Behind The Scenes (Sept. 1991)

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BATTLE OF THE FORMATS


With nine years to go before we enter the 21st century, there is a great proliferation of new developments and technologies that will profoundly affect the audio and video industries. It would probably be more accurate to say they will affect "home entertainment electronics," considering the ever-increasing interaction between audio and video.

Most of the new developments and devices utilize some new, advanced digital technology such as magnetic, optical, or thermal recording of CDs and various forms of digital data compression in audio and video systems.

Unfortunately, a number of these technologies conflict with each other, and each proponent is trying to emerge with the absolute standard format for its particular medium. Currently, the emphasis is on digital recording devices such as the R-DAT, DCC (Digital Compact Cassette), and the MD (Mini Disc). And there's also the Dolby S type analog cassette system.

In spite of all the travails with the RIAA and copyright organizations, R-DAT recorders are now generally available to consumers in the United States.

But even with list prices as low as $750, the R-DAT units have not been selling in any significant quantities; it seems that the R-DAT format is now only widely accepted by professional recording engineers. The limited catalog of prerecorded R-DAT cassettes and their high prices due to one-to-one duplication apparently have adversely affected R-DAT recorder sales to the general public. Nonetheless, no one questions the capability of R-DAT recorders to provide wide-range, high-fidelity digital recordings.

Philips' Digital Compact Cassette recorder (DCC) is scheduled to be introduced in the spring of 1992. The concept is that of a unit which can play conventional analog audio cassettes but also record and playback a Digital Compact Cassette on the same machine. Some future DCC units may record analog cassettes as well.

The DCC is the same size as the analog cassette but is of a different, more complex construction. The digital recording heads are stationary, with eight tracks plus an auxiliary track for each stereo channel. (The DCC, which uses chrome videotape, is not turned over but reverses automatically.) The heads are made by lithographic techniques similar to IC chips. The head gaps are extremely small; tracks are recorded at 185 microns and read at 70 microns to compensate for mechanical irregularities in the tape drive.

Philips has developed Precision Adaptive Sub-band Coding (PASC) for DCC. The sound is sampled and digitally processed into 32 bands. Each band is separately coded with a variable number of bits depending on the content of the signal, averaging out to four bits. The recording speed is the same 1 7/8 ips as analog cassette, and the sampling rate is 48 kHz for record, as in R-DAT units. (For more information on DCC see page 32.) Philips states that prerecorded DCC tapes will be available with duplication done at the usual 64 x speed, with slaves using the special DCC stationary heads. The SCMS "one digital copy only" system is included in the circuitry. Philips also plans to introduce portable and car DCC machines.

Sony's new MD (Mini Disc) system is an ultra-sophisticated digital recording system. A small 2 1/2-inch disc, coated with rare-earth alloys, is encased in a 2 3/4-inch square plastic caddy only 1/8 inch thick. When inserted into the recording deck, a rectangular plastic tab on the caddy is slid aside, allowing the disc to be scanned by the infrared laser for recording or playback. When recording or playback is ended, the tab is returned to its original position.

Thus, there is no direct handling of the disc, avoiding all contamination. Recording is a complex process, in which the infrared laser heats the rare-earth disc coating in the presence of a strong magnetic field. Data-compression techniques are used, with psycho acoustic masking a part of the process. As this system is said to slightly compromise the sound quality, the MD is not intended as a replacement for CD and its main use will be in portable and car units. A clever memory circuit makes the MD particularly good in' combating the bumps and vibration in cars and portable use. If the laser "jumps the track," a memory chip, already loaded with 3 seconds of music, will permit uninterrupted playback, and, during that time, the laser beam will have been refocused on the proper track. In other words, the music is really being output from the memory buffer while the memory is being continuously updated for 3 seconds of music (save in the case of bumps). The MD can be replicated in standard CD plants; thus recorded MDs should be readily available. Blank MDs will permit up to 72 minutes of recording. In the near future, Sony might incorporate what they call an Irister circuit in the MD. This is a system in which the infrared laser and an extremely small lens can reduce the size of the light spot in recording to improve packing density by a factor of six, so that the 2 1/2-inch MD could provide over seven hours of recording. Further down the line, Sony is expecting to develop a blue laser, which would increase recording density by a factor of 20. The tiny MD would provide a mind boggling 24 hours-a full day-of recording! It is interesting to speculate that an artist like Frank Sinatra could have about 320 of his songs recorded on a single MD! The problem, of course, is that performing royalties would make this MD prohibitively expensive. Sony's MD system is due to reach the market in the fall of 1992.

After all this high-flying digital technology, let's look at the latest offering from Dolby Labs, long a champion of analog audio. Dolby S-type noise reduction is the consumer version of their highly successful Dolby SR (spectral recording) professional noise reduction system. You may have noted that quite a few movies are now using Spectral Recording for their soundtracks. Dolby S-type is derived from SR and has in common with it such developments as having both fixed and sliding bands, spectral skewing, anti-saturation, and control of modulation noise.

S-type provides 24 dB of noise reduction at high frequencies and 10 dB at low frequencies. Headroom at high signal levels is considerably improved at both low and high frequencies.

Dolby Labs claims that cassettes with S-type NR can be played back on Dolby B cassette decks with good compatibility. In this case, although there is an audible reaction in dynamic range, the sound is said to be spectrally balanced and dynamically stable.

The same claim is made for S-type playback through Dolby C circuitry.

The late Howard Roberson, Audio's highly respected authority on compact audio cassette technology, tested S type recording on an early Teac Esoteric deck (June, 1990), was quite impressed with the system, and verified the Dolby claims, stating that, "Overall the sonic compatibility with Dolby B and C NR was definitely better than I thought it would be." Dolby Labs also claims that S-type is far more tolerant of level and response errors than Dolby B or C NR. Roberson deliberately misadjusted bias and level calibrations several different ways and confirmed Dolby's claims.

The compatibility of S-type with Dolby B and C NR is of great importance in respect to prerecorded cassettes. Duplicators all over the world are set up for Dolby B replication, and they would be very reluctant to set up S-type duplication facilities if S-type cassettes could be played back only on S-type cassette machines. Neither they nor the audio dealers want a double inventory problem. There is, at present, a very small population of S type cassette decks, but in early tests by Warner Bros. Records using Dolby Labs' new professional Model 422 reference encoder for B, C, and S-type NR, the S-type cassettes got a very positive response. Negotiations for S type cassette duplication with several record companies are ongoing and look promising. At last report, Dolby Labs had licensed more than 15 companies to manufacture S-type cassette decks. The S-type circuitry has been reduced to a single chip-the Sony CXA 1417 IC--and is now in full production, so more companies are expected to go into S-type deck production. However, there is a proviso: Dolby Labs will not grant a license for S-type use unless the manufacturer's decks meet new Dolby Labs parameters for mechanical tape-handling performance with improved wow and flutter specs and the capability of more precise azimuth adjustment.

Irrespective of the individual merits and drawbacks of R-DAT, DCC, and MD digital recording formats or the Dolby S-type analog recorders, in terms of performance and ergonomics, all are just at the starting gate in the marketplace and are jockeying for position. Any consumer recording format will likely perish or flourish on the availability and cost of its particular prerecorded programs.

I dare to ask: If there were no prerecorded music for any of these four new recording formats, how many units could be sold solely on the basis of their recording capabilities?

In essence, what kind, and what amount, of recording activity is actually done by either audiophiles or the average consumer? Considering the millions of blank audio cassettes sold every year, there is a lot done on cassette decks. I would venture to say that a majority of this activity is in the youth market and oriented to pop music. The kids exchange and copy prerecorded cassettes and CDs borrowed from friends. They record pop music from radio broadcasts. They probably do more live recording than any other group, even though most of it is of home-brew rock bands. It is claimed that pop music accounts for 95% of the total record market in the United States. That is a formidable group, especially since most of the people in that group record on audio cassettes.

While acknowledging that a large part of this huge market would not have the ancillary hi-fi system to appreciate the higher quality of Dolby S-type recording, it still represents a definite plus for Dolby Labs' new format.

One must ask, in these circumstances, how many people in this pop music group will have an interest in and will be able to buy these more expensive digital recorders? While the CD is the premier music format, many people still consider the discs expensive as they cost an average of $13 or $14 each. DCC tapes and MDs are likely to be less expensive than CDs, and this may incline more people to these formats. At present, prerecorded R-DAT tapes are few in number and too expensive for most people.

For the 5% of the record market who want classical music, and ostensibly this group includes many audiophiles and others interested in high-quality recording, all of the new recording formats would be competitive. But here again-what would they record? Forget live recording, requiring good mikes, requisite skill, and opportunities to record musically worthwhile groups.

There are precious few live music concerts to record off FM. Recording CDs would be pointless, except for "customized" programs to play back in cars or on portables. And recording at a live concert can get you arrested! I certainly cannot be described as anti-recording. For over 40 years I have been in every segment of recording activities, which includes engineering many pioneering commercial stereo recordings. Undoubtedly, many people enjoy recording, and more power to them, but as an activity on which to base a market for recorders of any type, it is limited.

So, we are back to square one--high-quality prerecorded music is the rock-ribbed foundation of any recording format, digital or analog. One thing is certain: Neither consumers nor dealers will support multiple inventories for differing tape or disc formats. Something has to give. So let the games begin!

(adapted from Audio magazine, Sept. 1991; Bert Whyte)

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