The basic concept of a gate is the same, whether we’re talking about an expensive piece of outboard gear or an affordable software plug-in. A gate closes (in other words, “gates”) and silences the signal once it reaches a threshold, usually to reduce (or eliminate) noise — you can think of it as an automatic volume control that turns off once the signal crosses the threshold. A gate belongs to the same family of dynamics processors as compressors or limiters and conceptually operates in similar fashion. Gates are often used to control bleed among mics when recording multiple instruments simultaneously or when multi-miking a drum kit. They’re also commonly used to gate out hiss, hum, or rumble that might inadvertently end up in a track.
But being simple in concept doesn’t mean that gates don’t lend themselves to interesting and sonically adventurous applications. Here are six creative ways to use gates beyond the traditional application of controlling or removing noise.
Creating Fade Outs with Gates
The standard use of gating is to close down the audio signal as soon as that signal drops below the gate’s threshold. However, many gates offer a release control, which determines how quickly or slowly the gate closes down to silence. If you set a long release, the gate will close slowly, and vice versa. You can use this technique to make gating sound more natural, with a slow drift to silence rather than an abrupt cutoff, or you can use it as an effect, letting your audio trail out as a sort of “fade out” effect. Start with the release low, and increase it until the gate closes when you’d like the fade to end. The maximum release control on many gates is fairly long — up to two seconds, or even more — so you can create fade outs that last for very long times.
Using Gates as Transient Designers
Here’s a fun technique. Let’s say that you want to shape the attack peaks, or transients, of a signal. Set the threshold of your gate to allow the peaks to pass through. To do this, start with the threshold turned all the way up so no audio gets through — the gate is always closed, regardless of the signal entering it — then reduce the threshold until just the transients get through. Use the gate’s release and attack controls to set how quickly the gate opens up and shuts down around the transient. Congratulations, you have turned your humble gate into a transient designer! Combine this transient-only track with a copy of the track that has the natural (un-gated peaks) sound, and blend to taste to add sparkle and increased attack and articulation.
Make Your Own Gated Reverb
If you love big ’80s-style drums, then you probably know that the popular gated reverb effect was an important part of that era’s sounds — that big, prominent reverb that suddenly cuts off. (Check out just about any Phil Collins or Genesis track from the ’80s, a prime example being “In the Air Tonight,” when the big drums enter around the 3:20 mark. Another example can be found in Michael Jackson’s “Bad,” which uses a more electronic-sounding snare.) With a gate, you don’t need to rely on a gated reverb preset on your favorite plug-in, which may not allow detailed control over the gate’s characteristics — you can turn any reverb into a gated reverb. Here’s how to do it: set your snare drum track to feed a reverb on an aux send/input. Set the reverb for a dense reverb effect, somewhere in the 600ms–800ms time length and set it to 100% wet. Use the aux input’s fader to mix the reverb level to taste with the dry snare sound. (In the ’80s, the reverb would have been loud!) Now insert a gate after the reverb. Set the gate’s threshold high so it will clamp down on the reverb while the signal is still loud, and adjust the attack and release so you get as much of the reverb tail as you want before the gate closes. For even more detailed control over the gate in this application, you could use the gate’s sidechain input to control when the gate opens and closes, which leads directly into our next tip!
Using Gates to Lock Timing
If your gate has a sidechain input, then you can chain (control) the opening and closing of the gate to a signal that is being monitored through a side input (hence, “sidechain”). This is a great way to lock one part to another. For example, if you want to tightly lock a bass part to a kick drum, place a gate on the bass track. Set the gate’s sidechain input to listen to the kick drum track. Set up this way, the gate will open and close when it detects that the kick drum is being struck — when the kick hits, the gate opens and you hear the bass. Adjust the gate’s attack and release control to taste to shape the envelope of the bass. This is a great way to tie gating to an instrument so that the two instruments are sounding in perfect lockstep with each other. But we’re not done with our gate’s sidechain yet — read on!
Rhythmic Gating Patterns for Synths and Vocals
Your gate’s sidechain can be used for more than just locking two instruments together. The audio that you use for the sidechain can be a special track that may not even be an audible part of your song but is just designed to function as a sidechain trigger. This technique can be used to achieve unique rhythmic patterns. This is a great way to create sequencer-like effects on sustained synths, stutter effects for vocals, rhythmic tremolo effects, and more. Here’s how to do it: create a track that has the rhythm that you want to use for your pattern using a drum instrument (or load up an appropriate drum or percussion loop). Again, you may not even want to hear this track in the final mix, so the rhythm could be played on a snare sound, a tom sound, a kick sound, or even using just a click sound. It doesn’t matter, since we’re only going to use it as a trigger for our gate. Set up a sustaining keyboard pad on another track. Insert a gate on the pad track. Feed the rhythm pattern or loop you created into the gate’s sidechain input. Adjust attack and release to taste. Now, when the rhythmic pattern or loop plays, it will trigger the gate to open and close in perfect sync, turning the sustained pad into a pulsating, chopped rhythm instrument.
Hold Off the Gate
There may be times when you don’t want a gate to clamp down if the signal briefly or occasionally drops below the threshold, such as on a part with significant volume drops on a few of the notes. Many gates have a parameter that’s perfect for this: the hold control. At first blush, you might think of this as a “sustain” control, but that’s not quite what a hold control does. Hold prevents the gate from operating for a set amount of time once the hold function has been triggered. In other words, when the input signal drops below the threshold, the hold function is triggered and the gate will wait for that period of time before it shuts down. When the hold time passes, if the signal is still below the threshold, the gate will then close. But if the signal has risen back above the threshold, the gate will remain open. For rhythmic parts, this is perfect — set the hold time longer than the duration of the softer notes, and when those notes trigger the gate, the hold function will keep the gate from clamping shut.
As you can see, you can get a lot more out of a gate than simple noise suppression. If you have any questions about what type of gate is best for your application, call your Sweetwater Sales Engineer at (800) 222-4700.