12.25

CHANNEL DYNAMICS COMPRESSOR & GATE1238
The Gate/Expander section
Gating or expansion will attenuate signals below a set threshold; the opposite of compression. It can be used to re-
duce or eliminate unwanted background noise that may be present when there is no signal to mask it. Gating is also
commonly used to reduce microphone “bleeding”, e.g. when recording a close-mic’ed drum kit you can use gating to
silence the tom microphones when the toms aren’t being played to tighten up the sound, and for special effects like
“keying” (see below).
Higher expansion ratios (10:1 and above) are referred to as noise gating, where the channel is completely silenced
if the level drops below the set threshold.
The Gate/expander has the following parameters:
On
D Click the On button to activate the Gate/Expander section.
Exp
In Expander mode, the Range (gain reduction) is not as severe as in Gate mode, but more gradual around the Thresh-
old. Also, the gain reduction is not attenuated by a certain dB but is scaled. The major difference compared to the
Gate function is that instead of muting the signal once it drops below the Threshold (gate), the Expander still lets
some signal through but at a lower level, resulting in a signal of lower volume. You could think of an Expander as an
“inverted” compressor, i.e., it expands the dynamic range of the input signal.
D Click the Exp button to change the operating mode from Gate to Expansion.
The Range knob (see below) then controls the expansion amount.
Hold
D Set the time the gate should stay fully open after the signal falls below the Threshold.
Hold interacts with the Release parameter such that Release only starts acting after the set Hold time.
Range: 0 ms to 4000 ms
Fast
The normal attack time for the Gate is normally1.5 ms per 40 dB.
D Click the Fast button to lower the attack time to 100µs (microseconds) per 40 dB.
This can be is useful for percussive material were the waveform rises steeply in a very short time.
Range
D Set the amount of gain reduction applied to signals below the set Threshold.
The Range can be set from 0 dB (no reduction) to -40 dB. If the Exp button is on (see above), the Range knob
controls the expansion amount.