Extron Electronics DMP 64 User Guide - Manual (Page 53)

Compressor
The compressor regulates signal level by reducing (compressing) the dynamic range of the
input signal above a specified threshold. The input level to output level ratio determines
the reduction in the dynamic range beyond the threshold setting. For example, with a ratio
setting of 2:1, for every 2 dB of input above the threshold, the compressor outputs 1 dB.
Compression is commonly used to contain mic levels within an acceptable range for
maximum vocal clarity. A compressor can also make softer sounds louder in one of two
ways. The dynamic range can be reduced by compressing the signal above the threshold
while raising the post-compressor gain/trim (referred to as "make-up gain"). Alternately,
the input signal can be increased while the compression ratio above the threshold is
increased correspondingly to prevent clipping. Both techniques have the effect of making
louder portions of a signal softer while at the same time increasing softer signals to raise
them further above the noise floor.
Compression can also be used to protect a system or a signal chain from overload similar
to a limiter. Click in each field to change the value.
Threshold — The input signal level above
which compression begins (subject to attack
time) and below which compression stops
(subject to hold and release time).
The threshold level can be adjusted from
-80.0 to 0.0 dB in 0.1 dB increments.
Default is -30.0 dB.
Ratio — The input signal level reduction
when compression is engaged.
Ratio can be adjusted from 1.0 to 100.0 in
0.1 increments.
Default is 2.0:1.
Attack Time — Adjusts the time delay for
compression to engage after the input signal
level reaches or exceeds the threshold level.
Attack time can be adjusted from 0.0 to
200.0 ms in 0.1 ms increments.
Default is 5.0 ms.
Hold Time — Adjusts how long compression
continues after the input signal drops below
the threshold and before release time begins.
Hold time can be adjusted from 0.0 to
500.0 ms in 0.1 ms increments.
Default is 100.0 ms.
Release Time — Adjusts the time it takes to return the signal to normal (unprocessed)
levels after the signal no longer exceeds the threshold level setting. Release time begins
only after hold time is reached.
Release time can be adjusted from 10 to 1000.0 ms in 0.1 ms increments.
Default is 100.0 ms.
Soft Knee — Select the
Soft Knee checkbox to smooth and soften the transition from
uncompressed to compressed output levels. There are no adjustments.
DMP 64 • Software Control 47