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A noise gate is a form of dynamics processing used to increase dynamic range by lowering the noise floor, and it is an excellent tool for removing hum from an amp, cleaning up drum tracks between beats, background noise in dialog, and can even be used to reduce the amount of reverb in a recording.
The common parameters for a noise gate are:
Threshold – sets the level that the gate will open, when the signal level drops below the threshold the gate closes and mutes the output.
Attack – how fast the gate opens.
Hold – how long before the gate starts to close.
Release – aka decay, how long until the gate is fully closed again.
Range – how much the gated signal will be attenuated.
Sidechain – for setting an alternate signal for the gate to be triggered from, sometimes called a Key.
Filters – the filters section allows you to fine tune the sidechain signal.
What’s It For?
The normal use for gating is for removing background noise. An essential tool for clean dialog recording.
Some other uses for gates are gated reverb and using the sidechain to activate other effects.
How To Set A Noise Gate
To setup a gate properly, start with the the attack, hold, and release as fast as possible. Set the range to maximum, and the threshold to 0 dB.
Start lowering the threshold until the sound starts to get chopped up by the gate. Slow down the attack time to remove any unnatural popping. Adjust the hold and release times to get a more natural decay.
If you don’t want the background noise to be turned down as much then you can reduce the range control.
Gated reverb was a popular effect in the 80s, mostly because of Phil Collins records.
To set it up, take your drum tracks and send them to a stereo reverb with a large room preset. After the reverb, insert a stereo gate. Adjust the gate settings so that the reverb is cut off before then next hit.
In this example you’ll hear the unprocessed drums, then with reverb, then adding the gate. (Listen)
The classic Drawmer DS201 is a hardware noise gate that is hard to beat.
The gate on the Waves SSL E-Channel is good, simple and effective.
The free ReaGate VST is quite good as well.
Noise gates aren’t very much fun to talk about, but they are a powerful tool that you need to know how to use.