How much Compression is too much?

While compression can work wonders to add punch and presence to your mix, it can also ruin it faster than you can say "it's destroyed". Below are some guidelines to help you avoid destroying your mixes with too much compression...
Compression typically performs best when gain reduction occurs only where peaks in audio signal are present, even if those peaks occur several times throughout a mix. The idea is to control the peaks in signal all the while having most of the signal remain underneath the threshold and hence, uncompressed. Optimum gain reduction occurs once you have achieved this type of balance.
If the compressor is always attenuating (gain reducing) the signal you feed it, you are not achieving optimum gain reduction. This is where compressors start to ruin mixes with what is called pumping and/or breathing.
Pumping and breathing occur when so much of the signal is crossing the threshold that the overall volume of the signal is reduced entirely! Once the dynamics and/or peaks in the original signal soften & go back underneath the threshold, the volume actually becomes louder again due to the original signal recovering from excessive compression!
Compression is a powerful tool: Abuse it, and compression will ruin your mix. Treat it with respect, and compression will enchance your mix!