It includes the following features:
- Input gain control (+/- 20 dB)
- Expansion threshold down to -40 dB
- Expansion ratio from 1:1 to 10:1
- Attack and release controls
- Sidechain input gain trim
- Sidechain 12 dB/oct high-pass filter
- Side chain 'listen' option with metering
- Option external sidechain input
- Level meters for input and output
Although it is similar in operation to the Compressor, the signal flow of the Expander is closer to that of the Gate since it lacks the Makeup and Mix controls of the compressor:
In fact it can be useful to think of the Expander as a Gate, in which the signal below the threshold is reduced rather than blocked.
As with the Compressor and Gate the signal used to determine the gain reduction can be trimmed, filtered and monitored using the controls in the 'Sidechain' section. Activate the 'External' switch to use an external signal (from inputs 3 & 4) to control the expansion.