pressure correct answers sound travels as _______ fluctuations
elastic, compression, rarefaction correct answers acoustic medium is _____, which allows particles to crowd together and move apart:
_________ = region in a longitudinal wave where the particles are closest together
__________ = region in a longitudinal wave where particles are further apart than they would
be at atmospheric pressure
no, sine, constant correct answers are all waves periodic?
_______ waves = another name for simple periodic waves = periodic oscillations of _______ amplitude
frequency, amplitude, phase, period correct answers 3 properties needed to define a sine wave:
1) _____________ = how many cycles a wave completes per unit time (how fast)
2) ____________ = peak deviation of a pressure fluctuation from normal atmospheric pressure (how big)
3) _______ = timing of the waveform relative to some reference point (when/with what delay?)
*note: the __________ = the duration of one cycle or the time it takes for a wave to complete one cycle
greatest common denominator correct answers how do you find the fundamental frequency of
a complex periodic wave (one composed of at least 2 sine waves)?
Find the ____________
100 Hz correct answers If a complex wave has 400 Hz and 500 Hz components, what's the fundamental frequency?
frequency, amplitude correct answers a power spectrum plots ___________ on the x-axis and
____________ on the y-axis
Fourier, frequency correct answers ____________'s theorem = says any complex wave can be decomposed into a set of sine waves having particular frequencies, amplitudes, and phase relations
(_______ analysis of a complex wave yields a power spectrum of its components)
*replaces time on the x-axis with ________ to display components)
flat, equal correct answers what does the power spectrum look like for white noise?
a relatively ______ spectrum, because white noise has nearly ______ amplitude for all possible frequency components aperiodic, white noise, transient, impulse correct answers ________ waves = those with random waveform or a non-repeating pattern
example: /f/ or /θ/ sound (fricatives = made by turbulent airflows)
examples:
1) _______________ = sound characterized by random pressure fluctuations
2) ____________ = bursts which produce sudden pressure fluctuations that aren't sustained or
repeated over time (ex: door slam, balloon pop, etc.)
a.k.a a(n) ________________ = energy only at one point in time
sudden peak in amplitude at one point in time, perfectly straight horizontal line at a single amplitude correct answers What does the waveform of a transient signal (impulse) look like?
The power spectrum?
f = 1/T correct answers What's the equation for frequency, given the period of a wave?
low-pass, high-pass, band-pass, band-stop, pass, reject, bandwidth, center correct answers types of acoustic filters:
1) ____________ filter = passes or blocks high frequency components of a wave, and lets low frequency components through
2) _____________ filter = allows high frequency components through
3) __________ filter = most common in the real world; has two cutoff frequencies that allow a specific range of frequencies through 4) _______ filter = has a range of frequencies that are purposely blocked
_______ band = frequency band allowed by a filter
________ band = frequency range blocked by a filter
________ = width in Hz of the filter's peak, such that one half of the acoustic energy in the filter is within the width
________ frequency = ideal frequency to be let through the filter
1000 Hz correct answers If a low-pass filter with cutoff frequency 300 Hz is applied to a complex wave with components of 100 Hz and 1000 Hz, which is blocked?
half correct answers Considering the total area under the curve of a filter shape, the bandwidth = the range around the center frequency that encloses _______ of the total area
less steep correct answers the slope of a filter becomes (steeper/less steep) as bandwidth increases
sound, sound wave correct answers _____ = pressure fluctuation that we can hear
_______________ = traveling pressure fluctuation