Gates

Noise gates can be extremely handy tool for removing noise during pauses in an audio signal. Whether you are having issues with spill from other drums or instruments in a drum kit recording, or you are recording a guitar amp and want to avoid amplifier noise while the guitarist isn't playing, a noise gate can be just the tool you need. We have created the following guide to help give you an understanding of noise gates and some of the ways in which you can use them.

A noise gate belongs to the dynamics processor family of effects, along with compressors and limiters. Gates are similar in concept to compressors, except instead of turning down the loudest parts of the sound, they instead turn down the quietest parts of the sound. A noise gate automatically turns down the volume by a certain amount when the audio signal drops below a preset threshold, for example when the musician is not playing. One important point is that although a noise gate can be used to remove noise during pauses, it is not able to remove noise while the instrument is playing.

Noise gates are also good for more creative uses too, including shortening the decay time of drums and rhythmic instruments for a tighter sound, or cutting off the attack of a sound so that all you can hear is the decay. Like compressors, some gates are also able to be triggered by an external signal via a side chain input. This allows for creative effects such as feeding a bass signal through the noise gate, while triggering the gate with a kick drum signal via the side chain input, causing the bass signal to follow the envelope of the kick drum signal. This allows for all sorts of creative uses, limited only by your imagination.

Most gates share a fairly common set of controls, which we have outlined for you below:

• Threshold: The threshold control sets the audio level, below which the gate acts on the sound passing through it.
• Attack: The attack level determines how quickly the gate stops acting on the sound when the signal rises above the threshold level. The attack is typically measured in milliseconds.
• Hold: The hold time determines how long the gate will wait before acting on the sound when the signal level drops below the threshold level, typically measured in milliseconds.
• Release: The release time determines how quickly the gate will start to act on the sound after the hold time is up. Like the attack and hold time, the release time is usually measured in milliseconds.
• Attenuation: The attenuation level sets how far the volume level of the sound is brought down when the gate is acting on the sound.
• Flip: Some gates also provide a flip control, which turns the gate into a ducker. This means that instead of attenuating the sound when the signal level drops below the threshold, it affects the sound when the signal level rises above the threshold level.

Much like compression, there are two main ways to use gates, either subtly as a tool to remove noise during pauses in an audio signal, or as a creative tool to manipulate the sound signal itself. Like any effect we recommend spending some time experimenting with different gate settings to see what you can come up with.