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Gates Gates are easy to explain - A gate is a little man in a box with a mute button. As long as you're making noise, he leaves you alone. As soon as you get quiet or step away from the mic, he mutes you. It works the same for guitars, drums, vocals, or anything. The little man in the box draws a line called the threshold. As long as your audio is above the threshold, your channel is left alone. As soon as you drop below the line, he turns you off. Some nicer gates have features like a release control. With a release control, instead of simply muting you immediately, he will fade you out smoothly. He can fade you out slowly or quickly depending on how you set him up - specifically - how you set your release control. For example with drums, you set the threshold high so that until a drum is hit, the channel remains off. As soon as the drum is hit, the gate opens, we hear the drum, it falls back below the threshold, and the gate turns the channel back off until the next time the drum is hit. This keeps the drum from ringing through the entire performance, thus cleaning up our mix. We only hear the drum when it is hit thanks to the gate. Gate parameters: Threshold - This is the volume or level at which the gate is triggered. You set it so that background noises you don't like - are below the threshold, and what you DO want, is above the threshold. That way, the gate only opens for what you DO want. Attack - How fast should the gate open? Should it fly open immediately, or should it open slowly and fade something in for you? You decide with the attack knob. For drums you want the attack as fast as possible so the gate doesn't cut off the beginning of the drum. For vocals you want it to fade in over a few milliseconds - probably between 20ms and 100ms. 100ms is 1/10th of a second. Hold - After the gate opens, it won't even look at the release control until it has waited a little. You hold the gate open. If the gate opens, and you have the hold knob set at 2.5 seconds. The gate will remain completely open for 2.5 seconds regardless of what the audio is doing. Then it will go back and check to see if the signal is above the threshold. If it is, the gate stays open. If not, it will move on to the release control where the gate is released and begins to close. Hold is a nice feature not found on cheaper gates. It can keep a gate from opening and closing too fast - "machine gunning". Release - How fast or slow should the gate close? Well it depends on what you're gating. Most sounds have a natural decay. For example when you strike a drum, it takes a second or two to fade most of the way out. If you set your gate to close too fast, it would chop off the natural decay of the drum, and it wouldn't sound good. You can set your release control so that the gate fades out with the natural decay of the instrument you're gating. That way, nobody notices the gate is there. Ratio - This is how far down the volume is reduced when the gate is closed. Instead of completely muting the channel it is possible to only reduce it by 10db or 12db or whatever you want. Just set the knob. Cheaper gates won't have this feature - they just mute the channel all the way off. Some gates are frequency dependant. This is a nice feature to have in very noisy environments like rock 'n roll stages during a concert. A gate that is frequency dependant can be tailored to respond only to a certain frequency range. For example. Let's say we are gating a tom tom, but there is a very loud bass rig 3' away. If the drummer is a soft hitter, then the bass rig is always louder than the drum. This means that the bass guitar will keep the gate open and we can't really gate the drum at all. So let's use our nice frequency dependant gate to solve this problem. Set up the gate so that it only responds to the frequencies present in the drum, but ignores the lower bass frequencies coming from the bass rig. It will also ignore the really high frequencies coming from the cymbals. The gate won't change the sound of the drum in any way, it just ignores certain unwanted frequencies. This is called a key. You have to have a key to open a gate, right? Your key is the frequency range you tell the gate to respond to. Be careful of gating too hard. If you set your threshold too high, the sound you want, might not be able to open the gate. Also be careful of gating things that have a lot of background noise around them. Gating drum toms is a good idea if you are careful not to gate too hard, but one issue that can happen is this - If you gate a tom tom that is right next to a cymbal (for example), and the cymbal is ringing at the same time the tom tom is hit, the tom gate opens and the cymbal suddenly gets louder. This was not the plan, but it's life. Microphones don't pick up just what we want - they pick up other things nearby. This is where art meets the science of audio engineering. Does it sound better with or without the gate? You decide. Practice using gates in many situations. Know your equipment and its limits. Do what sounds best to you.
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