Alex: Could someone explain what makes a CD drive better or worse than another (other than speed). I was under the impression that it was simply a digital pickup. Do some drives misread bits more often? If so I thought CD audio had a large amount of error correction built in.

Good question, Alex. We should probably put this in the FAQ. Yes, some drives mis-read more often than others, but when we're talking about Digital Audio Extraction, we're not so much worried about the bits as we are worried about the blocks. Read on...

Trevor: From what I gather from reading the material on the net, CD Audio does indeed have error correction built into it. However, most cd ripping programs just read the digital information from the audio disk without attempting to use any form of error correction.

Not strictly true, Trevor. CD Audio does use error correction (but on a much smaller scale than ROM data CDs do). It's just that the error correction information can't be sent back to the computer with most CD-ROM drives. Most CD-ROM drives aren't built with Digital Audio Extraction in mind, so the circuitry and drivers to perform block-accurate addressing on audio tracks simply isn't there. There are some notable exceptions (Plextor), but for the most part, it's up to the ripping software to perform after-the fact error correction by overlapping the reads and sliding the samples together. A discussion of this can be found at the CD-Recordable FAQ.

Which is why every decent ripper out there has error correction of some kind or another built-in. It's just that some do it more agressively than others. Some default to an agressive error correction scheme, others default to a faster method with less error correction, and require you to tweak the settings to error-correct more agressively. In my personal experience, I've found that different pieces of software will/won't work on different drives, regardless of whether or not they claim to do great error correction.

For instance, on my work computer, the only software that can work at all is WinDac32. Exactaudiocopy and Audiograbber/Audiocatalyst choke completely on it. On my home computer, EAC and WinDac die, but AG does fine.

Something I've noticed is that many CD-recorder drives support digital audio extraction quite well, especially if you use their bundled software to perform the extraction. For instance, I can rip quite well on my new DVD+CD-RW drive using the functions in Easy CD creator 4.

___________
Tony Fabris