Exam 2 Flashcards
what is a sound?
small and rapid variations in pressure in a fluid medium (air or water)
what is a sound wave?
the variation in pressure over time
what is waveform or an oscillogram?
plots the pressure of a sound wave at a given location at each instant of time
what is a periodic wave?
a wave with the same pattern of air pressure variation repeated exactly over and over
how are frequency and amplitude percieved?
frequency as pitch and amplitude as loudness
in a periodic wave each repetition is called a what?
cycle
what’s a wave that isn’t periodic?
aperiodic
what is a sine wave?
periodic wave that has a smooth and symmetrical curve connecting the points of maximum and minimum pressure
a sine wave can be defined by what parameters? why?
frequency and amplitude - because it’s a simple wave
a sine wave is what type of sound?
pure tone
what is frequency?
the number of times a wave repeats itself during a unit of time
what is the unit of frequency?
Hertz or cps (cycles per second)
if a tuning fork repeats once every .01 seconds - how many hertz is it?
100 Hz, repeats 100 times per second
___ frequency –> ___ pitch
higher, higher
pitch is what?
psychological
what is amplitude?
the magnitude of the pressure variation in the wave - the difference between the peak pressure and average atmospheric pressure
loudness is what?
psychological
any wave that is NOT a sine wave is what?
a complex wave
all sound waves in the real world are what type of waves?
complex wave
what is Fourier’s Theorem?
any complex wave can be analyzed as a combination of superimposed sine waves
how are two waves superimposed?
their pressures at a particular point in time are added together
what’s a frequency spectrum?
the distribution of energy over frequencies, it shows the amplitude of each component sine wave in the complex wave
what is a wave that is almost periodic?
quasiperiodic
why can’t any sound be truly periodic?
because it’s required to go on forever
what components make up the pitch of complex sounds?
fundamental frequency and harmonic spacing
what is the fundamental frequency of a complex sound?
the lowest frequency in the frequency spectrum
what are harmonics?
while number multiples of the fundamental frequency
the strongest peaks of a frequency spectrum are called what?
formants
what is fundamental frequency?
the frequency at which the whole wave repeats
in speech, fundamental frequency is determined by what?
the frequency of vocal fold vibrated
the space between successive harmonics is equal to what?
the fundamental frequency
what changes in speech sounds between sounds like [i] and [u]?
changes in formants
what is quality?
all the perceived properties of a sound aside from its overall loudness, pitch and duration
when two different instruments play the same note at the same loudness they sound different - why?
they differ in quality
what is a source?
what got the sound pressure fluctuating in an audible way
what is a filter?
a sound-making device sound passes through that strengthens some frequency components and weakening others
what is resonant frequency?
the frequency at which it will vibrate with the minimal input of energy
what is the general rule of resonant frequencies?
the LARGER the object is, the LOWER the resonant frequency (longer has lower)
pianos have multiple resonant frequencies - why?
there are multiple vibrating parts and chambers of air inside the complex object
what is a spectrogram?
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
why was the spectrogram invented?
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
vowels are sonorants meaning what?
they are produced without turbulent airflow
a sound wave for a sonorant is what?
quasiperiodic
vowels are distinguished from sonorant consonants by being what?
longer and more intense
what are the small lines on a spectrogram?
voicing pulses
F1 represents what?
formant 1- the vowel height - the lower the vowel, the higher the F1
in low vowels, what does F1 look like?
F1 is widely separated from the baseline
in high vowels, what does F1 look like?
F1 is right on the baseline
F2 represents what?
formant 2 - vowel backness - the more front a vowel, the higher the F2 frequency
in front vowels, what’s the relationship between F1 and F2?
F1 and F2 are widely separated
in back vowels, what is the relationship between F1 and F2?
F2 is right on top of F1
what does the source determine in a sound?
the fundamental frequency and the harmonics
what does the filter determine in a sound?
the formants
vowels are differentiated by what in a spectrogram?
the formants
when the lips are rounded what happens to the vocal tract?
lengthens the vocal tract therefore lowering the resonant frequency
in terms of tongue constriction, how is the resonant frequency effected?
the further back the tongue constriction, the lower the resonant frequency - because bigger things (mouth cavity) have a lower resonant frequency
what is the average length of the adult vocal tract?
males: 16.9 cm. long
females: 14.1 cm long
women’s vocal tracts are generally shorter than men’s, how does this effect their speech sounds?
higher formants, higher resonant frequency
what is a wide-band spectrogram?
makes the formants more visible but blurs the harmonics together
what is a narrow-band spectrogram?
harmonics are clearly visible
when pulses are falling on a spectrogram, what does that mean?
the pitch is falling
what is speech synthesis?
the production of speech by a machine
