The problem with mixing music is sometimes you get too much sound coming through your system. I’m not talking about sound volume, I’m talking about unwanted sound, sound that’s not beneficial to your mix. But how can you eliminate unwanted sound? This is where gating comes into play. Audio gating enables you to control when sound enters your system and when it leaves.
Two Primary Benefits of Gating
Benefits in your mix can be gained using gating in two areas;
- Removing secondary sounds from a microphone. You might think of this as spill or leakage. Breakout the hazmat suits, we have a spill on the stage! I’m talking about a microphone that picks up the sounds of another instrument other than the one which is intended. For example, when the drum toms aren’t being played, they will likely pick up the sounds of other drum kit pieces. Of course, it wouldn’t be as loud of a sound that’s broadcast but it is an additional sound source adding in an unnecessary sound, a sound that can even negatively affect your mix because of the added volume and frequencies.
- Reshaping the sounds coming from the microphone. Gating allows you to control the volume level in which sound passes out of the mixing channel. Gating also allows you to control the point in which the volume stops coming out of the channel. Imagine controlling the sound of a snare drum. You could use gating to give it a quick attack (a hard and fast start) but then allow it to decay naturally. Or, you could do the opposite. With the right amount of gating changes, you could even produce a completely unnatural sound from the snare drum…and it just might be right for the song.
A Problem with Gating
Musicians could play their instrument quieter as part of the arrangement. For example, a soft hit of the toms could be part of the first verse. If your gating is set with a low threshold, then your system might be gating out those toms and not broadcasting them. It’s times like this where digital mixers with scenes are a great way for setting different gating structures per song.
The controls (parameters) for controlling gating are very similar to those used in compression.
The audio gate is closed (no sound coming through) when the audio volume is below the threshold. The gate is open when the sound exceeds the threshold. Don’t think that you can easily set the threshold. Much like mentioned in the problem with gating, musicians play instruments at different volumes, especially instruments where gating is helpful, like drums. Therefore, the threshold you set for an instrument, like a snare, might need to allow the drummer a bit of room for natural volume differences in their playing.
Did I mention the gates don’t complete mute the sound. Consider these as picket-fence gates. The gates actually attenuate the sound by the degree specified in the range setting. The range defines how much the sound is reduced below the threshold. For example, you can set the range to -20 dB for a gate.
WHY DOES IT HAVE TO BE SO COMPLICATED!?!
I’m glad you asked. The problem with completely muting certain sounds is they then lose their natural sound. For example, if you had such muting, it’s possible your mix would sound like a group of instruments and singers abruptly starting and stopping. Unnatural.
Attack controls how quickly the gate opens, how quickly it lets the sound through. You use attack to control how quickly the sound enters into your mix after the gate is open. The attack greatly affects how the instrument or vocal sounds entering into the mix.
Release controls how quickly the gate closes. Consider this the rate of controllable decay.
The last of the parameters is called Hold. And this is where the art and science of mixing really come into play. The hold time controls how long the gate stays closed, once it’s closed. For example, you can set the hold so that even if the threshold is reached again, the gate stays closed until a certain amount of time passes. The benefit of the hold parameters is allowing a natural decay to occur before the sound is allowed to come back in again. I’m not saying you always want to use a high hold time, but it is yet another control you have over shaping the sounds going out of your system.
You can see all of these in this chart of how gating would affect incoming audio;
Image by Iainf
The Take Away
Gating is another way of shaping and controlling the sounds in your mix, just like reverb, delay, and compression. It’s a great way to get a better sound from your drums and even your vocalists. Try it out and see what it can do for you.
Looking for a COMPLETE GUIDE TO GATING?
Check out my free Ten-Minute Guide to Audio Gating.
*photo provided by bcpaterson.