above: Bert Whyte's listening room, in which sound-absorbing Sonex was used in an LEDE installation.
Most audiophiles, even those who are relatively inexperienced, learn early on that the catch-phrase "concert hall realism" is much abused and indiscriminately applied as a quality achieved by almost all hi-fi equipment. Or so the copywriters would have you believe. The audiophile is aware that what he ultimately is trying to achieve is the closest simulation of the live listening experience, whether the music be of the pop persuasion or from the vast resources of the classical repertoire. To this end, most audiophiles continually upgrade their systems to achieve ever higher levels of sonic sophistication.
Some truly dedicated audiophiles spend large sums of money improving their systems. Unfortunately, the acquisition of expensive stereo equipment is no guarantee that the elusive sense of realism will be secured. I have heard some absolutely awful sound from some of the most expensive components. Almost invariably, the poor sound was not the fault of the equipment (although quality can vary widely even in expensive units) but in the manner in which the system was set up and, most especially, the acoustic environment in which it operated. For some strange reason, even experienced audiophiles with high quality stereo systems do not regard the acoustics of their listening rooms as a vital element in playback of music. Too many audiophiles look upon room acoustics as a most arcane subject, and their knowledge of it is at best rudimentary. They admit to a continuing feeling of frustration in their efforts to improve the simulation of the live listening experience.
But there is a new way of acoustically treating listening rooms to achieve this purpose, far beyond what audio equipment can achieve on its own. My awareness of it began at an AES convention several years ago. I was roaming around the exhibits and ran across Alpha Audio of Richmond, Virginia, a company unknown to me. The genial president of the company, Nick Colleran, introduced me to the product they were displaying, an acoustical material known as Sonex. Sonex is an open-cell polyurethane foam supplied in 4 x 4 foot charcoal gray sheets, in 2-, 3-, and 4-inch thicknesses. It is configured in what is called the "indented" or female pattern and the "wedge shaped" or male pattern. (You have probably seen the wedges used in anechoic chambers, and the wedge pattern of Sonex is the same, although the wedges are on a much smaller scale.) Sonex is also supplied in 15 x 15 inch, 2-inch thick wedge-shaped "audio tiles" in silver, blue, brown, orange, and green. Because of the wedge pattern, one square foot of Sonex has 450% more surface area than a square foot of flat foam, and there is almost 100% absorption from 500 Hz to 1.5 kHz with the 4-inch thick Sonex.
Nick Colleran told me about the use of Sonex in recording studio control rooms, in a rather radical configuration known as "live end-dead end" (LEDE) and promulgated by Don and Carolyn Davis of Synergistic Audio Concepts in California. Traditionally, most studio control rooms have their monitor speakers mounted near the front wall and ceiling boundary, surrounded by reflective walls. The mixing console is in the front third of the studio, where the mixer can face the monitors, usually no more than 10 feet in front of him.
The rear side walls and the rear wall are ordinarily made as absorptive as possible. Hence, the "live" reflective end of the control room is in the front, and the "dead" absorptive end is in the rear. Although many aspects of studio control room acoustics are quite controversial, a number of engineers feel the Davis' LEDE approach, in which the "live" end is in the rear of the control room and the "dead" end is at the front of the room, has some unique advantages. Not the least of these special qualities is the very uniform absorption characteristics of Sonex.
When the walls and ceiling of the front of the control room are covered with Sonex, both the absorption and the wedges work together. The wedges provide surfaces to interrupt and break up standing waves so that any energy that might be reflected is diffused. The absorption comes into play along with the diffusion to prevent close-order early reflections which, if the Sonex were not present, would reflect off the hard live wall and combine out of phase with the direct sounds of the monitor. This would produce nasty comb-filter effects, with subsequent frequency anomalies. With the elimination of the close-order early reflections, the mixer hears just the direct sound of the monitors and is not influenced by room acoustics.
After discussing some of the professional studio applications of Sonex with Nick Colleran, I had a brainstorm. It occurred to me that there should be no technical reasons why Sonex would not work in an LEDE configuration in a home listening room. The different circumstances might require some modifications, but I didn't think they would be too difficult. Nick agreed at once and said that as soon as I measured my room and knew the requirements, I could start construction of the first residential LEDE listening room.
First came some basic choices. With orange carpeting in my 12 1/2 x 24 foot listening room, I decided the standard charcoal Sonex would make an attractive color contrast. I selected the 3 inch thick Sonex because it is definitely superior to the 2-inch, especially in the lower frequencies, and is almost on a par with the 4-inch thickness, without its bulk and greater expense.
As a rough rule of thumb, the front dead end of the room should be one-third of the room's total length-in my case, 8 feet. My ceiling height is also 8 feet, so it worked out very nicely to use four of the standard 4 x 4 foot sheets of Sonex on each side wall, and six of the same sheets on the back wall. The 6-inch space was pieced in by cutting strips from another Sonex sheet. For the ceiling, I chose the light silver-colored 15 x 15 inch "audio tiles," both for the desirable color contrast and ease of installation as compared to handling large sheets over one's head! The live end of my room is wood-paneled. Diffusion and the avoidance of long path lengths which would accentuate standing waves are provided by record cabinets on each wall and rear speakers (for use in ambience recovery, ambisonics, etc.). If you undertake construction of an LEDE room, it would be worthwhile to look into several other matters before proceeding. For example, how structurally rigid is the room? Large unbroken areas-the ceiling, floor, and perhaps the walls too-are subject to diaphragmatic "flexing" which can accentuate certain room modes and cause boominess and muddy, over resonant bass. Because of the flimsy nature of most ceilings, nothing much can be done to avoid excessive flexure. However, the Sonex "audiotiles" will afford a little help because of their absorption and diffusion properties. I am fortunate that my listening room is on a concrete slab. In most homes, especially those of recent construction, wooden floors are prime sources of flexure. If your playback equipment is in the listening room with your loudspeakers (the usual arrangement), such floors can be troublesome sources of structure-borne feedback.
One partial solution is to run a 2 x 6 piece of lumber diagonally under the floor joists. This can be held in place and exert upward stiffening pressure by means of one or two adjustable support columns lowered or extended by a worm gear.
Walls can also benefit from stiffening. Dennis Lockhart of Charlotte, North Carolina, built the second residential LEDE listening room. His room dimensions are almost identical to mine and his construction is essentially the same. To stiffen his walls, Dennis cemented together two 3/4-inch, 4 x 8 foot sheets of high density particle board and used enough of these fabricated sheets to do the job. The 1 1/2 inch thick particle board and its weight exerted just the right amount of pressure. There still was some flexure, but the resonance was changed and room modes were better damped for a cleaner bass. If a room is on a concrete slab and the paneling is heavy enough so that it can be screwed and glued to the studs, the spaces between the studs can be filled with dry beach sand.
Next month I'll detail the finishing of my LEDE listening room, report on its performance, and discuss some of the ramifications of this new technique.
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Vintage magazine ADs, June 1982:
Teac
MAGNIFICENT OBSESSION.
In our zeal to build superb tape recording equipment in the extreme, we at Teac are sometimes driven to steal. From ourselves.
The extraordinary X-I000R illustrates this very well. In it, we have incorporated professional features originally designed for our TASCAM recording studio equipment.
These include a linear LED counter which measures tape in hours, minutes, and seconds. A Search To Cue (STC) and Search To Zero (STZ) capability.
In addition, there's Auto Reverse in both directions, in play or record.
The X-I000R, as is current professional practice, employs DBX* noise reduction. An exclusive in home reel-to-reel. And also, as in professional recording equipment, full-tension servos guarantee high stability and accuracy. And low wow and flutter specs of just .03% << 7%2 IPS. All of which add up to an impressive collection of features, we think you'll agree. And if we happened to borrow a lot of them from our professional designs, well that shouldn't bother you one bit.
TEAC-- MADE IN JAPAN BY FANATICS.
COPYRIGHT 1982, TEAC CORPORATION OF AMERICA. 7733 TELEGRAPH ROAD, MONTEBELLO, CA 90640
* dbx" IS THE REGISTERED TRADEMARK OF dbx, INC.. NEWTON, MA.
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Tandberg
YOUR EARS CAN'T APPRECIATE MORE
Tandberg--The European Alternative
It's unlikely there will ever be a better sound producing and reproducing system than the new Tandberg 'Series 3000'.
The only possible alternative will be to re-design the human ear to receive sounds it is incapable of appreciating at present.
The sound quality of the 'Series 3000' is in fact so astonishing it will without doubt become the reference standard by which all others are judged.
Judge for yourself by giving your own ears the pleasure of appreciating this exceptional system at your local Tandberg appointed dealer.
The 'Series 3000' comprises: a cassette deck with Tandberg's patented 'Actilinear' and 'Dyneq' recording systems; the world's finest tuners; a pre-amp that has less than 0.004% THD; a 150W power amp with immeasurable transient overload recovery time; and also a brand new cassette deck TCD 3034 part of the 3000 series for a suggested retail of 49900 TANDBERG OF AMERICA, INC. Labriola Court Armonk, N.Y. 10504
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Cybernet sheds light on Digital Audio Disc Players... WITH LASER TECHNOLOGY
Another technological breakthrough in the Kyocera Series
Recently there has been a lot of stimulating conversation about the newest breakthrough in audio technology...the Digital Audio Disc player (DAD). An innovative concept which utilizes a miniature 4 3/4" diameter encapsulated metallized disc capable of being programmed with over sixty minutes of stereo recordings.
Until now, the talk has been more speculative than factual and production has been limited to laboratory prototypes and demonstrator models. Yet speculations and promises are not the areas that have enabled Cybernet to become a leader in bringing new concepts of high technology to the audio market... and the DAD player is no exception. Our new Model DA-01 Digital Audio Disc Player utilizes the proven principles of laser/ optical scanning found in quality video disc systems, in which there is no contact between the disc and the playback head. By eliminating needle or head drag, wear and the inherent distortion are virtually eliminated. The DA-01 player provides all the superb quality for which digital audio is becoming known, with a full 90dB dynamic range; frequency response of 20-20,000Hz; 90dB S/N ratio and an impressive 90dB channel separation.
Harmonic distortion at less than 0.05% is beyond the limits of audibility.
The convenience features are remarkable. Encoded programming information combined with feather touch electronic controls enables program repeat; scanning; pause; skip; rewind and programmable electronic memory index. A functional LED digital panel displays program, running time and head location.
In all, the DA-01 player fulfills what DAD promises, with a quantum leap in digital audio technology. Look for it soon at leading audio retailers.
CYBERNET INTERNATIONAL, INC.
Seven Powder Horn Drive, Warren, N.J. 07060, U.S.A.
Telephone: (201) 560-0060
Telex: 642529 CYBERNET WARE.
1982 CYBERNET
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Dynavector
World leader in moving-coil cartridges
An even better Ruby.
Through the use of its technology, Dynavector has been able to reduce the size of its ruby cantilever--while dramatically improving performance.
This new moving coil cartridge, the 23R, has one of the world's smallest cantilevers.
Measuring only 2.3mm in length, it is approximately one-third the size of conventional cantilevers.
All musical frequencies travel at different speeds. By using a short cantilever, these frequencies travel along the cantilever from the stylus tip to the coils in near perfect unison.
Thus, the reproduction of sound is like no other in the world.
This shorter ruby cantilever also minimizes undesired resonances.
All cantilevers flex back and forth and set-up unwanted vibrations while tracking your records. By using a rigid ruby, these resonances are greatly reduced.
Because of the cantilever's shortness and material, the 23R's resonant frequency is well above 50kHz. Rubber damping is eliminated and performance is unaffected by variations in room temperature.
In short, Dynavector believes its new 23R has the ability to produce sound with stunning realism, brilliant tonal balance and exquisite detail.
For more critical applications and the ultimate in reproduction, audition the new 17D Diamond cantilever cartridge which utilizes the smallest cantilever in the world.
Dynavector Systems GSA, 1721 Newport Circle, Santa Ana, CA 92705.
(714) 549-7204
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Denon
DESIGN INTEGRITY: The performance that comes closest to our $8000. Separate...
[Pure Class-A, Non-NFB PRA-6000 Preamp iffier and KM-8000 Amplifiers]
...comes in our $450. PMA-750...
...and our $399. DRA-400.
Non-Switching-A AM/FM Receiver with MC Head Amp and Digital FM.
The pure Class-A and Real Drive operation of the PRA-6000 and POA-8000's safely extracts the full performance potential of transistor technology. The elimination of Negative Feedback (Non-NFB) removes the principal cause of Transient Intermodulation and Time Delay Distortions and represents the very latest in contemporary audio design.
Virtually all of this technology is incorporated into the PMP-750. To keep its transistors operating optimally, yet safely, it employs Direct-A 0 db circuitry (capacitorless, non-negative feedback and non-switching). Real-Drive (distortion measured at the speakers is reduced to 1/50!) and Real-Time (passive) tone control. The sound quality is only surpassed by Denon separates costing 13 times as much!
Non-switching A circuitry can also be heard in the DRA-40C Ad/FM Receiver. in addition to its built-in Moving Coil Head Amp and Digitally Synthesized FM tuning. With the DRA-400, Denon has made a new standard of listening quality available to those demanding economy and operating convenience in a compact package.
Denon products share more than game alone.
DENON
Denon America. Inc
27 Law Drive. Fairheld. N.J. 07006, USA.
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Transform your listening room into a professional sound studio. illbruck / usa
P.O. Box 24470 Minneapolis, Minnesota 55424 (612) 934-6179
Now available for the first time to the home audiophile, SONEX was originally developed for use in professional sound studios to help engineers create the best possible recordings. SONEX has also been used by many major component manufacturers for the development and evaluation of their products. In fact, several loudspeaker manufacturers incorporate SONEX in the design of their speaker systems.
SONEX is an acoustical treatment material designed to help you achieve the finest sound quality possible from your audio system. SONEX is highly attractive, very durable, easy to install, and can be placed virtually anywhere. And, unlike many other audio components, you can begin with just a few sections of SONEX, gradually building your listening room into a truly professional sound studio.
SONEX improves your sound in these important ways. First SONEX corrects stubborn room problems such as "boomy" bass, overly bright highs, and "slap echo." Secondly, SONEX smooths out frequency response problems caused by room interaction with your hi-fi system. SONEX also reduces ambient noise, allowing your system to achieve greater dynamic range and allowing you to listen at reduced levels (which helps to keep the neighbors happy). Finally, SONEX gives your room a true professional look and feel, while helping you to achieve better sound reproduction.
SONEX is manufactured into its unique wedge shape from a highly advanced open-cell urethane material. Both the "cells" and the shape of this material aid in the absorption of soundwaves. These "cells" are highly effective in converting sound energy into heat energy, while the wedge design "captures" the sound wave and keeps it from reflecting back into the room. This wedge pattern also creates more surface exposure of these "cells" allowing for up to 300% more absorptive surface area than on flat material.
SONEX has been used by hundreds of people in businesses that depend on high quality sound. Here are a few of their comments: "I highly recommend SONEX for home use. It has been instrumental in helping our salesmen properly demonstrate loudspeakers in our sound rooms." Geoff Court, Owner, Audio Auditions, Minneapolis, MN. "I recommend SONEX to all of my customers that have room problems.
SONEX can improve the sound of systems ranging in cost from several hundred to several thousand dollars." Mike Shotts, Owner, The Soundtrack, Auburn, AL. "SONEX has been the missing link in home audio reproduction. It is the one product desperately needed by home audio enthusiasts. We recommend it highly." Doug Johnson, Executive Vice President, Sound Connections Intl., Tampa, FL. "SONEX is extensively used in our engineering sound room. It is invaluable for the testing and listening evaluation of our state-of-the-art electronic components." Rich Larson, Chief Engineer, Audio Research Corp., Minneapolis, MN. SONEX will soon be available at retail audio dealers across the country. However, you do not have to wait to enjoy the benefits of SONEX in your own listening room. SONEX can be purchased directly from our factory. Each carton of SONEX contains 16 square feet of material and includes an application manual to help you achieve the best possible sound reproduction from your system. SONEX is also perfect for use with holographic units and other image enhancers.
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SANSUI
...and then came the "Z" Receivers.
There was a time when you had to buy separate components to enjoy the control flexibility and power needed for true high fidelity music reproduction.
Not anymore. Sansui now has developed its "Z" series receivers.
Whether you choose the super powered 9900Z, the modestly-sized 3900Z, or any of the four models in between, you get the full-frequency benefits of Sansui's DC-servo amplifier technology. And distortion free FM is assured by genuine digital-synthesized tuning, with the added accuracy of quartz PLL circuitry in our three top models. Twelve convenient instant-tune presets bring in your favorite FM or AM stations (6 of each) at a button's touch.
Real-time spectrum analysis that lets you see the shape of the sound you hear is included in our three most advanced units, along with Dolby FM decoding in the 8900ZDB. All but one of the "Z" receivers include LED displays that instantaneously show you just how much power is going to your speakers. Touch-button FM tuning and volume controls, two-deck dubbing facilities, dual phono cape :. and multi-system speaker switching are all to be found. in various combinations, in the ''Z'' receivers. You'll also find all the additional features you've come to expect from a company that has pushed high fidelity to its limits from its beginnings.
And for all their technological sophistication the six Sansui models in the Z series will appeal to your eye no less than to your ear. Visit your nearest authorized Sansui dealer.
He'II show you why Z stands for the last word in high fidelity receivers.
SANSUI ELECTRONICS CORPORATION
Lyndhurst. New Jersey 07071. Gardena. CA 90248
Sansui Electric Co. Ltd. Tokyo. Japan Sansui
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Now Technics lets you hear nothing but the sound of the source.
Introducing the SV-P100 Digital Cassette Recorder.
No tape hiss. No wow and flutter. Not even head contact distortion. With Technics new SV-P100, they no longer exist. The result-now you listen to the actual music ... the source, not the tape or the tape player.
Utilizing the Pulse Code Modulation (PCM) digital process, the SV-P100 instantaneously translates musical notes into an exact numerical code, stores them on any standard VHS cassette, then "translates" them back into music on playback. Duplicate tapes are exactly the same as the original. Thus, every recording and every copy is a "master." The revolutionary size of the new Technics SV-P100 recorder (17"x 11" x 10") is the result of state-of-the-art semiconductor technology. The built-in videotape transport mechanism brings the convenience normally associated with conventional front-loading cassette decks to a digital application. Tape loading is now fully automatic. And, frequently used controls are grouped together on a slanted panel with LED's to confirm operating status.
Despite its compact size, the SV-P100 recorder offers performance beyond even professional open reel decks.
Since the digital signal is recorded on the video track, the space usually available for audio can therefore be used for editing "jump" and "search" marks. The unit employs the EIAJ standard for PCM recording. And, in addition, editing and purely digital dubbing are easily accomplished with any videotape deck employing the NTSC format.
Technics new SV-P100 is available at selected audio dealers. To say that it must be heard to be appreciated is an incredible understatement.
Technics The science of sound.
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(Audio magazine, Jun. 1982; Bert Whyte )
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