mastering is one of the steps i learned about during the recording of this album. it's not a very tangible, easy to understand process, until you've actually attended a session.
mastering is the stage in which the final equalization and volume level of each song is set and evened out. during it, volume and EQ within the song, and along the whole album is smoothed out and made uniform - giving it more cohesiveness as an album. the final song order and spacing between each song is decided during this final stage before duplication.
clarity. punch. tone. depth. warmth. character. these are some of the things given to the songs during mastering. and they're done even better at the ears of someone who has never heard the songs before. read here or here for more about mastering.
the cost of mastering varies a lot, depending on how picky you are. it can range from $30 to $120 a song, or higher. being present (and choosy) during the mastering session makes the price per hour instead of per song. because i'm picky and cheep, i went with the low end, so i could be there for mastering. here's how it added up:
10 songs took about 7.75 hours X $30/hour + $30 for CD master + tax, etc = $266 for mastering.
(so far, we're at about $746 total for the album)