文档介绍：pression Page1
Part 1: Paul White looks at different gain-control elements and their
effect on audio.
Compression is a subject that has been covered on numerous occasions in
past issues of Sound On Sound, but it is worth revisiting, both because of the
importance pression in contemporary music production and because
many people are unsure as to the best way to use pressors.
However, in order to avoid retreading old ground, I'll only be giving a very quick
overview of the principles pression before moving on to some of the
more advanced concepts — if you'd like a more in-depth discussion of basic
compression, then refer back to my article pression in SOS April 1997.
In A Nutshell
Most of you probably know that pressor is a device for automatically controlling the level
of an audio signal. More specifically, pressor 'turns down' the audio when the level
exceeds a threshold set by the user. The amount by which the gain is turned down depends
on the ratio of pressor — for example, if a ratio of 5:1 is set, an input signal
exceeding the threshold by 5dB will be output with a level of only 1dB over the threshold.
Once the signal falls back below the threshold level, the gain returns to normal. It's exactly the
same as manually turning the level down with a fader whenever it gets too loud, but it's much
faster to respond than any human and it's to