As its name implies, a noise gate (often just called a “gate” for short) reduces or mutes low volume signals that can contain a significant amount of noise. In live sound, gates are typically used to turn down inputs that aren’t being used, so they can improve the performance of your PA system. By lowering (or turning off) microphones that aren’t needed in the mix, the system is better able to amplify without feedback. The rule “less open microphones equals more volume before feedback” is one to live by!
Gates were originally outboard gear that had to be physically inserted into the channel you needed to turn down (this was done by literally plugging in a patch cord). These devices had to be racked up near your console so you had easy access to all the controls, and they were fairly costly too.
Today, most digital consoles (including all models made by Yamaha) provide a gate on every input, so getting good results is way faster and easier than it used to be. In addition, you can save your gate settings (as well as all other settings) on the console, allowing them to be instantly recalled.
Here’s the basic gate page provided by Yamaha TF Series consoles:
Let’s take a closer look at each of these controls:
There’s also both input and output metering. The meter under the GR (for “Gain Reduction”) output shows the amount of attenuation the gate has applied to the signal.
Since gates use VCA (voltage-controlled amplifiers) or, in the case of digital consoles, DCA (digitally controlled amplifiers), they add no color at all to the sound, which allows them to adjust level only. Very stealthy…
Here’s an example of how to use gating on drums. A floor tom commonly resonates in the lower midrange EQ region and when it is not being played, those resonances can rumble throughout the entire performance, thus causing unwanted “decrease in gain before feedback.” Since damping the floor tom might color the sound, using a gate here will protect the integrity of the desired tone. Other toms can benefit from gating as well, since you can decrease the bleed or leakage of nearby drums into that input. Drums have a fairly fast attack, so you should set that accordingly on your gate. In practice, lower frequency drums require a longer release time than, say, a high rack tom.
Another place where gates are very helpful is background vocals, where the backing singers often sing just parts of the chorus and not the rest of the song. Applying a gate here will help keep the main vocal more prominent in the overall mix. Gates applied to vocals should have a slower attack setting than those used with drums, and rather than a sharp attenuation, sometimes just 10-15 dB can be very helpful.
There are also times not to use gates. Don’t use them on:
Remember also that gates are level-dependent, so if the ones used on drums are set for a hard playing rock style song, and for the next tune the drummer uses brushes on a ballad, you’ll need to adjust accordingly. This is a lesson I learned the hard way!
Click here for more information about Yamaha TF Series consoles.