There seems to be a lot of confusion among the music community about the difference between ‘mixing’ and ‘mastering’. Quite often people will tell us they need something ‘mastered’ when it becomes obvious that what they're talking about is actually mixing. So for the record:
Mixing is the act of taking a number of individual tracks like a full band including drums, bass guitars and vocals and combining them with EQ, effects and whatnot down to a final stereo (two channel, left and right) file that's ready for the CD or vinyl–almost!
Mastering is that final step in the process to get the track or album ready for commercial release. This involves a couple things, basically loudness and tone. The mastering engineer will make sure the bass, midrange and treble content is such that the track will sound good on all systems. Once that is accomplished then compression and limiting is applied to bring the track up to the full loudness level as practiced by leaders in the industry for that genre of music.
If the project includes multiple songs like an album, the mastering engineer must make sure that all the songs have a complimentary amount of bass, midrange, and treble to avoid some tracks sounding duller or bassier than others to an objectionable degree. Then overall loudness must be managed across all songs so that the tracks can be played in the proper sequence and the listener doesn't feel the need to have to touch the playback volume because some of the tracks are softer or louder than the others.
The final step in mastering is to control the amount of silence between tracks so when played from beginning to end the tracks have the proper spacing. This is called the 'pacing' of an album. In this 'era of the single' (funny how things come full-circle in this business) some people just throw an arbitrary 2-3 seconds between every cut and be done with it while others are still very specific about song spacing.
At Hilton Head Audioworks we can do mastering after the fact on your project or you can bring us music mixed at your home studio or another facility and we can master it for you; we have decades of experience with this sort of thing.
We use the Ozone Advanced mastering environment by iZotope coupled with third party plugins to achieve great results quickly, typically fifteen minutes per song unless there's some extreme issues to be dealt with.
An Example of What Mastering Can Do
Here's an example of a track that was released that was poorly (or not even) mastered. Columbia records should be ashamed…
Ok, so we know most of you aren't big band fans, but try and look past that and listen to how truly abominable this sounds. There's virtually no bass, the low midrange (the spectrum that gives instruments warmth and fullness) is barely there as well. The center midrange is way to loud giving the whole track a harsh "Wendy's Drivethrough Speaker" treatment and the highs, well who knows with all the other things that are out of whack here. So let's see what we can do for this track in mastering.
Well, we think this sounds a lot better, especially if you compare from about 5:40 to the end where the full band is playing. There are certain things that we'd still like to change but simply aren't addressable when all the tracks are mixed together specifically: the cymbals sound kind of splashy/trashy but if you try and zero in on that it takes away the nice zing of the upper end of the trumpets and saxes. One of the key things in mastering is to make sure you don't throw out the baby with the bathwater so if we run into some of these kind of situations occasionally we might suggest a remix if it's possible and deadlines permit.