A basic explanation of mastering is the fine tuning of your mixed tracks to prepare them for duplication/replication, radio, and online play. The process of mastering brings unity to your album/CD. Mastering involves skillfully optimizing levels, Equalizing and applying compression to your tracks so they play uniformly on iTunes, MP3 players, Radio, car stereos, youtube, etc..
The mastering process also corrects minor mix deficiencies, provides noise reduction, enhances flow by creating the proper space between tracks, adds ISRC codes, adds CD-Text information (Artist, Title, and Track Names that can be displayed by some CD players), Adds MP3 tags, album art and track information. And the one thing mastering does that is always asked is pump up the volume of your tracks.
Mastering also provides a fresh pair of trained ears to listen to your work and take a good sounding album to a great sounding album.
File Types, Sample Rates and Bit Rate
Uncompressed digital audio files (WAV, AIFF, etc.) with high sample and bit rates that are native to the mixing session are best for mastering. There is no need to down sample or up sample the final mix in preparation for mastering. We can work with almost any file types, bit and sampling rates. Try to avoid compressed audio file formats if possible (MP3, AAC), mastering is limited with compressed file formats.
To prepare a mix for mastering there is no need to use heavy brick wall limiting or compression on the final mix track. A dynamic mix is always easier to master than a squashed one with no more room for adjustments. It is important that the master channel not clip to retain all of the dynamics and transients that relate to impact and punch of the mix. It is best to leave about 12dBs of headroom on the final mix for mastering. This gives the mastering engineer plenty of room to work their magic.
Fade-ins and fade-outs should be done during the mastering process. This allows all of the compression and equalization adjustments to be uniform through the entire mix, prior to the fade-in or fade-out. If you have a specific requirement for fades, please include that information and any special instructions in the notes.
Album Title, Artist Information, Track Names and Track Order
During the mastering process and final master delivery all track titles, track order, artist information and album title will be embedded in the final master CD-R and DDP Image as CD Texts. This information is stored on the CD’s table of contents and is displayed with compatible CD players. This information is different from track titles that are shown when the disc is loaded into iTunes and computer MP3 players. iTunes and computer MP3 players pull data from online databases such as Gracenote.
Along with the CD Text, ISRC (International Standard Recording Code) information also can be embedded into the final master CD-R and DDP Image. The ISRC is the international identification system for sound recordings and music video recordings. Each ISRC is a unique and permanent identifier for a specific recording, independent of the format on which it appears (CD, audio file, etc) or the rights holders involved. ISRCs are widely used in digital commerce by download sites and collecting societies. An ISRC can also be permanently encoded into a product as its digital fingerprint. Encoded ISRC provide the means to automatically identify recordings for royalty payments.