Acoustics Exam 4

Source

changing airflow by abduction and adduction of vocal folds

Periodic

a repeated pattern in cycles; pure tone —> simple harmonic motion & vowels

Aperiodic

noise; no repeated pattern; continuous = over a long duration /s/ or /sh/; transient = short duration /f/ or /t/

Resonance System

the vocal tract ad has a transfer function

Cavity

contains air molecules

Shape

the shape of the VT is important; this determines the cross-sectional area

Filter

the supraglottal vocal tract; size and shape of vocal tract

Microphone recording

receives both source and filter characteristics and we can see this on PRAAT

Phonation

back-and-forth motion of vocal folds caused by interaction of the tissue and air flow; air flow causes vocal fold vibration

Time domain

occurs in a series of time

Glottal Flow

air flowing between the vocal folds; transglottal flow

Fundamental Frequency

a parameter of source of sound; the lowest frequency that can be produced; the rate of vocal fold vibration; hertz (Hz)

Fundamental frequency: effect of age

childhood - adult we have a increase in vocal fold mass; increase mass = decrease fundamental frequency

Fundamental frequency: effect of sex

males have more vocal fold mass than women and children; increase mass = decrease fundamental frequency

Frequency (acoustics)/ pitch (perceptual) PHYSIOLOGY:

the number of opening/closing of the vocal folds per second; related to the mass and stiffness (tension); increase stiffness = increased fundamental frequency

Frequency (acoustics)/ pitch (perceptual) ACOUSTIC MEASURES:

measure frequency we look at the fundamental frequency

Intensity (Acoustic)/ Loudness (Perceptual) PHYSIOLOGY:

intensity related to subglottal pressure; the amplitude excursion is important; when the vocal folds are pushed apart (move further) we get more subglottal pressure and then more intensity

Intensity (Acoustic)/ Loudness (Perceptual) ACOUSTIC MEASURES:

Use 10log (Pi/Pr)

Vocal tract

the filter; the supraglottal tract (above the VF); air cavity that extends from the larynx to the lips; we care because in physiological changes it changes the air space and this leads to different vowels

Closed-open tube

vocal tract is similar to close-open tube acoustically; model of VT; the difference between the two is that you can change cross-sectional area w/ the VT but NOT closed-open (uniform vocal tract)

Resonance

frequency region that is amplified and related to the size/shape of VT

Fromant

same as resonance frequency; a measure resonance of the VT

Neutral Vocal Tract

F1 = 500 Hz

F2 = 1,5000 Hz

F3 = 2,500 Hz

Relationship between VT length and formant frequency

VT configuration yield different formant frequency patterns that eventually develops some rules that govern F1,F2, F3, etc.; when change mouth shape, it shifts formant frequency to higher or lower for specific vowel production

Pressure Distribution

Closed-End: max

Open-End: min

Velocity Distributions

Closed-End: min

Open-End: maxPhary

High Front Vowel /i/

Pharynx = wide ; Oral Cavity = narrow ; Oral Opening = lips unrounded

F1 = low F2 = high

High Back (rounded) Vowel /u/

Pharynx = neutral ; Oral Cavity = wide ; Oral Opening = lips rounded

F1 = low F2 = low

Low Back Vowel /a/

Pharynx = narrow ; Oral Cavity = open ; Oral Opening = wide oral opening

F1 = high F2 = low

Rule 1 (Tongue Height/F1)

inversely related to tongue height; as tongue goes up F1 goes down and vice versa

Rule 2 (Tongue Advancement/f2)

directly related to tongue advancement; as the tongue moves forward F2 goes up and vice versa

Rule 3 (VT lengthening)

all formants decrease with lengthening of the vocal tract; by raising the larynx; low pitch sounds = lower larynx; when we round our lips

Formant Trajectory

a change in the formant pattern that reflects changes in vocal tract shape