Y-
Lo
i p f I e- rt-e-n r aide o A -*t -
LD f\ -e
Y
Oi I * I '
2.2
_
2.0
_
(n
U.
L8 _
0
N 1.6
_ o kg
* NULL
1.4
B.2
fF
12 z
1.0
-
OR
0.2
LU.
!
*I, le
T 1
0.5
, l
FREQUENCY OF Fl (KCPS)
0.8
Figure 10.8 Values of FI and F2 at the midpoint of the vowel for eight vowels, plotted to demonstrate the effect of place of articulation of the consonantal context. The contexs are divided into three groups: velars (open squares); postdentals (open triangles); labials (open circles). Values for vowels in the null environment (averages of formant frequencies for vowels in isolation and in context /h-d/) are included for comparison (black dots). Points represent average values for three talkers. (From K. N. Stevens and House, 1963.)
--------------- ----

6.541J Handout
i4 sp ee': sDM
es
lI
E a
0
I II III
Articulotory parameter
Figure 1. Schematization of a relation showing a change in a relevant acoustic parameter as an articulatory parameter specifying some aspect of the state or configuration of the speech-production system is manipulated. The curve can be divided into the regions I, II, and III as discussed in the text. The same form of the function can occur when an auditory parameter is plotted on the ordinate and an acoustic parameter is plotted on the abscissa.
2 y-
I* · -I
0-4 0-5
(a)
Co) i As o o o 20
.
o0.2
A g = 0.2 cm 2 0-3
-6 c 10
(A)
0
0 0.1 0.2 0.3 0.4
Area of supraglottal constriction (cm 2 )
0.5 b)
(B)
"Resting" area of suproglottol constriction (cm
2
)
Figure 19. (a) Calculated levels of the turbulence noise sources at the supraglottal and glottal (dashed line) constrictions as a function of the area of the supraglottal constriction. The area of the glottal constriction is fixed at
0.2 cm
2
. (b) Same as (a), except that the size of the constriction is modified by glottal constriction would assume before application of the subglottal pressure
(from Stevens, 1987).
0
-0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5
"Resting" area of supraglottal constriction (cm 2 )
(a)
Constriction for Fricatives
Calculated levels of the turbulence noise sources at the supraglottal and glottal (dashed line) constrictions
as a function of the area of the supraglottal constriction. The area of the glottal constriction is fixed at 0.2 cm 2 .
(b) Same as (a), except that the size of the constriction is modified by the presence of the intraoral pressure.
The abscissa is the area that the supraglottal constriction would assume before application of the subglottal
pressure.
-~------

(A)
A
1
A c
A
2
L c
L
2
A
1
L
1
(B) A
2
L
1
L
2
Examples of two configurations of acoustic tubes for which there is relatively little acoustic coupling between the left-hand portion, of length L
1,
and the right-hand portion of L
2
.
4
3
2
A
1
= 0.5 cm 2
A
1
= 0
1
0
2
Low back vowel
4 6 8 10 12
Length of back cavity, L
1
(cm)
14
Frequencies of first four natural frequencies for configuration of first figure on left, as the length L of the back cavity is manipulated. The total length L and the cross-sectional area A
2
= 3 cm 2 case where A << A
2
, and the solid line is for A impedance is assumed to be zero.
1
1
+ L
2
= 16 cm,
. The long-dashed line corresponds to the
= 0.5 cm 2 . The radiation
4
3
A c
= 0.5 cm 2
2
0.2
0
1
0
0 2 4 6 8
Length of back cavity, L
10
1
(cm)
12 14
Frequencies of first four natural frequencies for configuration of figure (a) on top left, as the length L
0.5 cm 2
1
of the back cavity is manipulated. The total length constriction length L c = 2 cm, and the cross-sectional areas impedance is assumed to be zero.
A
L
1
+ L c +
1
and A
The long-dashed lines (labeled 0) correspond to the case where A
2 c <<
A
L
2
= 16 cm, the
are 3 cm 2 .
1
, in which case the lowest natural frequency is zero. The solid and short-dashed lines are for A
, respectively. The tube is assumed to be hard-walled, and the radiation c = 0.2 and
7
6
5
4
3
2
F6
F5
F4
F3
1
1 2
L f
3
(cm)
4
Different Places of Articulation for Obstruents
5
Calculated natural frequencies for a model of vocal tract with a narrow constriction as the length L f
of the front cavity changes from 1 to 5 cm. The dashed lines give the frequencies of the back- and front-cavity resonances assuming no acoustic coupling between these cavities. The solid lines are the resonances if coupling is taken into account.