FINAL EXAM Flashcards
What is a filter?
- A device that allows some things to go through but not others
- Vocal Tract can act as a filter
-Some frequencies may pass through / others may not
What are the sound sources that we may use when speaking?
- Phonation
- Stop plosion
- Frication
What is the period of an oscillation?
Phonation:
- Period= Time to complete one cycle/ For speech, one glottal cycle
What is the frequency of an oscillation?
Phonation:
- Frequency= the inverse of a period
- f=1/T
Define the fundamental frequency and harmonics
Fourier analysis:
- Lowest will be the fundamental frequency (F0)
* AKA first harmonic (H1)
- Harmonics are whole number multiples of the F0 ( Fundamental frequency)
*H2= 2 x F0, H3= 3x F0, etc.
What happens to the energy of each subsequent harmonic produced?
- With each harmonic, there is a relative reduction in energy ( amplitude)
- This happens at the level of the larynx
12 DB dropoff with each harmonic( Decrease in energy/intensity)
What does the vocal tract model?
-Models a tube closed at one end that contains different frequencies traveling
- “Closed at the level of the larynx
What is the source filter theory?
- Contains source spectrum, filter function, an output energy
- Shows frequency in the larynx
- The higher the frequency, the further apart harmonies will be
- Can calculate the relative amplitude by taking the source and multiplying by the filter function
- regions of high energy are known as formants
-The First 3 formants are important for acoustic and perceptual specification
Vocal Tract: what is damping and where does it take place?
- Occurs when the resonant frequency of a nearby structure absorbs energy from the acoustic signal
- Will get more energy absorption when connecting other tubes to the vocal tract
- VP port is open so the nasal cavity is coupled to the oral cavity (Creates another “tube” and will be absorbed)
What happens when you change the shape of the vocal tract?
- Each tube has its own form (resonance)
- Can make different shape tubes
What happens when the sound sources for vowels are filtered?
- Travels through the vocal tract
- some harmonics are amplified
- some are attenuated
What are formants?
- A spectrum that has peaks at the resonant frequencies of the oral cavity
- Changes in the shape of this oral cavity change the frequencies of the formats
- About 18 that are within limits
- F1 can vary from 300 to 1000Hz
- F2 can vary from around 1000 to 300 Hz
What is F1 and F2?
F1= Lowest one, below 1000
F2= Always between 1000-3000Hz
- They both vary with height and placement
What does F2 represent?
- Vowel front/backness
- Lower F2
What does F1 represent?
- ## Vowel height low/high
A high back vowel will have a ____ F1 and ___ Low F2
Low F1 and Low F2
F1 Lows and Highs?
Lowest for closed vowels
Higher for open vowels
True/False: The formant pattern provides a listener w/ information about the positions and movements of the tongue, jaw, and lips
True!
What is Stevens and House rules?
- F1 lowers as tongue height increases
- More dramatic for front vowels than back vowls - F2 increases as the tongue moves forward
- F1 also decreases when the tongue moves forward - All formats decrease with lip rounding
- Particular true for F2
How do consonants differ from vowels?
Vowels:
- Can model the vocal tract as a single tube ( Watch Pink Trombone Video)
From Glottis ti lips
- Periodic Sound source–> Sound source repetition
Consonants:
-Vocal Tract configurations for some sounds can not be molded as a single tube–> b/c of VP port being open
- Sound Sources are aperiodic ( Frequences together)
* this means that they are not periodic/Not repeated*
What are the Coupled Resonators? AKA Shunt Resonators
Nasals
Laterals
Others
What are obstruents and Coupled resonators?
- Sounds where the sound source produced between two resonating cavities
- We make caviies by bringing articulators together
What are the sound sources that are generated between two resonating cavities?
- Front Cavity (from constriction to lips
- Back Cavity( From constriction to glottis)
What happens to the sound sources in the back cavity
- Sound in the back cavity is trapped, generating antiresonance
- Trap some frequencies /harmonics
How can the frication sound source be generated?
-Frication is the only sound source for voiceless fricatives
- Frication superimposed on phonation when fricatives are voiced
- Air passes through the constriction, the speed increases
* Air flows out as a jest surrounded by areas of rotating, randomly moving air molecules known as turbulence; Friction source
How is the sound source filtered via resonance and antiresonance?
Front Cavity will shape the resonance:
- Front cavity becomes smaller=resonace becomes higher in frequency/resonance has broad bandwidths ( lets lots of frequency pass)
Back is closed so will create antiresonance:
- As the back cavity becomes smaller, the antiresonace becomes higher in frequency( higher in pitch)
what are the two cavities that divide the vocal tract?
Front and back cavity
How does sound radiate in both directions?
To front and out the mouth
to the back and towards the glottis
which fricative would have the highest frequency resonance?
“Sh”—>has front cavity
Why do vocal stops not have aspiration?
The vocal folds are already abducted
What are the different components that create the sound source for stops
Stop production requires different components:
- Closure: puts articulators together
- Release(burst): puff of air
- Frication: When producing a stop
- Aspiration (voiceless stops only): additionally you have aspiration
What is the Voice onset time(VOT)?
- Release+frication+aspiration(voiceless): bringing together vocal folds when you have a little bit of time–>vocal folds cant be together for a voiceless stop
- Release+ frication ( voiced)
How do acoustic events line up with aerodynamics during fricative production?
- spike of airflow for the release
- followed by turbulent airflow(frication)
- caused by narrow constriction as the articulators move apart
- short duration
-Opening of fricatives=opening of articulators - For voiceless stops, there is aspiration
- caused by turbulent airflow at the glottis
- vocal folds abducting to begin voicing for the subsequent vowel
- 10-30 ms in duration
Why is the /p/flatter in a wavelength ?
No front cavity! /p/ is a label sound
* look at the slide 51*
What does the aspiration indicate in VOT?
Indicates that it is a voiceless stop
unaspirated vs aspirated plosives
Look at slide 53
What are affricates?
Affricates= stops + fricatives
Frication portion of the stop is prolonged
Slowly released stops
