Band Compress; Stereo Algorithm To Compress A Single Frequency Band; Band Compress Filtering At Full Compression - Kurzweil K2661 Musician’s Reference Manual

KDFX Reference
KDFX Algorithm Specifications

948 Band Compress

Stereo algorithm to compress a single frequency band

PAUs: 3
Band Compress is in most respects identical to SoftKneeCompress. However, Band Compress
compresses only on a single band of frequencies. Frequency band selection is based on a parametric filter.
You control the filter center frequency and bandwidth. The compressor controls the filter gain.
Figure 99
The compressor reduces the signal level when the signal level exceeds a threshold. The amount of
compression is expressed as a ratio. The compression ratio is the inverse of the slope of the compressor
input/output characteristic. The amount of compression is based on the sum of the magnitudes of the left
and right channels. A compression ratio of 1:1 will have no effect on the signal. An infinite ratio, will
compress all signal levels above the threshold level to the threshold level (zero slope). For ratios in
between infinite and 1:1, increasing the input will increase the output, but by less than it would if there
was no compression. The threshold is expressed as a decibel level relative to digital full-scale (dBFS) where
0 dBFS is digital full-scale and all other available values are negative.
With Band Compress, the side chain processing acts only on a specified band of frequencies. At the input
of the side chain is a bandpass filter which passes only the frequency band of interest. The side chain
output then controls the gain of a band cut filter acting on the main signal path. The bandpass and band
cut filters both are set to the same center frequency and bandwidth which you control. The depth of the
band cut filter is of course set by the compressor side chain processing.
You can select which channel, left (L), right (R) or the maximum amplitude of the two (L & R) is used to
control the compression (side chain processing) with the SC Input parameter. You can also select which
channel is actually compressed, again left (L), right (R) or both (L & R) using the ComprsChan parameter.
10-192
Gain
0 dB
- 20
- 40
10 Hz
Band Compress filtering at full compression
100 1000 10 k
Freq