SD-3A

Peak Reduction

Allows to set the compression amount.

Gain

Controls the amount of make-up gain applied after compression.

Mix

Blends between dry and wet signals.

Limit/Compress

This toggle changes the character of the compressor. The Limit mode leads to more compression, and a punchier sound on transients.

High Frequency Filter

Internal side-chain filter that increases the sensitivity to high frequencies when turned to the left.

Stereo Link

When linked, the Left and the Right channels receive the same Gain Reduction, which is the average of the two signals. This can be used to control the stereo image of the output.

External Side-Chain

The SD-3A is a compressor with a variable threshold, set by the Peak Reduction knob. When using the External Side-Chain, the Side-Chain Gain slider will also affect the compression threshold; turning up the gain will have a similar effect to rotating the Peak Reduction knob clockwise.