A noise gate only allows signal above a specified threshold to pass. If a signal’s amplitude is below a set threshold, then no signal is allowed to pass. A noise gate is used when the level of the signal is greater than the level of the noise, but the level of the noise is above an acceptable level. For example, when mic-ing a kick drum for a recording, the microphone will pick up the kick drum beater, but it will also pick up the rest of the kit. A gate can be used to eliminate the extraneous noise of the entire kit so that only the kick drum is heard in the recording.
