What do gates do?

S

steve134

New member
Hey,

The studio I'm going to be recording at soon has several gates listed under their equipment list. Does this mean that normal noises such as slight humming, feedback will not be recorded by the microphone, when recording electric guitar by micing the cab - when the gate is in use? Does the gate act as a filter to take out any unwanted noises that you wouldn't want in the finished guitar tracks?

The recordings I have heard from the studio I don't hear any amp hum, feedback, etc. in them and I was figuring that there was someway they weren't recording unnecesary sounds.

Thanks, any help would be appreciated.
 
a noise gate functions on audio the way a real gate functions, like on a fence. when the gate is closed, nothing gets through. when the gate is open, everything gets through. the threshhold sets the level (volume) at which the gate opens.
 
What more is there to add? Scrubs pretty much said what there is to say about gates. If you have trouble grasping what a gate does, wait till you encounter compressors.......
 
Haha ok cool.

So do professional studios use gates to get noise free guitar tones? Or are they just recording the amp when its at a low volume so feedback is greatly reduced?
 
remember,gates dont actualy reduce the noise,they stop the backround noise,but as soon as a person starts singing the gate opens and if there is a backround noise,it wil still get in.

so it only closes at the time when person is not singing.

And you thought it can do miracles? :D
 
Some gates also have ducking functions. My dbx 174 does. There are Drawmers that do too, as well as many others, I'm sure. Ducking is, in effect, reverse gating. Normally a noise gate is closed until a certain threshold is reached or an external input triggers it to open. A ducker, though, is normally open, and closes when the threshold or key input tells it to. An example of ducking in every-day action would be, for example, when a restaurant has background music playing, but must page waiting patrons. When the host speaks into the paging microphone, the background music gets much quiter or is muted completely until he is finished talking, at which point it returns to normal volume.

Another use would be as part of a gated reverb effect. The gate chops off the reverb tail before it decays completely. Nice if you are looking to achieve a 1980s cock-rock drum sound. Of course, as is required, I'll mention to listen to "In The Air Tonight" by Phil Collins for an excellent example of gated reverb.

Yet another popular way to utilize a gate is for a vocal effect in large, excellent sounding room (the key to successfully utilizing this technique). The vocalist's main microphone is placed in front of him at the usual distance of 6-12 inches or so. Another microphone is placed much further away, say 10 to 12 feet. This microphone is run through a gate. The threshold is set to open when the singing gets over a certain level, so if the singer has a very broad dynamic range, the quiter parts will sound much more intimate while the louder parts will sound more expansive due to the distant microphone opening the gate and capturing more of the room sound. I believe David Bowie utilize(s/d) this technique, and I'm fairly certain that Steve Albini used it on Kurt Cobain's vocals on Nirvana's In Utero. I know they're not the only ones.
 
scrubs said:
a noise gate functions on audio the way a real gate functions, like on a fence. when the gate is closed, nothing gets through. when the gate is open, everything gets through. the threshhold sets the level (volume) at which the gate opens.
Click to expand...
Exactly! ;)

Most, if not all, gates also have attack/release or threshhold adjustments so you can decide how fast or slow the 'door' opens and closes. These can be used to make the gate more transparent or add some neat chopping effects on tails, etc.
 
MOFO Pro said:
Some gates allow you to just attenuate the signal when it drops below the threshhold...
Click to expand...
And that, imho is not a function of the gate, but of an expander, which is sometimes an add-on to the gate.
 
fraserhutch said:
And that, imho is not a function of the gate, but of an expander, which is sometimes an add-on to the gate.
Click to expand...

Yup... Just wanted to point out that the feature was often available on a stand alone gate... most people associate expanders with only compressors...
 
fraserhutch said:
And that, imho is not a function of the gate, but of an expander, which is sometimes an add-on to the gate.
Click to expand...

A gate is an expander with a fixed ratio. An expander is a gate with a variable ratio. Other than that, they are the same thing. They often have variable depth, which determines the final amount of gain reduction. A fully-featured unit, like the Aphex 622, has enough control so each channel can be configured as a gate or expander.

The gate/expanders found on comps that MOFO mentioned are usually simple, lots of times with just a threshold control, and maybe a button to switch from gate to expand. The button changes the ratio from infinity:1 (gate) to something like 2 or 3:1 (expand).

If your expander or gate has enough control, try reducing the depth. A gate/expander that doesn't close fully can sound more natural on vocals or situations where there is lots of bleed, like toms.



Big Kenny said:
expanders aren't anything like compressors.......
Click to expand...

Yes they are. Expanders, gates, compressors, and limiters all do exactly the same thing. They reduce the gain of a signal when it crosses a threshold. Limiters and compressors reduce gain when a signal goes above the threshold, gates and expanders reduce gain when a signal goes below the threshold.


An aside- most people don't really expand anymore, it's mostly used as noise reduction, with the threshold set below the quietest part of the signal. This is why gates with variable release can be used with decent results in place of an expander sometimes. Their fixed ratio doesn't matter as much, as the processing doesn't affect the program material, just the noise below it.

Expanders used to be used, and still are in broadcast and wireless applications, to reverse compression. You can uncompress a signal by setting an expander to about the same settings of the compressor used to compress it. For example, wireless mic signals need to be heavily compressed. This happens in the transmitter in the mic. At the receiver, the signal is expanded, or uncompressed. The combo of compressor in the transmitter and expander in the receiver is called a compander circuit. One of the things that makes a good wireless better than a cheap one is the quality of the compander it uses.
 
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