Compressors - also known as dynamic processors or gain reduction (GR), are used to tame transients, peaks, and to narrow the difference between the loud and the soft.

When used properly, compressors are one of the most useful tools in the audio processing chain.

Knowing what they do, as well as how they do what they do is absolutely crucial ...before you simply start inserting them on every track, you need to know what your end result will be. Nothing wipes the life, depth and dynamics out of a song faster than a misused gain reduction device.

There is no "one setting fits all recording scenarios" function. You have to take each track into consideration, and often within the context of the other tracks, and determine how much and to what degree of compression you should use.

Here are the basic parameters to a compressor:

Ratio: This determines how much you want to compress the signal.

Threshold: This determines where in the db scale that that the compressor starts to work. For example: If you have a threshold setting of -10db, this means that the compressor won't start working until the signal reaches -10db, so anything below that level will remain unaffected.

Attack: How fast the compressor starts to work.

Release: The duration of how long the compressor continues to attenuate gain.

Knee: a function that determines the difference in the transition between the processed and unprocessed audio.

Makeup Gain: This function allows you to determine the level of the signal on the output of the compressor

These are very basic explanations as to what a gain reduction device does.

I suggest you give this a read to familiarize yourself with Gain Reduction and to learn more about the functions and various uses in depth:

[[url=http://[/URL]="http://en.wikipedia…"]Dynamic range compression - Wikipedia, the free encyclopedia[/]="http://en.wikipedia…"]Dynamic range compression - Wikipedia, the free encyclopedia[/]