Editing Noise gate (section)

==Controls and parameters==
[[File:Noise Gate Hysteresis.svg|thumb|400px|right|A noise gate without hysteresis can open and close undesirably with a fluctuating signal (top). With hysteresis, the noise gate does not ''chatter''.]]
Noise gates have a ''threshold'' control to set the level at which the gate will open. More advanced noise gates have more features.

The ''release'' control is used to define the length of time the gate takes to change from open to fully closed. It is the fade-out duration. A fast release abruptly cuts off the sound, whereas a slower release smoothly attenuates the signal from open to closed, resulting in a slow fade-out. If the release time is too short, a click can be heard when the gate re-opens.{{Citation needed|date=June 2008}} Release is the second-most common control to find on a gate, after threshold.

The ''attack'' control is used to define the length of time the gate takes to change from closed to fully open. It is the fade-in duration.

The ''hold'' control is used to define the length of time the gate will stay fully open after the signal falls below the threshold, and before the release period is commenced. The hold control is often set to ensure the gate does not close during short pauses between words or sentences in a speech signal.<ref>{{cite web |url=http://www.dbam.fr/matos/drawmer/ds201/user_ds201.pdf |title=Drawmer DS201 Dual Noise Gate Operator's Manual |access-date=27 July 2008}}</ref>

The ''range'' control is used to set the amount of [[attenuation]] to be applied to the signal when the gate is closed. Often there will be complete attenuation, that is no signal will pass when the gate is closed. In some circumstances, complete attenuation is not desired and the range can be changed.

Advanced gates have an external ''[[Dynamic range compression#Side-chaining|sidechain]]''. This is an additional input that allows the gate to be triggered by another audio signal. A variation of a sidechained noise gate used in [[electronic music]] production is a ''trancegate'' or just simply ''gate'', where the noise gate is not controlled by audio signal but a preprogrammed pattern, resulting in a precisely controlled chopping of a sustained sound.

Noise gates often implement [[hysteresis]], that is, they have two thresholds: one to open the gate and another, set a few [[Decibel|dB]] below, to close the gate. This means that once a signal has dropped below the close threshold, it has to rise to the open threshold for the gate to open, so that a signal that crosses over the close threshold regularly does not open the gate and cause [[oscillation|chattering]]. A longer hold time also helps to avoid chattering, as described above.