Resonance and Source-Filer Theory

Question 1

Describe the movement of sound waves in an air-filled container (acoustic resonator).

How does the acoustic resonator amplify sound? How does it filter sound?

Answer 1

Amplify frequencies that match a natural frequency of the container by constructive interference (amplification).

Frequencies that do not match the natural frequency will be attenuated due to destructive interference (attenuation).

Question 2

What properties are represented on the X axis and Y axis of a spectrogram? How is intensity/amplitude represented on a spectrogram?

Answer 2

X-axis: frequency
Y-axis: amplitude
Intensity is the color

Question 3

Shape of vocal tract

Answer 3

Filter

Question 4

Rate of vocal fold vibration

Answer 4

Source

Question 5

Formant

Answer 5

Filter

Question 6

Resonant frequencies

Answer 6

Filter

Question 7

Harmonics

Answer 7

Source

Question 8

Vocal pitch

Answer 8

Source

Question 9

Need to know that the resonant frequencies of the vocal tract (filter) do not depend on the fundamental frequency (F0) of the vocal source (source), and vice versa

Answer 9

Produce one vowel (filter) with varying pitch (source) - same filter, different source

Produce different vowels (filter) with same pitch (source) - different filters, same source

Question 10

Explain how the vocal tract filters the sound produced by vocal fold vibration to create distinct speech sounds. Use the following terms: resonant frequency(ies), harmonics, amplify, attenuate, variable resonator.

Answer 10

The vocal tract acts as a variable resonator that shapes sound by changing its shape and length. It filters the harmonics from the vocal fold vibrations by amplifying those closest to its resonant frequencies and attenuating others. This filtering creates the distinct speech sounds we hear.

Question 11

Explain why F1 is not the same as the fundamental frequency (F0).

Answer 11

F1 is determined by filter, while F0 is the source (vocal fold vibration)