Compression

Compression will take the louder parts of a signal and make them quieter in a controlled way.

You have 5 controls at your disposal in most compressors as follows:

Threshold: The most important control. Will set the volume threshold that the compressor will start to consider "loud". Anything louder than this threshold will be turned down by the compressor.

Ratio: The second most important control. Will set how much a signal over the threshold gets turned down. Is expressed in ratios of X:1 (eg. 2:1, 4:1, 10:1, etc...) The larger the leading number, the more the signal gets compressed when "loud".

Attack: Sets how quickly the compressor turns down the "loud" portions. Is usually expressed in milleseconds (1000th of a second) and is usually in the range of 1-20ish.

Release: Sets how quickly the compressor brings the signal back up after it is no longer "loud". Usually expressed as either milleseconds, or seconds, commonly at 100ms.

Makeup Gain: Since compressors will make the loud parts quiet, the average signal level after compression will always be quieter than before compression. The makeup gain lets you turn up the compressed signal to match the pre-compressed level.

The Compressor Is Like Your Mother

THRESHOLD: The level she asks you to turn the music down.

RATIO: How much you turn down the volume after she shouts at you.

ATTACK: How fast you react.

RELEASE: How fast you turn the volume back up as soon as she closes the door.