Compression; how does it work?

Question

I know it's good for stuff like second-hand tapping, hammering, pulling off, etc. because it makes the loud and soft sounds sound the same, but then what exactly does the attack do? Does it just make the initial sound wave louder when you turn it up? And sustain is how long the signal lasts? So if I wanted more crunch, I'd turn the sustain down and the attack up, right?

Answer 1

Think of a wave with the top cut off - that's what compression does. The attack adjusts the amount of signal to cut - turn it up and hit a hard note or chord - it cuts it off. Turn it down and it only cuts the very loudest peak. Sustain increases the level as it is decaying - it's like starting a note with volumn down and then turning it up as it is ringing. Good for single note solos. So . . to get "Crunch" you usually don't use compression at all - it's a distorted first attack of the chord that then levels out to a clean sustain - and that's what the guitar and amp do naturally - if the gain is set right.

Answer 2

Actually, Compression boosts the soft sounds, decreases the loud (Peak) sounds, sort of evens everything out and then holds onto it for as long as it can. Compression does to sound what you would do to a night crawler if you were trying to hold onto it for as long as you could! Hope this helps

Answer 3

http://en.wikipedia.org/wiki/Audio_level_compression