Artificial Ear Dilemma
Historical
IEC 60318
IEC 60711
Anatomical variations
Combined coupler and pinna
Closed-coupler testing
Free-field testing
Zwislocki to IEC correction
G.R.A.S. Sound &Vibration A/S
Historical
French Artificial
Ear made by
CNET
G.R.A.S. Sound &Vibration A/S
Historical
Swiss Artificial Ear
made by the Swiss
P.T.T.
G.R.A.S. Sound &Vibration A/S
Historical
NBS 9-A
Earphone Coupler
G.R.A.S. Sound &Vibration A/S
IEC 60318
The IEC 60318-1
ear. The
impedance and
lumped parameter
electrical network
is shown in the
IEC 60318-1
standard.
G.R.A.S. Sound &Vibration A/S
IEC 60318
Frequency response
obtained by a ½”
condenser microphone
receiver and transmitter
mounted concentrically
at the top and bottom of
the variously shaped
coupler volumes. Valid
for the range 500-20000
Hz. All coupler
dimensions are given in
millimeters. Vertical
scale 2dB per line, 50dB
full scale.
G.R.A.S. Sound &Vibration A/S
IEC 60318
Detailed
measurements to
determine the
optimum
dimensions for the
best possible
linearity over the
widest frequency
range. 10dB full
scale. 0.4 dB per
line.
G.R.A.S. Sound &Vibration A/S
IEC 60711
G.R.A.S.
RA0045
occluded ear
simulator as
used in
KEMAR
G.R.A.S. Sound &Vibration A/S
Anatomical variations
Ear moulds from
same person. Right
and left ears. The
width at the most
narrow passage is
6mm for the left
ear and 9.6mm for
the right ear.
G.R.A.S. Sound &Vibration A/S
Combined coupler and pinna
Type 43AG
Ear and Cheek
Simulator with
IEC 60711
Coupler
G.R.A.S. Sound &Vibration A/S
Closed-coupler testing
Telephone Test Head
Type 45AA showing:
Left; fitted with a
G.R.A.S. Mouth
Simulator & IEC 60318
Ear Simulator Type
43AD.
Right; computer
rendering outlining its
chief components
G.R.A.S. Sound &Vibration A/S
Closed-coupler testing
Speaking Position
Recommendation
LRGP
ITU-T Rec. P76
AEN
ITU-T Rec. P76
HATS
ITU-T P58
REF
OREM A
Speaking positions according to current
recommendations
G.R.A.S. Sound &Vibration A/S
Closed-coupler testing
Showing where the
Lip-ring of the
Mouth Simulator
(Type 44AA or
44AB) should be
for both AEN and
REF positions. The
angular distances of
39° and 13° (in that
order) will move
the handset from
the AEN position
to the LRGP
G.R.A.S. Sound &Vibration A/S
Free-field testing
KEMAR with
positioning
device
G.R.A.S. Sound &Vibration A/S
Free-field testing
KEMAR with
reference
microphone for
linearization
G.R.A.S. Sound &Vibration A/S
Free-field testing
Auricle
Measures used
in KEMAR
G.R.A.S. Sound &Vibration A/S
Free-field testing
Mean values of
frequencies of pressure
maxima and minima at
the open ear canal
entrance for 12 male
and female subjects;
sound incidence from
90; loudspeaker source
at 1m.
Equivalent lengths
based on c=354 m/s
for l1 and l3, c=349.5
for L1 and L3.
G.R.A.S. Sound &Vibration A/S
Free-field testing
Ear canal entrance sound
pressure, 12 females (above),
12 males (below), sound source
at 90º azimuth angle, 1m.
Free field is the reference
pressure condition
G.R.A.S. Sound &Vibration A/S
Free-field testing
KEMAR Ear drum
sound pressure for a free
sound field with source
azimuth angles of 0°,
90°, 180°, and 270°.
G.R.A.S. Sound &Vibration A/S
Zwislocki to IEC correction
15 IEC Modulus
values of the acoustic
transfer impedance
function from IEC
711-1982 relative to
the ANSI modulus
values of the acoustic
transfer impedance
function.
G.R.A.S. Sound &Vibration A/S