CSD 315s Quiz 3

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Terms in this set (...)

What is the process for production of sound?
Lungs to larynx to vocal tract to acoustic speech signals
What happens at the lungs?
generation of airstream
What happens at the larynx?
modulation of airstream
What happens at the vocal tract?
sound-shaping of airstream
What does airflow look like at the lungs?
a STEADY pulmonic egressive airstream
What does airflow look like at the larynx?
volume velocity pulses
What does airflow look like at the vocal tract?
sound pressure waveform of speech
What is happening when you see the air pressure go up suddenly on a waveform?
The air molecules are coming closer together
What is the laryngeal buzz?
burst of air in the larynx - sound but NOT speech
What does the fact that the cycles of both the volume velocity pulses and the sound pressure waveform of speech are the SAME show us?
That the laryngeal buzz shapes vowel sound
What are the sound waves in the air?
wave motion
What is produced by wave motion?
vibration of air molecules
Is vibratory motion the same as wave motion?
NO
What are the two properties needed for vibration?
Mass (air molecules) and elasticity (air itself)
What are the 5 measurable characteristics of vibratory motion?
Displacement, Amplitude, Frequency, Period, Phrase
What is displacement?
the distance from rest at any time in the circle
What is amplitude?
maximum displacement (+ and -)
What is frequency?
# of cycles per sec, Hz
What is period?
time taken to complete one cycle (msec, sec)
What is phase?
relative timing of vibration in relation to another (degrees)
Formula for frequency
F = 1/T
Formula for period
T = 1/F
How do you convert from msec to sec?
move decimal point 3 places to LEFT
Why is there no sound in a vacuum?
You need mass (air molecules) to carry vibrations
Displacement
distance from rest at any time during a vibration cycle
A sine wave is
vibration, simple, one frequency
Pressure
the amount of force acting over a unit area of surface (cm^2); unit = dyne/cm^2 which is converted to decibel measure
intensity
the power transmitted along the sound wave per unit area (cm^2); measured in units of watts/cm^2 which is converted to a decibel level
fundamental frequency (of vibrating system)
the lowest natural frequency of vibration; the frequency of repetition of a complex wave per second; the highest common denominator of component frequencies making up the complex wave; for voice = rate of vibration of vocal folds.
harmonic
a whole number multiple of the fundamental frequency (fo); an overtone of the voice fundamental
resonance
the phenomenon whereby one body, which has a natural vibration rare at a specific frequency will build up vibrations with a comparatively large amplitude when it is put into vibration by another object vibrating at a similar frequency. Illustrated by highest amplitude areas of a tuning or frequency response curve; in speech = formants of a vowel. ex: shattering of glass to voice; swaying of bridge in wind
compression
the movement of air particles closer together than normal equilibrium position which causes an increase in air pressure at those points; regions of compression called crests or peaks of a sound wave; have largest amplitudes in + direction
rarefaction
when air particles move further apart than their normal resting equilibrium position (0)l a decrease in pressure occurs at this point. regions of rarefied air known as troughs or valleys & have largest amplitude in negative direction of the cycle
propagation of sound
speed of sound (velocity of sound travel in air); the rate at which sound energy/wave travels thru the medium of air: constants = 1130 feet/sec; 3400 cm/sec, 770 mph
wave length
the distance the wave travels in one cycle of vibration; wave length = velocity of sound/frequency; the distance from crest/trough to next crest/trough = one wavelength; high frequency sound have small wavelengths & low frequency sounds have large wavelengths. measures (usually) in cm or feet.
periodic wave
repetitions of same basic vibration pattern for each cycle; vowel sounds are classic periodic waves b/c VF vibrate same pattern for vowel sound; harmonic overtones comprise components of such sound waves, which characteristic areas of resonance , known as the formats for each vowel
aperiodic wave
random fluctuations of sound pressure (=noise); no repeating vibration cycle, as molecular vibration is random.
spectrum
specification of the frequencies and corresponding amplitudes of all components of a complex sound; if the complex sound is periodic, the frequencies are harmonically related; if aperiodic, the components are all sinusoidal frequencies making up complex sound; line spectra & continuous spectra exist
fourier analysis
mathematical reduction of any complex wave into sinusoidal components comprising that wave, this algorithm is basis of sound spectrograph, which shows frequencies & amplitudes of all component sounds making up a complex speech sound
sine wave as uniform circular motion
uniform circular motion -> linear projection -> displacement over time
Each compression is followed by what?
a rarefaction
What is the top of a wave called?
Crest, in speech compression
What is the bottom of a wave called?
Trough, in speech rarefraction
What is velocity?
speed of sound; the speed at which vibrations propagate thru medium (air); this is a constant
What are the constant velocity measures?
1130 ft/sec, 34000 cm/sec, 770 mph
The faster the velocity is, the __ the wavelength is
shorter
Formula for velocity
frequency x wavelength
formula for wavelength
velocity/frequency
formula for frequency
velocity/wavelength
Every sound travels of distance of 1130 ft/sec in one second (T/F)
True, speed of sound!
What does resonance do?
makes a laryngeal buzz into a vowel
What must happen for resonance to occur?
frequencies match
What are free vibrations?
they don't have force
Example of forced vibrations
speech
Formants come from ____
resonance
What did Lieberman think the cause of stress is?
increase in Psg (16-20Hz increase in F0 for every 1 cmH20 increase in Psg signal)
What did Ohala think the cause of stress is?
the laryngeal system. F0 is increased, controlled by muscular contraction of cricothyroid muscles which elongate & increase tension of VF
What did Ohman think the cause of stress is?
increase in Psg, laryngeal system, and even other things such as articulatory channels
Who did a study to discover the truth about what causes stress?
Netsell
What did Netsell's study consist of?
EMGs of cricothyroid (laryngeal activity) and orbicularis oris (labial articulatory) and measurement of Psg

"A papa does" - min, mod, and max stress varied with 1-4, results listened and voted on for best
What did Netsell's study show?
larynx is the most sensitive, active during min stress. then psg. but larynx, psg, and lips are all active during max stress. so everyone was right.
What is stress?
emphasis on a syllable
What creates stress?
louder, longer, higher pitch

higher F0 is most important because it's always there
What do suprasegmentals show?
melody of voice/semantic gist
The independence of suprasegmentals can be shown by
stress placement
Stress placement changes a word's grammatical category
True
If there is stress on the first syllable the word is a
noun
If there is stress on the second syllable the word is a
verb
Intonation definition
the perceptual correlate of the time varying course of the F0 over the extent of a phrase/sentence
Questions end in __ intonation
rising
Juncture
pauses between certain words
What is the importance of juncture?
emphasizes stress & gives semantic gist
The acoustic existence of approximants/glides is based on
the speed of articulators

they are made dynamically
[j] - "yellow"
palatal semivowel
[w] - "weigh"
lip-rounded velar semivowel
[r] - "red"
retroflex semivowel
[l] - "lull"
lateral or liquid
Semivowels are dependent upon
speed of VT change for proper production
In the spectrograms of approximants/glides
formants are modulated
How does "I am what I am" become "I yam what I yam"?
movements are sped up and vowel becomes a glide
What is the only difference between r & l shown on spectrogram
R has an F3, L does not
What should you note on a nasal spectrogram?
vertical striations; F1 voice bar and higher formants
Why do all nasals look the same on a spectrogram?
because the nasal cavity is constant. we only hear differences because of context.
What is an affricate?
transient + noise sound sources/ stop + a fricative
How are affricates produced?
with the major VT constriction at the posterior border of the alveolar ridge
What is the longest part of an affricate?
the fricative, affricate is medium, stop is shortest
What is Voice Onset Time (VOT)?
the interval between the release of the closure and the start of vocal fold vibration for voicing
VF are closed during
voicing
VF are open during
voiceless sounds
vocal fold movement of voiced stops
closed VF vibration, occlusion release, closed vibration
Vocal fold movement of voicless unaspirated stop (s cluster)
VFs apart, occlusion release, closed VF vibration
Vocal fold movement of voiceless aspirated stop (p, t, k)
VFs apart, occlusion release, VOT then vibration
VF movement of voiced aspirated stops (Hindu, not in english)
closed VF vibration, occlusion release, VOT then vibration
There is no such thing as a stop by itself, they only exist with
the following vowel
The filter function of the VT during the noise burst of stops is solely dependent on
the volume/size of the area in FRONT of the noise source
Large volumes make ____ and smaller volumes make ___
lower frequencies, higher frequencies
Primary concentration of acoustic energy for bilabials
500-1500 Hz
Primary concentration of acoustic energy for alveolars
most prominent burst energy >4000 Hz
Primary concentration of acoustic energy for velars
1500 - 4000 Hz
What is significance of primary concentration of acoustic energy
helps with perception
How are stop consonants produced?
entirely occluding the vocal tract in various locations (place of location)
place & manner of b
voiced bilabial
place & manner of p
voiceless bilabial
place & manner of m
nasal bilabial
place & manner of d
voiced alveolar
place & manner of t
voiceless alveolar
place & manner of n
nasal alveolar
place & manner of g
voiced velar
place & manner of k
voiceless velar
place & manner of ng
nasal velar
During a stop, when the occlusion is moved to make next sound, a narrow openeing causes airflow to be turbulent and there is
a brief 'transient' noise produced
Why are stops shorter than fricatives?
articulator quickly moves away from narrow constriction to next articulatory target position when the opening width is no longer able to support turbulent air flow ("h" too big, "v" too slow), the burst ceases
How long is a stop noise burst?
20-40 msec
What is the most important factor in forming the major resonance frequency of stop bursts?
volume of VT area anterior to the place of occlusion in the VT
What can you see about resonance in the spectrogram of a fricative noise?
the resonance increases in frequency as the source of noise turbulence moves from posterior to anterior constriction (rising slope)

place of articulation - smaller volume, higher frequency of the major area of noise amplitude
The size of the volume in front of filter creates
resonance
During a fricative, constriction is
long in term of duration
When air is forced through a narrow opening, what happens?
the flow velocity increases and laminar flow becomes turbulent
What does laminar mean
the steady flow of air molecules before you get constriction
What does turbulent mean
the air molecules are tossed around as there is constriction
What is the acoustic result of turbulent molecular flow
production of noise (fricatives)
Onset of turbulence is related to the particle velocity of air flow reaching a criteria flow rate known as
Reynold's #
What is the formula for Reynold's #
Re = u h/v
The more narrow a constriction is,
the faster the velocity & the sooner the air becomes turbulent
If there is greater width (h), there is
less turbulence
How many languages are there in the world?
7-8K
What are the three sound sources in the world's languages?
voiced, noise, transient
Voicing via vocal fold vibration can co-occur with both transient and noise sound sources (T/F)
True
What are glottal vibrations
all voiced sounds
What are transients
stops, clicks, ejectives
What is noise
fricatives
How is a fricative produced?
resistance to airflow is created in vocal tract by placement of articulator near roof of mouth, air pressure drop is created across constriction. if respiratory system continues to supply air & tongue maintains position, pressure differential is maintained for relatively long time (.5 sec)
What are fricatives also known as?
Continuants
A small/narrow window has
high temporal resolution & low spectral/frequency
A large/wide window has
low temporal resolution & high spectral/frequency
What does the linear predictive coding (LPC) do?
removes periodicity of VF vibrations, only displays formant peaks/valleys
In the source-filter theory, the LPC =
the VT filter
What is the entire process for analog-to-digital conversion and digital-to-analog conversion?
original signal - anti-ahasing filter (suppression of high frequencies) - digitizing (analog to digital conversion) - processing in a computer - reconstruction (digital to analog conversion) - reconstruction filter - reconstructed signal that is heard
Nyquist frequency
the sampling rate should be at least two times the highest frequency contained in the signal
Under-sampling results in what?
aliasing; a completely different sound
How does a microphone work?
movement of disk in microphone follows air pressure, show voltage fluctuation of sound wave - convert to digital 0 & 1s
What is sampling rate?
how often a sampling should take place, higher = more accurate
The peaks of a wave are ____ ____ the low parts are ___ ___
dark formants, light formants
On a gray scale, the darker it is the
more amplitude there is
Fricatives have __ frequency
high
If you see nothing on a spectograph, it is likely a
stop
What is the X axis of a spectograph? Y axis?
time; frequency
What is sound spectrography?
an acoustic analysis that is performed using a variable band-pass filter (electronic resonator). filter is swept across the frequency scale of the input signal to indicate amount of energy present at various frequencies.
Wideband spectrograms
vertical lines; vocal tract pulses (formants); F0 (distance between harmonics) is smaller than filter bandwidth
Narrowband spectrograms
each line harmonic; F0 (distance between harmonics) is larger than filter bandwidth
The ratio of F2/F1 is a crucial cue for
vowel perception
The ratio of F2/F1 is a ___ not ___ frequency parameter
relational; absolute
Why do men have the lowest frequency?
they have the biggest vocal tracts
Peterson & Barney (1952)
first time showing energy make up of acoustics

table of averages of fundamental and formant frequencies and formant amplitudes of vowels by 76 speakers
Hillenbrand et al. 1995
same thing as Peterson & Barney, but replicated by a computer and program
What is the difference between Peterson & Barney and Hillenbrand et al?
they're pretty close, but peterson & barney were eyeballed so they aren't as reliable
What do you use Hillenbrand et al. table for?
way to know what formants should be based on size of vocal tract
How do you describe vocal tract articulatory posture?
Tongue height (high - closed-, mid, low -open)

Tongue advancement (front, back)
What is the label for tongue height?
ro
What is the label for tongue advancement?
do
Vowel height is ___ ___ to F1 frequency
inversely related
F1 of high vowels have ___ Hz
low (small ro)
F1 of low vowels have __ Hz
high (large ro)
vowel frontness is ___ related to F2 frequency
related
front vowels have a
high f2
back vowels have a
low f2
F1 is controlled by the
jaw
F2 is controlled by the
tongue (front-to-back)
F3 is controlled by the
tongue tip
As ro increases, F1 __ and F2 __
increases, decreases
As do increases, F1 __ and F2 __
decreases, increases
What are the three parameters that interact to determine formant frequencies?
do, ro, A/le
What is do
distance from glottis to highest point of tongue constriction
What is ro?
cross-sectional area between top of tongue & roof of mouth
what is a/le
lip rounding index (varies from .1 to 20 cm)
As lip rounding increases, F1 and F2 ___
decrease
What is a close analogy to the human vocal tract configuration?
double hemholtz resonator
The larger the cavity volume, the ___ the resonance
lower
The smaller the cavity volume, the __ the resonance
higher
The neck of helmhotz resonator is analogous to what?
VT lip rounding
Why does a larger area of opening port make a higher frequency?
air can rush in and out faster
Why does a larger volume create a lower frequency?
more air must move out to relieve a given pressure excess
Why does a longer neck make a lower frequency?
there is more resistance to air moving in and out
What is the formula to calculate resonances of a uniform tube?
Fn=NC/4L
Fn =
nth resonance frequency
C =
velocity of sound
L =
length of tube
N =
odd multiples ( F1: N= 1, F2: N=3,)
boundary restraints
zero pressure at open end & max pressure at closed end
What is the only vowel that can modeled with a uniform tube?
neutral vowel schwa
In a uniform tube, if the wave is in phase, it will be
resonated
What is the glottal source?
a complex 'triangular' shaped volume velocity waveform
A complex periodic waveform is very rich in
harmonic energies (frequencies)
The harmonic structure of a complex periodic wave is shaped by
the FO (rate of VF vibration) of the speaker at the time
F0 is the ___ harmonic, all the other harmonics are ___ ___ ____ of F0
1st, whole # multiples
Every shape of the VT possesses
a unique 'transfer function' that will resonate certain source harmonics & dampen other harmonic energies
The harmonics in the Vg "buzz" are the same harmonics in
the speech output signal, but their amplitudes have been altered in terms of which harmonic frequencies were resonated and which reduced
The source filter theory
source x filter = speech output

BASED ON FREQUENCY
The vocal tract has ___ transfer frequencies
multiple
During the source-filter theory, certain _______ will be formed
wavelengths/frequencies
What is a transfer function?
how input gets to output (from buzz to speech sound)
Different frequencies resonate at ___ parts of the vocal tract
different
Sound is what kind of wave?
mechanical, longitudinal, pressure
The motion of particles in sound move
parallel (and anti-parallel) to the direction of the energy transport
wavelength
the distance that a disturbance travels along the medium in one complete wave cycle
pressure wave
consists of repeating pattern of high-pressure and low-pressure regions moving through a medium
waves in water are what kind of waves?
transverse
The crest in speech is called a
compression
The trough in speech is called a
rarefaction
Resonant frequency
natural vibration rate, rate of vibration that an object vibrates with the highest amplitude
Forced vibrations induce resonance when the applied frequency ___ the inherent natural frequency of the object being forced to vibrate
matches
What is damping?
the rate at which sound goes out
You can only see damping if there is what on an axis?
TIME
Index of tuning
tells you what frequency is at 50% min/max, the range = the index
sine waves
consist of one frequency
complex waves
consist of multiple frequencies
periodic complex waves
repeats the same pattern
aperiodic complex waves
no pattern (noise/fricatives)
fundamental frequency of the speaker (f0)
the repetitive cycles of a complex periodic wave repeat at the rate of vibration of vocal folds
laryngeal burst creates
constant pattern in vowels (periodic)
every vowel has a ___ waveform, the acoustic result of a vibration
different
What does a spectrum show?
harmonic frequencies and spectrum envelope/line spectrum
Line spectrum/spectrum envelope
plots all the harmonic components & amplitude of each
On a spectrum, the formants are the
peaks
Resonance helps certain harmonics gain/lose
identification
Complex aperiodic waves can be represented by
continuous spectra
Why are harmonics not included in a continuous spectra?
way too many, energy at all frequencies
Line spectra: Glottal spectrum
spectrum of source frequencies: f0 + harmonics. no resonance.
Line spectra: Output spectrum
spectrum of harmonics of speech output waveform. has resonance! certain harmonics boosted
Fourier analysis can do what?
reduce complex waves to many simple sine waves
Repetition rate of a complex wave is determined by
the highest denominator
As period gets smaller,
pitch gets higher
Having a High Duty Cycle effects
breathy voice, weak

low amplitude of harmonics, do not extend out frequency scale
Having a Low Duty Cycle effects
broadcaster voice

greater amplitude at all lower harmonic frequencies, more high frequency harmonics,
Will changing F0 change the vowel?
No, only changing filter does. They work together, but can be independently altered.
The uniform tube is measured in
quarter wavelengths; odds
The uniform tube only applies to
the schwa
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