More On Multi-Session Audio CDs

Our TTOTD from 10/6/97 involved playing multi-session CDs in standard audio CD players. “We’ll assume that you are working with a “stand-alone” audio CD recorder (like the ones from Marantz, HHB, and others) and not a computer-based CD burner. Given that assumption, there generally is a command or front panel switch to make the recorder “fix up” the disc, or write a table of contents to it. This turns the multi-session CD into a Red Book CD, which should read fine in most regular audio CD players. You will not be able to write any more data to the multi-session disc after doing this, so be sure you have what you want on it!In most cases, it is not possible to play a multi-session CD in an audio CD player without performing this step.” Reader Wim V. in Belgium offers the following clarification of the term “multi-session”: “Fixing up a disc does not turn a multi-session CD into a Red Book CD. The standalone burners are able to write one track at a time and add tracks in a later recording “session”. But writing one track is not creating a session in the technical sense of the word. The CD-R keeps a table of contents in a special area on the disc, that is not readable for regular CD players. Fixing up copies this special table of contents into a regular table of contents, readable by regular CD players. Fixing up also closes the CD by writing a lead-in (which contains the TOC) and a lead-out area on the disc. The whole contents of the disc, lead-in, tracks and lead-out make up a session in the technical sense. These discs are single-session. Computer burners are able to write several sessions, each consisting of a lead-in, tracks, lead-out, hence multi-session discs. A CD-player can read the first session on such discs, not the other sessions.” Thanks for clarifying Wim, you are correct. Where we got into trouble was referring to the discs created in stand-alone CD recorders as “multi-session”, which technically they are not…

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