You may find yourself, a young mixing engineer, frequently asking yourself the question "Why aren't my mixes as full and loud as commercial mixes?" The answer, my friend, is mastering.
Mastering is a black art to some. Very little information regarding the process was available to the public at large until recently. Simply put, mastering is a form of post production and the final step between the mixing board and the manufacturing plant. Getting your mixes ready for show time with a variety of signal processing that can include additional eq, compression, and limiting. The biggest difference between the mixing and mastering stages of a recording is that the processing for mastering is applied to the entire mix as opposed to the individual tracks.
A common misconception is that mastering a recording is all about volume. While it's true that during the mastering process the overall volume is brought up, that is only a very small part of the overall task. The main goal of mastering is to make sure all frequencies are well represented in the spectrum and that the recording sounds as good as it can on a wide range of playback systems from multi-thousand dollar hi-fi systems to tiny cell phone speakers.
Nearly 100% of all recordings benefit from at least some part of mastering. Whether it's making hip-hop and rock tracks in your face, or making sure every nuance of a symphony orchestra is heard. It's the mastering engineer who has the experience, equipment, and the ears to make this happen.
Other mastering processes include putting the tracks into their final playlist order as well as things like fade ins, fade outs, cd text, and hidden tracks. Finally assembling everything into a distribution medium i.e. CD, DVD, and MP3.
Hopefully this helps put a few things into perspective before you have your project mastered. If you would like to know more, here is some great recommended reading on the subject...
- Wikipedia entry on Audio Mastering
- Mastering Audio, Second Edition: The Art and the Science by Bob Katz