MI7®

When trying to improve your final mix in a mastering process you should apply a low-cut to your mix, before starting to use compression. This is also relevant in mix situations.

The reason is that deep frequencies between 20-40 Hz hardly can be hard to hear on common nearfield monitors. They also seem to contain "less" energy in your mix, than they actually do. These frequencies are normally part of Bass-drum, Bass or effect-sounds, and will - if allowed - influence a lot on compressor-behavior on the total mix and hence create pumping effects.

Another reason to lowcut is to secure better playback on smaller speakers. If you try to playback a 40 Hz tone on a small clock-radio, it will distort the signal at a far lower level than for instance a 1 kHz tone. Therefore a roll-off on sources containing really deep frequencies is essential to secure good musical replication.