The Finch Formerly Known As Gold

26 June 2005

We got your pregroove wobble right here

Previously in this space on the Teac GF-350:

One word of warning: the GF-350 expects CD-Rs (or CD-RWs, if you can find any) that are specifically labeled for digital audio. I was unable to trick it into using the cheapie CD-Rs I buy in bulk.

Of course, this invites the question: "How the hell does it know? The disc is blank, fercrissake."

Well, almost:

Even though general purpose CD-R and CD-RW discs and their consumer audio versions appear for all practical purposes identical, only blank media bearing the "Compact Disc Digital Audio Recordable" (CD-DA Recordable) and "Compact Disc Digital Audio Rewritable" (CD-DA Rewritable) logos can be written in consumer audio recorders. The reason for this restriction is to comply with international copyright agreements. A special Disc Application Code present in the ATIP information of a CD-DA Recordable/Rewritable disc's pregroove wobble identifies it specifically for audio use. Consumer audio recorders are programmed to reject discs not containing the correct code. By adopting this safeguard various countries and other authorizing jurisdictions may selectively apply copyright levies to the price of blank discs intended for consumer audio use while exempting those destined for computer or professional applications.

Now to me, "pregroove wobble" sounds vaguely sexual, and indeed it's possible to see this as a screwing of sorts:

The disc application codes are used to distinguish between discs used for different applications. The two main application codes used are "Discs for Unrestricted Use" and "Discs for Restricted Use." Within the "Disc for Restricted Use" code, another additional encoded identification may be used for special disc applications. One example of this would be the Photo CD.

This is why, for example, you can't use blank data CD-Rs in a consumer audio disc recorder. You must use an audio CD-R. The audio recorder will check to ensure that the blank CD is encoded for audio applications. The audio CD-R isn't any better or different, but will cost more because of copying fees paid to the RIAA.

Ah, yes. The RIAA. The last thing they did that was of any value to anyone other than themselves was the LP equalization curve (500 Hz crossover, 13.7 dB rolloff, and it scares me that I remembered that).

This still doesn't explain why at least one GF-350 I know of supposedly runs just fine with ordinary CD-Rs, but there are such things as running changes, and well, he bought his first.

Posted at 7:48 AM to Entirely Too Cool , PEBKAC