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What Is A Red Book CD?

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Red Book refers to a set of professional specifications for audio CD's. The reason it’s called that is very, very simple - I promise! Ready?

  • They are so named because the colour of the cover of the book that contains all these technical specifications for the standard audio CD is red.

There! I told you it was simple!

And if you expect your work to be professionally replicated, your production master CD must conform to the tech specs outlined in this book.

Every CD I master adheres to this professional standard.


CD players are made to read these industry standard discs. Therefore, your CD will play in any CD player. You wanna be heard, right?!

What Are The Main Features of a Red Book CD?

All audio CD's have three defined areas:

  1. The Lead-In Area which contains the Table Of Contents (TOC) which occupies first area on a CD - the innermost 0.4 millimetres of the disc. It contains a list of all the Track ID positions (start times) of all the audio tracks on the disc.
  2. The Program Area contains all the actual audio. Some basic specifications include:

    • Maximum playing time is 79:57 - this was originally 74 minutes.
    • Minimum duration for a track is 4 seconds (including a 2-second pause).
    • Maximum number of tracks is 99.
    • Maximum number of index points (subdivisions of a track) is 98. (This is rarely used nowadays).
    • International Standard Recording Code (ISRC) should be included.

  3. The Lead-Out Area simply marks the end of the Program Area.

All discs are written in Disc-At-Once (DAO) mode.

Warning! Not all software is created equal! Only specialized CD mastering software will create such a CD master.

If the disc you get from a studio is not accompanied by a “PQ Sheet” you probably do not have a industry standard disc.

Needless to say, all the people I work with who want physical CD masters, will always get the accompanying PQ Sheet.

What's a PQ Sheet?

An audio CD contains sub-code data which are designated by the letters P to W.

Back to the Lead-In Area: the Q sub-code data contains the TOC complete with Track ID positions. This is why when you load a CD into your player you instantly get information about the number of tracks, their lengths, and the total length of the CD

On again to the Program Area: the P sub-code data show where music tracks start and end.

The Q sub-code data contains time information. It also contains four other types of data:

  • Pre-emphasis - rarely used now; an early form of digital noise reduction.
  • ISRC codes (Already discussed here).
  • Media Catalogue Number - a 13 digit bar code for CD's which you apply for and is provided to you by the EAN and UPC authorities.
  • Copy Prohibit On/Off - this determines whether or not digital copying is allowed by digital recorders (DAT machines, Mini-Disc recorders, etc.) via their Serial Copy Management System (SCMS) circuits.


A PQ sheet is simply a printout charting all this information, timing and otherwise, for the accompanying CD.

What about the rest of sub-code data – R to W?

They're mostly unused at present.

Stand alone CD recorders do not create a red book CD.

Most consumer programs do not, either. Here is a partial list, however, of CD mastering software programs that do:

  • Wavelab (of course!)
  • Studio One Pro
  • Toast
  • SoundForge
  • Sequoia

What Else Should You Know?

While the maximum length of CD can be almost 80 minutes, most replicators only guarantee lengths up to 74 minutes.

Remember that one of the original spec for the CD was a maximum length of 74 minutes.

There can still be some older players out there that may have trouble with longer discs.
This shouldn't be a problem as most albums are between 40 to 60 minutes anyway.

You know what's said about too much of a good thing.

Having said that, I’ll say this once more: every audio CD mastered at Mister’s Mastering House conforms to the red book standard!


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