We recommend getting your mixes to sound the way you want before mastering (
with some important exceptions mentioned below ). Mix as if you are not going to
master. Multi-band compression and limiting, which are often used during the
mastering process, have the aural effect of bringing up lower level mix elements.
Sometimes engineers will try to “pre-compensate” for this effect by keeping some
mix elements intentionally lower. We recommend against “pre-compensation”. We
have found that well balanced mixes translate better through the mastering process.

Exception 1: Don’t Perform Fades
Let your mastering house fade your mixes to your specifications. Mastering gear
performs a much higher resolution fade than the typical DAW. This is one area
where a DAW does not shine.

Exception 2: Don’t Apply Master Effects or Processing to a Mix
This means, don’t apply a limiter, EQ, compressor, processor or effect to a “master
fader” ( in ProTools® ) before you bounce to disk. Or don’t run your finished mix
through an eq, “Finalizer®”, compressor or limiter before sending it off to be
mastered.

Exception 3: Aim for -3 dB as your hottest level
Don’t slam the meters on your tracks or mixes to hit zero. ( and obviously don’t slam
levels over zero! ) With 24 bit recording resolution, it is much worse to go over zero
than not hit the top of scale. We recommend you imagine hitting the top of the
meters when they are 3 dB down from 0 dBFS.