As noted last month in the first part of my report on the 70th AES Convention
in New York, the resolution to establish digital recording standards means
that digital recording has finally come of age. The introduction of new digital
recording equipment into the professional marketplace had been proceeding
at a moderate rate, with a certain amount of timidity evident in some manufacturers'
attitudes towards digital technology. Now, with the imminent establishment
of digital re cording standards, the "digital derby" will be off
and running. Apparently, there were quite a number of manufacturers who anticipated
the standards, for there certainly was much new digital equipment on display.
I reported on several items last month, and herewith a run down on more new
digital devices.
Not all the digital equipment was in the form of recorders. Sony drew large crowds with a demonstration of their CD (compact disc) DAD (digital audio disc) player, which was jointly developed with Philips. The device has been demonstrated before, but this time it appears to be close to being a production proto type. The laser tracking is via a solid state laser diode, and the digital-to-analog circuits are apparently in the form of a Sony-developed LSI chip. Although the music played during the demo wasn't my cup of tea, it was obviously very clean and of wide frequency range.
albeit not the kind which would show the 90 dB dynamic range of which the CD disc is capable.
The CD system is slated for introduction in Japan this fall, but the present economic situation in the audio industry might just hurry things along a bit. Polygram is supposed to have a CD soft ware plant in West Germany ready for production by June, and Sony says that the LSI chip production is proceeding ahead of schedule. Thus, an earlier introduction of the CD system isn't out of the question, especially since Polygram (and supposedly CBS/Sony) would have "blades for the razors!" Not to be outdone, Pioneer also showed a prototype CD digital audio disc player. Pioneer had previously developed a proprietary laser-scanned digital audio disc system but decided to become a licensee for the Sony/Philips CD system. Their player loads the 4.7-inch diameter digital disc in a "disc well" on the front panel, somewhat in the manner of a front-loading cassette deck. A semi conductor laser is used to track the CD disc, rather than the larger gas laser Pioneer uses in their video LaserDisc player. According to Pioneer, the CD player has extraordinary random-search capabilities and can be ordered to search out any program selection in three ways: By program number, by elapsed playing time from the start of the disc, or by elapsed playing time in a given musical selection. Even such a complex search function as, for example, ordering the player to commence play at 2 minutes 10 seconds into the third selection of the disc takes only a few seconds to accomplish. All commands are visually con firmed via the player's front-panel pro gram and time displays.
Technics was on hand with some very practical new digital devices. They feel, and rightly so, that fancy digital recorders shouldn't have to accept analog signals from such things as mixers, equalizers, and reverb units. Thus, they introduced their Digital Audio Mixer/Equalizer and Digital Audio Reverberator with memory. The mixer/equalizer handles digital signals with eight inputs and two outputs. (There also are two analog out puts for monitoring.) Full panning and level adjustment are provided as well as facilities for special effects via AUX out put terminals. The fully digital equalizer uses recursive-type digital filters to allow high-speed real-time data processing of complex digital filtering operations.
Linearity is maintained with an internal 35-bit capacity--more than twice the usual 16-bit signal to be processed. The equalizer affords high- and low-frequency roll-off and shelving, as well as mid range cut and boost. Quantization is 16-bit linear, and while the sampling rate on the device is currently at 50.4 kHz, you can be sure it will be changed to the new proposed 48-kHz standard.
The Technics Digital Reverberator has two digital input and two digital out put channels. Initial delay times range from 0 to 155 milliseconds, while reverberation covers 0 to 10 seconds. Quantization is also 16-bit linear with a 50.4-kHz sampling rate at present. Low, high and midrange reverberation can be applied separately to simulate the absorption and reflection characteristics of particular acoustic environments. The de vice is equipped with three programmable memories, each of which can store four kinds of data: Initial reflections and later reflections in low, mid and high range. The memories are nonvolatile, which means you won't lose them during a power failure, and settings can be held for subsequent mix-down sessions. The system features very natural reverberant generation, without the colorations characteristic of plates, springs, etc. A remote control is available.
The Studer company has been quite active in digital equipment. While their multitrack digital recorder won't be introduced until the 71st AES Convention in Montreux, Switzerland, they did show their interesting new Digital Sampling Frequency Converter (SFC-16) in New York. This unit makes possible inter change and recording between digital recorders with differing sampling frequencies. For example, if a recorder has a 44.056-kHz sampling rate and another digital recorder has a 50-kHz sampling rate, they can successfully be converted, up or down, through the Studer SFC-16. The converter accepts arbitrary sampling frequencies, and since it operates strictly under control of the clock signals, no programming is required.
The SFC-16 will permit dubbing from one digital recorder to another without leaving the digital domain. In other words, it makes digital-to-digital dubbing possible. In addition to format conversion, one of the major uses of the SFC 16 will be in mastering to the 44.1-kHz sampling frequency of the Sony/Philips CD digital audio disc.
Of course, in the midst of all this digital activity, analog audio is still very much with us. In fact, at the Studer exhibit, engineers were casting lustful looks at the Studer A80 MK Two, an update of their well-known analog magnetic recorder now featuring two-channel stereo recording on half-inch tape. Ampex introduced this format several years ago, and it has become quite popular. It is claimed that in the A80 MK Two, with all electronics nicely tweaked and using a hot tape at 30 ips, the signal to-noise ratio approaches 80 dB! Speaking of Ampex, they are helping to keep analog magnetic recording alive.
They have a new machine, the ATR 800, which is specifically designed for the international broadcast market.
There are certainly features galore that will appeal to broadcasters, a "dump edit mode," cue amplifier, and quick change heads in mono, stereo and four-channel formats in both quarter-inch and half-inch tape widths. The ATR-800 is switchable between NAB and IEC setups, including bias and level changes as well as equalization curves. There is a universal power supply, and single point "search-to-cue" is standard, as is three-speed operation. The ATR-800 does have a capstan/pinch roller drive, but it is under closed-loop servo control. There are many other standard features as well as several options, things like a built-in tape marker, a tape cutter, and a noise-reduction interface kit for Dolby or dbx.
Price begins at $5,450.00 for the basic two-channel recorder, and delivery is expected by the time you read this.
JVC exhibited their DAS 90 digital recording system, but they also showed photos and details of the newly modified and updated JVC Cutting Center in Los Angeles. In addition to a special direct-drive motor for the Neumann cutting lathe, they have a newly designed CH-90 cutter head. This unit features a "rocking bridge" cutter bar system, which has no cantilever and is extremely stable as to phase and crosstalk characteristics. A highly heat-resistant (250° C) material is used for the moving system which, combined with a double-chambered helium cooling system, permits high dynamic ranges with a maxi mum velocity of a staggering 127 centimeters per second! This is also possible due to the new CA-9011 cutting amplifier, using their "Super Linear" circuit which puts out a mere one horse power (800 watts) per channel! I have previously reported on the JVC UHOR (ultra-high quality) 200-gram "super record." Here is how one was recently produced. JVC took their DAS 90 digital recording system to Moscow and recorded the Moscow Radio Symphony Orchestra in Stravinsky's "Rite of Spring." Then it was cut with the new cutter head and cutting amplifier and pressed on a UHQR disc. The result is rather terrifying --there are monumental transient pulses on this disc that present a formidable challenge to the tracking abilities of even the finest phono cartridges. Unfortunately, this recording is not permitted to be sold in the United States; if you want a copy, you must pick it up in Japan or arrange for someone there to send it. But if you do manage to get one of these recordings, I think you will find JVC has made a significant advance in the state of the art in disc processing. It's a doozy!
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(Source: Audio magazine, Mar. 1982; Bert Whyte )
Also see: Dr. Thomas Stockham on the Future of Digital Recording (Feb. 1980)
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