Compressor

Parameter Name

Parameter Range

Parameter Definition

Enabled

Enable/Disable

Enables or disables the DSP feature.

Threshold

-60 – 6 dB

The threshold control sets the level at which the compression effect is engaged. It will be compressed only when a level passes above the threshold. If the threshold level is set at say -10 dB, only signal peaks that extend above that level will be compressed.
The rest of the time, no compression will be taking place.

Knee

0 -20 dB

The knee is assigned as a numerical value yet can be described as qualitatively: soft, hard, or somewhere in between. The hard knee curve shows a sudden change in slope (ratio) that begins at the threshold. The soft knee curve, in contrast, shows a more gradual change.

Ratio

1-100 (n:1)

Specifies the amount of attenuation applied to the signal. A ratio of 1:1 (one to one) is the lowest and it represents unity gain, or in other words, no attenuation.
These compression ratios are expressed in decibels so that a ratio of 2:1 indicates that a signal exceeding the threshold by 2 dB will be attenuated down to 1 dB above the threshold. A ratio of around 3:1 is considered moderate compression, 5:1 would be medium compression, 8:1 starts getting into strong compression and 20:1 thru infinity to one would be considered limiting by most and can be used to ensure that a signal does not exceed the amplitude of the threshold.

Release Time

0 – 1000 second

It is the time it takes for the signal to go from the compressed "or attenuated" state back to the original non-compressed signal. Release times will be longer than attack times, ranging anywhere from 40-60 ms to 2-5 seconds, depending on which unit you are working with. Typically, release time should be set as short as possible without producing a "pumping" effect, which is caused by cyclic activation and deactivation of compression.