Exam 3 Flashcards
Is the human voice perfectly periodic?
No. It’s semiperiodic; a perfectly periodic voice would sound like a machine to us.
Jitter
Variation in F0 from one cycle to the next
- The period of each cycle
Shimmer
Variation in amplitude from one cycle to the next
Chest register
- Singing vocal register
- Normal voice
Falsetto
- Singing or voice
- AKA loft
- Higher pitch
- Breathy, light, & airy
- Due to fast vocal vold vibration
Pulse/Vocal fry/Glottal fry/Creaky voice
Voice with very low F0 and creaky voice quality
Modal
Voice at normal, comfortable pitch used for talking
Open quotient
Proportion of time vocal volds are open during each glottal cycle
How voice quality types are differentiated
3 main phonation types in voiced speech
- Breathy
- Modal (Normal)
- Creaky
Hypo- vs. Hyperadduction
Hypoadduction: VFs adducted w/ insufficient medial compression
Hyperadduction: VFs adducted w/ excessive medial compression
- false VFs can start vibrating as well (harsh voice/ventricular phonation)
Aphonia
Complete absence of voice
Dysphonia
Any kind of vocal dysfunction resulting in a deviant-sounding voice
Maximum phonation time for adults & children
Adults: 15-25 sec
Children: at least 10 sec
Minimum-maximum intensity at varios F0 levels graph
Football-shaped
Breathy voice production
Incomplete closure of VFs causes air to leak during phonation
- inefficient, so intensity range is reduced
- more air used than normal phonation
More common in females & increases w/ age
Breathy voice: acoustic characteristics
- Less periodic
- More high-frequency noise (above 5 kHz)
- Loss of energy between 2-5 kHz
Rough/hoarse voice characteristics
Rough: sounds raspy & low pitched due to aperiodic VF vibration
- Hoarse voice = breathy + rough
Rough/hoarse voice: acoustic characteristics
- Larger amt. of spectral noise at lower (100-2600 Hz) frequencies
- Decreased periodic VF vibration
Harmonics-to-Noise Ratio
Another way to measure how periodic a voice is
Compares amplitude of harmonics to amplitude of noise in signal
- Mostly periodic voices have high HNR (20 dB + is normal)
- More noisy/less periodic voices have low HNR
Vocal tract differences from Homo erectus to Homo sapiens
Larynx is now much lower. We can produce more sounds now, but we also have an increased danger of choking.
Vocal tract
Pharynx, oral & nasal cavities
- Can change shape at tongue, lips, jaw & velum
- Allows for speech sound generation
Formants
The resonant frequencies of the vocal tract
The vocal tract is a _______-wave resonator.
quarter
- Closed end = glottis
- Open end = lips
Source-Filter Theory
The vocal tract acts as an acoustic filter, which modifies the sound produced by a sound source (VF vibration, turbulent noise, or a combination of the two)
- Source is independent of filter (F0 doesn’t affect our perception of vowels)
How does an acoustic filter work?
Filters out certain frequencies of complex sounds while allowing other frequencies to pass through
- Complex sounds are composed of sine waves of more than one frequency
- A filter reduces/increases the amplitude of one or more component sine waves
Characteristics of the sound produced at the glottis
- A complex periodic wave
- Has an infinite number of sinusoidal components (harmonics)
- All are integer multiples of F0
- Harmonic amplitude decreases as frequency increases
- Harmonics above 10,000 Hz do not make a big contribution to speech production
Harmonics
Component sinusoids of a complex periodic wave
- Integer multiples of F0
- Identified by numbers from lowest to highest frequency
- F0 = H1
What factors affect sound quality?
Which harmonics are present
What the amplitude of each harmonic is
- determined by the SLVT
__________ determines which harmonics are filtered out by the SLVT.
Wavelength
What does it mean for a harmonic to “fit” the vocal tract?
Harmonics differ in their wavelength. Different harmonics will “fit” into the resonating chambers.
- Harmonics whose wavelengths best fit into a chamber will gain amplitude (resonate)
- These are formants
- Those that do not fit will lose amplitude & be filtered out.
In a neutral-shaped vocal tract, a sinusoid will fit if there is a _______________ at the glottis and a ____________ at the lips.
pressure maximum; zero crossing
What is a standing wave?
A wave with a higher amplitude than the original sinusoid that is formed when a sinusoid’s wavelength fits the vocal tract
- Occurs from the echo (reflection) of the sound in the vocal tract
Resonant sounds are characterized by the relationship among the first __ formants
3
Formants on spectrograms vs. spectra
Spectrogram: frequency is on the Y axis
Spectrum: frequency is on the X axis
Formant frequencies are ___________ of the rate of vocal fold vibration
independent
What 2 factors determine formant frequencies?
- The length of the speaker’s vocal tract
- The size & shape of the vocal tract cavities
Vocal tract shape and F1
Influenced by the pharynx
- A constriction in the oral cavity (high vowels) results in a large pharynx and a low F1
- A constriction in the pharynx (low vowels) results in a small pharynx and a high F1
Vocal tract shape and F2
Influenced by the oral cavity
- A constriction at the back of the oral cavity (back vowels) results in a large oral cavity and a low F2
- A constriction at the front of the oral cavity (front vowels) results in a small oral cavity and a high F2
What effect does lip rounding have on formants?
Lowers frequencies of all formants because it lengthens the vocal tract.
/w/ and /j/ are like extreme versions of which two vowels?
/u/ and /i/
Why do liquids and glides have less amplitude than vowels?
As the vocal tract becomes more constricted, the amplitude drops.
Formant values for /l/ are sometimes very similar to those for which sound?
/o/
What are “zeroes,” “anti-formants” or “anti-resonances”?
Reduce the amplitude of nearby formants. Present in nasal and liquid sounds.
/l/ acoustics
Lateral airflow produces zeroes/anti-resonances
- On a spectrogram, formants above F1 often vanish
The most important acoustic characteristic of /r/ is a low ___ frequency
F3 (extremely unusual)
3 constrictions in English /r/
- lips
- palate
- pharynx
Are 3 antinodes of F3
Nasal articulation/acoustics
Air flows through the nasal cavity, which is large compared to the pharynx & oral cavity
- Has a very low first formant (the “nasal formant”)
