COMPACT DISCANT

As I write, the furor continues unabated about the inclusion of a Copy-code chip in all R-DAT recorders imported into this country. At the present time, the matter rests with the National Bureau of Standards, which will be conducting tests to deter mine whether the Copy-code notch has an audible effect.

While the future of DAT is unclear, the "here and now" of consumer digital audio, the Compact Disc, will soon mark the sixth anniversary of its introduction. With the single exception of CD-Video, which thus far has not generated much interest since its introduction at the 1987 Summer Consumer Electronics Show, the future prospects for CD and its various derivative for mats would appear to be very bright indeed, with significant developments on a number of fronts.

Philips apparently has been making rapid advances towards the realization of a recordable/erasable Compact Disc. The Optical

Disc (MOD) system uses a disc coated with a recording substrate consisting of a number of rare earths, including tellurium, plus cobalt and other, undisclosed materials. The MOD process uses so-called "vertical" or perpendicular recording, wherein the magnetic particles stand at a right angle to the plane of the disc, rather than lying flat, as they do on conventional magnetic tape. In the recording process, a high powered laser beam operating in a weak d.c. magnetic field is modulated by the digital signals. The pulses of the beam actually superheat a microscopically tiny, discrete spot on the magnetic substrate to the point where a reversal of magnetic polarity occurs. Thus, a stream of data pulses, analogous to the data pits on a conventional CD, is "burned" (recorded) into the magnetic surface. A special polarized laser beam of lesser strength is used for playback, and the reflective differences between the areas of normal and reversed polarity on the disc en able the recovery and reconstitution of the original digital information. The MOD can be erased and prepared for a new recording by applying a strong reversed d.c. field, as in conventional magnetic tape recording. Philips is claiming the MOD would be capable of 10 million record/erase cycles! If an

MOD recorder is marketed, it would also be capable of playing convention al CDs, but existing CD players would not be able to play MODs.

Philips has not indicated when an MOD recorder would be available, nor what it would cost. Some observers feel the MOD recorder is a hedge against the R-DAT recorder. Whether this is the case or not, it would have to be competitively priced with R-DAT.

Considering the sophisticated technology of the MOD recording discs, one presumes that they would command a fairly substantial price, say $12 to $15 each. One could also presume that the MOD discs would be able to record up to 70 minutes, consistent with present CD playback. If this were so, R-DAT would have an advantage with its 120-

minute recording capability. On the other hand, R-DAT could never compete with MOD in the number of re cording and playback passes it can withstand, not to mention access time and programming versatility.

Philips has also been working on a number of developments employing CD-ROM technology. Foremost among these is an automotive routing system called "CARIN." It is, in essence, an inertial navigation system; road maps stored on CD-ROMs are displayed on a CRT, and the driver follows the route on the map through preset coordinates. The problem of CRT legibility under bright daylight conditions is claimed to have been solved by the use of a very high-intensity green phosphor. Since it could be dangerous for the driver to take his eyes off the road to view the map on the CRT, a voice chip announces key checkpoint directions. Of course, optimum use of the system would require a second person in the car to act as a "navigator." In the most recent version of CARIN, the metal wheels of the car are the sensors for the satellite navigation al signals. Apparently, the CARIN sys tem has been brought to the point where Philips could market it as early as the spring of 1989!

As an additional comment on developments in CD-ROM, it is fairly well known that storage density is so high that 250,000 pages of text can be accommodated on a single CD-ROM. A friend of mine has just returned from the Japan Audio Fair, and he tells me that Mitsubishi has developed a new microchip which can increase the storage density of CD-ROM a thousand fold. Thus, a CD-ROM disc will soon be able to store a mind-boggling 250 mil lion pages of text! Even with lavish use of graphics and illustrations, one disc could handle the complete Encyclopedia Britannica, dictionaries in dozens of languages, and a lot more; how about a discography of every classical recording that has ever been made, complete with printed scores of all the works recorded on these discs? Of course, the task of entering all this data would be monumental in terms of time and money. Perhaps it could be a labor of love for a new generation of computer-equipped monks and abbots, a sort of medieval discipline brought up to date! Of more immediate interest to audiophiles, the world of music continues to be well served by the ubiquitous Com pact Disc. There have been advances in CD technology and quantum leaps in the availability and scope of music in this format.

In my December 1986 column, I de scribed Teldec's Direct Metal Mastering process for the mastering and production of CDs. Thus far, Teldec has produced about a half-dozen DMM CD projects at their facilities in Hamburg, West Germany. Perhaps a little too optimistically, the Teldec people had expected to make DMM embossing cutterheads and ancillary equipment available to others by June 1987. I have now been given information which indicates that deliveries of DMM CD equipment will commence in January 1988. Capitol Records in Los Angeles will be the recipient of the first DMM CD system in the U.S.; several other major record companies will soon follow, and then gradually such major cutting houses as Bob Ludwig's Masterdisk, Jim Shelton's Europadisc, and Sterling Sound will go on-stream with DMM CD equipment. I have been told that when DMM CDs are produced in quantities of 10,000 or more, significant cost reductions can be expected.

Another interesting claim is that on in expensive CD players, the sound of DMM CDs is superior to that of CDs made in the conventional manner. I hope to acquire some sample DMM CDs soon, and I am looking forward to auditioning them.

When first announced, CD-Video was ballyhooed as "the successor to the 45-rpm single," but with discs at $8 or $9 each and with dedicated players at $500, CDV is not likely to set the world on fire! Much more likely to re place the 45-rpm single is the new 3-inch audio CD championed by Sony.

This little gem is capable of providing up to 20 minutes of music. It can be played directly on any CD player that has an accessible center spindle, including top-loading units. For most front-loading players with motorized disc drawers, an adaptor for the 3-inch CD is necessary; otherwise, it would fall through the loading tray.

Tom Jung, the ever-venturesome president and chief engineer of Digital Music Products (DMP), jumped on the 3-inch CD bandwagon and sent several of us an experimental disc containing selections from his superbly recorded CDs of Flim and the BBs, the Bob Minter Big Band, and New York Cats Direct. The quality is absolutely identical to that found on Tom's standard CDs, and he will be offering a series of these mini-CDs shortly.

Delos Records, too, is offering 3-inch mini-CDs, in a series called "Pocket Classics." The first release, entitled 2001--A Sonic Odyssey, contains music from "Also Sprach Zarathustra" and other classical numbers taken from Delos CDs. A free adaptor for the 3-inch disc is included. Delos has an initial release of twenty 3-inch Pocket Classics drawn from its digital music catalog, and they will be avail able for a suggested price of $3.99 each.

This new mini-CD makes sense to me. Its 20-minute length can certainly provide a generous serving of pop mu sic and can accommodate many short classical pieces or movements of longer works. Most likely, this format will stimulate the production of recordings specially tailored for it. At a price of $3.99, it would seem to have broad appeal for teenagers and for people just getting into classical music.

Finally, while I have, in previous columns, addressed the matter of older recordings reissued on CD, there have been some significant changes in the way many record companies are processing their reissued material. Rather than continuing the earlier practice of just transferring the cutting master which, after all, was equalized and tailored to the dynamic range inhibitions imposed by the vinyl medium, the more conscientious companies are going back to original master tapes and making CD transfers directly from them. Consequently, if you have been holding on to some favorite recordings on LP because you thought they were irreplaceable, you may no longer have to do so: Much of what is being transferred to CD is superior in sound, especially in terms of dynamics and transient response, making the great performances newly attractive.

(adapted from Audio magazine, Dec. 1987; Bert Whyte)

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