In my report on the Audio Engineering Society's 61st convention last month,
I gave priority to the exciting new developments in digital technology. I sincerely
believe such concentration is completely warranted in light of the profound
changes that will be wrought when the audio industry converts to the digital
realm. These changes are already in progress, and the onrush of digital technology
will not be impeded by the cynics and nay-sayers and those who hide their heads
in the familiar and comforting world of analog audio. How well I remember the
die-hard mossbacks of the mono phonic era who had to be dragged, kicking and
screaming, into the realm of stereophonic sound!
New Tape Speed
While the evidence on every hand indicates that digital technology will become the dominant factor in audio much sooner than most engineers anticipated, it is also obvious that analog audio is firmly entrenched as our operating technology, and there will be ongoing developments in analog audio for some time to come. Some significant examples of progress in analog audio were on display at the 61st AES convention at the Waldorf. Per haps the most eyebrow-raising item was the MCI introduction of their JH 32 studio tape recorder, utilizing 32 tracks on three-inch wide magnetic tape, with standard tape speeds of 15 and 30 ips, and the entirely new tape speed of 20 ips. A number of companies have been experimenting with studio tape transports designed to handle tape widths beyond the 2-inch industry maximum. Several years ago when I visited the Studer plant in Switzerland, they had a 3-inch transport.
They and some others apparently didn't pursue these projects, and there were some reports concerning problems of tape skew with ultra-wide tape. Some years ago I struggled to lift a reel of six-inch wide tape, which I was shown by a tape manufacturer and which I fervently hoped was a gag! Evidently MCI has conquered any tape skew problems, since the JH-32 is a production model. The 20-ips speed is an interesting development inasmuch as some people with variable drive equipment on their recorders have been using them to provide speeds of 22-23 ips, in the interest of tape economy, as compared to the usual 30 ips. I have no idea what they did to modify equalization for these oddball tape speeds. In providing 20 ips as a standard tape speed on the JH 32 recorder, MCI presumably has worked out complementary equalization. The combination of the 3-inch tape and the 20-ips tape speed evidently allows 32 tracks to be recorded with the equivalent fidelity of the MCI 24 track/2-inch recorder. While quite a few studios have been running two 24-track recorders in tandem, with 2 tracks used as control tracks in the lock/sync mode for a total of 46 tracks, some engineers feel this is a rather cumbersome expedient. No doubt many devotees of multi-track recording will welcome the flexibility afforded by this new MCI JH-32 recorder, but you can bet that some "far out" engineer will realize that two of these JH-32 units can be "synchro-locked," for a mind-boggling total of 62 tracks! While we are discussing multi-track professional tape recorders, if you have ever done a complete alignment on a two- or a four-channel tape recorder head, you can only imagine how tedious and time consuming a task this is for a 24-track head assembly. An interesting new device for alleviating this problem is the Promix One multi track head mounting assembly, manufactured by Grandy, Inc., of Fairfield, N.J. When the standard head mounting is replaced by the Promix One, the head adjustments for azimuth, zenith, tape wrap, and track height are independently handled by a linear-type control, with easy-to-handle knurled knobs for most of the adjustments, rather than the usual fumbly Allen wrenches. Grandy also builds a complete line of replacement heads and is also well-known for its head-relapping services.
In the area of smaller open-reel tape recorders, Technics was showing its RS-1800, an offshoot of its RS-1500 isolated-loop recorder, featuring tape speeds up to 30 ips, quartz-lock pitch control, and automatic adjustment of bias and equalization for the various tape formulations. Tandberg was showing its TD20A open-reel recorder, which we reported on some time ago, and which, if you recall, can handle the new metal particle tape. Unfortunately, the tape was a "no show" and thus no demo, except for a fine presentation with conventional tape.
Otari has an open-reel deck, the MX5050-B which also features automatic equalization adjustment, a facility that appears to be gaining favor and which will feature prominently in quite a number of cassette recorders at the WCES at Las Vegas.
Metafine Tape
Speaking of metal particle tape, one of the most impressive demonstrations at the AES convention was Inovonics' duplication setup, which had masters duped onto 3M Metafine cassettes, using both Dolby and dbx noise reduction. If you confine the results to Dolby which, after all, is the noise reduction system most commonly in use in cassette recorders, the approximately 3 to 5 dB more output afforded by the Metafine permits a S/N ratio and dynamic range that dearly can put pre recorded cassettes into head-to-head competition with the best disc recordings. Of course, it was quickly pointed out, that while these Metafine dupes were of very high quality, the demonstration was strictly an exercise in technology, as it is highly unlikely there would be any demand for pre-recorded cassettes using metal particle tape.
This assumption is based on what the consumer would have to be charged for such a product, in consideration of the high cost of the metal particle duplicating tape, and the equipment modifications that would be necessary in the duping setup. Well, I disagree 100 percent with this idea. In the first place, as we go to press we have word from 3M on the pricing of their first Metafine cassettes. It is a pleasant surprise to report that the prices are substantially less than anticipated...the C60 Metafine to sell at $6.95 and the C90 to sell at $8.95. Now remember, these are the retail list prices to the consumer. Remove the retailer's profit, jobber's profit if that applies, and the quantity discounts which would be available to a duplication house, and the price, while still quite high, would not be all that deterring.
Especially since I can virtually guarantee to the recording companies that the audiophiles will gladly pay a premium . . . and I mean a substantial premium ... for metal particle pre-re corded Dolbyized cassettes of really high quality. And that is what a metal particle pre-recorded cassette would be . . . a premium product for the audiophile. Give him a cassette with S/N ratio and dynamic range that can be superior to a disc, that does not have the ticks and pops, that does not have the wear problems or the warp problems of a disc, and believe me, oh thou record company executives, you have a highly salable product.
Amplifiers
Amplifiers at the AES conventions are usually of the type involved in PA applications, with a smattering of types of interest to the audiophile.
This year, there was a change in the overall coverage, with more emphasis on high quality units for the audiophile and monitoring markets. Sansui has formed a Professional division to market its new high power B1 amplifier, for which slew rates as high as 1000 volts/ uS are claimed. (Production models are said to run about 300V/ uS.) Pioneer, taking a venture into the separates market, was showing a new non-switching amplifier, the SA8500, with a dynamic biasing circuit a la Threshold, to afford Class-A type performance of 150 watts/channel.
Class-A performance claims are also made for new amplifiers from JVC (again with some innovations to achieve Class-A specs), and Technics was again showing its huge 350/watts per channel "Class-A Plus" amplifier.
Both Crown and BGW showed new "slimline" power amplifiers both with 50 watts per channel output rating.
Not too much in the way of new loudspeakers at the AES convention.
However, much interest was created with what is said to be the first really new horn driver in many years, the Pioneer TAD TD4001 which has a four-inch voice coil, with four-inch beryllium diaphragm. Designed by Bart Locanthi, this driver is said to be the first computer-assisted design for a horn driver, with performance said to surpass the legendary Western Electric drivers. Osawa was showing the well-known British LS35A BBC-type monitors made by Chartwell, along with a subwoofer, the SW-135, to augment bass response. Also demonstrated was the Chartwell PM450 studio monitor system, bi-amplified with built-in Quad 405 amplifiers. When I was a guest of Decca Records during my re cent recording of the London Philharmonic, they were using this Chartwell monitor in their listening room, and it was a smooth and impressive performer in many respects.
Time Delay Units
I have reported on various delay units in past columns, including the excellent AKG BX20 and BX10 delay/ reverb units. I related how I had seen a relatively inexpensive prototype unit at the AKG plant in Vienna about three years ago, but alas, it never appeared. At the AES convention, AKG was showing its BX5 2-channel reverberation unit, somewhat simplified from the earlier units, but nonetheless offering reverb times of one, two, and three seconds with provisions for mixing from full dry to full reverb. At a proposed $1000.00, it is half again as much as the prototype I saw, but it does more, and this price is substantially less than the BX10's.
As for the ubiquitous digital delay lines, some of the units announced at several previous conventions are now reaching production. The Lexicon Prime Time Model 93 at just under $1500.00 is now reaching dealers. I am still waiting for them to produce their digital reverb unit, which, in the demonstration I heard a year ago, produced a very realistic approximation of a concert hall ambience.
For the well-heeled Nagra owner (and you have to be in that category to own one!) there is now available from Future Film Developments in London, a portable Dolby A noise reduction system. Specifically for the stereo Nagra 4S, it mates with the recorder, weighs under 10 pounds, and is battery-powered to afford 10-hours re cording in mono and six in stereo.
When the capstan motor is not driving the tape, the system is on standby and uses little power. It's all yours for $2600.00.
As usual, tons more at the 61st AES ... I could write a book. I am off to the WCES at Las Vegas, where the hi-fi industry is going to mount a major effort to get out of the sales dol-drums that it is presently in. At last count, I have announcements on seven new cassette decks capable of handling metal particle tape, and I'm sure there will be others at the Show. It is a trend, for sure!
(Source: Audio magazine, Mar. 1979; Bert Whyte)
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