User`s manual

107
Compression Region: In this region the output signal level changes at a fraction of
the rate of the increase of the input signal level. The dynamic range of the output
signal is thus is reduced with respect to the input signal. As an example, a 2:1
compressor would produce an output level change of only 10 dB when the input
signal changes by 20 dB. Compression allows signals of wide dynamic ranges to be
squeezed into more limited dynamic ranges of recording media and transmission
channels. Compression also eases listening, especially for noisy audio.
Compressors are generally preferred over AGC's since input signal level
differences are more modestly preserved.
Expansion Region: In this region the output signal has a wider dynamic range than
the input signal. Expansion is the opposite of compression. As an example, with
an expansion ratio of 1:3, the output signal will change by 30 dB with only a 10dB
change in the input signal. Expansion may be used to restore a signal's dynamic
range following compression; for example, if a 2:1 compression has taken place, a
1:2 expansion would restore the signal to its original dynamic range. Expansion is
also used to attenuate objectionable low-level background sounds that are below
voices.
Figure 4-63 Limiter/Compressor/Expander Control Window
Description of operation (Six different parameters are adjustable on the LCE Control Window:)
The Expansion Ratio can be adjusted through a range of 1:1 to 1:100 by using the scroll
buttons beside its text entry box, by entering the value in its text entry box, or by clicking
on the Expansion Ratio Curve using the mouse pointer and adjusting it to the desired
value. NOTE: Only the portion of the ratio to the right of the colon is specified.