Vowel Acoustics

Question 1

where does our vocal tract close on the one side

Answer 1

larynx

Question 2

what makes a standing wave a standing wave

Answer 2

it is a wave that will sustain

Question 3

what is a resonating chamber

Answer 3

a tube or our throat

Question 4

what allows waves to “stand” in a resonating chamber

Answer 4

the wave must abide to the boundry condition

Question 5

what are the rules of a boundary condition

Answer 5

• if a tube allows a node at a certain end, a sustained wave must have a node of that end
• if a tube allows a antinode at a certain end a sustained wave must have a antinode.
• other waves will simple die

Question 6

pros and cons of a singel tube model

Answer 6

• is the easiest way to wrap your mind about sources and filters
• only acceptable for modeling schwa-like productions because there is no constrictions

Question 7

the first resonant frequency is the lowest or highest?

Answer 7

Lowest

Question 8

what type of vowel uses a Helmholtz resonator?

Answer 8

some vowels, especially high ones.

Question 9

what is a Helmholtz resonator?

Answer 9

the constriction tube and back tube together created a specail chamber, this type of chamber is termed as a Helmholtz resonator.

Question 10

what is a harmonic?

Answer 10

• all waves created by the “source” e.g. vibrating vocal folds.
• lowest frequency F0 or H1
• H2 = 2 x H1

Question 11

what is a formant?

Answer 11

• all standing waves in the “filter” e.g. vocal tract/tube
• lowest standing wave is F1
• F1 x 3 = F2. ////. F1 x 5 = F3

Question 12

what does F1 and F2 represent?

Answer 12

F1 indicates tongue height; F2 indicates tongue backness.

Question 13

What is the relationship between F1 and F2?

Answer 13

• a higher tongue position doesn’t directly lower the F1, we saw that the low F1 is actually the magic of Helmholtz resonator.
• or a lower tongue position doesn’t directly raise the F1.

Question 14

What kind of vowels use Helmholtz resonator and what kind use two tubes.

Answer 14

HH= high vowels
2tube= low vowels

Question 15

what is perturbation theory?

Answer 15

it is another way of understanding the acoustic consequences of events in the vocal tract

Question 16

Contriction or pressure near the antinode … the frequency?

Answer 16

DECREASES

Question 17

Constriction or pressure near the node … the frequency?

Answer 17

INCREASES

Question 18

what are 3 common patterns in perturbation models?

Answer 18

• all standing waves have anti-node at the lips end, constricting the lips lowers all formants.
• F1 has a node close to pharynx, a constriction in the pharynx raises F1
• F2 has a node near the alveolar ridge, alveolar restrictions raise F2.