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Re: Interesting EAC results

Posted by andy_c on March 1, 2007 at 15:12:47

In Reply to: Interesting EAC results posted by Presto on March 1, 2007 at 13:19:08:

Hi Presto,

Why not use "Test and copy selected tracks"? That way, the CRC of a test read is compared with the CRC of the actual read. This avoids having to do manual bit-for-bit compare of two consecutively-ripped files.

Also, are you doing read offset correction? If not, and you compare rips done with two different drives, offset of one file relative to the other will need to be done before comparison.

I've done a number of different experiments with about four or five drives with secure mode and burst mode (but not fast mode). Results of burst mode vary considerably from one drive to another. One drive, the AOpen COM5232AAH Pro, passed level 5 (the highest) of the CD-check audio test disc at cdrinfo.com. Using burst mode with this drive, the only time I ever got mismatched CRCs with "test and copy" was on discs that caused the rip to slow waaaaay down in secure mode. Rip speeds were up around 24x average and higher. From these results, one might conclude that burst mode is almost always safe. However, I also tried another drive in burst mode with very different results. This was a LiteOn model. Using burst mode with this drive, I got at least one mismatched CRC on every disc I ripped.

My current strategy is to use two drives. First, find a drive that rips very fast in secure mode and use it for almost all rips. Second, find a drive that has the best error correction performance possible. If the disc cannot be ripped with the drive that's fast in secure mode, use the drive that has the good error correction. I've never found a drive that meets both these criteria. The ones that rip fast in secure mode are the ones that don't cache audio data when ripping. For an example of a currently-available drive that's very fast in secure mode, see this page. Scroll down for EAC secure mode benchmarks. I use an LG GSA-4167B for most of my rips. It will usually do an average rip speed of 24x across the disc, but its error correction is not so good. I use a Plextor to rip the ones that the LG won't do. I don't think this LG drive is available anymore. The ASUS drive I linked to above is the only secure mode speed demon I know of that's currently in production.

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