Chapter 2
Hertz
the unit of frequency, equal to one cycle per second
attack-release envelope (AR)
vibrating "struck" or "plucked" instruments where vibrations damp naturally.
threshold of hearing
0 dB
beat detection
the analysis of transients as a pattern of beats and bars is a standard feature in many recording programs
Frequency
the number of complete wavelengths that pass a point in a given time
sawtooth wave
- Contains every harmonic (even and odd) - Each harmonic is attenuated by 1/2, 1/3, 1/4, 1/5... in amplitude
threshold of pain
120 dB
Loudness
A sensory characteristic of sound produced by the amplitude (intensity) of the sound wave
Rhythm
A strong, regular, repeated pattern of movement or sound.
Square Wave
An almost instantaneous rise and decay of voltage or current in a periodic pattern with time and with a constant peak value. symmetrical. series of odd harmonics.
shepard tones
An illusion in which a series of tones appears to rise endlessly, but never leaves a relatively narrow range of frequencies
transient patterns
Aspects of rhythm can be seen in the waveform view by identifying patterns in the attacks of the notes
ADSR
Attack, Decay, Sustain, and Release are the four parameters found on a basic synthesizer envelope generator, and they match the physical attributes of naturally occurring sound.
amplitude envelope
Change in loudness over time of a musical note. Conventionally divided into attack, decay, sustain, and release segments (ADSR). a reduction of the amplitude profile of a sound with time on the horizontal axis, and relative loudness of the signal on the vertical.
ultrasonic
Describes a sound of a frequency too high to be heard by the normal human ear---above 20,000 hertz
Amplitude
For a wave or vibration, the maximum displacement on either side of the equilibrium (midpoint) position; height of the wave; deviation of air pressure.
Infrasonic
Sound waves with frequencies below 20 hertz
Triangle Wave
Symmetrical triangular shaped wave containing odd harmonics only, but with a lower harmonic content than the square wave.
Phase Cancellation
Two inverse waves combined together to cancel out to zero amplitude (no sound).
waveform view
a graph of the change in air pressure at a particular location over time due to a compression wave
temporary threshold shift
a temporary hearing loss after being exposed to loud noise that affects the functioning of the inner ear
pitch
a tone's experienced highness or lowness; depends on frequency
Waveform
a visual representation of a sound wave
pulse wave
a wave that consists of a single traveling pulse
sine wave
a wave whose source vibrates with simple harmonic motion
noise
anything that interferes with, distorts, or slows down the transmission of information
articulation
change in loudness over time. accent.
period
frequency (Hz) can be determined by waveform view by measuring the amount of time the wave takes to complete a cycle. the period of the waveform is the measurement of this and and it is measured in seconds per cycle. "T"
Decibels of sound pressure level (dB SPL)
measurement of amplitude; loudness; volume
white noise
noise consisting of all audible frequencies in equal amounts. more intense waveform.
pink noise
noise whose lower frequencies are proportionally higher in amplitude than higher frequencies. more pleasing than white noise.
Timbre
quality of sound/tone/color. related to waveform and spectrum.
