Knee: Soft means the compression will be applied gradually as the signal approaches thethreshold. Hard means the compression will be applied quickly as soon as the audio surpasses thethreshold.!Input / Output or Gain: The compressor is effectively turning down the louder parts of the audioand leaving the quieter parts untouched, thus reducing the difference between the louder andquieter signals. So this will turn down the overall volume of that channel. So you’ll most likely wantto use the output or makeup gain to bring the level back up so it works well in the mix. I like tobypass the plugin on and off to make sure the channel is still well balanced in the mix.Fast attack and release times can sometimes cause low frequencies to distort. Low frequencieshave long waves so the fast attack causes the gain reduction to begin working within one cycle ofthe wave causing it to clip. The problem is, sometimes you need the fast attack time to attenuatethe transient of the audio. My preferred fix for this is to increase the ‘lookahead’ time. This meansthe compressor begins the gain reduction a few milliseconds before the transient, allowing thelow frequencies to pass through undistorted.Type Of Sound Ratio Attack ReleaseUpfront Vocal 3:1 to 4:1 Below 0.1 ms 40 to 80 msAgressive Bass 3:1 to 4:1 16 to 20 ms 50 to 300 msTight Drums 2:1 to 4:1 1.5 to 6 ms 50 to 250 msPiano Weight 3:1 to 8:1 20 to 75 ms 0 to 30 msControlled Guitar 3:1 to 4:1 10 to 20 ms 40 to 100 msThicker Sound 2:1 to 4:1 3 to 12 ms 20 to 75 msParallel Compression 8:1 to ∞:1 0.5 to 1.5 ms 50 to 150 ms