Quiz 6 - Source Filter theory + Vowels

Question 1

What is the source-filter theory (hint : filling resonances)

Answer 1

This theory has 2 stages
1. Generation of a sound source that has its own structure and shape
2. The resonances in the VT will filter and sort the properties that will be produced for speech

Question 2

What is the ‘source’ in the source-filter theory?

Answer 2

The glottal source –> the vocal folds

Question 3

What is the ‘filter’ in the source-filter theory?

Answer 3

The supra-laryngeal cavities (anything ABOVE vocal folds)

Question 4

the frequency at the vocal folds has a _______ energy

1. Upward
2. Downward

Answer 4

2. Downward

Question 5

what is PRAAT able to do with EEG tech?

Answer 5

Directly measure the activity of the vocal folds

Question 6

To crate source signals in PRAAT, what frequency do you need to be at for both points? and what about the range of points?

▶ New > Tiers > Create PitchTier…
▶ View & Edit > Add point at…: Time= 0.0 and Freq = ___
▶ View & Edit > Add point at…: Time= 0.5 and Freq = 100
▶ Synthesize > To PointProcess…
▶ select PointProcess object: Modify > Remove points between > put 0.25 and
0.30

A. 100;150; 0.30 and 0.25
B. 100;150; 0.25 and 0.30
C. 150;150; 0.25 and 0.30
D. 150;100; 0.25 and 0.30

Answer 6

D. 150;100; 0.25 and 0.30

Question 7

What is the formula for finding the frequency harmonics (think about F)

Answer 7

F0 x the # of harmonic you want to find
E.g. 150 x 3 = 450 Hz

Question 8

Can we calculate harmonics from a voiceless fricative (e.g., [f])?

A. Yes
B. No
C. Not sure

Answer 8

B. No
We can only calculate harmonics from PERIODICITY - that way we know that harmonics are also reliable!

Question 9

What is a band has a higher and lower cut-off

Answer 9

Pass band

Question 10

True or false : the bandpass’s cutoff is the same on both sides

Answer 10

True

Question 11

After making a recording, you now want to keep the frequencies from 200Hz and above. What kind would you use

a. Bandpass filter
b. low pass filter
c. highpass filter

Answer 11

c. highpass filter - low cutoff = 200Hz, higher part = infinite

Question 12

Our vocal tract acts as a series of _____ pass filters

Answer 12

band

Question 13

Explain the 3 steps for vocal tract band pass filter and what is the x and y

Answer 13

1. Acoustic source
2. Vocal tract filter
3. Output sound

Amplitude, frequency

Question 14

For input/output sound, the center frequencies of filters = _______, known as the ______

Answer 14

formants; vowels

Question 15

What is the formula for a resonance of a tube open at both ends

Answer 15

Xn = 2L/n

Question 16

True or false : a tube can have multiple resonant frequencies, but all get amplified

Answer 16

first part is true, but some get amplified and others get dampened

Question 17

A tube open on both ends = ___ wave length

Answer 17

1/2

Question 18

In the formula Xn= 2L/n, the 2L stands for ___

Answer 18

F0 - the fundamental frequency

Question 19

Whats the formula for a wavelength of a resonance in a tube that is open on one end and what is its maximal wavelength overall

Answer 19

Xn = 4L/n; 1/4

Question 20

Our vocal tract acts like a tube which is closed at one end in the ________ and open at the other, the ______

Answer 20

larynx; oral cavity/lips

Question 21

What is a standing wave?

Answer 21

Waves that get sustained and the characteristic patterns from the modes of vibration associated with RESONANCE

Question 22

An antinode is found at the ___ of a wave and a node is found at the _____

Answer 22

peak/valley; zero line

Question 23

T or F : standing waves in a tube open on both sides have a antinode on the zero line

Answer 23

F, antinodes can’t be on the zero line

Question 24

What is the formula for 1st, 2nd, and 3rd standing waves for a tube open on both sides

Answer 24

1. X1 = 2L
2. X2 = L – 2L/2
3. X3 = 2L/3

Question 25

T or F : even if a wave doesn't survive, it can still oscillate

Answer 25

F : a wave has to survive to oscillate; has to meet certain conditions

Question 26

What is the formula for finding wavelengths on one side

Answer 26

Xn = 4L/(2n-1) - you need an odd number

Question 27

We have a tube that is open on side A and closed on side B. Which of the waves will not "stand" in the tube? 1. a wave that has nodes on both sides 2. a wave that has antinodes on both sides 3. a wave that has a node on side A and an antinode on side B 4. a wave that has an antinode on side A and a node on side B

Answer 27

4. a wave that has an antinode on side A and a node on side B

Question 28

Formula for finding standing waves or resonant frequencies (2)

Answer 28

1. fn = 35000cm/s / Xn 2. fn = (2n-1)35000 cm/s / 4L

Question 29

When we make a schwa, what kind of tube do we have?

Answer 29

Single tube

Question 30

What are two ways we can model vowel production with tube models

Answer 30

1. Two-tube models 2. Helmholtz resonators

Question 31

What is a nomogram?

Answer 31

It is a diagram that represents the resonant frequency estimates from tube models

Question 32

Reminder : practice reading nomograms

Question 33

Where is the back cavity and the front cavity in a nomogram

Answer 33

back cavity is technically more on the right side and front cavity is on the left

Question 34

What do the lines in a nomogram represent?

Answer 34

Both for front and back cavity, the lines represent F1, F2 and f3

Question 35

What is a Helmholtz resonator? What does it look like?

Answer 35

the combination of the back cavity and a constriction (space between 2 tubes); looks like for example, a water bottle

Question 36

Where do we see the helmholtz resonator in a nomogram?

Answer 36

At the bottom of the nomogram, the first dotted line that shows up

Question 37

Which of the following statements are true for open-open tubes in acoustics? a. You do not need to know the volume of the tube to find the resonant frequencies b. They resonate at even multiples of the fundamental frequency. c. A tube of smaller radius will resonate a higher frequencies. d. They resonate at odd multiples of the fundamental frequency.

Answer 37

a. You do not need to know the volume of the tube to find the resonant frequencies b. They resonate at even multiples of the fundamental frequency.

Question 38

You are analyzing a speech recording of a speaker pronouncing vowels, and you are interested in isolating the frequency components to study fricatives like [s] and [ʃ], not the vowels. What type of filter would you apply to focus only on the fricative frequencies and above? a. Low-pass filter followed by high-pass filter b. Band-pass filter c. High-pass filter d. Low-pass filter

Answer 38

c. High-pass filter

Question 39

Mary has a tube that is 6 cm long. When she blew air over the top on one end while closing the other, she found that the lowest note that sustained in the tube had a frequency of 1400 Hz. What would be the frequency of the second standing wave for the tube? 700 Hz 4200 Hz 2800 Hz 2100 Hz

Answer 39

4200 Hz

Question 40

John has two tubes, A and B, of the same length. Tube A is open at both ends, while Tube B is closed at one end. Which of the following statements are true? (Select two correct answers.) a. Tube A will accommodate half of the wavelength of the first standing wave. b. The frequency of the first standing wave in Tube A will be half that of Tube B. c. Tube B will accommodate ¼ of the wavelength of the first standing wave. d. The frequency of the first standing wave in Tube A will be double that of Tube B.

Answer 40

Tube A will accommodate half of the wavelength of the first standing wave. Tube B will accommodate ¼ of the wavelength of the first standing wave.

Question 41

Which one is true about the boundary conditions in a closed-open tube? a. There is an antinode at the closed end and a node at the open end. b. There is a node at the closed end and an antinode at the open end. c. There are nodes at both the closed and open ends. d. There are antinodes at both the closed and open ends.

Answer 41

b. There is a node at the closed end and an antinode at the open end.

Question 42

Which one is true about the boundary conditions in a open-open tube? a. There is an antinode at the closed end and a node at the open end. b. There is a node at one open end and an antinode at the open end. c. There are nodes at both open ends. d. There are antinodes at both open ends.

Answer 42

d. There are antinodes at both open ends.

Question 43

Which of the following are true when you produce a sustained vowel like [ɔ:]? (Two correct answers.) a. The filter(s) your vocal tract is/are band-pass filters. b. The filter(s) your vocal tract is/are low-pass filters. c. Your supra-laryngeal cavity acts as a single filter. d. Your supra-laryngeal cavity acts like it has multiple filters in sequence.

Answer 43

a. The filter(s) your vocal tract is/are band-pass filters. d. Your supra-laryngeal cavity acts like it has multiple filters in sequence.