DIGIT TALLY
The 83rd. Convention of the Audio Engineering Society set new attendance records during its October run at the Hilton and Sheraton Centre Hotels in New York. More than 8,000 people registered on the first day, an indication of the explosive growth of professional audio. There was, in fact, some grumbling that the convention was getting too big, and some didn't like the idea of having exhibits in two different hotels. Since the hotels are virtually next door to each other, this really wasn't much of an inconvenience. Personally, the one thing I didn't like was the lack of a lounge area outside the exhibits, which precluded the bull sessions with audio friends that used to be such an enjoy able part of an AES Convention.
As always at this show, there were daunting numbers of new products from every aspect of audio, and it is quite impossible to cover all of them.
As has been true for some years now, digital recording technology predominated, with analog still strong but clearly showing signs of erosion.
Every AES Convention has its star attraction, and I think it safe to say that Sony grabbed the spotlight by introducing their professional R-DAT recorders. Sony's PCM-2500, for studio use, has two chassis, each part approximately 17 inches wide x 4 inches high x 16 inches deep. The top unit houses the tape transport and associated record/playback and indicator circuitry; it weighs 261/2 pounds. The bottom unit is a combination power supply and digital input/output inter face. The PCM-2500 can record at sampling rates of 32 and 48 kHz. Un like consumer DAT recorders, it can also record at 44.1 kHz and thus can be used for CD mastering. The inter face unit has AES/EBU and SDIF-2 and S/P-DIF output ports which provide direct digital connection to Sony PCM 1610, PCM-1630, and DASH-format digital recorders. After transfer to the PCM-1610/1630 format, editing can be performed on the Sony DAE-1100A.
The PCM-2500 has quadruple over-sampling on playback, and a digital filter is employed for each channel.
Switchable emphasis is provided. Error correction is accomplished via double-encoded Reed-Solomon code. On playback, a green LED blinks when an error has been corrected, and an orange LED blinks when an error has been concealed. Balanced analog line inputs and outputs with XLR connectors are provided. Of course, the PCM 2500 offers all the usual DAT facilities of fast selection-locating via multiple search functions and appropriate sub-code and number recording. Maxi mum recording time is two hours, using a DT-120 metal-particle DAT cassette. The PCM-2500 is available now, at $4,995.
Sony also introduced the PCM-2000 R-DAT recorder. This has really excited recording engineers, including yours truly, because it is a portable unit that permits up to two hours of recording with its rechargeable ni-cad batteries. This little gem is just 8 3/8 inches wide x 3 inches high x 10 3/8 inches deep and weighs in at 8 pounds, 13 ounces, including batteries! The PCM 2000 has many special features.
Transport drive is via four direct-drive motors with servo control. Recordings can be made at sampling rates of 32, 44.056, 44.1, and 48 kHz. Double over-sampling with digital input and output filters is employed. As with the PCM 2500, this unit has AES/EBU digital in puts and outputs for direct interfacing with the PCM-1610 and other recorders. It also provides SMPTE/EBU time code. Condenser mikes can be phantom-powered with either 48 or 12 V, and the mike inputs have balanced XLR connectors. Digital audio signals can be synchronized via a word-sync input. The PCM-2000 is quite intriguing. Imagine doing location recording with this lightweight digital recorder and a Blumlein stereo mike, or an M/S, or even a pair of PZMs. The PCM-2000 will be available in the spring at about $7,000.
At the Sheraton Centre, Sony also demonstrated their high-speed DAT contact printing duplicator, which I described in the November 1987 issue.
The system really can duplicate an 80 minute DAT program in 15 seconds! Because of the Copy-code controversy, the situation concerning consumer R-DAT recorders is still unresolved, and audio manufacturers are not importing any such recorders into this country. However, it is important to note that professional R-DAT units are not subject to the same constraints and are likely to be more available here. Also in their favor is the fact that they can record at the 44.1-kHz sampling rate; however, direct digital copying from a CD machine is still not possible because of copy-prohibit sub-code flags in most CDs. It is also rumored that several other companies will enter the professional R-DAT recorder market, among them Nakamichi and Fostex.
While the arrival of professional DAT recorders is of major import, and no one can deny their virtues, they may be a bit too expensive for some recordists. Small studios have found the Sony PCM-F1, in conjunction with a VCR, to be a relatively inexpensive way to get into digital recording. The PCM F1 is a perfectly respectable system which I have used successfully for several years. At the convention, Apogee Electronics (no connection with Apo gee Acoustics, makers of ribbon loudspeakers) showed new anti-aliasing filters which can be fitted into a number of Sony digital recorders, including the PCM-F1. As supplied by the factory, the PCM-F1's filters can produce a rather severe phase shift of as much as 175° at 15 kHz. The new Apogee Electronics filters reduce this phase shift to less than 5°. I understand Apo gee will undertake the modification themselves.
Rowland Research, which makes superb high-end amps and preamps, also has a PCM-F1 modification that includes the Apogee Electronics filters along with worthwhile improvements in the analog circuitry. They modified my PCM-F1 in this fashion, and I must say the increased sonic accuracy and cleanness is quite convincing. De pending on what changes are made, the cost can range from about $450 to $800. Turnaround time is on the order of three to four weeks.
Digital recording has had a profound effect in many areas of audio, including microphones. Early on in the digital age, it became obvious that mikes were going to require updating and redesign for better S/N, lower distortion, and other considerations. Brüel & Kjaer have enjoyed great success with their superb condenser microphones, but users have been restricted to the omnidirectional pattern. Engineers have long wanted a mike of this quality with a cardioid pattern, and at the convention, B & K obliged with the Type 4011 cardioid condenser mike. Its frequency response is rated at an amazing ±0.5 dB from 40 Hz to 20 kHz.
Peak SPL input is said to exceed 158 dB, with less than 0.5% THD at 110 dB.
The mike is powered through a 48-V phantom supply.
Sanken microphones, from Japan, have gained popularity in the past several years. This year, Sanken showed the CMS-7, a lightweight, portable mike with an M/S pattern, designed for use in MTS TV stereo recording and similar applications. With forward-facing cardioid and left/right figure-of-eight patterns, the mike gives good stereo directivity while maintaining compatibility for mono TV sets.
Teldec showed its DMM CD mastering system, which will soon be ready for delivery. The special Neumann lathe and embossing head are not very large or heavy, and since the process does not require a "clean room," the equipment can be installed in any studio or disc-cutting lab. Currently, more than 50% of Teldec's CD production is via the DMM process, and they claim that more than 1,000 CDs are due to be DMM-processed and marketed.
At the AES Convention, RPG Diffusor Systems exhibited Dr. Peter D'Antonio's latest models of his Diffusors and "Abffusors," which are sound-absorbent panels with a claimed rating of 80% at 100 Hz. Concurrent to the AES Convention, Stereophile magazine ran a high-end audio show at the close-by Omni Park Central Hotel. In the room in which CSA Audio, a retailer in Upper Montclair, N.J., exhibited, the efficacy of Dr. D'Antonio's Diffusors and Abffusors was demonstrated. This room measured about 60 x 30 feet and had a 10-foot ceiling. Before treatment, it was typical of such a large space, with a lot of slap and flutter echo. Judiciously placed Diffusors and Abffusors corrected these deficiencies, making Duntech Sovereign speakers, driven by Mark Levinson's superb Cello electronics, sound magnificent.
Editor's Note: I have a bone to pick with several exhibitors who took rooms at the Stereophile Show, and this is a problem which surfaces occasionally at the Consumer Electronics Shows as well. It has to do with a certain attitude toward the public in general in the first case and toward the dealer in the second. What I am objecting to is the "scheduling" of presentations some 20 or 30 minutes apart, in the manner of seatings at a fine restaurant. The doors are closed to all "foreigners" in be tween. In my opinion, this practice is highly arrogant and should be stopped. At one room, people were kept waiting in a stuffy, hot hallway for more than 30 minutes, some 10 minutes beyond the scheduled presentation time. After allowing the throng to seat themselves, the principal speaker proceeded to make a telephone call which lasted a further 10 minutes. In my opinion, it is time to tell these would-be emperors that they aren't wearing any clothes.
-E.P.
(adapted from Audio magazine, Jan. 1988; Bert Whyte)
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