3-58
Algorithm Reference
Band Compress
Figure 26
Band Compress block diagram
The soft-knee compressor is used which has a more gradual transition from compressed to unity gain.
Figure 27
Soft-Knee compression characteristic
To determine how much to compress the signal, the compressor must measure the signal level. Since
musical signal levels will change over time, the compression amounts must change as well. You can
control the rate at which compression changes in response to changing signal levels with the attack and
release time controls. With the attack time, you set how fast the compressor responds to increased levels.
At long attack times, the signal may overshoot the threshold level for some time before it becomes fully
compressed, while at short attack times, the compressor will rapidly clamp down on the level. The release
time controls how long it takes the compressor to respond to a reduction in signal levels. At long release
times, the signal may stay compressed well after the signal falls below threshold. At short release times,
the compressor will open up almost as soon as the signal drops.
For typical compressor behavior, the attack time is considerably shorter than the release time. At very
short attack and release times, the compressor is almost able to keep up with the instantaneous signal
levels and the algorithm will behave more like distortion than compression. In addition to the attack and
release times, there is another time parameter: SmoothTime. The smoothing parameter will increase both
L Input
R Input
Select
L, R or
Max L, R
Bandpass
Filters
Delay
Compressor
Computation
Delay
Notch
Filters
Select
L, R or
Max L, R
Bandpass
Filters
Filter Gain
Out
Gain
L Output
R Output
L, R,
or L&R
Compress
Channel
Out
Amp
In Amp
Threshold
