2.06 - Transfer Function of the Vocal Tract Flashcards
The resonator (______) is ______.
Filter
Variable
The sound source can be ______, ______, or ______.
Periodic (voicing)
Aperiodic (noise)
Both
Resonance is the ______ to an ______.
Vibratory Response
Applied Force
A resonator is set into forced vibration by ______.
Another vibration
Resonators do not initiate the _______.
Sound energy
The vocal tracts acts like a ______. The body of air resonates _______ that has frequencies matching the natural ________ of volume of air.
Resonator
In response to sound
Resonant frequencies
Sound Sources have both ______ and _______.
Harmonics
Fundamental frequencies
Formants show up on spectrograms as _______. These are the _______.
Bands
Resonance frequencies
The resonance characteristics of the vocal tract (and the ear canal) can be roughly modeled after a uniformly shaped ______________.
Tube open at one end.
What four things do resonances in an tube depend on?
Are the ends of the tube are open or closed?
How long is the tube?
How is the tube shaped?
How large are the opening on the tube?
What is the typical speed of sound in air?
34,400 cm/s
How do we calculate the resonances of a uniform tube open at one end?
(twice the integer minus one) times (34,4000 cm/s divided by four times the length of the tube)
F = (2n-1)(c/4l)
How do we abbreviate Resonance?
F
How do we abbreviate length?
l
How do we abbreviate integers? What are they?
n
__ Resonance (1=first resonance, 2=second resonance, etc.)
What does “c” stand for?
The speed of sound
Normally 34,400 cm/s
What does shaping the vocal tract differently accomplish?
Changes the peaks in resonance
The typical male vocal tract is _____ cm long.
17.5
The typical female vocal tract is ______ cm long.
14.5
Are female vocal tracts just shrunken version of male vocal tracts?
No. They are smaller and shaped differently
The typical glottal source for vowels is ______.
Voiced
Can noise (hiss) excitation use the vocal tract to be resonated?
Yes
Harmonics ______ as they increase in frequency.
Decrease
When f0 changes, the spacing between the harmonics ______.
Changes
The vocal tract acts as a _____ resonator.
Variable
Altering cavity size results in different ______ producing a different _____.
Resonant frequencies
Vowel
Vowels have around _____ resonance frequencies/formants
7
What is the Lack of Invariance problem?
That we recognize speech via acoustic signals that are inconsistant
The glottal source is filtered according to the frequency response of the _________.
Vocal tract
If the glottal source is voiced, the harmonics of the glottal source at or near the spectral peaks of the ________ are resonated, while those distant from the spectral peaks _______ and become ________.
Transfer function of the vocal tract
Lose energy
Attenuated
The resonator works the same way if the source is _________, _______, or if _______.
Periodic (voiced)
Aperiodic (whisper)
f0 changes
Despite source changes (periodic vs. aperiodic or f0 changes), the resonances ______.
Remain the same
What two things most affect resonance frequencies?
The length of the pipe
The cross-sectional area of the pipe as a function of length
The radiated sound spreads in ______ as it leaves the mouth and the energy is ______ in lower frequencies. By how much?
All directions
Reduced
6 dB per octave
Why do motor disorders of the tongue create unintelligiblity?
Because you can’t change the shape
A good ventriloquist or impersonator can intuit how to ______ to match someone else’s
Change their vocal tract
What is the difference between Harmonics and Resonances?
Resonances are created when the source/signal’s harmonic structure is similar to the spectral peaks of the filter. When they are dissimilar they are attenuated.
A spectrogram shows tongue changes in the _______.
Formants
In speech, your mouth’s job is to ________.
Change the shape to make different sounds
Narrowband spectrograms show the _______. Wideband spectrograms show the _______.
Harmonics
Formants
