ok so ive been trying to determine the offset of my CD-rom drive, and ive been comming across all kinds of different readings.

first i made a test CD in EAC and used that to detect the offset on my plextor px-708a EAC was reporting an offset of 2257 in the compression options window. i also found another offset setting in the drive options window, that was detected as -3.

then i went to the accuraterip database and that reports an offset of +30

then i downloaded plextools and on the general drive info tab it lists both the audio read offset and audio write offset as -120 bytes.


is -120 bytes the same as a -120 setting in EAC?

i dont get it, which one is right? am i sweating over offsets too much, does it really matter at all? i just want to make sure im getting a 100% accurate rip, and from what i read it seems that if you dont correct your offsets properly you may be missing some information from each track.

perhaps someone could explain to me what offsets are in lamens terms.

anyone, anyone? beuler?

One stereo sample is 4 bytes, so -120 in Plextor is the same as -30 in EAC.

Creating an offset detection CD and using it returns the combined read+write offsets, not just the read offset of the reader.

Basically, the offset is the position of the track marker in the audio. A bit late, or a bit early... It is not important for the accuracy of the audio data. Unless you burn with EAC with a Teac burner capable of overwriting into lead-in/out, offset correction won't help you with accurate copies. If your drives don't overread, You loose more info once the offsets are corrected than without correction.
Setting the exact offset correction helps with copies of copies, with copies of custom made CDRs (from MP3, or analog recordings), with comparing CRCs using different drives, and with using AccurateRip (that compares CRC between different users).

what if im ripping a cd which have tracks that flow into one another with no audible gaps, a live CD for example... would the track-changes be in the wrong place? usually i set my mp3 player to random so would i possibly hear the last bit of the previous song or perhaps the song would start just a bit too late?

If the song begins abruptly, with a percussive sound for example, yes, it is possible that you hear the offset. However, commercial CDs are themselves offsetted. Using correction won't necessarily move the track change in the right place.

The offset correction used in rippers like EAC, or Plextools, ensures that everyone uses the same reference. But CD manufacturers themselves can use a different reference. In fact they probably just copy the offset of the master sent by the studio, just checking that nothing wrong is audible, but not taking the time to readjust everything sample wise.

So if what you seek is an accurate mastering, you have to do it yourself with a wav editor. You might want to take into account, in the process, that the CD that you are making might be read without offset correction, so a little margin is welcome (putting the track markers a bit early, so as not to cut the begining of any song). Commercial CDs should be mastered this way.

ok that helps alot.

one more question, as i said there are 2 different places where you can input your drives offset into EAC... one under the Drive options, and one under the compression options. should both of these be set to -30 or do i only need to worry about the compression options.

Only in the drive options. Compression offset is a comlpletely different thing.

you have been very helpfull, thank you.