by the4thImpulse » 21 Nov 2013 20:12
3-12 dB, there is no rule or right or wrong level, 3-12 is the range in which most people will tell you to leave it at (i personally stay in between 3 and 6). The reason for this is mastering, if your mix is already floored to 0 you can't increase any frequencies with an EQ or through multi and compression. keeping it low gives the mastering engineer more options and freedom.
Moving the master down does essentially do the same trick, it is not preferred due to the old methods of mixing. When I go to mix my track I move all the faders to 0 and slowly move each up. Starting with kick/snare and bass, moving to vocals and lead lines and ending with the rest of the drums and whatever else I have. Aiming the mix to be in the range of 3-12 dB of headroom.
Now something that I've been told but have not personally experienced is digital clipping, if you turn the master up so the signal is above 0db you get those obvious clipping sounds. What some have told me is clipping on the individual faders can harm the sound in the same way clipping on the master harms the sound, even when the master itself isn't clipping. Is always a good rule to never let a single track clip, if you have to turn down the master fader to prevent the master from clipping than do it.
As a side note, in the analog realm turning down the master because the mix is too hot will decrease your signal to noise ratio. In digital the signal/noise ratio is never a problem unless you recorded analog sounds (microphones) with poor gain settings. Turning down the master only to turn it up in mastering is like turning the noise floor louder, mix it better, record it better.