sound production Flashcards
what is a monopole
where a sac inflates and contracts
what is a dipole
something moves back and forth along an axis
what happens if the sound source is small relative to the wavelength
the sound produced is easily short-circuited (the waves will propagate from one side of the moving surface to the opposite side and thus not radiate any sound outwards)
if animal size is less than or equal to the wavelength what happens
short circuiting becomes a problem, sound will go backward and not forward
if wavelength is < cricket length then
sound will propagate forward
how do tree crickets overcome short circuiting
cut hole in leaf and put wings through to vibrate wings
there is amplitude modification
what is another solution to short circuiting
limit sounds to high frequencies
how can animals whose muscles can twitch up to about 1kHz make higher frequency sounds and thus avoid short circuiting
use frequency multiplier
ex: cicadas
how do cicadas use frequency multiplier
tymbal muscles vibrate at high resonance frequencies
which of the follow statements is correct
a. a fish swim bladder can act like a sound monopole
b. animals that are small can suffer from the problem of acoustic short circuiting
c. to generate higher sound frequencies, animals can use a frequency multiplier
d. all of these statements are correct
d
what is source driven
sound producing structure is not substantially influenced by the surrounding air
-air is low pressure
-not enclosed
what is response driven
sound producing structure is substantially influenced by the surrounding air and structures
what is the fundamental frequency
the frequency component of the note, that is the lowest common integer multiple of the harmonics
what is f0 determined by
the inherent resonance properties of the sound generator
