I like thinking about mastering as a type of black magic. Filled with taboos and unapproachableness.
Everybody and their grandmother has an opinion about how things should be recorded and mixed, but when asked about mastering most people hush up and shrug. Mastering is a trickier subject to tackle than mixing I feel, and the delicate touch and subtleties a mastering engineer gives to a final mix sometimes sadly goes unappreciated.
However, there are certain things you mixing engineers can do to make the voodoo doctor's work easier. Mastering takes a few oddball songs that were recorded in various places by various people and makes them sound like they were actually recorded, if not in the same room, at least on the same planet. So help out the mastering process by making sure your mix is ready to be mastered.
1. Find a Mastering Engineer
Like any good product or service there is difference in price and quality. Find a dedicated mastering engineer that has some specialization instead of some guy that will happily take your money in exchange for putting a limiter on your stereo track and boosting the hell out of it.
2. Finish Your Mix
You need to be absolutely certain that you like the mix the way it is right now. A mastering session is no time and place to start worrying about if your vocals are too low or if the kick drum doesn't sound right. Make sure you are in love with the way your mix sounds so that when mastered, it will only sound better.
3. Make Sure Your Mix Isn't Overloading the Master Fader
A mastering engineer can't do anything to a mix that has already maxed out the stereo buss. If the master fader is blowing steaming red all the time, chances are there is no headroom for the mastering engineer to work with. Make sure your faders aren't overloading the master fader and try to have a nice headroom on the master fader. The amount of headroom a mastering engineer wants can vary so check with your guy how where he wants the peaks of the master to reach.
By having enough headroom on the master track you give plenty of room for the mastering engineer to work with, and he can compress and equalize and boost your mix to a mastered perfection without worrying about digital clipping. If your mix is already maxed out, select all the faders of your mix and collectively lower their volume until the master buss has a lower level to it.
4. Put Your Mix In the Right Format
Ask your mastering engineer how he likes working. Some people like breaking the mix down into separate groups, creating an added advantage to the mastering process. Does he want a typical stereo track or does he like separate instruments bounced in stems?
Making the setting up and loading up time quicker means more time and money is spent on actually working with your music.
5. Bounce to the Correct Format
CDs are 44.1 kHz, 16-bit format. That does not mean that your mix should be bounced to that format. If you recorded at 48 kHz/24 bit, it's generally a good idea to leave it to the mastering engineer to bounce the track down to CD format. The mastering engineer will want all the headroom he can get so leave the format the way you recorded it in.
And never, ever, under any circumstances bounce your tracks to MP3 for them to be mastered. It should go without saying, but MP3s cut the quality immensely so in reality, there's probably not a lot left to be mastered.
6. Take Any Mastering Plug-ins Off Your Master Fader
Before you bounce your tracks to a WAV file, make sure you don't have any crazy mastering plug-ins already on the stereo buss. Maybe you put up a nice mastering patch to impress your friends or girlfriend, but leave it off for the mastering engineer. He will not be impressed, I promise you.