Expander

 
Reduces the level of signals that fall below a threshold level.

Inputs and Outputs

The single channel expander has one audio input and one audio output.

The stereo expander is identical to the single channel version except that it has 2 inputs and 2 outputs. Adjustment of controls has the same effect on both channels.

Properties

Side chain

A side chain input can be made available so that an equaliser (for example) can be introduced to make expansion frequency conscious. Any side chain processing would normally derive its signal from the same source that is fed to the audio input of the expander.

Control Panel

Threshold control

• Adjusts the level threshold below which gain reduction will take place. Above this threshold no gain reduction will take place.

 

Ratio control

• Adjusts the aggressiveness of expansion.

Attack control

• Adjusts the time it takes for the expander to recover after the signal level goes above threshold.

Release control

• Adjusts the time it takes for the expander to respond to signal levels which fall below the threshold.

Bypass button

• Removes the expander from the signal path.

Gain Reduction meter

• Displays the amount of gain reduction being applied.

 

Notes

! The expander can cause distortion at low frequencies when the Release control is set to low values. Unless you particularly need the expander to attenuate very quickly when the signal falls below threshold, set the Release control to a reasonably high value.