Mastering is the last stage of an audio production which can be seen as quality control. During this process the mastering engineer will listen to the track(s) in an acoustically treated room on linear monitors. This way the mastering engineer can determine if the audio is balanced and corrects unbalanced tracks by using special mastering tools designed to be as transparent as possible.
Mastering is not an exact science. Communication between the artist / record label is necessary to achieve the optimum results both technically and artistically. It is not uncommon that a track needs several adjustments in the mix to achieve that goal.
Rick Hoekman
