Quiz 6 - Source Filter theory + Vowels Flashcards
What is the source-filter theory (hint : filling resonances)
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
What is the ‘source’ in the source-filter theory?
The glottal source –> the vocal folds
What is the ‘filter’ in the source-filter theory?
The supra-laryngeal cavities (anything ABOVE vocal folds)
the frequency at the vocal folds has a _______ energy
- Upward
- Downward
- Downward
what is PRAAT able to do with EEG tech?
Directly measure the activity of the vocal folds
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
D. 150;100; 0.25 and 0.30
What is the formula for finding the frequency harmonics (think about F)
F0 x the # of harmonic you want to find
E.g. 150 x 3 = 450 Hz
Can we calculate harmonics from a voiceless fricative (e.g., [f])?
A. Yes
B. No
C. Not sure
B. No
We can only calculate harmonics from PERIODICITY - that way we know that harmonics are also reliable!
What is a band has a higher and lower cut-off
Pass band
True or false : the bandpass’s cutoff is the same on both sides
True
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
c. highpass filter - low cutoff = 200Hz, higher part = infinite
Our vocal tract acts as a series of _____ pass filters
band
Explain the 3 steps for vocal tract band pass filter and what is the x and y
- Acoustic source
- Vocal tract filter
- Output sound
Amplitude, frequency
For input/output sound, the center frequencies of filters = _______, known as the ______
formants; vowels
What is the formula for a resonance of a tube open at both ends
Xn = 2L/n
True or false : a tube can have multiple resonant frequencies, but all get amplified
first part is true, but some get amplified and others get dampened
A tube open on both ends = ___ wave length
1/2
In the formula Xn= 2L/n, the 2L stands for ___
F0 - the fundamental frequency
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
Xn = 4L/n; 1/4
Our vocal tract acts like a tube which is closed at one end in the ________ and open at the other, the ______
larynx; oral cavity/lips
What is a standing wave?
Waves that get sustained and the characteristic patterns from the modes of vibration associated with RESONANCE
An antinode is found at the ___ of a wave and a node is found at the _____
peak/valley; zero line
T or F : standing waves in a tube open on both sides have a antinode on the zero line
F, antinodes can’t be on the zero line
What is the formula for 1st, 2nd, and 3rd standing waves for a tube open on both sides
- X1 = 2L
- X2 = L – 2L/2
- X3 = 2L/3
T or F : even if a wave doesn’t survive, it can still oscillate
F : a wave has to survive to oscillate; has to meet certain conditions
What is the formula for finding wavelengths on one side
Xn = 4L/(2n-1) - you need an odd number
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
- a wave that has an antinode on side A and a node on side B
Formula for finding standing waves or resonant frequencies (2)
- fn = 35000cm/s / Xn
- fn = (2n-1)35000 cm/s / 4L
When we make a schwa, what kind of tube do we have?
Single tube
What are two ways we can model vowel production with tube models
- Two-tube models
- Helmholtz resonators
What is a nomogram?
It is a diagram that represents the resonant frequency estimates from tube models
Reminder : practice reading nomograms
Where is the back cavity and the front cavity in a nomogram
back cavity is technically more on the right side and front cavity is on the left
What do the lines in a nomogram represent?
Both for front and back cavity, the lines represent F1, F2 and f3
What is a Helmholtz resonator? What does it look like?
the combination of the back cavity and a constriction (space between 2 tubes); looks like for example, a water bottle
Where do we see the helmholtz resonator in a nomogram?
At the bottom of the nomogram, the first dotted line that shows up
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.
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.
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
c. High-pass filter
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
4200 Hz
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.
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.
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.
b. There is a node at the closed end and an antinode at the open end.
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.
d. There are antinodes at both open ends.
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.
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.
