)
Nuclear powerplantsthroughoutthe United Statesare requiredby the Nuclear RegulatoryCommission
(NRC) to providethe meansfor earlynotificationandclearinstructionof thepopulacewithinthe 10-mile
radius EmergencyPlanningZone (EPZ) around each plant. The regulationsand the Federal Emergency
ManagementAgency's(FEMA) technicalprogramfor reviewingand approvingalert and notificationsys-
temsare discussed
in this paper.The FEMA programconsists
of an acoustical/engineering
reviewof the
systemdesign,coupledwith a telephonesurveyof residentsof the EPZ followingactivationof the systemto
determineitseffectiveness.
To date,systemdesignshavebeensubmittedfor everynuclearpowerplant in the
nation.The engineering
designreviewhasbeencompletedat 68 sites,anda telephone
surveyhasbeencompleted at 63 sites.Recently,the technicalstandardsagainstwhichalert and notificationsystemsare reviewedhave
come
under
scrutiny
inAtomic
Safety
andLicensing
Board
litigation
andFEMAhasdefended
theadequacy
of
thecurrentstandards.
Effortsareunderwayto placetheOutdoorSoundPropagation
Modelusedin thealert
and notificationsystemreviewsinto FEMA's IntegratedEmergencyManagementInformationSystemfor
applicationto civil defenseprograms,hazardousmaterialsprogram,and other programsin and outsideof
FEMA.
9:30
U2. Designof alert and notificationsystems.Louis C. Sutherland (Wyle Laboratories,128 Maryland Street,
El Segundo,CA 90245) and Eric Stusnick(Wyle Laboratories,2001 JeffersonDavis Highway, Arlington,
VA 22202)
Alert
and
notification
systems
arerequired
bytheNuclear
Regulatory
Commission
around
nuclear
power
plantsto providea meansof alertingthepublicwithina 10-mileradiusof a possible
emergency
conditionthat
may requireevacuation.The mostcommonmethodof accomplishing
this is throughthe useof audiblesignals
from high-poweredsirens.The basicproblemsinvolvedin the designof suchsystemsare discussed.
These
problemsincludespecification
and validationof the sirenoutputsignals,the predictionand validationof the
sirensignalas receivedin the community,and nonacoustic
factorssuchas sireninstallationand control.
Generalcharacteristics
of currentlyavailablesirensystems--bothelectromechanical
and purelyelectronic
types---arealsobrieflyreviewed.Statisticalaspectsof short-term(secondto second)and long-term(day to
day) variations
in sirensignallevelsreceived
in thecommunityarediscussed,
andthisvariationin thewarning
signallevelis evaluatedwith respectto overallsystemeffectiveness.
Othermeansof conveying
thewarning,
includingthepresentation
of alteringmessages
overautomaticallyenergizedradiosandsiren-equipped
emergencyvehicles,are alsobriefly considered.
9:55
U3. Evaluationof sirenalert notificationsystems.Van M. Lee (Analysis& Computing,Inc., Hicksville,NY
11802)
This paperdescribesthe essentialelementsin evaluatingthe effectiveness
of a large outdoorfixed siren
warningsystem,thestate-of-the-art
of thecomponent
evaluationprocesses,
andthepotentialimprovements
in
the future.The essentialcomponents
in evaluatingthe coverage--thepercentageof populationwithin the
planningzonealerted-•consistof: sirenacousticperformance(dB versusfrequencyversusdirectivity), site
terrainandmeteorological
effectsonsoundpropagation,
populationstatistics(activitypatternsandagedistributionby household
size), buildingattenuationeffects,and activity-soundlevelresponse
relationships.
The
lack of standardtest procedures,whether laboratoryor field, and data reportingformatshas led to many
disputesconcerningomnidirectionaland directionalsirens.Standardmethodsfor site qualification,siren
testing,and data reportingsimilar to ANSI S1.34 (1980) and S1.35 (1979) are discussed
in relationto their
effecton thedesignandevaluationof sirensystems.
Also discussed
arethe effectsof air absorption,wind and
temperaturegradients,operatingcharacteristics
(omnidirectionalor rotating), and terraineffects,including
Rasmussen's
applicationof barrierdiffractionandimpedancegroundeffects.By correlatingthephysicalsiren
S47
J. Acoust.Soc.Am.Suppl.1, Vol. 82, Fall 1987
114thMeeting:AcousticalSocietyof America
S47
soundlevelcoverage
tothesocialresponse
levelof thealertedpopulation,
a systematic
methodology
ispresented, which evaluatesthe overalleffectiveness
of a largeoutdoorsirenalert system.
10:20
U4. Outdoor sirens:How do they work for peopleindoors?David N. Keast (HMM Associates,inc., 336
Baker Avenue, Concord, MA 01742)
Peopleare normallyindoorswherethe soundsfrom outdoorwarningsirensare greatlyattenuated
by
buildingstructures.
Nevertheless,
practicalexperience
andthe resultsof testsby the FederalEmergency
Management
Agencyandothershaveshownthat sirensounds
arequiteeffective
for alertinglargepopulations-including
thoseindoors.
Whyisthisso?Based
upondatain theliterature,
threepossible
explanations
areexamined
in thispaper:( l ) thepossibility
thatthesounds
fromsirensoutdoors,
eventhoughattenuated
throughbuilding
structures,
arestillsufficient
to directlyalertpeople
indoors;
(2) thepossibility
thatpeople
indoorsaremoreresponsive
to sirensounds
thanpeopleoutdoors;
and(3) thepossibility
thatpeopleindoors
arealerted
byotherpeople
whoareoutdoors
whentheyhearthesirensounds.
Thisexamination
indicates
that
all threemechanisms
couldbecontributing
to theeffectiveness
of sirensounds
indoors.
Theirrelativesignificanceisnotknown,butprobablyvarieswithgeographic
location,weatherconditions,
andtimeof day.
ContributedPaper
10:45
sign,theimportance
of finite-amplitude
effectshasbeenneglected
in the
US. The influenceof high-intensitysoundson the performanceof air
warningsirens.FredericG. Pla (SverdrupTechnology,Inc., NASA
LeRC Group, 16530 CommerceCourt, P.O. Box 30650, Midpark
Branch,MiddleburgHeights,OH 44130)
recentpast,eventhougha reviewof earlierworksshowsthat researchers
suchasReyleigh,in 1903,King,in 1919,andlater,Hart, in 1926,noticed
the extra acousticlossesassociated
with high-intensity
soundsources.
Comparisons
between
linearandnonlinear
models
ofwavepropagation
in
a sirenhornillustratethe importanceof thesetypesof losses,
andshow
how theycanbe minimized.Acousticsaturation,whichlimits the sound-
Theuseofsirens
asairwarning
devices
hasbeenwidespread
forseveral hundredyears.Due to theveryhighsound-pressure
levelsgenerated,
finite-amplitude
effectscanresultin largelosses
leadingto poorsound
high-intensity
soundsource,
andtheimplications
of finite-amplitude
ef-
generation
efficiency.
Althoughmuchwork hasbeendoneon sirende-
ment are also discussed.
WEDNESDAY
MORNING,
18 NOVEMBER
1987
pressure
levelthatcanbeperceived
bya receiverat a givendistance
froma
fectsontheratingofhigh-intensity
soundsources
in a laboratoryenviron-
TUTTLE CENTER ROOM, 9:00 TO 11:50 A.M.
SessionV. PhysicalAcousticsIll: Scattering,Diffraction, and Radiation
Ronald A. Roy, Chairman
Departmentof MechanicalEngineering,MasonLaboratory,Yale University,9 HillhouseAvenue,New Haven,
Connecticut 06520
Chairman's Introduction--9:00
ContributedPapers
9:05
V1. Monostatic angular distributionsand their relation to resonancesin
acoustical scattering from fluid loaded solid elastic objects.
G. Gaunaurd(NSWC, White Oak, SilverSpring,MD 20903-5000)and
M.F.
Werby (NORDA, NSTL, MS 39529)
It is possibleto detectresonances
from backscattered
echoes(form
functions)by varyingthe nondimensional
frequencykL/2 in smallincre-
ments.Thisgivesrisetoa familiarpatternofnullsfollowedbya sharprise
for the sphericalcaseand similarresultsfor the spheroidal
case.This
S48
J. Acoust.Soc. Am. Suppl.1, Vol. 82, Fall 1987
approach,however,limitsoneto oneaspectanglefor three-dimensional
nonspherical
problems
andoftenentailstedious
andtimeconsuming
calculationsto findtheoftennarrowresonance
regions.Anotherapproach
suitable
forthree-dimensional
problems
istoexamine
closely
spaced
monostaticangulardistributions
enablingoneto lookfor possible
resonances
overa continuous
rangeof aspectangles.This methodis usedto examine
scattering
fromsolidsteelspheroidal
shells.TheresultsindicatethatRayleightyperesonances
areaspectangledependent
in contrastto ourrecent
resultson spheroidal
shells.The resultsareconsistent
withthestanding
waveinterpretationof resonances
proposedby useearlierfor shellsand
employedin workon materialpropertiesof solidelasticspheroids.
114th Meeting:AcousticalSocietyof America
$48
9:20
V2. Acousticscatteringfrom an elastic prolate spheroidin a shallow-
water waveguide.Gary S. Sammelmannand Roger H. Hackman
(Physical AcousticsBranch, Naval Coastal SystemsCenter, Panama
City, FL 32407)
The bistaticscatteringof a broadbandacousticpulsefrom an elastic
prolatespheroidin a shallow-water
waveguide
isstudied.The calculation
is basedon the formalsolutionto the scatteringin an inhomogeneouslayeredwaveguidepresentedat a previousmeetingof the AcousticalSociety JR, H. Hackman and G. S, Sammelmann,J. Acoust. Soc. Am.
Suppl.1 81, S42 (1987) ]. The waveguide
is assumedto beboundedfrom
aboveby a soundsoftair-seawaterinterface,and from below,by a rigid
sediment-seawater
interface.The soundspeedis takento bea monotonically decreasing
functionof depth.The emphasisof this studyis on extractingelasticinformation
fromthescattered
waveform.
Theimportance
of the rescattering
of the acousticpulsebetweenthe boundariesand the
targetis alsostudied.
due to leaky Lamb wave generation,too). This simpletechniquehas
provedto beveryusefulin materialevaluationvia measuring
bothsurface
and Lamb wavevelocities.On the otherhand,a comprehensive
experimentalstudy[M. deBilly, L. Adler, andG. Quentin,J. Acoust.Soc.Am.
72, 1018(1982) ] showedmuchstrongerbackscattered
signalsthan predictedlater by theoreticalworksbasedon back reflection.New experimentalresultsare presenteddemonstrating
that this back reflectionis
negligiblein the backwardsignal,which is simplybackscattering
from
inevitablematerialinhomogeneities
greatlyenhanced
by surfaceor Lamb
wavegeneration.Therefore,besidemeasuringmacroscopic
elasticpropertiesin the previouslysuggestedway, the backscatteredsignalcan be
usedtocharacterize
surfaceandnear-surface
materialinhomogeneities
as
well. [Thisworkwassupported
by theU.S. Departmentof Energy,Basic
EnergySciences,
Grant DE-FG02-84ER45057.A004.]
10:20
V6. Measurements of Rayleigh wave scattering at a corner. Peter
B. Nagy and Laszlo Adler (Departmentof WeldingEngineering,
The
Ohio StateUniversity,Columbus,OH 43210)
9:35
V3. Acoustic scattering from large aspect ratio, axisymmetric shells.
Roger H. Hackman and Douglas G. Todoroff (Physical Acoustics
Branch,Naval CoastalSystemsCenter,PanamaCity, FL 32407)
The spheroidal-coordinate-based
transitionmatrixhasbeensuccessfully appliedto the solutionand the analysisof the acousticscattering
from largeaspectratio solids[R. H. Hackmanand D. G. Todoroff,J.
Acoust.Soc.Am. 78, 1058-1071 (1985)]. However, this approachrequiredspecialcaredueto the existence
of elasticstatesthat wereweakly
coupledto theexternalacoustic
field.Here,a newversionof thespheroidal formalismis presented,onewith improvedstabilityand which is better suitedto thin shells.Thisapproachisappliedto theacousticscattering
froma largeaspectratio,elasticprolatespheroidal
shellof constantthickness.Theoreticalpredictionsare comparedwith experimentalmeasurements,anda physicalexplanationis givenfor the moreprominentfea-
Theproblemof Rayleighwavescattering
in a homogeneous,
isotropic
wedgeby experimental
meanswasinvestigated.
For anincidentRayleigh
wave,reflectedandtransmittedRayleighwavesare generated,aswell as
longitudinal
andtransverse
cylindrical
bulkwavesinitiatedbythevirtual
sourceat thecornerline.Sector-shaped
testpieceswereused,whichfocusedbackthedivergingbulkwavesto thesamecornerlineafternormal
reflectionat the cylindricalsurface.By this simplegeometry,both the
phaseandamplitudeof all fourcomponents
wereableto be measured.
Experimental
results
arepresented
to showthevaryingenergypartition
amongthese
modes
asafunction
ofwedge
anglefrom90øto 150øinaluminum.Furthermore,theRayleighwavereflection
andtransmission
results
arecompared
to recenttheoretical
predictions
by Gautesen[ WaveMotion 9, 51-59 (1987)]. [This work was supportedby the U.S. Depart-
ment of Energy, Basic Energy Sciences, Grant DE-FG0284ER45057.A004. ]
tures in the backscattered formfunction.
10:35
9:50
V4. Comparisonof quadraticand piecewise-constant
boundaryelement
solutionsof the surfaceHelmholtz equation.JosephJ. Shirron (Sachs/
Freeman Associates,Landover, MD 20785)
A comparison
of the accuracyandcomputationtime of two different
boundaryelementsolutiontechniques
for thesurfaceHelmholtzequation
of a rigidscattererispresented.
In thesimplest
case,thebody'ssurfaceis
represented
by an assemblage
of planartriangles,overwhichthesurface
pressure
istakentobeconstant.
In themoresophisticated
case,quadratic-
isoparametric
elements
areused.Results
arepresented
forthecomparison
of ratesof convergence
withmeshsizeandCPU timesfor thetwo methods.The effectsof varyingthe orderof Gaussianquadratureare shown.
Furtherresultsaregivencomparing
theefficiency
of Schenck's
algorithm
for eliminatingthenonuniqueness
problemat thebody'sinterioreigenvalueswith the modifiedGreen'sfunctiontechniqueof D. S. Jones.The
quadratie-isoparametric
solutionmethodtogetherwith Schenck's
algorithm isfoundto bethe moreei•cientmeansof obtainingan approximate
solutionto thesurfaceHelmholtzequation.[ Work supported
by Naval
ResearchLaboratory,Washington,DC. ]
V7. Farfieldpatternsof rigid nonaxiallysymmetricobstacles:
Example
calculationsusingthe Watermanschemefor approximationof the T
matrix. Angie Sarkissian(Sachs/Freeman
Associates,
Landover,MD
20785) and Allan G. Dallas (Code 5131, Naval ResearchLaboratory,
Washington,DC 20375-5000)
To our knowledge,
therehavebeenno reportsof numericalapplicationsof the Watermanschemeto rigid scattersof nonaxiallysymmetric
geometry.
Here,theresults
ofcomputations
for variousslender
obstacles
of thissortaredescribed.
Emphasis
is placedupontheamountof work
required
forsuchcalculations
(relativetothatnecessary
foraxiallysymmetricshapes)
anduponspecific
details,
suchasthenumbers
ofspherical
wavesand quadraturepointsrequired.
10:50
VS. The effectof finite surfaceacousticimpedanceon soundfieldsneara
smooth diffracting ridge. Ji-xun Zhou, James A. Kearns, Yves
H. Berthelot,and Allan D. Pierce (Schoolof MechanicalEngineering,
GeorgiaInstituteof Technology,
Atlanta,GA 30332)
10:05
VS. Another look at the Rayleigh angle backscattering.Peter B. Nagy
and Laszlo Adler (Department of Welding Engineering,The Ohio State
University, Columbus,OH 43210)
The incresedbackscattering
from a liquid-solidinterfaceat the Rayleigh angleis a well-knownindicationof leaky surfacewave generation
(similarphenomena
wereobserved
from thin platesimmersedin liquid
$49
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
Laboratoryscaleexperiments
usingsparksources
arebeingconducted to studylong-range
propagation
of soundoverhillsandvalleys.The
effectof thefiniteimpedance
of thediffraeting
scaledhill on theacoustic
fieldisinvestigated,
witheitherplywoodor plywoodcovered
withcarpet.
Particularattentionis givento the caseof smallgrazinganglesof incidenceof the soundwaveon the diffractingsurface.The modelof Delany
andBazleyis usedto determinethe impedance
of thematerialfrom the
valueof the effectiveflow resistivitya. The insertionlossof the scaled
ridge
isinferred
frommeasurements
oftheratiooftheFourier
transforms
of thediffractedpressure
fieldto that of the freefield,with subsequent
114thMeeting:Acoustical
Societyof America
S40
digitalsignalprocessing
performed
in thefrequency
domain.Experimental dataare comparedwith thetheoryof matchedasymptoticexpansions
[J. Acoust.Soc.Am. Suppl. I 79, S30 (1986) ] for situationswherethe
diffracted
acoustic
pressure
ismeasured
eitheralongtheridge,oralonga
verticalaxisat theapexor behindtheridge.[Worksupported
by NASA,
LangleyResearchCenter.]
Soundradiationby finitecylindrical
stiflened
shells,in lightor heavy
fluid,isstudiedusingmodalcalculation.Numericalresultsonpowerradiation,shellquadraticvelocity,and radiationfactorare given,and the
influenceof parameterslike stiffenersdistribution,stiffenerand shell
damping,
typeofexcitation,
etc.,isdiscussed.
Finallytheanalysis
ofshell
modesthat contributemostto the radiationis presented.
It isshown,in
particular,that modeswhosestructurallossesequalradiationlosses
dominate
the powerradiation,
whatever
the fluid (however,
for light
11:05
V9. Diffractionof pulsesat a sharpedge.Gerrit Schouten(Aerospace
Department,Delft Universityof Technology,Kluyverweg1, 2629 HS
Delft, The Netherlands)
fluids,thesemodeshavehighradiationefficiency
andlow radiationefficiencyfor heavyfluids).Thisanalysis
allowstheunderstanding
of radiationcurvesingularities,
andshowsthatcriticalfrequency
phenomena
arecompletely
differentfor heavyandlightfluids.[Work supported
by
the Minist•re de la D•fenseContratD.R.E.T.N ø85-065.]
The closedexpression
for the diffractedfieldof a soundpulseis derived in a straightforwardmannerusingSommerfeld'smethodfor the
generationof many-valuedsolutionsfrom knownone-valuedsolutionsof
thewaveequation.The sphericalprimarywavefrontcarriesa delta-func-
tion disturbance,
whereasthe spindle-shaped
diffractionfront carriesa
square-root
singularityboundingthe filleddiffractionregionwheretwo
dimensional
aspects
aredominating.
Integration
w.r.t.timeoffiringofthe
pulseyieldsthe transientbehaviorof a hydrodynamic
switch-onsource
witha unit-step
wavefront.Thewell-known
resultof Cagniard( 1935) is
thusreproducedin a directway. Plotsof the velocityfield insidethe
diffractionregionshowthe peculiarities
of the transitionfrom the wave
solutiontothesteadyLaplacesolution.Applyingthemethodofdescent
to
thethree-dimensional
solutions
yieldstheknowntwo-dimensional
equivalents,againin a moredirectwaythanknownfromtheliterature[R. D.
Turner( 1956);H. A. Lauwerier( 1962);E. M. deJager(1964)].
11:35
Vll. On the acousticexcitationsof an elongatedelasticsolid. Kevin
L. Williams,Douglas
G. Todoroff,andRogerH. Hackman(Physical
Acoustics
Branch,Naval CoastalSystems
Center,PanamaCity, FL
32407)
Previously,
an analysisof the acoustically
coupled,axisymmetric,
elasticexcitations
ofa fluid-loaded,
prolatespheroidal
targetwaspresented [D. H. Trivett, G. S. Sammelmann,
and R. H. Hackman,J. Acoust.
11:20
Soc.Am. Suppl.181,S13(1987)]. At thismeeting,
a controversy
arose
VIO. Acoustic power radiation by cylindrical stiflened shells.
asto thephase
speed
oftheelastic
excitations.
Here,directexperimental
B. Laulagnet
andJ. L. Guyader(Laboratoire
Vibrations-Acoustique, andtheoretical
evidence
ispresented
thatsupports
ourcontention
thatthe
InstitutNationaldesSciences
Appliquresde Lyon,69621Villeurbanne
velocity
ofpropagation
oftheelastic
waves
thatpropagate
onanelongatCedex, France)
edsolidtargetat low frequencies
is essentially
thebarspeed.
WEDNESDAY MORNING,
18 NOVEMBER 1987
TUTTLE NORTH ROOM, 9:00 TO 11:50A.M.
SessionW. StructuralAcousticsand Vibration III: Analysisand Measurementof StructuralVibrations
Joel M. Garrelick, Chairman
Cambridge
•lcoustical
•lssociates,
Inc., 54 RindgeAvenueExtension,
Cambridge,
Massachusetts
02140
Chairman's Introduction--9:00
ContributedPapers
9:05
WI. Impact testing of light objects. Mohamed K. Abdelhamid
(Production EngineeringDepartment, Helwan University, Helwan,
Cairo,Egypt) andAnna L. Pate (Departmentof Engineering
Science
and Mechanics,Iowa StateUniversity,Ames,IA 50011)
Thispaperinvestigates
thedesignof a measurement
systemthatmea-
sures
theimpactsignature
ofa lightobject.
Thedesign
isbased
ona freely
supported
piezoelectric
forcetransducer.
Effectsof top mass,basemass,
andstiffness
ofthetransducer
wereinvestigated.
Twomodels
wereusedin
the analysisof the impact,a linearmodelwith a 3 degreeof freedom
systemand a Hertzian model.Using the HertzJanmodel,a criterionfor
choosing
theoptimumsizeof thebasemasswasdeveloped.
Thiscriterion
is basedon the least-square
errorin the forcespectrum.Similarresults
wereobtained
bythelinearmodelandnumerical
simulations.
Experimentalconfirmation
of theresults
wasconducted
usingsmallTeflonandny-
$50
J. Acoust.Soc.Am.Suppl.1,Vol.82, Fall1987
lonballsanda piezoelectric
forcetransducer.
Theresultsagreedwellwith
the modelpredictions.
9:20
W2. Wave effectcorrectionto reciprocitycalibrationresultsof vibration
primary standards. Li-Feng Ge (National Bureau of Standards,
Gaithersburg,
MD 20899andAnhiBureauofStandards
andMetrology,
Hefei, People'sRepublicof China)
Thepaperrevealsthestress
waveeffect(SWE) onreciprocity
calibration resultsof vibrationprimarystandardsandderivesexactcorrectformulasof mechanical
standards
according
to reciprocitytheoryandstress
wavetheory.The paperfurtherexpounds
that boththe electrodynamic
reciprocitymethod (ERM) and the piezoelectric
reciprocitymethod
114thMeeting:
Acoustical
SocietyofAmerica
S50
10:20
(PRM) needthiscorrection
at higherfrequencies
andshows
thattaking
thismeasure
caneliminate
asystem
errorof10-2to10 3ordersofmagnitude.
9:35
W3. Viscoelasticeffectsonsolidamplitudeandphasetransformers.L. M.
B.C. Campos (Instituto Superior Trcnico, 1096 Lisboa Codex,
Portugal)
Thelongitudinal
oscillations
of nonuniformbarsareusedasdisplacementamplifiers
in powertoolsandotherdevices.
Theseoftenoperatenear
resonance[ E. Eisner,J. Acoust.Soc.Am. 35, 1367-1372 (1963) ], sothat
the elasticmodelshouldbe replacedby a viscoelastic
one,whichincludes
damping.In the presentpaper,the longitudinalvibrationsof a tapered
viscoelastic
bar are discussed
generallyfrom the waveequationsfor the
displacement
andstrain.Exactsolutions
areobtainedfor theexponential,
catenoidal,
sinusoidal,
andinverseshapes,
andalsofor theGaussian
and
power-lawshapes.These solutionsgeneralizeearlier resultsfor elastic
bars;e.g.,the elasticGaussianbar [D. A. Bies,J. Acoust.Soc.Am. 34,
1567-1569 (1962)] is generalizedto a viscoelastic
one. Diagramsof
wavenumber
anddampingratio versusfrequencyand viscousrelaxation
time are presentedfor severalshapesof taperedbar; they describethe
propagation
anddissipation
of oscillations
andtheir effectson amplitude
and phase.
9:50
W6.
Vibration analysis of mass-loaded beams. Dhanesh
N. Manikanahally and Malcolm J. Crocker (Department of
MechanicalEngineering,Auburn University,Auburn, AL 36849)
A generalprocedure
fordetermining
thedynamicresponse
of a massloadedfreefreebeamsubjected
to a harmonicandtransientforceisgiven.
Thoughfreefreebeamsare considered
for analysis,the sameprocedure
could be extended for other end conditions also. The beam is assumed to
havestructuraldampingfor determiningthe steady-state
response
due to
harmonicforceexcitation.The modeshapesfor freevibration,dynamic
response,and dynamicstraindue to forcedexcitationare presentedin a
graphical
form.Theanalysis
isusedtostudya spacestructure,
modeledas
a mass-loaded
free free beam,by making an exhaustiveoptimization
searchfor minimumdynamicresponse
due to harmonicand transient
excitationforces.The computerprogramdevelopedfor the analysisis
usedto checksomesimplebeamproblems[G. B. Warburton, The DynarnicalBehaoiourofStructures
(Pergamon,New York, 1976)]. [Work
supportedby SDIO/DNA, ContractNo. DNA-001-85-C-0183.]
10:35
W7. Finite element analysis of a large vibrating space structure.
B. S. Sridharaand MalcolmJ. Crocker (Departmentof Mechanical
Engineering,
AuburnUniversity,Auburn,AL 36849)
Thelargeflexiblespacestructure
to beusedin theStrategic
Defense
InitiativeProjectis modeledas a long flexiblebeamwith threepoint
masses.
UsingtheGalerkinmethod,finiteelementequations
areformulatedthat takeadvantageof thefactthat thenaturalboundaryconditions
comeout as a resultof integrationby parts.Hermite polynomialshave
beenchosen
for theshapeor interpolation
function.A tubularbeammade
ofgraphite
epoxymaterial,100minlengthwith2.0-mo.d.and1.95-mi.d.
W4. Relationship between the impedances and the reflection and
transmission
coefficientsof a junction. L. J. Maga and G. Maidanik
(David TaylorNaval ShipResearchandDevelopmentCenter,Bethesda,
MD 20084)
A junctionconstitutesthe couplingbetweendynamicsystems.In this
case,the one-dimensional
dynamicsystemssocoupledare characterized
by theirwavenumbers
andmassdensities.The interfaceimpedances
of the
dynamicsystems
at thejunctionmay thenbedefined.Thejunctionmay be
definedin termsof ajunctionimpedance
matrix.The natureof thismatrix
will be discussed.
This matrix, togetherwith the interfaceimpedances
of
the dynamicsystems,may thenbe employedto derivethejunction interaction matrix, which consistsof reflection and transmission coefficients.
The manner and results of this derivation will be discussed and a few
is considered
for thepurpose
of thisanalysis.
Massesof 500, 10000, and
1000kgareplacedat theleftextremeend,at a distance
of 20 m fromthe
left extremeend,andat therightextremeendof thebeam,respectively.
Naturalfrequencies
of thelongflexiblebeamarecalculated
usingstandardmethodsandthemodeshapes
arealsoplotted.Resultsarealso
tainedfor a differentlocationand increasedvaluesof the largestmass.
Computercodesare beingpreparedto obtainthe dynamicand steadystateresponse
of thebeamsubjected
to animpulse
anda sinusoidal
force.
10:50
WS. Procedure for the measurement of wavenumber/frequency
admittanceof structures.Karl Grosh, W. Jack Hughes,and Courthey
B. Burroughs(AppliedResearch
Laboratory,The Pennsylvania
State
exampleswill becited.
University,P.O. Box 30, StateCollege,PA 16804)
10:05
WS. Damping and vibration analysisof bondedbeamswith a lap joint.
Mohan D. Rao and Malcolm J. Crocker (Mechanical Engineering
Department,AuburnUniversity,Auburn,AL 36849)
In thispaper,a theoreticalmodelto calculatethe lossfactorsand the
resonancefrequenciesof flexural vibrationsof a systemof two parallel
beamsbondedwith a singlelapjoint by a viscoelastic
materialhasbeen
A procedure
formeasuring
thewavenumber/frequency
admittance
of
structures
usingan arrayof drivesin a standingwavepatternwasdevelopedin a paperpresented
in theASA meetings
in Indianapolis,
IN on 14
May 1987[K. Grosh,J. H. Hughes,andC. B. Burroughs,
I. Acoust.Soc.
Am. Suppl.181, S73(1987)]. In thispaper,dataarepresented
to verify
thevalidityof themeasurement
procedure.
The wavenumber/frequency
spectra
arepresented
forarraysofpointdrivesandthevibration
responses
of lightlydampedbeamsand longbeamswith heavilydampedends.The
effectof steeringthearrayto differentwavenumbers
andvaryingthenumber of drives is examined.
developed.
First,equations
of motionof thejoint regionarederivedusing
a differentialelementapproachconsideringthe transversedisplacements
of the upperand the lowerbeamto bedifferent.The normalforcebetween
eachbeamand the adhesivelayeris represented
by a Pasternakbasemodel, whichconsistsof closelyspacedlinear springs.The shearforceat the
interfaceismodeledusinga viscousmodelfor friction.The resultingequationsof motion,togetherwith equationsof transverse
vibrationsof the
beamsawayfrom thejoint, are solvedusingmotioncontinuityconditions
and boundaryconditionsat the free endsof the beams.Equationsfor
calculatingthe resonancefrequencyand the lossfactor for the caseof
clamped-clampedboundaryconditionsare then derived.Numerical resultsaregenerated
andarecomparedwith experiments
for a systemof two
beamswith a simplelapjoint madeof graphiteepoxycompositematerial.
[Work supported
by NASA-MSFC. ]
S51
J. Acoust.Soc. Am.Suppl.1, Vol.82, Fall 1987
11:05
W9. Influenceof variousparameterson the transmissionof vibrational
power.T. Gilbert,J. M. Cuschieri,M. McCollurn,andJ.L. Rassineux
(Centerfor Acousticsand Vibrations,Departmentof OceanEngineering,
Florida Atlantic University,BocaRaton, FL 33431)
The transmission
of vibrationalpowerbetweentwo thin platesin an Lshapeconfigurationis investigated
usingan SEA model.Only bending
wavesareconsidered
inthemodel.Expressions
aredeveloped
forboththe
ratio of energylevelsin the two platesand the ratio of the transmitted
powerto theinputpower.It isfoundthat theseratiosareonlydependent
uponthreeparameters:
frequency,dampingsof the plates,and coupling
lossfactorsbetweenthe two plates.Therefore,a way to decreaseboththe
114thMeeting:AcousticalSocietyof America
S51
transmitted
powerandtheenergylevelin thereceivingplateovera wide
rangeof frequencies
is to increasethe dampingof the sourceplate.The
couplinglossfactor is influencedby the physicalcharacteristicsof the
plates,suchas area,thickness,and material.The effectof theseparam-
on the response
are analyzed.As a verification,the obtainedresultsare
comparedwith finite elementanalysisand statisticalelementanalysis.
[Work supportedby NASA.]
eterson thecouplinglossfactorandonthepowerandtheenergyratiosis
foundto besmall.Thusthemostefficientwayto controlthe transmission
of powerand the energylevelsis to increasethe dampingof the plates.
This resultis in agreementwith otherresultsobtainedusingthe energy
influencecoefficient
method.[Work supportedby NASA.]
11:35
W11. Experimental measurementof powertransmissionin an L-shaped
beam. M. McCollurn, T. Gilbert, J. Rassineux, and J. Cuschieri
(Departmentof OceanEngineering,
FloridaAtlantic University,Boca
11:20
W10. Power flow method for an L-shai•ed plate. J. L. Rassineux,
J. M. Cuschieri, M. McCollurn, and T. Gilbert (Center for Acoustics
and Vibrations,Departmentof Ocean Engineering,Florida Atlantic
University,BocaRaton, FL 33431)
The powerflow methodis extendedto the analysisof the vibrational
powerflow for two-dimensionalL-shapedplatestructures.The analysisis
for a platethat is assumed
to be simplysupported
alongthe edgesand
pinnedat thejunction.Structuraldampingis introducedby meansof a
complexelasticitymodulus.The transmitted
powerfromoneplateto the
other is computedusinginput and transfergeneralizedmobilities.The
mobilityfunctions
areobtainedfromthesolutionfor theresponse
of a fiat
plateusingeitherpointor edgemomentexcitation.The analyticalsolutionobtainedenables
computation
of theresponse
fora broadband
excitation, regardless
of the rangeof frequencyconsidered.
Differentlocations
of theexcitationpointanddifferentvaluesof dampingandtheirinfluence
S52
d.Acoust.
Soc.Am.Suppl.1,Vol.82,Fall1987
Raton, FL 33431 )
The vibrationalpowertransmittedacrossthejoint betweentwobeams
formingan L-shapedstructure,whenone of the beamsis excitedby a
point forceat the free end, is measuredexperimentally.One methodof
calculatingthe powertransmission
is basedon the assumption
that the
powertransmittedto thereceiverbeamisequalto thepowerdissipated
by
that beam. The dampinglossfactor usedin the calculationis obtained
frommeasurements
onthereceiverbeam.Theresultsof theexperimental
analysis
arecompared
tothoseobtainedusinga powerflowtechnique,
the
resultsof which havebeenverifiedby the closedform solutionfor the
globalstructure.The measurements
showverygoodagreementwith the
analyticalresultsin termsof the locationof the resonantfrequencies,
exceptfor lowfrequencies.
The measured
levelsare,however,significantly lowerthanthe predictedlevels,especially
at theresonantpeaks,indicating that the measureddampinglevelsare underestimated.
The measuredlevelsaregenerallyverycloseto thepredictedlevelsawayfrom the
naturalfrequencies.
[Work supportedby NASA andONR.]
114thMeeting:
Acoustical
Society
ofAmerica
S$2
WEDNESDAY AFTERNOON, 18 NOVEMBER 1987
TUTTLE NORTH ROOM, 12:30TO 1:50P.M.
SessionX. Educationin AcousticsI: Project Laboratoriesfor Undergraduates
Allan D. Pierce, Chairman
Schoolof MechanicalEngineering,
GeorgiaInstituteof Technology,
Atlanta, Georgia30332
Invited Papers
12:30
XI. Developmentof an undergraduate
ex•rimental acousticscenter.Jacek Jarzynski(Schoolof Mechanical
Engineering,GeorgiaInstituteof Technology,Atlanta, GA 30332)
A centerfor experimental
acoustics
andultrasonics
wasrecentlydeveloped
for usein a senior-level
laboratory coursethat is requiredfor the BSME degreeat GeorgiaTech. The centeris a distinctfacility with
permanentlyassigned
instrumentation
andequipmentavailablefor hands-onperformance
of experiments
and
laboratoryprojectsby students;possibleexperimentsare related to current courseofferingsand on-going
researchactivitieswithin theSchoolof MechanicalEngineering.The experimentsthat havebeendevelopedfor
thecenterallowthestudents
to studysomeof thebasicfeaturesof wavemotionandto learnaboutsometypical
applicationsof acoustics.Representative
experimentaltasksthat canbe carriedout within the centerinclude:
measurements
ofpressure
levelsandfrequency
spectraofsoundfromenvironmental
sources;
application
ofthe
ultrasoundto nondestructive
testingof materials;and measurement
of fluid flow usingan ultrasoundDoppler
technique.To the fullestextentpossible,the instrumentation
of the centerhas beenchosensuchthat the
studentswill be introducedto the lateststate-of-the-art
data acquisition,storage,and processing
techniques.
The objectivesof this type of laboratoryinstructionare outlined,with somesamplestudentcomments.The
illustratedtalk will be accompanied
by severallive demonstrations
of the experimentsthat studentscarry out
within the center.
1:10
X2. Project-typeacoustics
experiments
in the USNA acoustics
lab. S.A. Elder (PhysicsDepartment,United
StatesNaval Academy,Annapolis,MD 21402)
For someyears,the Naval AcademyPhysicsDepartmenthasoffereda senior-levelcoursein physical
acoustics,
accompanied
by a weeklylaboratory.Sincethe classes
are small,the laboratoryoffersa chancefor
tutoring the studentsin more advancedand creativeprojectsthan the usual "classic"lab experimentsfor
coursesat this level.Usuallythereis time to performthreeor four projectsoverthe semester,eachonedefined
by a generalareaof interest(suchasenvironmen
tal acoustics,
architecturalacoustics,
computational
anddata
acquisitionmethods,etc.). Sometimesthe projectspillsover into the next semesterand becomesa credit
earningresearch
projectbeyondthecourseitself.Examplesof successful
studentprojectsare:construction
and
testingof a loudspeaker(magneplanar,flamedriven, etc.), acousticalinvestigationof a local concerthall or
church,construction
and testingof an acousticguitar,development
of computer-controlled
data acquisition
and analysissystem.Specificexamples,as well the generalphilosophyof the course,will be given.
1:30
X3. Sonarprojectlaboratoryfor undergraduates.
MurrayS. Korman (DepartmentofPhysics,United States
Naval Academy,Annapolis,MD 21402)
A portablemicrocomputer
workstationfor supporting
basicacousticexperiments
hasbeendeveloped
over
the pastthreeyearsin the PhysicsDepartmentat the U.S.N.A. Studentsenrolledin underwateracousticsand
sonar(a 3-h lecturecoursewithouta laboratory)performfundamentalacoustics
experiments
in theclassroom
withouthavingto utilize largenumbersof analogelectricalboxes.The heartof the workstation(basedon the
6502microprocessor)
includesa low-cost,dual-channel,8-bit analog-to-digital
board.This workstationfeaturesmenuedsoftwarethat can capturea waveformand displayits trace.Simplemathematicaloperations
includesquaringthe waveform,integrating,differentiating,findingthe rms value,and determiningthe probability densityfunction.A 1024-pointFFT programis alsoincludedin the menu.Studentsare not requiredto
know computerlanguagesto operatethe workstationand no experimentis automatedor simulated.During
nonclass
hours,studentsdesignan experimentalprojectthat mightinclude"model"measurements
of target
strength,beampatternfunctions,reflectionloss,soundvelocity,vibration,and studiesof signalsin noise.The
workstations'sversatilitywill be demonstrated.
$S3
J. Acoust.Soc.Am.Suppl.1, Vol,82, Fall1987
114thMeeting:Acoustical
Societyof America
SS3
WEDNESDAY
AFTERNOON,
18 NOVEMBER
1987
UM AUDITORIUM,
12:45 TO 3:30 P.M.
SessionY. S!•eechCommunicationIV: Analysis and Coding
StephenA. Zahorian, Chairman
Departmentof ElectricalEngineering,Old DominionUniversity,Norfolk, Virginia23508
ContributedPapers
12:45
YI. Vector quantizationof LPC imrametersbasedon dynamicalfeatures
ofhearing.ShigeruOnoandTakashiAraseki(NECCorporation,C&C
InformationTechnology
Research
Laboratories,
Kawasaki213,Japan)
Newcode-word
searchcriteriafor vectorquantization
of LPC parametersareproposed.
Variousvectorquantization
schemes
for LPC parametershavebeenproposed
previously.
In theseschemes,
an inputspeech
waveformis partitionedinto successive
shorttime framesand code-word
searchis carriedout underthe criteriabasedon instantaneous
speech
features.Characteristics
of quantizationnoisevary widelyfrom frameto
frame,independent
of thedynamiccharacteristics
of theinputspeech.
At
verylow bit rates,whereit is difficultto keepthequantization
distortion
at a low level,variationin the quantization
noisesignificantly
degrades
the qualityof the reconstructred
speech."Temporalmasking"experimentsindicatethatthereisa postlyecorrelation
beteenthemaskingvalue
andthespeech
spectral
transition
rate.Theseexperiments
alsosuggest
that spectraltransitionratedistortionis emphatically
perceived.
In this
paper,newcriteria,basedon thesetemporalmaskingproperties,
areproposed.Theywouldminimizenotonlytheinstantaneous
spectraldistortion,butalsothespectraltransitionratedistortion.
Usingthesecriteria,
vectorquantizationof the LPC parameters
is developed.
Subjective
experiments
confirmthat thesecriteriaaresuperiorto thosebasedonlyon
instantaneous
speechfeatures.
articulatorytermsare dueto the simplifyingassumptions
underlyingthe
analysis
model.Usually,the assumption
that the systemis all pole [or
anto-regressive
(AR) ] isthoughttobethemostimportantsimplification.
Therefore,it ishopedthattheuseof thelessrestrictivepole-zero[or autoregressive
movingaverage(ARMA)] analysismodelwill offer greater
opportunities
for an artieulatoryinterpretation.A detailedstudyof a
numberof differentARMA analysisimplementations
hasshownthat the
all-poleassumption
may not be the mostimportantrestrictionon the
articulatory
interpretation
oftheanalysis
results;
theassumption
ofGaussianexcitationmayproveto beat leastequallyimpeding.[ Research
supportedby the Foundationfor SpeechTechnology,
fundedby SPIN.]
1:30
Y4. Evaluation ofarticulatory codebooks.$. N. Larar, J. $chroeter,and
M.M. Sondhi(AT&T Bell Laboratories,Murray Hill, NJ 07974)
Thedesignof a codebook
ofarticulatoryshapes
wasrecentlyreported
[M. M. Sondhi,
J.Schroeter,
andJ.N. Larar,J.Acoust.Soc.Am.Suppl.1
81,S78( 1987} ]. Thecodebook
isusedin anautomaticarticulatoryanalysis/synthesis
schemerelyingon goodinitialestimates
of vocaltractcrosssectionalareasto startup an optimizationprocedure[J. Schroeter,J. N.
Larar, and M. M. $ondhi, Proc. IEEE ICASSP, 308-311 (1987)]. An
application-oriented
wayto evaluatethecodebookwouldbeto determine
1:00
Y2. LPC voicing periodicity correction. Paul Milenkovic and
SotaroSekimoto(WaismanCenter,Universityof Wisconsin-Madison,
1500HighlandAvenue,Madison,WI 53705-2280)
Theautocorrelation
method
oflinearpredictive
coding
(LPC)analysismatches
thefirstp samples
of theautocorrelation
functionof theim-
pulse
response
ofanall-pole
filtertotheautocorrelation
function
comput-
howmuchthe final optimizedshapedeviatesfrom the shapeinitially
selected.
A moregeneralevaluationis to computetheaveragedistortion
incurredin quantizingsomeinputrecordof speech.
Usingthisprocedure
withanappropriatedistancemeasure,variousaspects
ofeodebookformation areevaluated.In particular,the focusis on the strategies
utilizedfor
generatingtrainingdata. Also consideredis the effectof differentapproachesto code-wordformationoncethe trainingdata havebeenobtained. Evaluation results for this work done to refine the codebook will be
presented
alongwith the performance
asa functionof codebooksize.
edfroma speech
waveform.
Thea•tocorrelation
function
ofthespeech
waveform
isinfluenced
bytheperiodicity
ofthevoice
source,
aswellasby
thewaveform
window.Thisinfluence,
whenincorporated
intotheautocorrelation
functionof theall-polefilter,resultsin errorsin formantfrequencyandbandwidthvaluesthatbecomeimportantat thefundamental
i
1:45
YS. Speakeradaptationin articulatoryspeechanalysisby synthesis.
frequencies
typicalof femalespeech.
Theuseofananalysis-by-synthesis J. Schroeter,J. N. Larar, andM. M. Sondhi(AT&T Bell Laboratories,
technique
isproposed,
wheretheautocorrelation
function
oftheoutput
waveform
ofanLPCsynthesizer
ismatched
tothespeech
dataautocorrelationfunction.
Theall-pole
filterdetermined
byLPCanalysis
provides
a
matchwhenthesynthesizer
isoperated
at anextremely
lowfundamental
frequency.
Thesynthesizer
fundamental
frequency
is increased
in small
steps
andcorrections
aremadetotheall-pole
filterateachsteptopreserve
theautocorrelation
functionmatch.Thisprocess
continues
untilthecor-
rectvalueofthefundamental
frequency
isreached.
[Worksupported
by
NIH Grant NS 21516-3.]
speech analysis as a means for studying articulation.
Louis Bores and Johan de Veth (Institute of Phonetics,Nijmegen
University,P.O. Box9103, 6500HD Nijmegen,The Netherlands)
It is well documented
that linearpredictionanalysiswill only allow
prediction
coefficients
to relateto vocaltractshapes
underveryspecial
conditions,
and that the problemsin interpretingLP analysisresultsin
S$4
Usingan articulatoryapproachfor low-bitrate speechcoding[J.
Schroeter,
J. Larar,andM. M. Sondhi,J. Acoust.Soc.Am. Suppl.1 80,
S19 (1986); Proc.IEEE ICASSP 308-311 ( 1987) ], meansfor adapting
ananalysis/synthesis
scheme
todifferentspeakers
wasinvestigated.
Since
a crucialfeaturefor thisapproachto speechcodingis the useof an articulatory codebookof tract shapesand relatedtransferfunctions[M. M.
Sondhi,
J.Schroeter,
andJ.N. Larar,J.Acoust.Soc.Am.Suppl.181,S78
( 1987); J. N. Larar, J. Schroeter,and M. M. Sondhi, J. Acoust. Soc. Am.
1:15
Y3. ARMA
Murray Hill, NJ 07974)
J. Acoust.Soc. Am. Suppl.1, Vol. 82, Fall 1987
Suppl. I 82, S54 (1987)], the codebookentrieshave to be modifiedto
accommodate
differentnominalvocal-tractsizes.Two differentwaysof
speakeradaptationare compared.In the first approach,the codebookis
comprisedof severalsubcodebooks,
eachfor a differentsizeof the vocal
tract.In thiscase,a methodfor determiningtheoptimalsubcodebook
for
eachspeakeris needed.Alternatively,in the secondapproach,the LPCrepresentation
of the originalspeechis scaledfor accessto a constant
tract-sizecodebook.Then, the codebookentry foundis inverselyscaled
for synthesis.
Here,a methodfor determining
theoptimalscalefactoris
required.
114th Meeting:AcousticalSocietyof America
S54
2:OO
Y6. Speechformanttrajectoryestimationusingdynamicprogramming
with modulated transition costs. David Talkin (AT&T Bell
Laboratories,
Room2D-410, 600 MountainAvenue,Murray Hill, NJ
07974)
A newalgorithmto trackautomatically
speech
formantfrequencies
havebeendeveloped.
Dynamicprogramming
isusedtooptimizeformant
trajectory
estimates
by imposing
appropriate
frequency
continuity
constraints.The continuityconstraints
aremodulated
by a stationarity
function.The formantfrequencies
areselected
fromcandidates
proposed
by
solving
fortherootsofthelinearpredictor
polynomial
computed
periodicallyfromthespeech
waveform.The localcostsof all possible
mappings
of thecomplexrootsto formantfrequencies
arecomputed
at eachframe
basedon thefrequencies
andbandwidths
of thecomponent
formantsfor
eachmapping.Thecostofconnecting
eachof thesemappings
witheachof
themappings
in the previous
frameis thenminimizedusinga modified
Viterbialgorithm.Two sentences
spokenby 88 malesand43 femaleswere
analyzed.The first three formantswere trackedcorrectlyin all sonorant
regionsin over80% of thesentences.
Theseperformance
resultsarebased
onspectrographic
analysis
andinformallisteningto formant-synthesized
speech.
2:15
Y7. Somepropertiesof autoregressive
modelrelatedcepstrum.BiingHwang Juang and David Mansour (AT&T Bell Laboratories,600
Mountain Avenue,Murry Hill, NJ 07974)
Autoregressive
modelrelatedcepstrum,or, briefly, LPC cepstrum,
recentlygainedrenewedattentionbecause
it wasshownto bean effective
representation
in speechrecognizerdesigns[B. H. Juang,J. G. Wilpon,
and L. R. Rabiner, Proc. IEEE ICASSP-86, 765-768 ( 1986); B. Hanson
and H. Wakita, Proc. IEEE ICASSP-86, 757-760 (1986); Y. Tohkura,
Proc. IEEE, ICASSP-86, 761-764 (1986) ]. In this paper,someproper-
tiesoftheLPC cepstrum
areinvestigated
thatareof importantconsideration whenthe recognizeris to be deployedin situationswheremismatch
betweenthe trainingconditionsand the testingconditionsmay potentially occur.More specifically,
the effectsof LPC analysisorder, additive
noise,and pole movementsupon somekey characteristicsof the LPC
cepstrumareconsidered,
suchastheaverageandthe normof thecepstral
vector.A simplerelationshipamongthe cepstralcoefficients,
the predictor coefficients,and the reflection coefficientsis established,and unlike
the Itakura-Saitodistortions,it is shownthat the L 2 distortionbetween
twocepstraobtainedfromdifferent-order
LPC modelsof thesamespeech
data may containan inherentnonzerobias.Also consideredare the effects
of additive noise,usingan additive power spectrummodel and a constrainedARMA model (sum of an all-polemodeland a constant).It is
shownthat the norm of the LPC-cepstralvectorshrinksas a resultsof
noisecontamination,comparedto that of the cleanspeech.Further, moving the polesof an LPC-modelspectrumis shownto be equivalentto
multiplyinga powerseriesto the cepstrumand thusLPC-modelbandwidth broadeningand poleenhancement
can be easilyaccomplished
in
bridgingtheencryptedsignalsin a singleB-voicechannel)isdiscussed.
In
particular,an enhancement
procedureusinga prefilter,"dither" noise
andan adaptivepostfilteris proposed.
The systemis basedon an all-pole
modelfor thedegraded
speech.
Thecoefficients
of thepostfilterareeasily
derivablefromtheall-polefilterparameters.
Informallisteningtestshave
shownthat theenhanced
speech
isnear"toll" quality.
2:45
Y9. Invariant acousticcuesin stop consonants:A cross-languagestudy
usingthe Wignet distribution.H. Garudadri (Electrical Engineering,
University of British Columbia, Vancouver,British ColumbiaV6T 1W5,
Canada), J. H. V. Gilbert, A-P. Benguerel(Audiology and Speech
Sciences,Universityof British Columbia,Vancouver,British Columbia
V6T IW5, Canada), and M.P. Beddoes (Electrical Engineering,
Universityof BritishColumbia,Vancouver,BritishColumbiaV6T 1W5,
Canada)
Acousticinvariancewasinvestigated
in 200 uoaspiratedstopsfrom
English,Telugu,andFrench,usingtheWignerdistribution.
Thebilabials
were characterizedeither by absenceof any noticeableburst,or by an
energyconcentration
in thelow-frequency
regionduringtheburst,when
present.The burstof alveolarswas mostlydiffusein nature,but sometimesbecamecompact,especially
whenit wasfollowedby a backvowel.
Theburstofvelarshada compactspectrum
centered
nearF2ofthevowel,
whenfollowedbybackvowels,
butwasmostoftendiffusewhenfollowed
by a front vowel.The burstof all dentalfrom Teluguwasfoundto be
diffuse.Whentheburstof alveolarswascompact,or thatof velarsdiffuse,
the durationfrom the startof the burstto the startof the voweland F2 of
the vowelwerefoundto be reliablecuesfor placeof articulation.The
diffusenatureof bilabialsand alveolars,reportedby Lahiri et al. [J.
Acoust.Soc.Am. 76, 391-404 (1984) ] and by the authorsreferenced
therein,canbe partlyattributedto the temporalaveraging
of the burst
spectrum
andthediffusevowelspectrum,
whichisinevitable
in Fouriertypeanalyses[Garudadriet al., J. Acoust.Soc.Am. Suppl.I 79, S94
(1986) ]. Unlike in otherinvestigations,
no apparentpatterncouldbe
foundfor the tokenswronglyclassified.[Work supported,in part, by
NSERC, Canada. ]
3:00
Y10. A new mathematical model for intonation: Historical
motivation
and application. Deborah Rekart (Department of Speech
Communication,The PennsylvaniaState University, University Park,
PA 16802), and David Drumright (Department of Mechanical
Engineering,The PennsylvaniaStateUniversity,UniversityPark, PA
16802)
Early attemptsto characterizeEnglishintonationwere theoretical
descriptions
in termsof tones,tunes,andsegmental
pitchlevels.Recent
acousticdescriptions
of intonationhaveinvolvedthe perceptualdeterminationof F0 contoursin termsof globaldeclinationlinesor asbreath
the cepstraldomain. Consequently,
evaluationof some frequency-
groupswith terminaland nonterminalslopes.Liebermanet al. (1985)
weighteddistortionmeasuresthat are believedto be desirableundercertain conditionsbecomes
straightforward
via cepstralprocessing.
showedthat F0 contourscouldbedescribedobjectivelyby all-pointslinear regression
lines,but thisdid not yielda compactcharacterization
of
the contours.Hirst (1983) developed
a modelbasedon nonlinear(parabolic) function,but it is not unifiedin that it resetsparametersfor syllablesindependently.
Attemptsto compareintonationcontoursin different
languagesand dialectshavebeenbasedon the existingmodels.In the
followingabstracta mathematicalmodelcapableof compactlyquantifying intonationcontoursusingfour parameters
is proposed[Drumright
and Rekart (1987)]. This paper demonstrates
how the modelcan be
appliedto analyzeforeignlanguage,
non-native,
anddialectaldifferences
in the intonationof statementsand questionsin spontaneous
and read
speech.
2:30
Y8. Speech enhancement in crypto-bridge communication systems.
Daniel Lin and Yacov Yacobi (Bell Communications Research, 435
South Street, Morristown, NJ 07960)
In secureaudioteleconferencing,
a crypto-bridgesystemsynchronouslyaddssimultaneous
encryptedsignals,moduloa knownnumberP,
andbroadcasts
theresultto theparticipants.
Eachterminal,usinga secret
key, then decryptsthe modular sum of encryptedsignalsto obtain the
desiredordinary sum of plain text signals.Suchsecrecysystemsare prov-
ablysecure,assuming
the existence
of one-wayfunctions(e.g.,DES) for
the modularsum cipher [E. F. Brickell et al., CRYPTO-87]. In this
paper,the implementation
of additivecryprosystemsin a narrow-band
(2B + D) ISDN environmentare considered.The problemof noisereduction for 6-bit linear PCM speechcoding (an essentialconstraintfor
$55
d.Acoust.
Soc.Am.Suppl.
1,Vol.82,Fall1987
3:15
Yll. A new mathematical model for speech intonation: Theory and
hardware/softwarerealization. David G. Drumright (Department of
Mechanical Engineering,The PennsylvaniaState University, University
114thMeeting:
Acoustical
Society
ofAmerica
S55
rationis controlledby four overallparameters.
The modelhasbeenrealizedandtestedin softwareformby a programthat readsan actualintonation curve [producedby the programPIG and describedin J. Acoust.
Soc.Am. Suppl. 1 gl, S78 (1987)] and setsthe four parametersby an
iterativematchingprocess.The hardwarerealization,by a circuit involving coupledoscillators,invitescomparisonwith analogous
neuralstruc-
Park, PA 16802), and DeborahM. Rekart (Departmentof Speech
Communication,The PennsylvaniaState University,UniversityPark,
PA 16802)
A mathematicalmodelbasedoncombinations
of sinusolds
andexponentialdecayis shownto be superiorin representing
actualintonation
contours.The modelis generative
ratherthanad hoc,in that theconfigu-
WEDNESDAY
AFTERNOON,
18 NOVEMBER
tures.
1987
TUTTLE
CENTER
ROOM,
1:00 TO 2:50 P.M.
SessionZ. Physical AcousticsIV: Recent Advancesin Fiber Optic Sensors
David L. Gardner, Chairman
NationalOceanic
andAtmospheric
Administration,
CodeN/CGx3,Rockville,
Maryland20852
Chairman's
Introduction--l:0fi
Invited Papers
1:05
Zl. Acousticsensordevelopmentat NRL. A. Dandridge (Code 6574, Naval ResearchLaboratory,
Washington,DC 20375)
The development
of fiberopticacousticsensors
at the Naval ResearchLaboratorywill be reviewed.The
talkwilldescribe
thefundamentals
ofthedesign
andoperation
offiberopticsensors.
Themajorareaofthistalk
willbethetransduction
mechanism
ofacoustic
energy
toopticalphase
shift.Methods
todetectthephase
shifts
andtoprovide
a linearvoltage
outputwillonlybebrieflydiscussed.
Thefrequency
regimes
tobecovered
range
from a few tensof Hz to MHz. In the low-frequency
regime(up to severalkHz), wherethe pressureis
hydrostatic,theroleof thematerialraGdullof fibercoatingsandbulkmandrelswill beconsidered.
A numberof
sensor
designs
for operation
in thehigher-frequency
regimes,
whereinertialeffects
do notpermitdirectaxial
straintermsto play a major role, will alsobe described.
1:35
Z2. Multiplexingtechniques
for interferometriefiber-opticsensors.A.D. Kerseyand A. Dandrige(Code
6574, Naval ResearchLaboratory,Washington,DC 20375)
Considerable
research
interestispresently
beingdirectedtowardthedevelopment
of all-fiber,multisensor
networksfor usein arraysandapplications
wherea largenumberof differentphysicalparameters
are of
interest,
suchasthoseencountered
intheindustrial
process
controlarea.A numberof"all-optical"approaches
to themultiplexing
of suchnetworkshavebeenproposed
in recentyears.Thesetechniques
aremostattractive
for usein a wide rangeof applicationareas,asthe sensorsoperatepassivelyand can be remotely locatedfrom
thesourceanddetectionelectronics.
Furthermore,theoverallsystemcomprising
the sensors
andfiberlinks
retainsa low susceptibility
to electromagnetic
interference.
The principleof operationof multiplexingtechniques
basedontime,frequency,
andcoherence-division
addressing
schemes
will bedescribed.
Thepaperwill
compareexperimentally
reportedperformance
featuressuchasthe multiplexingefficiency,sensitivity,crosstalk, etc.,and will discuss
practicallimitationsof the variousmethods.
2:05
Z3. Thermalfioiselimitationsin u fiberopticselsmiesensor.S. L. Garrett,T. Hofler(PhysicsDepartment,
Code 61 Gx, Naval PostgraduateSchool,Monterey,CA 93943), and D. L. Gardner (National Oceanicand
AtmosphericAdministration, Code N/COx3, Rockville, MD 20852)
Opticalfibersareneithersensitive
norselective
asa transduction
medium.The highsensitivityof mostfiber
opticsensors
hasbeena consequence
of thefactthatopticalinterferometric
demodulation
iscapableof resolv-
ingphase
changes
oforder1/zrad/x/-•.In afibersensor
of10-mlength,
thisisequivalent
toaresolution
ofone
partin 10TM
during
a 1-sobservation
using
lightof900-nm
vacuum
wavelength.
Forcomparison,
agoodquality
l-in. condenser
microphone
canresolvea relativechangein diaphram-to-backplate
separation
of onepart in
108duringa l-sobservation.
Thisdetection
advantage
of 120dBhasobscured
many"sins"inseveral
fiberoptic
sen,sor
designs.This presentation
will concentrateon the sensitivitylimitationsimposedby the fluctuation-
S56
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
114thMeeting:Acoustical
Societyof America
S56
dissipation
theorem
[L. D. Landau
andE. M. Lifshitz,
Statistical
Physics
(Addison-Wesley,
Reading,
MA,
1969),2rided.,ChapXII ] at nonzerotemperatures
andwill demonstrate
that the thermallimitationsare
entirely
analogous
tofluctuations
observed
in "mirrored
galvanometers"
thatalsouse"optical
leverage"
to
increase
sensitivity.
Theresults
willbeapplied
totheperformance
ofa seismic
sensor
witha sensitivity
thatis
limitedbyitsintrinsic
thermalnoise.[Worksupported
bytheOfficeof NavalTechnology
andtheOfficeof
Naval Research.]
ContributedPaper
2:35
ZA. A compactfiber optic laser probe to monitor surface vibration
displacements.
Jacek Jarzynski,Dewon Lee, and Yves H. Berthelot
(Schoolof MechanicalEngineering,
GeorgiaInstituteof Technology,
Atlanta, GA 30332)
An heterodyne
laserinterferometer
isusedtomonitorthephasemodulationofthelaserlightscattered
froma vibratingsurface.
A laserbeamis
splitintotwoarmsof an interferometer
wherelightis guidedthrough
singlemodeopticalfiberssoasto preserve
phaseinformation.
Therefer-
WEDNESDAY AFTERNOON, 18 NOVEMBER 1987
enceand frequency-shifted
signalsare recombinedin a multimodefiber
tightlyconnected
to a receivingphotomultiplier.
Miniaturegradientrefractiveindex (GRIN) lensesare usedto providemaximumefficiency
andto maketheprobeascompactaspossible.
Bothnormalandtangential
components
of thesurfacedisplacement
canbedetermined
witha probe
illuminatingthe vibratingsurfaceat normalincidenceand at two mutually perpendicular
off-normaldirections.The tangentialcomponentof the
surfacedisplacement
is foundfromspecklereflection
of thenonperfectly
flat vibratingsurface.This compactprobecanbe positioned
at somedistance( 10-50 cm) from the vibratingsurfacefor truly nonintrusive
measurements.
PREFUNCTION AREA, 1:00TO 3:00 P.M.
SessionAA. Psychological
and PhysiologicalAcousticsIV (PosterSession)
Craig Formby, Chairman
Departmentof Communicative
Disorders/Neurology,
J. H. Miller Health Center,Universityof Florida,Box J-174,
Gainesville, Florida 32610
ContributedPapers
All posters
will bedisplayed
from 1:013
to 3:00p.m.To allowcontributors
theopportunityto seeotherposters,
contributors
of odd-numbered
paperswill beat theirposters
from 1:00to 2:00p.m.andcontributors
of evennumberedpaperswill beat theirpostersfrom 2:00to 3:00p.m.
AA1. Diseriminability,loudness,and maskingin the rat: A confirmation
and extension. Thomas G. Raslear (Department of Medical
Neurosciences,
Walter Reed Army Instituteof Research,Washington,
DC 20307-5100)
Rats discriminatedbetweentwo sound-pressure
levels(SPL) of a
puretone:standard(STD) SPLsof 84 and74 dB, andcomparison(CO)
SPLs4, 14,and24dBbelowSTD weretestedin quietand60-dBnoiseat 4
and 12.5 kHz (24 c0nditions). The decibel differencebetween STD and
CO accountedfor only 43.52% of the variancein the signaldetection
measureof sensitivity(d') acrossconditions,whereasthe loudnessdiffer-
ence(LD = STDø3• - COø'3s) accounted
for 89.82% ofthe variancein
d '. Theseresults
confirmandextendprevious
observations
that:( 1) equal
decibeldifferences
arenot equallydiscriminable
[R. Piertel,J. G. Sherman,S.Blue,andF. Hegge,J. Exp. Anal. Behav.13, 17-35 (1970) ]; (2)
loudness
for therat increases
asa powerfunctionof SPL, with an expo-
nentof0.35 JR.Pierrel-Sorrentino
andT. G. Raslear,
J.Comp.Physiol.
Psychol.94, 757-766 (1980) ]; ( 3 ) maskedloudnessisa linearfunctionof
loudness
in quiet [T. G. Raslear,R. Pierrel-Sorrentino,
and F. Rudnick,
Behar. Neurosci. 97, 392-398 (1983) ].
L. Brill (Chicago ZoologicalSociety,BrookfieldZoo, Brookfield,IL
60513andParrelyHearingInstitute,LoyolaUniversityof Chicago,6525
N. SheridanRoad, Chicago,IL 60626), Martha L. Sevenich,Timothy
J. Sullivan,JanetD. Sustman,andRonaldE. Witt (ChicagoZoological
Society,BrookfieldZoo, Brookfield,IL 60513)
A dolphin (Tursiopstruncatus)was conditionedto performa discriminationtask,by meansof echolocation,
in a "Go/No-go" paradigm
whilestationedin an underwaterhoopand wearingsuctioncupsoverits
eyes.To investigatethe hypothesisthat the fat-filledlowerjaw of odontocetecetaceansprovidesan acousticalpathwayto the inner ear, the dolphinwasadditionally
requiredto performthetaskwhilewearingeitherof
two rubberhoodsdesigned
to coverits lowerjaw. Onehood,constructed
from nonfoamedneoprene,allowedreturningacousticsignalsto pass,
whiletheotherhood,constructed
fromclosed-cell
neoprene,substantially attenuatedsuchsignals.The dolphin'sperformance
wassignificantly
hindered
whilewearing
theattenuating
hood(p < 0.001,X 2) asopposed
to its wearingthe hoodmadeof nonfoamedneopreneor no hoodat all.
Acousticaldata tape recordedduring the experimentindicatethat, with
few exceptions,
the spectralpeaksof the dolphin'soutgoingecholocation
signalsaveragedbetween30 and 50 kHz. Theseresultssupportthe hypothesisand agreewith previouselectrophysiological
data that suggest
AA2. Evidence for an acoustical pathway to the inner ear through the
that thelowerjaw is involvedin the transmission
of high-frequency
sig-
lower jaw for an echolocatingdolphin(Tursiopstruncatus).Randall
nals to the inner ear.
S57
d.Acoust.Sec.Am.Suppl.1, Vol.82, Fall1987
114thMeeting:Acoustical
Societyof America
S57
AA3. Modulationand gap detectionwith filtered and broadbandnoise
signals.C. Formby (Departmentsof CommunicativeDisordersand
pieallylimitedextentsat differentrates.Results
appearconsistent
with
augmentinginfieldinhibition.
Neurology,Universityof Florida,Gainesville,FL 32610), K. Muir,
J. Uranga,C. Lynn,andA. Ahlers(Departmentof Speech,
University
of Florida, Gainesville, FL 32610)
The higheraudiometric
frequencies
arguablyarethemostimportant
for sometasksrequiringfinetemporaldiscriminations.
Bothmodulation
andgapdetection
thresholds
improve
withincreasing
centerfrequency
of
noisebands.For modulationdetection,however,not all investigators
are
convinced
that improvedperformance
isnecessarily
dependent
on sensitivity at the highercenterfrequencies.
They pointout that the high-fre-
AA6. The effectsof pedestallevel on incrementalauditory responses
in
humans: Loudness matching study. Hiroshi Riquimaroux and
Peter Dallos (Auditory Physiology Laboratory, Northwestern
University,2299SheridanRoad,Evanston,IL 60201)
The effectsof pedestallevel (L B) on incrementalauditoryresponses
wereinvestigated
in normal-hearing
humansubjects
withamplitudemod-
quency
advantage
formodulation
detection
maybea consequence
ofcon-
ulated (AM) white noise by meansof a loudnessmatching procedure.
comitantincreasesin stimulusbandwidthas a functionof increasing
centerfrequency
of thenoiseband.To determine
whethersignalfrequen-
The methodof adjustmentwasusedto findequallyloudincrements(AL)
for variousstandardsALs andL Bs ( 30-80 dB SPL). The L B for standard
cyor signalbandwidth
ismoreimportantfor modulation
andgapdetection, modulationand gapdetectionthresholds
weremeasuredfor lowpass (LP) filterednoise (fc--4000 Hz, bandwidth=4000Hz),
high-pass
(HP) filterednoise(fc = 4000Hz, bandwidth
= 2500Hz),
loudness
of AL isindependent
ofL B.The resultsshowthatloudness
of •L
and broadband(BB) noise (bandwidth= 6500 Hz). Modulation and
gapdetection
thresholds
fortheBBandHP signals
weresimilar,andwere
betterthan thresholdsfor the LP signal.The ability to hear the higher
frequencies
of the noisesignalapparentlyis moreimportantfor these
tasksthan is perceptionof signalbandwidth.[Researchsupportedby
Divisionof Sponsored
Research,Universityof Florida,and American
•L waskeptconstant
at 30dBSPL.Thehypothesis
tobetestedwasthat
appears
to bealmostindependent
ofL• for verysmallAL ( < 6 dB). The
findingsalsoindicatethe possibilitythat the stimuluspeaklevel (Lv)
mightbe involvedin the determination
of loudness
of AL whenAL is
large.The datademonstrate
that the slopeof loudness
growthfunction
increases
asL B increases.
For lowL Bs,theslopehasa tendencyto asymptote to the referenceline with the slopeof one. The resultsagreewith
earlierJND data. It is concludedthat the hypothesisappearsto be supportedby the presentdata for verysmallALs.
Cancer Society.]
AA4. Effect of click rate and delay on breakdown of the precedence
effect. Rachel K. Clifton (Department of Psychology,University of
Massachusetts,Amherst, MA 01003) and Richard L. Freyman
(DepartmentofCommunication
Disorders,Universityof Massachusetts,
Amherst, MA 01003)
When clicksare presentedfrom two loudspeakers,
with one output
leadingthe otherby a few ms,a listenerlocalizesthe soundsolelyat the
leadingloudspeaker,a phenomenonknown as the precedenceeffect.
However,the precedence
effectcanbe disruptedfor severalsecondsif the
leadingand lagging(echo) locationsare quickly switched[Clifton, unpublishedmanuscript].Click trainswerepresented
from two loudspeakers, placed90øright and left off midlinein an anechoicchamber,with
laggingclickdelaysrangingfrom2-9 ms.Clickrateswere1,2, 4, 6, and8/
s. Under someconditions,subjectsreported hearing clicks from both
loudspeakersimmediatelyfollowing the switch in leading and lagging
outputs,indicatinga breakdownof the precedence
effect.The lengthof
timebothclickswereheardfollowingthe switchwasaffectedby bothecho
delay and click rate. Inhibition of the precedenceeffectwas strongest
whenrate of clickswasslowerand delayswerelonger,that is,just under
the subject'sechothreshold.At shorterdelaysand fasterratesthe precedenceeffectwasexperienced
throughoutthe trial.
AA7. The effectsof pedestallevel on incrementalauditory responsesin
humans:Brainstemresponse(ABR) study.Hiroshi Riquimarouxand
Peter Dallos (Auditory Physiology Laboratory, Northwestern
University,2299 SheridanRoad,Evanston,IL 60201)
The effectsof pedestal
level(L•) on incremental
auditoryresponses
wereexaminedin normalhearinghumanadultswith amplitudemodula-
ted (AM) whitenoiseby usingtheauditorybrainstemresponse
(ABR).
The waveV latencyof ABR, yieldedby a noiseincrement(AL) with
various
Lss ( 30-80dBSPL), wasmeasured.
Thehypothesis
ofthisstudy
is that the waveV latencyderivedby AL is invariantwith L B. The results
showthatthewaveV latencyappearsto bealmostindependent
of L• for
verysmallAL ( <6 dB). Thedataarecompared
withthoseofthecompanionloudness
matchingstudy.Similartendencies
areseenin tbecharacteristicsof iso-waveV latencycontoursand equalloudnesscontoursfor
relativelysmallALsor for lowLss. The growthfunctionsobtainedfrom
the two experiments,
however,are different.In the loudness
matching
studythe slopeof loudness
growthfunctionsincreases
asLs increases,
whilein the ABR studythe slopeof growthfunctionsof waveV latency
increasesonly for low L s.
AAS. Testing children and the aged with computerized audiomerry.
AAS. Inhibitory mechanismsand cortical processing.D. M. Daly, D.
D. Daly (Box 210855, Dallas, TX 75211), J. W. Drane (Auburn
University,Auburn, AL 36849), and J. A. Wada (University of British
Colombia, Vancouver, British Columbia V6T 1W5, Canada)
When balanceof inhibitionsdeclines/fails,patientswith seizuresin
auditory cortex report certain synthetic [be]-[de]-[gc] as nasals,
"bleats,"and then undifferentiatedbuzzes.Effectsof increasedinhibition
canappearwithauditorycortexin volumesurrounding
disinhibited
areas
(evencontralaterally):Patientsreportsamerangeof stimulias clearly
identical[J. Neurophysiol.44, 200-222 (1980)]. Here a casewith seizuresin visualcortexand post-ictallyimpairedauditorycomprehension
(but normalperipheralacuity),isreported.Testingincludedprerecorded
setsof [be]-[de]-[gc], [ge]-[ye], and [be]-[we] presentedthrough
headphones
monaurallyandbinaurally.Duringepisodes
with morefrequentseizures,patienthad intervals(somelastingnearlyan hour) when
[de] boundariesfor [be]-[de] and [de]-[ge] increasedapproximately
200 Hz; [be]-[wc] and [gc]-[ye] boundaries
increased
40-50 ms (with
stimulilessthan 50 msnowreportedasvocalic).The BDG stimulicover
tonotopicallydifferingextentsof cortex;BW or GY stimulicovertonoto-
S58
J. Acoust.
Soc.Am.Suppl.1, Vol.82, Fall1987
Michel Pieard (University of Montreal, Montreal, QuebecH3C 3J7,
Canada), Henry J. Ilecki, and Sames D. Baxter (Royal Victoria
Hospital/McGill University,Montreal,QuebecH3A 1A1, Canada)
Usingcomputerized
audiometryin a groupof noise-exposed
workers
has beenshownto be a reliableand valid meansof assessing
hearing
sensitivity[ M. Picardetal., Proceedings:
Computer
/lpplications
to Canadian Health, pp. 127-130 (1987) ]. Basedon this study,an investigation
wasconducted
to similarlydeterminethefeasibilityof implementing
likemethodology
in twoclinicalpopulations
typicallyregardedas"difficultto
test" (viz., geriatricand pediatricgroups).Childrenwereaged8 to 12;
seniors,65-81 years.Reliability was assessed
by relatingair- and boneconductionthresholds
wheretherewasno evidenceof middle-earpathology. Validity was measuredby comparingair-conductionpure-tone
thresholds(0.5, 1, 2, 3, 4, and 6 kHz) obtained under two test modalities,
computerizedaudiometry and conventionaltesting performedby a
trainedexaminer.Bothprocedures
followedANSI S3.21-1978.Findings
in both agegroupswerecomparableto thosereportedin the previous
study.Coefficients
of reliabilityremainedequallyhighacrossfrequencies
regardless
of testingmethod.As well,highcorrelations
betweenconventional and computerized
audiometrywerefound.Complementing
this
114thMeeting:
Acoustical
SocietyofAmerica
S58
observation,
a PCAsupported
thecriterion-related
validity
ofcomputerizedaudiomerry.
[Worksupported
by MRC. ]
AA9. Frequency
specificity
of theeochlearactionpotentialvarieswith
stimulus presentation rate. Alex N. Salt, Arti
R. Vora, and
Ruediger
Thalmann(Department
of Otolaryngology,
Washington
demonstrate
the presence
in the OC of specific
subtypes
of certainproteins.In thecaseofcontraction
associated
proteins,
forinstance,
thepresenceof nonmuscle
actin (betaand gamma),threetypesof nonmuscle
tropomyosin
(Tm:4,Tin:5,andTin:8) andnonmuscle
lacticdehydrogenase(LDH B) wasdocumented.
Anotherimportantroleof 2D-PAGE is
thedemonstration
of previously
unknownproteins.
The presence
in the
OCoftwohighlyprominent
proteins
oflowmolecular
weightandstrongly acidicpH(assumed
to bespecific
to theOC) wasshown.Accordingly,
theyweretermedOCP-I andOCP-II [I. Thaimannetal., Arch. Otorhin-
University,SaintLouis,MO 63110)
olaryngol.226, 123-128 (1980)]. It was found that small amountsof
It iswelldocumented
thattheamplitude
of anaveraged
cochlcar
actionpotentialdecreases
astherateof stimulus
presentation
isincreased.
In thepresent
study,frequency
regions
contributing
totheAPelicited
by
toneburststimuliat ratesfrom4 to80/shavebeeninvestigated
in guinea
pigsusing
a tonemasking
procedure.
Derived
responses
corresponding
to
specific
regions
wereobtained
by subtracting
AP responses
in thepres-
OCP-I andOCP-II arepresentin spiralligamentandspirallimbusand
moresubstantial
amountsin basilarmembrane.
Neitherproteinisdetectablein striavascularis.
Likewise,noproteinsresembling
OCP-I or OCP-
enceof a low-levelcontinuous
maskingtonefromthosein theabsence
of
masker.Thisisa modification
of thetechnique
described
by Hoodet al.
[J. Acoust.Soc.Am. Suppl.1 81, S8 (1987)]. Whenstimulationrateis
II were found in tissues other than inner ear. While some biochemical
featuresof the two proteinshave in the meantimebeencharacterized,
their functionalsignificance
remainsobscure.[Work supportedby
NIH. 1
increased,
thederived
response
amplitudes
decreased
neartheprobefrequencyregion,whileamplitudes
at outlyingfrequencies
werelessmarkedlychanged.
Thesedatasuggest
thecontribution
to theAP fromthe
region
corresponding
totheprobefrequency
becomes
lessathighstimula-
tionrates.Withan80/sstimulation
ratethecontribution
fromthisregion
isnegligible.
Thedegradation
offrequency
specificity
ofresponses
ispre-
AAll. Ultrastructural correlatesof hair cell motility. B. N. Evans and
A. Yonovitz (GraduateSchoolof BiomedicalSciences,
The University
of Texas Health ScienceCenter at Houston, Houston,TX 77030)
sumedto arisefromeachstimulusactingasa "forwardmasker"for the
following
stimulus.
To optimize
thefrequency
specificity
ofAP responses
Nonstimulatedas well as outer hair cellsshowingmechanicaldis-
to toneburststimuli,the rate of presentation
mustthereforebe considered. [Work supportedby NIH.]
placementsto electricaland chemicalstimulationwere examinedultrastrueturally to assessthe lability of a rhodamine-labclcdactin structure
AA10. Proteins of the organ of Corti (OC}. IsoldeThalmann,
GertraudThailinger, and RuedigerThaimann (Department of
Otolaryngology,
Washington
University,SaintLouis,MO 63110)
extendingbetweenthe cuticularplateand the peri-nuclearregion.Hair
cellsof varyinglengths(20-80 pro) werestimulatedand immediately
fixedfollowingmechanical
displacement.
All cellsrevealeda distinctnonmembraneboundcomplexin crosssection,but were infrequentlyobservedin longitudinalsections.The cross-sectional
area of the structure
increased
in successive
ascending
sections.
This structurespiralsapieally
in a nondirectmanner,buteventuallyconsolidates
intoa primarymassto
becomecontiguouswith the inner leafletof the cellsplasmalemma.A
localizedmicrotubulenetworkwasfoundto passmostprominantlyin the
thin basalaspectof the complex.The cross-sectional
orientationappears
to optimizethe visualizationof this potentiallyimportantaspectof the
outer hair cellsanatomy.
The majorityof proteinsfoundto datein OC wereidentifiedby immunohistological
methods.
Whilethesetechniques
arepowerfultoolsfor
localization
ofproteins,
theyfrequently
lacksatisfactory
specificity.
Twodimensionalpolyacrylamidc
gel electrophoresis
(2D-PAGE) is able to
WEDNESDAY AFTERNOON, 18 NOVEMBER 1987
UM LEARNING CENTER, 1:00TO 2:15 P.M.
Session
BB. Psychological
andPhysiological
Acousti
csV: Frequency
Discrimination
andPitchPerception
William M. Hartmann, Chairman
Physics
Department,MichiganState Unioersity,
EastLansing,Michigan48824
ContributedPapers
1:00
BBl. Tests of a modified energy-detector model of frequency
discrimination. David $. Emmerich, Wolfgang Ellermeier, and
Brenda Butensky{ Departmentof Psychology,StateUniversityof New
York at StonyBrook, StonyBrook, NY 11794)
Henning[J. Acoust.Soc.Am. 42, 1325-1334(1967)] proposed
a
modifiedenergy-detector
modelof auditorydiscrimination
anddetection.
Thismodel,aswellasseveralothermodels,predictsthat randomvaria-
tionsof theamplitudes
of thesignals
to bediscriminated
in a frequencydiscrimination
experimentshouldmakethetaskmuchharder.However,
$59
J. Acoust.$oc.Am.Suppl.1, Vol.82, Fall1987
Henning[J. Acoust.Soc.Am. 39, 336-339 (1966)] reportedthat, for
signalfrequencies
lessthan4000Hz, variationsin amplitudedid not lead
to theexpectedimpairmenton the frequency-discrimination
task.A reexaminationof this questionindicatesthat when the appropriatecontrol
comparisons
aremade,subjects
doin factshowthepredicted
impairment.
Neverthelessa secondexperimentsuggests
that this resultmay not providea goodtestof Henning's(1967) energydetectionmodelsincevariationsin pitch with intensity,which are not consideredin the model,are
likelyto beinvolved.For thisreason,a thirdexperimentwasconducted
in
orderto providean independenttestof the model.The resultsof this third
experiment
do not supporttheenergy-detector
model.
114thMeeting:Acoustical
Societyof America
S$9
1:15
Previous
research
hasdemonstrated
theinfant'sabilityto extractthe
virtualpitchofharmonic
tonalcomplexes.
In thepresent
study,weuseda
conditioning
procedure
toassess
7-month-old
infants'perception
ofpiteh
for inharmonic
tonalcomplexes.
Infantsinitiallydiscriminated
a pitch
change
from 160to 200Hz or viceversain harmonic
tonalcomplexes,
BB2. Detectingdynamicfrequencyshiftsof simpleand complextones.
RobertP. Carlyonand Richard$. Stubbs(MRC Instituteof Hearing
Research,
UniversityPark,NottinghamNG7 2RD, UnitedKingdom)
which containedeight consecutive
harmoniesbut no fundamentalfre-
Thresholds
for thedetection
offrequency
modulation
bya singlecycle
ofa 12-Hzsinusoid
wereobtainedfor carriersthatweresimpleor complex
tones.Two phases
of modulatorwereused,producingpercepts
of either
upwardor downwardfrequencyglidesduringthemiddleof thestimulus.
To ensurethatsubjects
baseddetection
on frequency
mooement,
boththe
phaseof the modulatingsinusoidand the startingfrequencies
were
randomizedfrom presentation
to presentation.
For pure-tonecarriers,
thresholds
( = minimumdetectable
frequency
swing/carrierfrequency)
wereconstantfor carrierfrequencies
of 800-2400Hz andincreased
below
800Hz. Thresholds
werelowerfor modulations
producing
theperceptof
an upwardglidethan for "downward"glides.This differencewasmuch
greaterat low cartierfrequencies.
Whenthecarrierwasa three-componentharmoniccomplex,thresholds
werealmostindependent
of itscenter
frequencybut increased
with decreasing
fundamentalfrequency.Thresholdsfor harmonicand for inharmoniccomplexes
werecompared.These
resultshaveimplicationsfor the recordingof voicepitch {e.g.,in signalprocessing
hearingaids).
quency.
Afterinfantsdiscriminated
theharmonic
complexes,
eachpartial'sfrequencywasshiftedupwardby 30 Hz to renderthe soundsinhar-
tannic. All infantswho discriminated
the inharmoniccomplexes
proceeded
to a categorization
stagein whicha randomized
sequence
of
threeinharmonic
complexes
(containing
six partials)comprised
each
pitchcategory
sothatthespectral
characteristics
of thetokenschanged
continuously
whilethepitchcategory
changed
onlyonchange
trials.The
harmoniccomplexes
werediscriminated
by 19 of 22 infants,while 16
infantssuccessfully
discriminated
theinharmonic
sounds.
However,
only
11infantscategorized
spectrally
different
sounds
consistently
withtheir
pitches,
suggesting
thatinfants
hadmoredifficulty
extracting
pitchfrom
inharmonic
complexes
thanfromharmonic
onespresented
in previous
research.[Work supported
by NSF andNICHD.]
2:00
1:30
BB3. Central spectrum models of dichotic edge pitches. W. M.
BBS. Pitch and timbre of inharmonictone complexes
of Baiinese
Hartmann (PhysicsDepartment,Michigan State University,East
"GenderWayang"instruments.
WernerA. Deutseh(Department
of
Lansing,MI 48824)
Sound,AustrianAcademyof Science,
A-1010,Vienna,Austria)and
Franz Fodermayr
(Department
ofMusicology,
University
ofVienna,A-
Thecentralspectrum
modelof Raatgever
andBilsen[J. Aconst.Soc.
1010 Vienna, Austria)
Am. 80, 429-441 (1986) ] successfully
accounts
for a numberofdichotic-
noisepitcheffects
andfor thelateralization
of thepitches.
The modelis,
however,
physiologically
implausible.
An improved
model,based
upona
neuraldelaylinehavingcoincidence
cellsthatobeythestatistical
rulesof
Thetonesof thescaleoftwoBalinese
"GenderWayang"instruments
havebeenstoredon computerdiskand are usedas testtonesin pitch
detectionexperiments.
The subjects
wereinstructedto identifythepitch
of theinharmonicinstrumenttonesby tuninga sinusoidal
testtoneon the
appropriate
pitchheightin a computer
controlled
up/downadaptiveprocedure.The experimental
resultssupportthegeneralambiguityof pitch
perception
in caseofinharmonictonecomplexes,
thougha certainpreferenceof thesubjects
on thelowestpartialcouldbeobserved.
Thisperceptual ambiguitycouldbe increased
furtherwhenthe firstpartialof the
instrumenttoneswasremovedby meansof narrow-band
digitalfiltering.
Basedonfrequency
analysis
dataof thenaturalsounds,
a synthesis
of the
figuration"melody"of theGenderWayangpiece"Lagndelem"
hasbeen
performed
in whichtheinharmonic
complex
toneshavebeenreplaced
by
harmonic
ones.Thecomparison
ofall three,theoriginalsoundprobes
and
the filteredand the synthesized
tonesshowsthe strongdependence
of
pitch on timbre.The resultsof the pitch detectionexperimentsare discussed
onthebasisofcriticalbandanalysis
andthecurrenttheoryof pitch
perceptionaspublishedby E. Terhardt (1972).
StemandColburn[$. Aconst.SOc.Am. 64, 127-140(1978) ], retainsthe
predictive
poweroftheRaatgever-Bilsen
model.It alsosuccessfully
predictstheresultsof newexperiments
wherethe Raatgever-Bilsen
modei
fails.Newexperiments
measure
therelativestrengths
ofHuggins
pitches
HP + andHP --, thelateralization
of thebinaural-edge
pitch(BEP),
thespectral
densitydependence
of theBEP,andthestrength
of generalized BEP, wherethe interauralphaseshiftmay haveany magnitude.
[Work supported
by theNIH. ]
1:45
BB4. Infants' extractionof pitch from inharmonictonal complexes.
MarshaG. ClarksonandRachelK. Clifton(Psychology
Department,
Universityof Massachusetts,
Amherst, MA 01002)
WEDNESDAY
AFTERNOON,
18 NOVEMBER
1987
UMS 4, 1:00 TO 3:05 P.M.
SessionCC. UnderwaterAcousticsIV: WedgeModel Propagation
Ding Lee, Chairman
Naoal UndermaterSystemsCenter,New London, Connecticut06320
Chairman's Intruduetio•l:00
ContributedPapers
CCI. Range-dependent
cot-an frequenciesin a three-dlmensionai
ocean
environment.
StewartA. L. QleggandSongR. Yoon (Departmentof
OceanEngineering,FloridaAtlantic University,BocaRaton,FL 33431)
Soundpropagation
in a three-dimensional
wedge-shaped
oceanenvi-
S60
J. Acoust.Soc.Am.Suppl.1, VoL82, Fall 1987
ronmentdemonstrates
significantray curvaturein a directionparallelto
thewedgeapex.The theoretical
prediction
of thisshowsthattheseeffects
are moresignificantat low frequencies
than at high frequencies;
consequently,thethree-dimensional
oceanactaasa range-dependent
acoustic
filter.This paperdescribes
an experimental
andtheoreticalinvestigation
of pulsepropagation
in a modelscalethree-dimensional
wedge-shaped
114thMeeting:Acoustical
SocietyofAmedca
S60
ocean.In the experimental
setupthe completeacousticfield couldbe
measuredfor a givensoumepositionand the wedgeanglecouldbe
changed.
Theresults
showgoodagreement
withtheidealized
modalsolutionof Buckingham,
anddemonstrate
howthe pulseis distortedas a
functionof range.Theyalsodemonstrate
howthecut-onfrequency
for
acoustic
propagation
increases
asa functionofrangeparalleltotheshoreline.
1:20
CC2. Scatteringin hasinsor horizontally refracting modes:Which is it?
C. H. Harrison (CAP Scientific,40-44 Coombe Road, New Malden,
SurreyKT3 4QF, United Kingdom)
In a largebasinthereare at leasttwo typesof 3-D ray pathsfrom a
sourceto a distantreceivervia the slopingbasinedge(other than the
directpath). Oneisthesimplescatteredrayat theseabed,
andtheotheris
the multiplereflectedray that steepens
in shallowwaterbut finallyturns
in the horizontalplanetowardsdeepwater (otherwiseinterpretedas a
horizontallyrefractingverticalmodecontribution[C. H. Harrison,J.
Acoust.Soc.Am. 65, 56-61 (1979)]). If the totalchangein headingof
thelatterray is 20, itselevationanglewill neverexceed0 [C. H. Harrison,
J. Acoust.Soc.Am. 62, 1382-1388(1977) ], andthepathmayexistdespitereflectionlosses
in realisticenvironments.
Therefore,if the topand
bottomsurfaces
areperfectlysmooth,therewill benoscattering
andthere
will certainlybemultiplereflection.
Conversely,
if thesurfaces
arerough,
themultiplereflection
will beinhibitedbut therewill definitelybea scatteredreturn. Sincethereis scopefor misinterpretation
of experimental
results,this paperproposes
someexperiments
to distinguishthe two
paths.
America in Indianapolis,Indiana, 11-15 May 1987. The underwater
acoustics
communitywasinvitedto presentsolutionsto theseproblems
andcomparethemagainsta numerically"exact"solutkmobtainedfrom
theR. B. Evans'coupledmodemodel[F. B. Jensen,
J. Acoust.Soc.Am.
Suppl.I 81, S40(1987)]. Ourfiniteelementoceanacoustic
propagation
model[J.E. MurphyandS.A. Chin-Bing,
J.Acoust.
Soc.Am.Suppl.1
81,S9 ( 1987) 1to ProblemI isappliedhere.(ProblemI dealtwithshallow
waterupslopepropagation
in a wedge-shaped
channel.)This finiteelementmodelgivesa full-wavesolution
forrange-dependent
acoustic
propagationwith accuracythat rivalscoupledmodemodels.The model'scapability will be demonstrated
by presentinga numericalsolutionto
ProblemI that comparesfavorablyto the Evans'coupledmodemodel
solution.[Work supportedby ONR/NORDA. ]
2:05
CC5. Soundinteractionwith a sloping,upward-refracting
oceanbottom.
HassanB.Ali, JuanI. Arvelo(NavalSurfaceWeaponsCenter,
CodeU-
25, White Oak, Silver Spring,MD 20903-5000),Anton Nagl, and
HerbertOberall(Department
of Physics,CatholicUniversity,
Washington,DC 20064)
Results
of a parobolic-equation
(PE) codeareshownfortheproblem
of soundinteractionwithan upsloping,
upward-refracting
oceanbottom.
Theyarecomparedwith the resultsof a coupled-mode
code[ J. F. Miller
etal., J.Acoust.Soc.Am. 79,562 (1968)] fora range-dependent
environment.Thisincludes
bottompenetration
effects
at modecutoffanda study
of howtheseareaffected
bythesound-speed
gradientandby theabsorptionin thesediment.
The bottompenetration
featuresarefurtherillumi-
natedbyemploying
Gaussian
soundpulses
andstudying
theirpropagation,illustrating
theeffects
ofbottompenetration
andreradiation
backup
into the water (as causedby the upward-refracting
bottomgradient},
arrivingaheadof the water-bornepulse.
1:35
CC3. Diffraction of sound by hard strips and truncated wedges.
Ivan Tolstoy(Knockvcnnic,CastleDouglas,SW ScotlandDG7 3PA)
Startingfromrigorousdiffractionsolutions
for single,hard,semi-infinitewedges,
it haslongbeenpossible
to construct
approximate
solutions
for morecomplexangularsurfaces[ A.D. Pierce,J. Acoust.Soc.Am. 55,
941-955 (1974)]. Demonstrated
hereisan exactprocedure
thatformulatesthe multiplescatterbetweenverticesof an angularbodyvia the
standardself-consistent
algorithm.This allowsoneto obtainthecorrect
diffractedfieldof eachvertex.Summingthesetogetherwith the relevant
incidentandimagefieldsleadsto an exactsolutionfor thefull soundfield.
Thisisdonehcrcfor thecaseof a planeharmonicincidentsoundfieldfor
( 1) a truncatedwedgeand (2) a hardstripof width l. Numericalresults
for the latter modelare shownto comparesatisfactorily
for all kl with
experimentaldata [H. Mcdwin etal., J. Acoust.Soc.Am. 72, 1005-1013
(1982) ]. This theoreticalprocedureyields,in the planewavecase,a for-
malestimateof theerrorincurredin the"doublediffraction"approximation (i.e., the procedurethat neglectsall but the first two termsof the
multiple
scatter
series).
Thiserrordecreases
likeeikt/klforincreasing
k/.
It isthenpossible
toconfirmtheoreticallytheobservation
of Medwinetal.
whoshowed
that,forthegeometry
oftheirstripexperiment,
thisapproximationis actuallyverygoodfor kl>• 3 and quiteadequatein the region
I < kl < 3, usingtheBiot-Tolstoyrigorousimpulsive
pointsourcesolutionfor theperfectwedge[ M. A. BiotandI. Tolstoy,J. Acoust.Soc.Am.
29, 381-391(1957)] for their double-diffraction
solution.[Work sup-
2:20
CC6. Sphericallysymmetricacousticpropagationacrossa fluid/fluid
boundary.
MichaelJ. Buckingham
(Departmentof OceanEngineering,
Room5-204,Massachusetts
Instituteof Technology,
Cambridge,
MA
02139)
The acousticfieldproducedby a pointsourceat thecenterof a fluid
sphere,whichitselfisimmersedin a fluidmedium,isof interestin connection with ambient noise in the Arctic Ocean. A solution for the field in the
internaland externalfluid domainsis presentedbasedon novelfinite
Hankel transforms. The method involves internal and external Hankel
transformations
of the Helmholtzequation,
whichintroduce
explicitly
theboundaryvaluesof thefieldandits spatialderivativeat thespherical
interfacebetweenthe two fluids.By combining
the resultantequations
withtheboundary
conditions
(continuity
ofpressure
andnormalcomponentof velocity)all theunknown
constants
aredetermined,
andon performingtheinverse
Hankeltransforms,
thefinalexpression
forthefieldis
obtained. The mathematical formalism of the finite Hankel transforms
introduced
herehastheadvantage
of beingableto handlecomplicated
boundaryconditions,whereaspreviousfinite Hankel transformtechniquesarelimitedto problems
involvingDirichlet,Neumann,or mixed
(i.e.,impedance)
boundaries.
[Thisworkwassupported
by theOfficeof
Naval Research,ContractNo. N00014-86-K-0325.]
portedby ONR. ]
2:35
1:50
CCA.Anaccurate
numerical
solution
toASABenchmark
ProblemI using
thefiniteelementmethod.Joseph
E. Murphy(Departmentof Physics,
University of New Orleans, New Orleans, LA 70148) and Stanley
A. Chin-Bing(Naval Ocean Researchand DevelopmentActivity,
NumericalModelingDivision,NSTL, MS 39529-5004}
A SpecialSessionon Numerical Solutionsof Two BenchmarkProb-
lemswaspresented
at the 113thMeetingof the Acoustical
Societyof
$61
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
CC7. Sound transmissionexperimentsfrom an impulsivesourcenear
rigid wedges.Saimu Li (ShandongCollegeof Oceanography,
Quindao,
Shandong,
People's
RepublicofChina)andC. S. Clay (Geophysical
and
Polar ResearchCenter,Universityof Wisconsin,Madison,WI 53706)
Experimental sound transmissionsin air from a spark source to a
small microphonewere made near rigid wedges.Two typesof experimentswere made. The first experimentswere transmissions
within an
approximately12øwedgeanda 52øwedge.The Biot-Tolstoywedgesolution [I. Tolstoy,WavePropagation
(McGraw-Hill, New York, 1973)]
was usedto calculatethe theoreticalimpulseresponse.
The "free air"
114thMeeting:Acoustical
Societyof America
S61
transmission
fromthe sparksourcewasconvolved
with the theoretical
transmission.
The transmissions
within thewedgegavefinitesetsof multi-
plereflections
or imagearrivalsanda diffraction
arrival.Thediffraction
wassensitive
to leaksat thewedgeapex.Theoryandexperimentmatched.
Thesecond
setofexperiments
wasmadeneara 270øwedge.Arrivalswere
the direct reflectionand the diffraction.The image reflectionwhen the
specular"reflectionpoint"wasverynearthewedgeapexwasof interest.
Comparisons
of dataandtheoretical
signalsusingBiot-Tolstoytheory
were excellent.Theoreticaldiffractionsignalscalculatedwith Trorey's
theory had poor matches[A. W. Trnrey, Geophysics35, 762-784
(1970) ].
2:50
CC8. Impulse response of density contrast wedge using normal
coordinates.D. Chu and C. S. Clay (Geophysicaland Polar Research
Center,Universityof Wisconsin,Madison,WI 53706)
WEDNESDAY
AFTERNOON,
18 NOVEMBER
The exactimpulseresponse
of a pointsourceto a rigid wedgewas
derivedby Biot and Tolstoy [I. Tolstoy, WavePropagation(McGrawHill, New York, 1973)]. The solutionby the experiments
hasbeenverified.The wedgehavingfree (pressurerelease)boundarieshasthe same
formastherigidboundarysolution[W. A. Kinneyetal., L Acoust.Soc.
Am. 73, 183-194 (1983) ]. Thesesolutionscannotbe applieddirectly to
many actual casessuchas oceanfloor, wherethe ratio of densityof the
basesedimentto that of the waterapproaches
neitherinfinite(rigid) nor
zero(pressure
release).
Thesolution
istheimpulse
response
toanisovelocity (v• = v2)anddensitycontrast(Pl •P:) wedge.It is an extension
of
thesolutiongivenby Blot andTolstoy.The reflectionpart of the solution
is an impulseseriesweightedby reflectioncoefficient
with differentorder.
The diffractionpart is the summationof the diffractionsdue to the individualimagesources.
The amplitudesarea functionof thereflectioncoefficientand the numberof multiplereflections.[This work waspartly
supportedby the People'sRepublicof China and the Officeof Naval
Research.]
UMS 5, 1:00 TO 3:05 P.M.
1987
SessionDD. Underwater Acoustics V: Noise Modeling
Tsih C. Yang, Chairman
Naval ResearchLaboratory,Code5123, Washington,DC 20375
Chairman's
Introduction--l:00
ContributedPapers
1:05
DDI. Low-frequency
noiseandbubbleplumeoscillations.
W. M. Carey
(Naval UnderwaterSystemsCenter,New London,CT 06320) and J.
W. Fitzgerald(Consultant,New London,CT 06320)
The evidencefor a wind dependencein low-frequencyambientnoise
( < 200 Hz) is sparsedue to the corruptinginfluencesof the radiated
soundfromships.Measurements
madewith hydrophones
belowcritical
depth,in sparseshippedbasins,or at highseastatesshowindications
of
twodistinctregimes
associated
withtheoccurrence
ofbreakingwavesand
a variationof root-mean-square
pressure
withthesquareof thelocalwind
speed.In a previous
paper[W. Carey,L Acoust.Soc.Am. Suppl.178,SI
( 1985) ], thegeneration
of soundby waveturbulenceinteractionat low
seastates(WS < 10m/s) andcollectivebubbleoscillations
drivenby turbulenceat highseastateswasproposed
(WS > 10m/s). Thispapershows
thatrecentlyobserved
bubblecloudsthat penetrateto tensof metersbelow the surfaceof the searesultin regionsof low sonicvelocitydescribed
by Wood'streatmentof air-bubblewater mixtures,but with a density
closeto that of water.It is shownthat sucha regioncan be treatedas a
flexiblebody with mixture speedand density.The radiationfrom sucha
bodywouldbemonopole
anddipolein nature;butdueto theproximityof
the seasurface,only the resultingdipolesourcewouldbe of importance.
Theseregionscouldalsohavea resonant
characteristic,
andwhendriven
by the turbulenceresult in sufficientradiated sound.These resultsare
similar to and consistentwith the analysisby A. Prosperetti [ Nato AS 1,
"Natural
Mechanisms
of Surface
Generated
Noise
in the Ocean"
(1987)1.
at thesoundchannelaxisandwereuniformlyspacedat half-wavelength
eitherat 200 or 300 Hz. From 75 to 300 Hz, the changein the vertical
distributionof noiseshifts,especiallyat higherfrequencies,
with increasingrangefromcoastalshippingwasin a mannerconsistent
withtheeffect
ofchemicalabsorption
onlow-anglenoiseduetocoastalshipping.
Whereasa shippingnoisepedestalat low anglesisobserved
at all frequencies
at
shortrange,at longrangetheabsorption
effectmakesthe verticaldistributionof ambientnoisemoreisotropicat higherfrequencies
thanthat at
lowfrequencies.
Effectsof windspeedontheverticaldistribution
of noise
werealsomeasured.As wind speedincreases,
ambientnoiseat angles
greaterthan 15øfromthe horizontal(that is, noiseof localorigin) increases
andapproaches
thelevelsof thepedestalat 124øW andpresumablyexceeds
themat highwindspeeds.
Our resultsareorthogonal
to those
obtainedbyKibblewhiteetal., ARL/UT, withtheirdeployment
at 150W
of threeVedabsbouyson a north-southline to measurelow-frequency
absorption
usingnorthernshippingasa soundsource.Thisconflictsuggests
a simultaneous
north-south
andeast-west
experiment
aswellasthe
utility of usinga multielement
verticalDIFAR array. [Work supported
by ONR. ]
1:35
DD3. Estimation of surface noise source level from low-frequency
seismoacoustic
ambient
measurements.
Henrik
Schmidt
Engineering 5-204, Cambridge, MA 02139) and W. A. Kuperman
(Naval ResearchLaboratory,Washington,DC 20375)
The extraction
1:20
noise
(MassachusettsInstitute of Technology, Department of Ocean
of noise source levels from ambient noise measure-
latitude of 32N at three stations, 124W, 136W, and 150W, the latter sta-
mentsrequiresaccountingfor the seismoacoustic
propagationfrom the
surfacegeneratednoisesourcesto the field measurement
positions.At
frequenciesbelow 100 Hz, the waveguidenature of the environment
stronglyinfluencesthe distributionof ambient noise.Only when these
propagation
effectsarc considered
canmeasurements
from differentexperimentstakenin differentenvironments
be combinedto ascertainthe
globalpropertiesof surfacenoisesources.
Here, sucha previousanalysis
of a shallowwaterexperiment[Schmidtet al., in NaturalMechanisms
of
SurfaceGeneratedNoise,editedby B. Kerman (Reidel, Dordrecht, The
tionbeingabout1700milesfromthecoast.The arraysusedweredeployed
Netherlands, 1988)] is usedand the resultsare combinedwith Kibble-
DD2. Effect of longitudeon vertical distributionof ambient noisedue to
wind and coastalshipl•ing.F. H. Fisher and W. S. Hodgkiss (Marine
PhysicalLaboratory,ScrippsInstitutionof Oceanography,Universityof
California--SanDiego,La Jolla,CA 92093)
Using multielementvertical arrays deployedfrom FLIP, measurements of the vertical distribution
$62
of ambient noise have been made at a
d. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
114thMeeting:Acoustical
Societyof America
$62
whiteandEwans'lower-frequency
results[J. Acoust.Soc.Am. 78, 981994( 1985) ], thelatteralsocontaining
a summary
ofprevious
experimental resultsobtainedby others.Thesedataaretreatedin thesamewayby
accounting
for theenvironments
usinga wavetheorymodelof distributed
noise[W. A. KupermanandF. Ingenito,J. Acoust.Soc.Am. 67, 19881996(1980)]. Whentheparticularenvironments
areused,thespreadin
thereprocessed
noiselevelsissubstantially
reduced,showingmoreconsistencyin the frequencydependence
of the noisesources,
suggesting
that
thereareonlya few (or possibly
onlyone) dominantnaturalnoisesource
mechanisms
that primarily contributeto oceanambientnoisebelow 100
Hz. The importanceof appropriately
includingpropagation
factorsin
processing
noisedatafor estimating
sourcelevelsis thereforestrongly
demonstrated.
1:50
DD4. Downslopepropagationand verticaldirectionalityof windnoise.
W. M. Carey (Naval UnderwaterSystemsCenter, New London,CT
06320), R. E. Evans(ODSI, Stonington,CT 06378), and J. A. Davis
(PSI, New London, CT 06320)
wind speedand rain rate, the soundgenerationmechanisms
remainobscure.This isduepartlyto thedifficultyof simultaneously
measuringthe
sound-generating
phenomenaat the locationof the acousticmeasurements.Also,thereisa lackof frequency
spectraof soundgenerated
bythe
specific
sources
thatmaydistinguish
betweenwind-andrain (or spray)generatedsoundandmay holdimportantcluesto the generatingmechanisms.A pier facility was established
on NarragansettBay to monitor
broadbandsoundassociatedwith observedseasurfacephenomena.Simultaneous
recordingof windvelocity,waveheight,andrain rateallows
precisecomparisonof the environmentalvariableswith their acoustic
response.
In addition,visualobservation
is madeof whitecapping
and of
interfering
shiptraffic.Theambientsoundspectraareroutinelygenerated
ashigh-resolution
FFT estimateson a MASSCOMP computer.Preliminarymeasurements
showsoundpressureto vary linearlywith wind speed,
withcorrelations
rangingfrom0.88-0.97.The slopechanges
aroundwind
speeds
of 6-7 m/s, i.e.,wherewhitecapsform,The spectraof wind-generatedsounddisplaya fasterroll-offthan rain-produced
sound,the latter
exhibitinga broad peakaround 15-18 kHz. Plotsare presentedof the
intenseinsonificationof the water column by rapidly advectingrain
squalls.[Work supportedby NAVSEA/AIRSEA systemscommands.]
Measurements
of theverticalnoiseintensityversus
angle[ W. Carey
and R. Wagstall',J. Acoust. Soc. Am. 80, 1523-1526 (1986)] show the
low-frequency
distribution(4200 Hz) to be broadlypeakedaboutthe
horizontal,whereasthe higher-frequency
(m400 Hz) distributionis
peakedat theSOFAR angles( m + 15) neartheaxiswith a minimaat the
horizontal.
Thiseffecthasbeenattributedtothenoisefromshipsoverthe
basinmargins[R. Wagstaft,
J. Acoust.Soc.Am. 69, 1009-1014( 1981) ].
However,sincespectralvariationalongthe horizontalis smoothand the
effectis observed
in sparselyshippedareasof the world,windnoisemust
bc includedto explainthiseffect.R. W. Bannister[J. Acoust.Soc.Am.
79, 41-48 (1986) ] hasattributedthiseffectto high-latitudewindsandthe
shallowingsoundchannelfound in SouthernHemispherewaters.W.
Carey [J. Acoust.Soc.Am. 79, 49-59 (1986)] attributedthe effectto
downslopepropagation.Calculationsbetween50 and 400 Hz of the midbasin vertical directionalitymade with ASTRAL and PAREQ with a
geoacoustic
modelwereboth foundto showthat the bottombehavesasa
low-passfilterasthelow-frequency
energyat higheranglesinteractswith
thebottomandisconverted
to low-angleenergyin thedeepsoundchannel while,at the higherfrequencies
andhigherangle,energyis absorbed.
This low-passeffectis consistent
with experimentalresults.Propagation
of low-grazingangleenergyfromtheshelfis prominentin thecomputationalresultsbut not apparentin measured
data,perhapsdueto bathymetricroughness.
2:05
2:35
DD7. Observationsof deep-oceanambient noise using a seismometer
array. AnthonyE. Schreiner,LeRoy M. Dorman,JohnA. Hildebrand,
Dalia Lahav (Scripps Institution of Oceanography,University of
California-SanDiego,La Jolla,CA 92037), and Dale Bibee(NORDA,
NSTL Station, MS 39529)
An arrayof 12ocean-bottom
seismometers
(OBS) wasdeployedthis
pastMarchin thedeepocean
nearSanDiego.Thearrayhada maximum
extentof 150m anda minimuminterelement
spacingof 8 m. The accuracy
of the relativesensorpositionswas as goodas 2 m in somecases.The
seismometers
weredeployedin 3.8km of waterwitha partiallymaneuverablevehicleat the end of a wire guidedby a transponder
net. The OBS
capsules
containeda verticalandtwo horizontalseismometers
anda hydrophone.
Threeof theinstruments
hada low-frequency
hydrophone
of
theCoxdesign.Three-minwindowswererecordedat intervalsof 3 or 6 h
forupto 30days.Spectrallevelshavebeencalculated
between
0.01and30
Hz. A powerlevel drop of up to 40 dB belowthe microselampeak at
frequencies
below0.1 Hz wasobserved.
Similarspectrahavebeenreported by Webband Cox [J. Oeophys.Res.91, 7343-7358 (1986) ]. At the
time of the abstractdeadline,correlationwasbeingcalculatedas a function of sensorseparation
to determinethecorrelationlengthof the ambient _noise.
DDS. Underwaternoiseproducedby rainfall. H. C. Pumphreyand L.
A. Crum (National Center for PhysicalAcoustics,The University of
Mississippi,Oxlbrd, MS 38677)
When a liquid drop falling throughthe air strikesa fiat horizontal
surface,thereareacoustic
emissions
associated
withthisimpactin both
theair andtheliquid [ G. J. Franz,J. Acoust.Soc.Am. 31, 1080(1959) ].
Undercertainconditions,
a smallair bubblecanbeentrainedin the liquid
by theimpactingdropandstimulatedinto volumepulsations
that radiate
quite strongly.When severaldrops impact the surfacein a short time
interval as in rainfall, the acoustic emissionsassociatedwith the bubble
oscillations
appearto bea majorcontributionto the total acousticemissionovera considerable
bandwidth.With artificiallycreatedrainfall, the
spectralpeakobserved
near20 kHz for naturalrainfallcanbeduplicated
[Scrimgeret al.:,J. Acoust.Soc.Am. 81, 79 (1987) ]. However,with the
additionof surfacetensionreductionagents,thispeakissignificantly
reduced,implying that a major portion of the noiseassociatedwith rainfall
is related to oscillations of the entrained bubble rather than due to the
impact of the drop with the liquid surface.[Work supportedby the
ONR. ]
2:20
DD6. Correlation and spectra of ambient sound generatedby wind,
whitecaps, and rain. David Shonting (Naval Underwater Systems,
Center, Newport, RI 02841), Foster Middleton (University of Rhode
Island, Kingston, R1 02881), and Nancy Taylor (Applied Science
Associates,
Narragansett,RI 02882)
Althoughhighcorrelationexistsbetweenoceanicambientsoundand
$63
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall 1987
2:50
DDS.
Ambient
ULF/VLF
ocean-bottom noise 200 km west of San
Francisco: Motion and pressure 0.002 to 20 Hz. G. H. Sutton, J.
A. Carter, and N. Barstow (Rondout Associates,Incorporated,P.O.
Box 224, StoneRidge, NY 12484)
Data recordedfrom long-periodand short-period,three-component
seismometers
and hydrophones
of the Columbia-PointArena ocean-bottom seismicstation(OBSS) are beinganalyzedin the frequencyrange
0.001 to 40 Hz to determine the characteristics of ULF/VLF
ocean-bot-
tom noise. The OBSS, located at 38ø 09.2' N, 124ø 54.4' W at 3903-m
depth, operatedfor over 6 years,from May 1966 to September1972.
Selected
portionsof essentially
continuous
FM tapedataarebeingdigitized to obtainULF/VLF spectraand covariances
duringquietand noisy
times and during passageof vesselsand earthquakewavetrains.It is
plannedto compareOBSSdatawith availablesourceinformationon sea/
swell conditions, tidal currents (measured by a current meter on the
OBSS), earthquakes,and shipping.Spectrallevelsappear to be above
systemnoisefor mostfrequencies
aboveabout0.002 Hz. The pressure
spectraagreewith thoseobtainedmore recently [Cox et al.,Atmos.
OceanicTech. 1, 237-246 (1984) ], showinga strongminimumbetween
about0.03 and 0.1 Hz. The motion spectrafrom the OBSS seismometers
are similar.Coherencybetweenverticalmotionandpressureiswell above
random for most of the spectrumbelow 0.5 Hz. There is clear evidence
that ambient noise maxima rise and fall with weather conditions and wa-
ter waveactivityand that ULF noise,especiallyon the horizontalseismometers,hasa tidal dependence.[Researchsupportedby ONR.]
114thMeeting:AcousticalSocietyof America
S63
WEDNESDAY AFTERNOON, 18 NOVEMBER 1987
TUTTLE SOUTH ROOM, 1:30TO 3:00 P.M.
SessionEE. Noise IV and EngineeringAcousticsIII: Applicationof Math Models and Experimental
Investigationsto SolveAcousticProblems(PosterSession)
Larry H. Royster,Chairman
1217BR Hall, M•4E Department,North CarolinaState University,
Raleigh,North Carolina27695-7910
ContributedPapers
All posters
willbedisplayed
from1:30to 3:00p.m.To allowcontributors
theopportunity
toseeotherposters,
contributors
of odd-numbered
paperswill beat theirposters
from 1:30to 2:15p.m.andcontributors
of evennumberedpaperswill beat theirpostersfrom2:15to 3:00p.m.
EEL Boundary elementsolutionfor a coupledelastodynamicand wave
equation
system
to predictforcedresponse
of a plugged
acoustic
cavity.
Robert Ciskowski (International BusinessMachines, Rochester, MN
55901) andLarry H. Royster(Departmentof MechanicalEngineering,
North CarolinaStateUniversity,Raleigh,NC 27695-7910)
The subjectof this investigation
is the useof the boundaryelement
method(BEM) to predictthe steady-state
and transientresponse
of a
plugged acoustic cavity to external excitation. The plug is an
clastodynamic
materialsubjectto externalexcitation.The excitationof
theplugistransmitted
to theacoustic
cavity.No internalsources
of excitationare considered.
A three-dimensional
BEM modelis developedfor
theanalysis,bothfor thefluidin thecavityandtheclastodynamic
material in contactwith it. Transientresponse
is determinedby recoveringthe
timedomainresponse
from the Laplacetransformdomainsolutionusing
conditionrequirementson the acousticvariables'valuescomposingan
acousticpulsewill beaddressed
and resultsfor the numericallysimulated
propagationof sucha pulsewill be shown.Further, an extensionto the
abovemodelfor atmosphericpropagationcurrentlybeingtestedwill be
described
that includesbothclassical
and molecularrelaxationabsorption effects.Spacepermitting,the implementation
of our programson a
CRAY X-MP supercomputer
will becommented
upon.
EF_A.An on going study of the use of the boundary element method to
solve some of the more commonly encountered industrial noise and
an FF"r-basedinversionscheme.Steady-stateresponseis obtainedfrom
the Laplacetransformdomainsolutionby settings = -- iw. The numeri-
vibration control problems. Kassem M. Mourad (Department of
MechanicalEngineering,North CarolinaStateUniversity,Raleigh,NC
calcodeis designed
to run on theIBM familyof personal
computers
and
27695-7910), Robert D. Ciskowski (International BusinessMachines,
workstations.
Rochester,MN 55901), and Larry H. Royster (Department of
MechanicalEngineering,North Carolina StateUniversity,Raleigh, NC
27695-7910)
EE2. Transmission loss studies of muffler and duct systemsby the
boundary element method. C. Y. R. Cheng and A. F. Seybert
(Department of Mechanical Engineering, University of Kentucky,
Lexington,KY 40506-0046)
The presentpaperdealswith transmission
lossstudiesof acoustical
mufflerand duct systemsusingthe boundaryelementmethod(BEM).
Resultsobtainedby usingthis approachare presentedfor both axisymmetric and fully three-dimensionalmodels.The transmissionlossof a
mufflerelementcan be computedusingthe transfermatrix approach.
A studyis underway to establishthe advantages
or disadvantages
of
usingthe boundaryelementmethod(BEM) to obtainsolutionsto some
of themorecommonlyencountered
noiseandvibrationcontrolproblems
encountered
in generalindustry.Initial investigations
includepredicting
the steady-stateand transientroom-volumeSPL responsefrom internal
and boundaryacousticsourcesfor variousboundaryimpedances.
The
numericalcodedeveloped
to obtainthesolutions
of suchproblems
was
designed
to run on the IBM familyof personalcomputers
and workstations.
This method is ideally suited for the BEM becauseonly the valuesof the
unknownsat the inletandoutletboundaries
are required.The BEM valuesare comparedto theoreticalpredictionsand other availabledata such
as finite clementdata, and goodagreementis obtainedwithin a broad
frequency
range.
It canbeconcluded
thattheBEMshould
givereliable
estimates
of transmission
lossin practicalsituations.
[Work supported
in
part by ASHRAE. ]
EE5. Plane-waveexcitationof an infinite circularcylinderreinforcedby
a periodicset of rings.FrancoisDe Maigrct (Thomson-SintraA.S.M.,
Route desDolines, Parc de Valbonne,B.P. 38 06561, ValbonneCedcx,
France)
Analyticalexpressions
are derivedfor the scatteredfieldby an infinite
EE3. Finite differencemodelingof acousticpulse propagationin the
atmosphere.Victor W. Sparrow (Department of Electrical and
Computer Engineering,University of Illinois, Urbana-Champaign,
Champaign,
IL 61820andUSA-CERL, P.O.Box4005,Champaign,
IL
61820-1305)andRichard Raspet(PhysicalAcousticResearchGroup,
The University of Mississippi,University, MS 38677)
In a previouspresentation
[J. Acoust.Soc.Am. Suppl.1 g0, S104
(1986)], theuseof a finitedifference
approximation
of thetime-dependentacoustic
equations
forarbitraryaxisymmetric
pulses
wasdescribed.
In thatpaper,however,onlytheapplication
of theseequations
for a time
harmonicsimplesourcewasdemonstrated.
In thepresentation,
theinitial
S64
J.Acoust.
Soc.Am.Suppl.
1,VoL82,Fall1987
fluid-loaded
cylindricalshellreinforced
withtheperiodicsetof ringsand
acousticallyexcitedby an incidentharmonicplanewave.Vibrationsof the
shellare treatedusingthin bendingcylindricalshelltheoryby Kennard.
The stiffenerainteract with the cylindricalshell only throughnormal
forces.Unknownquantities(i.e., scatteredacousticfield,displacements
of theshell)areexpandedon the naturalBloch-Floquetbasisinducedby
thestructureperiodicity.Numericalsimulations
ona widerangefrequen-
cy are reported,wherethe dimensionless
product"ka" of the incident
fluidwavenumber
bytheshellradiustypicallyextends
from10-2 to 102,
usinga uniquealgorithm.Numericalpredictionsare comparedwith experimentaldata on differentphysicalsituationsshowinga goodagreement. [Work supportedby GERDSM.]
114thMeeting:
Acoustical
Society
ofAmerica
S64
EE6.Effectof background
noi•eonsound
powerestimates
usingthe
EE9. Effect of a •emicircular diffuser on the soundfield in a rectangular
soundintensitytechnique.U.S. Shirahatti,Malcolm J. Crocker,and P.
K. Raju (Departmentof MechanicalEngineering,Auburn University,
Auburn, AL 36849)
room.Pan Jie and D. A. Bies(Universityof Adelaide,Departmentof
MechanicalEngineering,G.P.O. Box No. 498, Adelaide,S.A. 5001,
Thepresence
ofa background
noisesource
affects
theaccuracy
of the
estimateof the •ourcesoundpowerlevel.In thispaper,the resultsof a
systematic
experimental
studyon the accuracyof estimation
of sound
powerlevelsin thepresence
ofa background
noisesourcearcreported.A
calibratedsoundpowersourcewasusedin theseexperiments.
The sound
powermeasurements
weremadeusingthetwo-microphone
soundintensitytechnique.
Theerrorsin theestimates
of thesoundpowerlevelof the
Previousexperimental
workhasindicatedthe influence
of a rotating
diffuseruponthe diffusionof a reverberation
field,uponthe radiation
impedanceof a soundsourcein a reverberation
room, and uponthe
boundaryabsorptions.
Someinteresting
resultsofthisworkneeda quantitativeinterpretationwhileotherssuggest
an effectiveinvestigation
to obtain a detailedphysicalinsight.In an effortto findan insightinto andan
interpretation
of thiswork,an analyticalapproach
is presented.
Thispaperisan interimreportoncontinuingresearch,
andit reviewsan investigationof the effectof a semicirculardiffuseruponthe two-dimensional
soundfieldin a rectangularroom.The numericalrelationship
betweenthe
resonance
frequencies
oftheacoustical
modesin theroomandthediffuser
orientationis given.The sound-prcssurc
distributionsof the acoustical
modesarc alsogivenasthe functionof the diffuserorientation.A thrcedimensionalcavityis usedfor experimentalverification.In this cavity,
onlythesoundwavesin thehorizontalplanewill beaffected
bya diffuser.
The experimentaland numericalresultsagreeclosely.
calibrated sound source were determined for different levels of back-
groundnoise.Also,a systematic
studywasmadeon the relationship
betweenthe numberof pointsof measurement
on the enclosing
surface
definedaroundIhe sourceandtheaccuracyof thesoundpowerestimate.
It hasbeendemonstrated
that the accuracyof soundpowerestimatesis
greatlyimprovedby continuous
handscanning
of theenclosing
surface
insteadof by makingmeasurements
at a smallor moderatenumberof
fixedpoints.Thelocalsoundpressure
minusintensityindexandtheglobalsoundprcssu
rcminusintensityindexarcusedasindicators
of thedata
quality.[Work supported
by IBM, Charlotte,NC.]
EE7. Acousticradiation from plates driven by multiple point random
forces.H. Peng and R.F. Keltie (Center for Sound and Vibration,
Departmentof MechanicalandAerospaceEngineering,North Carolina
StateUniversity,Raleigh,NC 27695-7910)
The problemof acousticradiationfromplatesdrivenby multipleran-
dompointforcesis analyzedin thisstudy.First,theformulation
of the
soundpowerradiatedby infinitethin plates(one dimension)underthe
actionof multiplerandompointforcesis derived.The reactionof the
acousticmediumon thevibratoryresponse
of platesistakenintoaccount.
With theinputspectrumbeingassumed
asbandlimitedwhitenoise,the
effectsof input forcecorrelationon the radiatedsoundpowerlevelare
examined.The analysisis then extendedto finite thin plateswith four
simplysupported
edges.
Thefluidloadingeffects
areneglected.
The exact
expressions
for thesurfaceacoustic
intensityandtheradiatedsoundpower arealsoderived.Assuminglight damping,approximate
solutions
for
acousticintensityand soundpowerareobtained.An experimental
study
is carriedout to measurethe surfaceacousticintensitypatternsand com-
parewith theanalyticalresults.The effectsof inputforcecorrelationon
theacousticintensitypatternsandthesoundpowerlevelarediscussed.
EE8. Prey detectionby meansof passivelisteningin bottlenosedolphins
{Tursiopstruncatus}. N61io B. Burros and Arthur A. Myrberg' Jr.
(RSMAS-BLR, Universityof Miami, 4600 RickenbackerCauseway,
Miami, FL 33149-1098)
Australia)
EEl0. The applicationof thecepstrumtechniqueto theseparationof the
input signaland the structureresponse.Mei Q. Wu and Malcolm
I. Crocker (Department of Meehanical Engineering,Auburn
University,Auburn, AL 36849)
In thispaper,aniterativealgorithmfortheeepstrum
ispresented.
The
improved
cepstrum
technique
isappliedtoseparate
theinputsignalfrom
theresponse
of a structure.
It isprovedthatif theinputsignalisan impulseandthefrequency
response
ofthestructure
isbandlimited,
thenthe
frequency
response
function
of thestructure
canbedetermined
fromthe
outputof thestructure
withoutanyprcknowledge
of the inputsignal.
Furthermore,
thespectrum
oftheinputsignalcanbedetermined
fromthe
structureresponse
functionand the output spectrum.Somecomputer
simulated
experiments
havebeenconducted.
The experimental
results
showthatthefrequency
response
functionrecovered
byusingtheiterative
algorithmconverges
to thecorrectresponse
function,andfor about30
timesof iterationthe recovered
response
functionis verysimilarto the
correctresponse
function.[Worksupported
byIBM, Austin,TX. ]
EEII. Subjectiveevaluationof a test earmuffexhibitingfiat attenuation
withnonlinearcharaeterlsties.
JuneL. Peters(Departmentoflndustrial
Engineering,
North CarolinaStateUniversity,Raleigh,NC 27695),
Larry H. Royster(Departmentof MechanicalEngineering,
North
CarolinaStateUniversity,Raleigh,NC 27695), JuliaDoswellRoyster
( EnvironmentalNoiseConsultants,Inc., Cary, NC 25712), and Richard
Free-livingbottlenosedolphins(Tursiopstruncatus)are primarily
piscivorous
andtheuseof activeecholocation
hasbeenimplicatedin prey
capture[K. S. Norris and B. M6hl, Am. Nat. 122, 85-113 (1983)]. Re-
G. Pearson(Departmentof IndustrialEngineering,
North Carolina
cent evidence ba.•xt on the examination of stomach contents of more than
Subjective
userresponses
wereobtained
for a testearmuffexhibiting
approximately
flat attenuation
of about25 dB from 500-8000Hz for
70 individualsfrom the southeastern
United Stateshassuggested
that
bottlenosedolphinsalsolikely use passivelisteningfor the purposeof
detectingandpossibly
orientingto theirprcy.The mostfrequentlyoccurringpreyspecies
(i.e.,thosefoundin morethan ! 5% of thesample)werc
invariablythoseknownto be highlyactivesoundproducersand, in all
instances,
producersof soundsof highlevel(e.g., croakersanddrumsof
the family Sciaenidae,
gruntsof the family Haemulidae,toadfishes-midshipmenof thefamilyBatrachoididae,
andmulletsfromthefamilyMugilidae).Althoughin severalinstances
members
of somespecies
couldhave
beencapturedby activeecholocation
and visualmeans,it ishighlyunlikely that membersof otherspecies,
by their highlysecretivehabits,would
havebeencapturedby suchmethods(i.e., membersof the family Batrachoididae).Data from other regionscorroboratethe abovementioned
findingsthat fishproducingloud soundcomprisethe bulk of the diet of
bottlenosedolphins.
S65
J. Acoust.Soc. Am. Suppl. 1, VoL 82, Fall 1987
StateUniversity,Raleigh,NC 27695)
SPLs lessthan 115 dB, with attenuation increasingnonlinearly up to
about10 dB at higherSPLs.The studypopulationconsisted
of police
officers
performing
annualgunfirerequalification,
in whichofficers
executerequiredtargetshotsduringtwo sequential
relayexercises.
In the
firstphaseof thestudy,subjects
woreeithertheirregularhearingprotector or thetestmuffduringthefirstrclay,thenthealternateprotectorfor
thesecond
rclay( withordercounterbalanced).
In thesecond
phase,
additionalsubjects
woreeithera controlearmuffthatwasidenticalto thetest
earmuffexceptfor the nonlinearmechanism(alsoeliminatingthe flat
response
characteristics)
or the testearmuff.Subjects
completed
questionnaires
concerning
theiropinionsof thehearingprotectors
wornduring both phases.Preliminaryresultsindicatea significant
differencein
favor of the test earmuffin threeareas:speechunderstanding,perceived
levelof protection,
andcomfort.
114th Meeting:AcousticalSocietyof Amedca
S65
farfieldsolution.The nonlineareaseof strongscatteringin the inhomogeneous
mediumis considered.
The Feynmanpathintegralis appliedto
theproblem,andthiscangivethesolutionin closedform.Previousworks
[M. SlaneyandA. C. Kak, paperat the 1985IEEE Ultrason.Syrup.;and
Z. Q. Lu, IEEE Trans.Ultrason.Ferroelectries
andFrequencyControl
UFFC-33(6), 722-730 (1986) ] cannotgivethe solutionin closedform.
The pathintegralisbasedon theactionprinciple(variationalprinciple).
Here, the Schr'ddinger
equationwill be used.The scatteringintegrals,
EEl2. A generalized
theoryfor acoustical
holography
and acoustical
diffractiontomography.
W. S. (}an (AcousticalServicesPte Ltd., 29
TelokAyerStreet,Singapore
0104,Republicof Singapore)
A generalzied
theoryisproposed
tocombine
acoustical
diffraction
tomography(ADT) withacoustical
holography
(AH) totakeaccount
ofthe
diffraction
andscattering
duringtransmission
ofsoundwavesthroughan
inhomogeneous
medium.Thisis usuallyneglected
in AH but mustbe
considered
if themediumis inhomogeneous.
In thisgeneralized
theory,
perturbation
expansion
of thescattering
potential,andthewavefunction
are all expressed
in termsof the path integrals.The algorithmof the
imagingprocess
for the generalizedtheoryis given.
AH is a nearfieldsolutionof the HelmholtzwaveequationandADT is a
WEDNESDAY
AFTERNOON,
18 NOVEMBER
1987
UNIVERSITY
LECTURE HALL, 2:15 TO 3:15 P.M.
Session FF. Architectural Acoustics IV: Technical Committee on Architectural Acoustics
V. O. Knudsen Distinguished Lecture
William J. Cavanaugh,Chairman
Cavanaugh
TocciAssociates,
Inc., 327 F BostonPostRoad,Sudbury,Massachusetts
01776
Chairman's
Introduetion--2:15
Invited Paper
2:20
FFI. Designingfor the performingarts:An historicaloverview.Michael Forsyth(Departmentof Drama,
Universityof Bristol,29 Park Row, BristolBS1 5LT, United Kingdom}
A relationship
developed
historically
between
theacoustics
of differentauditorium
typesandcorrespondingstyles
ofmusical
composition.
Thisresulted
fromthecornposer's
intuitiveawareness
ofroomacoustics,
and
fromthe architect's
limitedknowledge,
basedon trial and error,of the acousticperformance
of building
materialsandroomshapes
in providingfor differentpurposes.
Exceptwherecomposers
havehadauditoria
specifically
designed
for theirownmusic,thisrelationship
becametenuous
in the presentcenturywhenthe
musicalrepertoire
broadened
andwhennonmusical
criteriacameto dominate
thedesignprocess.
An auditorium'ssuccess
nowdepends
ontheinitialselection
ofacoustical
andothercriteriain relationtothebuilding's
defined
purpose
andonthetranslation
ofacoustic
theoryintothree-dimensional
form.Thesefactors
together
determine
theaudience-performer
relationship
andtheshapeanddimensions
oftheenclosing
surfaces.
Historical examples
illustrateearlyattemptsto projecttheoryinto built form,and othersfrom the presentday
describe
theproblemof integratingopposing
acousticdemands.
S66
J.Acoust.
Soc.Am.Suppl.1,Vol.82,Fall1987
114thMeeting:
Acoustical
Society
ofAmerica
S66
WEDNESDAY AFTERNOON, 18NOVEMBER 1987
ORCHID B ROOM, 2:00P.M.
Meeting of Accredited StandardsCommittee S2 on Mechanical Shock and Vibration
to be heldjointly with the
TechnicalAdvisoryGroup(TAG) Meeting for ISO/TC 108 MechanicalVibration and Shock
J. C. Barton, Chairman S2
CaterpillarTractorCompany,
Research
Department,100N.E. Adams,Peoria,Illinois61629
G. Booth,Chairman,TechnicalAdvisoryGroupfor ISO/TC 108
220 Clark Avenue,Brandford,Connecticut
06405
Standards
CommitteeS2 onMechanicalShockandVibration.Workinggroupchairswill presentreportsof
theirrecentprogress
onwritingandprocessing
various
shockandvibrationstandards.
Therewillbea reporton
the interfaceof S2 activitieswith thoseof ISO/TC 108 (the TechnicalAdvisoryGroup for ISO/TC 108
consists
ofmembers
ofS2,S3,andotherpersons
notnecessarily
members
ofthosecommittees)
including
plans
for thenextmeetingof ISO/TC 108,tobeheldin September
1988.
WEDNESDAY
AFTERNOON,
18 NOVEMBER
1987
UM AUDITORIUM,
3:30 TO 5:00 P.M.
Plenary Session
Chester M. McKinney, Chairman
President,AcousticalSocietyof America
Presentation
of Awards
DistinguishedServiceCitation to FrederickE. White
HonoraryFellowshipto Henrik A. S. N4dtvedt
SilverMedal in Psychological
and Physiological
Acousticsto EberhardZwicker
SilverMedal in SpeechCommunicationto Dennis H. Klatt
Trent-Crede Medal to Miguel C. Junger
Local musical entertainment
S67
J.A,coust.
Soc.Am.Suppl.
1,Vol.82,Fall1987
will conclude the session.
114thMeeting:
Acoustical
Society
ofAmerica
S67
THURSDAY
MORNING,
19 NOVEMBER
1987
POINCIANA
ROOM, 8:30 TO I 1:50 A.M.
SessionGG. Musical AcousticsI: Extended Vocal Techniques,and Production and Perceptionof Music
Gary L. Gibian, Chairman
Department
of Physics
and•4udioTechnology,
•4merican
University,
Washington,
DC 20016
Chairman's Introduction---8:30
Invited Paper
8:35
GG1. Harmonic singing and the Harmonic Choir. David Hykes (The Harmonic Arts Society, 1047
Amsterdam Avenue, New York, NY 10027)
In harmonicsinging,thesingeremphasizes
a selected
upperharmonicofthevocalpulse.In thisway,hecan
singtwo notesat once,thefundamental
andtheselected
harmonic.Membersof the HarmonicChoirhave
developedtechniques
for the followingeffects:( l ) The fundamentalis constantwhile the selectedharmonic
varies;(2) the fundamentalvariesin a melodywhile the selectedharmonicremainsconstant,leadingto
parallelharmony;(3) boththefundamental
andtheselected
harmonic
vary,eitherin converging
or in divergingdirections.
TheChoirtogether
performs
unaccompanied
workswhicharecomposed
butnotscored.
Differentperformances
followa commonpathbut differin manydetails.
ContributedPapers
9:20
9:50
GG2. Regional cerebral blood flow for singers and nonsingerswhile
speaking, singing, and humming a rote passage. C. Formby
GCr4. Modal analysis of a Caribbean steel drum. Uwe I. Hansen
(Departmentsof CommunicativeDisordersand Neurology,University
of Florida, Gainesville,FL 32610) and R. G. Thomas(Departmentof
Biometry,EmoryUniversity,Atlanta, GA 30322)
Two groups of singers(n = 12,13) and a group of nonsingers
(n = 12) eachproducedthe nationalanthemby (1) speakingand (2)
singingthe words,and by (3) hummingthe melody.Regionalcerebral
bloodflow (rCBF) wasmeasured
at restandduringeachphonationtask
from sevenareasin eachhemisphereby the 133-Xe-inhalationmethod.
Global,intrahemisphere,
andinterhemisphere
rCBF weregenerallysimilar acrossphonationtasks and did not yield appreciabledifferences
amongthe nonsingers
and the singers.From theserCBF data, it was
concluded
that: ( 1) thenormalproductionof a familiarpassage
by speaking, singing,or hummingrequiresthe interactionof bothcerebralhemispheres
moreor lessequallyand (2) thesetasksarerelativelyindependent
(Department of Physics,Indiana State University,Terre Haute, IN
47809) and Thomas D. Rossing (Department of Physics,Northern
Illinois University,DeKalb, IL 60115)
Modesof vibrationand couplingbetweenadjacentnote areasin a
double-second
steeldrum are comparedby severalcomplementary
techniques,includingimpactmodalanalysis,holographicinterferometry,and
recordingsoundspectraundervaryingconditionsof damping.Eachnote
has at least one overtone mode tuned to a harmonic
of the fundamental
frequency.
StrikingtheA• notearea,forexample,
excites
notonlya secondharmonicA• in thatsamenoteareabut alsothestrategically
located
A} andA} noteareasadjacent
to it. Thecoupling
depends
uponamplitudein a nonlinearway.
of musicaltraining. [Researchsupportedby NIH. ]
10:05
9:35
GG3. Note coupling in Caribbean steel drums. D. Scott Hampton,
Clifford Alexis, and Thomas D. Rossing (Department of Physics,
Northern Illinois University,DeKalb, IL 60115)
The acousticalbehaviorof Caribbeansteeldrumsis characterizedby
strongcouplingbetweenthe differentnoteareasIT. D. Rossirig,D. S.
Hampton, and J. Boverman,J. Acoust. Soc. Am. Suppl. I 80, S102
(1986) ]. This makesit difficultto maintaintuningstability,especially
in
the harmoniesof the variousnotes.An improvednewdesignmakesuseof
doublegroovesto separatethevariousnoteareas.By meansof holographic interferometry,the note couplingwascomparedin two comparable
doublesecond(alto) drums,onewith singlegroovesandonewith double
grooves.
The drumwithdoublegroovesexhibitslessinternotecouplingat
highamplitudes,andbettertuningstability.
S68
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
GGS. Physical correlates of perceptual similarity among synthesized
approximations to selected targets. G. L. Gibian, D. R. Clements,
E. N. Hamden, H. E. F. Williams, and R. K. Massaro (Physics
Department,AmericanUniversity,Washington,DC 20016)
Experimentsare describedto evaluatethe relativemeritsof several
measures
for predictingthe perceivedcloseness
of synthesized
approximationsto selectedsteady-state
portionsof musicaltones("targets").
Approximations
weresynthesized
bymeansof audio-rate
frequency
modulation[Crowning,J.AudioEng.Soc.21,526-534( 1973) ] usinga computer programdevelopedin a previouspaper [Gibian et al., J. Acoust.
Soc.Am. Suppl. 1 81, S46 (1987), and Audio EngineeringSocietyPreprint #2380]. The importanceof includinglevel-and frequency-dependent error weightingsaccordingto the Fletcher-Munsoncurveswill be
assessed.
This informationcan be usefulto composerswho are blending
electronic and traditional instruments in mixed ensembles.
114thMeeting:Acoustical
Societyof America
$68
10:20
GG6.Comprehensive
studyofanalysis
andsynthesis
oftones
byspectral
bowpressure,
follows
asa special
case.[Worksupported
in partbyNSF
and the French Ministry of Culture.]
interpolation. RogerDannenberg, Marie-HcleneSerra, and
Dean Rubin (Center for Art and Technology,CarnegieMellon
University,Pittsburgh,PA 15213)
A newapproach
to thereal-time
generation
of digitalsounds
usesa
completely
automated
analysis/synthesis
technique
for naturalsounds.
Thisapproach
leadsto a moreefficient
implementation
thanclassical
additivesynthesis;
moreover
it allowsdynamicspectralvariations
to be
controlled
withonlya fewhigh-level
parameters.
Additivesynthesis
devicesrequirea largenumberof oscillators
(onefor eachpartial).This
technique
givesexcellent
results;
however,it requires
a largeamountof
computation,
and a largeamountof controldata. On the otherhand,
11:05
GG9. Impedancecharacteristics
abovecutofffor clarinet-likestructures.
William J. Strong(Departmentof Physicsand Astronomy,Brigham
YoungUniversity,Provo,UT 84602)
Thecutofffrequency
determined
by theopentoneholesona clarinet-
fixed-waveform
synthesis
usesonly one oscillator,but the resultsare of
like structureis a usefulmeansfor characterizing
thestructure'smusical
poormusical
qnalitysincethereisnodynamic
evolution
ofthespectrum.
properties.
[See,for example,thediscussion
anddatain A. H. Benade,
FundamentalsofMusicalAcoustics
(OxfordU.P., London,1976),Chaps.
21-22; noteSec.22.5 in particular.]Whenimpedance
peaksabovethe
A new techniquehasbeeninvestigated
in whichspectralvariation:is
achieved
through
spectral
interpolation.
Theresearch
shows
thatspectral
interpolation
provides
high-quality
synthesis
including
controlled
timbrai
variationat littlemorethanthecostofa table-lookup
oscillator.
Thetask
of analyzingdifferentkindsof instrumental
soundsto producecontrol
informationfor thistechnique
hasbeenautomated.
cutofffrequency
haveamplitudes
thataresignificant
fractions
of those
belowcutoff,theymay influence
theclarinetreedvibration.The input
impedance
of a clarinet-like
structure(a cylindrical
tubein thepresent
case)is influencedby its inputandoutputterminations.
Threeinput terminationsare considered:
(1) rigid cap, (2) rigid taper,and (3) rigid
taperwithreed.Several
outputterminations
areconsidered
including
( 1)
openend,(2) "infinite"toneholelattice,(3) "short"toneholelattice,
and (4) shortlatticeplusbell.Input impedances
arecalculatedfor variouscombinations
of the inputandoutputterminations
to demonstrate
theireffects
on theamplitudes
of theinputimpedance
peaksbothabove
10:35
and belowthe cutofffrequency.
GG7.Nonuniformity
in timbreof stringinstruments.
Asbj•JrnKrokstad
(Division of Telecommunications,
The NorwegianInstitute of
Technology,
N.7034Trondheim,Norway)
Mechanical
musicalinstruments,
mayshowgreatvariationof all
physicalpropertiesthat correlateto timbre,evenoverintervalsof a semitone.To examinepreferences
andlimitsofacceptability,
timbrevariations
havebeenstudied
in a melodic
context.A shortmelodyof 13tonescover-
inga decime
Wasplayed
bytwoprofessional
musicians
onthreeviolins
anda viola,andrecorded
at two microphone
positions
in an anechoic
room.Eachtonewasprocessed
digitallyto reducedifferences
in loudness
andin transients.
In thefirstoftwolistening
tests,dissimilarities
in timbre
betweenpairsof successive
toneswereevaluated.From thesedifferences,
integrated
differences
fordifferent
versions
ofthewholemelodyarecalculated,anddifferences
between
versions.
The possibility
of identifying
a
certainplayer,atcertaininstrument
ora certainmicrophone
position
may
begivenasrelativenumbers.
Thedissimilarity
dataareusedforthesynthesisof newversions
of the melodywith a rangeof nonuniformity
in
timbre.In thesecond
listening
test,acceptability
of nonuniformity
were
evaluated.
To studythedimensions
andphysical
variabilities
oftimbreby
sustained
tones,multidimensional
analysisof the subjective
differences
areperformed
andseveral
spectral
variables
fordescribing
thedifferences
are tested.
11:20
GGI0. Spectralcharacteristicsof the Helmholtz resonatordrivenby an
air jet. Roset Khosropourand Peter Millet (Department of Physics,
HamiltonCollege,Clinton,NY 13323)
Motivatedby an interestin theactionof airjetson resonantsystemsin
woodwinds,
preliminarymeasurements
havebeenmadeon thefrequency
spectraof severalair jet driven Helmholtz resonators.Over the rangeof
air jet velocitiesexamined,stableoscillations
dominatedby a singlefrequency (under certain conditionsharmonicsare in evidence)occur in
severalintervalsof jet velocity.Within eachsuchintervalthe dominant
frequencyincreases
with increasing
jet velocity.The spanof frequencies
associated
witheachintervalincludes
thecalculated
Helmholtzfrequency and,dependingon the resonatorand the interval,canbeasmuchasan
octave.The spectrumof thezonebetweentheintervalsis formedfroman
overlapof the extrapolatedspectraof the adjacentintervals,i.e., it is
markedby the appearanceof two frequencies,
whereone is abovethe
maximumfrequencyfrom the lower interval and the other is below the
minimumfrequencyfrom the higherinterval.
10:50
11:35
GGS. Theoreticalrelationshipbetweenbow pressureand vibration
amplitude,derivedfrom a sticking-slidingforce-velocitycharacteristic.
Xavier Boutilion and GabrielWeinreich (Randall Laboratoryof
Physics,Universityof Michigan,Ann Arbor, MI 48109)
GGI1. Acousticalbehaviorof a bass drum. Thomas D. Rossirig
The Helmholtzmotionfor bowedstringsmaybedescribed
with the
helpof a characteristic
between
thebow'sfrictionalforceandthestring
two largemembranes
may be set to equaltension,but moreoftenthe
batterheadis tunedto a highertension.The soundspectrumcontains
velocityat the bowingpoint. Althoughthis characteristichasneverbeen
many peaksthat canberelatedto the vibrationmodesof a membrane.The
dependably
measured,
someof its featuresareimpliedby players'commonexperience:.
In general,the vibrationamplitudechangeswith bow
pressure
orbowvelocity.Therelationships
between
thesechanges
andthe
lowtensionof theheadsplusthestrongcouplingvia theenclosed
air lead
(Department of Physics, Northern Illinois University, DeKalb, IL
60115)
The bass drum is one of the loudest instruments in the orchestra. Its
to a largefrequency
difference
(about1«octave}betweenthetwo (01)
local evolution of the characteristic will be establishedand discussed.The
modesassociatedwith in-phaseand out-of-phasemotion of the heads.
Sounddecayratesfor mostmodesareslightlygreaterwhenthetwo heads
caseofperfectstickiness,
in whichtheamplitude
becomes
independent
of
are at the same tension.
S69
J.Acoust.
Soc.Am.Suppl.1,Vol.82,Fall1987
114thMeeting:
Acoustical
Society
ofAmerica
S69
THURSDAY
MORNING,
19 NOVEMBER
1987
UNIVERSITY LECTURE HALL, 8:30A.M. TO 12:00NOON
SessionHH. Psychologicaland PhysiologicalAcousticsVI: External Ear, Inner Ear, and
Cochlear Implants
William W. Clark, Chairman
CentralInstitutefor theDeaf, 818 S. Euclid,SaintLouis,Missouri63110
ContributedPapers
8:30
HHI.
Static and dynamic compliancesof the rat teetorial membrane
under in vh•o-like conditions. Glenn H. Frommet (DAMPA
A/S, 5690
Tommerup,Denmark)
Three-dimensional
solutions
for propagating
wavesin thefluid-filled
gapbetween
thetectorialmembrane(TM) andtheorganof Corti (OC)
areobtainedandincludedin an existinganalyticalmodelof thecochlea.
The three-dimensional
solutions
giveessentially
thesamecouplingbetweenTM and OC as that previouslyfound with two-dimensionalsolu-
Compliances
wereexaminedqualitativelyin 17 rat cochleas
prepared
minutesafter death.Forceswereappliedperpendicularlyto the membranebya 10-/tin-thick
microelectrode
thatcouldalsovibrate.Sinusoidal
displacements
were10-pmpeakto peak.White andstrobelight illuminationwasused [G. H. Frommet,ActaOto-Laryng.94, 451-460 { 1982} ].
Staticdepression
of the membraneat pointsbetweenthe spiralsulcusto
the outerhair cellsproducedan elongatedhollow,whilealmostcircular
depressions
werenotedin the lip region.Dynamiccharacteristics
were
frequencydependent.Under 60 Hz, depression
patternsweresimilarto
the static ease.However, at 200 Hz, the regionbetweenthe sulcusand
outer hair cellswasquite rigid and displacedat the iimbal attachment.
Local vibrationsof the membranein the lip regionand over the sulcus
were almost circular. The mechanical characteristics
correlate with ul-
trastructural studies.It is concludedthat static analysesalone cannot
describe the viscoelastic behavior of the tectorial membrane.
tions.However,including
thethree-dimensional
solutions
givesriseto a
newpropagating
mode.With two-dimensional
wavesin thegap,themodel exhibits
threeducts(twosealee
andtheinnersulcus)andtwopropagatingmodes.
With three-dimensional
solutions,
thegapfunctions
asa
fourthduct.Consequently,
a thirdpropagating
modeappears.
The flow
patterns
associated
withthismodearedescribed,
andthemode'ssignificanceis discussed
[Work supportedby NSF.]
9:15
HH4. Quantificationof cerebrospinal
fluid(CSF)contamination
of scala
tympani (ST) perilymph samples. Akira Hara, Alec N. Salt,
Jogy Varghese, and RuedigerThalmaon (Department
Otolaryngology,
Washin.
gtonUniversity,
SaintLouis,MO 63110)
of
Previouslyit hasbeenreportedthatlevelsof mostaminoacidsin small
perilymphsamples( < 100nL) takenfromST throughtheroundwindow
(RW) ofguineapigsaredistinctlydifferentfromthosein CSF [A. N. Salt
8:45
andR. Thaimann,Adv.Otorhinolaryngol.
(in press)]. Thecomposition
HH2. Stiffnessof the tectorialmembrane
in liveMongoliangerbils.J.
of samples
of largervolumemorecloselyresembles
CSF. Now an analysis
of aminoacidcontenthasbeenperformedas the samplevolumewith-
J. Zwislocki,
M. W. Serafini,
andL. K. Cefaratti{Institute
forSensory
drawnthroughtheRW wassystematically
variedfrom 100nL to 5
Research,
Syracuse
University,Syracuse,
NY 13244-5290)
G!ycine, serine, glutamine, and alaninc were measuredby HPLC
{Physiological
Pico-Tag,Waters}.Up to 200 nL, the glyeinecontentof
ST perilymphwassimilarto that of scalavestibuli.With largervolumes,
theglyeinecontentrapidlydeclinedtowardthatof CSF.Thesedatasuggestthat perilymphsamplestaken throughthe RW are contaminated
with CSF if morethan200 nL is withdrawn.If ST perilymphis sampled
The classicalmodel of hair-cell stimulation in the mammalian cochlea, accordingto which the tcetorialmembraneactsas a stiff anchorfor
the cells'sterocilia,requiresthe stiffness
of the membranein the radial
cochleardirectionto be greaterthanthat of thesterocilia.This stiffness
wasmeasured
bymeans
offlexible,
calibrated
micropipettes
inserted
deep
intothemembrane
at thelocation
oftheouterhaircells.Theywereintroducedintothecochleathroughan openingin thelateralwallof thescala
media,asdescribed
previously
[J.J.Zwislocki,S.C. Chamberlain,
andN.
B.Slepecki,
J.Acoust.Soc.Am. Suppl.181,S6 (1987) ]. Thestiffness
was
determined
bymoving
themicropipettes
radiallyandbymeasuring
their
througha smallfenestra
inthethirdturn,largervolumes
(upto2/•L) can
bewithdrawnwithoutsignificant
CSF contamination,
evidentlybecause
of the distancefrom the cochlearaqueduct.The data alsosuggestthat
glyeinecontentcan be usedas an indicatorof CSF contaminationof ST
perilymphsamples.
bendand the resultingdisplacement
of the tectorialmembrane.According to the experiments,the radial stiffnessof the tectorialmembraneis
severaltimessmallerthanthe corresponding
stiffness
of the stereocilia
determined
by StrelioffandFlock(HearingRes.15, 19-28). Thiscontradiets the classical model of cochlear hair-cell stimulation. The tectorial
membraneappearsto act on the stereociliaasa massload rather than their
stiff anchor.
9:00
HH3. Three-dimensional
analysisof fluid flow betweenthe teetorial
membrane
andtheorganof Corti.Joseph
A.M. Boulet(Departmentof
Engineering
Science
andMechanics,
University
ofTennessee,
Knoxville,
TN 37996-2030)and J. BarneyHolt (SpaceTransportation
Systems
Division,RockwellInternational,$$5 DiscoveryDrive, Huntsville,AL
358O6)
S70
J. Acoust.
Soc.Am.Suppl.1,Vol.82,Fall1987
9:30
HHS. Two-microphonemeasurementof the power-refleetioncoefficient
in humanears. William J. Murphy, Arnold Tubis (Departmentof
Physics,Purdue University,West Lafayette,IN 47907), and Glenis
R. Long (Department of Audiology and SpeechSciences,Purdue
University,WestLafayette,IN 47907)
Foreachofeightnormalhearing
andeightabnormal
hearingsubjects,
the acousticintensityand powerreflectioncoefficient
spectraare measuredusinga two-microphone
probewithprobetips• 8 mmdownstream
from the pointof sounddelivery[W. $. Murphy, A. Tubis,and G. R.
Long, J. Acoust. Soe. Am. Suppl. I 81. S75 (1987)]. The tube oran
EtymoticResearch
ER-2 sounddeliverysystem
passes
throughoneport
and the probetipsfrom a pair of ER-7 microphones
passthroughthe
secondport of a latexear mold.Resultsin the frequencyrangeof 4-12
114thMeeting:
Acoustical
Society
ofAmerica
S70
kHz are compared
with previous
measurements
by Stinsonet al. [J.
Acoust.Soc.Am. 72,766-773(1982)], Hudde[J. Acoust.Soc.Am. 73,
The characteristic
equationfor a simplemodelof the externalear is
usedto demonstrate
theindividualeffectsof theradiationimpedance,
of
242-247(1983)], andStinson
[J.Acoust.
Soc.Am.77,386-393( 1985);
thepinna,andof theearcanal,including
a wedge-shaped
termination
at
79, 1003-1009(1986)]. Hearingthresholds
arealsodetermined
in order
the tympanicmembrane,
on the resonance
frequencies
of the ear.The
toidentify
anysignificant
correlations
intheobjective
andpsychophysical resultsshowthat a denotationsuchas "first quarterwaveresonance,"
measure.
[Worksupported
bya grantfromtheDeafness
Research
Founsuggesting
a physical
dimension
oftheear,whichisa quarterwavelength
dation.]
long at the resonance
frequency,is a misnomer.[Work supportedby
NIH, NINCDS. ]
9:45
HH6. The relationbetweenthe impedance
at the microphone
and the
transferimpedance
of an occludedear simalator.GeorgeF. Kuhn
(VibrasoundResearchCorporation, 2855 West Oxford Avenue,
10:15
Englewood,CO 80110)
TheANSI $3.25-1979
Standard
foranoccluded
earsimulator
specifiesthetransferimpedance,
thatistheratioof thepressure
at themeasuring microphoneto the volumevelocity12.7 mm in front of the micro-
phone,
from100-10000Hz. Thispaperpresents
analytical
relationships
between
thetransferimpedance
andthesimulated
eardrumimpedance.
Limitof errorcalculations
areusedto derivetheexpected
tolerances
for
oneimpedance
whenthetolerances
arespecified
fortheotherimpedance.
[Work support• by NIH, NINCDS. ]
HHS. Absorption,phase velocities,characteristlcimpedancesand
transmission
matricesfor tubesof smalldiameter.GeorgeF. Kuhn
(Vibrasound ResearchCorporation, 2855 West Oxford Avenue,
Englewood,CO 80110)
Numericalresultsfor theabsorption,
thephasevelocities,
thecharacteristicimpedances
andthetransmission
matrices,
relatinginputpressure
andvelocityto outputpressure
andvelocity,arepresented
for tubeswith
smallradii relativeto the boundarylayerthickness.Theseexactresults
are comparedto resultsbasedon other approximateanalyticalmodels
andtheirrangeof validityin termsof frequency
andtuberadiusisexam-
ined.Theexactanalytical
modelyieldselectroacoustic
analogs,
forcer-
10:00
HH7. Longitudinal resonancesof the human, external ear: A first
approximation.GeorgeF. Kuhn (VibrasoundResearchCorporation,
2855 WestOxfordAvenue,Englewood,CO 80110)
tain sizesand frequencies,
whichcontainnonrealizable
negativeresistances.
It isshownthata change
in thelengthof thetube(s)comprising
thetransmission
lineovercomes
thisdifficulty.[ Worksupported
byHIH,
NINCDS. ]
10:30-10:45
Break
10:45
HH9. A receptor-codedcochlearimp]ant: Speechdiscriminationand
comprehensionresults. Gerald S. Wasserman (Department of
Psychological
Sciences,
PurdueUniversity,W. Lafayette,IN 47907) and
Richard T. Miyamoto (Department of Oto]aryngo]ogy,Indiana
UniversityMedicalSchool,Indianapolis,IN 46202)
Cochlearimplantsare,amongotherthings,artificialreceptors.
Like
haircells,theytransduce
acousticenergyintobioelcctricsignalsthatactivateauditorynervefibers.Thecontribution
of receptorcodingto perception in adult andjuveniledeaf patientssurgicallyfitted with cochlear
implantshas thereforebeeninvestigated.
A filter-feedback
systemwas
usedto simulatethesignalprocessing
of naturalreceptors.
Thissystem
permittedcontrolled
within-patient
testsof theeffectof receptorcoding
on speechperception;
thiseffectwasexaminedin two differentways:
Speechdiscrimination
wastestedwith CVC monosyllables
that differed
only in their final phoneme.Speechcomprehension
wastestedwith a
modification of the SPIN test. All testswere run as two-alternative forced-
choicetasks.Patientswerecompletelyalonein a windowless
acoustic
boothduringtesting;
stimulation
anddatacollection
wereundercomputer control.In everycase,receptorcodingproduceda significant
improvementin phonemediscrimination.
The sentence
comprehension
taskwas
moredifficultandmostpatientswereat or nearchancein bothexperimental andcontrolvonditions;
however,receptorcodingcanproduceclearly
Hearing Laboratoryof the South,ENT Department,LSUMC, New
Orleans,LA 70112),andCedricF. Walker (Departmentof Biomedical
Engineering,
TulaneUniversity,New Orleans,LA 70118)
TheNucleusWSP-III isa speech
processor
forcochlearimplantsthat
stimulatestwo electrodes
per fundamentalperiod.The electrodes
stimulatedare chosenbasedon the first two formantfrequencies:
lowerfrequencyformantsexciteelectrodes
thataremoreapical.Thisgivesusersa
cueto discriminate
vowelswithdifferentformants.But,if twoparticular
vowelshad secondformantscloseenoughto fall within the frequency
band of some electrode, the user would miss that cue--those two vowels
would "behave"asif they had exactlythe samesecondformant. Cochlear
implantusersweretestedunderthreefrequency-to-electrode
maps:the
standardmap (usedby mostNucleusimplantpatients),the modified
standardmap (proposedby P. Blarney,privatecommunication,1987)
anda newmapdesignedto maximizecontrastbetweendifferentvowels.A
discrimination
testwasusedwheresubjects
werenotaskedto identifythe
soundsthey heard,but only to indicatewhetherthe differentword in a set
of threewasin theinitialor finalposition.Thistendsto minimizelearning
effects
dueto priorexperience
witha givenmap.Also,if cochlearimplant
userscan discriminatedifferent phonemes,they could conceivablybe
trained to identify them correctly, whereaslack of discrimination makes
identification
impossible.
[Work supported
byCochlearCorp.andSigma
Xi.]
significant
performance
in a patientwhosecontrolsentence
comprehension is at chance.
11:0o
11:15
HHlO. Vowel discriminationusing different frequency-to-electrode
mapsin cochlearimplantusers.Mario A. Svirsky(KresgeHearing
Laboratoryof theSouth,ENT Department,LSUMC, New Orleans,LA
70112andDepartmentof Biomedical
Engineering,
TulaneUniversity,
HHII. Evaluationof a multichannelcochlearimplant. Sigfrid D. Soli,
VirginiaM. Kirby, ChristophervandenHonert,andGregoryP. Widin
(Hearing ResearchLaboratory,270-4S-11,3M Center,Saint Paul, MN
NcwOrlcans,
LA70118),JohnK.Cu!len,HowardP.Ragland(Kresge
55144)
S71
J. A,coust.
Soc.Am.Suppl.1, Vol.82, Fall1987
114thMeeting:Acoustical
Societyof America
S71
A wearablemultichannelsignalprocessor
for stimulationof single-
electrode
cochlear
implants
hasbeenfieldtested
withtwopatients.
Each
channelin theprocessor,
whichisimplemented
in a digitalsignalprocessingchip,consists
ofa resonator
followedbyaninstantaneous
compressive
nonlinearity.The channeloutputsaredigitallymixedfor usewith singleelectrode
implants.The resonators
performa spectral-to-temporal
transformationof the inputsignalandthenonlinearities
limit outputlevelto
emulatethe responsecharacteristics
of normal auditoryneurons.The
resonator
andnonlinearity
parameters
areadjustedtoaccommodate
both
theacousticpropertiesof speechsoundsandtheelectricaldynamicrange
of the patient.Severalprocessor
configurations
with differentresonator
andnonlinearity
designs
havebeenevaluated.
The resultsof psychophysicaltests,usedto fit eachprocessor
configuration
to thepatientandmeasurespeech
performance
in quietandnoisewith eachconfiguration,
will
be reported.
taneousmaskingphenomena
to VllIth nerveor higherneuralmechanisms.[Work supportedby NIH.]
11:45
HH13.
Chinreel interactions measured by forward-masked "place"
tuning curves with multichannel electrical stimulation. Virginia
M. Kirby (Hearing ResearchLaboratory,270-4S-11,3M Center,Saint
Paul, MN 55144), David A. Nelson (Hearing ResearchLaboratory,
Universityof Minnesota,Minneapolis,MN 55455), Sigfrid D. Soli
(Hearing ResearchLaboratory,270-4S-I1, 3M Center,SaintPaul, MN
55144), and Todd W. Fortune (Hearing Research Laboratory,
Universityof Minnesota,Minneapolis,MN 55455)
Simultaneous
11:30
HHI2. Backward and forward maskingfor direct electrical stimulation
of the VIIIth nervein two profoundlydeaf subjects.L. J. Dent and B.
S. Townshand(Stanford ElectronicsLaboratories,Stanford,CA94305)
Two profoundlydeafmultielectrodeimplantsubjectswererequiredto
detecta probesignal( 10 msin duration) in a temporalgapbetweentwo
pulse-trainmaskers(each300msin duration).The detectionthreshold
wasmeasuredfor a probecenteredtemporallyin the gap,aswell asfor a
probeoffsetfrom centerby up to 97.5%. Also presentedwerethe pure
backwardand pureforwardmaskingcases.Qualitatively,bothsubject's
forward and backwardmaskingfunctionsapproximatedthoseobserved
for normalhearingsubjects[L.L. Elliott,J. Acoust.Soc.Am. 34, 11161117 (1962)] in that forward maskingdecayedmore graduallythan
backwardmaskingas a functionof probe-maskerseparation.Because
mechanical(cochlear)contributions
to masking[H. Duifhuis,J. Acoust.
stimulation
of multichannel
intracochlear
electrodes
cangiveriscto peripheralandcentralchannelinteractions.
The abilityto
eliminateor predictand controlthe interactionsproducedby a given
electrode
geometry
isa processing
goalforoptimizingperformance
witha
multichannelcochlearimplant.Previousstudieshaveusedloudness
summationand forward-maskingpatterntechniquesto estimateinteractions
betweenchannelsof electricalstimulation.In this study,interactionsbe-
tweenbipolarchannelsof analogelectricalstimulationwereestimated
using a forward-maskingparadigmwith a fixed-level,fixed-location
probe.By varyingthe electrodelocationof a 200-Hz, 300-mssinusoidal
maskeranddeterminingthelevelof themaskerat eachlocationnecessary
to just maska 200-Hz, 10-msprobe,a "place"tuningcurvewasderived.
The levelofmaskerrequiredat a givenlocationto maskthe probedepends
Soc. Am. 54, 1471-1488 (1973) ] can be excludedin the caseof direct
on the amountof excitationproducedby the probeandreflects,in part,
the degreeto whichthereis overlapof neuralpopulations
responding
to
eachstimulus.
These"place"tuningcurves,whichdisplayinteractions
as
a functionofmaskerlocationweredeterminedfor severalprobelevelsand
probelocations.Resultsand implications
for speechprocessing
strategies
VIIIth nervestimulation,thesedatasupporttheattributionof nonsimul-
will be discussed.
THURSDAY
MORNING,
19 NOVEMBER
UMS 4 AND 5, 8:30 A.M. TO 12:00 NOON
1987
SessionII. UnderwaterAcousticsVI. SignalProcessingfor UnderwaterAcoustics(Prrcis-PosterSession}
Thomas G. Muir, Chairman
NATO S•4CL•NT Centre,La Spezia,Italy
Chairman's
introduction---8:30
ContributedPapers
Followingpresentation
of the prrcis,posterswill be on displayuntil 12:00Noon.
8:35
111. Nonorthogonality of measured normal modes in shallow water.
Grayson H. Rayborn (Naval Ocean Research and Development
Activity, NSTL, MS 39529-5004 and Department of Physics and
Astronomy,Universityof SouthernMississippi,Hattiesburg,MS 39406),
GeorgeE. Ioup, and JulietteW. Ioup (NORDA, NSTL, MS 39529 and
Department of Physics and Geophysical Research Laboratory,
University of New Orleans,New Orleans,LA 70148)
The importance
of surmounting
the nonorthogonality
of measured
normalmodesandprocessing
shallow-water
datain sucha waythatmod$72
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall 1987
al compositions
areeffectively
recovered
for matchedfieldprocessing
has
beendemonstrated
by severalinvestigators.
The potentialfor improvementusingthistechnique
is greatest
whenthe nonorthogonality
of the
measured
modesislargest.Theamountbywhichthenormalmodesfail to
beorthogonal
fora varietyofoceanbottoms,
arraylengths
anddiseretizations,andarraypositions
for the Pekerismodelhasbeenstudied.Environmentsare selectedto reflectsedimenttypescharacteristicof the continentalshelf.It hasbeenfoundthat the nonorthogonality
is greatestfor
waterdepthsandfrequencies
at andjustabovemodalonsets,
for soundspeedratioscloseto 1, and for arrayswhichspanonly a fractionof the
watercolumn.Judicious
placement
andlengthselection
for shortarrays,
however,
cangiveorthogonal
measured
modes
forsomecombinations
of
frequencies
andenvironments
whena smallnumberofmodes
arepresent.
114thMeeting:AcousticalSocietyof America
$72
8:39
I12. Effects of measuredmode nonorthogonalityon conventional
matchedfield proeessing.
JulietteW. Ioup, GeorgeE. Ioup (Naval
OceanResearchand DevelopmentActivity, NSTL, MS 39529-5004and
Departmentof Physics,Universityof New Orleans,New Orleans,LA
7014g), Grayson H. Rayborn (NORDA, NSTL, MS 39529 and
Department of Physics and Astronomy, University of Southern
Mississippi,
Hattiesburg,MS 39406), DonaldR. Dei Balzo(NORDA,
NSTL, MS 39529), andChristopherFeuillade(ODSI DefenseSystems,
peaks.Thispossibility
of loweringtherequirements
onourknowledge
of
theenvironment
is investigated
with two methods:( 1) by constructing
multiplebeam(constraint)algorithms
and(2) byconsidering
stochastic
blurringbythemedium.Thesetwoapproaches
areappliedto plane-wave
beamforming
andmatchedfieldprocessing.
8:51
Inc., 6110 Executive Boulevard, Suite 320, Rockville, MD 20852)
As discussed
by Raybornet al. {precedingabstract),the potential
improvementachievable
from the useof modalfilteringin matchedfield
processing
is greatest
whenthemeasured
modesareleastorthogonal.
To
assess
the abilityof matchedfieldprocessing
usinga conventional
crosscorrelationestimatorto realize this potential,ambiguitysurfacesfor a
Pekeriswaveguidehave beenconstructedemploying(a) the pressure
fieldsat the hydrophones
and (b) the amplitudesresultingfrom modal
filtering.Thequalityof thesurfaces
isquantified
utilizingmeasures
that
comparetheheightof thesourcepeakabovethemeanandtheheightof
the sourcepeakabovethe standarddeviationof the surface.The results
indicatethat modalfilter processing,
for a givenarray of hydrophones,
offersthe mostimprovementwhen bottomdepth,bottom type, and frequencycombineto producemeasured
modesthat arethe leastorthogo-
nal,andyieldsno improvement
whenthemeasured
modesareorthogonal.
IIS.
Spatial
matched processing for
multipath propagation.
Matthew Dzieciuchand T. G. Birdsall (Communieationand Signal
ProcessingLaboratory,4242 œœCSBuilding, Departmentof Electrical
Engineeringand ComputerScience,The Universityof Michigan,Ann
Arbor, MI 48104)
Underwateracousticpropagationis characterizedby multipathor
multimodepropagation.Ray theoryand modethenryare not fully adequatefor modelingphysicalreality.Impulseresponses
canbemoreaccuratelycalculatedusingGaussianbeamtheory.Signalprocessors
can be
designed
to takeadvantage
of thechannelcomplexity
if thepropagation
is
actuallyknownsothatdetectability
isincreased.
The proposed
technique,
channelmatchedfiltering,synthetically
backpropagates
thewavefrontto
a hypothesized
sourcelocation.Accuratepassive
estimates
of sourcelocation can be madewithout knowledgeof the signalcharacteristics.
GB
theorycan easilyaccommodate
a range-dependent
deepwaterenvironment. [This researchsupportedby theOfficeof Naval Research.
]
8:43
II3. Effects of correlatednoiseon the cross-spectralmatrix in modal
8:55
composition
space.GeorgeB. Smith, ChristopherFeuillade (ODSI
Defense Systems,Inc., 6110 Executive Boulevard, Rockville, MD
20852), and Donald R. Del Balzo (Naval Ocean Research and
Development
Activity,Code244,NSTL, MS 39529-5004)
Computersimulationsof hydrophonecross-spectral
matricesin a
shallow-waterwaveguideweregeneratedfor signalswith differentmixturesof,correlatedandwhitenoise.Thesematriceswerethenmappedto
modalcomposition
space,a spacepopulatedby vectorswhoseelements
are the amplitudesfor the trappedmodes.It wasfoundthat, in modal
compositionspace,the cross-spectral
matrix is not sensitiveto the differencebetweencorrelated and white noise,but is sensitiveto the difference
betweennoiseandsignal.While thedistributionof signalandwhitenoise
amongtheelements
of thecross-spectral
matrixissimilarbeforeandafter
the mappingto modalcomposition
space,the distributionof correlated
andwhitenoiseisnot.Temporallydiscretenoisesources,
whicharecorrelatedat thehydrophones,
butnotfromsampleto sample,makelittleor no
contributionto the off-diagonalelementsof the cross-spectral
matrix in
modal compositionspace.This fact has significantimplicationsfor
matchedfieldprocessing
in low signal-to-noise
situations.
lI&. A new techniqueof acousticmodefilteringin shallowsea.Harish
M. Chouhan and G. V. Artand (Department of Electrical
Communication
Engineering,
IndianInstituteof Science,
Bangalore
560
012, India)
A newtechniqueof filteringacousticnormalmodes,whichovercomes
manyofthedrawbacks
oftheearliertechniques,
ispresented
in thispaper.
It is basedon the fact that eachnormalmodein an isovelocitychannel
comprises
a pairofplanewaveswithcharacteristic
directions
of propagationsymmetrically
disposed
with respectto thechannelaxis.A vertical
array of equispaced
hydrophones
is shadedso as to steer nullsin the
directionalresponse
of the arrayalongthe directions
of arrivalof plane
wavescorresponding
to theunwantedmodes.All theshadingcoefficients
arereal,leadingto simplicityin thehardwarerealization
of theprocessor.
Theshading
coefficients
areinvarianttoa shiftin thepositionofthearray.
Thearrayneednotspantheentiredepthof theocean.Efficient
filteringis
possible
evenwhenthe eigenfunctions
of the modeshavea significant
penetration
into thebottom.[Work supported
by DOE, Government
of
India. ]
8.-47
8:59
I14. Adaptive beamformingor matchedfield processingin media with
uncertain propagation conditions. A. B. Baggeroer, H. Schmidt
(Massachusetts
Institute of Technology,Cambridge,MA 02139), W.
117.Matched eatastrophealeconvolution
with applicationto the inversion
ofmarineseismicrefraefiondata. Michael G. Brown (RosenstielSchool
A. Kuperman(Naval ResearchLaboratory,Washington,DC 20375},
andE. K. Scheer(WoodsHole Oceanographic
Institute,WoodsHole,
of Marine and AtmosphericScience,University of Miami, 4600
RickeobackerCauseway,Miami, FL 33149) and Paul E. Bullwinkel
MA 02543 )
(Applied MeasurementSystems,Inc., 1415 S.W. 21st Avenue, Fort
Adaptivebeamforming
or matchedfieldprocessing
provides
highresolutionwith sidelobe
controlif accuratereplicafieldscanb• generated.
The generation
of thesereplicafieldsis a formidable
problemrequiring
knowledgeof the complexoceanpropagationenvironment.On the other
hand,thedetectionproblemin theoceanmaynotrequirehighresolution,
whereassidelobecontrol is still an important issue.Relaxingresolution
requir•nentssuggest
that a certaintoleranceincorporatinguncertaintyof
the propagationconditionsispermissible,or evendesirable,becauseof the
difficulties
bothin specifying
themediumexactlyandin identifying
global
$73
J. Acoust.Soc.Am.Suppl.1, VoL82, Fall 1987
Lauderdale, FL 33312)
The problemof extractingaccurateestimatesof the travel timesof
unresolved
arrivals(e.g., the secondand third arrivalswithin a triplication ) from a set of noisy bandlimited measurementsof a time-dependent
acousticwavefieldisaddressed.
The methodof solutionpresented
isbased
on the assumption
that the underlyingcausticstructure(or, equivalently,
the traveltime curvestructure)of the wavefieldis known.Because
genetic causticsassociated
with causalwavefieldstakeon only certainforms,
thisis a weakassumption.
Additionally,it is assumed
that the medium
114thMeeting:Acoustical
Societyof America
S73
structurevariesasa functionof depthonly.Thisfurtherrestrictstheclass
improvedby usingvariousprefiltering
techniques
to process
theexperi-
of observablecausticsections.Theseconstraintsare incorporatedinto a
mentaldata.Eachof the prefilters--Hannan-Thomson,
smoothed
coher~
encetransform,and phasetransform---consists
of a frequency-domain
weightingfunctionthat is appliedto thecross-spectral
densityfunction
beforethecross-correlation
functionis computedusingthe inverseFourier transform.The prefiitersare observedto enhancethe estimationof the
timedelayby reducingtheambiguityassociated
withdetectingthepeak
valueof thebasic(unweighted)cross-correlation
function,whichisoscil!story in nature.
matchedfield processing
approachto the deconvolution
problem.The
techniqueis demonstratedusinga measuredmarineseismicrefraction
dataset.A Herglotz-Wiechertinversionof the resultingkinematicdata
T(R ) agreeswell with previouslypublishedwaveforminversionsof the
samedataset.Advantages
of thenewapproach
overlinearizedwaveform
inversions are discussed.
9:03
9:15
IIg. Effects of nearby soft screens on idealized array reception.
Rudolph Martinez and Ann Westagard (Cambridge Acoustical
Associates,Inc., 54 CambridgeParkDrive, Cambridge,MA 02140)
Arraysof sensors
mustoftenfunctionin theneighborhood
of riffratting and reflectingsurfaces;these,in turn, representeffectivepassive
sourcesthat add to the incomingsignal.The resultis a computedwavenumberspectrumcontaminatedby the presenceof spurioustargetsin
whichthe true seasourcemay appearshiftedoff itsactualazimuth.Here,
sucheffectsare demonstratedfor the fully analyzablesituationof an unshadedarray neara thin semi-infinitesoftscreen,takeneither asa colinear
aft baffleor a perpendicularbackstopto the incidentwave. Exact and
asymptotic
expressions
havebeenderivedto predictperceived
strengths
of virtualtargetsandassociated
azimuthaldistorsions;
theirreportednumericalevaluations
couldserveasbenchmarkresultsagainstwhichone
mightgaugetheeffectiveness
of sophisticated
processing
methodsunder
similar array installationconditions.
9.'O7
II9. Limitationsto sourcedescriptionset by a finite recei 'ing aperture.
Philip L. Stocklin (Consultingphysicist,439 Blue Jay Lane, Satellite
Beach,FL 32937}, and Norma L. Stocklin(SystemsAnalyst, 439 Blue
Jay Lane, SatelliteBeach,FL 32937}
II11. SteppedFM signalsfor acousticremote sensingof geoaeoustic
properties of bottom sediments. Harry A. DeFerrari and Hien
B. Nguyen (Department of Applied Marine Physics,R.S.M.A.S.,
Universityof Miami, Miami, FL 33149)
Signalsusedfor sub-bottomprofilingare usuallyhigh-intensitytransientsgenerated
bycxplosious,
air guns,sparkers,
etc.Eachtransienthasa
uniquecomplexfrequencyspectrumand serialtransmissions
cannotbe
coherentlyaveraged.Coherentacousticsignalsgeneratedby electromechanicaltransducers
arenot widelyused,owingto the relativelylow intensityor bandwidthlimitations,but evenweaksignalscan be averaged
for longperiodsif thepropagation
mediumisstable,to produceveryhigh
equivalentsignallevels.Likewise,it appearspossibleto synthesizevery
broadband
signals
by coherently
averagingnarrow-band
signals.Several
narrow-bandsignalstransmittedseriallycanbeprocessed
asthoughthey
were transmittedsimultaneouslyto synthesizesignalsof any desired
bandwidth--amethodcalledsteppedFM. A systemhasbeendeveloped
andtestedfor transmittingandreceivingpseudorandom
codesteppedFM
signals.Signalswith a bandwidthof 1700Hz and intensitylevelsgreater
than 2 i0 dB after processing
are usedto probethe firstfew tensof meters
of thebottomsediments.
The resultingpulseduration,approximately
0.5
ms,allowsfor a separation
of reflectedfromrefractedpaths.Traveltimes
of refractedrays can then be usedfor tomographicinversionsto yield
compressional
velocityprofilesof the bottomsediments.
Spatialsamplingfunctiontheoryresultsare statedfor a monochromatic acoustic field and for a bandwidth-limited
resultsare appliedto a finitereceivingapertureto estimatethe physical
limitationsto sourcedescriptions
obtainable
fromtheoutputsofelements
of the aperture.Effectsof variationsin propagationconditions,received
signal bandwidth,receivedSNR, and available processingtime are
shown.Relationships
to inversefieldprocessing
are developed.
9:11
II10. Improvedtime delayestimatesof underwateracousticsignalsUS/he
beamforming
andprefilteringtechniques.
BrianG. Ferguson(Weapons
Systems Research Laboratory, Defence Science and Technology
Organization;Royal AustralianNavy ResearchLaboratory,P.O. Box
706, Darlinghurst2010, Australia)
The cross-correlation
methodfor estimatingthe differentialtime delay for an underwateracousticsignalto arrive at two spatJellyseparated
receiversis described.The output amplitudesof the two receiversare
crosscorrelatedand the lag time at which the cross-correlation
function
peaksprovidesan estimateof the time delay.Often the time delayestimatesof thesignalare corruptedby the presence
of noise.By replacing
each of the (omnidirectional) receiverswith an array of receiversand
thencrosscorrelatingthebeamformed
outputsof thearrays,it is shown
thattheeffectof noiseonthetimedelayestimationprocess
issubstantially
reduced.Bothconventional
and adaptivebeamformingmethodsare implementedand theadvantages
of arraybeamforming(prior to crosscorrelation)arehighlighted
usingbothmodeleddata( fortutorialpurposes)
andexperimental
data.The performance
of thecrosscotrelatoris further
S74
9:19
acoustic field. These
J.Acoust.
Soc.Am.Suppl.1,Vol.82,Fall1987
1112. Signal design for Doppler processing. Ziad Haddad and
BowenParkins(AT&T Bell Laboratories,14A420,WhippanyRoad,
Whippany,NJ 07981)
The Dopplersonarprocessing
requires
that theilluminaJting
signal
havea spectrumwithlow sidelobes
overtherangeof frequencies
at which
Dopplershiftsare expected.This is conventionallyachievedby "windowing" the driving sinewave.Uncertaintiesin the amplituderesponse
(thresholdonsetandlinearity) of typicaltransducers
makeit desirableto
havealternatemeansof obtaininglowsidelobes.
Oneapproachisto transmit a seriesofnonuniformlyspacedshortpulsesof constantdurationand
amplitude.Pulsestart timesare specifiedto yield the desiredspectral
shapeusingtheapproachofA. Ishimaru[ IEEE Trans.Ant. Propag.AP10, 691-702 (1962)] developedfor spacetaperingantennaarray elements.The resultingspectrumis not affectedby nonzerothresholdonset
or limitedlinearrange.The sidelobereductionthat can be achieved
pendsonthenumberof pulses,hence,ontheamplifierbandwidth.Amplitude shadingand varying pulsedurationsallow the de.signofa sec.
ond typ•
of signal,a windowedcw signalthat doesnot dependon thresholdonset
and is less sensitiveto amplifier bandwidth. The sidelobereduction
achievablewith this seconddesigndependson the linear range.
9:23
II13. Phaserecoveryand calibrationwith underwateracousticarrays.
Nathan Cohen(MetropolitanCollege,BostonUniversity,Boston,MA
02115)
Underwateracousticimagingprovidesuniquechallenges
because
of
the nature of the medium and difficulties in accurate measurement of
114thMeeting:
Acoustical
Society
ofAmerica
S74
arrayobservables.
Baseline
uncertainties
andlossof phaselockingmake
phaseobservables
especially
difficulttoacquireinsomecases.
Here,linear
and nonlinearimagingtechniques
that.aid in thecalibrationand/or recoveryof phaseobservables
andtheself-calibration
ofamplitudeobservablesaredescribed.
Enhanced
dynamicrangeandimageaccuracy
arepossible with these post-processing
techniques,which include closure
relationsand phasereferencing.
Examplesof theapplicationof the techniquesin otherimagingdisciplines,
suchasopticsand radio astronomy,
are discussed.
9:27
II14. Interpretation of coherenceestimatesdetermined for time seriesof
limited length. Allen E. Leybournc,III (Department of Engineering
Technology,University of SouthernMississippi,Box 5172 S. Station,
Hattiesburg,MS 39406-5172)
the calculationof the reverberation
andnoisebackgroundalongwith the
signalpropagation
characteristics.
To consider
thegeneralcaseofa threedimensional
beampatternfor bothsourceandreceiver,andthreedimensionalnoisefields,thepredictionmodeltendsto beexpensive
in computer
time and memory requirements.The ASONAR model presentedhere
incorporates
theRUMBLE bistaticreverberation
model[ H. P. Bucker,J.
Acoust.Soc.Am. Supp.1 80, S 63 (1986) ] and the DUNES directional
noisemodel[ R. W. Bannister,A. S.Burgess,
andD. J. Kewley,J. Acoust.
Soc.Am. Suppl.I 80, S65 (1986) ]. Thesenewlydeveloped
modelsincorporatefast executionspeedsand can run on IBM PC type microcomputers.By usingSALT (_Sound-A_
ngle-_Level-Time)
tables,the propagation lossand reverberationto the many scatteringareasare quickly
determined.The scatteringareasare increasedin sizeas the rangesincreaseto keepthe computationtime within reasonable
limits.The noise
calculationsare madeusingsimplifiedpropagationlaws.ASONAR combinesthe outputsof RUMBLE and DUNES to calculatebistaticsignal
excessversusrangefrom the receiver.Comparisonswith other models
andsomeexperimental
dataaremade.[ Work supportedby theNORDA
NOP Programand NUSC. ]
Coherenceof multichanneltime seriesdatahasbeencalculatedby the
methodof G. C. CarterandJ.F. Ferrie[A Coherence
andCross
Spectrum
EstimationProgram,Programsfor Digital SignalProcessing
( IEEEoNew
York•1979),No. 2.3-1-18]. The properties
of thisstatistichasbeencontrastedthroughsimulationstudiesat known noiselevelsfor shortand
longtime seriesthrougha rangeof 40 datasegments.
Resultsat lessthan
eightdatasegments
are shownto bedifficultto interpret;however,modestimprovementsin the coherenceestimatecanbe madeby adjustments
indicatedby thesestudies.A methodof calculatingcoherence
estimates
througha techniquereferredto as frequencybin averagingis described.
The results obtained are contrasted
with the conventional
method of
Carter. Although reliableestimationof coherencefor short time series
data (transient data) is difficult to obtain in the conventional sense,the
comparisons
madeshouldprovidea basisfor interpretationof coherence
estimates
aswell assuggest
corrections
that may be appliedto relatively
shorttime seriessequences.
[Work supportedby NORDA.]
9:31
II15. The effect of multipath and sensor location offsets on the
performanceof a cross-correlation
system.P. Bilazarian (Raytheon
Company, Submarine Signal Division, 1847 West Main Road,
9:39
II17. The designand performanceanalysisof barrel staveprojectors.D.
F. Jones and G. W. McMahon (Defence Research Establishment
Atlantic, P.O. Box 1012, Dartmouth, Nova Scotia B2Y 3Z7, Canada)
There is growing interest in low-frequency,light-weight sound
sourcesfor underwateracoustics
researchandfor potentialfuturesonar
applications.
A designbeingstudiedat DREA is the barrelstaveprojector, which consistsof a piezoceramic
cylinderdrivinga set of annular
staves in flexure. An electroelastic finite element model has been used to
analyzethelinearvibrationsandacousticradiationsof projectorshaving
outer diametersof about 8 cm and fundamentalresonance
frequencies
below 1600Hz in water. Prototypeprojectorsthat operateat electroacousticefficiencies
greaterthan 50% at resonancehavebeenassembled
andtheirmeasured
acoustic
properties
havebeencompared
to thosepredictedby the model.In addition,a brief discussion
of the modelparametersand limitationsis given.
Portsmouth, RI 02871 )
The combinedinfluenceof multipleray arrivalsandsensorlocation
offsetson the performanceof a broadbandcross-correlation
systemis
investigated.
Thesystem
consists
of threesensors
thatarenominallypositionedon a horizontalline. Sourcelocationparametersare determined
from time-delayestimates
obtainedby cross-correlation
techniques.
An
analyticalmodelfor the predictionof localizationbiaserrorsdueto multipathandto offsetsfrom nominalsensorpositionsisdiscussed.
This model
is applicableto an oceanicmediumwith a depth-dependent
sound-speed
profile.Resultsarepresented
for a varietyofmultipathconditions,
suchas
thoseassociated
with directpath,surfaceduct,bottombounce,and convergencezonetypesof propagation.The sensitivityof localizationerrors
to variationsin environmentalparameters,suchas seastateor bottomreflectionproperties,is also investigated.It is demonstratedthat multipath, especiallywhencombinedwith sensorpositionoffsets,can havea
significantimpacton systemperformance.
9:35
II16. A fast bistatlc reverberationand systemsmodel. D. J. Kewley
(Naval Underwater Systems Center, New London, CT 06320 and
WeaponsSystems
ResearchLaboratory,DSTO, Departmentof Defense,
GPO Box 2151, Adelaide, SA, Australia), and H. P. Bucker (Naval
OceanSystemsCenter,SanDiego, CA 92152)
The performance
predictionof bistaticactivesonarsystemsrequires
$75
J. Acoust.$oc. Am. Suppl. 1, Vol. 82, Fall 1987
9:43
I118. A practical VME-based sonarsystemdevelopmentworkstation.
Shon Sloat(AP Labs,4411MorenaBoulevard,Suite150,SanDiego,CA
92117)
Thispaperdescribes
presentcapabilityandfurturedevelopment
plans
of a practicallow-costsonarsystem-development
work stationbasedon
off-the-shelf
VME equipment.
The workstationallowssystemengineers
and algorithmdesigners
to quicklydevelopsonarprocessing
algorithms
andsystems.
The workstationcanbeusedto (a) simulateandanalyzethe
characteristics
of realtimeenvironments
for systemandalgorithmdevelopment,(b) concurrentlydevelopfinal implementation
software,and
(c) generate
analogtestdataforsystem
testandoperatorinstruction.
The
work stationovercomesmany of the difficultiesexperiencedwith developingsonaracousticsignalacquisitionand processingsystems:high
designandmaintenance
costsof customequipment;lackof controllable
testdata;inabilityto correlatesimulationdata with final systemperformance;andhighsoftwaredevelopment
costs,particularlywith parallel,
pipelinedsignalprocessing
equipment.The sonardevelopment
work station hardwareconsistsof a 16.67-MHz 68020 processorsupportedby a
VME busarchitecture.The hardwareprovides(a) internrivecolorgraphics, (b) Sky Warrior and Mecury Zip 3232 array processors.
The work
stationsoftwareis basedon the Unix development
system,VRTX real
time kernel,X-Windowsstandardcolorgraphicssoftware,andarray processorsonarprocessing
primitives.This foundationprovidessoftware
portabilityand deviceindependentgraphics.
114th Meeting:AcousticalSocietyof America
S75
THURSDAY
MORNING,
19 NOVEMBER
1987 TUTTLE
CENTER ROOM, 9:00 A.M. TO 12:05 P.M.
SessionJJ. Physical AcousticsV: Acousticand SeismicCouplingI: Air-Solid Interfaces
Gilles A. Daigle, Chairman
Divisionof Physics,National ResearchCouncil,Ottawa, OntarioK1,4 OR6, Canada
Cboirrnan's Introductions9:00
Invited Papers
9:05
JJ1. Near-groundsoundfieldsandsurfacesof finite impedsnee.
TonyF. W. EmbletonandGillesA. Daigle
(Divisionof Physics,NationalResearchCouncil,Ottawa,OntarioK 1A 0R6, Canada)
Studiesoverthe past30 yearshaveelucidatedthe effectsand interactionsof manymechanisms
involvedin
soundpropagation
outdoors.Interactions
with thegroundsurfaceareespecially
importantfor manyapplicationsto practicalproblems.It isparticularlysignificantthat groundsurfaces
areporous,and thushavea finite
complexacousticimpedance.
The historyof soundfieldmeasurements
to deducevaluesof impedance,
andits
directmeasurement,
is reviewed.Suchdata prompted,and werethen usedto validate,modelsfor ground
impedance,
firstin termsof a singleparameter(flowresistivity
of thegroundsurface)andlaterin termsof one
to threeadditionalparameters.
Impedancevaluesfor manygroundsat low frequencies
aredifficultto measure
accuratelyand severalnewtechniques
havebeendeveloped.Nonisotropicandnonhomogeneous
groundhas
beenmodeledasa layeredmediumor asa fluid-filledporousmatrix. Theseeffortshaveincreasedour understandingof the acousticalpropertiesof the groundasan air-solidinterfacefrom a purelyempiricalbasisto a
detailedphysicaldescription
basedon themicroscopic
properties
of theground.
9:35
JJ2. Airborne soundto seismiccoupling:Backgroundfor developmentof the models.JamesM. Sabatier,
Henry E. Bass,and Lee N. Bolen(PhysicalAcousticsResearchLaboratory,The Universityof Mississippi,
University,MS 38677)
The initial measurements
of the acoustic-to-seismic
couplingphenomenausingloud speakersas sound
sources
weremadeby the Universityof Mississippi
andWaterwaysExperimentStation.For thesemeasurements,a speakerwassuspended
froma crane,thesoundlevelin thefarfieldwasmeasured
with a microphone
abovethesurface,andthegeophone
response
wasmeasured
belowthesurface.The resultsof thisworklargely
indicatedthat the geophone
hada response
1000timesgreaterthanonewouldexpectfromcalculations
based
uponsimpleacoustictransmission
througha boundarybetweentwo perfectfluids.Anotherfindingwasthat
thetransittimesfromspeakerto microphone
andspeakerto geophone
wereapproximatelythespeedof sound
in theair. Success
in ourlabwithwater-saturated
sediments
suggested
theapplication
of theBlotmodelto the
ground.Microphonesweredeveloped
that wereusedasa porefluidprobein the soil,andthe attenuationand
phasespeedin the pore fluid were measured.This work led to the understandingof the commonlyassumed
locallyreactingpropertyof the ground.
10:05
JJ3. Airbornesoundto seismiccoupling:Presentunderstanding.
K. Attenborough(EngineeringMechanics
Discipline,The OpenUniversity,Milton KeynesMK7 6AA, UnitedKingdom) andJ. M. Sabatier(Physical
AcousticsResearchLaboratory,Universityof Mississippi,University,MS 38677)
Theoriesof outdoorsoundpropagation
at near-gra•ingincidenceon porousgroundsurfaces
assumeeither
that the groundsurfaceis an impedanceboundaryor that it is one of extendedreaction.Suchtheoriesare
consistent
with modelsof theacousticbehaviorof the groundasa locallyreactingfluidor asa semi-infinite
or
layeredmodifiedfluid supportinga singletype of compressionalwave motion. However, thesemodelsare
unableto explainthe responseof buriedgeophones
to airbornesoundsources.Measurementsof the ratio of a
shallowburied geophoneoutput to the output of a verticallyseparatedmicrophoneplacednear the ground
surfacehavebeenexplainedin a varietyof soil typesby meansof a layeredporoelasticgroundmodel.The
layeredporoelasticgroundmodeland its experimentalvalidationare described,and its implicationsfor the
impedance-frequency
characteristics
of outdoorgroundsurfaces
are explored.
S76
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
114thMeeting:Acoustical
Societyof America
S76
ContributedPapers
10•$
JJ4. Sefmnic,acoustic,andionospheric
wavekinematicsassociated
with
moderateto large earthquakes,S. I. Warshaw, F. E. Followill
(LawrenceLivermoreNational Laboratory,Livermore,CA 94550), J.
M. Mills, Jr. (SOHIO Production,Dallas, TX 75221), and P. R. Albec
(Radio Sciences
and Instrumentation,SantaFe, NM 87501)
UnusuallydetailedDopplerradarrecords
ofionospheric
disturbances
followingtwo moderate-to-large
dip-slipearthquakeswere reportedin
1984.Theseindicatethat earthquakes
can perturbthe ionosphere
by
meansof acousticwaveslaunchedby the movinggroundsurface.For one
arrivals,sincethey travel at the higherseismicwavevelocity,but their
amplitudesareaboutthreeordersof magnitudelessthanthemotioncou-
pledviathelater-arriving
air wave.A comparison
of thesummerandthe
winterrecordings
showstwomajoreffects
of a 25-cm-thick
snowcover.
Frequencies
above100Hz arestronglyattenuated,with signalsrecorded
by geephones
aboveandbelowthe snowyieldinga valueof around2 for
the Q of snowat 30 Hz; the snowproducesa strongwaveguideeffectthat
enhances
theair-coupled
Rayleighwaves.[Work supported
by Directorateof ResearchandDevelopment,U.S. Army corpsof Engineers
Project
4A762730AT42. ]
earthquake
{magnitude
6.5,Coalinga,
CA, 2 May1983[I. H. Wolcottet
aL,J. Gcophys.
Res.89, 6835-6839
(1984)]},a seismic-aeroacousticionospheric
kinematicwaveanalysis
wasperformed
to explainradarsignaturetiming.SurfaceRayleighwavesweremodeledand interpolated
frommainandafter-shockseismicrecords,acousticwavetrajectories
by
acousticray tracingin a standardatmosphere
wereestablished,
andradar
detectionaltitudesweredeterminedfrom radio rays tracedthroughan
ionosphere
calculatedfroman ionogrammeasured
closeby.Our calculated resultsagreewellwith Dopplersignature
timesobserved
onseveral5and 10-Ml-Izradarbeampaths160-300km fromtheepicenter.
Similari-
tiesanddifferences
wereidentified
in theotherearthquake
{magnitude
7.1,Urakawa-Oki,
Japan,21March1982[T. TanakaetaL,1.Arm.Terr.
Phys.46, 233-245(1984)]} andits signatures
werestudied
to assess
commonalities
in perturbationmechanisms.
It is tentativelyproposed
thatnonlinearacoustic
propagation
effects
couldbesignificant
in shaping
observed
Dopplersignatures.[Work performedunderthe auspices
of
USDOE by LLNL undercontractW-7405-Eng-48.
]
11:20
JJ7. Applicationof ray theory to propagationof low-frequencynoise
from wind turbines. James A. Hawkins and David T. Blackstock
( AppliedResearch
Laboratories,
TheUniversityofTexasat Austin,P.O.
Box 8029, Austin, TX 78713-8029)
Raytheoryhasbeenusedtoattempttoexplainthepropagation
ofvery
low-frequency
( 1-20 Hz) noisegenerated
by downwindwindturbines.
Two NASA fieldexperiments
with a largedownwindmachineat MedicineBow,Wyoming,showthatthedownwind
sounddecays
by spherical
spreading
nearthesource,
butbycylindrical
spreading
downrange.
Ray
theorycalculations
explainthisbehavior.The favorablewindgradient
downwindcauses
raysto refractdownwardandbouncealongtheground.
A soundchannelis built up by repeated
jumpsin the numberof ray
arrivalsat the receiverasdownwindrangeisincreased.
Near the source,
wherenomultiplyreflected
raysarrive,thesoundfieldspreads
spherical10:50
JJS. Acoustic-to-seismic coupling under winter conditions.
Lindarnae Peck (USACRREL, 72 Lyme Road, Hanover, NH 037551290)
ly. The firstjump (onsetof multiplearrivals)is predictedto occurat
about2 km for the conditionsof the NASA experiments.
The second
NASA experiment
confirmsthis prediction.For the upwindsound,a
shadowzoneis predictedbecause
of theunfavorable
windgradient.The
NASA measurements
showonly that the upwindSPL in the predicted
shadowzoneisof order7-! 5 dB lessthan thedownwindSPL at compara-
A fieldprogramto investigate
acoustic-to-seismic
couplingunder
winterconditionstook placein Maine duringDecember1985-January
bleranges.[Work supported
by NASA. ]
1986.The testareawaspackedsandwith a top layer (30 cm) of loose
sand.Site conditionswere: 20-cm frost with no snowcover, 6-cm snow or
18-cmsnow;and45-cmfrost,28-cmsnow.Microphoneswereat heights
of 1/2-2 m or at the sand{snow)surface.Geephones
wereplacedat the
snowsurface,the sandsurface,and severaldepthsin the sandlayer.
Acoustic-to-seismic
couplingthroughfrozensandwasinvestigated
under
controlledconditions
usinggeephones
in a sandbed
at the USACRREL
FrostEffectsResearchFacility.Testconditionswere:dry sand,frozenor
onfrozen;saturatedsand,frozen or unfrozen;and thawingsand.The
acousticsourcefor both investigations
wasblank pistolfire. Resultson
acoustic-to-seismic
couplingthrougha snowlayerand/orfrozensandare
presented
andcontrasted
withsummerconditions
for thefrequency
hand
5-500 Hz. [Work supported
by Directorateof Researchand Development,U.S. Army Corpsof EngineersProject4A762730AT42.]
11:05
JJ6. Low-frequencyaconstic-to-aeismie
couplingin the summerand
winter. Donald G. Albert (USACRREL, 72 Lyme Road, Hanover,NH
03755-1290)
Experiments
conducted
in northernVermontinvestigated
acousticto-seismic
couplingin the5- to 500-Hzfrequencybandfor rangesbetween
I and300m.Thestrongest
couplingintothegroundoccursastheair wave
passes,
witha measured
ratioof about0.001cms- •fPa.TheP waves
are
inducedinto the groundimmediatelyunderthe •ouree,and are the first
S77
J. Acoust. Soc. Am. Suppl. 1, Vol. 82, Fall 1987
11:35
JJg. Bcam-to-modeconversionof a high-frequencyGaussianP-wave
inputin anelasticplateembedded
in vacuum.I.T. Lu, L.B. Felsen,and
J.M. Klosner(Polytechnic
University,Farmingdale,
NY 11735)
Gaussianbeams,either individuallyor as synthesizing
basisfields,
provide
useful
models
fortheresponse
duetoGaussian
ormoregeneraliy
shapedhigh-frequency
sourceinputs,respectively.
Whenpropagating
intoa layeredenvironment,
an initiallyweli-collimated
beamundergoes
diffusionafter successive
reflections,and is convertedessentiallyinto the
oscillatory
patternofoneor moreguidedmodes.
Thediffusion
process
is
accelerated
in thepresence
of multiwave
coupling
at interfaces,
forexample,theP-SVcoupling
atthefreeboundary
ofanelastic
solid.Thisphenomenology
isexamined
hereforatwo-dimensional
P-wave
beaminputinto
an elasticplateembedded
in vacuum.Thebeamismodeled
viathecomplexsource
pointmethodwhereby
a Gaussian-waisted
inputisgenerated
froma lineforcingfunctionby assigning
complexvaluesto the source
coordinates.
This schemeavoidstheneedfor plane-wave
spectraldecem-
position
andsynthesis,
buttheanalyticcontinuation
to complex
source
coordinates
of variouslinc forceGreen'sfunctionrepresentations
in a
layeredmediumrequiresprecautions,
whichare discussed.
Numerical
calculations
of P andSg'potentials,
stresses
andmotions,performed
by
beamtrackingandmodesummation
at successive
crosssections,
reveal
the beam-to-mode
transitionprocess,
and suggest
that a hybridbeammodealgorithmprovides
the mostdirectandcogentphysicalexplanation. [Work supportedby AFOSR andONR. ]
114th Meeting: AcousticalSociety of America
877
nearthestagnation
pointofa bluffbodywill beexamined.
The stabilityof
11:50
J J9. Acoustic wave interactions at a mean-flow st•guation point.
CharlesThompsonand Martin Manley (Departmentof Electrical
Engineering,
Universityof Lowell,OneUniversityAvenue,Lowell,MA
01854)
suchflowswill be investigated.It will be shownthat streamwisevorticity
generated
by the Stokeslayercanenhancethe receptivityof the meanflowboundarylayerto free-stream
disturbances.
The downstreamevolution of the vortical motion of the fluid will also be modeled and the results
will be presented.[Work supportedby AnalogDevicesProfessorship.]
The interaction between acoustic disturbances and the mean-flow
THURSDAY
MORNING,
19 NOVEMBER
1987
TUTTLE
SOUTH ROOM, 9:00 TO 11:35 A.M.
SessionKK. PhysicalAcousticsVI: GeneralTopicsin PhysicalAcoustics
Michael E. Haran, Chairman
IBM FederalSystems
Division,Manassas,Virginia22110
Chairman's lntroductionB9:00
ContributedPapers
9:05
KKI. Meusurementof the universalgasconstantR usinga spherical
acousticresonator.M. R. Moldover, J.P. M. Trusler, T. J. Edwards,
J. B. Mehl, and R. S. Davis (ThermophysicsDivision, Center for
ChemicalEngineering,
NationalBureauof Standards,
Gaithersburg,
MD
2O899)
A spherical
acoustic
resonator
hasbeenusedto redetermine
theuniversalgasconstantR with an uncertainty
of 1.8 ppm (standarddeviation).To accomplish
this,threesubtasks
werecompleted.
( 1) Thevolumeofa spherical
shellwasdetermined
byweighing
themercuryrequired
to exactlyfill it at thetemperature
of thetriplepointof water,273.16K.
(2) With theresonator
filledwithcommercially
suppliedargon,theresonancefrequencies
of the radialmodesweremeasured
asa functionof
pressure.
Usingourtheoretical
modelforthecavity,thefrequency
measurementswere combined with the mean resonatorradius determined in
subtask
( 1) toobtainthespeedofsoundin commercially
supplied
argon.
(3) Finally,thespeedof soundin thecommerically
supplied
argonwas
compared
to thespeed
of soundin a "standard"
sample
whosechemical
andisotopic
composition
wasaccurately
established.
discovered.
Previously,
solidscouldbeclassified
ascrystalline,
withperiodiclatticespacing,
orasglassy,
withrandomsitespacing.
Thenewquasicrystalstructures
appearto havelong-range
order,showing
sharppeaks
in theFouriertransformspaceasin a periodicsystem,but theyalsohave
properties
thatareimpossible
foranyperiodic
structure,
suchasfivefold
rotationalsymmetry.
For periodicsystems,
Bloch'stheoremmaybeused
to understand
physical
properties
suchaswavetransmission,
andit isof
currentinteresttolearnif anysuchsymmetrytheorems
applytoquasiperiodicsystems.
Rigorous
theorems
forone-dimensional
quasiperiodic
patternsbasedon a Fibonacci
sequence
suggest
thatsucha patternmaybe
usefulin control of vibration transmissionin rib-stiffenedplates.How-
ever,in twoandhigherdimensions,
littleisknownabouttheconsequences
of quasiperiodic
structure.
Recently,acoustic
measurements
havebeen
madeona two-dimensional
quasiperiodic
systemandthefrequency
spectrum,densityof states,andeigenmode
patterns,showing
somefeatures
uniqueto thequasiperiodic
pattern,havebeendetermined.
[Worksupported,in part,by NSF DMR 8701682andthe Officeof Naval Research.]
9:50
KK4. Interaction of a soundbeamwith a two-fluidinterface.Jacqueline
9:20
KK2. Effects of carbon dioxide and humidity on some acoustic and
thermodynamicpropertiesof air. George S. K. Wong (Division of
Physics,National ResearchCouncilof Canada,Ottawa, Ontario K1A
0R6, Canada)
The theoreticaldata on the combinedeffectsof humidity and carbon
dioxidecontentonsomephysicalproperties
of air, suchasthecharacteris-
ticimpedance
pcandthesound
speed
c,thespecific
heatsCpandC,, and
their ratio y, and the densityp, havebeenstudied.In general,overthe
temperature
range0•-30øC,thenormalized
values
C•,/(C•,
and C/Co,becomelargerwith the inclusionof humidityand risingtemperature;and they are alsoinverselyproportionalto the CO2 content.
Similarly,P/Po andpc/( pC)oare proportionalto the CO2 content,but
they are inverselyproportionalto humidity and temperature.However,
thenormalizedvaloe7//7/obecomes
smallerwith theincrease
of humidity,
temperature,and CO2 content.The abovereferencevalues,whichare
indicated
witha zerosuffix,
suchas(Cr) oandpo,
refertodrystandard
air
Naze Tj•tta (Departmentof Mathematics,
The Universityof Bergen,
5007 Bergen,Norway, and Applied ResearchLaboratories,The
Universityof Texasat Austin,Austin,TX 78713-8029),Hanne Sagen
(Departmentof Mathematics,
The Universityof Bergen,5007Bergen,
Norway), and SigveTj•tta (Department of Mathematics,The
Universityof Bergen,5007 Bergen,Norway, and Applied Research
Laboratories,The Universityof Texas at Austin, Austin, TX 787138029 )
The reflection and transmission of a real sound beam at the interface
betweentwo homogeneous
and dissipative
fluid layersare considered.
Numericalresultsare obtainedby usinga fastFouriertransformalgorithm.For thetransmitted
field,theyshowthat,at a givenincidentangle,
the directionanddisplacement
of thebeamdependcriticallyon the absorptioncoefficient,
andonthedistance
betweenthesourceandtheinterface.Variousasymptotic
formulasarealsopresented,
whichallowfor a
physicalinterpretation
of thenumericalresults.
10:05
(314 ppmCO2content)at 0 øCandat a pressure
of 101.325kPa.
KKS. The role of cutoff modes in waveguides with boundary
9:35
KK3. Eigenmodesof quasicrystals.J. D. Maynard and Shanjin He
(Departmentof Physics,
The Pennsylvania
StateUniversity,University
Park, PA 16802)
Recently,a newstateof matter,referredto as quasicrystalline,
was
S70
J.Acoust.
Soc.Am.Suppl.
1,Vol.82,Fall1987
discontinuities.R. Sen (Department of Engineering Science and
Mechanics,Virginia PolytechnicInstitute and State University,
Blacksburg,VA 24060) and CharlesThompson(Departmentof
ElectricalEngineering,
TheUniversityof Lowell,Lowell,MA 01854)
Whena waveguide
witha boundary
discontinuity
isexcitedby a lowfrequency
planewave,cutoffcrossmodesareinduced
by thediscontin-
114thMeeting:
Acoustical
Society
ofAmerica
$78
uity. Althoughthesemodesare discernible
only in the vicinityof the
discontinuity,
theyact as sourcesin the incompressible
localflow,and
therebyaffectthemeanacoustic
pressure.
Thishasa profoundeffecton
the farfieldreflectionand transmission
coefficients
R and T, and, conse-
quently,
onthejunctionimpedance
Z. Themethod
of matched
asymptoticexpansions
shallbeusedandit will beshownthat,byproperlyaccounting for the crossmodes,the frequency
rangeof validityof asymptotic
estimates
of R, T, andZ canbe greatlyextended.The possibility
of improvingtheseestimates
bytheuseofPad6fractionswill alsobediscussed.
Finally, the formal difficultiesof incorporatingcutoff modesinto the
acousticfielddescription
arediscussed,
andan extension
of themethodof
matchedasymptoticexpansions
to circumventthem is presented.
10:20
KK6. Hot-film anemometerresponseto hydroacousticparticle motion
under imposedbias flow. Pieter S. Dubbelday (Underwater Sound
ReferenceDetachment,Naval ResearchLaboratory,P.O. Box 568337,
Engineering
and Ferroelectrics
Laboratory,INSA, 69621Villeurbanne
Cddex,France)
Standardson piezoelectricity[IEEE Trans.SortiesUltrason.SU-31
(March 1984) ] describe
theanalysis
of vibrations
on piezoelectric
materials havingsimplegeometricalshapes.The resultsare basedon linear
piezoelectricity,
and resonance
modesare treatedas noncoupled
vibrationalmodes.However,in general,realmaterialsinvolvecoupledmodes.
In addition,they may haveonedimensionthat is not greaterthan the
others.Therefore,it is not possibleto stateconciselya specificset of
conditionsunder which the definitionsand equationscontainedin the
standards
apply.However,for pure-mode
directionpropagation,
themechanicaldisplacements
are only relatedto a singlecoordinate,and the
electricalimpedance
andgeneralelectromechanical
couplingfactorequationscan be determined.With the sameassumptions
as in the thickness
excitationof plates[ M. Brissaud,J. Acoust.SOc.Am. SuppLI 79, S46
(1986) ], that is, completelystress-free
bounda• conditionsandlossless
piezoelectricmateddais,
the impedanceequationof thediskcanbegiven.It
shouldbenotedthat,whenthepiezoelectric
coefficients
c• andh3•vanish,the impedancereducesto an equationthat issimilarto that givenby
Mason'sone-dimensional
model [Phys. Acoust.I ( 1964}].
Orlando, FL 32856-8337}
The response
of a hot-filmanemometer
to verticalhydroacoustic
particlemotionisinfluencedby freeconvection,whichactsasa biasflow.The
outputwasshownto be proportionalto particledisplacement
for a wide
rangeofparameters
[ P.S. Dubbelday,
J.Acoust.Soc.Am. 79, 2060-2066
(1986)]. It wasexpectedthat an imposedbiasflowwouldincreasethe
outputandremovethedependence
onthedirectionofgravity.Therefore,
a hot-filmsensor(diameterd) wassubjected
to an underwaterjet from a
nozzle.The ratio of the voltageoutputs,due to a hydrostaticfield,with
and without this dc flow, wasmeasuredas a functionof frequencyfor
variousflowspeeds.
The outputshoweda transitionfrom beingproportional to particlespeed,to beingproportionalto particledisplacement,
dependingon the angularfrequencycoand imposedflow speedv. The
transitiontakes place when a dimensionless
number f•, definedas
1• = r•l/v, isoforder1.Thisphenomenon
hasconsequences
for theinterpretationof the measurement
of turbulence,whereit iscustomaryto use
the dc velocitycalibrationwithout referenceto frequencydependence.
[Work supported
by theONR. ]
11.•5
KK9. Photoacousticeffectfrom fine particles:Grain size and frequency
dependence
of the acousticyield. J. Pelzl,U. Netzelmann(Insfitut fdr
Experimentalphysik,
Ruhr Universit•it,D-4630 Bochum 1, Federal
Republic of Germany), and D. Schmalbein(Bruker Analyfische
Messtechnik GmbH, D-7512 Rheinstctten, Federal Republic of
Germany )
The audioacoustic
responseof air in contactwith finecopper-sulfate
particlesIhat are heatedperiodicallyby •sonant microwaveabsorption
hasbeeninvestigated
asa functionof the modulationfrequency( 10Hz to
5 kHz) of themicrowavepowerfor differentparticlesizes( 10p to I mm ).
Absolutevaluesofthephotoacoustic
(PA) yieldarcobtainedbynormalizationwith the simultaneously
detectedconventionalEPR signal.The
PA-signalgeneration
efficiency
hasbeenfoundto increase
stronglywith
decreasing
particlesizewith the maximumvalueoccurringat a distinct
size-dependent
frequency.
Thesizeandfrequency
behaviors
of theamplitudeand phaseshiftof the PA-signalare analyzedtheoretically
on the
basisof a modelthat considersa singleisolatedparticle.
10.'35
KK?. On the extensionof the acousticv•riationalprinciple,from media
at restto potentialmeanflows.L. M. B.C. Campos(InstitutoSuperior
T•cnico,1096LisbonCodex,Portugal)
The well-knownacousticvaddationa]
pddnciplc
for soundin a medium
at rest [e.g.,Morseand Ingard,Theoretical
,4coustics
(McGraw-Hill,
NewYork, 1968},p. 248],is generalized
to theacoustics
of a potential
meanflow,andisusedto derive:(i} theenergyequationfor soundin f•c
and ductedflows;(ii) the waveequationin an inhomogeneous
fluid at
rest,in low Mach numberandin high-speed
convection.
{iii) the Web-
11:20
KKI0. Extrapolation of acousticfields by meansof source function
estimation. G. Elias and F. Payen (Department of Physics,Office
National d'Etudes et de RecherchesA6rospatiales,BP 72, 92322
sters'hornwaveequations
andwaveequations
for low Maeh numberand
Chatilion Cedex, France)
high-speed
nozzles.Case Off) aboveappliesto quasi-one-dimensional
soundpropagationin nonuniformducts,and generalizes
the variational
Extrapolationof acousticpressures
is neededwhen farfieldmeasureprincipleofWeibel [J. Acoust.SOc.Am. 75, 105-106( 1955}] to include
- mentsare not possible.Most of the methodsusuallyusedare basedon a
the effectsof potentialmeanflow. The linearacousticwaveequations
direct applicationof Kirehhoff'sintegralor on spectraldecomposition,
derivedfromthevariafional
principlearechecked
by comparison
with
whichleadsto a finesamplingof a closedsurface.The presentmethod
exactnonlinearequationsobtainedby a distinctmethod.
requiresonlya limitednumberof microphones
andconsists
of a source
functionestimation.In the firststep,the microphonearray is usedas a
focusedantennafor measuringthe overallextentof the sourceregion.In
thesecondstep,a biorthogonal
basisiscomputedfor theexpansion
of any
sourcefunctionlimited to the previousspatialextent and the pressure
radiatedon the array. Then, by projectingthe measuredpressureon this
10:50
KKS. Three-dimensiooal analysis for radial and thickness mode
excitation of piezoceramic disk. Michel Bddssaud (Electrical
S79
d. Acoust. Soc. Am. Suppl. 1, Vol. 82, Fall 1987
basis,
anestimate
ofthesource
function
canbeobtained
toextrapolate
the
acousticpressurein the farfield. Simulationsshow a good agreement
betweenreal and estimateddirectivitydiagramsand the preciselimitationsof this method. [ Work supportedby DCN. ]
114th Meeting: Acoustical Society of America
S79
THURSDAY
MORNING, 19 NOVEMBER 1987
UM AUDITORIUM LOBBY AND PREFUNCTION AREA, 9:00 A.M. TO 12:00NOON
Session
LL. Speech
Communication
V: Perception
(PosterSession)
Linda Polka, Chairman
Department
of Communicology,
CB•4229, University
of SouthFlorida,Tampa,Florida33612
ContributedPapers
All posters
willbedisplayed
from9:00a.m.to 12.00noon.Toallowcontributors
theopportunity
toseeother
posters,
contributors
ofodd-numbered
papers
will beat theirposters
from9:00to 10:30a.m.,andcontributors
of even-numbered
paperswill beat theirposters
from 10:30a.m.to 12:00noon.
LLI. Individualdifferences
in theperception
of cuesfor initialstopplace
and voicingcontrasts.Valerie Hazan (Departmentof Phoneticsand
Linguistics,
UniversityCollegeLondon,4, Stephenson
Way, London
NW1 9DY, United Kingdom)
Fifteennormal-hearing
adultsweretestedon theirabilityto identify
synthesized
stimulifromthreeinitialstopcontrasts.
Twoplacecontrasts,
BAIT-DATE andDATE--GATE, werepresented
in threeconditions.In
the "full-cue"condition,the placecontrastwassignaled
by changes
in
burstfrequencyand F2/F3 transition.In the two "reduced-cue"condi-
ticms,
thecontrasts
weresignaled
byonlyoneof thesetwocues.A voicing
contrast,GATE-KATE, waspresented
in two conditions:
a 'Tull-coe"
condition,in whichthe contrastwasmarkedby changesin VOT andFI
onset;anda "VOT cue"condition
in whichtheFI onsetwasfiat.Group
resultsshowsignificantvarianceacrossconditions,both in termsof the
phonemeboundaries
and identification
functiongradientsobtained.In
addition,individualdifferences
werefoundin thelabelingof reduced-cue
conditions.
Somesubjects
showed
littledifference
between
thelabelingof
the full-cue and the reduced-cue conditions of the BAIT-DATE
and
CATE-KATE contrasts,
whileothersweretotallyunableto establish
a
contrast for some conditions.
syllablesare usedasstimulusmaterials.Nonsenseconsonantclusterscon-
stitutea classof sounds
that arelargelydevoidof semantic
context,yet
theyrepresent
a higherlevelofphonological
organization.
Consequently,
therecognition
of thesesoundsmayreflectprocessing
levelsthatarenot
involvedin theperception
of simplerstimuli.In thepresentstudy,consonant clusters(CCV or CCCV in/a/vowel
context), as well as their
singletone
members,
werepresented
to listenersagainsta background
noiseat 10, 5, and 0 dB S/N'. The resultsshowsystematictrendsin terms
of the frequencyand the patternsof recognition
errors.In general,the
proportion
ofsubstitufions,
additions,
anddeletions
resemble
thepattern
of errorsobservedin productionerrorsof consonant
clusters.Theseand
furtherresultswill bepresented
anddiscussed
at themeeting.
LIA. Auditoryfactorsin theperception
of stopsandglides.Margaret
A. WalshandRandyL. Diehi (Department
of Psychology,
University
of Texas, Austin, TX 78712)
Thereissomedisagreement
in theliteratureaboutthe relativecontri-
butionofformanttransition
durationandamplitude
risetimeincuingthe
stop--glide
distinction
(e.g.,[hi vs [w] ). Lackof resolution
on thispoint
ispartly dueto the confoundingofthesetwo variablesin moststudies.For
a seriesof identification
experiments,
setsof synthetic[ba] and [wa]
LL2. Perception of S-to-unvoieed-stop
transitions in natural and
synthetic
speech.
JanP.H. vanSantenandBeverlyM. Glasgow(AT&T
Bell Laboratories,
Murray Hill, NS 07974)
The perceptualroleof the preclosure
portionof S-K, S-T, andS-K
.transitionswas investigated.Mahalanobisdistancesbetweenreflection
coefficientvectors(derived from linear predictivecodinganalysis)
showedthatdifferences
between
thestopsarcaslargebeforetheclosureas
during the release.In a paired-comparison
experimentusingnatural
speech,listenerspreferredconsistent
words (e.g., S-T followedby
TOUT) overinconsistent
words(e.g.,S-K followedby TOUT). However,perceptual
differences
weresubtle,andthestopidentitywasneverin
question.In a subjective
qualityratingexperimentusingsyntheticspeech,
there were no differences
betweenconsistentwordsand stop-neutral
words(S-silencefollowedby, e.g.,TOUT), but inconsistent
wordswere
givenlowerratings.It isconcluded
thattheperceptual
roleof thepreclosureportionofS-to-anvoiced
stoptransitions
issmall,andcanbeignored
in currentspeech
synthesizers.
Thisapparent
conflictbetween
theexperimentalresultsand the Mahalanobisdistanceanalysismay involvethe
perceptualsalleheyof the dimensions
alongwhichvectorsdifferand the
effectsof amplitude.Finally, the resultsdemonstratethe sensitivityof
subjective
qualityratings.
LL•. Ree•nition of consouantclusters.Moshe Yuchtman (Project
Phoenixof Madison,Inc., 2001S.StoughtonRoad,Madison,W153716),
]oseph Stemberger (Department of Linguistics, University of
Minnesota,
Minneapolis,
MN 55455),andChristopherMartin (Speech
ResearchLaboratory,Departmentof Psychology,
IndianaUniversity,
Bloomington,IN 47405)
Perceptualprocessing
of speechhasbeenfrequentlystudiedusing
analyses
of consonant
recognition
errors.Typically,nonsense
CV or VC
S80
J.Acoust.
Soc.Am.Suppl.
1,Vol.82,Fall1987
stimuli were created in which transition duration and rise time varied
orthogcmally.
Bothvariables
affected
labelingperformance
in theexpecteddirection,
buttransition
durationwasbyfarthemoreimportantfactor.
A similarpatternof resultswasobtainedfor singlesine-wave
stimulithat
modeledthe risetimes,frequencytrajectories,and durationsof the first
formantin the [ba] and [wa] stimuli.A likelyauditorybasisfor boththe
speech
andnonspeech
effectsisthatrapidfrequency
transitions
andshort
risetimesbothcontributeto a higherdegreeof spectralsplatter(i.e.,
dispersion
of energyacross
a widefrequency
band),whichmaybea principalcuefor abruptonsets
in general.[Work supported
by NICHD.]
LLS. Identificationof stopconsonants
from continuousspeechin limited
context. Lori P. Lamel (Room 36-545, Department of Electrical
Engineeringand Computer Science,and ResearchLaboratory of
Electronics,Massachusetts
Institute of Technology,Cambridge,MA
02139)
Thispaperdescribes
a series
ofperceptual
experiments
aimedat evaluatinglisteners'abilityto identifysingletonstopconsonants.
The stimuli
consistedof portionsof speechextractedfrom a corpusof about 3600
sentencesspokenby over 4.50talkers.A variety of factors,suchas the
stresspattern,syllableposition,andphonemicenvironment,weresystematically varied to determinethe extentto which thesefactorsinfluencethe
listeners'decision.At least20 listenersheardsyllable-initialstopsin one
taskandnonsyllable-initial
stopsin another.In eachtask,onlythe immediatesurroundingcontextwasavailable.Overall identificationrateswere
betterthan97% forsyllable-initial
stopsand85% forthenoninitialstops.
In thesyllable-initial
case,75% of theerrorswerein voicing,predominantlyvoicedstopsbeingheardas their voiceless
counterparts.
For the
noninitialstops,88% of theerrorswerealsoin voicing.However,in this
task,mostof theerrorswerevoiceless
stopsheardasvoiced.Almost70%
oftheerrorsforthenoninitialstopsinvolved
alveolars,
whereas
nopartic-
114thMeeting:
Acoustical
Society
ofAmerica
S80
ular placeof articulationaccountedfor mostof the errorsfor the initial
stops.Factorsotherthansyllablepositionwill alsobediscussed,
andcomparisons
will bemadetootherstopidentification
studies.[ Worksupported by DARPA undercontractN00014-82-K-0727,monitoredthrough
the Officeof Naval Research.]
LL6. The roleof rateof transitionin placeperception.
ReneeA. E. Zakia
and John Kingston(DMLL, Morrill Hall, CornellUniversity,Ithaca,
NY 148534701 )
Kewley-Port,Pisoni,and Studdert-Kennedy["Perceptionof static
anddynamicacousticcuesto placeof articulationin initialstopconsonants," J. Acoast. Soc. Am. 73, 1779-1793 (1983)] showedthat initial
bilabialand alveolarstopscanbe reliablyidentifiedfrom informationin
the first20 msof the syllable,includingthe burstand the beginningof the
transition.Identificationof stopsas velarsrequireda longerstimulus,
indicatingthat a slowchangein formantfrequenciesis characteristicof
this placeof articulation.If rate of changeof formantfrequencies
is a
positivecueto theidentification
of velarstops,it wouldbepredictedthat
varyingrate of changewouldaffecttheir identification.To testthis prediction,syntheticstop-vowel
stimuli,derivedfrom naturaltokens,consistingof all combinations
of [b,d,g] andthe vowels[i,a], wereeditedto
producestimuliwithfourratesof formanttransition:100,75, 50,and25
ms.Listenersin thisexperimentidentifiedplaceofarticolationconsistently regardless
of rate of transition;specifically,there wasno significant
interactionbetweenplaceandrateof transition.This wouldindicatethat
a slowformanttransitionis not necessary
ira stopis to be identifiedasa
velar.There was,however,a significantinteractionbetweenvoweland
placeof articulation,whichimpliesthat themagnitude,if notthe rate,of
the transilionis a significantcueto place.
LL7. Rate versus duration of formant transition as a discriminative cue.
Robert $. Porter, Jr.
(Kresge Hearing Research Laboratory,
Department
ofOtorhinolaryngology,
LSUMedicalCenter,NewOrleans,
LA 70112and Departmentof Psychology,Universityof New Orleans,
New Orleans, LA 70122), Jane Collins, John K. Cullen, Jr. (Kresge
Hearing ResearchLaboratory,Departmentof Ortorhinolaryngology,
LSU Medical Center, New Orleans, LA 70112 and Department of
Communication
Disorders,Collegeof Arts andSciences,
LouisianaState
Universitj', Baton Rouge, LA 70804), and Dena F. Jackson(Kresge
Hearing ResearchLaboratory, Department of Otorhinolaryngology,
LSU Medical Center, New Orleans, LA 70112)
The linguisticmessages
of speech
cannotbeclearlyreadin itstime-by-
frequency-by-amplitude
signature
norisit manifest
in thecorresponding
psychoacoustic
domain.It issuspected
that importantaspects
of speech
messages
may, instead,be revealedin higher-order,rate-of-change
attributesofspeech
signals
andtheircorresponding
perceptual
representation.
In a recentexplorationof rate-of-change-of-spectrum
[Besinget al., J.
Acoust.Soc.Am. Suppl. 1 gl, S54 (1987) ], 300-ms,second-formant-like
signalswete used,whichwerevariedin onsetfrequencyto producevaria-
tionsin therateof a 30-ms,initialtransition.Resultssuggested
listeners
may userate-of-frequency-change
to discriminateamongthesesignals.
The presentstudyexaminedthresholdsfor rate changesproducedby
transitiondurationvariationinsteadof onsetfrequency.
Transitionsbeganat either 1500or 2100 Hz and roseor fell to a steadystateof 1800Hz.
Standard transition durations of 60 and 124 ms were used. Discrimination
wascomparedfor risingandfallingtransitions
presented
eitheralone,or
presented
togetherwith first-formantlike
resonances.
Resultsfor tensubjectssuggest,
asin theprevious
study,thatlisteners
mayuseperceived
rate
changerather than perceiveddurationto discriminatethesespeechlike
signals.[Work supportedby NIH-NINCDS and LouisianaLionsFoun-
resultshavenot beenobtainedwhen natural adaptorswere employed
[Summerfieldet al., J. Phonet. 8, 491-499 (1980); Shuster and Fox,
ASHA 28, 72 (1986) ]. In the presentstudy,subjectsproducedexamples
ofthetoken[rat"i] priortoadaptation
andthenafterperceptual
adaptationwitha naturallyproduced
[raphi].Voiceonsettimewasthenmeasuredforeachspoken
utterance.
!t wasfoundthatVOTsweresignificantly shorterafter adaptationto the bisyllablethan they were prior to
adaptation.Theseresultsare similarto thoseobtainedwith synthetic
adaptorsandsupportthenotionthatperceptuomotor
adaptationreflects
a perception-production
link.
LL9. Central and peripheral representationof whisperedand voiced
speech.Arthur G. Samuel(Departmentof Psychology,
Box 11A Yale
Station, New Haven, CT 06520)
Whisperedspeechis verydifferentacoustically
fromnormallyvoiced
speechyet listenershavelittle troubleperceivingwhisperedspeech.Two
selective
adaptationexperiments
exploredthebasisfor thecommonperceptionof whisperedand voicedspeech,usingtwo/ba/-/wa/continua
(onevoiced,onewhispered).The firstexperiment
usedtheendpoints
of
eachseriesas adaptors,and severalnonspeech
adaptorsas well. Speech
adaptorsproduced
reliablelabelingshiftsof syllables
matchingin periodicity (i.e.,whispered-whispered
or voiced-voiced);
somewhat
smallerelfeetswerefoundwithmismatched
periodicity.
A periodicnonspeech
tone
withshortrisetimeproduced
adaptation
effects
likethosefor/ha/. These
shiftsoccurredfor whisperedtestsyllablesas well asvoiced,indicatinga
commonabstractlevelof representation
for voicedandwhisperedstimuli.
Experiment2 replicatedandextendedexperimentI, usingsame-ear
and
cross-earadaptationconditions.There wasperfectcross-eartransferof
the nonspeech
adaptation
effect,againimplicatingan abstractlevelof
representation.
Theresults
supporttheexistence
of twolevelsof processing for complexacousticsignals.The cornmortality
of whispered
and
voicedspeech
arisesat thesecond,
abstract
level.Boththislevel,andthe
earlier,moredirectlyacoustic
level,aresusceptible
to adaptationeffects.
[Work supported
by AFOSR.]
LLI0. Modeling the perception of vowel-like formant peaks.
Hector Jaykin, Brian Hanson, Paul Neyrinck, and HisashiWakita
(SpeechTechnologyLaboratory,3888StateStreet,SantaBarbara,CA
93105)
An improvedmodeloftherelationship
ofharmonicstructure
to vowel
perception
is proposed
andevaluated.
Jaykin,Hermansky,
andWakita
Illth InternationalCongress
of PhoneticSciences,
Tallinn, Estonia,
USSR(1987)] compared
listeners'
responses
toone-formant
stimuliwith
the computedweightedaverageof the two mostprominentharmonics
[ themostimportantfrequency,
or MIF of Carlson,Font,andGanstrom,
•4uditory,4nalysis
and Perception
ofSpeech(Academic,London,1975)]
appliedwithdifferentscaling
factors.With thismeasure,
a relativelyexpandedscalesuchasmagnitudecomesclosest
to perceptual
testresults.
To improveon the characteristics
of MIF, a criticalbandanalysiswas
adoptedand Chistovichand Chernova [SpeechCommon. 5, 3-16
(1986)] werefollowedin applyinga centerofgravityformantestimation
(CO). Because
CG is highlydependent
on the integration
interval,an
iterativeprocesswasused,with eachiterationchoosingthe frequency
limitsfor the nextanalysisuntil convergence.
Initial resultssuggest
that,
whileCO is lessaffectedby amplitudeexpansions
thanM1F, themagni-
tudespacemostcloselyapproximates
listeners'responses
for the oneformant stimuli. Evaluations of the method with multiformant stimuli are
alsopresented.
dation. ]
LLII. Acousticversusphonologiealcontexteffectsin the perceptionof
formant transition continua. Terrarice M. Nearey and Sherrie
LLS. Perceptuomotor adaptation to natural speech adaptors. Linda
1. Shuster (Department of Speech Pathology and Audiology, West
Virginia University,Morgantown,WV 26506-6122)
E. Shammass(Departmentof Linguistics,Universityof Alberta,
Perceptuomotoradaptationhas beendemonstratedusingsynthetic
adaptors[Cooperand Nager, J. Acoust.Soc.Am. 58, 256-265 ( 1975);
JamiesonandCheesman,J. Phonet.15, 15-27 (1987) ]. However,similar
articulationin formant transitioncontinuais perhapsthe archetypalex-
S81
J. Acoust.Soc.Am. Suppl.1, VoL82, Fall 1987
Edmonton T6G IE7, Canada)
The effectof the followingvowelon listener's
judgmentsof placeof
ampleof contextsensitivity
in speech
perception.
Is thissensitivity
explicablein termsof acousticcontextaloneor mustthejudgedphonological
114thMeeting:AcousticalSocietyof America
S81
identityof thefollowingvowelalsobeconsidered?
Shammass
[unpub-
ated.Next, a sensory-perceptual
transformation
is appliedto generate
a
lisheddissertation,Universityof Alberta (1985) ] designedtransition-
unitaryperceptual
path.Sincethesensory-perceptual
transformation
is
reactive,
theperceptual
pathovershoots
theburst-friction
onsetof the
tokenandentersa physically
unrealizable
octantof APS,whereinthe
perceptual
targetzones
forthestopsarelocated.
Distincttargetzones
are
continuaexperiments
involvingambiguous
and nonambiguous
vowel
stimulito examine
thisquestion
in detail.Linearlogisticanalysis
of these
dataconfirms
thesystematic
roleofacoustic
contexteffects,
butindicates
thatthephonological
contexteffects
areofa highlyrestricted
natureand,
furthermore,are both task and listenerdependent.A summaryof this
analysis
is presented
andtheresultsarediscussed
in thecontextof other
resultsfrom the literat.
ure (includingthoseof Mermelstein,Massaro,
Ohala,andRepp). The evidence
is consistent
with the hypothesis
that
phoneme-sized
units(ratherthandiphones
or largerunits)serveasthe
primaryinterface
between
acoustic
cuesandphonological
units.
estimated
for thestops[p,t,k,d,b,g],for h-likeaspiration,
andfor voice
bars.[Supported
by AFOSR andNINCDS.]
LLI$. Locationsof the burst onsetsof stopsin the auditory-perceptual
space.
Allard Jongman
(CentralInstitutefortheDeaf,SaintLouis,MO
63110)
LLI2. Identification of "hybrid" vowels in sentencecontext. James
J. Jenkins and Winifred Strange (Department of Psychology,
Universityof SouthFlorida,Tampa,FL 33620)
It hasbeendemonstrated
that listenerscanidentifytheintendedvowel
in a CVC syllableevenwhenthe vowelnucleushasbeenattenuatedto
silence,leavingonlyongiides
andoffglides(silentcentersyllables).VerbruggeandRakerd [ Lang.Speech29, 39-57 (1986)] constructed
"hybrid" silentcentersyllablesby crosssplicingongiidesand offglidesof
citation-formCVC syllablesspokenby a maleanda femaletalkersuch
thatformanttrajectories
werediscontinuous.
Identification
oftheintendedvowelin hybridsyllables
wasnolessaccuratethanvowelidentification
ofthesingle-talker
silentcentersyllables.
Thepresentstudyreplicates
this
researchwith syllablesspokenin a carrier sentence,"I say the word
/dVd/some more," usingten American-English
vowels.Hybrid silent
centersyllables
werepreparedby crossing
thestimulussentences
sothat
PreliminaryLPC analyses
of thevoiceless
stopconsonants
[ p,t,k] in
thecontextof thevowels[i,•,t,a,u,u] producedin realCVC wordsby one
maleandonefemalespeakersuggest
a methodfor locatingformantsin
burst-friction
spectra.Specifically,
a 24-msHammingwindowwascenteredover the onsetof the burst.First, the spectralpeakwith maximum
amplitude
below6 kHz waslocated.Then,movingfromleftto right,the
centerfrequencies
of the firsttwo peakswithin10 dB of the maximum
werepickedastheburst-friction
components
BF2andBF3.Furthermore,
in thosecaseswhereBF2 hadbeenpickedandBF3 wasseparated
from
BF2by 2500Hz or more,thefrequency
valuefor BF2wasalsousedfor
BF3. Theseburst-friction
prominences
werethenconverted
intocoordinates of the auditory-perceptual
space:x=Iog(BF3/BF2) and
z = 1og(BF2/SR),whereSR is the sensoryreference.
This methodof
analysis
enabledusto distinguish
thestops,in termsof placeof articulation,with goodaccuracy.[Work supported
by AFOSR.]
the sentence started with one talker and switched to the other after the
silentportionof the testsyllable.Silentcenterstimuliwerepreparedfor
eachtalkerseparately
ascontrols.Vowelidentification
wasasaccuratein
thehybridconditionasin thecontrolconditions
suggesting
that dynamic
syllablestructureprovidestalker-independent
informationaboutthearticulatory/acoustic
event.[Researchsupportedby NINCDS.]
LLI3. Classification
of vowelproductions
by meansof perceptualtarget
zones:
A response
toLaderoger
andStuddert-Kennedy.
James
D. Miller
(Central Institutefor the Deaf, SaintLouis,MO 63110)
In discussion
ofmypaper[Miller,J. Acoust.Soc.Am. Suppl.81,S16
(1987)] at the 113thMeeting,Dr. Ladefoged
andDr. Studdert-Kennedy
requested
specific
numbers
regarding
percentcorrectclassifications
of
vowelproductions
achievable
throughuseoftheauditory-perceptual
theory andits perceptual
targetzones(PTZs). At the timeof the 113th
Meeting,theestimated
shapes
andlocations
of thePTZswereverypreliminaryandrepresented
onlya second
iteration(I2). Thepercents
correct for the I2 zoneswere moderate (50%-95%). Basedon reconsideration of older data and on numerous new measurementsmade in our
laboratory,
a newsetof PTZsis beingdeveloped
for the vowels.These
represent
thethirditerationor I3 zones.
TheI3 zoneswill bepresented
andpercentages
of correct
classifications
forseveral
datasetswillbereported.Issues
involved
in developing
decisive
testsof theperceptual
targetzones
will bediscussed.
[Supported
byNINeDS andAFOSR.]
LLI6.
Signal detection analyses of speaker identification accuracy.
{3eorgePapeun(Los A!amosNational Laboratory,Los Alamos,NM
87545),Jody Kreiman (PhoneticsLaboratory,UCLA, 405 Hilgard, Los
Angeles,CA 90024), and Anthony Davis (Departmentof Linguistics,
StanfordUniversity,Palo Alto, CA 94305)
The accuracy
of speakeridentification
canbemeasured
undervarious
experimentalparadigmsincluding:(a) multiple-choice,closed-setexperiments,in whichlisteners
chooseonespeakerfromamonga lineupofn
speakers[as in F. Mc{3ehee,"The reliabilityof the identificationof the
human voice," J. Gem Psychol. 17, 249-271 (1937)]; (b) multiplechoice,open-setexperiments,
in whichlistenerschooseonespeakerfrom
amonga lineupof n speakers,but can alsorefuseto chooseany of the
speakers[as in C. P. Thompson,"Voice identification:
Speakeridextiffability and a correctionof the record regardingsex effects,"Human
Learn. 4, 19-27 (1985)]; and (c) independent-judgment,
open-setexperiments,in whichsubjects
are to makeeachchoiceindependently
of
others[asin {3. Papcun,J. Kreiman,andA. Davis,"Memoryfor unfamiliar voicesat delaysof one, two and four weeks,"submittedfor publication]. In this paper,it wasdemonstrated
that signaldetectionanalysis,
with certainextensions,
makesit possible
to compareresultsacrossthese
diverseexperimentalparadigms,andto seethe essentialidentityof apparentlydisparateresults.A computerprogramis providedto treatcase(b).
LL17. Long-term changesin voice characteristics:Implications for
speakeridentity verification(SlV). Timothy C. Feustel and {3eorge
LLI4. Auditory-perceptual
approachto the stop consonants.
James
A. Velius (Bell
D. Miller and Allard Jong•nan(Central Institute for the Deaf, Saint
Morristown,
Louis, MO 63110)
Usingnaturaltokensandthe synthetic
stimuliof Abramsonand
Lisker[ 6th Internat.Congr.Phonet.(1970)], the auditory-perceptual
theoryshallbeapplied
tosyllable-initial
stopconsonants.
Theburst-fric-
Communications Research, 435
South Street,
NJ 07960)
In a typicalspeakeridentityverification(SIV) scenario,
a talkerfirst
assertsan identityclaim via somemeansotherthan speech.A reference
sampleof the claimedindividual'sspeechis thenloadedinto a pattern
marcherandcompared
againsta newsampleof thesamewordor phrase
tioncomponents
of eachtokenareanalyzed
for thelocations
of their
solicitedon-line. Basedon the similarity of the two utterances,and a
second
andthirdsensory
formants,
BF2andBF3.Thesearelocatedin the
predetermined
criterion,a decisionis madeas to the veracityof the
claimedidentity.One difficultproblemfor SIV applications
is that the
spectral
characteristics
ofa speaker's
voicechange
overtimein waysthat
arepoorlyunderstood.
Utterances
werecollectedfromthreespeakers
at
regularintervalsovera periodof 23 weeks,andwereanalyzedfirstwith
respect
to themagnitude
ofspectral
dissimilarity
overvaryingtimeintervals,and, second,with respectto the effectof thesedifferences
on error
auditory-perceptual
space(APS) by theformulas:
x = 1og(BF3/BF2)
andy = 1og(BF2/SR),whereSR is thesensory
reference.
Theglottalsourcecomponents
arethenanalyzed
for theirsensory
formants:
SFI,
SF2,andSF3.Thesearethenlocatedin APSby equations:
x = 1og(SF3/
SF2),z = 1og(SF1/SR),andz = log(SF2/SF1
). In thisway,a sensory
pathcomprised
ofburst-friction
pointsandgiottal-souree
pointsisgener-
$82
J. Acoust.Soc:Am.Suppl.1, Vol.82, Fall1987
114thMeeting:
Acoustical
Societyof America
$82
ratesfor an SIV decisiontask.The data showan increasein meanutter-
antedissimilarity
of about8% overa periodof 2 weeks,
followed
bya
muchmoregradual
increase
over6 months.
Whiletheabsolute
change
in
meandissimilarity
wassmall,it resulted
in a doubling
of theerrorratefor
sharper
temporal
onsets
andoffsets,
andwithanenhanced
dynamic
range
in thefrequency
dimension.
[Work supported
by DARPA underContractN00039-85-C-0254,
monitored
throughNavalElectronics
Systems
Command.]
the SIV decisiontask from about 5% to 10%.
LL18.Auralsignalprocessing
in thecontextof a digitalhearingmodel.
D.M. Chabries,
M. W. Christiansen,
R. W. Christiansen,
R. H. Brey,
R. W. Harris (BrighamYoung University,Provo,UT 84604), and
M. Robinette(Mayo Clinic,Rochester,MN 55905)
A nonlinear
model
ofthehuman
auralsystem
isproposed.
Utilizing
a
homomorphic
transformation,
themodelisimplemented
ina digitalcomputerandaccounts
fortheFletchercriticalbandsin hearing,
thenonlinearrelationship
between
inputsoundintensity
andperceived
loudness
knownasrecruitment,
aswellasthethresholds
ofaudibility
andthemaximumtolerance
threshold.
Thetransformed
or outputsignaldomainis
identified
asa perceptual
space.
It isshownthatthemodelcanbeusedto
reproduce
theFletcherMunsonequalloudness
contours
fornormalhearingpopulations.
Modification
ofeasilymeasured
parameters
results
in the
generation
of equalloudness
contours
for hearingimpairedindividuals.
Througha combination
oftheforwardhomomorphic
transformation
for
normalhearing
totheperceptual
domain
andtheinverse
mapping
utiliz-
ingparameters
ofa hearing
impaired
individual,
it isshown
thathearing
intelligibility
isdramatically
improved.
It ispostulated
thatsignal
processing
performed
in theperceptual
domainwill produce
results
more
pleasing
andintelligible
tothelistener.
Results
ofauditory
testing
utilizingtheproposed
modelforbothnormalandhearing
impaired
populationsarepresented.
Speech
intelligibility
scores
areshown
toincrease
by
morethan40% (i.e.,from40% toover80%) overpreprocessed
scores
underheadphones
forhearing
impaired
subjects
usedin thesetests.
LLI9. A modelforthetransduction
stageofauditoryspeech
processing.
StephanieSeneft(Room 36-549,ResearchLaboratoryof Electronics,
Massachusetts
Instituteof Technology,
Cambridge,
MA 02139)
A newmodelforthetransduction
stage
ofauditory
processing
isproposed.
Themodelisappliedindependently
toeachof40criticalbandfilter
outputs,spanningthe frequencyrangefrom 100-6400Hz. The model
consists
offourcomponents
in cascade:
aninstantaneous
nonlinear
half-
waverectifier,
a short-term
adaptation
component,
a low-pass
filter,and,
finally,a rapidadaptation
component.
Modeloutputswerecompared
LL21, Alternatemeasures
of response
biasin speech
recognition
by older
listeners.Robin T. K. Zcllcr (Speechand Communicative
Disorders,
Adelphi University,Garden City, NY 11530) and LouisJ. Gerstman
(Departmentof Psychology,
City College,CUNY, New York, NY
10031)
Fifty-twolisteners
rangingin agebetween
50and81years,listened
to
two R-SPIN Tests,responding
to eachstimulusverballyandwith a numericalconfidence
rating.Twelveperformance
measures
werecreated:
for HP andLP itemsseparately,
percentcorrect,d' andP(A ), whichboth
measuresensitivity,and B, which measuresresponsebias;for all 100
items,a meanandstandarddeviationof theratings;andfor theerrorson
theLP items,a meanfrequency
of wordusage,
anda ratingofcontextual
feasibility
bya panelof 15judges.Correlations
withagerevealed
noeffects
fortheHP items,butestablished
thatwithadvancing
age,therewaslower
sensitivity
ontheLP itemsasmeasured
byd' andp(A), butnochangein
B. Additionally,the olderlistenersuseda narrowerrangeof the rating
scaleandmademorecontextually
feasible
errors.No agevariationwas
foundforwordfrequency
oferrors,butall theproposed
responses
were
tentimesmoreprobablethanthemisheardLP words.
LL22. Perceptual and acoustic effects of nonlinear signal processing.
Moshe Yuchtman,Rick Jenison,and Robert Lasky (Project Phoenix
of Madison,Inc., 2001S. StoughtonRoad,Madison,WI 53716)
A commonstrategyfor accommodating
reduceddynamicrangein the
hearingimpairedistheuseof amplitudecompression.
In orderto address
the resultingelevationof the noisefloor, an expansionregionmay be
introduced.This study examinesthe perceptualand acousticconsequences
of suchnonlinearsignalprocessing
of CV andVC monosyllables.
Transmittedinformationfor a systemof distinctivefeaturesasa function
of thedegreeof nonlinearity,
S/N ratio,andspeakerwasevaluated
using
theSINFA procedure.
Acousticanalyses
of processed
syllables
werecarried out in an attemptto definearticulationindexmeasuresthat account
for the perceptualdata.
with availableauditorydata in a numberof differentdimensions
as fol-
lows:( I ) onset
response
totonebursts,
(2) forwardmasking
effects,
(3)
steady-state
behaviorfor vowel-like
stimuli,(4) incremental
response
characteristics,
and(5) synchrony
lossat highfrequencies.
Twodistinct
spectral
representations
arecomputed
fromthemodel
outputs:
anamplitudespeclrum
corresponding
t6 mean-rate
response
anda synchrony
spectrum
whichmakesuseoftemporal
information
to enhance
spectral
peaks.
Themodeliscurrently
beingincorporated
intoa speaker-independentcontinuous
speech
recognition
system
underdevelopment.
[Work
supported
by DARPA underContractN00039-85-C-0254,monitored
throughNavalElectronics
Systems
Command.
]
LL20. Pulse synchronous
analysisof speechusing an auditory
representation.
JamesR. Glassand StephanieSeneft(Room 36-585,
Departmentof ElectricalEngineeringand ComputerScience,and
Research Laboratory of Electronics, MassachusettsInstitute of
Technology,Cambridge,MA 02139)
A procedure
hasbeendeveloped
that automatically
extractspulse
excitation
information
fromthespeech
signal.Thistime-domain
algorithmoperates
on thetransduction
stageoutputsof an auditorymodel
developed
bySeneft
[thismeeting].
Specifically,
robust
inflection
points
aredetermined
froma waveform
obtained
bysumming
thechannel
outputs.Thi• pulselike
representation
provides
information
aboutperiodic
andaperiodic
excitation,
andcanbeusedtoextractperiodicities
in voiced
regions.
Thustheinformation
provided
by thissignalcomplements
the
spectral
information
provided
bymean-rate
response
outputs
oftheauditorymodel.Furthermore,
thissignalcanbeusedto samplechanneloutputspulsesynchronously.
This produces
a spectralrepresentation
with
883
J. Acoust.
Soc.Am.$uppl.1, Vol.82, Fall1087
LL23. Longitudinalchangesin syllablediscriminationamongnormaland
handicappedschoolchildren. Lois L. Elliott and Michael A. Hammer
(Audiology and Hearing Impairment, Northwestern University,
Evanston, [L 60201 )
Cross-sectional
age-related
differences
in discrimination
of voiceonset
time (VOT) [L. L. Elliott, J. Acoust.Soc.Am. $0, 1250-1255(1986)]
and the place-of-articulation
(POA) feature [L. L. Elliott et al., J.
Acoust.Soc.Am. 70, 669-677 (1981)] whenjust-noticeable
differences
amongfive-formant
synthesized
CV syllables
are measured
usingadaptive testprocedures
werepreviouslydescribed.
Resultsare reportedhere
for childrentestedlongitudinally
for 3 consecutive
years.Discrimination
of temporalinformation(VOT) showedlargerchangesover time than
discrimination
of frequency-based
information
(POA). Also,largerperformancedifferences
occurredbetweennormallyprogressing
children
andthosewith learningdisabilities
for VOT thanfor POA. Childrenwith
learningdisabilitiesgenerallyexhibitedpoorerauditorydiscrimination
thannormals;however,theydemonstrated
asmuchlongitudinal
change
in performances
asdidthenormallyprogressing
children(i.e.,therewere
no significantinteractions
betweenyearof testandnormalversushandicappedstatus).[Supported,
in part,by NINCDS andNIH.]
LL24. The role of static spectralpropertiesin vowel identification.
James Hillenbrand
and
Brendan
J. McMahon
(RIT
Research
Corporationand RochesterInstitute of Technology,75 Highpower
Road, Rochester, NY 14623)
The classicstudyof Petersonand Barney [J. Acoust.Soc.Am. 24,
175-184 (1952) ] demonstratedthat vowelsin CVC context are identified
114thMeeting:
Acoustical
SocietyofAmerica
$83
with a very high degreeof accuracyby humanlisteners.A numberof
attemptshavebeenmadeto classifythePetersonandBarneyvowelsusing
somecombination
ofF0 and the threelowestformantfrequencies.
Althoughtheseattemptshavebeenreasonably
successful,
the accuracyof
theclassification
algorithmshasbeenwellbelowthat of humanlisteners.
Humanlisteners,
however,
haveaccess
todynamic( durationandspectral
change)aswellasstaticinformation(F0 and"target"formantfrequencies). The purposeof the presentstudywasto determinethe identifiability
of the Petersonand Barneyvowelsetbasedexclusivelyon staticinformation. A formantsynthesizer
wasusedto generateisolated,steady-state
versions
of all 1520vowels(76 speakers
X tenvowelsX tworepetitions)
inthePeterson
andBarneydatabaseusingmeasured
valuesofF0 andF IF 3.Preliminaryresultsfroma smallgroupoftrainedlisteners
suggest
that
the error rate for the resynthesized
stimuliis 3.5-4.5 timesgreaterthan
the error rate reportedin the original Petersonand Barneystudy.Pilot
dataalsosuggest
thattheidentification
taskmaybeextremelydifficultfor
someuntrainedlisteners.
[Work supported
by RomeAir Development
Centerundercontract• F3060285-C-0008.]
(1987) ]. Acousticanalysis
of thecategorized
syllables
revealednosingle
featurethat couldhave supportedgeneralization,
suggesting
that the
quailusedsomecombination
of stimulusproperties
to categorizesyllables.Currentexperiments
investigate
twowayssucha category
couldbe
formed.First,initialconsonant
informationmaybeevaluatedconditional
uponthevowelthatfollows.Whetherquailcanlearnto categorize
syllablesin which, for example,positiveexemplarsare CVs with eithera
voicedstopanda frontvowel,or a voiceless
stopanda backvowelisbeing
tested.A secondpossibilityis that phoneticcategories
are examplesof
polymorphous
concepts,
with no singlenecessary
or sufficient
condition
for classmembership.
Two birdshavelearneda conceptin whichthree
stimulusdimensions
of syllablesare neededto makea categoryassignment.The bestsubjecthaslearneda conceptthat requiresherto discriminate: (1) voicedversusvoiceless
syllable-initialstops,(2) front versus
backvo?els,and(3) sexofthetalker.Responses
tonovelstimulireveala
categorystructureremarkablysimilarto that hypothesized
for humans.
The fact that quailcanlearna conceptin whichmultiplecuesareclearly
requiredsuggests
that generalmechanisms
of auditionand perceptual
learningare sufficientfor acquisitionof speechcategories.[Work supportedby NICHD. ]
LL25. Vowelandconsonant
judgmentsare notindependent
whencuedby
the sameinformation.D. H. Whalen (HaskinsLaboratories,270 Crown
Street, New Haven, CT 06511 )
Vowelswith ambiguous
formantpatternscanbeperceived
aschanging from [•e] to [5] as durationdecreases.
Similarly,ambiguous
final
consonants
canbeperceived
as [d] whenthepreceding
vowelislongand
It] when it is short. Mermelstein[Percept.Psychophys.
23, 331-336
(1978) ] had subjectsidentifyfour syllables("bad," "bat," "bed," and
"bet") thatweresynthesized
byvaryingonlyvowelduration.He claimed
theconsonant
andvoweljudgmentswereindependent,
implyingdistinct
vowelandconsonant
systems.
The presentreplication
indicates
thatMermelstein'sanalysislackedpowerand that, in fact, thejudgmentsare dependenton eachother:Subjects
weremorelikelyto reporthearing[•e]
and [t ] together,sincemoreof thevocalicsegment
durationisattributed
to thevoweland/or lessisattributedto theconsonant.
Similarly,subjects
are morelikely to reporthearing[•] and [d] together,sincethereis less
duration attributed to the vowel and/or more attributed to the consonant.
Thisindicates
thatlisteners
heara coherent
syllable,in whichtwodistinctionsthatdependonthesameinformationmustcompetefor thatinformation. [Researchsupported
by NIH Grant HD-01994.]
LL28. Qualitative separatenessin children's speech.Susan Nittrouer
(Haskins Laboratories, 270 Crown Street, New Haven, CT 06511 and
Boys Town National Institute, 555 North 30th Street, Omaha, NE
68131) and D. H. Whaien (Haskins Laboratories,270 Crown Street,
New Haven, CT 06511 )
Acousticanalyses
of fricative-vowel
(FV) syllables
spokenby adults
andyoungchildren(ages3 to 7 years)havedemonstrated
severaldifferences.In children'sspeech:( 1) thegrossspectraof/]'/and/s/segments
weremoresimilarthanthoseof adults;( 2 ) fricativeF2 frequencies
varied
moreasa functionofvowelcontext;and(3) therelativeF2 amplitudewas
greater.Theseacoustic
differences
betweenchildren'sandadults'speech
providedan opportunityto testtwocompeting
hypotheses
of perceptual
segmentation.
Accordingtoone,listeners
dividethesignalintotemporally discrete,context-sensitive
allophonesthat can be usedto makeinferencesaboutlater-arrivingsegments.
The second
hypothesis
suggests
that
listenerscan separatesimultaneously
arrivingacousticinformationinto
successive
phoneticunits.In thepresentsetofexperiments,
briefportions
of fricativenoiseextractedfrom FV syllablesspokenby adultsand childrento normaladultlistenerswerepresented.
Resultsshowedthat listen-
LL26. Statisticalrepresentation
of word-initialobstruents:Further data.
Karen Forrest,(3ary Weismet,and Paul Milenkovic (SpeechMotor
ControlLaboratories,
Universityof Wisconsin Madison,Madison,WI
53705-2280)
At the 113thMeetingof theAcousticalSociety,a procedurewaspresentedfor the classification
of word-initialobstruents.
The procedureinvolredcalculatingFFTs at ! O-msintervalsfrom theonsetof theobstruent
throughthe third cycleof the followingvowel.TheseFFTs weretreated
as random probabilitydistributionsfrom which the first four moments
(mean,variance,skewness,
andkurtosis
) werecomputed;
computations
were also made on Bark transformed FFTs. Moments calculated over the
first40 msof voiceless
stopsdiscriminated
placeof articulationwith97%
accuracy.Voiceless
sibilantswerecategorizedwith about98% accuracy
when the Bark transformed moments from the first 20 ms of the fricatives
were used.The speechsampleusedin the previousstudyonly allowed
comparison
ofobstruents
across
twovowelcontexts.
In thisreport,results
of the momentsanalysisof a speechsample are presentedin which all
voicedandvoiceless
stops,aswellasvoiceless
sibilants,arepairedwith six
vowels,/i,a,u,•e,n,e/. The efficacyof the momentsin discriminatingobstruentsin this broadercontextwill be discussed.
[Work supportedby
NIH award NS13274.]
erswerelessaccuratein fricativeidentification
for child speakers,
but
moreaccuratein identifyingthe vowelcontextfrom whichthe fricative
noisecame.Thusthegreatercoproduction
foundin children's
speech
was
moreeasilyrecovered
by listeners,
eventhoughthemostprominentphone
was more poorly perceived.This findingwas taken as supportfor the
secondhypothesis.[Work supportedby NIH GrantsNS-07237and HD01994 to Haskins Laboratories.]
LL29. Recognitionof speechand recognitionof speakersex:Parallel or
concurrentprocesses?
M. O'Kane (School of Information Sciencesand
Engineering,Canberra College of Advanced Education, Belconnen,
A.C.T. 2616, Australia)
If the samephoneticstringis spokenby a malespeakerand a female
speaker,bothdrawn from a linguisticallyhomogeneous
population,then
a listenerperceivesthat both speakersare sayingthe samesoundsbut
generallyknowsthat the speakersare differentand, in particular, that the
speakersare of a differentsex.What is not well understoadis whetherthe
listenerhasto determinethe identityof the sexof the speakerin order to
determinetheidentityof thesounds,or whetherthe two piecesof informationare essentially
independent
andcanbe determinedconcurrently,
Japanesequail.Keith R. Kluenderand Randy L. Diehi (Departmentof
Psychology,
Universityof Texas,Austin,TX 78712)
or whetherthe identityof the soundscanbe roughlydeterminedwithout
knowledgeof the speaker'ssexbut finerecognitionis possibleonly after
the speaker's
sexis known.In thispresentation,
evidencefor andagainst
thesevariouspossibilities
froma largenumberofpsyeholinguistic
studies,
Japanese
quail (Coturnixcoturnix)havelearnedto form a category
for syllable-initiai[d], and candiscriminate[d] syllablesfromthosebeginningwith [b] or [g] acrossvowelcontexts[Kluenderet aL, Science
particularlythosedealingwith varioussex-specific
effectsin a varietyof
languages,
is surveyedand the implicationsfor the designof automatic
speechrecognitionand understanding
systems
are discussed.
LL27, Use of multiple speech dimensions in concept formation by
S84
J. Acoust.Soc. Am.Suppl.1, Vol. 82, Fall 1987
114thMeeting:AcousticalSocietyof America
584
LI30, Effectsof speakergenderon speechrecognition
by hearing
impaired listeners. AngelikaStieren and WinifredStrange
(Department
of Communieology,
University
of SouthFlorida,Tampa,
LL31. Are female voicesmore intelligible than male voices?Florion
J. Koopmans-van Beinum and Mirjam T. J. Tielen (Institute of
PhoneticSciences,
Universityof Amsterdam,Hcrcngracht338, 1016CG
FL 3362(I)
Amsterdam, The Netherlands)
Audiologists
andclients
oftenclaimthatfemale
speech
islessintelligible than malespeech
for subjects
with bilateralhigh-frequency
sensorineuralhearinglosses.
To examinetheextentto whichsourcecharacteristics(voicepitch)andgender-related
resonance
characteristics
contribute
to thesespeechrecognitiondifficulties,two men and two womeneach
produced
threesublists
of themodified
rhymetest(MRT). Withingendergroups,
onespeaker
hada relativelylowvoicepitch,onea highpitch,
suchthatthehigh-pitched
malevoicewasapproximately
thesameasthe
low-pitched
femalevoice.Stimuliwerepresented
to listeners
at 30 dB SL
in quiet,in speechnoise(S/N = q- 12 riB), and in speechbabble(S/
to studythe relativeintelligibilityof maleand femalevoices,ten maleand
ten femalespeakers
wereaskedto readthreephonotactically
balanced
listsof 50 CVC combinations.
Specialcare wastaken with respectto
speech
level,signal-to-noise
ratio,andpresentation
methodusing:equiva-
N = q- 12dB). Overallresultsshowedsignificant
differences
in identifi-
cationofconsonants
across
speakers.
However,contraryto expectations,
performance
wasworstforthemalewiththelowvoicepitch,intermediate
for the two femalespeakers,
and bestfor the high-pitched
male.There
appeared
to begender-related
differences
in thetypeof consonant
errors.
THURSDAY
MORNING,
19 NOVEMBER
Studies
on theintclligibility
of femalecompared
to malevoices,
and
studieson the relationbetweenacousticparameters
(suchasFo) and
speech
understanding
areratherscarce
andindirect.However,particular]y in information-providing
services,
femalevoicesare frequentlyused,
whereas,in speech-technology
applications,they arc often excluded,
probablydueto inadequate
methods
foranalyzingfemalevoices.In order
lent peaklevel,babblenoise,and a variationof the Nakatani and Dukes
method.For a smallnumberof trainedlisteners,
theintelligibilitythresh-
oldperspeaker
isestablished,
providing20 measuring
pointsperlistener.
Furthermore,wordandphoneincintelligibilityperspeakeraremeasured
with phoneticallybalancedsentences
andwords,at a fixedS/N ratio.
1987
TUTTLE
NORTH
ROOM, 9:00 A.M. TO 12:00 NOON
SessionMM. StructuralAcousticsandVibrationIV: ViscoelasticPolymers:Their Descriptionand
Evaluation
Wayne T. Reader, Chairman
Code1905.2,David W. TaylorNavalShipR&D Center,Bethesda,
Maryland20084
Chairman's
Introduction--9:00
Invited Papers
9:08
MM1. Viscoelasticityof polymers•Consideratlonof predictivemethodsfor wide frequencyresponse.
RaymondE. Wetton(PolymerLaboratories
Limited,The Technology
Centre,EpinalWay, Loughborough
LEI 1 0QE, United Kingdom)
Thenatureof viscoelasticity
in highpolymersisdiscussed
in molecularterms.The factorsaffecting
dampinganddynamicmodulus
areoutlined.Manycommercial
polymers
aremultiphase
andthewidthandmagnitudeof molecularrelaxationareshownto be relatedto the compatibilityof the components.
Mastercurves
showing
viscoelastic
response
overa widerangeoffrequency
canbegenerated
usingsemiempirical
procedures
of time-temperature
shiftingof data.The Williams,Landel,and Ferry (WLF) relation,in particular,is
discussed
for multi-andsingle-component
polymers.
In general,predictions
of dynamicresponse
viaextrapolationoveroneor twodecades
in frequency
canbemadewithreasonable
confidence,
if enoughdetailedcareis
taken.The useof dielectriclosspeakloci at highfrequencies
is proposedto aid thesepredictions.
9:30
MM2. Thetemperature
dependence
ofviscoelastie
responses
above
Ts. RobertF. Landel(JetPropulsion
Laboratory, 4800 Oak Grove Drive, Pasadena,CA 911091
Theoriginsof theWLF equation
will bereviewed,
alongwiththeroleof thetemperature
dependence
of
responses
in tryingtoascertain
relaxation
mechanisms.
Somepitfalls,misuses,
andmisunderstandings
will be
described,
together
withsimilarcomments
onso-called
Ts's.Thegeneral
applicability
andutilityofthetemperature
scaling
ofthetimedomainwillbeillustrated
withexamples
fromdamping,
rupturebehavior,
friction,
and crack propagation.
$85
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
114thMeeting:Acoustical
Societyof America
$85
9:55
MM3. Molecularbusisof •he acousticpropertiesof imlyurethanes.
Bruce Hartmann, Gilbert F. Lee, and
JamesV. Duffy (PolymerPhysicsGroup,Naval SurfaceWeaponsCenter,SilverSpring,MD 20903-5000)
Theacoustic
properties
of polyurethanes
asa functionof frequency
aredominatedby a verybroadrelaxationprocess
in whichthepolymermakesa transition
fromtherubberytotheglassy
state.It isconvenient
touse
an analyticrepresentation
of thedatathatexpresses
thecomplexshearmodulus
in theform
G* = G• - (G• - Go)/[l + (itoh')
•] ,
whereGoisthelimitinglow-frequency
modulus,G, isthelimitinghigh-frequency
modulus,r istherelaxation
time,anda is a dimensionless
parameter,with valuesbetweenzeroand one,that determinesthe width of the
relaxation.
It willbeshownthatr isrelatedto theglass
transition
temperature
T• of thesoftsegment
in the
polyurethane.
In turn, T• is foundto depend
on thedegree
of phaseseparation
thatoccursbetween
the
chemicallyincompatible
hardandsoftsegments,
aswellasthedegreeof crystallinitydeveloped.
Thesesame
molecular
factorsdetermineGo,butG, isfoundto beessentially
constant.
Attemptsto relatea to thewidthof
theglasstransitionasmeasured
in a differentialscanning
calorimeterhavebeenonlyqualitativelysuccessful.
[Worksupported
by theNSWC Independent
Research
ProgramandtheOfficeof NavalResearch.
]
10:20
MM4. Techniquesfor noiseand signaturereductionapl•lications.
D. J. Townend(Admiralty Research
Establishment,
Holton Heath, Poole,DorsetBH 16 6JU, United Kingdom)
In recentyears,DMA testsystems
havebecomecommercially
available.Priorto this,workersin thisfielcl
developed
equipment
to meettheirownspecific
needs.Currentcommercial
equipment
isaimedat thethermal
analysismarketandisseenascomplimentary
to established
techniques,
suchasDSC andTMA. Greatemphasisis placedon temperature
control,but,in general,lessattentionispaidto frequencyrangeandmechanical
design.Upperfrequencylimitsare usuallyaround100Hz. While low frequencies
are idealfor the studyof
molecularrelaxationprocesses
and for routinematerialcharacterization,
they havelittle immediateapplication in the fieldof noiseand signaturereduction.Recentwork at ARE hasresultedin the development
of
computerized
WLF technique;thismethodis basedon a referencefrequencyaswell asa referencetemperature.In general(thoughnotessential),thereference
pointselectedisthetemperatureof peaktan at a frequency of I Hz. Wheremultiplexedfrequencydata are available,it is a simplematterto verifythat an unknown
materialwill fit the standardequationby comparingmeasuredshiftsin peaktan with computedvaluesbased
on the standardconstants.Signaturereductionapplicationsrequiresystemsthat, in somecases,work at
frequencies
upto I MHz. Computerized
predictions
basedonWLF data,shiftedfromlow-frequency
measured
data,showverygoodagreementwith high-frequency
measuredacousticdata,but it wouldbe reassuring
to be
ableto measuredynamicmechanicalpropertiesat kilohertzfrequencies.
Recentimprovements
to an inertial
mass,air-bearingsupported
system,developed
at ARE some10yearsago,haveresultedin a systemcapableof
yieldingcomplexshearmodulusdata at frequencies
up to l0 kHz.
10:45
MMS. Experimentalcoml•qson of dynamicmechanicaltestingfacilities at severalNavy laboratories.R.
N. Capps,R. Y. Ting, and M. E. Quinn (Underwater SoundReferenceDetachment,Naval Research
Laboratory,P.O. Box 568337,Orlando, FL 32856-8337)
Dynamic mechanicalspectroscopy
providesvaluableinformationon frequency-dependent
relaxation
mechanisms
in highpolymers.The Young'smodulusandlosstangentare oftenmeasured,dueto the relative
easeof experimental
implementation.
A varietyof techniques
is used,whichoftengivesdifferentresultsfor
samples
that aresupposedly
of thesamematerials.A problemexistsin interpretingsuchresultsin thatonecan
neverbesureif suchdifferences
are dueto measurement
techniques
or to actualmaterialpropertyvariations.
Two systems,an automated resonancetechniqueand the Polymer LaboratoriesDMTA, are now used at
severalNavy laboratories.
To checkthe internalconsistency
of resultsobtainedwith thesesystems,
a "roundrobin"evaluationwasperformed.Commonbatchesof materialsof severaldifferenttypesof rubberswereused
to preparesamplesfor eachof threedifferentNavy laboratories.
The resultsof thistestwill be presented,
and
factorsthat canaffecttheaccuracyandreproducibility
of dynamicmechanicalpropertymeasurements
will be
discussed.
Criteriafor theapplicabilityof themethodof reducedvariableswill alsobetreated.[Work supported by NAVSEA. ]
11:10
MM6. Standardizedpresentation
of complexmodulus.Lynn Rogers(AI•VAL/FIBA•
Wright-Patterson,
Dayton, OH 45433-6553)and Bryce Fowler (CSA Engineering,Inc., 560 San Antonio Road--Suite 101,
Palo Alto, CA 943064682)
The capabilities
of a proposed
standardfor graphicalpresentation
of complexmodulusdatafor viscoelastic
vibration dampingmaterialswill be described.A plot of material lossfactor versusmodulusmagnitudeindicatesdata quality;a frequency-temperature
homogramis includedon this plot, therebyalsomakingit suffi-
cient for the designer.The more typical reducedfrequencyplot is also presented,but with experimental
temperatureandfrequencyrangesgivento assistthe designerin avoidingextrapolationof data.The stateof the
art in modelingtemperatureshiftfunctionsandcomplexmodulususingfractionalderivativeswill bepresented.An interactivecomputerprogramfor processing
a setof complexmodulusdata will bedescribed.A system
to storeand retrieve dampingmaterial data will be described.
S86
J. Acoust.
Soc.Am.Suppl.1,Vol.82,Fall1987
114thMeeting:
Acoustical
Society
ofAmerica
886
11:35
MM7. A computer-based
systemfor representation
of dampingpropertiesof materials.B. L. Burkewitz
(BBN Labs,Inc.,Cambridge,
MA 02138),J. L. Hamer(E-A-R Division,CabotCorp.,Indianapolis,
IN
46268),andC. I. Holmer(NoiseControlTechnology,
Inc.,Reston,VA 22091)
Thedesignofa computer-based
dampingdataanddesignsystem(DDDS) isdescribed.
Importantfeatures
of thesystemare:modularity,standardized
interfaces
betweenmodulesbasedon definedinformationcontent,
easeofexpansion,
physically
basedrepresentation
of materialdynamicmodulus,supportforall usersfromtest
throughanalysis,andqualitycontrolto treatmentdesign.Systemarchitecture
andmodulefunctionaredescribed,followedby a detaileddiscussion
of the materialrepresentation
module.The input for thismoduleis
materialtestdata,andtheoutputisa setofanalyticexpressions
forthefrequency
andtemperature
dependence
of the material.The softwarefor thismoduleis basedon thework of Rogers[J. Rheol.27, 351-372 (1983) ],
whichprovidesa rheologically
consistent
analyticfunctionrepresentation
for the dynamicmodulusandloss
factor.The moduleis writtenwithin RS/l, a table-oriented,
scientificsoftwaresystem.Dampingtreatment
designsoftwareand approaches
to systemdataqualityissuesare alsoaddressed.
THURSDAY
MORNING,
19 NOVEMBER
1987
BRICKELL
NORTH
ROOM, 9:30 A.M.
Meeting of Accredited StandardsCommittee S12 on Noise
to be heldjointly with the
Technical Advisory Group for ISO/TC 43/SC 1 Noise
W. Melnick, Chairman S12
OhioState University,UniversityHospitalClinic,456 ClinicDrive, Columbus,Ohio43210
H. E. yon Gierke, Chairman,TechnicalAdvisoryGroup for ISOfFC 437SC 1
Director,Biodynamics
& Bioengineering
Division,AFAMRL/BB U.S.Air Force,Wright-Patterson
Air ForceBase,Dayton,
Ohio 45433
Standards
Committee
$12 onNoise.Workinggroupchairswill reportontheirprogress
undertheplanfor the
productionof noisestandards.The interactionwith ISO/TC 43/SC I activitieswill be discussed.
S87
J. Acoust.Soc. Am. Suppl.1, Vol. 82, Fall 1987
114th Meeting:AcousticalSocietyof America
•87
THURSDAY AFTERNOON,
19 NOVEMBER 1987
TUTTLE CENTER ROOM, 1:00 TO 3:50 P.M.
SessionNN. PhysicalAcousticsVII: Acousticand SeismicCouplingII: Liquid-Solid Interfaces
Michael A. Schoenberg,
Chairman
Schlumberger-Doll
Research,OM QuarryRoad,Ridgefield,Connecticut
06877
Chairman's Introduction--l:00
Invited Papers
1:05
NNI. Seismic
anisotropy
in theupperoeeanle
erust--Areview.R. A. Stephen
(WoodsHoleOceanographic
Institution, Woods Hole, MA 02543)
Overthepast10years,therehavebeenfourreported
observations
ofseismic
azimuthal
anisotropy
in the
upper2 km of oceaniccrust.The mostprobable
causeof anisotropy
in the uppercrustis the preferred
orientation
of large-scale
fractures
thatarecreated
duringcrustalgeneration
at theoceanridges.Seismic
velocities
are slowparallelto the spreading
directionandfastperpendicular
to it. In someinstances,
clear
azimuthallydependenttravel-timeanomaliesare observedand, in others,thereis evidencefor shearwave
splitting.
At onesite,bothshear
wavesplitting
andtravel-time
anomalies
gaveconsistent
results.
Thechallenge
in all studies,
however,
isto separate
theeffects
of anisotropy
fromtheeffects
of scattering
andlateralhetero-
geneity.
Currentmodeling
capability
isinadequate
toinclude
theeffects
ofbothanisotropy
andheterogeneity
atthescales
observed
intheseafloor.
A definitive
studyontheeffects
ofanisotropy
andheterogeneity
thatwill
determine
whichobservations
arebestforresolving
givenparameters
isneeded.
In addition,
high-quality
threecomponent
seismic
stations
arerequired
to provide
thedataforparticlemotionanalysis.
Thismayrequire
boreholeseismicinstallations.[Work supportedby NSF.]
1:35
NN2. Characterization
of anisotropic
elasticwavebehaviorin mediawith parallelfracturesandaligned
cracks.MichaelSchoenberg
(Schlumberger-Doll
Research,
OldQuarryRoad,Ridgefield,
CT 06877-4108)
Largeparallelfractures
or aligned
microcracks,
whetherfluidfilled,empty,or debrisfilled,cause
specific
typesofmaterialcompliance
increases,
whicharemanifest
in theanisotropic
behavior
of elasticwavesin such
media.
Theanisotropy
attributable
tothefracture
system
maybetriclinic(themostgeneral
) withsixindependentcompliances,
monoclinic
withfour,orthorhombic
withthree,or transversely
isotropic(rotationally
symmetric
fractures)
withtwo.Thefracturesystem
maybeembedded
in ananisotropic
elasticbackground
withno restrictions
on thetypeof anisotropy.
To compute
thelongwavelength-equivalent
moduliof the
fractured
mediumrequires,
at most,theinversion
of two3X 3 matrices.
Dilutesystems
of flataligned
microcracks,
assumed
onaverage
rotationally
symmetric,
inanisotropic
background
yieldanequivalent
medium
of
thesameformasthatof theisotropic
mediumwithlargetransversely
isotropic
fractures;
i.e.,therearetwo
additional
parameters
duetothepresence
ofthemicrocracks
thatplayrolesin thestress-strain
relations
ofthe
equivalent
mediumidenticalto thoseplayedby theparameters
dueto thepresence
of largefractures.
Thus
knowledgeof the total of four parameters
describing
the restrictedtransverse
isotropyof sucha fractured
mediumtellsnothingofthesizeorconcentration
ofthealignedfractures,
butdoescontaininformation
astothe
overallexcesscompliancedue to the fracturesor cracksand their orientation.
2:05
NN3. Borehole
modes
in a fluid-saturated
permeable
medium:
Numerical
andexperimental
results.
Hsuilin LiuandKenneth
W. Winkler(Schlumberger-Doll
Research,
Ridgefield,
CT 06877)
StoneIcy
waves
propagating
inboreholes
inpermeable
materials
provide
a unique
opportunity
tostudythe
boundary
conditions
ata fluid/permeable-solid
interface.
First,a review
ofthetheory
andpresent
frequency
domain
solutions
forStoneley
wavevelocity
andattenuation
ispresented.
Formation
premeability
isshown
to
decrease
theStoneley
wavevelocityandincrease
theattenuation
compared
to thenonpermeable
case.This
effect
ismostpronounced
atlowfrequencies.
Thenthetheory
isapplied
tofinitesizecylinders,
suchasmight
occurin laboratory
experiments.
In thiscase,
twoclasses
ofextensional
modes,
besides
theStoneIcy
mode,are
found.Oneclassisthefastwavemode,whichisanalogous
to theordinaryextensional
mode.The otherclassis
theslowwavemode,
so-called
because
thezeros
arelocated
alongtheBiotslowwavebranch
cut.Fora highly
permeable
medium,
theslowwave
modes
canobscure
theidentification
oftheStoneley
mode.
Alsopresented
is
theexperimental
confirmation
of thenumerical
predictions
for Stoneley
wavepropagation.
Compared
to
conventional
ultrasonic
techniques,
thenewStoneIcy
wavetechnique
allows
theperformance
measurements
in
a broadfrequency
bandabove
andbelowthecriticalfrequency
ofBiottheory.Oneapplication
oftheresults
is
estimating
rockpermeability
using
theborehole
Stoneley
modein petroleum
prospecting.
S88
J. Acoust.Soc.Am.Supph1, Vol. 82, Fall 1987
114thMeeting:AcousticalSocietyof America
$88
2:35
NN4. The effects of azimuthal anisotropyon seismicshear wave data. R. M. Alford (Amoco Production
Research,P.O. Box 3385, Tulsa, OK 74102)
As a resultof seismicfield experiments,
shearpolarizationsplittinghas beenidentifiedas a significant
impedimentto shearwave data quality. The polarizationsplitting,or shearbirefringence,resultswhen a
transversely
polarizedelasticshearwavepropagates
throughan azimuthallyanisotropic
medium.As a consequenceof thisobservation,
the perception
of shearwavepropagation
hasbeensignificantly
alteredandnew
techniques
for acquisition,
processing,
andinterpretation
hasbeendeveloped.
In thispaper,the anomalous
behaviorof the dataisexaminedandtechniques
aredeveloped
to compensate
for theeffectsof shearpolarizationsplitting.The correcteddatareveala time-varyingdelaybetweentwoshearpolarizations,
whichischaracteristicof shearwavepropagation
in an azimuthallyanisotropicmedium.Azimuthalanisotropymayprovide
anotherparameterfor discriminating
rock typesandproperties,and the possibilityof detectingfracturesand
permeability
trends.Therealizationthatshearwavesplittingisanimportantphenomenon
helpsto explainthe
erraticandunpredictable
natureof sheardataquality.New techniques
providean excitingrenewalof potential
for theexploitation
of shearwaveseismic
datain exploration.
ContributedPapers
3:05
NNS. Coupling of sound with surface waves on fluid-loaded elastic
objects describedby a generalizationof GTD. Philip L. Marston
(Departmentof Physics,WashingtonState University,Pullman, WA
99164)
The geometricaltheoryof diffraction(GTD) wasrecentlyextended
to describesurfaceelasticwave (SEW) contributionsof scatteringfrom
fluid-loaded
spheres
andcylindersat highfrequencies
[P. L. Marston,J.
Acoust.Soc.Am. Suppl.1gl, S14 (1987) ]. The couplingoœan
SEW with
theacou:•tic
fieldwasdescribed
by a complexcoefficient
G. That analysis
gavesimplephysicalapproximations:
IGl• 8,r•C/Cswfor spheresand
ian beamrepresentation
is introduced
to replacethe traditionalplanewaverepresentation
sothatthesolution
isananalytical
oneratherthana
symbolic
integral.Thisreplacement
ismadepossible
by a computer
optimizationroutinethat overcomes
problemsintroducedby useof nonor-
thogonalfunctions,
andenables
theexpression
of thefieldsolutionin a
simpleclosed
analytical
form--thesumofGaussian
functions.
Thetechniqueisappliedtothedescription
ofthereflected
fieldofa bounded
beam
incidentat theRayleighanglewith verysatisfactory
results.[Research
sponsored
bytheScience
Alliance,a StateofTennessee
Centerof Excellence.]
]GI• 8•'B/(•rka)•/2forcylinders;
these
wereconfirmed
withothernumericalresults.The SEW angular attenuationcoefficient(due to radiation damping)and phasevelocityare/? and Csw,while c denotesthe
soundspeedin thefluid,k = •o/c,anda istheobject'sradius.The present
work extendsthe originalanalysisofbackscatteredsoundto caseswhere
theSEW onlypartiallycircumnavigates
theobject.If a planesoundwave
ofamplitudepiexcites
anSEWona cylinder,thesoundamplituderadiat-
ed by the SEW aftertravelingan arc lengthL is p•p•(a/2r) •/•
X 1G/21ex
p( - •gL/a). Theobserver
isa distance
r froma virtualsource
(in the cylinder), from whichthe radiatedraysappearto diverge.A simpleapproximation
of/?showsthat/1octheratioof fluidto soliddensities.
Theratioof the]G I forspheres
andcylinders
isconfirmed
bygeometrical
considerations.
[ Work supportedby ONR. ]
3:20
NN6. A Gaussianbeam representationof wave fields at a liquid--solid
interface.J. J. Wen and M. A. Breazeale(Department of Physics,The
Universi.
ty of Tennessee,
Knoxville,TN 37996-1200)
A newmethodof analysisisdescribed
to representthe resultantfield
whena wavebeamissubjected
to anyphysicalprocess(e.g.,propagation,
focusing,reflection,diffraction,etc.). Insteadof expressing
thefieldsolution asa continuousdistributionof planewavesthroughspatialFourier
analysis,a setof Gaussian
beamsisemployedasthebasicunit.The Gauss-
S89
J. Acoust.$oc. Am. Suppl.1, Vol. 82, Fall 1987
3:35
NN7. Saltus-typeboundaryconditionsfor the modelingof rough
interfacesin acousticwaveproblems.AdriannusT. de Hoop, Sijtze
M. de Vries (Facultyof ElectricalEngineering,
Delft Universityof
Technology,
P.O. Box5031,2600GA Delft,The Netherlands),
and
DouglasMiller (Schlumberger-Doll
Research,Old Quarry Road,
Ridgefield,CT 06877-4108)
The methodof movingvolumeaverages
is usedto deriveboundary
conditions
of thesaltusor jump typefor the modelingof acousticwave
interaction
across
a roughinterface
between
twomedia.Forthispurpose,
a smoothboundary
layerisconstructed
thatcontains
theroughinterface
in its interior.The mediumin thislayerisconsidered
asa mixtureof the
twomediapresent.
On thescaleat whichtheacoustic
wavemotionis
analyzed,
themixtureisassumed
tohaveacoustically
linearmacroscopic
properties.
The resulting
saltus-type
boundary
conditions
express
the
jumpsin thebasicquantities
thatdescribe
thewavemotion(pressure
or
stress
andparticlevelocity)
across
theboundary
layerin termsof the
limitingvalues
thatthese
quantities
attainat eithersideof thelayerin a
linearmanner.Conditions
of thistypeareworkedoutfor a roughinterfacebetween(a) twofluids,(b) twosolids,and (c) a fluidanda solid.In
allcases,
fullanisotropy,
including
theonethatisinduced
bytheinterface
geometry,
is takenintoaccount.
114th Meeting:AcousticalSocietyof America
S89
THURSDAY AFTERNOON,
19 NOVEMBER 1987
UM AUDITORIUM,
1:00 TO 4:15 P.M.
Session00. SpeechCommunicationVI: Focus Sessionon the Female Voice
Caroline G. Henton, Chairman
Linguistics
Program,University
of California--Davis,Davis,California95616
Invited Papers
1:00
OO1. The femalevoiceExperiments and overview.Gunnar Fant, ChristerGobl, Inger Karlsson,and
QiguangLin (Department
of Speech
Communication
andMusicAcoustics,
RoyalInstituteofTechnology
( KTH ), Box 70014, S-100 44, Stockholm,Sweden)
Resultsfromrecentexperiments
at theKTH directedtothestudyof aerodynamics
andvoicesourceflow
will bepresented.
Theseincludesimultaneous
recordings
of glottalairflowandsupraglottal
pressure
froma
Rothenberg
mask.A numberof females
served
assubjects
producing
isolated
syllables
and,in oneinstance,
complete
sentences.
For onesubject,
thesubglottal
pressure
wasalsorecorded.
Typicaltemporalprofiles
of
these
measures,
including
glottalleakage,
willbediscussed.
In a separate
study,datawerecollected
onglottal
flowwaveforms
frominverse
filteringofthespeech
pressure
wave.A parametrization
andresynthesis
in terms
of thefour-parameter
LF modelhasbeenundertaken,
whichallowsa comparison
witha setof malevoices.
Theoretical
studies
of source-vocal-tract
interaction
effects
providea basisfor interpretation
of resultsand
modeling
offemalespecific
characteristics.
Finally,a reviewispresented
ofaccumulated
insightin thepropertiesof femalespeechincludingfactorsotherthan sourcemechanisms.
1:30
002. Glottalairflowandpressure
measurements
forfemaleandmalespeakers
in soft,normal,andloudvoice.
E.B. Holmberg,R. E. Hillman (ResearchLaboratoryof Electronics,36-525, Massachusetts
Instituteof
Technology,
Cambridge,
MA 02139andDepartment
of Communication
Disorders,
BostonUniversity,
Boston,MA 02215), andJ. S. Perkell(ResearchLaboratoryof Electronics,36-525, Massachusetts
Institute
of Technology,Cambridge,MA 02139)
Measurements
ontheinverse
filteredairflowwaveform
(the"glottalwaveform")
andofestimated
average
transglottal
pressure
andglottalairflowweremadeforproduction
of syllable
sequences
in soft,normal,and
loudvoiceby20femaleand25malespeakers.
Statistical
analyses
showed
that,whiletherewasnosignificant
female-male
difference
in pressure
withinanyof theloudness
conditions,
thereweresignificant
female-male
differences
in theglottalwaveformparameters
thatshouldberelevantto differences
in voicesourcecharacter-
istics.In normalandloudvoice,femalewaveforms
indicatedlowervocalfoldclosingvelocity,lowerac
(modulated)
flow,andproportionally
shorter
closed
phase
ofthecycle,suggesting
a steeper
spectral
slope
for
females.
In softvoice,femaleacflowwassignificantly
lowerthanmales',buttherewerenosignificant
differences
in female-male
closing
velocityor relativelengthof theclosedportion,suggesting
moresimilarspectral
slopes.
Thedc (unmodulated)
flowdidnotdiffersignificantly
between
females
andmales.
Possible
implicationsof theresultsfor femaleandmalevoicequalityarediscussed.
[Work supported
by NIH.]
2.'OO
003. Physiology
of the femalelarynx. Ingo R. Titze (VoiceAcousticsand Biomechanics
Laboratory,
Department
ofSpeech
Pathology
andAudiology,
University
ofIowa,IowaCity,IA 52242andTheRecording
andResearch
Center,The DenverCenterfor thePerformingArts, 1245ChampaStreet,Denver,CO 80204)
Anatomically,thefemalelarynxdiffersfromthemalein vocalfoldlength,thickness,
angleof thethyroid
laminae,restingangleof theglottis,verticalconvergence
anglein theglottis,anda numberofotherways.The
vocalfoldtissueitselfdifferswithrespect
to thethickness
of themueosaandfibercomposition,
e.g.,theratioof
connective
tissue
to muscle
tissue.
Biomechanically,
it hasbeenfoundthatthestress--strain
curves
areslightly
morelinearin females
thanmales.Based
onthese
andotherknowndifferences
in morphology
andviscoelastic
properties,
a scalingprocedure
isattempted
for fundamental
frequency,
intensity,andotheracoustic
properties.Somerationaleisgivealsoforwhyfemales
develop
pathology
at differentsitesin thelarynx,givenwhatis
currently known about mechanicalstressin the tissues.
S90
J.Acoust.
Soc.Am.Suppl.
1,Vol.82,Fall1987
114th
Meeting:
Acoustical
Society
ofAmerica
S90
2:30-2:40
Break
2:40
004. Factandfictionin thedescription
of femaleandmalepitch.CarolineG. Henton(LinguisticsProgram,
Universityof California,Davis,Davis,CA 95616)
Femalespeech
hasbeencharacterized
ashighpitched,
shrill,overemotional,
and.swoopy.
Pitchis, of
course,a relativescale,soit wouldbe equallyvalidto describe
malepitchaslow pitched,rumbling,underexpressive,
andmontonous.
But if "swoopiness"
is inherentin femalespeech,
it mustbeaskedwhetherthe
effectisoneof a comparatively
widerrange,of greaterdynamicity,
or of a simplearithmetical
misinterpretation.It maybethecasethatprevious
accounts
havebeenbased
onabsolute
(linear)and,therefore,
misleading
valuesin Hertz;whereas
theuseofthesemitonal,
andthusperceptually
moreappropriate,
scale,indicates
that
female
speech
should
notbesomarkedonacoustic
bases
alone.Reexamination
ofpitchranges
anddynamieity
valuesreported
byothersleadsto therejection
of someof theelements
of thestereotype.
Newdataassembled
fromfivemalesandfivefemales
alsoindicatethat,auditorily,femalespeech
contains
similarratiosof pitch
rangein relationto long-term
average
pitch,asdoesmalespeech.
Monotonicity
andreduced
pitchrange,as
important
ingredients
in enhancing
stereotypical
masculine
speech
(Terrangn,1974;BennettandWeinberg,
1974), are reexamined.
3:10
005. Acousticcorrelatesof breathiness:First harmonicamplitude,turbulencenoise,and trachealcoupling.
DennisH. Klatt (Room 36-523, Massachusetts
Instituteof Technology,Cambridge,MA 02139)
A selected
sampleof reiterantspeech
hasbeencollected
fromtenfemalespeakers
andsixmalecontrols
in
orderto quantifyacoustic
correlates
of perceived
breathiness
of thefemalevoice,andto contrastthesemeasureswithcomparable
datafrommales.Twosentences
withdifferingstress
patterns
werespoken
byreplacing
eachsyllable
by [hV] andby [•V], whereV = [a,i,ae,o,rr].Detailedanalysis
ofthe [a] datareveals( 1) wide
variationin thestrengthof thefirstharmonic(relativeto firstformantamplitude),withanaverage
increase
of
about6 dB for femalesrelativeto males;(2) a greatertendencyfor the third formantto be excitedby noise
ratherthanvoicingharmonics
in thefemalepopulation;
and(3) indications
oftrachealpolesandzerosin the
spectraof vowelsadjacentto voiceless
consonants
in utterances
producedby bothgenders.
Thesethreemeasuresofbreathiness
tendto begreatest
in unstressed
syllables
andtowardtheendofan utterance.
The acoustic
datawill becorrelated
withperceived
breathiness
ofutterances
fromindividualtalkersina preliminaryattempt
to determinewhichmeasureis perceptually
mostsalient;futureresearch
usingsynthesis
will systematically
investigate
perceptual
sallenee.
[Worksupported,
in part,by an NIH grant.]
3:40-4:15
DISCUSSANTS:
Sandra F. Disner
R. A. W. Bladon
THURSDAY
AFTERNOON,
19 NOVEMBER
1987
UNIVERSITY
LECTURE HALL, 1:15 TO 4:00 P.M.
SessionPP. Psychologicaland PhysiologicalAcousticsVII: Masking and Detection
Murray F. Spiegel,Chairman
Bell Communications
Research,435 SouthStreet,Room 2E-252, Morristown,New Jersey07960
ContributedPapers
1:15
PPI. Profile analysiswith time-varying stimuli. David M. Green and
Quang T. Nguyen (PsychoacousticsLaboratory, Department of
Psychology,Universityof Florida, Gainesville,FL 32611)
Det•mtinga changein spectralshape,when the changeoccursat a
singlespectrallocus,requiresa simultaneouscomparisonof the unchangeqpart of the spectrumwith the alteredor "signal"part. What are
thetemporal
parameters
ofthestimulus
thatipfiuence
suchcomparisons?
To considerthisquestion,a complexof 2l-equal-amplitude
components
$91
J. Acoust.Soc. Am. Suppl.1, Vol. 82, Fall 1987
wasused,rangingfrom 200-5000 Hz, with equallogarithmicspacing
betweencomponents.
The signalwasan increase
in levelof onecomponentof themulticomponent
spectrum.Overalllevelof thesoundvaried
randomlyovera 20-dBrange.Thesignalcomponent
andthe20nonsignal
components
wereamplitudemodulatedseparately.
The relativephaseof
the two modulatorswas manipulatedso that the signaland nonsignal
components
waxedandwanedeitherin-phaseor out-of-phase.
For modulation rates faster than about 40 Hz, the thresholdsin the two conditions
arenearlythesame.Thus,for slowerratesof modulation,thedatasuggest
that thetemporalstructureof the spectrumis important,whileabove40
114th Meeting:AcousticalSocietyof America
$91
Hz, onlythepowerspectrum
of thestimulusis critical.[Research
supportedby theNationalInstituteof HealthandtheAir ForceOfficeof
ScientificResearch.]
1:30
PP2. Masker envelopesand simultaneous-masking
psychophysical
tuning curves. Todd W. Fortune and David A. Nelson (Hearing
Research
Laboratory,Universityof Minnesota,2630UniversityAvenue
S.E., Minneapolis,MN 55414)
Recentreportsdemonstrate
thatthetemporalenvelope
of a masking
stimuluscaninfluenceitseffectiveness.
To examinethe probableeffectsof
maskcrenvelopeon psychophysical
measures
of tuning,simultaneousmaskingpsychophysical
tuningcurves(PTCs) wereobtainedfrom two
normal-hearing
listeners.The probewasa 250-msl-kHz toneburstpresentedat 60 dB SPL, whichwastemporallycenteredwithin the 500-ms
maskors.MaskorsincludedSAM and QFM tones,narrow-bandnoise,
and puretones.PTCswereobtainedin quietandin the presence
of a
continuous broadband noise to mask combination tones. Results indicate
that fluctuatingenvelopemaskersare lesseffectivethan flat envelope
maskers
onlyon thelow-frequency
sideof the PTC. Thesedatasuggest
thatthelistenerisableto listenfor thepresence
of a probeduringperiods
of low maskerenergy.Four of thesixmaskersinteractedwith theprobe
producing
audiblecombination
tonesthatcouldbemasked
bythebroadbandnoise.Combination
tonesweremostpronounced
for theQFM and
pure tonemaskers,
whichhavesimilarenvelopes.
The significance
of
thesedatawill bediscussed
in termsof frequency
andtemporalresolution,
particularlywithregardto thehearing-impaired
population.[Work supportedby NINCDS. ]
whichthe 295-mssignalintervalwaspreceded
andfollowedby 295-ms
presentations
ofa sinusoid
at thesignalfrequency.
These"fringe"componentshadthesamephaseonall presentations;
thesignalwasaddedto the
maskerin quadrature.Signalthresholdwasmeasuredasa functionof the
phaseanglebetweenthe fixedfringecomponents
andthemasker.In non-
signalintervals,
themaskerandsignalwerereplaced
bya presentation
of
thefringecomponent.
Presentation
ofthesignalthusproduced
a change
in both phaseand levelcomparedto the fringecomponents.
However,
thresholds
werenotimproved
bythepresence
of thephase
change.
Both
of theaboveconditions
wererepeated
fora 20-msmaskerandsignal,and
againshowed
noevidence
thata change
in phaseimproves
detection
performance.
With thisshortersignal,it waspossible
toexaminethreshold
as
a functionof the phaseanglebetweenthe signalanda 295-msforward
masker.In forwardmasking,phasehadno effecton signalthreshold.
[Researchsupportedby NSF.]
2:15
PPS.Maskingof shorttoneburstsof frequency
sweeps.
DavidA. Fabry,
Margaret F. Cheesman(Department of CommunicationDisorders,
Universityof Minnesota,Minneapolis,
MN 55455),Neal F. Viemeister,
and Dean Schei(Departmentof Psychology,
Universityof Minnesota,
Minneapolis,MN 55455)
Maskedthresholds
for a shortprobetoneare greaterfor sweep-frequencytonalmaskersthan for stationarysinusoidal
maskersat equal
SPL,andgreatest
forsweep
ratesof 20-30oct/s [G. F. Smoorenburg
and
F. Coninx,HearingRes.3, 301-316 (1980)]. The presentstudyexaminedpossible
explanations
for thissurprising
phenomenon
and concentratedon theeffectsof maskerlevelon probethreshold.Maskedthresholdswereobtainedfor a 10-ms,l-kHz tonetemporallycenteredin the
100-ms
masker.
Themaskers
weresweptinfrequency
atratesof0-80 oct/
1:45
s and passedthrough I kHz at 50 ms. At the lower maskerlevels,maxi-
PP3. Tuning curve widths of infants and adults in simultaneous and
mummaskingoccurredat sweepratesof 15-25 oct/s. At higherlevels,
little influence
of sweeprateon maskedthresholds
wasseen.Although
nonsimultaneousmasking. Nancy BensonSpctncr and Lynne
WernerOlsho(Departmentof Otolaryngology,
R.L-30,Universityof
Washington,Scattic,WA 98195)
Tuning curve widthswcrc estimatedusingthe pulsationthreshold
(PT) technique
for infants,6-month-olds,
andadults.The observer-based
psychoacoustic
procedure[L. W. Olshoet al., Der. Psychol.,in press
(1987) ] wasthe testprocedure.Listenersdiscriminated
a train of alternatingmaskerand probetoneburstsfrom a train of maskertonebursts
presented
with a continuous
probetone.Thesestimuliwerepresented
in a
background
of broadbandnoiseat 20-dBpressure
spectrumlevel.The
probelevelwas10dBSL.PTswereobtainedat thetuningcurvetip andat
twopoints,oneaboveandonebelowtbeprobefrequency,10dB abovethe
tip. The resultingQ•oswerecomparedto thoseobtainedin simultaneous
maskingfor 6-month-oldsand adults[L. W. Olsho,Inf. Behar.Dev. 8,
371-384 (1985)]. Adult Q•osweresignificantly
greaterfor PT tuning
curvesat 500, 1000, and 4000 Hz. Infant PT •loS were significantly
greaterthan simultaneous
maskingQ•osat 500 and 1000Hz, but not at
4000 Hz. [Work supportedby NIH.]
thereweresubstantial
individualdifferences
in slopes,
the growth-ofmasking
functions
hadslopes
lessthanonewithminimum
slopes
at20-25
oct/s.Theshallowslopes
area distinguishing
featureof sweep-frequency
maskingandmayprovidea basisfor understanding
thisimportantphenomenon.[Supportedby NINCDS grant NS12125and SSHRC-Canada.]
2:30
PP6. Tonal prominenceeffects on annoyanceratings for business
equipmentspectra.G. R. Bienvenue(State Universityof New York,
Collegeat New Paltz, New Paltz, NY 12561), M. A. Nobile, and A.
C. Balant(IBM Acoustics
Laboratory,Poughkeepsie,
NY 12602)
Dayton, OH 45435)
Whilerecentresearchers
havereportedAppendixB ofANSI S12.101985to "workwellin over80% of cases"
andto be"a vastimprovement"
overtheearliermethod,therearetwonotabledifficulties
in itsimplementation.First,whentwo"audiblyprominent"tonesoccurcloselytogether
withina singlecriticalband,theyarcratedas"notaudiblyprominent"by
the presentAppendix,thoughthey producean audibleevent.Second,
certainsharplyfallingnoisespectra
could,bytheupwardspread
ofmasking, maska tonethat is "audiblyprominent."In this case,an inaudible
tonewouldberatedasprominent.
Forthepresent
study,15subjects
were
presented
with tape recordedsoundsof varyingtone-noiseensembles
designedto explorethesephenomena.Subjectsrated thesesoundsfor
Thresholdsfor sinusoidalsignalsat 0.5, 2.0, and 6.0 kHz were measuredin a varietyof maskingconditionsusinga two-interval,forced-
dataarediscussed
withspecialattentionto theirrelevance
forimplementingAppendixB of ANSI S12.10-1985.[ Worksupported
by IBM Corpo-
choiceprocedure.All conditionswereperformedin the presence
of a
diotic,white,broadbandnoisewith a spectrumlevelof 20 dB SPL. All
sinusoidalstimuliwerepresented
monaurallyin the listener'sleft car;all
fixedlevelcomponents
werepresented
at 65 dB SPL. In a determination
of theWeberfractionfor a 295-mssignalmaskedby a sinusoldof thesame
frequencyand temporalcharacteristics,
the thresholdvaried with the
phasebetweenmaskerandsignal,asonewouldpredictfrom theassumptionthattbetaskdepends
onlyuponthedetection
of a difference
in power
(or relateddimension)betweenmaskcrand maskcrplussignal.In these
data,thedetectionof phasedifferences,
perse,appearedto haveno effect
on threshold.Thesedata provideda referencefor a secondcondition,in
ration.]
2:00
PP4. Phase has no effect on simultaneous or forward masked thresholds.
DanielL. Weber(Departmentof Psychology,
Wright StateUniversity,
S92
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
their levelsof loudness,tonal prominence,and annoyance.The research
2:45
PP7. Modeling subjectresponses
in a reproduciblenoisemaskingtask. R.
H. Gilkey and T. A. Meyer (Signal Detection Laboratory,Central
Institute for the Deaf, Saint Louis, MO 63110)
Gilkey and Robinson[J. Acoust.Soc.Am. 79, 1499-1510 (1986)]
modeledsubjectresponses
to individualreproducible
noisesamples,
ran-
114thMeeting:Acoustical
Societyof America
S92
domly selectedon each trial from a set of 25, in a diotic tone-in-noise
detectiontask. They found that a detectorcomposedof a 50-Hz-wide
single-tuned
filtercenteredat the 500-Hzsignalfrequency,
a nonlinearity,
andan integratorwith a 100-to 200-msdecayconstantpredictedthedata
relativelywell. Here, a set of 150 noisesampleswas used,and a more
detailedanalysisof the parameterspaceof the detectorwasperformed.
The resultsof this studyare similar to their results,althoughthe bandwidthsol'the filtersare smaller(26-49 Hz) and the decayconstantsare
shorter(39-100 ms). "Spectralweightingfunctions"werederivedfrom
linearcombinations
of the outputsof sevendetectors,eachat a different
centerfrequency.Thesefunctionsare moreconsistent
than thoseof Gilkey and Robinsonand alsoindicatethat subjectscompareinformation
acrossfrequencyregions.Thesefunctionscan bedescribedasthe differencebetweentwo Gaussian-shaped
weightingfunctions.[Supportedby
NSF and AFOSR. ]
the second
patternare monotonically
decreasing,
whereasthosein the
thirdpatternaremonotonically
increasing.
Sixexperimental
conditions
areexamined,obtainedbyvaryingthefrequency
separation
betweencomponentsandpatterns.The conditionwith thegreatestfrequencyseparation isonein whichthereis a one-fourthoctavegapbetweenpatterns;the
conditionwith the leastfrequencyseparationis one in which all four
patterns
arecomposed
froma singlesetoffrequencies.
Exceptforthelast
condition,successive
patternswithineachconditionarecenteredaround
700, 1000,1400,and2000 Hz, respectively.
Subjects'performance
in the
recognition
taskis at the levelpredictedon the basisof their detection
performance,
in thoseconditions
with greaterfrequency
separation
betweenpatterns.
Recognition
performance
fallsbelowthepredicted
level
in thoseconditions
withlittleor nofrequency
separation.
[Research
supportedby AFOSR.]
3:00
3:30
PPS. Detection of infratonal repetition of frozen noise: Singularity
recognition or linttern recognition? Brad fl. Brubaker and Richard
PP10. Forced-choiceprocedurescan yield contaminatedthresholds:
Musket resl•onsebias. Murray F. Spiegel (Bell Communications
M. Warren (Department of Psychology,University of Wisconsin-
Research,435 South Street, Morristown, NJ 07960)
Milwaukee, Milwaukee, WI 53201 )
Listenerscanreadilydetectiterationof "frozen"Gaussiannoisesegmentswith durationsupto I s IN. GattmanandB. Julesz,J. Acoust.Soc.
Am. 35, 610 (1963) ]. Is detectionof repetitionof thesecomplexwaveformsbaseduponrecognitionof the reoccurrence
of uniquefeaturesor
singularities,
or upona moreholisticrecognition
of thepatternformedby
theseevents?
To answerthisquestion,frozennoisesegments
weredivided
into threesectionsof equalduration(A, B, C) that werereassembled
and
thenrepeatedto form two periodicsounds(ABC), and (ACB),. This
manipul•tionchangedthe temporalarrangementbetweensectionsbut
preservedsingularitiesand repetitionrate. Untrainedlistenersheard a
seriesof sequence
burstsconsisting
of eitheronearrangement
[ (ABC),,
(ABC),,.(ABC) ..... ] or two alternating arrangements[(ACB)•,
(ABC)•,.(ACB) ..... ] and judged whether successive
burstswere the
sameor different.Discriminationwaspossiblewhenthe durationof the
entireiteratedpattern(A 4- B •- C) was900msor less,indicatingthata
holisticrecognition
of patternsoperatesup to thelimit of echoicstorage.
[Work supported
by AFOSR.]
Earlymeasurements
ofhumanperformance
wereplaguedbyresponse
biases,suchasa preference
for choosing"yes"in a yes/nosignal-detection task, or a tendencyto choosethe secondof two soundsas louder,
longer,or higher.Signaldetectiontheory,as well as forced-choice
and
adaptiveprocedures,
have largelyeliminatedthe influenceof response
biaseswhile alsostreamliningthe data collectionprocess.Theseproceduresareadequatewhenthe setof maskersareindistinguishable.
However,adaptiveprocedures,
whencombinedwith forced-choice
methods,
are sensitiveto response
biaswhenthe variousmaskersare distinguishable. The responsebias is a preferencefor particularmaskers,when
maskersare randomizedwithin a trial. Thresholdscan be seriouslycon-
taminated;depending
onthemagnitudeof thebias,subjects
canappearto
be responding
perfectlyto inaudiblesignals.Procedures
that avoidthe
problemresultingfrom thisformof response
biasare not asefficientas
adaptive,forced-choice
procedures,
and often entail more traditional
methodsof testing.
3:45
3:15
PP9. Detectionandrecognitionof complexstimuli. David A. Ansleyand
PPll. A context-free rubber band model of scalingauditory dimensions.
Irwin Pollack (Mental Health Research Institute, University of
DanielL. Weber(Departmentof Psychology,
WrightStateUniversity,
Michigan,Ann Arbor,MI 48109)
Dayton, OH 45435)
Greenet al. [J. Acoust.Soc.Am. 62, 948-954 (1977) ] havedemonstratedthat a subject'sability to detectoneof m possiblesignalsin a yes/
notaskcanbeusedto predictthesubject's
abilityto identifywhichof the
m possible
signalswaspresentwhenthe signalsare four sinusolds
well
separatedin frequency.This studyexaminesdetectionand recognition
whenthesignalsarefourcomplexstimulipresented
againsta background
of white noise(spectrumlevel20 dB SPL). Eachcomplexstimulusconsistsof a temporalsequence
of sevensinusolds.
Each sinusolddiffersin
frequency
fromtheotherswithina pattern,andeachispresented
for 100
msat the samesensation
level.The patternsdifferin the sequence
of the
frequencies
of thecomponent
sinusolds.
For example,thefrequencies
in
$93
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
Auditorysignalsvaryingin frequency,duration,and/or amplitude
werepresented
tolisteners.
Thelistener's
taskwastomarka linearscaleto
ratethe relativepositionof onesoundon a scaledemarkedby theother
two.The signalsthatdefinedtheendsof thescalewerevariedfromtrialto-trial.Theratingsarewell-predicted
byassuming
thattheratioof scale
distances
is invariantwith the particularsoundsthat definethe scale.
Statedotherwise,theratingscaleisconceived
in termsof positions
upona
rubberband. Different scales,definedby differentend stimuli, resultin
localcompression
andextension
of theband,butrelativedistances
among
intermediate
ratingsareunchanged
by scalechanges.
The model'sapparentlyexcellentperformance
may simplyresultfrom the powerfulconstraintof monotonicity
in thescalingof unidimensional
signals.
114thMeeting:Acoustical
Societyof America
S93
THURSDAY AFTERNOON, 19 NOVEMBER 1987
BRICKELL NORTH ROOM, 1:30P.M.
Joint Meeting of AccreditedStandardsCommitteesS1 and S3
Theactivities
ofSl willbediscussed
first,proceeding
tomatters
ofinterest
tobothSl andS3,andconcluding
with S3 activities.
Meeting of Accredited Standards Committee S1 on Acoustics
D. Johnson, Chairman S l
Larson-Davis Laboratories, 280 South Main, Pleasant Grove, Utah 84062
Standards
Committee
Sl onAcoustics.
Workinggroupchairswillreportontheirprogress
in thepreparation
of
standards,
methodsof measurement
andtesting,andterminology
in physicalacoustics,
electroacoustics,
sonics, ultrasonics,and underwatersound.Work in progressincludesmeasurementof noisesources,noise
dosimeters,
integrating
sound-level
meters,andrevisionandextension
of soundlevelmeterspecifications.
Opendiscussion
of committeereportsisencouraged.
Meeting of Accredited StandardsCommittee S3 on Bioaeousties
L. A. Wilber, Chairman S3
422 Skokie Boulevard, Wilmette, Illinois 60091
Standards
Committee
S3onBioaeoustics.
Thecurrentstatus
ofstandards
underpreparation
willbediscussed.
In addition
to thosetopics
of interest
including
hearing
conservation,
noise,
dosimcters,
hearing
aids,etc.,
consideration
willbegiventonewstandards
whichmightbeneeded
overthenextfewyears.
Opendiscussion
of
committeereportsis encouraged.
Theinternational
activities
in ISO/TC 43 Acoustics
andIEC/TC 29 Electroacoustics,
for whichS1andS3
serveastheU.S.TechnicalAdvisoryGroups(TAGs), will bediscussed.
TheChairsof theTAGs for ISO/TC
43 (H. E. vonGierke)andIEC/TC 29 (V. Nedzelnitsky)
will reportoncurrentactivities
of theseTechnical
Committees.
THURSDAY
AFTERNOON,
19 NOVEMBER
1987
POINCIANA
ROOM, 1:30 TO 2:45 P.M.
Session
QQ. Educationin Acoustics
II: Educationvia SatelliteandVideoTapes
Lawrence A. Crum, Chairman
NationalCenter
for Physical
Acoustics,
P.O.Box847, University,
Mississippi
38677
Invited Papers
1:30
QQ1. A satelliteclassroomfor advancedacousticstudies.Richard Stern (Applied ResearchLaboratory,
PennStateUniversity,P.O. Box 30, StateCollege,PA 16804)
The GraduateProgramin Acoustics,
PennStateUniversity,isofferinga Masterof Engineering
Degreein
Acoustics
viasatellite
totheNavyUndersea
Weapons
Engineering
Station(NUWES), KeyportlWashington.
Theprogramwill take2 yearstocomplete
andconsists
of bothtelevised
andon-siteinstruction.
Progress
of the
programand lessonslearnedwill be discussed.
1:55
QQ2. Grsduatecontinuing
education
by satellite.LionelV. Baldwin(NationalTechnological
University,
P.O. Box 700, Fort Collins, CO 80522)
Progress
in telecommunications
technologies
presents
theengineering
profession
withexcitingnewwaysto
integrate
advanced
studywiththejob.TenyearsagotheU.S.colleges
ofengineering
thatoperateregionalITV
systems
startedplanningfor a commongoal:to increase
thenationaleffectiveness
of continuing
education
of
engineers.
Two newinstitutions,the NationalTechnological
University(NTU) and the Associationfor Media-BasedContinuingEngineering
Education(AMCI•E) that coordinatecreditand continuingeducation
programs,respective]y,
are now accelerating
the introductionoœlinkagesbetweenengineering
facultyand
S94
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
114thMeeting:
Acoustical
Societyof America
S94
engineers
atworkviaasatellite.
BothNTU andAMCEEbegan
regular
satellite
delivery
ofadvanced
technical
education
in August1985.Asweenterthethirdyearofoperations,
NTU willservemorethan3200enrollees
foracademic
creditinstruction
during1987-1988;
AMCEE willprovide
overa thousand
hoursof noncredit,
live-and-interactive
programming.
Theservice
operates
in GSTAR-Iwitha modern
Kubandtransponder,
whichbroadcasts
twochannels
offull-motion,
colorvideothroughout
thedayandevening
ofeachworkday.
Eighteen
universities
currentlyoperate
uplinksto provideliveprogramming
overthenetworks
and,in addition,threecorporate
studios
haveuplinksandregularly
originate
instruction.
2:20
QQ3.Usingvideotapes
andaudiotapesonandoffthecampus.
Thomas
D. Rossing
(Department
ofPhysics,
Northern Illinois University,DeKalb, IL 60115)
Theuseofprerecorded
presentations
offersseveral
advantages
to theteacher.Oneof themostattractiveis
topresent
demonstrations
ofacoustical
phenomena
thataredifficult
toimplement
inrealtime,especially
ina
remoteclassroom.
Anotheristosubstitute
animated
textforstilltext(theso-called
"animated
blackboard").
Excerptsarepresented
fromseveralaudioandvideotapesandhowtheycanbeusedto enhance
acoustics
instructionbothon and offcampusis discussed.
THURSDAY
AFTERNOON,
19 NOVEMBER
1987
BOUGAINVILLEA
ROOM, 1:30 TO 4:05 P.M.
SessionRR. Engineering AcousticsIV: Transducers,Waveguides,and Structures
TheodoreA. Henriquez,Chairman
UnderwaterSoundReferenceDetachment,Naval ResearchLaboratory,P.O. Box 8337, Orlando,Florida 32856
Chairman's
Introduction--l:30
ContributedPapers
2:05
1:35
RRI. Diistortionlesspiezoelectrictransducerswith nonuniformelectroelasticparameters.
Dov HazonyandSustoR. Raya (Departmentof
Electrical Engineeringand Applied Physics,Case Western Reserve
University,Cleveland,OH 44106)
RR3. Interpretingpiezoelectricoscillatordissipationeffectsin termsof
the underlying materials viscoelastic relaxation phenomena. R.
Lowell Smith (Texas Research Institute, 9063 Bee Caves Road, Austin,
TX 78733)
Ofcc.nccrnare the generationand detectionof soundby piezoelectric
Equivalentcircuit modelinghas long beenrecognizedas a valuable
transducers
withnonuniform
materialproperties
alongtheprincipalaxis.
It is shownthat subjectto conditionsof distortionless
propagationIV.
tool for describing
transduction
processes
and the behaviorof trans-
Burke,R. $. Duffin,and D. Hazony,"DistortionlessWavePropagationin
Inhomogeneous
Media andTransmission
Lines,"Q. Appl. Math. 183194(July 1976)] it ispossible
to associate
a circuitmodelwiththetransducer similar to the Mason model [W. P. Mason, Electromechanical
Transducersand WaveFilters (Van Nostrand, New York, 1948) ]. This
work foillowsthe developmentof sphericalshellpiezoelectrictransducers
[D. Hazony, "Nonuniformly PoledSphericalShell PiezoelectricTransducers,"J. Acoust.Soc.Am. 81, 1624-1627(1987)]. [Work supported
in part by Tecsonics,
Inc.]
1:50
RR2. Optimizing the performanceof piezoelectricdrivers usingstepped
horns. A. Bangviwatand R. D. Finch (Department of Mechanical
Engineering,
Universityof Houston,Houston,TX 77004)
ducers.
Theformalism
hasbeen
generalized
torepresent
distribute.
dproperties,modecoupling,andtheimplications
of structuralcomplexity,mechanicalloading,and electricaltuning.Dissipationor lossphenomena
canalsobe accommodated
by equivalentcircuitmethods.It is generally
recognized
thatinterpreting
all relevantelastic,dielectric,andpiezoelectric coefficients
as complexnumbersis an appropriateway to represent
losses.All toooften,the scopeof thisapproachdiscourages
the development of detailedresults.This paperanalyzesthe dissipationmodeling
problemin termsof relaxationprocesses,
a phenomenological
approach
that givesalgebraicform to certaingroupings
of the electromechanical
coefficients.
The implicationis that soundspeed,couplingcoefficients,
materialsmoduli,etc., are frequencydependent.A mass-loaded
longitudinalvibratorwith a segmented
piezoelectric
cylinderis analyzedasan
exampleof thismodel-parameter
dispersion
problem.Of particularinterest is the effectof the adhesivejoints on the oscillatoradmittancespectrum overa wide rangeof frequencies.
An analysisispresented
for thedesignof piezoelectric
transducers,
in
a sandwichconfigurationusinga steppedhornasparticlevelocityamplifier. The ca3ndition
for maximumpowerdeliveryto the load impedanceis
establishedin terms of the parametersof the horn and the piezoelectric
material• Analytical solutionscan be found readily if one of the horn
lengthsischosen.If thisisdone,thentherearetwo arearatiosthat satisfy
the maximumpowercondition.The methodof falsepositionthat is suitablefor findingsolutionsnumericallyin a generalcaseby usinga comput-
RR4. Developmentof sphericaland cylindrical polarization for threedimensionalpiezoelectricfinite elements.P. Tietee,'• K. Anifrani,'• J.
er is aisc described.
Fours Lea Plagcs,France)
$95
d. Acoust.Sec. Am.Suppl.1, Vol.82, Fall 1987
2:20
C. Debus,J.C. Decarpigny(InstitutSup6rieurd'ElcctroniqueduNord,
41 Bd Vauban,59046 Lille Cedex,France), and D. Boucher(Groupe
d'Etude et de Recherchecn Detection SousMarine, Le Brusc, 83140 Six
114thMeeting:AcousticalSocietyof America
$95
Three-dimensional
analysisof sphericalor cylindricaltransducers
with axiallyor radiallypolarizedpiezoelectric
ceramicsis ratherdifficult
because
it needsa largenumberof classical
elementsto takeintoaccount
the correctpolarization.A new type of piezoelectricfinite elementhas
beendevelopedin the ATILA code [J. N. Decarpignyet al., J. Acoust.
Soc.Am. 78, 1499( 1985) ] to obtaina goodrepresentation
of the polarization.This paperdescribes
theseelementsand analyzesthe results(in
air resonance
modes,electricalcharacteristics,
and modeshapes)ob-
of flow and soundsources.L. M. B.C. Campos(InstitutoSuperior
tainedon someexamples.
a) Currentlyat SINAPTEC, 41 Bd Vauban,
T6cnico,1096LisbonCodex,Portugal)
atedby thesourceagainstthecharacteristic
impedance
andtheotherby
reflectingthe rearwardwave (incidenton the source)off the sourceimpedance.This principleis seminalin linkingthe two approaches.
3:20
RR8. On the natureof acousticsingularitiesarisingfrom the coincidence
59000 Lille, France.
2:35
RRS.Useof special
waveforms
foroptimum
efficiency
ofhigh-intensity
soundsources.
FredericG. Pla (SverdrupTechnology,
Inc., NASA
LcRCGroup,16530Commerce
Court,P.O. Box30650,Midpark
Branch,MiddleburgHeights,OH 44130)andGerhardReethof(Noise
ControlLaboratory,157 HammondBuilding,UniversityPark, PA
16802)
High-intensitysoundsources,
suchassirens,havereceivedmuchat-
tention
intherecent
pastduetorenewed
interest
inindustrial
applications
of high-intensity
acoustics.
Asa resultof theveryhighsound
pressure
levelsrequired( 155-165dB), finiteamplitudeeffectsmustbetakeninto
accountin thedesignof soundgenerators.
A timedomainsolutionof the
second-order
nonlinear
waveequation
isusedto predictthebehavior
of
initiallynonsinusoidal
planewaves,
andiscompared
witha frequencydomainapproach.
Results
for initiallysinusoidal,
rectangular,
andin-
Thecoincidence
thatflowandacoustic
sources
canoccurin important
acoustic
problems,
e.g.,a spherical
wavein a conicalductcontaining
an
incompressible
meanflow,isan exampleof flowandsoundsources
colocatedat thevertexof thecone;theconeistheparticularcasen = 1 of the
power-lawductsof cross-sectional
areaS(x ) • x 2" whichexhibit,for all
real n, coincidenceof flow and sound sourcesor sinksat x = 0 or x =
It isshownthat thecoincidence
of flow andsoundsourcescanlead,for the
powerlaw ducts,to algebraicsingularitiesfor the phase,and essential
singularities
fortheacoustic
field;a transformation
involving
thesolution
of a particularRicattiequation
isusedto accountfor theessential
singularity, and regularizethe acousticproblem.Exactsolutionsare obtained
for soundin parabolicandhyperbolic
nozzles,andtheseareusedto study
theacousticfieldin theray,asymptotic
andcompactness
approximations,
compareacoustic
velocityandpressure,
discuss
equipartition
andbiasing
of kineticand compression
energies,
and conservation
and nonconserva-
tion of waveaction.The dualityprinciplefor horns[R. W. Pyle, J.
Acoust.Soc.Am.37, 1187A (1965)] isshownto fail,andhavenosimple
extension,for nozzles.
verse-shock
wavesare presented.
It is shownthat the shockformation
distancefor an initiallyinverseshockwaveis•r timestheshockformation
distancefor an initially sinusoidalwave, and that the wave distortion
actually
results
inanamplification
ofthefundamental,
thusincreasing
the
efficiency
of thesoundgeneration
process.
The consequences
of wave
distortionon severalpracticalhigh-intensity
soundsources
is discussed.
3:35
RR9.Whispering
galleryresonances
onsolidelasticspheroids.
A. Nagl
(Departmentof Physics,CatholicUniversity,Washington,
DC 20064),
M.F. Wcrby (NavalOceanR&DActivity, Code221,NSTLStation,MS
39529),H. Oberall(DavidW. TaylorNavalShipR&D Center,
2:50
RR6. The distortionspectrumof the fractionallyaddressed
digital
oscillator.
W. M. Hartmann(Physics
Department,
MichiganState
University,E. Lansing,MI 48824)
Thetechnique
offractional
addressing
permits
onetoconstruct
adigital oscillator
with arbitrarilyhighfrequency
resolution.
However,the
technique
introduces
distortion.
Thedistortion
powerspectrum
maybe
calculated
exactly
byborrowing
mathematical
methods
fromcrystallography,suchthatthecrystallographic
unitcelllengthequals
thedenomi-
Annapolis,MD 21402andDepartmentof Physics,CatholicUniversity,
Washington,DC 20064), and J. W. Dickey (David W. Taylor Naval
ShipR&D Center,Annapolis,MD 21402)
UsingtbeNORDA T matrixcode,backscattering
amplitudes
versus
frequency
havebeencalculated
fortheaxialincidence
ofa planeacoustic
wavein wateronsolidtungsten
carbide
spheroids
witha largevarietyof
aspectratios.Besides
theusualseriesof broadRayleighwaveresonances,
seriesof narrowwhispering
galleryresonances
areobserved
andinvestigated.The dominantmodenumberof eachof theseresonances
is identi-
fiedbyaninterpretation
of thebistatic
scattering
pattern.Forincreasing
natorof theirreduciblefractionalpartof theaddress
increment.The calculationexhibitsremarkablemathematicalsymmetries,
whichlead to
aspectratios,it is notedthat an increasing
numberof the lowest-order
whispering
galleryresonances
failtobeexcited.A possible
explanation
of
simpleclosed-form
expressions
for thelevelsof thecomponents
in the
distortion
spectrum
andforthetotalrmsdistortion.
Theexpressions
show
howthedistortion
maybeminimized
orpossibly
employed
asanalternativetodigitalFM inthesynthesis
ofcomplex
tones.[Worksupported
by
thisphenomenon
isdiscussed,
based
onphase
matching
arguments
forthe
circumferential
propagationof surfacewaves.
3:50
the NIH. ]
3:05
RR7. Analyticalmodelingof an activenoisecontrolsystemin a duet.M.
L. MunjalandL. J. Eriksson(CorporateResearchDepartment,Nelson
Industries,Inc., P. O. Box 600, Stoughton,WI 53589)
Makinguseof the transfermatricesandelectroacoustic
analogies,
a
standingwave analysisof the activenoisecontrolsystemin a duct is
presented
incorporatingthecharacteristics
of the primarysource,aswell
astheauxiliarysource.Analyticalexpressions
havethusbeenderivedfor
the ratioof the twosourcepressures
andcertainotherratiosor relationsof
interestfor completecancellation
of noisedownstream
of the auxiliary
source.Theseexpressions
are then comparedwith thoseobtainedfrom
transferfunctions
of thevariousblocksconstituting
theblockdiagramof
the entire system.In the process,equivalencehas been established
betweenthe differententitiesinvolvedin the two approaches,
one of
whichisusedin acoustics
andtheotherin systemtheory.In particular,it
hasbeenshownthat the pressure
generated
by a sourceagainsta load
impedance
canbelookeduponasa sumof two pressure
waves,onegener-
S96
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall 1987
RR10. Soundradiation from beamsunder the action of movingline
forces. R. F. Keltie and H. Peng (Department of Mechanical and
AerospaceEngineering,North CarolinaStateUniversity,Raleigh,NC
27695-7910)
The topicof soundradiationfrom beamsunder the actionof harmonic
line forcesmovingat subsonicspeeds(M < 1) is studied.The nondimensionalsoundpowerexpressions
are obtainedthroughthe integrationof
the surfaceintensitydistributionover the entire beam.An asymptotic
expression
for the soundpowerin the low-frequency
regionis derived
dependingupon the characteristics
of the fluid loadingand the spatial
extentof the appliedforces.Numericalintegrations
havebeenperformed
to determinetheeffectsonthe radiatedsoundpowerof theMach number
M, theacoustic
lengthoflineforceKoL,andthewavenumber
ratioy. The
resultsshowthat: For beamsunderheavyfluid loading,the effectof the
speedof themovingforceisnotpronounced;
whilefor beamsunderlight
fluidloading,the uniquecoincidence
radiationpeakat ?'• 1 for a stationary force (M = 0) is split into two coincidencepeaks(locatedin the
frequencyregion?'< 1 and ?'> 1, respectively)due to the effectsof the
Dopplershift.The valuesofKoL that suppress
the coincidence
peaksare
alsochangeddue to the motionof the line force.
114thMeeting:Acoustical
Societyof America
S96
THURSDAY
AFTERNOON,
19 NOVEMBER
1987
TUTTLE SOUTH ROOM, 1:30 TO 5:00 P.M.
SessionSS. Noise V and Bioresponseto Vibration II: Effects of Man-Made Noise on Animals and Animal
Communication
William C. Cummings,Chairman
Oceanographic
Consultants,5948 Eton Court, San Diego, California 92122
Chairman's
Introduction--l:30
Invited Papers
1:35
SS1. Reviewof studieson the effectsof man-inducednoiseon marinemammalsof the Bering,Chukchi,and
Beaufort Seasand how the resultshavebeenappliedto federal offshoreoil and gasmanagementdecisions.
JcrryL.ImmandClevclandJ.
Cowles
(MincralsManagcmentService,
Alaska
OCSRegion,
Anchorage,
AK
99508-4302)
The U.S. MineralsManagementServicehasbeenfundingandmanagingstudiesof the potentialeffectsof
man-inducednoiseon marinemammals,particularlyendangeredcetaceans,in the Bering,Chukchi,and
BeaufortSeassince1978,and hasexpendedapproximately$5,000,000towardthoseefforts.The purposeof
suchstudiesis to provideinformationneededfor informeddecisionmakingpertainingto environmentally
soundleasingand management
of offshoreoil and gasdevelopment
on the AlaskaOCS. Many of the noise/
marine mammalinteractionstudieshavebeenusedto establishor modify leaseterms or regulationsfor
offshoreoperations
in federalleaseareas.Also,theseresultshavebeenimportantin resolutionof litigation
pertainingto OCSoil andgasleasing/exploration.
Specificcaseexamples
of howresultshavebeenappliedwill
be presented
andprojectionof futureAlaskainformationneedsin thisdisciplinewill be discussed.
2:00
SS2. Potential impacton seaturtles, dolphins,and fishesof explosivesusedin offshoreplatform removals.
Edward F. Klima, Gregg R. Gitschlag, Maurice L. Renaud (National Marine Fisheries Service, 4700
AvenueU, Galveston,
TX 77551-5997),andWilliamC. Cummings(Oceanographic
Consultants,
5948Eton
Court, SanDiego, CA 92122)
A highincidence
of strandings
of seaturtles,bottlenose
dolphins,andfisheswasrecorded
onthebeaches
in
thenorthwestern
Gulf of MexicoduringMarch-June1986,whenexplosives
wereusedto removeseveral
oil
platformsin adjacentoffshorewaters.Prior to, during,and after March-Juneof the followingyear, 1987,
strandings
for thesameareaweresignificantly
lower,or negligible.
Recoverylocations
of driftbottlesreleased
at the siteof theexplosions
werecorrelatedwith someof the strandings.
Wild turtlesandbottlenose
dolphins
wereobserved
in thevicinityof theplatformsduringremovaloperations.
Abnormal(stunted)Kemp'sridley
andloggerhead
seaturtleswereplacedat variousdistances
fromplatformsandexposed
toexplosions.
Preliminaryresultsfromexposure
studies,includingthedeathof a Kemp'sridley50 yardsfrom theexplosionandan
unconscious
loggerhead
turtle approximately1000yardsfrom the explosion,are described.
Allowingfor inbottomloss,receivedsound-pressure
levelswerecalculatedto be 235 dB (50 yards)and greaterthan200 dB
wherea cagedloggerheadwasfound unconscious.
2:25
SS3. A review of noise effects studiesfrom the U.S. west coast. Dilworth W. Chamberlain (ARCO,
Environmental
Protection,515SouthFlowerStreet,LosAngeles,CA 90071)
Concernoverthepossibility
of effects
fromgeophysical
activityonmarineorganisms
hasrecentlygeneratedseveralresearch
studies
in California.Resultsof effectsstudies
by compressed
air releases
fromairguns
(seismic
energyreleases)
onfishdispersion
anduponphysicaleffects
to fishhavebeenobtained.
Thisinformation includesthe physicaleffectsof a simulated,towedgeoseismic
array on northernanchovy(Engraulis
mordax)eggs,larvae,andadults.Otherstudieshaveproduceddataabouttheschooling
behaviorof rockfish
(Sebastes
spp.) exposed
to airgunreleases.
Additionalresearch
addressing
theeffects
ofseismic
energyreleases
on Dungcncssc
crab (Cancermagister)eggsand larvaeandon rockfishbehaviorarebeingplannedfor the
watersof Californiaand Washington.
2:50
S$4. The influence of sound propagation conditions on the behavioral responseof whales to underwater
industrial noise. Charles I. Maline and Paul R. Miles (Bolt Beranek and Newman Laboratories, Inc., 10
MoultonStreet,Cambridge,MA 02238)
Resultsof recentstudiesinvolvinggray, humpback,and bowheadwhalesshowthat whalestendto avoid
areaswith highunderwaternoiselevels.Data obtainedfromwhalebehavioralobservations
duringcontrolled
S97
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
114thMeeting:Acoustical
Societyof America
$97
exposure
to representative
industrial
noisesources
permitdetermination
oftheprobability
ofavoidance
Paof
thesourceregionasa functionof thenoiselevelL,. The zoneof influenceof a sourcemaybedefinedasthe
regionwherePa> 0.5.WhiletheL, requiredto produce
thisdegree
ofavoidance
hasbeenfoundto dependon
whalespecies
andsourcetype,somegeneralizations
maybemade.For low-frequency
continuous
noise,50% of
thewhalesexposed
havebeenobserved
to avoidregionswheretheoverallL, ishigherthan 115to 125dB (re: 1
pPa). Soundtransmission
conditions
at a specific
sitedetermine
thedistance
fromthesource,whereL, falls
belowthePa = 0.5 criterionlevel.Thezoneof influence
thushasbeenfoundto varyconsiderably
for thetest
sitesinvestigated.
For example,a drillshipoperatingat a test site off the AlaskanBeaufortcoasthasan
estimatedzoneof influenceradiusof 4 km, but, off the coastof California,the estimatedzoneof infiuenee
radiusisreduced
to I km. [Work sponsored
by theMineralsManagement
Service.
]
3:15
SS5. Reactionsof bowheadwhalesto drilling and dredgingnoise in the CanadianBeaufort Sea. W.
JohnRichardson
(LGL Ltd., Environmental
Research
Associates,
P.O. Box280,King City, OntarioLOG
IK0, Canada),BcrndWfirsig(MossLandingMarine Laboratories,
P.O. Box 223, MossLanding,CA
95039), and CharlesR. Greene,Jr. (GreeneridgeSciences,Inc., 5276 Hollister Avenue,Suite408, Santa
Barbara, CA 93111 )
Behavioral
reactions
ofbowhead
whales,
Balaenamysticetus,
toseven30-to40-rainunderwater
playbacks
ofrecorded
drillship
anddredge
noiseweredetermined
in 1982-1984.
Waterdepthswere10.-150
m withlittle
or noice.Some(butnotall) bowheads
oriented
awaywhenreceived
noiselevelsandspectra
resembled
those
several
kilometers
fromactualdrillships
anddredges.
Duringsomeplayback
tests,
callratesdecreased,
feeding
ceased,andcyclesof surfacing,respiration,anddivingchanged.Sensitivityof variouswhalesto noisediffered.
Roughly
halfresponded
toreceived
noise
levels
ofabout115dBre:I pPabroadband,
orabout110dBinone«octband(20-30 dBaboveambient).Suchlevelsoccurred3-11 km froma drillshipanddredgein theCanadian
BeaufortSea.Bowheads
occasionally
wcrcseenlessthan5 km fromactualdrillships
anddredges,
where
received
noiselevelswereat leastashighasduringbriefplaybacks.
Thussomebowheads
mayhabituateto
prolongednoiseexposure.
Alternatively,onlythe least-sensitive
individualsmayoccurlessthan5 km from
drillships
anddredges.
[Work supported
by U.S.MineralsManagement
Service.]
3:40-3:45
Break
ContributedPapers
3:45
SS6.Effectsofnoiseofa proposed
oceanthermalenergyconversion
plant
4:00
SS7. Drill-site sounds and bowhead whale calls. Charles R. Greene
on marine animals--A preliminary estimate.Robert S. Gales and Suc
(GreeneridgeSciences,Inc., 5276 Hollister Avenue,Suite 408, Santa
E. Moore (SEACO, Inc., 2845-D Nimitz Boulevard,SanDiego,CA
Barbara, CA 93111 )
92106), William A. Friedl (Naval Ocean SystemsCenter, Kailua,
Hawaii 96734), and JamesRucker (National Oceanographic
and
Atmospheric
Administration,
Washington,
DC 20235)
An analysisis presentedof the predictedunderwaternoisefrom a
proposed
40-MW oceanthermalenergyconversion
(OTEC) plantto be
located
approximately
• mileoffshore
ofKahcPoint,Oahu,Hawaii,and
itspotentialeffects
onthemarineanimalsof thearea.The requiredtotal
warm and cold seawaterflow of approximately1.6 million liters/rain
involves
16pumpsdrivenbya totalof 17000horsepower.
Earlierstudies
[C P. Janotaand D. E. Thompson,J. Acoust.Soc.Am. 74, 256-266
(1983)] calculatedthe noisegenerated
by variousproposed
OTEC systems,and comparedit with actual measurements
on a I-MW research
system(OTEC-1) operatingoff Hawaii. Theseanalyticprocedures
are
utilizedto predictthenoisefor the40-MW plant.Underwater
noisegeneratedduringtheconstruction
phaseisexpected
to exceed
theplantnoise,
butfora relativelyshortperiod.Generalauditoryperception
andexpectedresponses
ofcetaceans
andfishes
oftheareatobothplantoperation
and
construction
noisesarediscussed.
The mostlikelybehavioral
responses
includetemporarydisplacement
fromthe areaof the plantandpartial
maskingof communicative
signals.[Work supported
by NOAA.]
S98
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
Bowheadwhales,an endangered
species,migratewestwardalong
Alaska'snorth coastduring Septemberto October,when ice conditions
are bestfor oil explorationson the outercontinentalshelf.Concernexists
that marineactivitysoundsmay adverselyinfluencewhalebehavior.Un-
derwatersoundsweremeasuredin the fall of 1986near two drillship
operations20 and 35 km offshore,northwestof Kaktovik, Alaska,with
waterdepthsof 34-35 m. Soundlevelsat range0.2 km, 20-1000 Hz, for
threesupportshipsunderwayat 10-12 kn (standardspeed)were 130,
137, and 145 dB re: I 3tPa.The level from the strongestice-breaking
source,
samefrequency
bandandrange,was148dB.Corresponding
levels
from the drillshipwere 135-136dB duringdrillingand cleaningand 130
dB during tripping.For measurements
within 0.4 km, soundlevelswere
highestin «-octbandsfrom50-100Hz. Hourlymeasurements
for 20 days
at 11 km from one site revealed a median level of 114 dB in the 20-1000-
Hz band,with 5thand95thpercentilelevelsof 108and 125dB,respectively. Dominantsounds
at thatdistance
camefromthedrillshipandsupport
ships.Continuousmonitoring during 20 days recorded206 bowhead
calls,with 29 of themlocated9.5-24 km from the drillship.[Work supportedby ShellWesternE&P, Inc.]
114thMeeting:Acoustical
Societyof America
S98
4:15
perorgeese
wasinitiatedontheAlaskaPeninsula
andontheNorth Slope
$$8. Usi[ng
sounds
tocontrolthemovements
ofsesotters.R, W. Davis,
F. W. Awbrey,andT. M. Williams(SeaWorldResearch
Institute,
Hubbs
MarineResearch
Center,
1700South
Shores
Road,SanDiego,
CA
ofAlaska.
Theobjectives
wereto:( l ) describe
thebehavioral
responses
of
geeseasan effectof noisefromaircraftoverflights;(2) recordandexam•
incnoiseassociated
withexperimental
overflights
of fixed-androtary-
92109)
wingaircraftandspecific
altitudes,airspeeds,
andenvironmental
condi-
Fieldtestswereconducted
in PrinceWilliamSound,Alaska,to determinewhethertheplaybackof artificialsounds,killer whalecalls,or sea
otterpupcallscouldbeusedto controlthemovements
of seaotters(En-
tions; (3) securebaselinenoise levels for routine flights of
nonexperimental
aircraft;and (4) providerecommendations
to governmentagencies
forreduction
ormitigation
ofanyadverse
impacts
associatedwithaircraftnoisetothesepopulations
ofgeese.
Behavior
ofgeese
was
monitored
fromremotelocations
priorto, during,andfollowinglevel
hydralutris).Testswereconducted
on threegroups
of fiveadultotters
thatwerecaptured
andplaced
in anenclosed
lagoon( 180m longX 40m
wide).Sounds
werebroadcast
in air andunderwater
froma platformin
thecenterof thelagoon.The behavioranddistanceof theottersfrom the
platformweredetermined
fromvideorecordings
obtainedfroma remote-
overflights
alongprescribed
routes.
Concurrently,
«-octsound
exposure
and maximumA-weightedand soundlevelsof eachaircraft weremeasuredwith a realtimeanalyzer.Here,thedesignandpreliminaryresults
of the firstof a multiyearstudywill bediscussed.
controllext
videocameraoverlooking
thelagoon.Theresults
showed
that
seaotterswerenot repelledby loud (SPL = 120dB at 1 m), obnoxious
soundsin air suchasa warblelone (frequency-modulated
sinusoidcen-
teredat ItkHz) orair hornsandnarrow-band
pulses
at frequencies
orS00
Hz-20 kHz projectedunderwater.However,the otterswereattractedto
theaerialplaybackof seaotterpupcallsandrepelledby the aerialand
underwater
playback
of killerwhalecalls.Psyehoacoustic
stimuliappear
to havethebestchanceof influencing
themovements
of wildseaotters.
[Thisresearch
wassupported
by MineralsManagement
Service,
Contract No. 14-12-0001-30256.]
4:45
SS10. Acousticcommunication
in P. Tigris.Harry Hollien (IASCP,
Universityof Florida, Gainesville,FL 32611)
Whilenootherspecies
exhibitstheextensive
language
systems
of humans,a numberare seento passinformationby oneor morebehaviors.
Prominentamongthe observedsignalsare thoseof an acousticnature;
4:30
SS9. Effectsof aircraftnoiseon Pacificblackbrantandothergeesein
Alaaka. David H. Ward, Dirk V. Derksen (U.S. Fish and Wildlife
Service,1011 East Tudor Road, Anchorage,AK 99503), and Paul
D. Schomer (U.S. Army ConstructionEngineeringResearch
Laboratory,P. O. Box4005,Champaign,
IL 61820)
In 1987,a studyof the effectsof aircraft noiseon the behavior,distri-
bution,zaadhabitatuseof Pacificblackbrant,Canadiangeese,andera-
indeed,
somesubspecies
ofbirdsdemonstrate
fairlycomplex
communicativenetworks.
AmongthePanthera,
P. Tigrisisperhaps
themostvocal.
ExtensiveS/R experimentation
with sevencaptivetigersandsubjective
observation
of nineothers(plusevaluationof a fewcallsrecordedin the
field), haveresultedin classification
of ten meaningful
utterances
plus
two othersthat maybe informationbeating(not yet "decoded").This
systemappearsto be somewhatmorecomplexthan that exhibitedby
Tursiops
T. (and certainlymoresothanthatof thecommondolphin).
Thesecond
stageof thisprojectinvolves
playbackofrecorded
andsynthesizedcalls in order to confirm (or not) the behaviorsnoted.
THURSDAY AFTERNOON, 19 NOVEMBER 1987
TUTTLE NORTH ROOM, 1:30TO 5:00 P.M.
SessionTT. Structural Acoustics and Vibration V: Viscoelastic Materials: Their Characterization and
Application
Fred Sehloss,Chairman
Wilcoxen
Research,
2096 GaitherRoad,Rockville,Maryland20850
Chairman's Introduction--l:30
1:35-2:00
TT1. PanelDiscussion:
Characterization
of Viscoelastic
Polymers
Wayne T. Reader, Moderator
PANEL
MEMBERS:
B. L. Burkewitz
R. J. Capps
B. Hartmann
R. F. Landel
L. Rogers
D. J. Townend
R. J. Wetton
S99
d. Acoust.Soc. Am. Suppl.1, Vol. 82, Fall 1987
114th Meeting:AcousticalSocietyof America
ContributedPapers
2:00
TT2. Structure and acousticalpropertiesof PTMEG polynrethanes.
Corley M. Thompson (Underwater Sound ReferenceDetachment,
occurin practice,the theorydoesnot permit mastercurvesto be constructedby theusualWLF frequency
shiftmethod.Implicationsof this
fact for dealingwith experimentalbulk modulusdata are discussed.
Naval ResearchLaboratory,P.O. Box568337,Orlando,FL 32856-8337)
and Karen L. Gebert (PCR, Inc., P.O. Box 1466, Gainesville, FL
2:45
328602)
Polyurethanesare widely usedin underwateracousticaldevicesbecauseof their convenience
and attractivephysicalproperties.Rarely,
however,havethesepolyurethanes
beendesigned
for thespecificapplication. More typically,a commercialmaterialis usedin both sound-transmissionand sound-absorption
applications,usuallywith little under-
standingof structuralparameters
thatcontrolthe acoustical
properties.
Thispaperwill showthattheacoustical
properties
ofthesepolynrethanes
maybemodifiedby changing
thesizeof thePTMEG softblock,
andthat
adjustment
of thesoftblock
components
is ineffective
in producing
such
changes.
Evidencewill bepresented
that thestructuralmechanism
for the
correlationbetweenacousticalpropertiesand softblocksize is the decreasingsolubilityof the hardblockmaterialwith increasing
softblock
molecularweight.Thisdecreased
solubilityresultsin a morepuresoftblockandin lowerdynamiclosses
andlowerspecific
acoustic
impedance.
The evidence
for thisistheregularchangein thesoftblock's
glasstransition temperaturewith molecularweight.The acousticalramifications
of
theserelationships
will be discussed.
TTS. An algorithmfor applyingtheWilliams,Landel,andFerrymethod
of reducedvariables.
JamesJ. Dlubac,RichardJ. Deigan,andWayne
T. Reader (Code 1905.2,Ship AcousticsDepartment,David Taylor
Naval ShipR & D Center,Bethesda,MD 20084-5000)
The measurement
of the dynamiccomplexmodulusof viscoelastic
materials
onanyapparatus
is confined
to a limitedfrequency
andtemperaturerange.Williams,Landel,andFerry(WLF) [J. D. Ferry,g'iscoelastic
Properties
ofPolymers
( Wiley,NewYork,1980), 3rded.Chap.11]
reasoned
thatan increase
in temperature
produces
an identicaleffectin a
viseuelastie
materialasa decrease
infrequency
andviceversa.Empirically, then,thereis a correspondence
between
temperature
andfrequency.
The WLF methodof reducedvariableswasproposed
as a methodof
extending
theeffective
frequency
rangeof thedynamicmodulusandloss
factor.Thistechnique
involves
measuring
thecomplex
modulus
overa
limitedfrequency
rangeanda varietyof temperatures.
Thedataat differenttemperatures
arethenplottedversus
frequency
andshifted
alongthe
frequencyaxisuntil a smoothcurveresults.The effectsareshiftedmodu-
luscurves
describing
thecomplex
modulus
overa broadfrequency
range
2:15
Tr3. Relationship between italyurethane compositionand viscoelastic
propertiesof model urethanesystems.R. N. Capps, G. M. Stack, E.
M. Dodd (Underwater Sound Reference Detachment, Naval Research
Laboratory, P.O. Box 568337, Orlando, FL 32856-8337), and E.
Y. Chang (American Cyanamid,Bridgewater,NJ 08807)
A studywasperformedto determinethe relationshipbetweenpolyurethanecompositionand viscoelastic
propertiesin a seriesof model
urethanecompounds.The compositionalvariablesstudiedincludedthe
natureof the softsegment,amountof hard segment,and cure stochioroetry.Model urethanes
werepreparedusingthealiphaticdiisocyanate,
metatetramethyleue
diisocyanate(m-TMXDI). This aliphaticisocyanateis lessreactivethancommonlyusedaromaticisocyanates
anddoesnot
undergothesecondary
crom-linking
reactions
commonlyobserved
with
aromaticisocyanates.
The urethaneschosenfor thisstudycontainedsoft
segments
basedon hydroxy-terminated
polybotadiene
(HTPBD) or polycaprolactone
(PCL), whichis a highlypolar materialin whichextensive phasemixing shouldoccur. In contrast,polyurcthanes
basedon
HTPBD shouldundergomorecompletephaseseparation.
Prcpolymers
werepreparedwith both of thesesoftsegmentsand with availableisocyanatecontentsvarying from 3.7% to 5.7%. Diethyltoluenedismine
{DETDA) wasusedto cure theseprepolymersover a rangeof cure stochiometries.Therma]transitionsattributedto the hard and softsegments
wereobserved
in theseurethanes
usinga Perkin-ElmerDSC-4. Dynamic
meehancial
behaviorwasmeasured
usingbotha PolymerLabsdynamic
mechanical
thermalanalyzer(DMTA) anda resonance
apparatus
developedat theNRL-USRD. [Sponsored
by ONT.]
2:30
at somefixedtemperature.
Typically,theWLF shiftrequires
several
runs
at temperatures
closeenough
sothatthemodulus
ofonerunoverlaps
the
next.In thispaper,theWLF methodof reducedvariables
isreviewedand
analgorithm
foraccomplishing
theWLF shiftisinvestigated.
Thisalgorithmshiftsdynamicmodulus
dataat varioustemperatures,
theconsecutiverunsof whichmaynotcontainoverlapping
toodull.
3:00
TY6. Effects of aging on dynamic bulk moduli of several elastomers.
J. Burns (Florida Instituteof Technology,Melbourne,FL 32901), P.
S. Dubbelday, and R. Y. Ting (Underwater Sound Reference
Detachment, Naval ResearchLaboratory, P. O. BOx 568337, Orlando,
FL 32856-8337)
Samples
of naturalrubber,butylrubber,neoprene,
andpolyurethane
wereagedfor a total of 24 monthsat roomtemperaturein seawater.The
dynamicbulk moduluswasmeasuredfor eachsampleat intervalsduring
the2-yr agingperiod.Age-induced
changes
in thedynamicbulk moduli
wererelativelysmallin all cases,
butthereweredistinctdifferences
among
the varioustypesof elastomerstested.In general,agingeffectsappear
considerably
more pronouncedfor shearand Young'stoodullthan for
bulk toodull. Possible reasons for this are discussed.
3:15
TY7. An automatedsystemfor characterizingthe vl'brationdamping
propertiesof mater'als.M. L. Drake (Universityof Dayton research
Institute,300 CollegePark, Dayton,OH 45469), R. G. Smiley(Entek
Scientific Corporation, Cincinnati, OH), and D. M. Hopkins
( Universityof Dayton ResearchInstitute,300 CollegePark, Dayton, OH
45469)
•F4. Bulk modulusthermoviseoelastieitytheory for rubberyelastomers.
J. Burns(Florida Instituteof Technology,Melbourne,FL 32903) and P.
S. Duõbelday (Underwater Sound Reference Detachment, Naval
ResearchLaboratory,P.O. BOx568337,Orlando,FL 32856-8337)
Earlierattemptsto developa free-volumetheoryof thedynamicbulk
modulus
ofrubberyelustomers
[J. Burnseta!.,J.Aeoust.Soc.Am. Suppl.
I 79, S62 (1986) ] led to separateexpressions
for the frequencydependenceof the modulusat constanttemperatureand for the temperature
dependence
atconstantfrequency.
Thesehavenowbeencombined
togive
a free-volume-based
theoryfor the bulk modulusas a functionof both
frequencyand temperature.For certainrangesof parameters
that may
S100
J. Acoust.Soc.Am.Suppl.1, VoL82, Fall1987
In 1980 ASTM finalizedthe dampingcharacterizationstandardE756-80 around the resonantbeam test method (M. L. Drake and G. E.
Terborg, TechnicalReport AFWAL-TR-80-4093, 15 January 1976-31
December1979). The Universityof Dayton, in conjunctionwith Entek
Scientific,developeda computer-aided
testsystemthat automatedthe test
procedures
and data reductionequationprescribedin E-756. This softwarepackage,combinedwith theappropriatehardwaresystem,resultsin
an efficientworkstation
for conducting
dampingcharacterization
studies
of materials
anddesigning
effective
dampingsystems
utilizingthedampingproperties
determined.
The presentation
will outlinethe philosophy
and operationof the system,includingdiscussions
on the systemauton-
114thMeeting:
Acoustical
Societyof America
S100
omyandthefunction
ofeachsystem
component;
atypicaltestsetup,
data
reduction,
andhomogram
generation;
andanexample
of a damping
designdevelopment.
example,thesystemmaybeusedto investigate
thedynamicproperties
of
viscoelastic
polymerscontainingfinite sizedinclusionssuchas chopped
fibersor plateletfillers.Exampleswill be presentedof the system'suseto
examine
thereinforcement
provided
byglassfibersofseveral
lengths
ran3:30
domlydispersed
throughouta viscoelastic
polymer.
TYS. Dynamic material property measurements
using the Polymer
Laboraturies'
dynamic
mechanical
thermalanalyzer.RichardJ. Dcigan,
WayneT. Reader,and JamesJ. Dlubac (Code 1905.2,ShipAcoustics
Department,David Taylor Naval Ship R & D Center, Bethesda,MD
20084-5000)
Thebasicprincipleof measurement
of anydynamicmechanical
property apparatusis to infer the elasticand lossmodulifrom the measured
responseof a sampleand a known theoreticalsolution.The extentto
whichthemeasured
response
ismodeledby thetheoreticalsolutiondeter-
minesthevalidityof theinferredmaterialproperties.
Thepurpose
of this
paperis to investigate
the measurement
of the dynamictoodullof viseoelosticmaterialsusingthedynamicmechanical
thermalanalyzermanufactured by Polymer Laboratories,Inc. The complexYoung's modulus
[E * = E'( 1 + i•/E) ] or shearmodulus[G * = G' ( 1 + i•la ) ] is determinedat frequencies
rangingfrom0.01to200Hz at temperatures
ranging
from -- 150'C to 300'C. The Young'smodulusis foundthroughthe
bendingof eithera doubleor singlecantileverbeam.The WLF shiftis
employedon data at severaldifferenttemperatures
to generateshifted
modulus
curvesofE' and•/Eand/orG' and•/a versus
extended
frequency
for fixedtemperature.
Computer-generated
shiftedmoduluscurvesofviscodastic materials are discussed.
3:45
'Fr9. Viscoelastic
constants
for pressurereleasematerials.Gary Caille,
Jacek Jarzynski,Peter Rogers,and GeorgeW. Woodruff (Schoolof
MechanicalEngineering,GeorgiaInstituteof Technology,Atlanta, GA
4:15
TTll. Constrainedviscoelasticlayer asusedto dampenstructuresunder
multiplestrainingmodes.M. Bonnetand B. Garnier (Metravib R.D.S.,
64 ChemindesMouilles,69130Ecully,France)
The designof viscoelastic
dampingmechanisms
requiresbotha thoroughknowledgeof the viscoelastic
propertiesof materialsand proper
dimensioning
andtoolscapableof handlingall cases.This is particularly
importantwhendealingwithaerospace
structures
wheretheweight-toperformance
ratioiscritical.Thispointis illustrated
usinga specific
example.Here,analuminumhoneycomb/carbon
skinsandwich
isdamped
to handleexplosion
shockwavesovera frequency
bandwidthof 1 to 10
kHz at a temperature
of -- 20 øC.Dynamicmechanical
analysis(in modulusand lossangle) on a varietyof materialsled to the selectionof an
appropriatepolyurethaneelastomer.The resultingsandwichstructure
accounts
not only for bendingmodes(usingRuzicka'stheory),but for
tensioncompression
andshearmodesaswell (inspiredfromY.V.K. SadasivaRaoandB.C. Nakra). Thiscompromise
is obtainedthroughthe
development
of specificsoftware,whichisbothsimplerandquickerthan
a finiteelementanalysis.A goodagreement
betweentheoryandexperimentat roomtemperature
isshown.Thewaterfallvisualization
technique
usedisparticularlyusefulin detailingapparentmechanisms
forall configurations:
bending,shearing,
andtensioncompression.
Theseresultsareso
encouraging
that furtherdevelopment
of thistechniqueisjustified.
30332)
4:30
A comparison
of experimentally
andtheoreticallydeterminedviscoelasticconstants
for closedcellneoprene
rubberandcorpreneispresented.
Both of thesematerialshaveair concentrations
of greaterthan 50% by
volumeand exhibitlargeacousticattenuation.The longitudinalsound
speedis approximately150m/s for the closedcell neoprenerubberand
340m/s for thecorprene.The experimental
constants
determinedarethe
complexYoung'smodulusand complexplane-wavemodulusin the frequencyrangeof 500 to 5000Hz. Standardexperimental
techniques
for
measurement
ofthesetoodullareused.The experimental
dataarecorrected for multipleinternalreflections
by useof thecomplexcepstrumsignal
processing
technique.
The theoreticalpredictions
are basedon multiple
scattering
modelsandquasistatic
meanelasticfieldmodels.[ Work supported,in part, by ONR Code 1125A.]
4:00
TYI0.
Dynamic shear modulus measurements of fiber reinforced
Imlymersusingforcedtorsionalvibrations.WayneT. Reader,James
J. Dlubac, and Richard J. Deigan (Code 1905.2, Ship Acoustics
Department,David Taylor Naval Ship R & D Center,Bethesda,MD
20084)
TT12. Measurementof complexelectromechanicalpro•rties of highly
damped piezoelectric materials. F. DouglassShields (Physics
Department,Universityof Mississippi,University,MS 38677) and Kurt
M. Rittenmyer (Underwater Sound ReferenceDetachment, P.O. Box
568337, Orlando, FL 32856-8337)
The mechanicalresonance
techniquefor determiningthe dielectric,
elastic,and electromechanical
propertiesof piezoelectricmaterialshas
beendevelopedand refinedfor over40 years,asdescribedin the different
versionsof the IRE-1EEE standardon piezoelectricity.
The conventional
methodassumes
the piezoelectric
resonatoris nearlymechanicallylossless.This assumptionis valid for somepiezoelectricceramiccompositions,but is inaccuratefor morehighlydampedmaterialsusedin hydrophoneapplications.
New methodsbasedon the measurement
of the real
and imaginaryparts of the complexadmittancehave beendevisedby
Sinits [IEEE Trans. SonicsUltrason. SU-23, 393-402 (1976)] and Sai-
tah et al. [IEEE Ultrason.Symp.Proc. 620-623 (1985) ]. One of these
methodshasbeenacceptedand the parameterfitting routinesimproved
uponto determinethe electromechanical
propertiesof severalimportant
piezoelectric
materialsthat havea high degreeof damping.The importance,applications,
and limitationsof this methodwill be describedfor
thesepiezoelectricmaterials.
A forcedtorsionalvibrationsystem
developed
by theNationalBureau
of Standards[E. B. Magrab, J. Res. Natl. Bur. Stand.89, 193-207
(1984)] for the DavidTaylorNavalShipResearch
and Development
Centeris usedto measurethe dynamicshearmodulusof viscoelastic
ma-
terials.Thecomplex
shearmodulus
G * = G '( 1 + bla ) isdetermined
by
measuring
therelativeamplitudeandphaseat theendsof a harmonically
torquedrightcircularcylinder.Theshearstoragemodulus
andlossfactor
arefoundat frequencies
rangingfrom 50 to 1000Hz for fixedtemperaturesrangingfrom -- 40 øCto 70 øC.An algorithmbasedupontheWilliams-Landel-Ferrymethodof reducedvariables[J. J. Dlubac et al., J.
Acoust.Soc.Am. Suppl.1 82. (1987), precedingabstract]is appliedto
theisothermal
datasetsto generate
curvesof G' and•/Gversusextended
frequency
rangefor a fixedtemperature.
A majorfeatureofthesystem
is
thatthecylindrical
specimen
dimensions
mayrangeupto 10cmindiameter and 15 cm in height.The advantage,of course,is that the effective
complexmoduli of inhomogeneous
materialsmay be determined.For
S101
d. Acoust.Soc. Am. Suppl. 1, Vol. 82, Fall 1987
4:45
•r13.
Surface waves in viscoelastic fluid. H. W. Jones, H. W. Kwan
(Department of EngineeringPhysics,Technical University of Nova
Scotia, Halifax, Nova Scotia B3J 2X4, Canada), and E. Yearman
(Department of Electrical Engineering, Imperial College, London,
United Kingdom)
Viscoelastic
fluidswill, in principle,propagateLamb and Rayleigh
waves.In thesecircumstances,
the shearmodulusis frequencydependent
in both its real and imaginaryparts;therefore,it mightbe expectedthat
someunusualeffectswill occur.In this paper,the propagationof such
wavesby referenceto the viscoelastic
propertiesof crudeoil is described.
Numerical calculationsshowingthe propertiesof thesewavesunder a
rangeof conditions
arepresented.
114th Meeting:AcousticalSocietyof America
S101
THURSDAY
AFTERNOON,
19 NOVEMBER
1987
UMS 4, 1:30 TO 4:20 P.M.
SessionUU. Underwater AcousticsVII: PropagationModeling
Henrik Schmidt, Chairman
Departmentof OceanEngineering,Massachusetts
Instituteof Technology,
Cambridge,Massachusetts
02139
Chairman's Introductinn--l:30
ContributedPapers
1:35
UUI. Numerical modelingtechniquesin underwater acoustics.Paul
C. Etter (ODSI DefenseSystems,Inc., 6110 ExecutiveBoulevard,
Rockville, MD 20852)
A summary
of available
underwater
acoustic
modeling
techniques
is
presented,
emphasizing
thosecomputer-implemented
codesapplicable
principallyto research
in supportof navalsonardesignandoperation.
This comprehensive
summaryaddresses
threemajorclasses
of models:
propagation
loss,noise,andreverberation.
Fifty propagation
lossmodels
arecategorized
according
tofivetheoretical
derivatives
ofthewaveequa-
the orthogonal (u,v) observationplane the caustic has the form
D(u - uc)3= v2.Thepresent
research
isconcerned
withthecaustic
surfacegenerated
by considering
thez dependence
of thecausticparameters
D and uc. Reflectionand transmission
problemsthat lead to this W(x,y)
in theparaxialapproximation
arediscussed
aswell asa novelpropertyof
mergingrays.Soundradiatedby a point sourceso as to reflectfrom a
surface whose height relative to the xy plane is of the form
h•x2+ h•y•x + h3.V2produces
a transverse
cusp.
Thereflected
wavefield
is describedby the Pearceyfunction.Transversecuspsweresimulatedby
reflectinglight from a surfaceof thisform. [Work supportedby ONR. ]
tion:raytheory,multipath
expansion,
normalmode,fastfield,andparabolicapproximation;
furtherdistinctions
aremadebetween
range-independentand range-dependent
solutions.Fourteen noise models are
dividedintothe categories
of ambientnoiseandbeam-noise
statistics;
models
in thelattercategory
arefurthersegregated
according
to analytic
and simulationapproaches.
Fourteenreverberation/active
sonarmodels
arejointlydescribed
in additionto twomultiple-component
modeloperatingsystems;
the reverberation
modelsaredistinguished
according
to
cellandpointscattering
formulations.
Supporting
open-literature
citationsareprovidedto identifyprincipalinvestigators
andinstitutions.
This
summaryaffordsa convenientbaselineagainstwhichto definefuture
developmental
effortsin suchareasashybrid,3-D, broadband,
stochastic,
shallow-water,
andunder-ice
acoustic
modeling.
1:50
UU2. Derivation of higher-order parabolic equations which include
deasityvariations.GeorgcH. Knightly andDonald F. St. Mary(Center
for AppliedMathematicsandMathematicalComputation,Department
2:20
UU4. Resultsof a very-low-frequency
acousticpropagation
experiment
in the Cascadia Basin. Hassan B. Ali, Craig Fisher, Mona
Authcment(NavalOceanResearch
andDevelopment
Activity,NSTL,
MS 39529-5004),andJeff Beckleheimer
(ODSI DefenseSystems,
Inc.,
6110 ExecutiveBoulevard,Rockville,MD 20852)
A series
of very-low-frequency
(VLF) measurements
wereconducted
recentlyby the Naval OceanResearchand Development
Activity
(NORDA) in theCascadia
Basinoff theOregoncoast.Usinga fixed
verticalarrayof 16hydrophones
anda distribution
of oceanbottomseistoometers(OBS), the responses
to cw, explosive,
and air gun sound
sources
weremonitored.
Thepartitioning
ofacoustic
energy
between
the
waterborne
andbottompathsisexamined,
usingtherelativeresponses
of
OBSandwater-column
hydrophones.
Comparisons
between
theexperimentalresultsand predictions
basedon standardnumericalmodelsof
acoustic
propagation
areusedtoascertain
theeffects
onVLF propagation
ofbottomshearandrange-dependent
topography.
of Mathematics,Universityof Massachusetts,
Amherst,MA 01003)
Severalapproachesto the derivationof parabolicequationsare explored,whichincludegeneraldensityfunctions,startingfrom the acoustic waveequationin two andthreedimensions.
In particular,higher-order
(wideangle)parabolicequations
arepresented.
Alsopresented
arefinitedifferencediscretizations
of the equationsthat ( 1) attemptto alleviatethe
needfor specialconsideration
of the "continuityconditions"whenone
fluid mediuminterfaceswith another,and (2) specificallytake into considerationsuchinterfaces.Mathematicalcomparisons
are madebetween
thesetwo approaches.
2:05
UU3. Transversecuspcausticsproducedby reflectionand transmission:
The causticsurfaceandopticalsimulations.
Philip L. MarstonandCarl
K. Frederickson
(Departmentof Physics,
Washington
StateUniversity,
Pullman, WA 99164)
High-frequency
soundreflectedfromcurvedsurfaces
or refractedby
inhomogeneities
mayproducecusped
caustics
thatopenuproughlytransversetothedirection
ofpropagation.
Thoughthebetter-known
longitudinalcuspor areteis produced
by a con9ave
cylindricalwavefront,trans-
2:35
UUS. High-speed normal mode calculations via Milne's equation. F.
J. Ryan (Code541,NavalOccanSystems
Center,SanDiego,CA 921525OOO)
A majorimpediment
to theuseofnormalmodemethodsindeepwater
and/or at high frequencies
is the calculationaltime per mode.A fast,
numericallystablemethodof modecalculationisdescribedwhichisbased
uponMilne'snumericalsolutionof theSchr6dinger
equation.The gistof
Milne'smethodisa phase-amplitude
transformation
of thelinearsecondorder ODE for the modal depthfunctionsinto a nonlinearODE for the
quantum momentum. The resultingnonlinear equation hasimproved nu-
mericalstability,particularlyfor high-ordermodes.In the limit of large
wavenumber,the method reducesto the conventionalJWKB form, but,
unlikeJWKB, it isvalidat turningpoints.An accurateandefficientcomputationalmethodis developedthat yieldssecond-order
convergence
to
aneigenvalue.
Thetechnique
isdemonstrated
forsingleandmultipleduct
sound-speed
profilesand comparedto conventionalpropagatormatrix
approachesfor modalcalculations.
2:50
versecuspsare producedby distinctlynoncylindricalwavefrontsof the
formW(x,y) = -- (a•x2q-az•x q-a3•), wherea2•0andthedistancez
totheobservation
plane• ( - 2a•) - • [Marston,J.Acoust.Soc.Am. 81,
UU6. An efficientenhancement
of finite-differenceimplementations
for
solvingparabolicequations.$. S. Robertson,D.C. Arney (Department
226-232 (1987)]. The wavefront propagatesin the z directionand in
of Mathematics, U.S.M.A.,
$102
J. Acoust.Soc. Am. Suppl.1, Vol. 82, Fall 1987
West Point, NY
10996-1786),
114th Meeting:AcousticalSocietyof America
W.
S102
L. Siegrnann,and M. J. Jacobson(Department of Mathematical
Sciences,
Rensselaer
Polytechnic
Institute,Troy, NY 12180-3590)
The parabolicapproximation
methodis widelyrecognized
asuseful
for accuratelyanalyzingsoundtransmissions
in diverseoceanenvironments. One reason for its attractiveness is because solutions are marched
in range:,
therebyavoidingthe massive
internalstorage
requiredwhen
usingthe full waveequation.Presentimplementations
employa range
stepsizethat is prescribed
eitherby theuseror by thecodeandremains
fixedfor'theduration
of thecomputation.
An algorithm
ispresented
in
whichthe rangestepis adaptivelyselectedby a procedurewithin the
implicitfinite-difference
(IFD) implementation
oftheparabolic
approximation.An errorindicatoriscomputed
ateachrangestep,anditsvalueis
comparedto a user-specified
error tolerancewindow.If the error indica-
torfallsoutside
thiswindow,a newrangestepsizeiscomputed
andused
untilthe.errorindicatoragainleavesthetolerance
window.For a given
tolerance,the algorithmgenerates
a rangestepsizethat is optimalin a
specified.
sense
andwhichoftenleadsto largedecreases
in run time.Additionalrelatedmodifications
to the IFD implementation
will alsobe discussed.
Severalexamplesarepresented
that illustratethe efficacyof the
enhanced
algorithm.[Work supported
by ONR.]
A numericallyefficientprocedurefor findingcompletesolutionsto
wavepropagation
problems
in elasticmediawhoseparameters
dependon
depthonly,butwhereoneof theinterfaces
(e.g.,water/air) isallowedto
vary (undersomerestrictions)with range,is derivedfrom the method
recentlyproposed
byH. SchmidtandF. Jensen.
Thisextension
applies
to
thecasewherethedepthataninterface
expressed
asa function
ofrangeis
a sumofsinusolds.
Theroughness
imposes
energy
coupling
equations
that
mustbesatisfied
bysetsofwavenumber
components
of thepressure
field,
groupedaccording
to thewavelengths
ofthesinusolds.
Theimportance
of
thecouplingdepends
ontheamplitudes
of thesinusoids,
andaccounts
for
al nonevanescent
forwardandbackscattering.
Plane-wave
reflectioncoef-
ficientcalculations
usingthismethodagreewith exactcomputations
basedon work by R. Holford [J. Acoust. Soc. Am. 70, 1116-1128
( 1981) ]. Thisprocedure
isfurtherextended
toallowtheroughinterface,
say, the free surface,to move (under somerestriction) with time, thus
allowinga rapidcompletesolutionof the waveequationincludingfull
Doppler effects.
3:50
3:05
UU7. Etfectsof phaseerrorson pulsesynthesis.David H. Wood (Code
3332,NavalUnderwater
Systems
Center,NewLondonLaboratory,
New
London CT 06320) and Robert P. Gilbert (Center for Scientific
Computation,Universityof Delaware,Newark, DE 19716)
UU10. Roughsurfacescatteringusingtheparabolicwaveequation.Eric
I. Thorsos(AppliedPhysicsLaboratory,Collegeof OceanandFishery
Sciences,
Universityof Washington,
Seattle,WA 98195)
The accuracyof the parabolicwaveequation(PE) for calculating
scatteringfromrandomlyrough,pressure-release
surfaceshasbeenexaminedthroughcomparison
withexactnumericalresultsbasedonsolvingan
One
way
ofmodeling
pulse
propagation
i• theocean
istodecomposeintegral
equation.To facilitate comparisonwith exact results,the PE
the pulseinto a weightedsumof functions
ei•', summedovervarious
values
ofto.Onethen•olvestheHelmholtzequation
numerically
foreach
requiredvalueof to.The weightedsumof thesefieldsthengivesthe desiredresponse
to thepulsein question.
An alternateapproach
solves
the
parabolicequationfor eachrequiredvalueof to,ratherthan the Hclmholtzequation,therebyintroducingphaseerrors.Thesetworesultscanbe
relatedbyanintegraltransform,
or transmutation,
thatconverts
theapproximatesolutionobtainedfrom the parabolicequationinto the true
solutionobtained
fromtheHelmholtzequation.
As a result,corrections
can be made and/or errors can be estimated or bounded.
problemisalsoconverted
to oneof solvingan integralequation:the"PE
integralequation."For the casesexaminedto date,the PE accurately
predicts
lowgrazing
angle(0s<20ø)forwardscattering,
including
multiplescattering
andshadowing
effects.
As thegrazingangleincreases,
it is
foundthat themainerrorisan angularshiftarisingfrompropagation
to
and from the surface,not from the surfacescatteringitself.Finally, a
methodhasbeendevisedto computelow grazinganglebackscattering
with the PE. This requiresthe sequential
solutionof two integralequationsto accountfor multiplescatteringin boththeforwardandbackward
directions.[Work supportedby ONR.]
3:20
UUS. RigorousGaussian-beam
modelingof sourcefunctionsfor•coustic
radiation and propagation.John J. Maciel (Missile SystemsDivision/
RadomeSection,RaytheonCo., Bedford, MA 01730) and Leopold
B. Felsen( DepartmentofElectricalEngineering
andComputerScience,
PolytechnicUniversity,Farmingdale,NY 11735)
Gaussianbeamfunctionshavefavorablepropertiesfor propagating
acousticwavefieldsthroughcomplicatedoceanenvironments.Use of
thesefunctionsin propagation
algorithmsrequiresa decomposition
of the
actualor inducedsourcedistributioninto a superposition
of Gaussian
beams.In implementationsof the "Gaussianbeam method" so far, the
decomposition
isnot uniquebecause
of freelyassignable
parametersin the
beamstack.This causes
difficultieswith a priori predictability[ Lu et al.,
Geophys.J. R. Astron.Soc.(1987); Niver et al., J. Acoust.Soc.Am.
Suppl. I 81, S9 (1987)]. The sourcerepresentation
problemcan be addressed
rigorouslyby performingthe decomposition
on a latticein a discretized(configuration-spatial
wavenumber)phasespace.The formulationof thisdiscretization
scheme[Bastiaans,
Opt. Eng.20, 594 ( 1981) ] is
reviewedand then appliedto radiationfrom a cosineaperturetestfield
distribution.It is shownhow successive
additionof individualdisplaced
and(or) rotatedbeamswith narrow, wide, or "matched"waistssystematicallyhomesin on the independentlycalculatedreferencesolution,althougheachselectionstrategyemphasizes
differentregionsin the phase
space.Tlaeutility of the variousoptionsis discussed,
as are the implicationsfor synthesis
of aperturefieldsfrom measuredfarfielddata.
3:35
UU9. A full wnve solution for propagationin horizontally stratilied
elastic media with full forward and backscatter.Ziad Haddad (AT&T
Bell Laboratories,14A420,WhippanyRoad,Whippany,NJ 07981)
S103
J. Acoust.Soc. Am. Suppl. 1, Vol. 82, Fall 1087
4:05
UUll.
Multiple array processors for three-dimensional •coustic
problems. Yu-chiung Teng (Aidridge Laboratory of
Geophysics,ColumbiaUniversity,New York, NY 10027)
Applied
Presently
available
analytictechniques
for solvingwavepropagation
problems
areonlyusefulforsimplecases.
In realisticcases,
thepresence
of
inhomogeneities
andirregularboundaryconditions
defiesanalyticalsolutions.Oneofthebestnumericaltechniques
suitable
forsolvingwavepropagationproblemsin a complexgeologicalmediumis the finite element
method.In principle,thefiniteelementmethodiscapableof dealingwith
any two- or three-dimensional
acousticand elastodynamic
problems.
However,the computerincorestorageand computingtime for solutions
increasegreatlywith eachdimension
andare beyondthe capabilities
of
theconventional
computers.
It is,therefore,
alwaysdesirable
tosearchfor
alternatives
that mayreducethecomputational
labor.In takingadvantageof thecurrentadvances
in hardwaretechnology,
thegoalisto develop
the finiteelementalgorithmfor an extraordinarily
fastand inexpensive
computersystem.In particular,the implementation
of the finiteelement
methodon multi-arrayprocessor
systemwasconsidered.
The algorithm,
basedonthenodal-podal-point-oriented
approach,
for implementing
the
finiteelementmethodon theparallelcomputation
systemhasbeendeveloped.As a demonstrative
example,the three-dimensional
problemfor the
acousticcasehasbeensuccessfully
testedon the IBM looselyCoupled
Array Processors
(ICAP) by usingoneto eightprocessors.
By usingthe
31X 31X 3l-elementmodelon PRIME 750, the computingtime for 200
time stepsis about 8.8 h and I/O time is 1.7 h. If usingthe ICAPI to
calculatethe samemodel,the elapsetime is about 16.7 rain with two
processors,
8.8 rainwith fourprocessors,
and4.9 min with eightprocesSOLS.
114th Meeting:AcousticalSocietyof America
S103
THURSDAY
AFTERNOON,
19 NOVEMBER
1987
UMS 5, 1:30 TO 4:05 P.M.
SessionVV. Underwater AcousticsVIII: Volume and Object Scattering
C. P. de Moustier, Chairman
ScrippsInstitutionof Oceanography,
Marine PhysicalLaboratory.4-005,La Jolla, California92095
Chairman's
Introduction--l:30
ContributedPapers
1:35
Wl. Averageintensity of an acousticbeamafter propagutingthroughu
turbulent ocean.J. H. Tarng and C. C. Yang (CSSL, Department of
ElectricalEngineering,The PennsylvaniaState University,University
Park, PA 16802)
The averageintensityof an acousticbeampropagatingin a turbulent
oceanisevaluatedusingthepathintegraltechnique.
Because
of theexistenceof the verticalsound-speed
profilein the ocean,thereis more than
onestationarypath for the path integralformulation.Also, thesestationary pathsarecurvedrayswhicharederivedby themethodof ray tracing.
The effectsof randomfluctuations
in soundspeedarestudiedby introduc-
ingbothinternalwavesandtemperature
finestructure.The resultsshow
that the acousticbeambecomes
broaderandasymmetricalongthe vertical axis.The effectsof the broadening,asymmetry,andmultiplestationary pathsare examinedin detail.Interferenceamongmultiplestationary
pathsis expected.In addition,theseresultsare comparedwith thoseof
othersobtainedby usingdifferentapproaches.
[ Work supported
by ARL,
The PennsylvaniaStateUniversity.]
calledp(x),withp= 1corresponding
to6c= 0, wasusedasa measure
of
thedistancebetween
p andp,. Resultsarepresented
ascurvesofp (x) in
dB unitsfor variousfrequencies,
depending
on themagnitudeofrc. It was
foundthatp (x) decreases
monotonically
with range,on theaverage,and
saturatesin rangeat a valuethat decreases
with increasingfrequencyat
therateof about3 dB/oct. The rangeto saturation,calledthe"predictability horizon," is surprisinglyshort for most frequencies
of interestfor
moderate •5c.
2:20
VV4. Modelingof acoustictransmission
in the Straitsof Florida. Charles
L. Monjo and H. A. DeFerrari (Departmentof AppliedMarine
Physics,
RSMAS,Universityof Miami,Miami, FL 33149)
Acoustic
transmission
experiments,
overa 24-kmrangein theStraits
ofFlorida,havebeenmodeled
usingraytheory.Threeacoustic
moorings
andthreethermister
moorings
wereoperated
fora 30-dayperiod.Pulse
responses
(460-Hzcarrierwith100-Hzbandwidth)
wererecorded
every
12rain,andtemperature
at severaldepthseveryhalf hour.Pulseswere
1:50
VV2. Acousticpulsepropagation
in a turbulentocean.J. H. Tarng and
C. C. Yang (CSSL, Department of Electrical Engineering, The
Pennsylvania
StateUniversity,UniversityPark, PA 16802)
Temporalbehaviorof acoustic
pulsepropagation
in a turbulentocean
isinvestigated
by usingthemethodof temporalmoments.In thismethod,
the zeroth, first, and secondtemporalmomentsare related to the total
energyof the pulse,arrival time, and pulsewidth, respectively.To computethesemoments,insteadof the two-frequencymutualcoherence
function, only the coefficients
in a powerseriesexpansion
of thisfunctionare
required.In particular,only thecoefficients
up to the second-order
terms
areneeded.The pathintegraltechnique,incorporated
with themethodof
ray tracing,is usedfor evaluatingthosecoefficients.
The verticalsoundspeedprofileis takeninto account.The turbulencesin the oceaninclude
the internalwavesand temperaturefinestructure.For mathematicalsimplicity,a bilinearsound-speed
profileis considered,
and it is assumedthat
the propagationrangealonga horizontalaxisis short,suchthat the rays
alwaysstayeither aboveor belowthe depthof minimumsoundspeed.
More generalresultscan be extendedeasily. [Researchsupportedby
ONR.]
2:05
VV3. Sensitivity of acoustic fields to environmental uncertainties.
L. B. Dozier, H. Freese, E. S. Holmes, and F. D. Tappert (Science
foundto be highlyvariablein traveltime,duration,andshape.The
MEDUSAraytracingeigenray
modelwasusedtoexplainthepulseformationandvariation,usingthethermister
timeseriesasinput.Model
predictions
of pulseresponses
agreewiththedata.Positive
temperature
anomalies
bringaboutlongdurationpulses,
200ms,whilenegative
temperatureanomalies
bringaboutshortdurationpulses,
50ms.Themechanismbehindthe pulsedurationvariationwasfoundto be a functionof
bottomloss,nota focusing
effectof thesound-speed
profile.Negative
temperature
anomalies
tendtodirectgrazingeigenrays
moresteeply
into
thebottom,causing
greater
bottomlosstothefrontendofthepulse.The
front endof the 200-mspulseis "lost" belowthe noiseleveland a short
duration50-mspulseresults.[Worksupported
by ONR.]
2:35
VVS. Acousticmonitoringand plumemappingof drilling fluid discharge.
John J. Tsai and John R. Proni (NOAA/AOML,
Ocean Acoustic
Division, Miami, FL 33149)
An approachto monitordrillingfluiddischarge
from anoil rig andto
map its plumedistributionby high-frequency
acousticswas proposed.
Experimentswereconductedat two nearbyrigsof the East Flower GardenBank in the Gulf of Mexico,and data wereusedto providevertical
plumestructureand two-dimensional
distributionmapsat fixeddepth.
The ability to monitor the discharged plume continuously in time and
spacemakesthe acoustic
technique
moreconvenient
andcosteffective
than other conventional
methods.
ApplicationsInternationalCorp., 1710GoodridgeDrive, McLean, VA
22102)
2:50
APE model has been usedto compare2D cw acousticfieldsp(x,z)
propagatingin sound-speed
fieldsc(x,z) to a referenceacousticfield
p, (x,z) propagatingin the referencesound-speed
fieldcr(x,z). Samples
of the range- and depth-depeodentsound-speeddifference fields,
6c(x,z) = c(x,z) -- c, (x,z), weregeneratedfrom physicalmodelsof ( 1)
instrumental errors, (2) internal waves, and (3) baroclinic waves (me-
soscale).The squaremodulusofthenormalizedinnerproductoverdepth,
$104
J. Acoust.
Soc.Am.Suppl.1,Vol.82, Fall1987
VV6. The influence of bubbles on sea surface backscatter measurements.
PaulD. Koenigs,JosephM. Monti (Naval UnderwaterSystems
Center,
New London, CT 06320), Bernd Nuetzel, and Heinz Herwig
(Forshungsanstaltder Bundeswehrfuer Wasserschall-undGeophysik,
23 Kiel 14, West Germany)
The resultsfrom a recentseasurfaceacousticscatteringexperiment,
114thMeeting:
Acoustical
Societyof America
$104
whichwasconducted
in theNorthSea,arepresented
withaccompanying
seasurfaceroughness
parameters
andsubsurface
bubbleinformation.
The
acousticdata wereobtainedutilizinga high-resolution
(narrowbeamwidth) pulsedparametric
sonartransmitter
andconventional
receiver.
Scattering
strengthvalueswereobtainedasfunctions
of frequency(3-18
kHz} for windspeeds
from2-45 knots.It appearsthat thebackscattering
strengthat30øgrazingangleiscaused
bythehigh-frequency
wavenumber
spectrumat low wind speedsand by subsurface
babblesat high wind
speeds.
The backscattering
strengthshowsstrongfluctuations
in the intermediateregioncausedby both scatteringmechanisms.
3:05
VV7. Nearfield calculationsfrom elongatedobjectsand a comparison
with the farfield form function.M. F. Werby, Guy Norton (NORDA
Numerical Modeling Div. NSTL, MS 39529), and G. Gaonaurd
(NSWS, White Oak, SilverSpring,MD 20910)
It isusualto examinefarfieldformfunctions
whenexamining
scatteringfromsubmerged
objects.
In thisstudy,whathappeas
whenoneexaminesthe bistaticangulardistributionsin the very nearfieldfor elongated
spheroids
wasdetermined.
The distancefromthefieldisthenprogressively movedfrom the objectin multiplesof the semimajoraxis until the
resultsagreewith the farfieldform function.It isfoundthat thisdoesnot
occuruntil oneis a distancegreaterthan 20 timesthe largestdiameter
fromtheobject.Whenoneiscloseto theobject,thecalculations
reflectthe
fact that a shadowis caston the observerand, therefore,lhe patternis
ratherbroadcloseupandit narrowsasoneprogressively
movesfrom the
object.This lasteffectcanbeobtainedusinga simplegeometrical
expressionthat agreeswith the theoreticalcalculations.
incidence
high-order
components,
that,in turn,rendertheresulting
matfix problemill-conditioned.
Themethodusedin thisstudyispresented
with severalrepresentative
numericalexamples
includingobjectsof aspectratiosof 30 to I for kL/2 valuesto 120.
3'.35
VV9. Scattering from an ellipsoid submergedin the ocean. Michael
D. Collins (Department of Engineering Sciences and Applied
Mathematics, Northwestern University, Evanston, IL 60201) and
Michael F. Werby (Naval OceanResearchand DevelopmentActivity,
NSTL Station, MS 39529)
A timeperiodicsourceandan ellipsoidaresubmerged
in a stratified
oceanseveralkilometersapart.The methodof matchedasymptotics
is
usedto derivean approximate
expression
for thefieldscattered
fromthe
ellipsoid.The matchedasymptotics
solutionconsists
of an innersolution
valid near the scattererand an outer solutionvalid away from the scat-
terer.The two partsof the solutionare matchedin the regionin which
they are both valid. The resultingsolutionis composedof solutionsto
problemsexistingmodelscan handle.The asymptoticlimit appliedto
arriveat theresultrequiresthatthescatterer
issmallrelativeto thedepth
of theoceanandisawayfromtheoceansurfaceandbottom.However,the
methodshouldbe sufficiently
robustto allow theseassumptions
to be
relaxedgreatly.Thismethodisonlyweaklydependent
onfrequency;
the
frequency
mustbeon theorderof 10Hz or greater.[Worksupported
by
ONR and NORDA. ]
3:50
3:20
VV10.
VVS. Eigenvalue methods in the solution of acoustical scattering
problemsfrom submergedobjects.Guy Norton, Richard Keiffer, M.
F. Werby (NORDA Numerical ModelingDiv. NSTL, MS 39529), and
L.H.
Green (Martin Marietta Baltimore, Baltimore, MD 21220)
Waterman'sextendedboundarycondition(EBC) methodhasproven
to beextremelysuccessful
in dealingwith scatteringfromsubmerged
targets.An alternateand usefulcomputational
method(which is relatedto
Enskog'smethod)separatelyconsiders
the Heimholtzintegralequation
at exteriorand interiorpoints,as doesthe EBC method.However,the
interiorproblemcan be shownto transformto an eigenvalue
problem,
whichproduces
eigenstates
thatspanthespaceof thedisplacement
onthe
objectsurface.The eigenstates
canbe useddirectlyto solvethe exterior
problemandyielda numericallys•ablcandconvergent
solution.This new
methodavoidsproblemsencountered
by the EBC method.For example,
in theusualEBC approach,the unknownsurfacetermsareexpandedona
known,but to someextentarbitrary,basisset,with unknownexpansion
coefficients.
The numberof expansiontermson the surfaceand thoseof
the incidentpartialwavesmustmatch.Computationally,
this requirement can often dictatethere be many more incidentpartial wavesthan
strictlyrequiredfor convergence
of theincidentfield.This leadsto small-
S105
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall 1987
Limitations
of meclmnieal struetares as wave vector filters.
Y.F. HwangandG. Maidanlk(David Taylor NavalShipR&D Center,
Bethesda,MD 20084)
Althoughthe high-wavenumber
contentin a highlysubsonic
(low
Mach number) turbulentboundarylayer (TBL) is knownwith reasona-
blecertainty,theIow-wavenumber
contentis not.In a wavevectorfilter
chosen
anddesigned
tomeasure
theiow-wavenumber
contentofTBL, the
majorsensitivity
regionis appropriately
placedin that spectraldomain.
Inevitably,someminorsensitivity
regionslie in the high-(convective)
wavenumber
region.Theseminorsensitivity
regionsare thenfedby the
spectralpressure
ridgein theTBL. Thisfeedingmaysubstantially
contaminatethemeasurements.
The properchoiceandthenoveldesignof a
filterisjudged,byandlarge,byitsabilityto subdue
suchcontamination.
In thispaperwavevectorfilters,for measurements
of theIow-wavenumbetcontentof TBL, asprovidedby idealrectangular
andcircularpanels,
are comparedand contrasted.
In thisexamination,
the contamination
caused
bythehigh-wavenumber
contentin theminorsensitivity
regionsis
estimatedby simulatingit as a 1ow-wavenumber
contentin the major
sensitivity
region.Theseestimated
equivalent
1ow-wavenumber
contents
constitutethe lower boundsthat the wave vector filters are capableof
measuring.
114thMeeting:AcousticalSocietyof America
S105
FRIDAY MORNING, 20 NOVEMBER 1987
TUTTLE CENTER ROOM, 8:25 TO 11:30A.M.
SessionWW. PhysicalAcousticsVIII: AcousticLevitation
Anthony A. Atchley, Chairman
Department
of Physics,
Code61.4E NavalPostgraduate
School,
Monterey,
California93943
Chairman's Introduction---8:2$
ContributedPapers
8:30
WW1. Acousticlevitation at high temperaturesin the microgravityof
space.CharlesA. Roy,DennisR. Mcrklcy,GregoryR. Hammarlund,
and ThomasJ. Danley (Intersonics,Incorporated,3453 Commercial
Avenue, Northbrook, IL 60062)
ysistakesinto accountacousticradiation,surfacetension,gravity,and
compressibility
effects.
Salientfeaturesof thistheoryapplicable
to acoustic levitationwill be presented.
Calculatedshapeproperties
will be comparedto existingresultsof one-dimensional
theories.Also,the acoustic
forcedependence
onks, obtainedfromequilibriumpositioncalculations,
will becompared
to Hasegawa's
results.[ Worksupported
by NASA.]
Acousticlevitationof a smallspecimen
is obtainedin theenergywell
produced
bya singleaxisarrangement
consisting
ofa soundsource
anda
small acousticreflector.At high temperatures,the acousticforcesare
9:15
generallyinsufficient
to levitatea specimen
exceptin the microgravity
environmentavailablein space.A singleaxisacousticlevitator(SAAL)
hasbeenbuilt to levitatea specimen
insidea high-temperature
furnace
whereit may be heated,melted,cooled,and solidifiedwhilebeingpositionedwithoutphysicalcontact.Theacoustic
fieldconfiguration
in sucha
containerless
processing
devicehasbeenanalyzedandtheexpected
levitationor positioning
forcesarecalculated
forthespecific
caseoftheNASASAAL experimental
hardwareasflownon theSpaceShuttleon theSTS6 IA mission.Thisexperiment
successfully
levitatedandprocessed
three
samples
at temperatures
from600øCto 1550øC.Experimental
dataare
presented
andtheresults
compared
withthosepredicted.
[Worksupported by NASA. ]
8:45
WW4. Boltzmann-Ehrenfest adiabatic principle applied to acoustic
forces in a single-modelevitator. S. Putterman, JosephRudnick
(PhysicsDepartment,Universityof California,LosAngeles,CA 90024),
and M. Barmatz (Jet PropulsionLaboratory,CaliforniaInstituteof
Technolgy,Pasadena,CA 91109)
An application
of theBoltzmann-Ehrenfest
adiabaticprincipleyields
a fundamentalrelationship
betweenthe acousticpotential,actingon a
sample
positioned
ina single-mode
cavity,andtheshiftintheresonance
of
an isolatedmode.The theoryis verygeneraland appliesto a sampleand
resonantcavityof arbitraryshapeand dimension.In the caseof a small
samplein a lossless
cavity,thestrictproportionality
between
thepotential
and frequencyshift followsfrom a fairly simpleargument.One useful
application
of thisrelationship
is thedetermination
of positioning
forces
and torqueson a leviratedsamplefrom frequencyshift measurements.
The resultsof experimentalmeasurements
of the equilibriumpositionand
WW2. Acousticlevitationin the presenceof gravity. M. Barmatz (Jet
Propulsion
Laboratory,CaliforniaInstituteof Technology,
Pasadena,
CA 91109) and P. Coilas (Department of Physicsand Astronomy,
CaliforniaStateUniversity,Northridge,Northridge,CA 91330)
orientationof a levitatedsamplewill bepresented,
andtheirconsistency
with theoreticalpredictionswill be discusssed.
[Work supportedby
NASA. ]
A theoryof acousticlevitationin the presence
of gravityhasbeen
developed
for arbitrarilyorientedchambers
of rectangular,
cylindrical,
andspherical
geometries.
Simultaneous
modeexcitation
wasalsoincludedin theanalysis.
Examples
ofthetotalpotentialandforceprofilewill be
givenforcommonly
usedlevitation
modes
asa functionofchamber
orien-
WWS. Theory of oscillational instabilities in acoustic levitators.
tation. Additional levitationpositionsare obtainedwithin the chamber
CaliforniaInstituteof Technology,Pasadena,CA 91109)
for appropriately
chosenmodesand orientations.
Levitationpositions
withina chamberwheretheacousticforcesareisotropicwill bepresented
for the caseof small kR. The effectsof modedegeneracyon the total
potentialandforcefor thecaseof thetripleaxislevitatorflownon the
SpaceShuttlewill alsobediscussed.
[ Worksupported
by NASA.]
9:30
JosephRudnick(PhysicsDepartment,Universityof California,Los
Angeles,CA 90024) and M. Barmatz(Jet Propulsion
Laboratory,
A generaltheorydescribes
theoscillationalinstabilities
of an acousti-
callylevitated
sample
in a resonant
cavity.Thetheory,based
ona Green's
functionmethod,predictsthe onsetof instabilities
and their saturation.
Important
factors
controlling
theseinstabilities
inculde
drivefrequency,
spatialstructure
of thelevitation
mode,andthesizeof thesample.
The
instability
in a zerogravityenvironment
hasfundamentally
different
onsetcharacteristics
thanin finitegravity.Calculations
revealhysteresis
and
saturation
effects.
Manyof thepresent
results
areconsistent
witha pre9:00
WW3. Shapeof acousticallylevitated samplesin a resonantrectangular
chamber.H. W. Jackson,M. Barmatz,and C. ShipIcy(Jet Propulsion
Laboratory,California Instituteof Technology,Pasadena,CA 91109)
A generalizationof Laplace'sformulaapplicableto vibratingsurfaces
wasusedto developexpressions
for the equilibriumshapeand positionof
dropsandbubblesin a resonantrectangularchamber.Expandingvarious
physicalquantitiesin termsof sphericalharmonicsand applyingthe
quantum-mechanical
angular-momentumgradient formula leads to
tractableexpressions
valid for largeas well as small ks. New resultsfor
volumerenormalizationof dropsandbubbleswerealsoderived.The anal-
S106
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
viouslydeveloped
empiricalmodelof theinstabilities
[S. L. Garrettand
M. Barmatz,
J.Acoust.
Soc.Am.Suppl.177,S21(1985)]. Typicalexamplesof theaboveeffects
will bediscussed.
[ Worksupported
by NASA.]
9:45
WW6. Eigenfrequenclesof axisymmetric cavities: Numerical
calculations.Arthur E. Woodling and James B. Mehl (Physics
Department,Universityof Delaware,Newark,DE 19716)
The eigenfrequencies
of axisymmetric,
hard-walledacousticcavity
resonatorshavebeencalculatedby usingan integral-equation
represents-
114thMeeting:Acoustical
Societyof America
S106
tionof theHelmholtzequation
withNeumannboundary
conditions.
For
axisymmetric
shapes,
theintegralequation
is one-dimensional.
Numeri-
calresulnas
havebeenobtained
fora perfect
sphere,
andforslightly
deformedspheres,
andfor cylinders
withan internalsphere
onaxis.The
results
forslightly
deformed
spheres
arein close
agreement
withthepredictions
ofboundary-shape
perturbation
theory,
fromwhichtheytypically differbylessthan6 partsin 106.Theresults
forcylinders
withinternal
ference
fieldthathascapabilities
forthelevitationandpositioning
ofsmall
objectsor liquiddrops.The theoreticalpredictions
regardingthistechniqueareexaminedandthoseresultsarecompared
withlaboratorymea-
surements.
The natureof the apparatus
andits capabilities
is alsoaddressed.[Work supported
by NASA.]
spheres
areinexcellent
agreement
withmeasurements
[M. Barmatzetal.,
J. Acoust.Soc.Am. 73, 725-732 (1983)].
10:45
10:00
WW7.Perturbation
calculations
ofeigenfrequencies
ofcylindrical
cavity
with internal sphericalobstacle.JamesB. Mehl and Robert N. Hill
(Physics
Department,
University
of Delaware,
Newark,DE 19716
)
Theeigenfrequencies
ofa hard-walled
acoustic
resonator
arefoundby
solvingtheHcimholtzequationwithNeumannboundary
conditions.
A
cavityCwithaninternal
hardobstacle
Bofvanishing
sizewasconsidered.
As thesizeof theobstacle
shrinksto zero,theeigcnfunction
doesnot
approach
ancigenfunction
oftheemptycavity.
Thusasingular
perturbationtheory
isrequired.
A formalism
wasdeveloped
andtested
bycalculatingtheeigenfrequencies
ofa cylinder
withaninternal
sphere
ontheaxis.
Theresults
arecompared
withtheoretical
values
determined
bya bound-
sty-integral-equation
method
(A. E.Woodling,
Ph.D.thesis,
University
WWI0. Specimentranslationalcontrolcapabilitiesusingan oppo•l
radiatoracouaticlevitationsystem.
DennisR. Merkley,CharlesA. Rey,
Gregory R. Hammarlund, and Thomas J. DanIcy (Intersorties,
Incorporated,3453 CommercialAvenue,Northbrook,IL 60062)
Recentdevelopments
on an opposed
sound-source
single-axis
acousticlevitation
system
arediscussed.
Newandimproved
specimen
positioningcontrolcapabilities
aremadeavailable
byparametric
variations
ofthe
electronic
drivesignals.
Variousmethods
aredescribed
in whicha specimencanbeheldin onepositionor translated
alongtheaxisof thelevitationbysimpleelectronic
controlsignals.
A technique
isalsodescribed
to
provideincreased
specimen
positioning
stabilityusinga closedloopsystem. [ Work supported
by NASA. ]
of Delaware,1986)andexperimentally
[M. Barmatzet al., I. Acoust.
Soc.Am.73,725-732( 1983) ]. [Worksupported
in partbyNASA.]
11:00
10:15
WW8. Eigenfrequencies
of a cylindricalcavity with an internal off-axis
sphericalobstacle.M. Barmatz,G. Avcni (Jet PropulsionLaboratory,
California Institute of Technolgy,Pasadena,CA 91109), and James
WWII. Enhancedacousticlevitationusinghorn loadedand faeusing
radiators.ThomasJ. DanIcy,CharlesA. Rey, DennisR. Merkley,and
GregoryR. Hammarlund (Intersorties,Incorporated,3453Commercial
Avenue, Northbrook, IL 60062)
19716)
An improved piezoelectricdriven, focusingacousticradiator for
acousticlevitationhasbeendesigned,tested,and evaluated.This device
A hard sphericalobstacleis mountedinsidea cylindricalcavityat a
variableposition.The resonancefrequencies
of the cavity were deter-
displays
a significant
improvement
in focusing
toproduce
betterspecimen
stabilityandenergywell shapingaswell asincreased
transducer
power
bandwidthandelectroacoustic
conversion
efficiency.
Corresponding
ef-
B. Mehl (PhysicsDepartment,Universityof Delaware,Newark, DE
minedasa functionof theposition
ofthesphere
forobstacle
positions
on
andofftheaxisof thecylinder.Thedependence
of theresonance
frequencyonthespherepositionisimportantin analyzingthestabilityofacousticallylevitatedsamples.
Theresultsarein goodagreement
withtheoretical
calculations
basedon the singularperturbationtheoryof Mehl and Hill.
Themeasurements
will alsobecompared
to a newtheorythatutilizesthe
fectsresultingfrom thehornloadingof thisacousticradiatorareconsideredas well as the benefitsof usingthe radiatorin conjunctionwith hot
wall high-temperature
furnaces.In orderto aid in theevaluationof these
acoustictransducerimprovements,
a simpleand usefultechniquefor
acousticfield mapping will also be discussed.[Work supportedby
NASA. ]
Boltzmann-Ehrenfest
adiabaticprincipleto predictthe spatialdependeneeof tlheacousticpotentialfrom the resonance
frequencies.
[Work
supportedby NASA. ]
11:15
10:30
WW12. Enhancements
of acousticlevitationin thepresence
of increased
gas pressure.Gregory R. Hammarlund,DennisR. Merklcy, Charles
A. Rey, and Thomas J. DanIcy (Intersonics,Incorporated,3453
WW9. A newacoustic
levitationdeviceusingtheinterference
soundfield
generatedfrom two opposedradiators.Charles A. Rey, Thomas
J. Danley, Dennis R. Merkley, and Gregory R. Hammarlund
(Intersonies,Incorporated,3453 CommercialAvenue,Northbrook,IL
60062)
A newtechniquefor acoustically
levitatinga specimen
is described.
The technique
deviatesfrom a previoussingle-axis
acousticlevitation
methodthatutilizesa single-acoustic
radiatoranda passive
reflector
to
generate
theinterference
produced
soundfield.Thenewmethodinvolves
theuseoftwoopposing
focusing
acoustic
radiators
thatproduce
aninter-
S107
d.Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
CommercialAvenue, Northbrook, IL 60062)
Acousticlevitationfor containerless
materialsprocessing
hasbeen
investigated
for usein the 1-genvironment.Enhancements
havebeen
obtainedby increasing
thegaspressure
of theacousticlevitationsystem.
Interdependence
of gaspressure,
soundpressurelevel,acousticpositioningforce,andgastemperaturehasbeenmeasured.
Also,nonlinearacoustic effectsand harmonic content within the acoustic field are examined as
a functionof pressure.
Finally,resultsof l-g acoustic
levitationexperimentsutilizingincreased
gaspressures
arepresented.
[ Work supported
by NASA. ]
114thMeeting:Acoustical
Societyof America
S107
FRIDAY MORNING, 20 NOVEMBER 1987
UNIVERSITY LECTURE HALL, 8:30TO 11:30A.M.
SessionXX. Psychological
andPhysiologicalAcousticsVIII: BinauralHearing
Leslie R. Bernstein, Chairman
Department
of Psychology,
Psychoacoustics
Laboratory,
University
of Florida,Gainesville,
Florida32611
Contributed Papers
8:30
XX1. Ear advantagesfor monaural periodicity detection. James
A. Bashford,Jr. and Richard M. Warren (Department of Psychology,
Universityof Wisconsin-Milwaukee,Milwaukee, WI 53201)
Monauralasymmetries
werefoundfor periodicitydetectionin experimentsusingrepeated200-mssegments
of Gaussiannoise(repetitionfrequency5 Hz). In experiment1,anoverallleftearadvantage
wasfoundfor
repeatednoisedeliveredmonaurallyandopposed
bycontralateralsilence.
In experiment2, lateralizationof the monauralsignalwas abolishedby
simultaneouspresentationof on-line noiseto the oppositeear (contralateral inductioncausedthe monauralsignalto be perceivedascenteredon
the medialplane). Althoughthis manipulationeliminatedthe possible
influenceof attentionalbiasesfavoringone of the sides,ear advantages
werestill obtained.Alternativemechanisms
will be discussed,
including
possible
asymmetries
in activesubcortical
processing
of periodicityinformation. [Work supportedby AFOSR.]
8:45
XX2. Binaural envelopecorrelationdetectionas a functionof frequency
separation. Virginia M. Richards (PsychoacousticsLaboratory,
Department
ofPsychology,
University
ofFlorida,Gainesville,
FL 32611)
Recentcomodulationmaskingrelease(CMR) experimentssuggest
that listenersareableto determinewhetherthe envelopes
of dichotically
presented
bandsof noiseare temporallysimilar(no signal)or different
(signaladdedtooneofthetwobands,
ofnoise).In anefforttodetermine
thesensitivity
to changes
in envelope
synchrony
asa functionof thefrequencyseparation
of the twobandsof noise,listeners
discriminated
be-
masker
asafunction
ofthesignal
onset'time.
Themasker
ispreceded
by
quietor an Nrrforwardfringeandfollowedbyquiet,an No, or Nrcbackwardfringe.Overall,theresultsarecompatible
witha forwardmasking
interpretation.
Further,whenthesignalonsetis simultaneous
with the
onsetof the 20-msmasker,the Nrr forwardfringereducesdetectability.
[Work supported
by NSF andAFOSR.]
9:15
XX4. Further research on free-field masking. R. Wayne Gatehouse
(Department of Psychology,University of Guelph, Guelph, Ontario
N1G 2W1, Canada)
Gatehouse(Proc. 12th Int. Congr. Acoust.,B2-7, 1986) compared
free-field masked and unmasked thresholds (two-alternative forced-
choiceprocedure)with a WN musketfixedat 0øwhile5 tonalprobeswere
deliveredfrom 11 frontal planepositions.Maskingwasnot necessarily
greatestfor masker-signal
coincidence
butvariedwith frequencyandsignal position.For 1.0- and 2.5- kHz signals,detectabilitywas best and
approximately
equalat 0øand + 90ø,whilefor theothers(0.25, 0.5, and
4.0 kHz) therewcrcgenerallylowerthresholdsassignalandmaskerseparated.The taskwasrepeatednowwith 0.5-, 1.0-,and2.0-kHz probesand
themusketsetat 0øand + 45ø.Again,free-field
maskingvariedwithboth
signalpositionand frequency,and bestand leastdetectionwasnot solely
determined
byazimuthalseparation
of themaskerandsignal.On average,
maskingleveldifferences
wereapproximately
24.0dB for 0.5-, 11.5dB for
1.0-,and 13.5dB for 2.0-kHz signals.The apparentdifferences
between
earphone-derived
and free-fieldmaskedthresholds,which seemmore
subjectto frequencyand positionalvariations,will bc discussed.
tweennoisebandswhoseenvelopes
wereeitheridenticalor statistically
independent.
The noisebandswere100Hz wide.Thebandpresented
to
the left ear wascenteredat 2625 Hz; the bandpresentedto the fight ear
wascenteredat valuesbetween2625 and 5250Hz. Althoughtherewere
9:30
considerable individual differences, discriminations tended to be best
whenbothnoisebandswerecenteredat 2625Hz. Increasingthe frequency separation
betweenthetwo bandsof noiseledto poorerperformance,
but the percentage
of correctresponses
remainedabove60. Subsequent
experiments
indicatethatthediscrimination
isbasedonenvelope
similarity ratherthanthesimilarityofthepowerspectrum.
[Research
supported
XXS. Resolutionof pairsof simpleand complexsoundsin simulated
auditory space.Pierre L. Divenyi and SusanK. Oliver (Speechand
HearingResearch,
V.A. MedicalCenter,Martinez,CA 94553)
by NIH. ]
obtaining,in 5-degazimuthalsteps,externalear transferfunctions
for
bothearsofan artificialheadplacedin ananechoic
room.Whenanarbitrarysoundispassed
throughthedigitalfilterdefined
bytheleftandright
transferfunctions
corresponding
toa givenangle,thesoundwillacquirea
9:00
XX3. Effects of forward masker fringe on binaural detection. B.
D. Simpson
and R. H. Gilkcy (SignalDetectionLaboratory,Central
Institute for the Deaf, Saint Louis, MO 63110)
Yost [J. Acoust.Soc.Am. 78, 901-907 (1985) ] foundthat detectability of a 20-msdichoticsignal(S•r) in a 20-msdioticnoise(No) wasnot
affectedby thepresence
of a 500-msdichoticforwardfringe(Nrr). However, Kollmeier and Gilkey [J. Acoust. Soc. Am. Suppl. I 74, S39
(1982)] variedtheonsettimeof a 20-msS•' signalin a 750-msnoisethat
switched,after 375 ms, from N•r to No, and found that the N•r noise
reduceddetectabilityevenwhenthe signalwaswell into the No noise.
Theyconcluded
that the N•r noiseactedasa forwardmasker.The present
studyinvestigates
detectability
ofa 500-Hz,20-msS•rsignalin a 20-msNo
$108
J.Acoust.
Soc.Am.Suppl.1,Vol.82,Fall1987
A simulated
acoustic
replicaof a soundsourcemovingalonga circle
with a 4-m radiusin the frontal horizontalhalf-planewasgeneratedby
subjective
azimuthcomparableto whichthe transferfunctionwasmeasured[J. BlauertandP. Laws,Acustica29, 273-277 (1973) ]. This tech-
niquewasusedto measure
resolution
thresholds
for pairsof amplitudemodulated
aswellaspuresinusolds.
With thelistenerrequiredto identify
the relative location of the two soundsin a two-alternative forced-choice
paradigm,in onesetof experiments
the two soundswerefixedandthe
minimumaudibleangularseparation
wasobtained,whereas,in another
set,the angularseparation
wasfixedand the minimummodulation-or
carrier-frequency
separation
wasmeasured.
Generally,
bothkindsof resolutionare better around0 azimuth than at the sides:In the "auditory
fovea,"simultaneous
resolution
for puretonesandAM sounds(a 3- or 6kHz cartiersinusoidally
modulatedinthe 150-to 400-Hzrange)isalmost
asgoodasthejndobtained
intheusualsequential
presentation.
Thepoor-
estspatialresolution
wasobtained
fora pairof6-kHzcarriers
modulated
114thMeeting:
Acoustical
Society
ofAmerica
S108
by a 100-anda 400-Hz sinusoldandthe bestfor pairsof AM toneswith
differentcarriers.[Work supportedby the VeteransAdministrationand
by a NATO TravelFellowship.
]
10:00
XX7. Psychophysical
factorsof spatial impression.Frans A. Bilsen,
Herman W. Kruysse, and JohanRaatgever (Applied Physics
Department,
Delft University
of Technology,
Delft,The Netherlands)
Spatialimpression
(or spaciousness)
is animportant
perceptual
attributein roomacoustics,
implying( 1) the sensation
of a listenerin a
concert
hallof beingenveloped
bythesoundfieldand(2) theperceived
broadening
of the soundsource.A psychophysical
experiment
will be
9:45
reportedusingdichoticpresentation
of (filtered) white noise,in which
XX6. The enhancement
of binauralsourcelocationby scubadivers.
Stewart A. L. Glegg, JohnKloske, ChrisHansen,and Terry
R. Johnson(Departmentof Ocean Engineering,Florida Atlantic
University,BocaRaton, FL 33431)
This paperwill describethedevelopment
of a passivesourcelocalization device to enhancethe ability of scubadivers to locate acoustic
sources.
The deviceconsists
of a hat that is wornby thescubadiversand
providesa distinctnull in the observedacousticfield whenthe diver is
facingtheacoustic
source.
Testswerecarriedoutin a 25-ft-deep,198-ftdiam tank at the EPCOT Centerin Orlando,FL on 25 subjects.
The
resultsof thesetestsshowthat thereis a clearimprovement
usingthis
device,whichiscomfortable
to wearandsuitablefor mostapplications.
theinfluence
on spatialimpression
wasinvestigated
of threesignalvariables,viz., theinterauralcorrelation,thecenterfrequency,
andtherelativebandwidthof thefilteredversions
of thenoise.Eightuntrainedsubjectsparticipatedin a scalingexperiment:
They werepresented
4 times
with 80 (4.5.4) experimentalconditions;subjectivecriterionwas the
perceived
widthof thesoundimage.Therawordinaldatawereanalyzed
by canoniccorrelationanalysis(CANALS); on the resultingdata,
ANOVA wasapplied.The mainoutcomeof the experimentis that the
interauralcorrelation
andthecenterfrequency
areindependent
andadequatepredictorsof spatialimpression.
This resultandtheresultsof other
experiments
will beinterpreted
in thecontextof existing
binauraltheories.[Work supported
by theNetherlands
Organization
for theAdvancement of Pure Research(ZWO). ]
10:15-10:30
Break
10:30
XXS, Effectsof rovinglevel onbinauraldetectionand discriminationon
andoff l•Mdline.
J. KoehnkeandH. S. Colburn(Research
Laboratory
of Electronics,
Massachusetts
Institute
ofTechnology,
Cambridge,
MA
02139 and BostonUniversity,48 CummingtonStreet,Boston,MA
02215)
falsealarm rates,whereassignificantcorrelationsfor both rateswere re-
portedfor thewidebandexperiment.
The lackof effectof targetphaseon
hit rate in the narrow-band NoS•' condition is inconsistent with models
basedon lateralpositionbut consistent
with the EC modelandwith models usingthe sumof the squaresof interauraltime and intensitydifferences.[Work supportedby NIH.]
NoS•rdetection
thresholds
andinteraural
timeandintensity
jnd's
weremeasured
bothwithandwithouta 10-dBrandomroveappliedtothe
11:00
overalllevel.The stimulusfor discriminationandthe maskerfor detection
werea l/3-octnoise
bandcentered
at500Hz;fordetection,
thetargetwas
a 500-Hztoneburst.Thresholds
andjnd'sweremeasured
using
anadaptive,four-interval,
two-alternative
forced-choice
procedure
forseveral
interaural
timeandintensity
reference
conditions
including
differences
of0
and24dBand0 and600gs.Results
indicate
noeffectofrovinglevelfor
the0-dB,0-psreference
conditionfor binauraldetectionor interaural
discrimination.
ForNoS•'detection,
thereisnoeffect
of rovinglevelor
reference
conditionon thresholds.
For interauraltimediscrimination,
jnd'sarelargeroffmidlineandrovinglevelvariationhasnoconsistent
effect
onperformance.
Forinteraural
intensity
discrimination,
jnd'sgenerally increaseoff midlineand are usuallylargerwhenmeasuredwith
rovinglevelthanwithout.[Work supported
by NIH.]
10:45
XX9. Effectsof target phasein narrow-bandfrozennoisedetectiondata,
S.K. Isabelle
andH. S. Colburn(Biomedical
Engineering
Department,
BostonUniversity,110 CummingtonStreet,Boston,MA 02215 and
Research Laboratory of Electronics, MassachusettsInstitute of
Technology,
Cambridge,MA 02139)
Hit and falsealarm rateswere estimatedfor detectionofa 500-Hz tone
XX10. Lateralization
on the basisof interauralenvelope
delays:The
effectof additional
frequency
components.
RaymondH. Dye,Jr. and
AndrewJ. Niemiec(ParrelyHearingInstitute,LoyolaUniversity,
6525
North SheridanRoad,Chicago,IL 60626)
A lateralization
experiment
wasperformed
in whichthresholdinter-
auralenvelope
delays
weremeasured
asa function
ofmodulation
frequency (fm = 25, 50, 100, 200, 300, 400, and 500 Hz) for three- and five-
component
complexes
whosecenterfrequency• } waseither2000 or
4000 Hz. A two-alternative
forced-choice
procedure
wasusedin which
the envelopelaggedto the right ear duringoneintervaland to the left
intervalduringtheother.The levelof eachcomponent
was50 dB SPL,
andthesignaldurationwas200mswith 10-mslinearrise-decay
times.
Thresholds
obtained
with three-andfive-component
complexes
were
quitesimilarregardless
offro, a findingthatseemed
consistent
withthe
notionthattheenvelope
isextracted
fromcomponents
interacting
within
anauditory
filter,withmoredistalcomponents
having
noeffect.
Surprisingly,makingtheoutermost
sidebands
(f• - 2f• andfc + 2f• ) riotic
wasfoundtoseverely
impareone'sabilitytoutilizeenvelope
delays
even
whenthef• 's werequitehigh.Thesefindings
placein doubtthecontentionthatthebinaural
auditory
system
extracts
envelopes
bymonitoring
the outputsof narrow-band
auditorychannels.[Work supported
by
NINCDS and AFOSR. ]
targetin eachoften samples
of l/3-oct noisecenteredat 500Hz for both
NoS•randNoSoconditions.
Theeffects
oftargetphase(0øand90ø)onhit
ratewereinvestigated
forthreesubjects.
Resultsforthisnarrow-band
case
weresimilarto previously
reportedresultsforwidebandmaskers[Gilkey
etal., J. Acoust.Soc.Am. 78, 1207-1219(1985) ]. Two differences
were
noted.First,forNoS•'conditions,
theeffectofsignal
phase
wasnotsignificantforthenarrow-band
maskers,
whereas
a smalleffectwasreported
for wideband
maskers.
Second,no significant
correlation
wasobserved
between NoSo and NoS•r results across masker waveforms for hit and
S109
J.Acoust.
Soc.Am.Suppl.1,Vol.82,Fall1987
11:15
XXI1. Interaural envelope correlation and the high-frequency MLD.
Leslie R. Bernstein (Psychoacoustics
Laboratory, Department of
Psychology,Universityof Florida, Gainesville,FL 32611)
Data from a numberof investigations
suggestthat listenersare extremelysensitiveto interauraltemporaldisparitiesin the envelopes
of
114thMeeting:
Acoustical
Society
ofAmerica
S109
configurations
includingNoSo,NoSre,andNoS•rat a centerfrequency
of
3571Hz. In addition,a sinusoidally
amplitude-modulated
3571-Hz tone
dioticmaskingnoiserangedfrom50to400Hz. For all conditions,
dichotic thresholdswere accountedfor quite well by assumingthat, for each
listener,detectionoccurswhenthesignaldecreases
theinterauralcorrelationof theenvelope
of thenoiseto somethresholdvalue.This findingas
wellasalternative
explanations
will bediscussed
in termsofmodernmodelsand theoriesof binauralhearing.[Researchsupportedby Air Force
whosecarrier wasinteraurallyin phasebut whosemodulatorwas inter-
Officeof ScientificResearch.]
high-frequency,
complex
waveforms.
In thepresent
study,anattemptwas
madeto assess
whetherthis sensitivitycouldbe the basisfor MLDs obtainedat high frequencies.
An adaptive,two-alternativeforced-choice
task was used to estimate detection thresholds for a number of interaural
aurallyphase-reversed
wasemployedas a signal.The bandwidthof the
FRIDAY MORNING,
UMS 4 AND 5, 8:30 A.M. TO 12:00 NOON
20 NOVEMBER 1987
SessionYY. UnderwaterAcousticsIX: Bottom Interacting Ocean AcousticsI
David R. Palmer, Chairman
NOAA--AtlanticOceanographic
andMeteorological
Laboratory,
4301Rickenbacker
Causeway,
Miami,Florida33149
Chairman's Introduction--8:30
Invited Papers
8:35
YYI. Acousticiasuesfrom a marinesurveyor'sviewpoint.WesleyV. Hull (Chartingand GeodeticServices,
National Ocean Service,NOAA, Rockville, MD 20852)
Theships
andinstrumentation
usedin theNationalOceanService
hydrographic
andbathymetric
surveyingrepresent
capitalinvestment
of severalhundredmilliondollarsandrecurringannualcostsof tensof
millions.Theefficiency
in surveycoverage,
whilemaintaining
requiredsurveyaccuracy,
isof utmostconcern.
Deficiencies
inanyoftheseveral
typesofacoustic
systems
usedinthesurveys
cananddocontribute
significantly tothelossofsurvey
production.
Thispaperdescribes
brieflythreetypesofsurvey
missions,
highlighting
the
acoustic
systems
usedandtheknownor preceived
acoustic
phenomenological
factorsthatcontribute
to lost
production.
Thesesystems
include
dualfrequency
echosounders,
multibeam
swathsonarsystems,
andconventionalsidescan.The paperalsodiscusses
emerging
technology,
now underconsideration,
includingboth
intefferomctricand multibeamsidescansystems,againwith emphasison the critical acousticphenomena.
Finally,a newconcept
dubbed
"theacoustic
knife,"forwhichanexperimental
project
isnowcontemplated,
is
discussed.
9:00
YY2. Scattering
of soundfromtheroughseafloor.
T. K. Stanton(Departmentof GeOlogy
andGeophysics,
Universityof Wisconsin,Madison,WI 53706)
Thescattering
of soundfromtheroughseafloor
andresultantechofluctuations
arefunctions
of seafloor
geomorphology
andsonarparameters
suchasbeamwidth,
frequency,
andangleofincidence.
Thescattering
is
verydifficultto describe
analyticallyandquiteoftenrequiresnumericalandempiricaltechniques.
Like most
roughinterfaces,
theseafloor
canbedescribed
bytwoclasses
ofsurfaces:
( 1) stochastic
and(2) deterministic.
For bothtypesof surfaces,
it is essential
to modeltheroughness
asbeingtwo-dimensional,
i.e.,notstriated.
Because
of therandomness
of theseafloor,theechowill fluctuatefrompingto pingasthesonarmovesoverthe
floor.Patchesor distinctgeomorphological
featureswill causedeviationsin the statisticalproperties
of the
echoes.[ Work supported
by theONR. ]
9:25
YY$. Inversemethodsin oceanbottom acoustics.GeorgeV. Frisk (Department of OceanEngineering,
WoodsHole OceanographicInstitution,WoodsHole, MA 02543)
A reviewispresented
ofexactandperturbative
inversemethods
usedtodetermine
theacoustic
properties
of
thebottom.The discussion
concentrates
primarilyoninversions
for propertiesin thetopfewhundredmetersof
sedimentusinginputdatain thefrequencyrange25-500 Hz. The one-dimensional,
horizontallystratifiedcase
is emphasized,althoughimplicationsfor problemsof higherdimensionalityare discussed.
Descriptionsof
theoreticalmethodsandexperimental
techniques
aswellasexamples
of inversions
of syntheticandexperimental data are presented.
Sl 10
J. Acoust.
Soc.Am.Suppl.1, Vol.82, Fall1987
114thMeeting:
Acoustical
Societyof America
$110
9:50
YY4.Bottominteraction
effects
onbroadband
signals.
PaulJ. Vidmata• (Science
Applications
lnternarional
Corporation,McLean,VA 22102)
Thispaperexamines
recentprogress
towardunderstanding
theeffectsof theseafloor
on low-frequency
broadband
signals.
First,themajorbottominteractionprocesses
atfeetinglow-frequency
signals
arereviewed
anda simplified(singlelayerfluid) geoacoustie
profileisshownto accurately
predicttheireffects.
A ray-based
approachfor simulating
singlebouncebroadband
signalsis thendiscussed.
The simulatorusesthesimplified
geoacoustic
profileto includetheseaflooraspart of thepropagationmedium.Underconditionsfor whichthe
simplifiedprofileaccuratelyrepresents
the acousticsof the seafloor,calculatedwaveformsagreewell with
acousticdata. Next, an approachfor simulatingmultibounce
signalsinteractingwith a layeredseaflooris
described
and usedto showthat layeringin the seaflooris the likely causeof somecharacteristics
of acoustic
datathatarenotpredictedbythesinglelayerprofile.Finally,thetimespreading
ofbroadbandsignalsin anarea
with about200 m of sedimentcoverisexamined.Acoustics
datahavebothsmall-scale( < 200 ms) andlargescale( > 1 s} timespreads.
Viewingthedatathroughseveralfrequency
bandsrevealsthat small-scale
time
spreads
areconcentrated
at highfrequencies
(consistent
with reflectionfor nearsurfacelayering)whilelargescaletimespreads
arecomposed
primarilyof lowfrequencies
(consistent
withinteractionwiththesubstrate).
A simplerayanalysis
showsthatthescattering
fromtheregionnearthepointof specularreflection
cannotbe
thesolecause
ofthelarge-scale
timespreading.
a•OnleavefromAppliedResearch
Laboratories,
TheUniversity of Texasat Austin,Austin,TX 78712.
ContributedPapers
10:,15
YYS. Stress-inducedanisotropy in sediment acoustics. R. D. Stoll
(Lamont-DohertyGeological
Observatory,
Palisades,
NY 10964}
A modelto describeseismicwavepropagation
in bothdry andwatersaturated
particulatematerialsisderivedonthebasisof theresponse
ofa
regulararrayof like elasticspheres.The theoriesof Hertz andMindlin are
usedto modelthenormalandtangentialcompliances
at theintergranular
contacts,andtheoverallresponse
of thearrayisfoundto begoverned
by a
setofnoalineardifferentialequations.
Theseequations
areintegratedover
a particularstresshistorythat simulatesthe normalbuildupandreliefof
geostaticstress(overburdenpressure
) in nature.Wavevelocitiesare evaluatedat variousstages
duringthisstresshistoryandtheresponse
isfound
tobeanisotropic
with respectto bothP andS wavevelocities.
In orderto
simulatethe response
of marinesediments,
theeffectsof watersaturation
are investigated
by usingthe compliances
calculatedfor the dry skeletal
framein conjunction
with the Biot theory.Finally, the predictions
of the
modelarecomparedwith recentlaboratoryexperiments
andfoundto be
in generalagreement.[Work supportedby ONR, Code 1125OA. ]
10:30
10:45
YY7. Quantitative experimentalverificationof seabedshear modulus
profile inversionsusingsurfacegravity (water) wave-inducedseabed
motions. Mark Trevorrow, Tokuo Yamamoto, Mohsen Badiey,
Altan Turgut,and Craig Conner(Divisionof AppliedMarine Physics,
Rosensriel School of Marine and Atmospheric Science, 4600
Rickenbacker
Causeway,Miami, FL 33149-1098)
A previously
developed
theoryenables
seabed
shearmodulusprofiles
to becalculatedthroughthecombination
of waterwave-seabed
interactiontheoriesandgeophysical
inversion
methods.
A newinstrumentation
system,consisting
of threeorthogonally
mountedaccelerometers
and a
pressure
sensor,
hasbeendeveloped
tomeasure
waterwave-induced
pressuresandseabed
motions.Thisnewpassive
remotesystemprovides
a fast
and convenient method to determine in situ sediment shear modulus with
depthprofiles,withoutdisturbing
thesediment
or drilling.Experiments
havebeenconductedin varioussediments
and waterdepthsoffthecoast
of New Jersey.Extensive
experimental
datareductiontechniques
aredeveloped
to dealwithrealoceandata.Actualexperimental
results
aregiven,alongwithquantitative
measures
of uncertainty
andresolution.
Comparisonsbetweenthe experimentalshearmodulusinversions,in situ
sediment
strengthtests,andlaboratoryanalysis
ofcoresamples
showthat
thismethodcanaccuratelypredictshearmodulusto depthsof 50 m or
more.[Work supported
by ONR. ]
YY6. Shallow seismoacousficexperiments using shear waves. R.
D. $toll, G. M. Bryan, R. Flood, D. Chayes, and P. ManIcy
(Lam0nt-Doherty GeologicalObservatory,Palisades,NY 10964)
Duringthe summerof 1986a seriesof seismoacoustic
experiments
werecarriedoutin shallowwaterofftheNewJersey
shore.Thepurpose
of
theseexperiments
wasto measurethegeoacoustic
propertiesof theocean
sedimentsthat comprisethe upperfew hundredmetersof the sediment
column.Scismiesourcesand receiversweredeployedat or verynearthe
bottom in order to excite shear waves in the sediment and minimize the
effectsof interferencefrom water-bornepropagation.The experiments
were performedat severalsiteswhere prior field work had established
physicalproperties
anda detailedprofileof thesediments.
By usingconventionalair gunsdeployedin an unconventional
way, stronginterface
and divingshearwaveswere generated,and thesedata were invertedto
obtainshearwavevelocityas a functionof depth.The inversionresults
11:00
YYg. Acousticwave propagationthroughporousmedia with arbitrary
pore-sizedistributions.
Tokuo YamamotoandAltan Turgut (Division
of Applied Marine Physics, Rosenstiel School of Marine and
AtmosphericScience,4600 RickenbackerCauseway,Miami, FL 33149}
In the Biot theory, the effectof frequencyon the oseillatoryviscous
forceswithin a porousmediumis treatedby replacingthe kinemarieviscosityv by an oscillatoryviscosityvF. Here, F is a functionof angular
frequency•o,the kinemarieviscosity•, and the singleporesizea. In this
paper,a mathematical
expression
of Fis presented
for arbitrarydistributionof poresizesthatcanbeusedin theBiottheorywithoutmodification.
It isshownthatporousmediawith a givenpermeabilityandporositymay
were then compared with the predictions of a geoacoustiemodel that
be representedby an infinite number of pore-sizedistributions. The dis-
accountsfor the effectsof voidsratio, overburdenpressure,and other
physical
parameters.
The in situmeasurements
fromexperiments
andthe
gradientspredictedby the modelwerein goodagreement,
suggesting
a
strongdependence
of velocityon overburdenpressurenear the watersedimentinterface.[Work supportedby ONR, Code 1125OA].
persionand attenuationof acousticwavesthroughsuchporousmediaare
independentof the pore-sizedistributionat the low- and high-frequency
limits,whiletheyare stronglydependent
on the pore-sizedistributionin
the intermediatefrequencyrange.For porousmediawith •-normal pore
sizedistributionshavinga givenvalueof permcability,the maximumspe-
$111
J. Acoust.Soc. Am. Suppl. 1, Vol. 82, Fall 1987
114th Meeting:AcousticalSocietyof America
S111
cificattenuationdecreases
and the bandwithof dispersion
increases
with
an increasingstandarddeviationof the pore-sizedistribution.Finally, the
generalized
Blot theoryfor arbitrarydistributionof poresizesis comparedwith the entiredata of compressional
waveattenuationthrough
surficialmarinesediments
givenby E. Hamilton.Comparison
betweenhis
data and the predictionsfrom thistheoryshowgoodagreement.[Work
supportedby ONR. ]
11:15
YY9. Effectsof seabedproperties
on acousticnormalmodepropagation
in a stratified shallowocean. Mohsen Badicy (Division of Applied
Marine Physics,RosensticlSchoolof Marine and AtmosphericScience,
thata simpleshearsourcein a layeredmediumdoesnot fullyexplainthe
observed
data.Syntheticsources
mimicthe experimentalsourceby combininga dipoleshear,a torque,and an explosionsource(in the water).
This complexsourceis appliedto differentvelocity/attenuation
models,
andresultsarecompared
to thedata.Thefrequency
bandofthesynthetics
is 2-15 Hz, matchingthepredominant
frequencies
of thedata;thephase
velocityrangeis0.05to 1.0km/s;all possible
modeswithinthesefrequency andphasevelocityrangesarecomputed.
Varyingthickness
andvelocity of a low-velocitylayerbothat the top andwithinthe sedimentsection
producestrikingchanges
in thecharacterof theseismograms.
Normal or
inversedispersion
characterize
the late-arrivingguided-wave
portionof
the synthetics.The early-arrivingdivingwavesgenerallydo not exhibit
appreciable
dispersion.[ Researchsupportedby ONR. ]
4600 RickenbackerCauseway,Miami, FL 33149)
Thepressure
fieldof a pointsource
in a shallowstratified
oceanovera
nonhomogeneous
anisotropic
seabedis calculatedusingnormalmodes.
Thesediment
ismodeledusingtheBiot-Yamamototheoryofporo-elastic
media.The influence
of geoacoustic
properties
of sediments
on low-fre-
quency
transmission
lossisinvestigated.
It isfoundthatthevariationof
permeability
haslargeinfluence
on acoustic
waveattenuation,
whereas
theelasticproperties
variationhaslesser
effect.Finally,theexisting
model
is usedin an attemptto extractthe depthstructureof permeability
and
porosityof theseabed.
[ Worksupported
by ONR. ]
11:30
YYI0. Syntheticmodelingof shearwavesin shallowmarinesediments.J.
A. Carter, G. H. Sutton, N. Barstow (Rondout Associates,
Incorporated,
P.O. Box224,StoneRidge,NY 12484),andJ. I. Ewing
(WoodsHole Oceanographic
Institution,WoodsHole, MA 02543)
Full-waveform
syntheticseismograms
arebeingusedto aidinversion
for shearvelocityand attenuationmeasuredin shallowmarinesediments
offthecoastof southernNew Jerseyin May 1986.Horizontallyandverti-
cally polarizedshearwaveswereproducedby a pair of air guns,fired
alternatelyleft andright,mountedona sled.Initial studiesdemonstrated
FRIDAY
MORNING,
20 NOVEMBER
11:45
YYI1. Dynamic behavior of sedimentand water-sedimentinterface.
Homogenizedprocessapplicationto poroussaturatedmedia.C. Avallet
(Metravib R.D.S., 64, ChemindesMouilles,69130 Ecully, France)
An applicationof the homogenized
processto thedynamicbehaviorof
marinesediments
ispresented
here.The mediumisconsidered
asa porous
viscoelastic
solidsaturatedby a viscousfluid. Underthe assumption
of
periodicityfor pore structure(microscopicscale), the homogenization
techniqueleadsto the macroscopic
description.The setof equationsso
obtainedissimilarto theclassical
Biot'sresults.The homogenized
model
is somewhateasierto use:A generalizedDarcy's law governsthe motion
of theporefluidrelativeto the solid[ Auriault et al., J. Acoust.Soc.Am.
77, 1641-1650 (1985)]. A reasonable
assumptionallowsthe computationof thefrequency
dependence
of thepermeability
fromits quasistatic
value.Using the homogenized
set of macroscopic
equations,compressionaland shearwavesin porousmedia,surfacewavesat fluid-porous
solid interface,and reflectionpropertiesof plane acousticwaveswere
calculated.Resultsarecomparedto thoseobtainedby Biot'stheoryand to
experiments.
The aim of this work wasto showthe applicabilityof the
modelto unconsolidated
sediments(high porositysilt andclayor sandy
media). [Work supportedby D.R.E.T.]
TUTTLE
1987
SOUTH ROOM, 9:00 TO 11:40 A.M.
SessionzZ. Noise VI: Measurement Techniquesand a Review of Noise Effects on Man
Julia D. Royster, Chairman
EnvironmentalNoiseConsultants,
Inc., P.O. Box 144, Cary, North Carolina27511
Chairman's
Introduction--9:00
ContributedPapers
9:05
ZZl. The influence of the center frequency of a narrow-band shortduration impulse noise on the growth of TTS. Chantal Laroche and
Raymond H•tu (Grouped'acoustiquedel'Universit•deMontr•al, C.P.
6128, Suet. A, Montr/-al, QuebecH3C 3J7, Canada)
The foilowingstudyhascontributedto theknowledgeof the effecton
humanhearingof thespectralcontentof impulsenoise,a parameterthat
hasbeenlittle studiedto date.In thisstudy,signalswerecomputergenerated to obtain I octaveband wide impulsesfrom a (sin x)/x numerical
Sl 12
J. Acoust.Soc.Am.Suppl.1, Vol. 82, Fall 1987
function.The centerfrequencywasvariedsoasto generatefour signals
centeredon 1, 2, 3, and 4 kHz. In this study, ITS growth curveswere
obtainedwith a targetasymptoticeffectof 8-12 dB after 30-45 min of
exposure
ata rateof 1pps.Therequired
levelofexposure
wasdetermined
to obtainthistargeteffect.To reachthesamelevelof ATS, theLOof the 1-
kHz signalhadto beat least5-7 dB higherthanthatof the2-kHzsignal.
For twoof foursubjects,
comparable
levelswererequiredfor the3- and4kHz signals
toobtainthepredetermined
effect,butthesewereat least5 dB
belowthecorresponding
levelforthe l-kHz signal.Theseresultsdemonstratethatthespectral
contentofimpulse
isa crucialfactorin thepredictionofthenoxiousness
of thistypeofnoise.[ Worksupported
by IRSST.]
114thMeeting:AcousticalSocietyof America
Sl 12
combined.
The procedure
for automatically
identifyingprominentdiscretetonesperANSI S12.10isdiscussed.
ZZ2. Digital processingof serosonic signals. W. C. Meetham,
E. Wildauer (Department of Mechanical,Aerospace,and Nuclear
Engineering,Universityof California,Los Angeles,CA 90024), and S.
A. Mclnerny (AerospaceCorporation,El Segundo,CA 90009)
9:50
ZZ4. Noise sourceidentificationon an IBM typewriter using sound
Experimentaldatawereobtainedfromtestsperformedin theNASAAmes7-X 10-ftwindtunnel.A digitizingprocess
for flowovera bluntedgedair foil wasusedto comparedatawithananalogsystem.
The nearfieldsurface-pressure
signalon the wing and the farfieldaerosonicsignal
werecross-correlated.
Digitalfilteringwasappliedto thedatato suppress
unwantedsignals.
The resultsof near-/farfieldcrosscorrelationsshow,
usingthedigitizedtreatment,thatthereissubstantial
ringing,a relatively
narrow-band
source.Analogprefiltering
exhibitsa shiftto lowerfrequency, dueto frequencyroll-offof the RC analogfilters.It is shownthat the
clip-correlation(neededfor analog) and the digitizedfull correlation
methodsgivesimilarresults.But the absolutevalueof the correlationis
lostin clipping.[Work supported
by NASA-Ames.]
intensitytechnique.
Li L ZengandMalcolmJ. Crocker(Departmentof
MechanicalEngineering,
AuburnUniversity,Auburn,AL 36849)
Noise source identification was carried out on an IBM ball element
electrictypewriter.Theselective
operationmethodwasusedtosurveythe
vibrationandsoundpressure
of differenttypewritersources.
The sound
powerradiationof differentnoisesources
wasmeasured
usingthe twomicrophone
soundintensitytechnique.
The measurements
showedthat
theimpulseradiationof theballelementstrikingtheplatenisthehighest
noise source,and the differencebetween the results with and without
paperis small.Severalindexesthat suppose
to qualifythe accuracy
of
soundpowermeasurements
usingthe soundintensitytechniquewill be
discussed.
[Work supportedby IBM, Austin,TX.]
10.'05
9'.35
ZZS. Determination
ofloudness
witha programmable
real-timeanalyzer.
M. Brechbuehiand Svein Arne Nordby (NorwegianElectronics-
ZZ3. Measuring the soundpower of a noisesourceand detectingpure
toneswith a singleinstrumentcombiningtrue 1/3 octaveband digital
Scantek,Inc., 51 Monroe Street,Suite i 603, Rockville,MD 20850)
filters and an FI• analyzer. Ole-Herman Bjor and Gustav Ese
(NorwegianElectronies-Scantek,
Inc., 51 Monroe Street,Suite 1603,
An efficientprogramfor determination
of loudness
as specified
by
Zwicker[E. PaulusandE. Zwicker,"Computer
programs
forcalculating
Rockville, MD 20850)
loudnessfrom i/3 o•tave band levelsor from critical band levels" (in
German), Acustica27, 253 (1972)] ismadetooperateona portablerealtimeanalyzer.The programcontrolsthemeasurement
andcalculates
the
loudness
asperISO R 532B.The usermayviewtheresultsgraphically
on
In thepast,therehasbeena requirement
for determination
ofboththe
soundpowerof sourcesand an investigationof the pure-tonecontent.
Thisisespecially
truein thecomputerandbusiness
equipmentindustry.
Measurementof the soundpowernormallycallsfor standard(ANSI)
classIII 1/3 octaveband filters,while pure-tonedeterminationrequires
narrow-b•d (FFT) measurements;
hence,two separateinstrumentsysternswererequired.This paperdescribes
a newinstrumentfor thesedeter-
the RTA's black and white monitor or in full color on an external monitor.
Thiscompletely
automaticsystem
operates
withouttheuseof anexternal
computerdue to the uniqueinternalBASICprogrammability
of the realtimeanalyzerused.The usermayeasilymodifytheprogramto meethis/
her ownrequirements
incorporating
EPNdB, Stevens
Loudness,
etc.
minations in which the true standardized !/3 oct filters and the FFT are
10:20-10:25
Break
10:25
ZZ6. E 'alnationof a hearingconservationprugramat a large industrial
company.
WilliamW. Clark,CarlD. Bohl,LisaS. Davidson,andKeith
A. Melda (Central Institute for the Deaf, 818 S. Euclid, Saint Louis,MO
63110)
The hearingconservation
program(HCP) of a largeindustrialenmpanywasevaluated
by comparing
theaudiometric
dataof twogroupsof
workersfromthreegeographically
separate
plants.Group 1 wasselected
from individualsemployedin areaswhere the time-weightedaverage
(TWA} soundlevelexceeded
90 dBA andgroup2 fromindividualswith
TWAs
of less than 85 dBA. Differences between mean STS values for
groupsandplantswerethemaincriteriausedin makingjudgments
onthe
HCP effectiveness.
in addition,age,sex,yearsof service,andnonoccupational noiseexposurewereevaluated.A significant
differencein mean
STSwasfoundbetweenthetwo groups;however,the"nonoccupationally
exposed"
grouphadmoreSTSthanexpected.
The male-femaledistribution,previous
hearingloss,andnonoccupational
exposure
werejudgedto
becontributing
factorsin thedifferences
that existedbetweenplantsand
groups.[ Worksupported
by GrantOH 02128from NIOSH. ]
The sensitivity
of predictedgroundnoiselevelsfor advancedturbopropaimrafttochanges
inatmospheric
absorption
losses
isreviewed,
and
theresultingcommunitynoiseenvironments
evaluatedin termsof possiblecriteriafor acceptable
levels.Atmospheric
absorption
coefficients
at
highaltitudesare subjectto possible
errorsof over + 70% due to the
currentuncertaintyin atmospheric
absorptionpredictionmodelsat the
very low humiditiesinvolved.However,the integratedabsorptionloss
over the entirepropagationpath is nearlyindependent
of the particular
predictionmodelchosen.
The humidityandtemperature
structureof the
atmosphereis a more significantsourceof variationin the total atmosphericabsorptionloss.Basedon a referenceprofileof humiditycontent
versusaltitude,andexistingmodelsfor a standardatmosphere,
estimates
of enroutenoiseof advancedturbopropaircraftare madeandcompared
with availabledata. The noiseexposureon the groundis considen:din
termsof boththe maximumsoundlevelandsoundexposure
levelfor one
overflight,and theday-nightaveragesoundlevelfor variousscenarios
of
dailyoperations.
Theseestimates
of the resultingcommunitynoiseexposureare comparedto possible
criteriafor acceptable
levelsfor singleand
multipleaircraftflyovers.[This work wassupportedin part by the Federal Aviation Administration.]
10:55
10:40
ZZ7. Soundpropagationand communitynoise exposureconsiderations
for enroute noise of advancedturboprop aircraft. John Weslet (Wylc
Laboratories,2001 JeffersonDavis Highway, Suite 701, Arlington, VA
22202) and Louis C. Sutherland (Wylc Laboratories,128 Maryland
Street,El Segundo,CA 90245)
Sl 13
J.Acoust.
Soc.Am.Suppl.1,Vol.82,Fall1987
ZZS. A theoretical interpretation of a dosage-effectrelationshil•for the
prevalence of annoyance in a community. Sanford Fidell, David
M. Green, and Theodore Schultz (BBN Laboratories Incorporated,
P.O. Box 633, CanogaPark, CA 91304-0633)
A dosage-effect
relationship
by Schultz["Synthesis
of socialsurveys
on noiseannoyance,"J. Acoust.Soc.Am. 64, 377•,05 (1978)], that
114thMeeting:
Acoustical
Society
ofAmerica
Sl 13
relatescommunitynoiseexposureto the prevalence
of annoyance,
has
becomea widely usedtool in assessing
environmentalnoiseeffects.BecauseSchultz's
relationship
isappliedtoa broadrangeofexposure
conditions,andbecause
it isentirelyempirical,itsapplicationto specificsituationsisfrequentlychallenged.
A simplemathematical
modelcanaccount
notonlyfor theshapeof therelationship
synthesized
by Schultz,but also
for the differences
betweenSchultz'srelationshipand that proposedby
Kryter ["Community annoyancefrom aircraft and ground vehicle
noise,"J. Acoust.Soc.Am. 72, 1222-1242(1982)]. A singleparameter,
representing
response
bias,suffices
for thispurpose.[Thisworkwassponsoredby the U.S. Air ForceNoiseand SonicBoomImpactTechnology
programunderContractF33615-86-C-0530.
]
10 000 Hz in stepsof 1/3 octave.Plotswereobtainedin the horizontal
planefor threeconditions:( 1) earopen;(2) earoccludedwith a malleablefoam-typeear plug;and (3) earcoveredby a conventional
earmuff.
Polardatawereconverted
to field-to-drum
transferfunctionsfor every
45' changein angleof signalincidencefor eachcondition.The diffuse-
fieldear-open
transfer
functions
willbecompared
topreviously
published
functions
forKEMAR. Theeffects
ofearocclusion
withmuffs,caps,and
plugsas seenby attenuationand canalresonanceshift will be discussed.
11:25
ZZI0. A theoretical model of the annoyanceof individual noise
intrusions. Sanford Fidell, David M. Green, and Karl S. Pearsons
(BBN Laboratories,
Inc., P.O. Box633,CanogaPark,CA 91303)
11:10
ZZ9. Effects of hearingprotectorson headdiffraction.JohnR. Franks
(Bioacoustics
and OccupationalVibration Section,PhysicalAgents
EffectsBranch,Division of Biomedicaland BehavioralScience,National
Institutefor OccupationalSafetyand Health, 4676 ColumbiaParkway,
Cincinnati, OH 45226)
The diffractionby theheadandpinnaof soundincidentupontheear
hasbeenwell documented.However, the modificationof headdiffraction
patternsby the placement
of hearingprotectors
in, or over,theearshas
notbeeninvestigated.
Polarsensitivityplotswereobtainedin an anechoic
soundfieldfromtherightearof theKnowlesElectronics
Mannequinfor
Acoustic Research(KEMAR). Test frequenciesranged from 100-
FRIDAY
MORNING,
20 NOVEMBER
1987
Self-reports
of noise-induced
annoyance
canbe modeledastheproductofa rational,decisionlike
process
in whichpeople
discriminate
among
annoyingand nonannoying
noiseintrusionsheardin the presence
of a
reference
distribution
of noiseexposure.
Thisview,developed
underthe
sponsorship
of the U.S.Air ForceNoiseandSonicBoomImpactTechnologyprogram,canassignexplicitrolesto bothacousticandnonacoustic variablesin a probabilisticdecision-making
process.The model,expressible
in spreadsheet
form,permitsidentification
of twocomponents
of
annoyance
judgments:
directannoyance,
basedonsensitivity
totheimmediatecharacteristics
ofacoustic
signals,
andresponse
bias.Themodelalso
providesinsightintotheextentto whichacousticvariablesmaybeconsidered to causeannoyance.
UM AUDITORIUM,
9:00 A.M. TO 12:00 NOON
SessionAAA. SpeechCommunicationVII: CrossLanguageStudiesof Production
GeorgeD. Allen, Chairman
Department
of •4udiology
andSpeech
Sciences,
PurdueUniversity,
WestLafayette,Indiana47907
ContributedPapers
AAA!. The coordinationof glottal with oral articulafiohs in Icelandic and
Hindi.$ohn Kingston(DMLL, MorrillHall, CornellUniversity,Ithaca,
NY 14853-4701)
In mostconsonants
producedwith glottalabduction,the openingis
largelyor entirelycontainedwithintheaccompanying
oral articulation.
Furthermore,
thepeakglottalopening
occursat a constant
intervalfrom
the beginningof the oral articulationin unaspiratedstopsand voiceless
fricativesand at a constantintervalfrom the releasein aspiratedstops,
indicatingtightcoordination
with theoral articulation[A. I_fifqvistand
H. Yoshioka,"lnterarticulator programmingin obstruentproduction,"
Phonetica
3g,21-34 ( 1981) 1.IcelandicandHindipossess
stopsin which
the glottal openingtakesplacelargely outsidethe oral closure;in Icelan-
dic presspiratedstops,abductionprecedesthe closureand in Hindi
breathyvoicedstops,abductionfollowsthe closure.Both languages
also
have(post) aspiratedstopswith whichthe stopsof interestcanbe compared.Thisstudyexamined
whetherexternalglottalarticulations
arealso
vary with the precedingstop closure.In Hindi, the duration of both
breathyvoiceand (post) aspirationcoratied with the durationof the
preceding
stopclosurebutthedurationof neithercovariedwiththatof the
followingvowel.BothkindsofHindistopsarelikethoseobserved
in other
languages,
but the relativetimingof glottalandoral articulations
in the
Icelandicstopsis dearly different.In that language,the oral articulation
with whichthe glottalarticulationiscoordinatedisthe vowelor the vowel
and consonant combined.
9:15
AAA2. Temporal effectsof geminateconsonantsand consonantclusters.
MargaretH. Dunn (Yale Universityand HaskinsLaboratories,
270
Crown Street, New Haven, •F 06511 )
Current phonologicaltheory analyzesgeminateconsonantsas
quences
ofadjacenttimingslotsthatcompletely
sharefeatures
whileclosingonesyllableandopeningthenext.Thisanalysis
predictsthatthetem-
tightlycoordinated
with theoral articulation
of the consonant.
Onefe-
poralorganization
of utterances
withgeminate
consonants
isparallelto
malespeakerof eachlanguagehasbeenrecordedsofar, producingwords
containingthe stopsof interestat differentratesand with stresseitheron
thesyllablecontaining
thestopor not.If theoralandglottalarticulations
are coordinatedwith one another,then changesin their individualdurationsdueto changes
in rateor stresslocationshouldcoysty.The duration
of bothpre-andpost-aspiration
in Icelandiccovariedwith thedurationof
the adjacentvowel,and the durationof preaspiration
alsocovariedwith
the followingstopclosure,but the durationof postaspiration
did not co-
that of utterances
includingheterosyllabic
consonant
clusters.This predictionwas testedusingFinnishand Italian, two languageswith very
differenttemporalorganizations.
Five Italian andfour Finnishsubjects
S114
J. Acoust.
Soc.Am.Suppl.1, VoL82, Fall1987
readlistsof nonsense
wordsincludingbilabialgeminatcsandbothhomor-
ganicandheterorganic
clusters.
The hypothesized
equivalence
of geminatesand clusterswastestedby examiningthe amountof closedsyllable
vowelshortening
exhibitedin thetwoenvironments.
The resultsdid show
that geminatespatternedwith dusters,with respectto precedingvowel
114thMeeting:
Acoustical
Societyof America
S114
durationin bothlanguages,
butclosed
syllablevowelshortening
wasexhibitedonlyin theItalian.This •sult suggests
that the syllablemaybe
usedasa unitof temporalorganization
in Italian,butsomeotherunitsof
temporalorganization
mustbe proposed
for Finnish.[Work supported
by NIH Grant NS-13617.]
casualspeaking
styles.The paperis particularlyconcerned
with output
constraints
that canbe understood
in termsof systems
of phonemiccontrast.Specifically,
it ispredicted
thatwhenthephoneroes
ofa language
are
widelyspreadout in the acousticspace,then the acousticoutputconstraintson them are lessstringentthan if the phoneroes
werecrowded
together.Data supportingthis view will be presentedfor vowel-to-vowel
coarticulation
in threeBantulanguages.[Work supportedby NIH to
9:30
HaskinsLaboratoriesand NIH to M. I. T. ]
AAA3. VOT variability in stop-consonantproductions by bilingual
speakersof Englishand Mandarin Chinese,Judith L. Lauter and Fang
Ling Lu (Departmentof SpeechandHearingSciences,
Universityof
10:15
Arizona, Tucson,AZ 85721)
It hasbeenobserved[e.g.,L. Williams,Percept.Psychophys.
21,289297 (1977) ] that somebilingualspeakersof Spanishand Englishwill use
language-appropriate
VOT valuesin elicitedsetsof Englishand Spanish
stops.As partof an ongoingcross-language
projectin repeated-measures
acousticphonetics,
six nativespeakers
of MandarinChinese(three femalesandthreemales)wereaskedto producerepetitions
of Englishand
Chinesestopsin a nonsense/ha-'Ca/context.
For theChinesestops,five
separateserieswerecollected,with the stressed
syllablepronouncedon
eachof fiveChine• tones.Productions
weredigitizedviapulsecodemoduiator,storedon videotape,and VOT segments
identifiedand measured
usingwaveformanalysissoftwaredeveloped
in our laboratory.Measurementsof meanVOTs for eachtalkerindicatethat Englishand Mandarin
Chineseare similarin rangeof absoluteVOT values,clearVOT distinctionsbetweenvoiced/voiceless
stops,and inconsistent
useof VOT to distinguishplaceof articulation.Further,VOT oariabilitypatternssuggest
that for someof thesetalkers,controlof VOT timing may be sensitiveto
tonalcontext,and thissensitivitymay be reflectedin productionsof Englishaswell asChinesestops.[Work supportedby AFOSR.]
9:4•
AAA6. Supportfor the frame modelin Turkish and in English.Suzanne
E. Boyee(HaskinsLaboratories,
New Haven,CT 06510)
The look-ahead
and the framemodelof anticipatorycoarticulation
makedifferentpredictions
aboutlip movementin a wordsuchas/ustu/.
The look-aheadmodelpredictsthat roundingfromthesecondvowelwill
spreadinto the intervocalicconsonants,
producinga singlemovement
with a long sustainedphase;the frame modelpredictstwo distinctgesturesfor theroundedvowelswhosetailsmayoverlapsomewhat,
producingtwopeakswitha "trough"between.
In earlierwork,it wasshownthat
for nonsense•vords, such as /kuktluk/, English speakersproduce
troughs,while Turkish speakersshow plateaulikepatterns.Does this
meanthatTurkishandEnglishspeakers
employ,respectively,
look-ahead
and framestrategies
for eoarticulalion?
Alternatively,the framemodel
holdsfor Turkish, but Turkish roundinggesturesare larger and longer,
overlappingfor a greaterproportionof their tails.An additivemodelof
overlapcouldthen producea plateaulikepattern.Speakers'movement
tracesfrom/kiktlik/and/kuktluk/were addedandthe resultcompared
with thosefor/kuktluk/; a goodfit for Turkish speakerswastakenas
evidencefor theframemodel.Further,theproportionof roundingduring
the consonantintervalwas differentfor the two languages.Both tests
supporttheframemodal.[ Worksupported
by NIH. ]
AAA4. Stop consonant voicing in Malay-English bilinguals. Grace
H. Yeni-Komshianand Inderjit K. Bhathal (Departmentof Hearing
andSpeechSciences,
Universityof Maryland,CollegePark, MD 20742}
The productions
of two groupsof Malay-Englishbilingualswereinvestigated.
The subjects,
nativespeakers
of Malay, wereaskedto read
Malay and Englishwordsthat differedin voicingof initialand finalstop
consonants.
Thefoursubjects
in theMalaysia
groupresided
in Malaysh
andwerenotexposed
to a predominantly
Englishspeaking
environment,
and the two subjectsin the U.S. groupresidedin the U.S. for 5 years.
Resultson word initial stopsare reportedhere.In Malay, voicedinitial
stopsarecharacterized
by voicingleadandvoiceless
stopsby shortvoicing lag.Comparison
of the twobilingualgroupsrevealedthat, although
therewerenosignificant
differences
in thevoicedproductions,
therewasa
shifttowardsa moreEnglishlikeproductionfor the voiceless
stopsby the
U.S. group.Analysisof the Englishwordsshowedno differences
in the
productionof the voicedstops;however,the U.S. groupproducedthe
voiceless
stopswith significantly
longerrOT valuesthan the Malaysic
group.Noneof the subjects
showeda shiftin voicingcharacteristics
asa
functionoflanguage.
Theseresultssuggest
thatnativeMalayproductions
in bilinguals,residingin theU.S., werealteredin a directionthat ischaracteristicofEnglish.
10:30
AAA7. Quantitativecharaeterizationof degreeof coarticulationin CV
tokens.Abigail C. Cohn (Departmentof Linguistics,Universityof
California,Los Angeles,CA 90024-1543)
Languages
areoftenassumed
to showgreateror lesserdegrees
ofcoar-
ticulation[ P. Ladefoged,
in Papers
in Linguistics
andPhonetics
in MemoryofPierreDelattre,editedbyA. Waldman(Mouton,TheHague,1972),
pp.273-286], yetnoquantitative
measure
existsforcharacterizing
degree
of coarticulation.
In thisstudy,thedevelopment
of a metricfor degreeof
influenceof a vowelon a precedingstopconsonant
hasbeenundertaken.
For eachlanguage
in thestudy,LPC spectraweremadeat theburstonset
of initialstopsfollowedbya vowel.Templates
weremadeof thesespectra
whenthe vowelwas/a/. The stopspectrawith othervowelsweretested
againstthesetemplatesto determinea percentfit. Languages
differin
theirpercentfit;a lowpercenttit indicates
that vowelshavea greateffect
onpreceding
consonants
anda highpercentfit indicates
thattheydonot.
Kana,a language
of Nigeriawhichgivestheauditoryimpression
of havinga highdegreeof coarticulation,
is beingcompared
to otherlanguages
includingRussian,a language
with secondary
articulations.
[Work supportedby NSF.]
10.'00
AAA•. Output enna•raints and cross-languagedifferences in
coarticulation. Sharon Y. Manuel (Bldg. 36-529, Massachusetts
Instituteof Technology,
Cambridge,
MA 02139)
Coarticulatory
patternshavebeenshownto varyfromlanguage
to
language,
fromspeaker
tospeaker,
andfromonestyleor rateof speaking
tothenext.Manyofthese
differences
mightbeexplained
byassuming
( 1]
thatphones
areassociated
withranges
of acceptability,
thatis,"acoustic
outputconstraints,"
whichmust not be violatedby coarticulation-indueedvariabilityand (2) that theseoutputconstraints
vary from languageto language,
speakerto speaker,etc. For thisnotionto haveany
predictioe
value,it is necessary,
in turn, to be ableto predict,to some
extent,
justwhattheacoustic
outputconstraints
are,andhowtheymight
vary.It mightbeexpected,
for example,thatoutputconstraints
relaxin
S115
,l.Acoust.
Soc.Am.Suppl.
1.VoL82.Fall1987
10:4•
AAAg. Timing of contextualnasalizationin two languages.Marie
K. Huffman (Departmentof Linguistics,Universityof California,Los
Angeles,CA 90024-i 543)
Coarticulatory
patternsin nasalityin twoWestAfricanlanguages--AkanandEfik will bedescribed.
Theselanguages
makedifferentphoriologicaluseof the feature{nasal). Nasalityisdeterminedfrom nasaland
oralairflowasrecorded
witha Rothenburg
splitmask.Thefacusisonthe
timingof contextual
nasalization;
in particular,thecoarticulatory
effects
of nasalconsonants
onadjacentvowelsthatarenotcontrastively
( q- nasal}.Theseeffects
aresaidto varydepending
on thephonologieal
useof
nasalityin a language.In Akan, thereisan oral/nasalcontrastonvowels,
114thMeeting:
Acoustical
Society
ofAmerica $115
evenin theenvironment
of nasalconsonants;
thuscontextualnasalization
ized like the lax vowelsin Germaniclanguages,
but couldstill be de-
maybelimited,soasto preserve
thephonemic
contrast.
In Efik,thereis
scribed with a feature lax.
no suchcontraston vowels,socontextualnasalizationof vowelsmay be
moreextensive,
beginning
earlier,andendinglater,ashasbeenreported
elsewhere
forEnglish.
Dataforseveral
speakers
ofeachlanguage
willbe
11:30
discussed.
[Work supported
by NSF.]
AAAII.
Cross language study of the effects of voiced/voiceless
consonants
on the vowelvoicesourcecharacteristics.
AilbheNi
Chasaideand Christer Gobl (Centrefor LanguageandCommunication
Studies,
TrinityCollege,
Dublin2, •.ireandDepartment
of Speech
11:oo
AAA9. Cross-linguisticarticulatory models of vowels. Michel T.
T. Jackson (Phonetics Laboratory, Department of Linguistics,
Universityof California,LosAngeles,CA 90024-1543)
Themathematical
andphoneticfoundations
of a familyof techniques
for quantitatively
analyzingarticulatorpositions
duringspeechproduction will be discussed
in termsof a smallnumberof modesthat spanthe
observed
spaceof articulatoryvariation.Particulararticulatorypositions
arerepresented
asweighted
combinations
of themodes;
variousnaturalhessconditions
that dependon havingmultispeaker
datacanbeusedto
resolve mathematical indeterminacies in the choice of modes. Results us-
ingmeasurement
of articulatorpositions
fromsagittalx raysof English,
Icelandic,Spanish,
andAkanvowelssuggest
thatthebasisneededfor any
onelanguage
isof relativelysmalldimensionality.
Typically,onlytwo or
threemodessuffice
to generate
theobserved
rangeofarticulatorpositions.
However,not all languages
havethesamemodesof articulatorpositioning.Thusa cross-language
modalanalysis
requires
higherdimensionality,
i.e., moremodes.In conclusion,thereare systematicdifferences
between
languages
in thefunctionalorganization
of a setof articulatoryprimes.
Thesedifferences
in functionalorganization
!endto the observed
crosslanguage
differences
in modalorganization.
[Worksupported
by NSF.]
Communication and Music Acoustics, KTH, Box 70014, S-100 44
Stockholm, Sweden)
Sourcecharacteristics
of a vowelmaydifferaccordingto the voiced/
voiceless
natureofadjacentconsonants.
Thepostvocalie
consonant
could
beparticularly
crucial,asvocalfoldabduction
for a voiceless
consonant
maybeinitiatedconsiderably
beforeoralocculsion.
Here,CV (:) C utterances(whereC = voiced/voiceless
labialstopor fricative)wereanalyzed
forfemaleandmalespeakers
ofSwedish,
English,andFrench.Characteristicsof the voicesourceweremeasuredfrom inversefiltereddata using
thefour-parameter
LF modeldeveloped
at theKTH. Airflowrecordings
witha Rothenberg
maskallowedinferences
regarding
incomplete
vocal
foldclosureduringthe vowelandat onsetandoffsets.
Resultsindicate
majoreffects
ofa following
consonant;
thelaterpartof thevowelprecedinga voiceless
consonant
shows
a markeddropinexcitation
strength
and
a steeper
spectral
slope,asmightbeexpected
whenthevocalfoldsare
opening
butvibrating.
A spectral
consequence
ofthisabducting
gesture
is
a widening
of theF 1bandwidth
andan upwardshiftin formantfrequencies. These effectswere much less in evidence in French than in Swedish
andEnglish.
Thepreceding
consonant
hadcomparatively
littleeffect;
full
excitationstrengthis achievedalmostimmediately.
11:45
11:15
AAAI0.
Acoustic correlates of TENSE-LAX
vowels and ATR vowels.
AAAI2. An investigationof tag intonation in English. Richard
W. SproatandShirleyA. Steele(AT&T BellLaboratories,
2D-443,600
Mona Lindau-Webb (PhoneticsLaboratory, University of California,
LosAngeles,CA 90024-1543)
Mountain Avenue,Murray Hill, NJ 07974)
Germanicvowelsystems
typicallyincludetwo setsof vowels,a long,
tensesetanda short,lax set.Formantchartsof English,German,Dutch,
and Swedishshowthat lax high and mid vowelstend to have a more
centralizedpositionthantheir tensecounterparts.Tenseandlax low vowels do not showany suchsystematicrelationships
in the differentlanguages.
In Africanlanguages
with vowelharmony,theharmonizing
sets
aresometimes
labeledtense-lax,althougha moreappropriatelabelis advanced-retractedtongueroot (ATR). Formant chartsof Akan, DhoLuo, and Agwagwune(a Nigerianlanguage)werecomparedto the Germanicones.The tense-laxand + / - ATR featuresbehaveverysimilarly
"'Are youcoming?'hesaid,"where"he said"isan attributivetag,and"I
Tagsfrequentlyoccurin Englishtext. Commonexamples
include
boughta newcar,Manny,"where"Manny"isa vocativc
tag.Beenuse
of
thefrequency
of tags,it is importantto havean adequate
treatmentof
theirintonationfor morenaturalsoundingtext-to-speech
synthesis.
This
paperexamines
theintonational
properties
of tagsin AmericanEnglish
and discusses
their phonological
characterization.
Investigatedinstrumentallyare the F0 patternsemployedby speakers
producingtagsin
question
andstatement
contexts("'Are youhungry?'
hesaid"versus
"'I
amhungry,'hesaid").A phonological
analysis
isproposed
forsuchtags
buildingon workby Pierrehumbert
["Thephonology
andphonetics
of
for front vowels.Back - ATR vowels,however,tend to havea lower F2
than their + ATR counterparts,makingthemmoreperipheral,not more
Englishintonation,"Ph.D. dissertation,
MIT (1980) ] andBeckmanand
Pierrehumbert
["Intonationalstructurein Japanese
andEnglish,"Pho-
centre] like back lax vowels. Thus tense and ATR are not the same acous-
nologyYearbook
3, 255-309(1986)]. Finallytheincorporation
of these
tically. Althoughthesetwo featuresdo not occurcontrastivelyin any
language,theydo possibly
bothoccurin ruleswithina language.Agwagwunehascentralizedallophones
in closedsyllables.
Thesearenotcentral-
resultsintothetext-to-speech
systemunderdevelopment
at BellLaboratoriesisdiscussed,
andtheresulting
improvement
in thequalityofsynthe-
$116
J.Acoust.
Soc.Am.Suppl.
1,Vol.82,Fall1987
sis is demonstrated.
114thMeeting:
Acoustical
Society
ofAmerica
$116
FRIDAY AFTERNOON,20 NOVEMBER1987 UNIVERSITY LECTUREHALL, 1:30TO 4:30P.M.
Session
BBB.Psychological
andPhysiological
Acoustics
IX: Physiological
Acoustics
•zcan•zdamar,Chairman
Department
of Biomedical
Engineering,
Unioersity
of Miami, CoralGables,
Florida33124
ContributedPapers
1:30
BBB1. Phuse-lockof spontaneousoto-acousticemissionsto a cubic
difference
tone.Pim vanDijk andHeroP. Wit (InstituteofAudiology,
P.O. Box30.001,9700RB Groningen,The Netherlands)
at 0.5 kHz, 95 dBSPL,eachfor9 days.ThisSOAE,notpresentbeforethe
secondexposure,wasa narrow-bandsignalat 2.2 kHz that variedfrom
10-26 dB SPL acrossrecordingsessions.
The SOAE hasremainedstable
overthe3-yearperiodsinceit wasdiscovered.
Duringthepastyear,this
signal.
Therefore,
twotoneswithfrequenciesf•
andf2 andlevels
L• and
animalhasbeentrainedbehaviorallysothat detectionanddiscrimination
thresholds
canbe determinedin the regionnearthe SOAE. Measuresof
auditorysensitivityat quarter-octave
intervalsbetween0.125 and 16.0
kHz revealeda hearingloss(re: normalchinchilla)of 22 dB centeredat
werepresented
to earshavinga spontaneous
oto-acoustic
emission.
Here,
2.37 kH2. However, thresholdsdetermined at 10-Hz intervals between
f• andf2 produced
a 2f• --f2 distortionproductcloseto ( < 50 Hz) the
emission
frequency
fo. Frequency
spectraandzero-crossing
time trend
recordings
wereobtained
forvariousvalues
ofϥ,L2,fl, andf2. Whenthe
L• andL• weresufficiently
high,the emission
wasphaselockedto the
2f• -f• tonegenerated
in theear.WhenL, andL 2weresmall,theemissionwas:mstained
atfo. At intermediate
levels,the emission
is not constantly1o:kedto 2f• -f•, butoccasionally
jumpstofo.Thebehaviorde.-
1600Hz and2800 Hz showedthat the SOAE wascorrelatedgenerally
with a regionof enhancedsensitivityin the microstructure
of the audiogram. However,in the immediatevicinityof the SOAE thresholdswere
elevatedby 5-10 dB;additionof a tonalmasker(2.2 kH2 at 5-20 dB SPL)
If a singleexternaltoneisusedto studyphase-lock
of a spontaneous
oto-aeoustie
emission,
it isdifficulttoseparate
thistonefromtheemission
scribed above is identical to that of a self-sustainedoscillator in the,
presence
ofnoise,
drivenbyanexternal
tone[R. L. Stratonovich,
Topics
in the Theoryof RandomNoise(GordonandBreach,New York, 1963),
Vol. II, Chap.9]. [Work supported
by Z. W. O.]
hadnoeffecton theshapeof theaudiogram.
[Worksupported
by Grant
OH 02128 from NIOSH. ]
2:15
BBB4. Interaural phase and level effects on binaural interaction
component (BIC) of the brain-stem auditory evoked potential.
BallachandaB. Bopannaand GeorgeMoushegian(Callier Center
UTD, 1966 Inwood Road, Dallas, TX 75235)
1:45
BBB2. Effectsof frequencyseparationof primary toneson the amplitude
of acousticdistortion products.Frances P. Harris (Department of
Speech
andHearingSciences,
UniversityofArizona,Tucson,AZ 85721),
BardenB. Stagnet,Glen K. Martin, and Brenda L. Lonsbury-Martin
(Department of Otorhinolaryngologyand CommunicativeSciences,
BaylorCollegeof Medicine,Houston,TX 77030)
The effectsof frequency
separation
of equilevelprimarytones,
f• and
f> on theamplitudeof distortion-product
emissions
(DPEs) at 2f• -f2
wasinvestigated
in 10earsoffivehumanswithnormalhearing.TheDPEs
at 1,2.5,and4 kHz in response
to primariesat 65, 75, and85dB SPL were:
generatedwithf•/ft ratiosvaryingin 0.02 stepsfrom 1.01to either 1.41 (4
kHz), 1.5'9(2.5 kHz), or 1.79( 1kHz). Resultsindicatedthat, in generat..
ingthemaximumDPE amplitude,
fe -f• frequency
separation
wassys..
tcmatieallyrelatedto stimulusfrequencyandlevel.Thus,for all levelsof
stimulation,
f•/f• ratio wasinverselyrelatedto DPE frequencyso that
higherratiosweremosteffectivein generatingDPEs at I kHz, while
lower ratioselicitedlargeemissions
at 2.5 and 4 kHz. In addition,for all
three DPiEs,in obtainingmaximumresponses,
primary-tonelevel was
directlyrelatedtof•/ft ratio in that lowerratioswere mostefficacious
in
generatingDPEs to 65-dB stimuli,while higherratioselicitedlarger
DPEs in response
to 75- and 85-dBprimaries.On the average,however,.
across
all frequency-amplitude
stimulus
conditions,
maximalDPE ampli-.
tudewashestobtainedusinganf:/f• ratio of 1.23.Overall,DPE findings
describing
the outcomeof varyinglevel,frequencyseparation,
and fre-.
quencyregionof primarytoneswereconsistent
with thosereportedin the
psyehophysieal
literaturefor normal-hearing
humans.[Work supported
by NINCDS. ]
2:00
Electrophysiological
studieshaveelegantlydemonstrated
that neuronsin lowerbrain-stem
nucleiareexquisitely
sensitive
to theparameters
of soundthat mediatelocalizationandlateralization
phenomena.
In the
presentstudy,thebinauralinteractioncomponent(BIC), derivedfrom
brain-stem
auditoryevoked
potentials,
wasobtained
usinglow-frequency
stimuli with various combinations of time and level differencesdelivered
throughearphones.
Theaimhasbeentodetermine
whetherthesevolumeconducted
multineuronal
responses
revealanyofthe neuralmechanisms
of lateralization.
The findingsshowthat characteristics
of the binaural
interaction
component,
e.g.,latency,amplitude,
andwaveform
morphology,evokedby low-frequency
tonebursts,aredifferentially
alteredwith
changes
in interauralphase.The effectson thebinauralinteractioncomponentwith interauralleveldifferences
werealsosubstantialbut not similar to thechanges
producedwith phase.From thisresearch,
it hasbecome
apparentthat,givenappropriate
recording
andstimulating
parameters,
manynuances
ofbinauralhearingmaybeneurophysiologically
addressed
in studiesof volume-conducted
evokedandderivedpotentials.
2:30
BBBS. AP and ABR tuningcurves:A comparativestudy.Abdclhamid
A. Elshintinawy and Paul J. Abbas (The University of Iowa,
Departmentof SpeechPathologyand Audiology,Wendell Johnson
Speechand HearingCenter,Iowa City, IA 52242)
Whole-nerve
actionpotential(AP) andauditorybrain-stem
response
(ABR) wererecordedfrom anesthetized
eats.Response
amplitudeand
latencyto a probestimulusweremeasured
andtuningcurveswereconstructedusingthreemaskingparadigms;
forward,simultaneous
(a tone
burst maskeroverlappingthe probe), and continuous(a continuous
maskertone). AP andABR tuningcurvesweregeneratedon thebasisof
criterion changesin both amplitude and latency of the response.Within
BBB3. Spontaneous
oto-acousti½
emissionfroma chinchillaear following
exposureto noise.William W. Clark and Martha Solomonson(Central
Instituteibr theDeaf, 818 S. Euclid,SaintLouis,MO 63110)
eachof themaskingtechniques,
tuningcurvesdeveloped
fromtheampli-
A spontaneous
oto-acousticemission(SOAE) was observedin one
chinchillaaftertwoexposures
to anoctavebandof noise(OBN) centered
significantdifferences.
The only significantdifferences
were measured
acrossmaskingconditions.
Forwardmaskingtuningcurveswerefoundto
havesteeperhigh-fre•quency
slopes,
higherQ 10values,andlowersensitiv-
Sl 17
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
tude and latencycriterion changesof the AP and the ABR showedno
114thMeeting:Acoustical
Societyof America
$117
ity indicies(definedasthe difference
betweenprobeleveland the levelat
the tip of the tuningcurve). Low-frequency
slopesandthe tip-to-tailratiosshowedno significantdifferences.
[Work supportedpartiallyby the
DeafnessResearchFoundation.]
3:30
BBI]9. Evalust'onof aneight-channelscalatympanielectrodewith single
unit recordingin the auditory nerve. David. H. Liang (AEL 128.
Departmentof ElectricalEngineering,
StanfordUniversity,Stanford,CA
94305)
2:45
•zcan •zdamar, RafaelE. Delgado(Department
of Biomedical
In orderfor a multichannelcochlearprosthesis
to be moreeffective
thana single-channel
prosthesis,
thedifferentchannels
of thestimulating
electrode
mustbeableto activateseparatepopulations
of theneuronsin
Engineering,Universityof Miami, Coral Gables, FL 33124), and
Ferdinando Grandori (Polytechnicof Milan, Milan, Italy)
the auditory nerve. Earlier animal studies[C. van den Honert and P.
Stypulkowski,
Hear. Res.14, 225-243 ( 1984);H. S. Lusted,Ph.D. thesis,
BBB6. Fiber tract model of auditory brain-stem responsegeneration.
A fiber tract model for the generationof auditory hrain-stemresponses
(ABRs) is developedusingvolumeconductedpotentialsin a
sphericalconductingmedium.This modelproposes
that the fastcomponeatsof theABR aregenerated
by the synchronized
propagation
of the
actionpotentialstravelingalongthe auditorybrain-stempathways.The
modelrepresents
anactionpotentialwith upto 100currentdipolestravelingalonga pathwaycorresponding
to a knownauditorybrain-stemtract.
Coordinatesof the majorfibertractsare obtainedfrom hamanbrainatlasesand adaptedto a sphericalhead model.Computationsassuming
classical interconnections
between brain-stem
nuclei show that such
synchronously
propagatingaction potentialscan generatewaveforms
similarto recordedABRs. Accordingto thismodel,positivepeakscorrespondtothedepolarizing
wavefrontof theactionpotentialwhilenegative
valleysare generatedwith the repolarizingphase.
StanfordUniversity,1980]haveresultedin conflicting
conclusions
about
whetherthisoccursfor monopolar
stimulation.
To address
thisquestion,
an eight-channel
electrode
arraywasacutelyplacedin thescalatympani
of sevencats.Recordings
werethenmadein the VIIIth nerve,of single
unit responses
to electricalstimulationfrom eachof the channelsin the
array.For eachunit isolated,thresholdcurrentfor hipbasicmonopolar
stimulation was determined for each of the electrode channels. Some units
werefoundtobehighlyselective
intheirresponse
tothedifferent
channels
of theelectrodearray,with themosteffectiveelectrodehavinga threshold
lowerthan an adjacentelectrodeby up to a factorof 5 times.Adjacent
electrodes
wereeither 1.0or 1.5mm apart.Other unitswerefoundnot to
beveryselective
in theirresponse.
Thissuggests
thatsomedegreeof spatial selectivity
isachievable
withmonopolar
stimulation.[ Worksupported by NIH.]
3:45
BBBI0. E!ectromagnet'cbasis of acoustic perception. I. Biological
BBB7. Steady-stateevokedpotentialsin sleepinghumansto continuous
modulated
tones.
Lawrence
T. Cohen
and
Field
W. Rickurals
structures.Glenn M. Cohen (Department of BiologicalSciences,
FloridaInstituteof Technology,
Melbourne,FL 32901)
(Departmentof Otolaryngology,
Universityof Melbourne,Parkville,
Australia 3052)
At a previousmeetingof the society,Rickuralsand Clark [L Acoust.
Soc.Am. Suppl.172, S54(1982)] showedthatsteady-state
evokedpotentialscouldberecorded
fromalerthumansin response
toamplitude-modu-
iatedtonesovera widerangeof modulation
frequencies.
A subsequent
paperhasshownthat,whilethereisanamplituderesponse
maximumfor
alert subjectsat a modulationrate of approximately40 Hz and this frequencyis thus appropriatefor optimumthresholddetection,different
circumstances
applyfor sleepingsubjects.
Sleepingsubjects
differfrom
alertsubjects
in bothamplituderesponse
andbackground
EEG noise,as
functionsof modulationfrequency.A detectionefficiencyfunctionre-
vealsthatduringsleeptheoptimummodulation
frequency,
dependent
on
Althoughhearingaidscancompensate
forsomehearingimpairments,
theycannoteffectively
compensate
for impairedfunctions
resulting
from
majorlosses
of haircellsand/or nerves.Cochlearimplantsarelimitedin
theireffectiveness
bythenumberof functional
cochlear
neurons,
surgical
techniques,
andcurrenttechnology.
Electromagnetic
waves,a newapproach,offerthepotentialofbypassing
theseverely
impairedcochleaand
directlysimulating
thehigherauditorycenters,
suchastheauditorycortex [P. L. StocklinandB. F. Stoeklin,TIT J. Life Set.9, 29-51 (1979) ].
Thisapproach
isbaseduponthefactthatexcitable
tissues
mayemitelectromagnetic
wavesduringthedepolarization
cycleduetoenergychanges
in theintegralmembrane
proteins.
In thispaper,theauditoryapplication
of electromagnetic
wavesisintroduced
byexaminingthebiological
structuresimportantto acousticperception.
stimuluscarrierfrequency,lieswell above40 Hz. For lowercarrierfrequencies
a peakoccursat about90 Hz, whileat higherfrequencies
the
optimummodulation
frequency
isashighas 150Hz. Thesehighermodu-
4:00
lation rates allow more efficient detection than does 40 Hz. Stimuli with
highmodulation
rateshavebeenusedsuccessfully
withsleeping
subjects
includingneonates.
BBBI1. Electromagneticbasis of acoustic perception. II. Physical
mechanisms.John G. Clark (Mentee, Inc., 8940 S.W. 129 Terrace,
Miami, FL 33176)
3:15
BBBS. AGC behaviorof a recoverymodelfor auditory nearon firings.
Timothy A. Wilson (Room 36-547, Department of Electrical
Engineeringand ComputerScience,and ResearchLaboratoryof
Electronics,Massachusetts
Instituteof Technology,Cambridge,MA
02139}
In a recoverymodel for auditory neuronfirings [ Westermanand
Smith. J. Acoust. Sue. Am. gl, 680-691 (1987); Johnsonand Swami, J.
Acoust.Soc.Am. 74, 493-501 ( 1983}], the firinghistorymanifestsitself
as a reductionin the instantaneous
probabilityof a neuralevent.In this
paper,it is shownthat the ensemblebehaviorof sucha modelmay be
interpretedas that of a feedbackautomaticgain control (AGC). The
AGC input is the excitationfunctionand itsoutputis the ensemble-aver-
agefiringrate.Theimpulseresponse
ofthegain-control
filterisa superpositionof time-invariantand time-varyingcomponents
that are relatedto
therecoveryfunction's
absoluteandrelative-refractory
intervals,respectively. In response
to a steplikeinput, the modei'soutputresembles
the
firing-rateresponse
of an auditoryneuronto a toneburst:Bothcontainan
exponentiallydecayingrapid transientwhosetime constantdecreases
as
the input sizeincreases.[Work supportedby DARPA undercontract
N00014-82-K-0727, monitoredthroughthe Officeof Naval Research.]
Sl 18
J. Acoust. Soc. Am. $uppl. 1, VoL 82, Fall 1987
A studyof physicalparametersleadsto the conclusionthat the human
skull,withbraintissueincluded,isa cavitythatwill supportelectromagneticstandingwavefieldsin the frequencyrangebetween200 MHz and 3
GHz. This frequencyrangecoincides
with allowabletransitionsin the
rotationalenergystatesof integralproteinsthat are embeddedin nerve
membranes.
Thisfrequency
overlappermitstheintegralproteinsto couple energybetweenpropagatingactionpotentialsand standingelectromagneticfieldswithinthe skull.This isa crucialphysicalmechanism
in a
full theoryorbrain functioningwhich accordsstandingEM fieldsa central rolein acousticperception.
All physicalmechanisms
will bediscussed
and relatedto biologicalstructuresin the brain. A key predictionof the
theoryisthatthefrequenc•ofthelowestEM standingwavemodeforany
individualcanbepredictedsimplywith knowledge
of thecephaltoindex.
Recentmeasurements
made on sevenindividualsconfirmthe theory.
[Work sponsored
by Mentee,Inc. ]
4:15
BBBI2. Effect of acoustictone perceptionon several higher modesof
brain-generatedelectromagneticwaves: Preliminary evidence.Pitilip
114th Meeting: AcousticalSociety of America
Sl 18
L. Stocklin(Consulting
physicist,
439BlueJayLane,SatelliteBeach,FL
32937)
Brain-generated
microwaves
weredetectedandmeasured
for eachof
twosubjects
for severalhighermodesin thefrequency
rangeof the7th13thprimary modeof the adult humanbrain ( 1200-1900MHz). Differeneesin modeamplitudeof 5-8 dB weremeasuredwith a loud acoustic
FRIDAY
AFTERNOON,
20 NOVEMBER
tonestimulusON andOFF. Highermodeamplitudechangeoccursimmediatelyupontonestimulusstartor stop.In orderto increase
higher
modepowerwellaboveambientnoise,a zeromode"pumping"
procedure
wasused.Intersubject
andcontrolsubject
comparisons
shownoacoustic/
microwave
crosstalk,
eithermechanical
or electrical.
No modeactivity
wasmeasureable
byanysubject
in themodefrequency
regionofanyother
subject,
withor withoutzeromodepumping.[Worksponsored
by Mentec, Inc. ]
1987
UM AUDITORIUM,
1:30 TO 4:05 P.M.
Session
CCC. SpeechCommunication
VIII: CrossLanguageandOther Studiesof Perception
D. Kimbrough Ollcr, Chairman
Mailman Centerfor Child Development,Universityof Miami, P. 0. Box 016820,Miami, Florida 33101
Chairman's Introductian--l:30
ContributedPapers
1:35
CCCI. Franco-American
differences in the discrimination of DA from
GA, FrancoisSanton(CNRS, Marseille,France) and Bertram Scharf
(CNRS andAuditoryPerception
Laboratory,
Northeastern
University,
ferredsomemurmurandacceptedbriefernasalizationin the vowel;and
Portugueseresponses
were intermediate.Preliminaryacousticdata from
utterances
in thethreelanguages
arein accordwiththeseperceptual
findings.
Boston,MA 02115)
2:05
Wesynthesized
DAs andGAs thatweresupposed
to differonlyin the
third formant, between2 and 3 kHz. Discriminationwas measuredin
narrow-band
noisemaskerscenteredon frequencies
from 1 to 3.5 kHz.
Thesign:d-to-noise
ratiowassettoyieldnearly100%correct
responses
in
theleasteffective
masker(at 3.5kHz) andnearly50% in themosteffectivemasker(at 1 or 2.5 kHz). ThreeAmericanlisteners
yieldedresults
similarto tuningcurves.Discriminationwaspoorestin the2.5-kHz noise
and improvedrapidly at lower and higher noisefrequencies.
Three
Frenchliisteners
gavesimilarresults,
butthreeothersgaveverydifferent
results.The signal-to-noise
ratios were.11 dB lower and discrimination
waspoorestin the 1-kHz noise.(One Americanalsodiscriminatedat the
lowersignal-to-noise
ratiowhengivenfeedback.
) Analysisof the tapes
revealeda low-frequency
clickin theDAs butnotin theGAs. Americans
did not usethis cue (without feedback).SomeFrenchalsodid not, but
others did. Apparently, becausenatural American DAs differ from
FrenchDAs, Frenchlistenersare morelikely to useartifactualcues.
1:50
CCC2.Perception
ofvowelna•alization
inVC contexts:
A cross-language
study. Kenneth N. Stevens(Room 36-517, Massachusetts
Institute of
Technology,Cambridge,MA 02139), Amfilia Andrede, and M.
C•u Viana(Centrode Linguistica
da Universidade
de Lisboa,Av. 5 de
Outubro,85-6,1000-Lisbon,
Portugal)
A seriesof stimulirangingbetween[tAt,x],[t7•t,], and [tAnt•] were
synthesi:,.ed
bysystematically
manipulating
( 1) thedurationof nasalizationin thevowel[ n], (2) theamountofnasalization
inthevowel,and( 3)
thedurationof thenasalmurmurfollowingthevowel.The stimuliwere
presented
to nativespeakers
of Portuguese,
English,andFrench,which
differwithrespect
totheoccurrence
ofnasalvowels
in theirphonological
systems.
The listeners
wereaskedto judge,for eachstimulus,( 1) the
presence
or absence
of nasalization
and (2) theadequacy
of thestimulus
as a natural utterancewith respectto its nasalization.The different lan-
guageg•oupsgavesimilarresponses
with regardto the presence
or absence
ofnasalization.
However,
judgments
ofthenaturalness
ofthestimtlli in the differentlanguages
dependon the temporalcharacteristics.
Frenchliisteners
preferred
a longerdurationof nasalization
in thevowel
andwereindifferent
to thepresence
of murmur;Englishlisteners
pre-
$119
J.Acoust.
Soc.Am.Suppl.1,VoL82,Fall1987
CCC3.Acoustic-phonetic
analysisof Spanish/I/. Miguelina Guiraoand
Enriquc A. Rosso (Laboratorio dc InvestigacionesScnsoriales,
CONICET, CC 53, 1453BuenosAires,Argentina)
Acousticmeasurements
to examinethe contributionof overlapping
segments--anticipatory
andcarryovercoarticulations--totheidentification of AmericanSpanish/1/wereperformed.The consonant
wascombinedwith five vowelsin naturallyproducedCV, VC, VCV, and CCV
syllables.
Acousticprofilesthroughanalysis
of formanttrajectories,
fundamentalfrequency,
intensityanddurationof vowel,consonant,
andtheir
overlapping
segments
wereobtained.In searching
for thecorresponding
criticalspectral
features,
digitalizedwaveforms
weremodifiedbydeleting
varioustemporalsegmentsin the syllable.The excisedsoundswere used
as stimuli in identifications tests. Results indicate that the duration of the
syllabicnucleivariesacross
front,roedial,andbackvowelsandalsoin preand post-vocalic
position.Segment/1/presentedin isolationis poorly
identified.Bestidentifications
areobtainedwhenthestimuliareintegratedbytheendoftheoverlapping
portionandthebeginning
ofthevowel.A
tradingoffrelationship
effectisobserved
betweenthesetwosegments.
2:20
CCC4. On the identificationof Spanish voiced stops. Jorge
A. Gurlekian,Miguelina Guirao,andHoracio Franco(Laboratoriode
Investigaciones
Sensoriales,
CONICET, CC 53, 1453 BuenosAires,
Argentina)
Experimentswereconductedto examinethe interactionbetweenrelevantacousticfeaturesof Spanish/b,d,g/emittedwith/a/in CV syllables and VCV combinations with the first or second vowel with stress.
Durationof steadyandtransitionalvowelsegments
andtheclosuredurationweresystematically
segmented
at particulartimeintervals.The entire
sequences
andsplicedsegments
werepresented
to nativeSpanishspeakers
for identification.
Resultswerepresented
asa ratiobetweendifferentclosuredurationsand the numberof roeslit periodsrequiredfor the identificationof thestop.Differentratioswereobtainedfor eachconsonantin the
CV syllable.Whenthe closureportionwasremovedcompletely,the un-
voicedcounterparts
wereaccurately
perceived.
Thiswasnottruefor/g/,
wheretheabsence
of the burstavoidedthe shiftingto/k/. For the VCVs
whentheclosureportionwasentirelyremovedandtheremaining
parts
114thMeeting:
Acoustical
Society
ofAmerica
Sl 19
wererejoined,
thestops--approximants
in thiscontext--were
stillidentified.Theseresultsshowedthat/b/and/d/identification wascuedby a
voicedportionpreceding
thetransitionof the followingvowel.Primary
featuresfor thesesoundswerelocatedin the transitionedges•final and
initial--whichoverlapped
bothvowelandconsonant
information.
2:35
CCCS. Training new fricative contrasts, Donald G. lamieson
(Department of CommunicativeDisorders, University of Western
Ontario, London, Ontario N6G
IHI,
Canada),
David Morosan
(Departmentof Psychology,
Universityof BritishColumbia,Vancouver,
Canada), and Susan Rvachew (Department of Psychology,University
of Calgary,Calgary,AlbertaT2N IN4, Canada)
A perceptualfadingtechnique[cf. Jamiesonand Morosan,Percept.
Psychophys.
40, 205-215 (1986) ] wasusedto train two typesof listeners
to perceivenewfricativecontrasts.One groupconsisted
of youngadult
francophones
who had difficultyproducingand perceivingthe voiced/
voiceless
"th" distinctionin English.With thisgroup,trainingusingthe
fadingtechniqueimprovedidentificationaccuracyboth for the specific,
synthetictargetsusedin training,andfor multiple,naturaltokensof these
sounds,spokenby differentindividuals,bothmenandwomen.However,
this learningwasquitespecific,as performance
waspoorwhenlisteners
weretestedwith the targetsoundsin new word positions,or when/d/
tokenswereusedin the distractorset.The secondgroupof listenerswere
youngchildrenwho consistentlymispronounced
at least one English
fdcativesound,and had beendiagnosed
ashavinga functionalarticulation disorder.A sizeableproportionof thesechildren,all of whomhad
beenselectedon the basisof productiondifficulties,displayedatypical
perceptualskills;for thesechildren,trainingproduceda measureable
improvementin identificationaccuracy,and in someinstances,
perceptual
training (without explicitproductiontraining) alsoimprovedthe productionsof thetargetsounds.[ Work supported
by NSERC AHFMR and
HWC:NHRDP.
]
theydosoby notingnative-language
(LI) phones
in theL2, or bynoting
divergences
from normsestablished
for phonesin the L2. Englishsenteneesspokenby Chineseand nativeEnglishtalkerswerepresentedto
threegroupsof listeners.
The Chineselisteners,
whospokeEnglishwith
strongforeignaccents,were able to distinguishChinesefrom native
talkers.Thoseexperienced
in EnglishresemblednativeEnglishlisteners
significantly
morethanthosewhowererelativelyinexperienced,
suggesting the experienced
Chineselistenershad developedtacit knowledgeof
howEnglishsentences
"ought"to sound.Removingpauses
fromthesentencesdid not affectforeignaccentscores,suggesting
that "fluency"and
"foreignaccent"representdifferentdimensionspertainingto L2 proficiency.Chinesetalkerswho learnedEnglishbeforethe ageof 12 years
receivedsignificantly
lowerscoresthan nativeEnglishtalkers.Learning
an L2 before12 years•the ageoftenassociated
with the endof a "critical
period"•does not guaranteeaccent-freepronunciation.There was no
differencein foreignaccentscoresobtainedfor adult Chineselearnersof
Englishwhohadlivedin theUnitedStatesfor 1and5 years.This suggests
that amountof (unaided) L2 experiencemay not improveL2 pronunciation, at leastbeyonda certainpoint.
3:20
CCC8. Perceptual segregationof concurrent vowels. Peter F. Assmann
and QuentinSummerfield(MRC Institute of Hearing Research,
UniversityPark,NottinghamNG7 2RD, England)
The abilityto grouptogethertheacousticcomponents
of a voiceand
segregate
them from competingvoicesis an importantskill in speech
communication.
To studytheauditoryprocesses
involved,pairsof vowels
werepresented
simultaneously
to listeners
withnormalhearing.Identificationperformance
improvedas the fundamental-frequency
difference
betweenthe membersof the pair increased.Two auditorymodelswere
comparedto predictthis result.The compositewaveformwas passed
throughanarrayofbandpass
filterssimulating
thecat'slimitedfrequency
resolution.The "place" model estimatedthe two fundamentalsfrom
peaksin the profileof the rmsoutputsof the filters.It thensampledthe
2:50
CCC6. The role of duration in the percel•tion of consonantswithin
reducedsyllables. Dani•le Archambault (Universit6 de Montr6al and
INRS-T616communications, 3 Place du Commerce, Nuns' Island,
Montreal, QuebecH3E I H6, Canada)
The roleof durationasa perceptualcueto the presence
of two underlying consonants
versusone is examinedin Montreal French. Due to
deletionof the interveningphoneticsegments,two identicalsyllable-initial consonants
may bejoined in onearticulationsuchthat, for example,
two plosivesshowa singleburst.A seriesof utterancesin which these
doubleconsonants
and the corresponding
singleonesappearin identical
segmental
contextswererecordedandthenpresented
to listeners
in perceptualtests(e.g., la plupart (mostof it)•/laplypar/•
[lap:at] as opposedto la part (the part) •/lapar/•
[lapar] ). To insurethat listeners
basetheir judgmenton durationto distinguishbetweenthe utterances,
theywerealsopresented
with thesamesentences
in which,byuseof signal
processing,
thedurations
of theconsonants
wereinverted,i.e.,thedouble
consonant
wasgiventherelativedurationof thesingleconsonant
andvice
versa.Resultsshowthat while a longdurationconsistentlyleadslisteners
to recognizea doubleconsonant,a shortdurationdoesnot automatically
promptthem to identifya singleconsonant.Resultsalsoindicatethat
consonantduration mustbeconsideredin a contextlargerthan that of the
syllable.[Researchdoneat the Universit6de Montr6al and supportedby
National ResearchCouncilof Canadaand Qu6becGovernment.]
3:05
CCC7. Non-native speakers can gauge degree of foreign accent in
English.JamesEmil Flege (Departmentof Bioeommunieation,
UAB,
UniversityStation,Birmingham,AL 35294)
Previousresearchindicatedthat non-nativespeakers
candetectforeignaccentin theirsecond
language(L2), evenif theythemselves
speakit
with an accent.This studyusedintervalscalingto helpdeterminewhether
S120
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall 1987
profileat integermultiplesofeachfundamental
to reconstruct
thespectra
of the constituentvowels.The "place-time"modelestimatedthe fundamentalsfromdominantperiodicities
in thewaveformsemergingfromthe
filters.The amountof synchronization
to eachfundamental
wasplotted
as a functionof filter centerfrequencyto reconstruct
the spectra.The
place-timemodelestimatedthe two fundamentalsmore accuratelythan
the placemodel,and predictedidentification
responses
moreprecisely.
This outcomeis compatiblewith the ideathat a temporalanalysisis involvedin the segregation
of concurrentsounds.
3:35
CCC9. Dichotic du!fiex pertelation and modularity. Ignatius
G. Mattingly (HaskinsLaboratories,270 Crown St., New Haven, CT
06511)
Recentwork suggests
that dichoticduplexperception(in whichthe
sameacousticmaterialsimultaneously
yieldsbotha phoneticand a nonphoneticpercept)occurswhenthe source-defining
or source-localizing
processes
are givenecologicallyiraplausibleinformation,and provides
furtherevidence
for themodularityofspeech
perception.
IfF 3 andF I-F 2
of a synthetic syllable are presenteddichotically, with identical F0 con-
tours,onehearsjust the expectedsyllableat somefixedpositionwithin the
head.With a somewhat
higherF0 contouronF 3 thanonF 1-F 2, onehears
two voices,oneat eachear, both sayingthe syllable.But with a considerablyhigherF 0 contouronF 3, perception
isduplex:onehearsa buzzat the
F 3earandthesyllableat theF 1-F2 ear.And if, instead,thebasicpatternis
modifiedbyshiftingF 3 abruptlyto the F 1-F 2 earafter80 msor more,one
hearsjust the syllable,now moving acrossthe head. But if F 3 is shifted
sooner,perceptionis againduplex:onehearsa chirp at the ear initially
receivingF3 and the syllableat the otherear. Evidently,sufficientlyextremeconditionsdisruptsourcedefinitionor sourcelocalizationwithout
disruptingdichoticspeechperception.Speechperceptionappearsto be
independentof theseother modularprocesses,
and thereforemodular
itself. [Work supportedby NIH Grant HD-1994.]
114thMeeting:AcousticalSocietyof America
S120
3:50
CCC10.Synthesis
andperception
of paragraph-level
prosody.Kim E.
A. SilveJ•an (Room 2C-440,AT&T Bell Laboratories,
600 Mountain
Avenue,Murray Hill, NJ 07974)
graph textswere constructed:In each text the overall meaning(e.g.,
wherea speaker's
turn finished)depended
on thelocationof oneparticular paragraphboundary.In a seriesof perception
experiments,
listeners
heardoneor anotherversionofeachtextspoken
bya formantsynthesizer,
and answeredforced-choice
comprehension
questions.
Overall results
showed
that(i) listeners
doexploitsuchwide-domain
prosod
icorganizaDiscourse
structuresystematically
influences
the prosodyof utter-
ances.
in thisstudy,
units
ofprosodic
structure
thatspan
multiple
sentences(prosodicparagraphs)weresynthesized
by (i) temporarilyincreasing
•lheoverallpitchrangeat thestartof a (textual)paragraph;
(ii)
graduallydecreasing
the rangeovera fixedtime windowat the end;and
(iii) lengthening
the pauseat the boundary.Six ambiguous
multipara-
FRIDAY
AFTERNOON,
20 NOVEMBER
tion whencomprehending
extendedpassages
of connectedspeech,(ii)
the structurecanbesignaledby FO alone,although(iii) the moreredundantlyit isencoded,
thebetterit will beperceived.
Suchprosodic
structure
alsoimprovesthenaturalness
of synthetic
speech.
The resultsarguethat
prosodyis hierarchicallyorganized,rather than being a strictly linear
sequence
of intonationalphrases.
1987
UMS 4 AND 5, 1:30 TO 5:00 P.M.
Sessiion
DDD. UnderwaterAcousticsX: BottomInteractingOceanAcousticsII (Pr6cis-PosterSession)
GeorgeV. Frisk, Chairman
Bigelow208, WoodsHole Oceanographh:
Institution,WoodsHole, Massachusetts
02543
Chairman's
Introduction--l:30
ContributedPapers
Followingpresentationof the pr6cis,posterswill be on displayuntil 5:00 p.m.
1:35
1:43
DDD1. Computationof the Blot coefficients.B. Yavari and A. Bedford
(Departmentof AerospaceEngineeringandEngineeringMechanics,The
University of Texas, Austin, TX 78712)
DDD3. Seabed characterization from normal incidence reflectivity.
To apply the Biot theory to the studyof the interactionof acoustic
waveswith oceansediments,the coefficients
in the equationsmust be
evaluated.The coefficients
dependon the frequencyand the fabric,or
microstn•cture,
of the sediments.
A methodfor evaluatingthe dragand
virtualmasscoefficients
hasrecentlybeendeveloped[A. Bedfordetal., J.
Acoust.Soc.Am. 76, 1804-1809(1984) ]. The methodrequiressolving
for themotionof thefluidin theporeswhenthesolidconstituent
is subjectedto a spatiallyuniform,oscillatorymotion.The finiteelementmethod hasbeenusedto determinethefluid motion.The dragandvirtual mass
coefficients
have beendeterminedfor a variety of two-dimensionalpore
geometries.
It wasfoundthat thedragcoefficient
is insensitive
to thepore
geometry,while the virtual masscoefficientis very sensitiveto the pore
geometry.It wasdeterminedthat the coefficients
are independent
of the
frequencyup to a characteristicvalueof dimensionless
frequencyand
exhibita bilineardependence
on frequency.[ Work supportedby ONR. I
The
effects
of seabed interaction
on air-to-water
sound
transmission.
David M. F. Chapman(Institute of Soundand Vibration
Research,
The University,Southampton
SO95NH, UnitedKingdom)
The presenceof a reflectingseabedaltersthe transmission
of sound
fromanair-bornesourcetoa water-borne
receiver.
Resonances
in a planewave transmissioncoefficientcorrespondto excitationof the acoustic
normalmodesin the waterlayer.Althoughthe air-bornesourceexcites
thesamenormalmodesasa water-borne
source,theamplitudeandphase
of the excitation coefficients are different. There are some notable effects:
the weakdependence
of transmission
lossuponsourceheight,the preferred excitationof high-ordermodes,and the 25 log R dependenceof
transmission
lossuponrangein the mode-stripping
regime.The predictionsof a simplenormal-modetransmission
lossmodelare presented,
includingrealisticabsorption
in theair andat theseabed.[ Work supported by the:U.K. Ministry of Defence,throughthe Royal Aircraft Establishmentat Farnborough.
$121
Surficialvaluesof sedimentcompressional
velocity,density,and rms
interfaceroughness
are estimated
from thecoherentcomponent
of normal incidencereflectivityin the frequencyrange 10-1000 kHz. The
Kirchhoffapproximation
is employedfor the scattering
functionin the
inversionalgorithm such that the coherentreflectioncoefficientis as-
sumedto be dependenton the d•stributionof the bottomheightsand
independent
of theshapeof thebottom.Thefunctionalformof thereflectiondatasuggests
thatthedistribution
of bottomheightsfollowsa Laplaclanrather thanGaussianform for a varietyof sedimenttypes.Laboratory analysisof bottom core samplesprovidedthe meansfor quantitative
evaluationof velocityand densitypredictions.
1:47
DDD4. A numerical treatment of the fluid/elastic interface under range-
1:39
DDD2.
Charles W. Holland and Burlie A. Brunson (Planning Systems
Incorporated,7925 WestparkDrive, McLean, VA 22102)
J. Acoust. Sec. Am. Suppl. 1, Vol. 82, Fall 1987
dependent
environment.
Er-changShang(Yale University,Department
of ComputerScience,New Haven,CT 06520) and Ding Lee (Naval
UnderwaterSystemCenter,New London,CT 06320)
The actualphysicalproblembecomesconsiderably
difficultand complicatedwhena fluid mediumis interfacingwith an elasticmediumunder
range-dependent
environment.
In thiscase,a setof three"continuityconditions"musthold: ( 1) the continuityof verticalcomponents
of displacement, (2) the continuityof verticalcomponents
of stress,and (3) the
horizontalcomponents
of stressmustvanishontheinterface.The implicit
finite difference(IFD) scheme,usedto treat the fluid/fluid interface IS.
T. McDaniel and D. Lee, J. Acoust. Soc. Am. 74, 855 (1982) ] can be
extended to treat the fluid/elastic interface with some modifications. In
elasticinterfaceundera range-dependent
environment.An attractivefeatureof thisnumericalmodelis that it is readilyadaptableinto the existing
IFD code without excessiveeffort. Somecomputationalproblemswill
this
present
anumer
proce
is
prop
to
tre
th
flu
also be discussed.
114th Meeting: AcousticalSociety of America
S121
1:$1
DDD5. Transmissionof sound and beams through a water-sediment
interface. T. G. Muir and N. L. Lunde (SACLANT ASW Research
Centre,I- 19026La Spezia,Italy)
Thecomputations
of SchmidtandJensen[J. Acoust.Soc.Am. Suppl.
1 76, SI0 (1984) ] are extendedto examinethe penetrationof sound
beamsintoa sandanda mudsediment
asa functionof frequency,
grazing
angie,beamsize,andpulseshape.The computations
are madewith the
SAFARI model,an exactnumericalsolutionto the waveequationin
horizontallystratifiedenvironments.The effectsof sedimentattenuation
andrigidityareaccounted
for. Beamshapecontoursandlosscoefficients
in transmission
throughtheinterfacearepresented.
The effectof interface
transmission
ontheintegrityofpropagating
pulsewaveforms
isdiscussed.
It isshownthatdecreasing
thefrequency
to thelowkHz rangeenhances
the penetrationinto rigid sediments
at low grazingangles(belowthe
criticalgrazingangle).However,thisresultsin a geometric
dispersion
effecton the transmittedwaveforms,which destroysthe coherenceof
pulsedsignals.
1:55
DDD6. Bottom interactingpulsepropagationin the ocean.Michael
D. Collins (Department of EngineeringSciencesand Applied
Mathematics,NorthwesternUniversity,Evanston,IL 60201)
The parabolicequationmethodwasfirstappliedto underwater
sound
propagation
by F. D. Tappert.It hassincebeenrefinedandbenchmarked
intoa valuable
toolforfrequency
domaincalculations.
Development
ofan
equivalentnonlinearmethodin the time domainwasinitiatedby B. E.
McDonald and W. A. Kuperman.A linear versionof this methodhas
beendevelopedto handlebottominteraction.The newmodelallowsden-
sityandlosstobefunctions
ofdepth.Lossisaccounted
forin theproper
mannerfor typicaloceansediments.
Lossper meterincreases
linearly
withfrequency.
A newinitialfieldhasbeenderivedusingthemethodof
suredabsorption
values,that theyexhibita maximumat 1750-mdepth,
andthatthebehaviorof thismaximumisconsistent
withotherpublished
measurements
andtheories.Third, Biotestimates
of shearwaveabsorption are presented.Finally, a physicalmodel for the contact factor is
presented.
2:07
DDD9. Determinationof oceanbottom sound-speed
profilesusing a
modal inverse technique in a range-dependentshallow water
environment.George V. Frisk, JamesF. Lynch, and $ubramaniam
D. Rajah (Department of Ocean Engineering, Woods Hole
OceanographicInstitution,WoodsHole, MA 02543)
A modalinverse
technique
fordetermining
ocean
bottom
sound-speed
profilesis appliedto experimental
data obtainedin a range-dependent
shallowwaterenvironment.
The methodconsists
of towinga cw source
awayfrommooredreceivers
to obtaina well-sampled
measurement
of the
complexpressureversusrange.The Hankel transformof the measured
fieldthenyieldsthe depth-dependent
Green'sfunctionversushorizontal
wavenumber,
whichcontains
distinctpeaksat themodaleigenvalues.
The
eigenvalues
are usedasinputdatato a perturbative
inverseschemethat
generatesthe sound-speed
profileof the bottom.Data at 140and 220 Hz
wereobtainedin May 1984in NantucketSound,MA in an areawherethe
depthchanged
abruptlyat aboutthemidpointof theexperimental
track.
An associated
change
in bottomproperties
wasassumed,
andtheconcept
of localmodaleigenvalues
yieldinglocalgeoacoustic
parameters
wasthen
usedto determine
separate
modelsfor thetworegions.Excellentagreementbetween
thepressure
fieldscomputed
forthisrange-dependent
model usingadiabaticmodetheoryand the experimentally
measuredfieldsis
demonstrated.
2:11
impulse
response
obtained
by it intoa cwresponse
andcomparing
with
DDDI0. Modelanddatacomparison
for bottombackscattering.
Darrell
R. Jackson
(AppliedPhysics
Laboratory,
Collegeof OceanandFishery
Sciences,
Universityof Washington,Seattle,WA 98195) and Kevin
B. Briggs(Naval OceanResearchand DevelopmentActivity, NSTL,
normalmoderesults.[Work supported
by ONR.]
MS 39529)
matchedasymptotics.
Numericalmethodssuitedto linearacoustics
have
beenimplemented.
Themethodhasbeenbenchmarked
byconvolving
an
Acousticandgeoacoustic
datafrom two siteshavebeencompared
1:59
DDD7.
Acoustic transmission across the water/sediment interface
measuredduring in situ experiments.Lawrence J. Satkowiak (Naval
CoastalSystemCenter,Code4120, PanamaCity, FL 32407-5000)
A series of acoustic measurements were made to measure the trans-
missionof acousticenergyacrossthe water/sedimentinterface.The in
situmeasurements
utilizeda three-dimensional
arrayof hydrophones
as
acoustic receivers buried in the sediment. The acoustic sources were
mounted on a movable tower located on the seafloor. The transmission
wasmeasured
asa functionof grazingangle,frequency,
andpulseshape
for two distinctlydifferentsedimenttypes,namely,fine sandand soft
mud.The experimental
resultspresented
will becomparedto predictions
madeusinga simplemultilayeredmodelthat treatsthe bottomasa series
of contiguous
layerswith knownacoustical
properties.
with a model [D. R. Jacksonet al., J. Acoust.Soc.Am. 79, 1410-1422
(1986)] for bottombackscattering
strengthat highfrequencies.
At one
site,thesediment
wasa finesandwithprominent,
directional
ripples.At
the other site,the sedimentwasa mixtureof clay, sand,and shell.The
geoacoustic
datawereusedtoobtainvaluesforthefollowingmodelinput
parameters:
sediment
soundspeed,sediment
massdensity,andthepower
spectrum
for bottommicrorelief.
The modelalsorequiresa sediment
volumescattering
parameter,
whichwasobtainedby fittingbackscattering
data.Themodelgenerally
gavegooddescriptions
ofthelevelandgrazing
angledependence
of thebackscattering
strength,andtheresultsindicate
thatroughness
scattering
wasdominantat thesandysite,whilesediment
volumescattering
wasdominantat theclayeysite.At thesandysite,the
microreliefspectrumshowedappreciableanisotropyand an unusually
rapid falloff with increasingspatialfrequency.For this site, the back-
scattering
modeloverestimated
boththedegree
of anisotroPy
(nonewas
observed)and the levelof scatteringat the highestfrequencies.
[Work
supportedby ONT and NORDA. ]
2:03
2:15
DDD8. Modelingdepth-dependent
absorptionin marinesediments.Paul
R. Ogushwitz (76 Cedar Lake West, Denville, NJ 07834)
Blotmodelestimates
of absorption
areparticularlysensitive
to porosity and to the frame moduli. In previouswork [P. R. Ogushwitz,J.
Acoust. Soc. Am. 77, 429-464 (1985)], the frame moduli from a self-
consistent
theoryof composites
(SCT) wasestimated,and an empirical
factor (the "contact factor") that scalesthe SCT estimatesin order to
DDDI1. High temporal resolution observations of hi•h-frequcncy
acoustic bottom echoes. Thomas L. Clarke, John R. Proni (Ocean
AcousticsDivision, NOAA/AOML, 4301 RickenbackerCauseway,
Miami, FL 33149), and Lloyd Huff (NOAA/NOS/C_&GS, 6001
ExecutiveBoulevard,Rockville, MD 20850)
matchmeasuredwavespeedswasdetermined.It isshownthat the contact
factoris relatedto grainpackingandcementation.
Here, it is firstshown
that Blot modelestimatesof soundspeedversusdepth do agreewith
measurementsin Gulf Coast brine sands[ G. H. F. Gardner et al., Geophysics39, 770--780(1974) ], wherethe SCT estimateshavebeenscaled
bytheappropriatecontactfactor.Second,it isshownthatthecorrespond-
Acousticbottomechoesat frequencies
from 10 to 380 kHz wererecordedfor a varietyof bottomtypesin southernChesapeake
Bay.Short
pulselengthsanddirectdigitalrecording
allowedtemporalresolution
of
100psto beachieved.Supportingmeasurements
of sedimentcharacteristicsandbottomroughness
allowedcomparison
of themeasurements
with
theory.The fieldobservations
werein goodagreement
with the theory
after corrections
for the interactionof transducerbeampatternswith
ingBlotestimates
ofabsorption
versus
deptharewithintherangeofmea-
bottomroughnessweremade.
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J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
114thMeeting:Acoustical
Societyof America
$122
2:19
DDDI2. High-resolution acoustic bottom roughnessmeasurementin
supportof bottomechointeractionmodeling.W. P. Dammannßand C.
A. Lauter (Ocean Acoustics Division, NOAA/AOML,
4301
RickcnbackcrCauseway,Miami, FL 33149)
A high-resolution
acousticbottomprofilerusingan extremelynarrow-beam,3-MHz echosounderwasdevelopedat the OceanAcoustic
Division of NOAA/AOML.
The device was used to measure bottom
roughnv;sover a rangeof scalesfrom lessthan I cm to severalmeters.
Roughness
measurements
weremadein the lowerChesapeake
Bay area
overmud, fine to mediumgrain sand,and coursegrain sand.The data
produced
wereusedto appraise
theperformance
of an acoustic
echoformationmodelthatpredictstheeffectsof marinebottomcharacteristics
on
a reflectedacousticpulseenvelope.Major aspects
of thedesignanduseof
the system,procedures
for processing
generated
data,and examplesof
processed
outputare presented.
isa featureless,
gentlyslopingplatformboundedby the8- and 16-mdepth
contours.Sedimentson this platformconsistalmostentirelyof mudsaccumulatedduringtheHolocenerisein sealevel.This areahasbeenexten-
sivelysurveyedusing5- and 27-kHz seismicreflectionprofilingequipment.While generallyrevealingonly minor reflectorsin the mudswhich
overliethepre-Holocene
erosionsurface,certainareasconsisted
of acousticallyimpenetrablesediments.X raysof corescollectedfrom theseareas
showednumerousgas-filledvoidsin the sediment.Streamchannelmarginsare evidenton the pre-Holoceneerosionsurface,and the gaseous
zonesare confinedbetweenthesemargins,althoughthe bottom of the
channels
cannotbeobserved
dueto theacoustic
impenetrability.
Thegas
zones are traceable and form an interconnectednetwork, one of which
connectsto a presentday uplandstream.
2:35
DDD16. A comparisonof measuredbackscatterstrengthswith the firstand second-order terms of a Neumann series solution to the Helmholtz
scattering integral. Richard Keiffer, M. F. Werby (NORDA
Numerical Modeling Division, NSTL, MS 39529), and Steve Stanic
2:23
DDD13. Characterization of seafloortype and roughnessfrom 12-kHz
acoustic backscattering measurements.C. de Moustier (Scripps
Institution of Oceanography,A-005, La Jolla, CA 92093) and
D. Alexandrou (Department of Electrical Engineering, Duke
University,Durham, NC 27706)
Seafloor acoustic backscatter measurements were carried out with 12-
kHz seabeammultibeamecho-sounders
overa varietyof terrainsincluding pelagicsediments
on the top of two seamounts
in the tropicalNorth
Pacific;bemipelagic
sediments,
lava flows,and debrisflowson the East
rift zoneof the Kilauea volcano;and a manganese
nodulefield in the
tropicalNortheasternPacific.Thesedata are subjectedto statisticaltests
for homogcncity
andstationarity,andsidelobeinterferencecancellationis
performcdthroughadaptivefiltering.Thesemeasurements
arcthcnuscd
tocomparethe 12-kHzacoustic
signature
of theseterrainsbasedonstatis-
(NORDA
Ocean AcousticsDivision, NSTL, MS 39529)
In previousASA meetings,a roughinterfacescatteringmodelunder
developmentat NORDA hasbeenreported.This modelmakesuseof
Brekhovskikh'stangentplaneapproximationfor the total field near the
scatteringsurfacein the Helmholtzintegralequation.Direct numerical
integrationis thenperformedyieldingthe first-orderterm of a Neumann
series solution for the scattered field. Furthermore, as has been shown,
this model also calculates a second-order term via Neumann's successive
approximationtechnique.Physically,this second-order
approximation
beginsto accountfor secondaryscatterings
as well as amelioratingthe
initial tangentplaneapproximation.In thismeeting,the first-andsecondordermodeledresultswith backscatterstrengthsrecentlymeasuredoff of
PanamaCity, FL, by NORDA's OceanAcousticsDivisionwill be compared.
ticsoftheamplitude
andthephase
oftheechoes
received
atdiscrete
angles
of incidence
in theinterval + 20'.Implicationsfor bottomtypeidentification aswell assurfaceroughness
determinationarediscussed.
[Research
fundedby ONR. ]
2:39
DDD17. Correctingthe Kirchhoffroughboundary.Interactionmodelfor
scattering.JohnJ. McCoy (The CatholicUniversityof America, Civil
Engineering,
Washington,DC 20064)
2:27
DDD14. Geoacousticpropagationthroughrandomseafloormodels.M.
E. Dougberty and R. A. Stephen (Woods Hole Oceanographic
Institution, Woods Hole, MA 02543 )
Finite differenceforwardmodelsof elasticwavepropagationthrough
laterallyheterogeneous
upperoceaniccrustare presented.
The finitedifference tbrmulation
is a two-dimcnsional
solution to the elastic wave
equationfor heterogeneous
mediaand implicitlycalculatesP and SV
propagation,
compressional
to shearconversion,
interference
effects,
and
interfacephenomena.
Randomvelocityperturbations
with Gaussianand
self-similarautocorrelationfunctionsanddifferentcorrelationlengthsare
presented
thatshowdiffcrent
characteristics
ofsecondary
scattering.
The
presence
of a water-solidinterfacein themodelsallowsfor theexistence
of secondaryStoneIcywaves,which accountfor much of the seafloor
noiseseenin the syntheticseismograms
for the laterally heterogeneous
models. "Random" incoherentsecondaryscatteringincreasesas the
productof wavenumber
andcorrelationdistance(ka) approaches
1. Deterministicsecondary
scatteringfrom largerheterogcneities
is the dominant effectin the modelsas ka increasesabove 1. Secondaryscattering
alsoshowsup asincoherence
in the primarytracesof the seismograms
when comparedto the laterallyhomogeneous
case.Cross-correlation
analysisof thc initial P-divingwavearrivalshowsthat, in general,the
correlationbetweentracesdecreases
aska approaches
1.
2:31
DDD15.
Acoustic investigation of Palco-drainage networks in central
ChesapeakeBay. Jeffrey Halka (Department of Natural Resources,
Maryland Geological Survey, 2300 St. Paul Street, Baltimore, MD
21218) •tnd D. L. Gardner (NOAA, N/CGx3, Rockville, MD 20852)
Locatedwestof the deepaxial channelin the centralChesapeake
Bay
S123
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall 1987
The Kirchhoffroughboundaryinteractionmodelis an incomplete
largek approximation,
whichdoesnot incorporate
eithershadowing
or
multipleinteraction
effects.
Numericalimplementation
suggests
that,of
thesetwo shortcomings,
the neglectof shadowing
is the moreimportant.
Accordingly,attemptshavebeenmadeat correctingthe Kirchhoffmodel
by introducing
a shadowfunction.For statistical
formulations,
thisintroductionisfrequently
accomplished
aftertheincorporation
of a statistical
average.
Thisis inconsistent
withtheunderlying
physics.
Here,shadow
functions
areshownto havea rigorousbasisasstatistical
measures
of the
roughboundarygeometry,independent
of any scatteringexperiment.
That is,onecandefinea suiteof statisticalmeasures
of theroughboundary geometry,whichcansubsequently
beinterpretedasshadowfunctions
in the contextof a scatteringexperiment.The particularstatisticalmeasurethat is appropriatefor a gpecificexperimentis determinedby the
statisticof the acousticsignalto be estimated.
2:43
DDD18. Soundscatteringfrom a randomlyroughfluid-solid interface.
Dalcio K. Dacol and David H. Bennan (Code 5160, U.S. Naval
ResearchLaboratory,Washington,DC 20375-5000)
A generalformalismfor acousticscatteringfrom a fluid-elasticsolid
interfaceisdeveloped.
The theoryparallelsWaterman'swork [ P. C. Waterman, J. Acoust. Soc. Am. 45, 1417 (1969)], based on the extinction
theorem, for acousticscatteringfrom inpenetrablesurfaces.This formal-
roughfluid-solidinterfaceby usingperturbationtheoryto solvetheequationsfor the scatteringamplitudesto secondorder. The Watson-Keller
renormalizationansatz [J. G. Watson and J. B. Keller, J. Acoust. Soc.
Am. 74, 1887(1983) ] isthenusedto accountfor somemultiplescattering
ism
is
then
used
to
study
the
scatte
of
soun
wav
fro
aral
114th Meeting:AcousticalSocietyof America
$123
2:55
effects
beyond
double
scattering.
A numerical
study
ispresented
comparingacoustic
scattering
in thefluidfroma fluid-solidinterfacewithacous-
ticscattering
in thesame
fluidfroma hard,impenetrable
surface
(Neumannboundary
condition).Substantial
differences
between
thetwocases
arefound.
Besides
theexpected
acoustic
energy
lossbytransmission
into
thesolid,
it wasalsofound
thattheangular
distribution
oftheremaining
DDD21. A $-MHz acoustic concentrationmeter that measures
suspended
sand.
DanielM. Hanes(Division
ofApplied
MarinePhysics,
Rosenstiel
School,
University
ofMiami,4600Rickenbacker
Causeway,
Miami, FL 33149)
acoustic
energy
thatisreflected
andscattered
bythefluid-solid
interface
A 3-MHz acoustic
concentration
meter(ACM), whichmeasures
the
differs
greatly
fromthehardimpenetrable
surface
case,
especially
near
intensity
ofbackscattered
acoustic
energy,
hasbeen
deployed
inthelaboratory
andinthefieldinorder
toestimate
theconcentration
ofsuspended
grazing
incidence
andscattering
angles.
sand.Techniques
for measuring
the profileof theconcentration
of suspendedsandcloseto the seabedwith a verticalresolutionof about I cm
2:47
DDD19.
Resonance interaction of sound waves with a stratified seabed.
Greta Conde, P. D. Jackins, and G. Gaunaurd (Naval Surface
WeaponsCenter,White Oak, SilverSpring,MD 20903-5000)
A novelapproachto analyzethereflectionandtransmission
of sound
wavesfrom a penetrableand layeredfleetinterfacebetweentwo mediais
described.
Thisapproachgeneralizes
thefirst-orderpredictionof theresonancescattering
theory(RST), whichwasdeveloped
earlierforstacksof
arbitrarilymanyelasticplatesseparating
dissimilarfluidmedia [Jackins
andGaunaurd,J. Acoust.Soc.Am. 80, 1762-1776(1986)]. Thegeneralizationconsists
of twoportions.The firstonemakesthelowerfluidmediumbecomeanelastichalf-space,
whichmakesthemodelusefulto predict
reflectionsfrom a stratifiedoceanbottom.This portionwasbrieflyanalyzedearlier[J. Acoust.Soc.Am. Suppl.180, S116(1986) ]. The second
portion,nowmarriedto thefirst,consists
in a second-order
approxima-
tionfor theparameters
involvedin thedescription
of thebottomreflection/transmissioncoefficients,which retainssecond-ordertermscontain-
ingsecond
derivatives
of thepertinentparameters.
Thisisanapplication
to flat, layeredmediaof an (second-order)
acoustical
counterpartof an
R-matrixformulation
formany-body
scattering.
It isshownhowthepresentgeneralization
contains
theearlierfirst-order(RST) prediction
asa
particularcase,andhow it improvesits accuracywith a relativelyminor
additional calculational
effort.
2:51
DDD20. A scattering function for histuric reverberation calculations.
Dale D. Ellis (Defence ResearchEstablishmentAtlantic, P.O. Box
1012, Dartmouth, Nova Scotia B2Y 3Z7, Canada) and D. R. Haller
(Defence Research EstablishmentPacific, FMO, Victoria, British
Columbia V0S lB0, Canada)
The oceanbottomscattering
functionS(O,•;O',•') depends,
in general,onthegrazingangles8, 8' andazimuthalangles•b,•' of theincident
and scatteredenergy.However,mostmeasurements
are for backscatter
only:B(8) ---S(0,•b;0Ab
+ •r). The few availablegeneralmeasurements
indicate strong forward scatteringnear the specularangle (•'= •,
•' = •), andweaker,azimuthallyisotropic,diffusescatteringawayfrom
the specular.The proposedfunctioncombinesLambert'slaw with Brek-
hovskikh
andLysanov's
surface
scattering
function,giving
S(O,•;O',•') =/• sin0 sin0' + v( 1+ Aft)2
Xexp[ - (l/2o•)Af•],
where Af• = [cos:0 + cos
20' -- 2 cos• cos0' cos($-- ½Y)]/(sin0
+ sin0') 2.Byfitting/•,*,,crtothebackscattering
measurements,
a general scatteringfunctionis obtained.This is an improvement
over two
commonmethodsof extrapolatingbackscattering
to generalscattering.
In particular,one commonmethodusesthe separableapproximation
x/B(0)B(0'), whichpeaks
at •' = •r/2,ratherthanatthespecular
angle.
Another common method uses the half-angle approximation
B[ «( 0 + 0') ] whichpeaksat thecorrectin-plane
grazingangle(if 0' is
replaced
by •- - 0' for forwardscattering),
butfailsoutof plane.
S124
J. Acoust.Soc.Am.Suppl.1, Vol.82, Fall1987
arediscussed.
Thescattering
characteristics
ofsuspended
sandin a laboratorytank wereusedto providea methodof calibrationfor the ACM.
Thedependence
ofthescattering
coefficients
uponsediment
sizewasalso
investigated.
TheACMwasdeployed
inthesurfzoneatStarthope
Lane,
PrinceEdwardIsland,Canada,
in October1984.In thesurfzone,the
limitations
of suchprofilometers
are (a) air bubbles
injected
intothe
waterbybreaking
waves,
and(b) thepossible
variations
in sandsizewith
height
above
theseabed.
[Worksupported
byNavalFacilities
Engineering Command.]
2:59
DDD22. Modeled effectsof seaflooranisotropyusingthe facet-ensemble
methodand comparisonwith Red Sea data. Henry F. Schreiner(Naval
OceanResearchandDevelopmentActivity, Code245,NSTL, MS 395295OO4)
Bathymetricmeasurements,
aswellasa knowledge
of the formation
processes
involvedin shapingthe oceanbottom,haveindicateda strong
anisotropy
in bottomroughness
overmuchof theworld'soceans[C. G.
Fox and D. E. Hayes,Rev. Geophys.23, 1-48 (1985) ]. This anisotropy
canbeapproximated
bya ridgeor troughora series
&ridgesandtroughs.
The facet-ensemblemethod computesthe three-dimensionalcomplex
acoustic
pressure
froma signalthathasbeenscattered
andreflectedfrom
thiskind of surface[ W. A. Kinney et al., J. Acoust.Soc.Am. 75, 183-194
( 1983) ]. The modelhasbeenadaptedto a side-scanning
sonarof frequency 3.5kHz andhorizontalandverticalbeamwidthsof 10'and30ø,respectively.The computation
isdrivenbya 100-mssourceandsampledat a rate
of 128/s.Comparisons
are madewith experimentaldatafrom the highly
lineat•',.d
Red SeaChannel.A one-to-onecorrespondence
betweenthefeatureson theechotrackandthemodeledresultsisobserved.[Work supportedby Officeof NavalTechnology.
]
3:03
DDD23.Double
scattering
fromtwoparallel
'rough
surfaces
using
the
facet-ensembleapproach.Henry F. Schreiner(Naval Ocean Research
and DevelopmentActivity, Code245, NSTL, MS 39529-5004)
Many featuresof the oceansurfaceand oceanbottomare generally
long crestedin shapeand can be approximatedby thin stripsor facets
placededgeto edge.Frequencyand time-domain(impulse) solutionsfor
diffractionand reflectionoff this kind of surfacehave beensuccessfully
modeled[W. A. KinneyandJ. G. Zornig,J. Acoust.Soc.Am. 77, 14031408(1985) ]. The introductionof a secondsurfaceof interactioncreates
a significantly
morecomplexproblem.Medwinand Childspresented
a
Huygenswaveletinterpretationfor doublediffractionoff a pair of rigid
wedgesor troughs[ H. Medwinet al., J. Acoust.Soc.Am. 72, 1005-1013
(1982) ]. This interpretation
is usedto constructa modelthatcomputes
thecomplexacousticpressure
afterscattering
off two parallelfacet-construtted surfaces.The effectson the correlationbetweentwo separated
receiversare presented
as functionsof surfaceroughness
and bottomtopographyin the frequencybandof 500-1000Hz. Also,comparisons
are
givenat differentseastatesof single-receiver
responses
from backscatter
off prominentbottom featuresfor a 3-kHz 100-mssignal.All results
quantifythe effectsof the roughness
featureson signaldegradation.
[Work supportedby Officeof Naval Technology.
]
114thMeeting:Acoustical
Societyof America
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