Chapter 1-9 Flashcards
Waveform
a continuous line showing air pressure or voltage over time
Axis
fixed reference line for the measurement of coordinates
cycle
wave displacement from equilibrium to max to min and back
phase
the measure of a starting waveform compared to another waveform or reference point
Compression
increase in air pressure caused by the displacement of air molecules
rarefaction
decrease in air pressure caused by the displacement of air molecules
period
the amount of time required for a waveform to complete one cycle
frequency
the number of waveform cycles occurring each second
pitch
subjective perception of frequency
What unit is frequency measured in
cycles per second (Hertz)
amplitude
the measure of the size of displacement
loudness (volume)
perception of amplitude
spectrum
the measure of all frequencies and their amplitudes in a sound
timbre
subjective perception of the spectrum of a sound
sympathetic vibration
when something resonates because it has matching resonant frequencies with something else
simple waveform
waveform with only one frequency component
complex waveform
waveform with more than one frequency component
fundamental
the lowest frequency in a complex waveform
natural number
positive integers
harmonic
a frequency which is a positive integer multiple of the fundamental frequency
overtone
harmonic occurring above the fundamental
partial
any frequency occurring in the spectrum
speed of sound
344 m/s @15 degrees C
What is the symbol for wavelength
lambda
node
a point on a waveform with minimum displacement
antinode
point of a waveform with maximum displacement
onset
the beginning point in time of an event
envelope
a description of how a parameter changes over time
attack
the time that it takes from the onset of a sound to grow to its loudest point
decay
the time that it takes for a sound to fall from its maximum level to its sustain level
sustain level
the measure of the constant amplitude of a sound following the decay
sustain duration
the portion of the envelope where the amplitude is nearly constant
release
the time that it takes for a sound to fall from the sustain level to zero
ADSR
abbreviation for a common envelope
resonance
the tendency of an object or enclosed space to amplify or aphasia acoustic energy at a particular frequency or frequencies
eigentone
the resonant frequency of an enclosed space or anject
standing wave
a wave where each point has an unchanging amplitude raging from zero at the nodes to a maximum at the antinodes
absorption coefficient
the measure of the attenuation or reduction in the energy of a waveform striking the material
reflection
the unabsorbed sound energy that is thrown back from a surface
echo
a duplicate of a sound energy that is thrown back from a surface
reverberation
occurs when a multiple copies of a sound overlap so that each onset is not distinct
reverb time
the time is takes for a single sound to drop 60 dB in intensity
Helmholtz resonator
any enclosed space with rigid walls that supports eigentones
bass trap
an enclosed space that is designed to resonate at and reduce the energy of specific frequencies
formants
areas of emphasized frequencies in a sound spectrum
fast Fourier transform
a method of analyzing complex sounds to examine their frequency content