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(compressor/decompressor) An abbreviation for the data compression schemes used by the ACM, AVI,
codec
MPEG, and QuickTime formats and the analog-to-digital converters on some sound cards. (Note that codecs only
compress file size; to compress audio amplitude, apply a compressor effect.)
An effect that reduces dynamic range by lowering amplitude when an audio signal rises above a
compressor
specified threshold. For example, a compressor can compensate for variations in level caused by a vocalist who
occasionally moves away from a microphone. Or, during mastering, a compressor can produce consistent levels for
full program material, providing a solid, professional sound for web, video, and radio presentations. (See "mastering"
on page 81.)
A fade from one audio track to another.
crossfade
D
(digital-to-analog converter) The hardware that converts a digital audio or video signal into an analog signal
DAC
that you can play through amplifiers and speakers.
(digital audio tape) A standard two-track digital audio tape format. DAT tapes are sampled at 16 and 24 bits,
DAT
and 32,000, 44,100, and 48,000 samples per second. (The latter is often described as DAT quality.)
(digital audio workstation) A computer system used to edit, process, or mix audio.
DAW
Decibels below full scale in digital audio. The maximum possible amplitude is 0 dBFS; all amplitudes below
dBFS
that are expressed as negative numbers. A given dBFS value does not directly correspond to the original sound
pressure level measured in acoustic dB.
Some sound cards record with a slight DC offset, in which direct current is introduced into the signal,
DC offset
causing the center of the waveform to be offset from the zero point (the center line in the waveform display). DC
offset can cause a click or pop at the beginning and end of a file.
In audio, the decibel (dB) is a logarithmic unit of measurement used for amplitude.
decibel (dB)
A time-shifted signal that you can mix with the original, nondelayed signal to provide a fuller sound or create
delay
echo effects.
Adds small amounts of noise to a digital signal so that very quiet audio remains audible when you convert
dithering
from a high-bit resolution to a lower one (for example, when converting from 32-bit to 16-bit). Without dithering,
quiet audio passages such as long reverb tails may be abruptly truncated.
Describes an audio signal without any signal processing such as reverb; the opposite of wet.
dry
(digital signal processing) The process of transforming a digital audio signal by using complex algorithms.
DSP
Examples include filtering with equalizers, and effects processing with reverbs and delays.
A storage medium similar to a CD, but with much higher bandwidth and storage capabilities. Audio in DVD
DVD
movies generally uses a 96-kHz sample rate and a 24-bit depth.
Audio amplitude range, from quietest troughs to loudest peaks. (See also "bit depth" on page 79 and
dynamic range
"decibel (dB)" on page 80.)
E
The process of increasing or decreasing the amplitude of specific audio frequencies relative to the
equalization (EQ)
amplitude of other audio frequencies.
Increases dynamic range by lowering amplitude when an audio signal falls below a specified threshold
expander
(the opposite of a compressor). For example, an expander can be used to lower the level of background noise that
becomes audible when a musician stops playing.
SOUNDBOOTH CS3
80
User Guide
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