What does it mean to "master" a multitrack project? Wouldn't you be mixing it? If so, wouldn't you try to make it sound as good as you possibly can while mixing? At what stage in mixing would you refrain from improving the sound to the best of your ability, instead choosing to make this improvement in a later "mastering" process?
I've spent most of my life in professional recording studios, and I used to think I understood what "mastering" means. Originally it was necessary to control levels and keep the stylus from jumping out of the grooves on the record player. It was a final step before manufacturing, ensuring that the tracks on a lp, tape, or CD were in the right sequence, were of the right duration to fit on the side of an lp or cassette, and had an output and tonal curve that conformed to manufacturing and broadcast standards. When different tracks (for an album) came from different producers and studios, an attempt was made to make the tonal palette of the different tracks more consistent with one another.
In almost all cases mastering took place in specially designed rooms, using extremely expensive amplifiers and monitors, and highly specialized mastering engineers who generally weren't known for mixing multitrack. As I played, arranged, wrote, produced, I never gave it a moment's thought.
So I'm a dinosaur, somebody bring me up to date. I see this word everywhere now; 22 year old guys with seventies hair in music stores talk about it. What does mastering mean today, to a composer/producer, project studio owner, and Logic user such as myself? How do I improve the sound of my music through mastering? (As it is, I judiciously use an assortment of compressors, limiters, and eq's, as well as assorted monitors and headphones, whenever I mix.)