Exam 2

Question 1

what is a sound?

Answer 1

small and rapid variations in pressure in a fluid medium (air or water)

Question 2

what is a sound wave?

Answer 2

the variation in pressure over time

Question 3

what is waveform or an oscillogram?

Answer 3

plots the pressure of a sound wave at a given location at each instant of time

Question 4

what is a periodic wave?

Answer 4

a wave with the same pattern of air pressure variation repeated exactly over and over

Question 5

how are frequency and amplitude percieved?

Answer 5

frequency as pitch and amplitude as loudness

Question 6

in a periodic wave each repetition is called a what?

Answer 6

cycle

Question 7

what’s a wave that isn’t periodic?

Answer 7

aperiodic

Question 8

what is a sine wave?

Answer 8

periodic wave that has a smooth and symmetrical curve connecting the points of maximum and minimum pressure

Question 9

a sine wave can be defined by what parameters? why?

Answer 9

frequency and amplitude - because it’s a simple wave

Question 10

a sine wave is what type of sound?

Answer 10

pure tone

Question 11

what is frequency?

Answer 11

the number of times a wave repeats itself during a unit of time

Question 12

what is the unit of frequency?

Answer 12

Hertz or cps (cycles per second)

Question 13

if a tuning fork repeats once every .01 seconds - how many hertz is it?

Answer 13

100 Hz, repeats 100 times per second

Question 14

___ frequency –> ___ pitch

Answer 14

higher, higher

Question 15

pitch is what?

Answer 15

psychological

Question 16

what is amplitude?

Answer 16

the magnitude of the pressure variation in the wave - the difference between the peak pressure and average atmospheric pressure

Question 17

loudness is what?

Answer 17

psychological

Question 18

any wave that is NOT a sine wave is what?

Answer 18

a complex wave

Question 19

all sound waves in the real world are what type of waves?

Answer 19

complex wave

Question 20

what is Fourier’s Theorem?

Answer 20

any complex wave can be analyzed as a combination of superimposed sine waves

Question 21

how are two waves superimposed?

Answer 21

their pressures at a particular point in time are added together

Question 22

what’s a frequency spectrum?

Answer 22

the distribution of energy over frequencies, it shows the amplitude of each component sine wave in the complex wave

Question 23

what is a wave that is almost periodic?

Answer 23

quasiperiodic

Question 24

why can’t any sound be truly periodic?

Answer 24

because it’s required to go on forever

Question 25

what components make up the pitch of complex sounds?

Answer 25

fundamental frequency and harmonic spacing

Question 26

what is the fundamental frequency of a complex sound?

Answer 26

the lowest frequency in the frequency spectrum

Question 27

what are harmonics?

Answer 27

while number multiples of the fundamental frequency

Question 28

the strongest peaks of a frequency spectrum are called what?

Answer 28

formants

Question 29

what is fundamental frequency?

Answer 29

the frequency at which the whole wave repeats

Question 30

in speech, fundamental frequency is determined by what?

Answer 30

the frequency of vocal fold vibrated

Question 31

the space between successive harmonics is equal to what?

Answer 31

the fundamental frequency

Question 32

what changes in speech sounds between sounds like [i] and [u]?

Answer 32

changes in formants

Question 33

what is quality?

Answer 33

all the perceived properties of a sound aside from its overall loudness, pitch and duration

Question 34

when two different instruments play the same note at the same loudness they sound different - why?

Answer 34

they differ in quality

Question 35

what is a source?

Answer 35

what got the sound pressure fluctuating in an audible way

Question 36

what is a filter?

Answer 36

a sound-making device sound passes through that strengthens some frequency components and weakening others

Question 37

what is resonant frequency?

Answer 37

the frequency at which it will vibrate with the minimal input of energy

Question 38

what is the general rule of resonant frequencies?

Answer 38

the LARGER the object is, the LOWER the resonant frequency (longer has lower)

Question 39

pianos have multiple resonant frequencies - why?

Answer 39

there are multiple vibrating parts and chambers of air inside the complex object

Question 40

what is a spectrogram?

Answer 40

a display of how the frequency spectrum changes over time - vertical axis: frequency, horizontal axis: time, degree of darkness: amplitude at a given frequency and time

Question 41

why was the spectrogram invented?

Answer 41

AT&T made it for deaf people to use the phone by reading the spectrogram but it didn't work it was too hard to read

Question 42

vowels are sonorants meaning what?

Answer 42

they are produced without turbulent airflow

Question 43

a sound wave for a sonorant is what?

Answer 43

quasiperiodic

Question 44

vowels are distinguished from sonorant consonants by being what?

Answer 44

longer and more intense

Question 45

what are the small lines on a spectrogram?

Answer 45

voicing pulses

Question 46

F1 represents what?

Answer 46

formant 1- the vowel height - the lower the vowel, the higher the F1

Question 47

in low vowels, what does F1 look like?

Answer 47

F1 is widely separated from the baseline

Question 48

in high vowels, what does F1 look like?

Answer 48

F1 is right on the baseline

Question 49

F2 represents what?

Answer 49

formant 2 - vowel backness - the more front a vowel, the higher the F2 frequency

Question 50

in front vowels, what's the relationship between F1 and F2?

Answer 50

F1 and F2 are widely separated

Question 51

in back vowels, what is the relationship between F1 and F2?

Answer 51

F2 is right on top of F1

Question 52

what does the source determine in a sound?

Answer 52

the fundamental frequency and the harmonics

Question 53

what does the filter determine in a sound?

Answer 53

the formants

Question 54

vowels are differentiated by what in a spectrogram?

Answer 54

the formants

Question 55

when the lips are rounded what happens to the vocal tract?

Answer 55

lengthens the vocal tract therefore lowering the resonant frequency

Question 56

in terms of tongue constriction, how is the resonant frequency effected?

Answer 56

the further back the tongue constriction, the lower the resonant frequency - because bigger things (mouth cavity) have a lower resonant frequency

Question 57

what is the average length of the adult vocal tract?

Answer 57

males: 16.9 cm. long females: 14.1 cm long

Question 58

women's vocal tracts are generally shorter than men's, how does this effect their speech sounds?

Answer 58

higher formants, higher resonant frequency

Question 59

what is a wide-band spectrogram?

Answer 59

makes the formants more visible but blurs the harmonics together

Question 60

what is a narrow-band spectrogram?

Answer 60

harmonics are clearly visible

Question 61

when pulses are falling on a spectrogram, what does that mean?

Answer 61

the pitch is falling

Question 62

what is speech synthesis?

Answer 62

the production of speech by a machine