Compact Disc manufacturing

Compact disc manufacturing is the process by which commercial compact discs (CDs) are replicated in mass quantities using a master version created from a source recording. This may be either in audio form (CD-Audio) or data form (CD-ROM). This process is used in the mastering of read-only compact discs; CD-Rs, CD-RWs, and DVDs are made somewhat differently, though the methods are broadly similar.

A CD can be used to store audio, video, and data in various standardized formats defined in the Rainbow Books. CDs are usually manufactured in a class 100 (ISO 5) or better clean room; they can usually be manufactured to quite strict manufacturing tolerances for only a few US cents per disk.

CD mastering differs from burning, as the pits and lands of a mastered CD are moulded into a CD blank, rather than being 'burn marks' in a dye layer (in CD-Rs) or areas with changed physical characteristics (in CD-RWs). In addition, CD burners write data sequentially, while a CD pressing plant 'writes' the entire disk in one physical stamping operation.

All CDs are pressed from a digital data source, with the most common sources being low error-rate CD-Rs or files from an attached computer hard drive containing the finished data (e. g., music or computer data). Some CD pressing systems can use digital master tapes, either in Digital Audio Tape, Exabyte or Umatic formats. However such sources are suitable only for production of audio CDs due to error detection and correction issues. If the source is not a CD, the table of contents for the CD to be pressed must also be prepared and stored on the tape or hard drive. In all cases except CD-R sources, the tape must be uploaded to a media mastering system to create the TOC (Table Of Contents) for the CD. Creative processing of the mixed audio recordings often occurs in conventional premastering sessions. The nickname often used for this is "mastering," but the official name, as explained in Bob Katz book, Mastering Audio, edition 1, page 18, is premastering. After all, there still has to be the creation of another disc which has the premastered audio but which supplies the surface on which the metal master will be electroformed. So, there still needs to be the grandmother disc before the master stamper can be formed atop.

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