Noice gate

[laka97]

why we use NOICE GATE
and tell what happened after it used

[amagras]

https://en.m.wikipedia.org/wiki/Noise_gate

[albee1952]

Assume you mean noise gate? To really answer, I need to know what you are trying to accomplish. Here are some general guidelines I use:
1-I never gate an incoming signal(if the gate chops off something, its gone forever)
2-noise gates to solve buzzing guitars rarely works well(for me, anyway). I solve those by using an EQ and automating a lo-pass filter that starts at 20KHz, but ramps down to kill buzzing as the guitar(or bass) note dies down
3-noise gates on drums is probably the most popular use, but how well it works will depend a lot on the drummer and how hard they hit cymbals. If the crash cymbals open gates on toms, it sounds unnatural. In that case, I usually paste my own "one-shot" tom samples(mine are made with my house drums, but you could also use samples from others, drum VI samples, etc)

If you are not familiar with what a noise gate actually is, or does, I bet a search on youtube.com would find some great explanations. Basically, it passes no sound until the incoming audio reaches a certain loudness(adjusted with the "threshold" knob). If you insert a noise gate plugin on a snare or bass drum track and play with the settings, that will teach you a lot