#2
I believe it's good for if you're playing with really high gain and distortion at high volumes because it helps get rid of any unwanted noise coming from your guitar.

I haven't touched an electric guitar in quite some time though, so I could either be wrong or someone else may be able to provide a better explanation.
Banging on a trash can
Drumming on a street light
#3
noise gates distinguish between the guitar signal and the unwanted background noise/hiss and cuts these frequencies out.

the threshold at which these freqs are cut out can be set on the pedal.

quite useful in a studio setting but unless you're getting a lot of hiss and noise off your set-up they can be a bit surplus to requirements sometimes
#5
Quote by controlfreak
the threshold at which these freqs are cut out can be set on the pedal.
i've never actually seen a noise gate in pedal form, who makes em?

and yeah, a noise gate is a signal processor desgined to attenuate signals below a threshold whose value you set yourself. so if you set the threshold at xdB, then any signal above xdB will cause the gate to open, allowing signal through, and once the signal falls below the threshold, the gate closes and you have silence.
there are other controls on the unit, but thats the basic operating principle. they're used for eliminating unwanted noises, like drum spill, mains hum, etc etc
#6
Quote by Alucard II
i've never actually seen a noise gate in pedal form, who makes em?


the nicest nose gate ever is a pedel - ISP decimator

Boss also makes one...the NS-2