Audio Gate

Introduction

A gate is used to prevent sound lower than a certain volume (threshold) from being heard. This can be useful in preventing background noise from coming through a mic when someone is not using it, or as a last resort for minimizing annoying buzzing in a channel. Check out this short video going through gates:

Audio Theory - Gate

Important Terminology

• Threshold: This is the level at which the gate will "open". For example, if you have your threshold set to -30db, anything under that would not be heard, but when you move above the threshold, the gate will open and allow audio through. In this case, a signal at -35db would not be heard, but -20db would be heard.
• Attack: This is the time it takes for the gate to fully open after the incoming signal exceeds the threshold. A fast attack time will open the gate almost immediately, which is useful for percussive sounds. A slower attack time can create a more natural fade-in effect.
• Hold: This is the amount of time the gate remains open after the signal falls below the threshold. The hold time helps to prevent the gate from closing too quickly, which can create a more natural sound by allowing short pauses in speech or music to pass through without being cut off. Most helpful for speaking. Use sparingly.
• Release: This is the time it takes for the gate to close after the hold time has elapsed and the signal is below the threshold. A longer release time can make the gate close more smoothly, reducing the chance of abrupt cuts in the audio.
• Detector - Lowpass/Highpass: These are filters that can be applied to the incoming signal before it reaches the gate's detector. A lowpass filter allows frequencies below a certain point to pass through, while a highpass filter allows frequencies above a certain point to pass through. By using these filters, you can make the gate more responsive to specific frequency ranges, which can be useful for targeting certain types of noise or for emphasizing certain elements in the audio. For example. If you lowpass down to 100hz on a kick drum, the gate will respond to sound below 100hz. This would be helpful in gating a kick drum so that a crash of a cymbal wouldn't open it, but when they kick the kick drum it would open the gate.