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Acoustics Flashcards

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1
Q

elasticity

A

Elasticity (internal stiffness) of the mass returns the mass back to its resting position (equilibrium)

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2
Q

inertia

A

Due to inertia, the mass moves beyond its rest position

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3
Q

Mass Spring Oscillator

A

The spring-mass oscillator consists of a spring (fixed at one end) that is attached to a mass which is resting on a special low-friction surface.
When not vibrating (at rest), the system is at equilibrium

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4
Q

Simple Periodic Signal

A

Always a sinusoidal waveform. Basically a pure tone. The waveform will repeat in equal periods.

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5
Q

What’s a waveform?

A

Change in some quantity over time. (Amplitude versus time)

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6
Q

What will determine the frequency of vibration?

A

the mass of the object &

the stiffness or elasticity of the object

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7
Q

Reduce Mass

A

Increases Frequency

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8
Q

Increasing Frequency

A

Reduces Mass

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9
Q

Are stiffness and frequency directly or inversely related?

A

Stiffness and Frequency have a direct relationship.

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10
Q

Are mass and frequency directly or inversely related?

A

Mass and Frequency have an inverse relationship.

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11
Q

What two properties determine the frequency of the spring-mass oscillator?

A

The spring-mass oscillator will vibrate at a frequency that is determined by its mass and stiffness

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12
Q

Period

A

the time it takes for one complete cycle of periodic vibration to occur

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13
Q

What is the x-axis of a wave form?

A

time

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14
Q

Frequency (f) and Period (T) are reciprocally related: (formula)

A

f (Hz) = 1/T (s) and T (s) = 1/f (Hz)

ex. If T = .01
1/.01 = 100 = F=100Hz

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15
Q

1000 milliseconds

A

1 second

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16
Q

50 milliseconds

A

.05 second

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17
Q

5 ms

A

.005 second

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18
Q

What determines the amplitude of vibration?

A

Magnitude of the force and degree of energy loss (damping)

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19
Q

damping

A

reduction of amplitude over time. (Energy Loss) The amplitude of vibration will gradually decrease because of energy losses in the system (friction)
For a lightly damped wave, amplitude decays slowly
For a heavily damped wave, amplitude decays rapidly

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20
Q

peak to peak amplitude

A

Distance between a waveforms peak and trough

peak to trough

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21
Q

peak amplitude

A

Distance between zero (equilibrium) and the waveform’s peak or trough

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22
Q

Propagation of a Sound Wave

A

Air particles, like the spring-mass oscillator, move in place around their rest position

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23
Q

How does a sound wave travel in air?

A

When air particles are disturbed, they behave like small masses connected to one another by springs. (Air, an elastic medium)

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24
Q

Simple sound waves in air

A

When a tuning fork is struck, air particles will move in place about their theoretical rest positions

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25
Q

Which is shorter in wavelength? Men or Women’s speech?

A

Typically women’s.

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26
Q

Which is lower in frequency? Men or Women’s speech?

A

Typically men’s.

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27
Q

Describe the relation of wavelength and frequency.

A

Wavelength and frequency are inversely related. Higher frequency sounds correspond to shorter wavelengths, and lower frequency sounds correspond to longer wavelengths.

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28
Q

wavelength equation using words

A

wavelength = velocity (of sound) X frequency.

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29
Q

How is frequency measured?

A

Hz

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30
Q

What answers the question “How Often”?

A

frequency

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31
Q

What answers the question “How fast”?

A

speed

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32
Q

Which material generally has the strongest bond between molecules? (solid, liquid, or gas?)

A

solids

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33
Q

Why does sound travel faster through solids?

A

strong bonds in solid materials allows particles to interact with each other more easily than weaker bonds.

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34
Q

How does air pressure influence the speed of sound?

A

Air pressure influences the density of the air. Greater pressure = increased density of particles.

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35
Q

How does temperature influence the speed of sound?

A

Temperature influences the strength og the interaction between particles. Higher temperature causes interaction between particles to become more elastic (they are more easily separated)

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36
Q

True or false: the speed of a sound wave is dependent upon its frequency or wavelength?

A

false: The speed of a sound wave can be altered only by the properties of the medium which it travels (density, temperature, etc.)

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37
Q

Why do sounds travel farther at night?

A

This effect is due to temperature and refraction. In the day air is warmer toward the ground than the higher air above. This causes refraction- A difference in velocity causes the sound to bend upward to the cooler air. At night, air is cooler toward the ground and the sound waves bend downward. As a result, the sound waves appear to be traveling farther, as they stay closer to the ground across a greater distance.

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38
Q

What is our perception of pitch based on?

A

It is strongly based on the frequency of the sound wave, but it is also influenced by the intensity of the sound.

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39
Q

What is our perception of loudness based on?

A

Our perception of loudness is primarily based on intensity, but is also strongly influenced by frequency.

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40
Q

What is the JND (just noticeable difference) between two sounds that can be measured?

A

about 1 decibel (but if very loud can drop to half a decibel)

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41
Q

If two sounds are equally “loud” (60 dB SPL) but at different frequencies, will they be perceived as equally loud?

A

No, the sensitivity of the ear is frequency dependent.

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42
Q

spectrum

A

amplitude (y axis) versus frequency (x axis)

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43
Q

What kind of sounds will have line spectra?

A

periodic

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44
Q

JB Fourier

A

Showed mathematically that all complex periodic sounds are made up of or can be broken down into a set of sine waves of different frequency, amplitude, and phase.

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45
Q

How does sound wave travel in air?

A

When a tuning fork is struck, air particles will move in place about their theoretical rest positions
As the disturbance moves away from the source, air particles will alternately become more densely packed (compression areas) and more widely dispersed (areas of rarefaction)

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46
Q

When air particles are disturbed, what do they behave like?

A

When air particles are disturbed, they behave like small masses connected to one another by springs. (Air, an elastic medium)

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47
Q

Sound wave in air is an example of a ….

A

Longitudinal wave

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48
Q

The particles of the medium move in _______________ as the wave.

A

The particles of the medium move in the same direction as the wave.

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49
Q

A ripple in water is an example of a ______ wave

A

A transverse wave

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50
Q

Sound in air is an example of a ________ wave.

A

A longitudinal wave

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51
Q

Propagation Velocity (C):

A

The speed of sound in air

Under normal atmospheric conditions (18o C), a sound wave will travel approximately 343 m/s

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52
Q

What is the speed of sound in air in normal atmospheric conditions (18o C)?

A

343 m/s

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53
Q

Wavelength

A

The distance in space spanned by one cycle of periodic wave motion; measured usually in meters

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54
Q

What’s the difference between period and wavelenth?

A

period is time; wavelength is distance

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55
Q

Symbol for wavelength

A

lambda λ

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56
Q

λ =

A

λ = CT (C=propagation velocity), Period = T

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57
Q

T=

A

1/F (period)

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58
Q

If a male has a 100Hz frequency what is the size of the wavelength?

A

(You need to know that speed of sound is always 343 m/s

use formula wavelength = C*T. Divide the 343 by the frequency (100) = 3.43 m

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59
Q

How do sounds cancel each other out?

A

When you have two sine waves with identical frequency that are 180 degrees out of phase toward each other, they will cancel each other out ( destructive interference)

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60
Q

What’s the minimum amount you have to shift a sine wave over another to quantify phase relationship

A

90 degrees; nothing can be greater than 180

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61
Q

Complex signals consist of

A

Complex signals consist of more than one frequency

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62
Q

What might you say to describe complex aperiodic sounds?

A

noise

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63
Q

Who discovered that any complex waveform can be broken down into a set of sine waves of different frequency, amplitude, and phase

A

J.B. Fourier

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64
Q

How are sine waves that make up complex periodic signal’s related?

A

harmonically related (occurring in different whole number intervals)

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65
Q

What’s a harmonic?

A

Whole number multiples of the fundamental

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66
Q

Each sine wave that makes up a complex periodic wave is an

A

harmonic

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67
Q

Describe the harmonic structure of the following complex periodic signals:
fo = 100 Hz fo = 250 Hz

A

The 100Hz will have the first harmonic (the most evergy) at 100 Hz, There will be another at 200, 300, and 400 (the spacing will be equal to the fundamental frequency)

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68
Q

How much of the glottal amplitude signal drops off

A

Generally it is 6-12 dB an octave below below 1000 Hz

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69
Q

What’s an octave?

A

a doubling of a frequency

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70
Q

What does a spectrum display?

A

A spectrum is an amplitude vs frequency display

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71
Q

What do the lines in a spectrum represent?

A

the harmonic

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72
Q

periodic waveforms have a

A

line spectra

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73
Q

Complex Aperiodic signals consist of

A

Complex Aperiodic signals consist of multiple frequencies, but the pattern of vibration does not repeat itself (random noise)

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74
Q

Are frequencies harmonically related?

A

Frequencies are not harmonically related

Rather, energy is distributed over a range of frequencies

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75
Q

transient complex

A

dissapears

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76
Q

continuous complex periodic sounds

A

continues

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77
Q

complex aperiodic sounds have what kind of spectrum?

A

continuous line spectrum

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78
Q

duration of noise can be described as

A

transient or continuous; this is only for complex aperiodic sounds

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79
Q

What can’t /m/ be described as continuous?

A

It is not noise, because it is quasi-periodic complex

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80
Q

Aperiodic sounds (noise) can be

A

transient or continuous

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81
Q

describe /s/

A

continuous aperiodic sound

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82
Q

Describe /g/

A

continuous aperiodic sound

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83
Q

continuous specta

A

consists of energy over a wide range of frequencies, with the max frequency concentrated (usually somewhere in the middle)

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84
Q

How are periodic sounds different from aperiodic sounds?

A

Unlike periodic sounds that have energy present at discrete frequencies (harmonics), aperiodic sounds have a band of energy distributed over a wide range of frequencies.

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85
Q

describe /m/

A

complex quasi periodic

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86
Q

describe /ae/

A

complex quasi periodic

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87
Q

describe /l/

A

complex quasi periodic

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88
Q

describe /k/

A

transient complex aperiodic

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89
Q

describe /f/

A

continuous complex aperiodic

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90
Q

describe /v/

A

complex quasi periodic and continuous complex aperiodic (because from two sources)

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91
Q

describe /dʒ/

A

complex quasi periodic and transient complex aperiodic (because from two sources)

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92
Q

describe /b/ /d/ or /g/ initially

A

transient complex aperiodic sounds

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93
Q

describe /b/ /d/ or /g/ in a medial position

A

complex quasi periodic and transient complex aperiodic

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94
Q

Voice Onset Time (VOT)

A

the time it takes from the release of a stop to the vibration for the following sound

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95
Q

Voice Onset Time (VOT) for initial b

A

10-15 ms

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96
Q

What would have a VOT of 0

A

voiced sounds (truly voiced sounds), when the voicing happens the same time as the stop.

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97
Q

How are most consonants produced?

A 
Most consonants are produced as a result of either vocal fold vibration (a complex quasi-periodic sound source) or noise created in the vocal tract/oral cavity (complex aperiodic sound source).
One class of consonant sounds is produced by both sound sources simultaneously
98
Q

Transient Complex Aperiodic

A

Voiceless Stops and Affricate /p, t, k, tš/ and the “voiced” Stops /b, d, g/ (in syllable releasing position: CV)

99
Q

Aperiodic and Quasi-Periodic

A

Voiced Fricatives and Affricate

100
Q

Which class of consonant sounds is produced by both sound sources simultaneously?

A

Aperiodic and Quasi-Periodic : Voiced Fricatives and Affricate

101
Q

What is always the Y axis for a spectrogram?

A

Frequency

102
Q

How to describe an acoustic spectra of a sound.

A

describe the range of energy, and where the maximum energy is.

103
Q

What is the energy of vowels?

A

harmonics

104
Q

How high do most vowels go?

A

3k Hz

105
Q

Range for spectrograms for speech analysis should be what?

A

0 HZ- 8000 Hz

106
Q

What kind of sounds have line spectra?

A

complex periodic sounds- transient and continuous

107
Q

Everyday example of a mechanical filter?

A

A Brita, a coffee filter, Sorts things out by particle size and diameter.

108
Q

Resonance Frequency (source-filter)

A

Has to do with the cavities of the super laryngeal vocal tract

109
Q

what are the two ends of the vocal tract?

A

the larynx, the lips

110
Q

What does changing the cross sectional area of the vocal tract do?

A

the resonance frequency

111
Q

cross-sectional area (of the vocal tract)

A

Think of vowel quadrilateral,

112
Q

How do you change the cross sectional area of the vocal tract?

A

Place of constriction, degree of constriction, and vocal tract length (rounding)

113
Q

What is on the x axis of a vowel quadrilateral?

A

degree of tongue advancement

114
Q

What is on the y-axis of a vowel quadrilateral?

A

tongue height

115
Q

contrast /i/ and /u/ and cross sectional area.

A

Both high vowels, the place of constriction is moving from the pharynx to the oral cavity. The relative size of the cavity is shorted. The pharyngeal cavity becomes larger. I has retracted lips and u is rounded, U then has a longer vocal tract length.

116
Q

What happens when you change the cross sectional area of a vowel?

A

the quality of the vowel changes

117
Q

What is the simplest acoustic filter?

A

The Helmholtz filter (has one resonance frequency) Like a beer bottle

118
Q

The Helmholtz filter

A

An enclosed body of air with a neck ( like a beer bottle) Frequency is determined by air volume.

119
Q

How can you lengthen your vocal tract?

A

lip protrusion and lowering the larnyx

120
Q

The Helmholtz filter

A

An enclosed body of air with a neck ( like a beer bottle) Frequency is determined by air volume. The air is acting like the spring component.

121
Q

How can you lengthen your vocal tract?

A

lip protrusion and lowering the larynx

122
Q

What is the double Helmholtz Resonator

A

In this model, oral and pharyngeal cavities are represented by separate volumes (2 coupled Helmholtz Resonators)

123
Q

How many frequencies do you need to differentiate vowels?

A

Only 2

124
Q

How does the double Helmholtz resonator work?

A

V1 (back cavity) and V2 (oral cavity) are connected by the neck cavity (tonue-palate) and V2 has a neck that represents the lips.

125
Q

R1 (resonance 1)

A

The pharyngeal cavity

126
Q

R2 (Resonance 2)

A

The oral cavity

127
Q

As the place of constriction moves forward what happens to frequency?

A

F1 goes down and F2 goes up

128
Q

When you round lips what happens to R1 and R2?

A

They lower

129
Q

Anytime you change the cross sectional area of the vocal tract what happens to resonance?

A

Resonance frequencies change (formant structure and quality of what you hear)

130
Q

What is the most constricted vowel we have?

A

/i/ (it’s also has the furthest separated f1 and f2)

131
Q

What affect does going from rounded lips to spread lips have?

A

The vocal tract shortens, increasing the resonance of R1 and R2

132
Q

Acoustic Transmission Line Model

A

Only valid for one vowel (the neutral vowel /ʌ?
We can model the vowel tract as a uniform tube that is open at one end. The glottal end is considered closed because the vocal folds are rapidly vibrating, whereas the mouth is open.

133
Q

Two characteristics of the Acoustic Transmission Line Model

A

the wavelength of R1 will be 4 times the length of the tube. Sometimes this is called a quarter length resonator.. Because at R1 only a quarter of the wavelength fits in the tube.
The other characteristic of quarter length resonators is that they resonate only at odd multiples. Meaning is the lowest resonance is 650 Hz, R2 3XR1, R3 5XR1

134
Q

What do acoustic filters sort sounds by?

A

according to wavelength frequency

135
Q

R1=

A

c/wavelength

136
Q

Low pass filter

A

Only low frequencies pass, anything higher drops off

137
Q

high pass filter

A

blocks low frequencies, anything higher is allowed to pass

138
Q

a bandpass filter

A

two cut of frequencies (a high and low), alowing a band of frequencies in between to pass

139
Q

describe the vocal tract as a filter

A

a multiple band pass filter

140
Q

What makes up formant bands on a wide band spectrogram?

A

High energy harmonics; those that are closest to the natural resonate frequency

141
Q

What makes up the formant bands on a narrow band spectrogram?

A

the harmonics

142
Q

What’s the band width for a narrow band spectrogram?

A

45-50 Hz wide

143
Q

What’s the band width for a wide band spectrogram?

A

about 300 Hz wide

144
Q

Narrow Band Spectrogram advantage

A

Spectrogram is Frequency vs. time vs amplitude; Going to get improved y axis (frequency) resolution but will lose resolution of the time axis

145
Q

Wide Band Spectrogram Advantage

A

Spectrogram is Frequency vs. time vs amplitude; Going to get improved x axis (time) resolution but will lose resolution of the frequency axis

146
Q

What are the vertical bands (striations) on a spectrogram?

A

Vocal fold vibrations, The line is the opening (the puff of air) (source)

147
Q

What do the dark bands (F1) (F2) represent?

A

locations of the resonant frequencies of the vocal tract

148
Q

If you want to see clear harmonics, which spectrogram would you use (wide or narrow)?

A

Narrow= Because you can’t see any harmonics in a wide band.

149
Q

What is shown on a spectrogram? (plotted on each axis)

A

x= frequency y=time

150
Q

z axis of a spectrogram

A

amplitude (darkness// areas of grey on a paper)

151
Q

How much time is needed for a spectrogram? (with 8K Hz)

A

2.2-2.5s

152
Q

Why do we see formants (bands) on a wide band spectrogram?

A

poor frequency resolution- you can’t see individual harmonics

153
Q

If you want to look at harmonic structure (hoarseness or roughness) - inter harmonic energy

A

narrowband

154
Q

2 acoustic features that coorrelate very highly with vocal roughness/hoarseness

A

horse vowels have a lot of high frequency energy (noise) indicated by energy above 3000 hz (a good quality vowel would be white above 3000 hz), and interharmonic energy (the noise between harmonics)

155
Q

What causes inter-harmonic energy?

A

nodules and other lesions in the larynx ? Causes turbulence in the air flow.

156
Q

If the F0 doesn’t change for a vowel, what would the striations look like on a spectrogram?

A

striations are equally spaced

157
Q

When frequency goes up, how do the striations of a spectrogram change? (like the end of a sentence in a question)

A

striations will compress and come closer together.

158
Q

When frequency goes up, how do the striations of a spectrogram change?

A

striations will move closer together

159
Q

A power spectrum

A

A graph of frequency and amplitude spectrum at an instant in time; like a snapshot of a part of a word.

160
Q

What power spectrums would you see in the word “she” ?

A

sh= continuous /i/= line

161
Q

What do the formant frequencies represent?

A

resonant frequencies (determined by the cross sectional area)

162
Q

Loudness vs. intensity

A

Loudness is a psychological sensation of perceived intensity. The human ear perceives loudness differently depending on a sound’s frequency (and spectral characteristics)
That is, the ear is a more efficient transducer at certain frequencies and less efficient at others

163
Q

What is a graph that illustrates an interesting phenomenon of human hearing where the actual loudness changes but the perceived loudness our brains hear will change at a different rate, depending on the frequency.

A

Fletcher Munson Curve

164
Q

measure for amplitude on dB scale

A

dBSPL

165
Q

measure for Intensity on dB scale

A

dBIL

166
Q

How does the Fletcher-Munson curve work?

A

The Fletcher-Munson curves show us that sounds at the extreme frequencies must be of greater IL to be heard “as loud” as sounds in the middle frequencies (2-4 kHz) it shows that Because the ear perceives loudness differently depending on the sound’s frequency, not all equally intense sounds are perceived as equally loud.

167
Q

the unit for loudness

A

phon

168
Q

definition of loudness

A

Loudness, the psychological correlate of intensity, is scaled differently.

169
Q

What is the phon scale?

A

The phon scale was arbitrarily created. A 10 dB IL sound presented at 1000 Hz has a loudness of 10 phons; a 20 dBIL sound at 1000 Hz is 20 phons, etc.

170
Q

At what frequency is the ear more sensitive to hearing the difference in frequency?

A

The ear is more sensitive to frequency differences below 1000 Hz, than it is to frequency differences above 1000 Hz.

Consequently, 2 tones separated by the same frequency difference (100 Hz, e.g.), will be perceived as having a greater difference in pitch below 1000 Hz.
For Example, which pair of tones would the listener judge to have a greater difference in pitch?
1000 Hz - 1100 Hz (f = 100 Hz)
100 Hz - 200 Hz (f = 100 Hz)

171
Q

What is pitch?

A

Pitch is a perceptual attribute of frequency

172
Q

Relationship between frequency and pitch

A

Pitch is a perceptual attribute of frequency

173
Q

Are pitch and frequency the same?

A

NOOO- and not a linear relationship about 1000 Hz

174
Q

What diagram reveals the relationship between pitch and frequency?

A

The Stevens-Volkmann curve reveals the relationship between pitch and frequency
The relationship is linear below 1000 Hz, becoming nonlinear above 1k Hz
- (line starts with equal relationship then drops off)

175
Q

semitone scale

A

devised to account for the nonlinear growth of pitch and frequency.

176
Q

100-200 Hz and 1000-2000 Hz on a semitone scale

A

both are 12 ST

177
Q

intensity

A

the power of a sound or power/area

178
Q

amplitude

A

the pressure of a sound

179
Q

A common unit of power

A

Watts

180
Q

A common unit of area

A

cm 2 (squared)

181
Q

How is Intensity usually measure (although inconveniently)?

A

watts per square centimeter

182
Q

Why is it hard to describe intensity? (watts per cm 2)

A

the human auditory mechanism is sensitive to a wide range of powers, from the just detectable 10 to the minus 16 watts per centimeter (o dB) to a painfully loud 10 to the minus 2 watts per centimeter squared- represents a range of about 100 tillion to one) (you need smaller numbers, it’s inconvienent. 2) 3) our own interest in relative intensity

183
Q

Why is it hard to describe intensity? (watts per cm 2)

A

1) the human auditory mechanism is sensitive to a wide range of powers, from the just detectable 10 to the minus 16 watts per centimeter (o dB) to a painfully loud 10 to the minus 2 watts per centimeter squared- represents a range of about 100 trillion to one) (you need smaller numbers, it’s inconvenient. 2) Relationship between intensity & loudness is not linear
3) our own interest in relative intensity

184
Q

How is relative intensity quantified?

A

quantified as the logarithm of the ratio of an observed sound power/pressure to a standard reference power/pressure

185
Q

What is a unit of relative intensity?

A

dB

186
Q

dbIL

A

a ratio of two acoustic powers expressed on a log scale; the numerator is the observed power; it’s a unit of relative intensity and the standard reference will always be 10 -16 power

187
Q

What is a synonym for logarithm?

A

exponent (a convenient mathematical shorthand)

188
Q

What is the logarithm of 100?

A

2

189
Q

What is the logarithm of 1000?

A

3

190
Q

What is a power ratio?

A

Intensity Level

191
Q

What is a power ratio?

A

Intensity Level (dBIL)

192
Q

What is a pressure ratio?

A

Sound Pressure Level (dBSPL)

193
Q

symbol for power

A

W

194
Q

symbol for pressure

A

P

195
Q

When would you use dBIL (intensity) in a logarithm?

A

When IL = 10 log (Wo/ Wr); where the standard reference power (Wr) is 10-16 W/cm2

196
Q

If power is doubled in dBIL, how much will IL increase?

A

If power is doubled, IL will increase by 3 dB; a tenfold increase in power will result in a 10 dB IL increase

197
Q

dBSPL (amplitude)

A

SPL = 20 log (Po/Pr); where the standard reference pressure (Pr) is 0.0002 dynes/cm2

198
Q

If power is doubled in dB SPL, how much will SPL increase?

A

If pressure is doubled, SPL will increase by 6 dB; a tenfold increase in pressure will result in a 20 dB SPL increase

199
Q

If two babies are crying at equally loud 80 dBIL, what will be the net dbIl?

A

83 dBIL because again If power is doubled, IL will increase by 3 dB;

200
Q

dBGain

A

Gain expressed in decibels for voltage and pressure.

201
Q

What is gain?

A

describes the properties of an amplifier; Gain is a ratio of an amplifiers output to the input.

202
Q

What’s the log of 10?

A

1

203
Q

How do we form s?

A

forming a major constriction near the alveolar ridge, but the constriction can happen in different ways.

204
Q

What is a 2-2 model for the s sound?

A

an s constriction represented by a uniform tube open at both ends including a quarter length wave resonator and a halfway resonator.

205
Q

Quarter wave resonators (open at one end) wavelength

A

the wavelength of the R1 is four times the length of the tube

206
Q

Halfway resonator (open at both ends) wavelength

A

the wavelength of R1 is two times the length of the tube

207
Q

For a half wave resonator what is resonance frequency for R2, R3, and R4 in relation to R1?

A

For a the second resonance frequency is 2R1,
For a third resonance frequency is 3R1,
For a 4th resonance frequency is 4* R1

208
Q

For a quarter wave resonator, what is resonance frequency for R2, R3, and R4 in relation to R1?

A

For a the second resonance frequency is 3R1,
For a third resonance frequency is 5R1,
For a 4th resonance frequency is 7*R1

209
Q

If the length of the tube in a half way resonator is 2.5 cm? How can you calculate the maximum energy of an s sound?

A

λ = CT (C=propagation velocity; always 343 m/s), Period = T;

210
Q

Spectrogram benefits

A

It’s an acoustic signal (non invasive- just talking into a microphone). Tells us what is going on at the physiological level of the vocal tract. Tell us valuable information about what’s going on with the sound source and the vocal tract filter.

211
Q

What is a spectrogram?

A

a hard copy of from spectrography; a 3d visual representation of sound; y axis is frequency, x axis is time, z-axis is intensity/amplitude (in grey or black)

212
Q

When should formants not be changing in a spectrogrom?

A

a sustained vowel?

213
Q

What kind of spectrogram shows formants?

A

Narrow band

214
Q

Formats are indicative of source or filter in a spectrogram?

A

filter

215
Q

Vertical bands (striations) are indicative of source or filter on a spectrogram?

A

source

216
Q

If vertical striations are moving farther apart or closer together on a spectrogram for a sustained vowel, where in the vocal tract does the instability lie?

A

source

217
Q

Change in formants means what?

A

change in filter (cross sectional area)

218
Q

In a wideband spectrogram if vertical striations are more closely spaced it means that there is a _______FO in comparison to another sound.

A

a higher FO

219
Q

When is the end of VOT?

A

When voicing begins; on a spectrogram at the first vertical striations that passes through f1 and f2; it is relatively short for “voiced” stops and it is longer for “voiceless” stops. A simple temporal measure used for stops.

220
Q

VOT is a good measure of a speakers ability to coordinate __________
____ ______________
__________________events.

A

VOT is a good measure of a speakers ability to coordinate laryngeal and superlaryngeal articulatory events.

221
Q

laryngeal event in VOT

A

vocal fold vibration

222
Q

superlaryngeal in VOT

A

release of a stop

223
Q

If the vertical striations in a side band spectrogram move further apart, what does this mean about F0 and most likely why?

A

F0 is dropping (lowering)- for a declarative sentece

224
Q

Hallmarks of /m/,/n/ and /ng/ on a wideband spectrogram?

A

vertical striations and structure will be very light compared to a vowel because of damping and energy loss when they pass through the nasal cavity.

225
Q

How to (manually) find F0 on a wideband?

A

Count the verticle striations but you need to know the time interval (difficult)

226
Q

How to (manually) find F0 on a narrowband?

A

You need to know the frequencies (on the y-axis); find a convenient harmonic, high on the page that you can count up to reliably. Find which harmonic it is (for ex. 20th harmonic at 3500 Hz) (3500/20= 175 Hz)

227
Q

Harmonics are wider or closer spaced for higher f0s

A

Wider

228
Q

Verticle Striations in a wide bad

A

those in the glottal source that fell closest in frequency to the resonant frequencies in the vocal tract

229
Q

What spectrogram would you need to see interharmonic energy?

A

Spectrogram - the only one you will see harmonincs?

230
Q

sound source for /a/

A

vocal fold vibration

231
Q

Narrow band higher FO then harmonics are ……

A

higher f0 harmonics are more widely spaced

232
Q

wide band, higher FO the verticle striations are…

A

verticle striations are closer together

233
Q

If a first harmonic is 4 HZ, What is the 20th harmonic?

A

4 times 20 = 80 Hz

Harmonics are multiples of the first harmoinic.

234
Q

sound sources for /dg/

A

vocal fold vibrations and noise in the oral cavity

235
Q

/dg/

A

transient complex aperiodic, and complex quasi periodic

236
Q

What spectrum would voiced /th/ have?

A

combined spectrum

237
Q

What spectrum would /f/ have?

A

continuous

238
Q

vocal fold vibration spectrum

A

line spectrum

239
Q

noise in the oral cavity specturm

A

continuous spectrum

240
Q

/h/ sound source

A

glottis (vocal folds) but not vibration

241
Q

sound spectrum for /h/

A

continuous spectrum (it’s noise)

242
Q

How long is VOT for voiceless stops?

A

anything over 20 milliseconds

Speech Science (3 decks)

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