Gaps & CUE Sheets

What? In this text a 'gap' means the pause between 2 tracks. 'Pause' is a misleading word, as a gap often contains music, e.g. a fading out of the previous track, an intro for the next, or a mix of both. Many gaps seem to be pure silence, but often a closer look reveals they contain a silent noise. Next picture represents a typical CD with a couple of tracks (T) and their preceding gaps (G). Structure

A gap's start position is called index 00, while index 01 is where a gap ends (and the next track begins). Many gaps are 2 seconds long, but any length is possible, even minutes! Occasionally a gap is a track on its own (a so-called hidden track, often G1).

Use by CD players. Gaps are 'connections' between the tracks and are only played by your CD player device in case of normal playback (normal track order). They are skipped if the order is different from the normal order, or if you pick a specific track T (then only T will be played and not its preceding G).

Link with EAC. When EAC rips a CD and splits it into separate audio files, what happens with the gaps? By default EAC and most other rippers append (include) each G to the previous T (which is what most people want). If you want something else (append G to next T or leave out G), you must select it before each rip.

Further Details: The above options are only relevant for separate tracks. A CD image contains all gaps anyhow. If you do not do a gap detection, EAC sees no indexes 00 (only 01), so it does not distinguish T1 from G2, and will rip T1+G2 into one WAV. Yes, that's Option 1. Options 2 & 3 can be chosen from the action menu and only after a gap detection (Action | Detect Gaps or F4), which makes the indexes 00 visible (that's where you want to have the rip split into tracks). In Option 1, G1 is lost (as there is no T0), but that is not so important. CD players don't play G1 (it can only be played via rewind). What's more, G1's first 2 seconds are never ripped/played. They are no real music, rather a leadin required by the audio CD standard (Redbook). So, ripping G1 means that you rip the part of G1 after the first 2 seconds (which is usually only a few milliseconds or nothing at all). Very occasionally G1 is longer and contains a hidden track. If you want to rip G1, there are several things you can do. I already mentioned you can create an image. You can also select the first track and do Action | Copy Range. This will rip G1+T1 into one WAV. If you want to rip G1 and T1 as separate WAVs, do Action | Copy selected tracks Index-Based.

CUE Sheets

What? Suppose I have an audio file, how can I tell what part of it belongs to G and what belongs to T? I'd need to know where G starts (index 00) and ends (index 01) and the rest of the file is then T. Exactly that info is stored in a CUE sheet!
A CUE sheet is easy to read in Notepad. Let's read the CUE sheet on the right together. It says: "The file 01 - Wild World contains T1, in which 00:00:00 to 00:00:33 is a gap".
This CUE sheet also suggests that the ripper has chosen to append to next track - do you agree? As you see the CUE sheet also mentions the CD artist's name, title, tracknames (and sometimes ISRC codes, which is similar to a book's ISBN code).
CUE sheets displays the time in MSF (minutes:seconds:frames), for example 00:00:33 (1 frame is 1/75 seconds). EAC displays the time in either frames (00:00:33) or hundredths of seconds (00:00:44). You can change that in the EAC Options.

Making. You already know there are 4 ways to treat the gaps in EAC. Well, each such ripping way has its own type CUE sheet:

Use. CUE sheets are mainly used to burn a CD identical to the original (with the typical 'gap behaviour'). Without a CUE sheet the CD player will not distinguish gap audio from track audio, but maybe you don't mind that, as it is not essential. Just note that if no CUE sheet is used, a program like Nero will spontaneously insert 2 seconds' pauses between all your audio files - which you don't want, as the gaps are already present in your ripped audio - so you must set these pauses to 0 seconds every time.
In order to burn, just load the CUE sheet in the burning program, and burn the CD! All the info from the CUE sheet (indexes, CD info...) will be used by your burner to create a CD that will show that typical gap behaviour when played in a CD player (as I explained earlier).
Some audio players can play CUE sheets: they take advantage of the indexes to play the audio, like a real CD player. That is particularly useful for CD images.