Taken from the rec.audio.pro FAQ:
Q6.3 - What is mastering?
Mastering is a multifaceted term that is often misunderstood. Back in the days of vinyl records, mastering involved the actual cutting of the master that would be used for pressing. This often involved a variety of sonic adjustments so that the mixed tape would ultimately be properly rendered on vinyl.
The age of the CD has changed the meaning of the term quite a bit. There are now two elements often called mastering. The first is the eminently straightforward process of preparing a master for pressing. As most mixdowns now occur on DAT, this often involves the relatively simple tasks of generating the PQ subcode necessary for CD replication. PQ subcode is the data stream that contains information such as the number of tracks on a disc, the location of the start points of each track, the clock display information, and the like. This information is created during mastering and prepared as a PQ data burst which the pressing plant uses to make the glass pressing master.
Mastering's more common meaning, however, is the art of making a recording sound "commercial." It is the last chance one has to get the recording sounding the way it ought to. Tasks often done in mastering include:
- Adjustment of time between pieces
- Quality of fade-in/out
- Relation of levels between tracks (such that the listener doesn't have to go swinging the volume control all over the place)
- Program EQ to achieve a desired consistency
- Compression to make one's disc sound LOUDER than others on the market
- The list goes on.
A good mastering engineer can often take a poorly-produced
recording and make it suitable for the market. A bad one can make a good recording sound terrible. Some recordings are so well produced, mixed, and edited that all they need is to be given PQ subcode and sent right out. Other recordings are made by people on ego trips, who think they know everything about recording, and who make recordings that are, technically speaking, wretched trash.
Good mastering professionals are acquainted with many styles of music, and know what it is that their clients hope to achieve. They then use their tools either lightly or severely to accomplish all the multiple steps involved in preparing a disc for pressing.
Hope this helps...
Bruce Valeriani
Blue Bear Sound
