I was checking out Wikipedia and noticed this:
"Error-correction codes for the audio data are corrupted, which may introduce audible errors to ripped copies." from here.

Is it true? I have some Copy Controlled CDs and although the CDs are fine I can't seem to get matching CRCs for the first few tracks (the first Track, in particular).

Yes, it is true. Especially the protection (or better: destruction) scheme Cactus Data Shield 200 uses modified error correction codes that cause artificial C2-uncorrectables.

A standalone player will perform linear interpolation on these errors ... most (but not all) ripping computer drives will simply choke upon the errors.

Although a trend towards software-only-based protection schemes can be observed. Example: The MediaMax protection seems to be popular among US CD labels. ( see http://www.mediamaxtechnology.com/HTML/index.asp )

These CDs contain a Red Book compliant audio session plus a data track with some proprietary "rights managing" software.

I bought one of those CDs lately, inserted it into my drive and successfully converted it to MP3 for my portable. I didn't let WinXP search for possible software to launch -- as always -- 'cause this autorun thingy annoys the crap out of me.

No need to install rootkit software anyway ... ^^

My drive has problems extracting audio from some of these Copy Controlled discs (note: I haven't installed the software, since I have autorun disabled). Would purchasing a good drive for ripping be an ideal solution? Or should I just rip the audio in EAC, even though the read and write CRCs are different? I hear no difference in the output but it's just odd that I have ripped so many albums with no errors and yet some of these Copy Controlled discs corrupts error-correction on the CDs - isn't this a bit too much?

1. Some drives switch on standalone-player-like error concealment (interpolation) at lower ripping speeds (4x and slower). With a copy protected disc in pristine condition, ripping these should lead to matching test & copy rips.

2. most people will tell you that most of Plextor's drives are quite tolerant towards ... erm ... non-standard CD's ... ... I find my Plexwriter Premium to be very versatile in this special branch of usage.

3. There do exist many variations of copy protections which all use different techniques and thus yield different results ... Cactus Data Shield alone has some 5 or 6 revisions ... and only 2 of them work with artificial errors IIRC.

Those are not non-standard CD's, those are CD's blatantly in violation of CD spec.

The makers should be hanged and quartered.

Well ... I was just trying not to tell anyone too much

But you are of course right

The PC drives of old that I tested perform linear interpolation, though a bit less efficiently than my CD player.



Interpolation will have no effect on CRC matching. It will just change the final result, thus the final CRC. But if the CRC are different without interpolation, they will remain different with interpolation.