A noise gate allows a signal above a certain selected threshold to pass through, known as an open gate. If the input signal falls below the threshold, the signal gets cut off and consequently no sound is heard, known as a closed gate.
Noise gates are usually used in the following situations:-
- Reduce background noise in a recording.
- Help eliminate leakage between instruments such as drums.
There is generally no benefit in gating sampled drums and instruments, as there is usually no noise present. Many digital reverb units allow the reverb to be gated.
Common controls on a noise gate include threshold, attack, release, hold and range.
The threshold sets the level at which the gate opens and closes.
The attack determines how quickly the gate opens. Measured in milliseconds
The release determines how quickly the gate closes. Measured in milliseconds
The hold control determines how long the gate is kept open for after the signal falls below the threshold level, and helps to ensure that a decayed proportion of a sound is not cut off.
The range control turns a signal down that is under the threshold instead of muting it completely.