Copycode & the Future of DAT Peter W. Mitchell Asks: Is DAT Doomed?
The copy-protection debate has created the impression that if DAT recorders are sold without Copycode scanners, everyone could start churning out perfect digital copies of CDs. But in fact the design of DAT already incorporates two basic obstacles to digital CD piracy: copy-protect flags and incompatible sampling. Thus the proposed imposition of Copycode scanners in DAT recorders would seem to be a superfluous third level of protection.
The coding standard for the Compact Disc, established in 1981, provides for an optional copy-protect "flag" bit in the digital data stream. From the outset the design of DAT has included a circuit that automatically inhibits recording if an incoming digital signal contains this flag bit. This, the designers presumed, would provide ample protection against amateur piracy of copyrighted recordings.
Originally the digital sampling rate of DAT was set at 44 kHz, like CD, and digital outputs were added to CD players in order to facilitate direct digital taping of any CDs produced without copy-protect flags. But two years ago an international agreement set 48kHz as the standard for professional digital recording, and DAT manufacturers were persuadedreluctantlyto adopt the higher rate in order to provide a second level of protection against home copying of CDs. DAT recorders designed for professional use can record at either 48 or 44.1kHz (so that they can be used to make master tapes for CD production), but consumer DATs are locked out of 44kHz recording. They cannot record the digital code from a CD even if the copy-flag protection is somehow bypassed or defeated. This, optimists thought, would take care of any remaining piracy worries among American record-company executives.
Why didn't it? The enthusiasm of DAT proponents played directly into the paranoia and greed of the big cheeses at the RIAA (the Recording Industry Association of America). Like the first ads for the CD, which claimed that it would provide "pure and perfect sound forever," early DAT publicity emphasized that it would make flawlessly exact copies of every sound. If that's true, the RIAA argued, digital copying is not the only threat; the DAT could make an exact copy of a CD through its analog inputs, and each DAT tape could then serve as the source of endless digital clones. As a practical matter, the first two levels of copy-protection might as well not exist. Thus the ground was paved for the entry of the CBS "magic bullet"the 3.8kHz notch filter and detector that promise to block analog copying from CD to DAT (and, eventually, copying of recordings in any medium).
Of course, people who care enough about sound quality to pay $2000 for a tape recorder won't be satisfied with analog copying as long as the possibility of digital dubbing is tantalizingly just out of reach. In Japan the DAT, even without the mythical Copycode chip, is viewed as a crippled product because of its inability to make digital-to-digital CD dubs.
When Sony bought CBS Records in November (footnote 1), the audio industry breathed a collective sigh of relief because of the widespread assumption that the new owners would force CBS to drop its advocacy of Copycode notch-filtering. But that probably won't happen right away; Sony announced its intention to leave policy-making in the hands of current CBS Records executives, at least for now.
Regardless of the outcome of the Copycode battle, it seems clear that DAT is not going to become the dominant home taping medium any time soon. The CD may supplant the LP, but DAT won't replace the mass-market analog cassette; it is simply too expensive and is likely to remain so for the forseeable future. It would be more accurate to view DAT as the logical successor to the Revox (and other) 2-track open-reel stereo tape recorders that have long been the standard for semi-professional recording, basement studios, and on-location recording of concerts for delayed radio broadcast. Recognizing this potential, Sony introduced two "professional" DAT recorders at November's AES conventiona $5000 AC-powered model and a $7000 portable. Pro DATs have also been announced by Fostex and Nakamichi.
Meanwhile, since DAT seems destined to be a slow-growth medium, developers are exploring other uses for the technology, and there is much enthusiasm for the idea that a DAT with more robust error-correction would be a splendid storage medium for computer programs and data. Its capacity (over 1000 megabytes) would be double that of the CD-ROM, and it would be much less expensive than the user-recordable optical discs now being developed.Peter W. Mitchell