Au - Compression

Definition

Compression is an audio signal processing operation that reduces the volume of loud sounds or amplifies quiet sounds thus reducing or compressing an audio signal's dynamic range

Threshold - maximum amplitude (loudness)

Output Gain - added after the compression to get your audio levels back to the correct amplitude

Ratio - how much the compression algorithm is applied

          - as a guide: 2x1 for low compression, 5x1 for medium, and 8 or 9 for strong compression

Attack - how quickly the compression will kick in when it encounters amplitude over the stated threshold

Release - how quickly it lets the compression release