I turn to the following expression with considerable compansion. And if you find those words odd, they merely reflect the gist of my thought which is, can we compand or use our home audio system to good advantage as per a burgeoning of recent new equipment, or will things be OK if we leave our music as it is, just as it comes from the audio package-tape, disc, or broadcast? The answer is yes ... both ways. Some people would put things the other way around: should we compress and expand; but it's all the same to me since expansion is but the mirror twin of compression, two processes which, when all goes well, are one and add up to zero. Which is exactly what the whole thing is about.
The villain of this compransion, is the left-handed twin (gauche, sinister), compression. Compression of signal is a necessary evil in many areas of audio signal processing to make things fit into the audio frame.
Nobody does it for fun & games (though they'll do it for background). On the right hand (dexterous, adroit, righteous), we have expansion, the saving grace, the redeeming feature and, if I many say so, also inclined to take off on its own, minus twin. It's fun to expand.
When it comes to transmitting music through the interface between acoustic and electronic there is no room for anything but careful compromise, which means compression, limiting, and other negative-type circuitry. Various equalizations are part of the picture, but compression is the main thing, at least as of my present concern, and it isn't simple.
Even live orchestras, I have to remind you, must sometimes acoustically compress their own dynamic range, repress their natural expression, even before the microphones get involved; that's one way to do the necessary job. And a nice sub-question is, should we expand them electronically in our homes, to make them play the way they might have played, if--? Well, I can tell you right now that that particular expansion will never work. The only way to make musicians sound as if they are playing LOUDER is to have them play louder ... overtones, physical effort and all that. You cannot make a soft trumpet sound like a loud one by turning up the volume.
But if we merely bring them back to normal, after electronic compression? That is another story and it should work just fine--if we can do it. That's where the dynamic range expander comes in. A mirror-type circuit, its expansion of the volume range matching the compression built into the audio signal. If it works we should have zero, the same thing the players played.
I recently read with pleasure our Equipment Profile on the dbx Model 128 (Audio, Nov. 1977, pg. 106), a piece of equipment which is highly involved in this sort of mirror operation. If there is anybody in the biz who knows the ins and outs of compransion, it must be dbx, and this model is doubly involved, once for the traditional dbx two-stage noise reduction (via mirror compression/expansion circuits) and again via a range expander, hopefully to compensate for the compressions that undeniably are there in the long chain of electronics that leads from living music to the living room. Compransion is a versatile principle with many uses.
Now it happens that I had another dynamic range expander right in my own home circuit, built into a piece of equipment loaned to me for another purpose. It will be nameless because it is not currently in production--but do you think I didn't try it? I try everything. I listened to normal recorded music with this thing in my circuit, to see what would happen, this time.
In all the years I have been writing I had not yet heard one of these expander devices that, however noble the intentions, sounded right.
Instead, they have left me thoroughly disturbed, for they seemed always to destroy that easy sense of "presence" that is the very basis for good listening; they intruded, they called attention to themselves, like a amiable puppy that comes in and won't leave you alone.
The idea is splendid but it never seemed to work out in practice. I just found that I like the plain music better, compressed or not.
So I tried this one, now some years old-and it was the same. I used the helpful controls, I tried to fool myself by leaving the thing on and hoping to forget it was there next time--no go.
The best setting was zero. Out of the circuit. But--? Hope never dies! Even so, the idea is good, it ought to work.
In a way, I was disappointed. Because I rejoice when somebody, at last, manages to do the heretofore impossible. It happens right along, it can happen again. Reason says that this sort of expansion just has to work, if it is done right, especially now, when we can do so much more that we useta could.
The problem, of course, is that here we are dealing not with one fixed, known compression, to be precisely matched by a fixed and known expansion. Far from it. There are almost as many compression parameters as there are record companies, broadcasters, tape machine builders, and disc cutters; not only that, one compression may be superimposed upon another, in a different place and time, and indeed probably is. These gents don't even know each other to speak to, let alone compare notes on compressions. All in all, I find it astonishing that their final products get through to us with any sense in them at all, what with so many operating circuits at so many places in the audio chain. In fact, I have a healthy respect for our record producers (and even some of our broadcasters) for their practical know how.
If compress they must, then they have learned to do it gracefully.
So our expansion mirror circuit is tackling the impossible, which is to match exactly all of these alterations in the sum total as represented in the signal which reaches your home. The mirror isn't flat. It's full of sonic wriggles and wavers and bumps. That's what I have been hearing--so far. The compressions themselves, again, are generally smooth and unnoticeable, even if they are there. And yet--? I am beginning to see, after all these years, how it could be done. And I am beginning to suspect that the more recent manufacturers have figured it out.
Maybe the impossible is no longer so impossible?? There are new ways to go at the problem. But look a bit further into home listening.
The Future Force
Yes, ideally, compransion--compression/expansion--is a serious basis for the consumer dynamic range expander. But it is not the only basis. If I know the normal hi fi owner, there is another aspect and you can guess what it is-the sheer pleasure of a versatile new way to play around with your fi, to suit your taste and show off your equipment, and to heck with studious mirror images. You can build up your loud music even louder, cut back the soft parts to a smooth whisper, increase the total impact by a whole new order, and all without lifting a finger.
Nothing new in this sort of pleasure! After all, your choice of volume level has always been free and variable all over the spectrum, except for practicalities like neighbors. Some like it loud, some prefer the discreet (don't I know). Myself, I've learned to like it loud and you'd be amazed how often I am asked ... please turn it down. You think I'm just a musician? Same thing for tone controls; mostly we do with them what sounds good. And how about space expansion, reverb, Audio Pulse? All these are adjustable creatively to your choice and not necessarily according to any acoustic music original. So why not dynamic range expansion too? This is a legitimate way to use a clever automatic circuit and I see no reason to be doubtful about it, if that is your taste. A lot of people are going to like the newest expanders on just this basis, a single stage operation that enhances the signal for new creative effects. That, if you wish, is the musical wave of the future and a bigger factor in home hi-fi than most of us care to admit. I am all for it, with only one reservation: these sounds, these effects, are not for everyone.
For some of us, the two-stage expander remains a more important objective, factual compensation, as nearly as possible, for the alterations built into the musical signal. A flatter mirror is all we want. And decidedly, this is a tougher task, though I think it is the one dearest to the hearts of those who design and build expanders.
Music, acoustic music, the sound of music out of the original acoustic instrument, is still a major basis for audio reproduction and those of us who are concerned with this music are understandably leery of creative sonic extremes of any sort as the music comes forth in the home. We are not literal minded. No symphony in the home can ever sound like a symphony in the hall, nor should it. But, there must always be a relationship for us between these two extremes, one that allows us to hear the sense of our music freely "through" the audio medium with that ever-necessary illusion that it is there, right out in front of us.
To go back to my start, yes, we can do OK without dynamic range expansion, for the most part, because the altered audio product, such as it is, has been very cleverly tailored to fit the living room. And yet--? Can we do more? We always can.
No, we will never be able individually to match all those compressions with exact expansions, because we don't know which ones are there and how they work. That approach is hopeless. Not by a vast choice of different curves, either-a setting for every record company, broadcast network, disc cutting studio! That would be like the old equalizations for records, before standardization. Do I remember Old Columbia, New Columbia, NAB, RIAA, RCA, and dozen more choices; we were in Alphabet Smith's famous soup all over again. No, not that.
Computer Compransion Instead, I begin to see the way. By a modern statistical approach, maybe computer aided, of the sort we now do all the time. An expander circuit that operates--my first thought-like a Gallup Poll. Not a literal compensation for all those compressions, but a statistically derived correction, accurate plus-or-minus, almost a prediction, taking sophisticated computer account of a vast amount of known data-we do know the possible compressions. An expander circuit that would turn out to be right within acceptable limits, with only a few careful controls. Phew! One falls into jargon in these things. But this is how it could be done, and maybe has been done.
We have the two essentials. First the computer-type design techniques, the sort that have made incredible strides in the last decade. We can turn out "blueprints" of a predictable accuracy unthinkable a few years ago in the handwork, hit-or-miss, and intuition/guess era. Or worse, the systematic try-everything era. Multiply the old slow calculations by a thousandfold and you have what we have.
Tools for design. Second, we can build the circuitry to match, also maybe a thousand times more sophisticated, yet practical for home equipment.
Solid state, ICs, and all the rest.
So I am convinced, brainwise, that we CAN produce and probably HAVE produced a dynamic range expander to satisfy all of us, even including me.
And all the music lovers. It figures. It has to be! All I have to do now is to hear it.
(Source: Audio magazine, Jan. 1978, Edward Tatnall Canby)
=========
Vintage magazine ADs, Jan. 1978:
Model AT-15Sa/H Dual Magnet Stereo Cartridge pre-mounted in Universal tone arm head shell.
To find out how much better our cartridge sounds, play their demonstration record!
There are some very good test and demonstration records available. Some are designed to show off the capabilities of better-than-average cartridges... and reveal the weaknesses of inferior models.
We love them all.
Because the tougher the record, the better our Dual Magnet cartridges perform. Bring on the most stringent test record you can find. Or a demanding direct-to-disc recording if you will. Choose the Audio-Technica cartridge that meets your cost and performance objectives. Then listen.
Find out for yourself that when it comes to a duel between our cartridge and theirs...we're ready.
Even when they choose the weapons! What you'll hear is the best kind of proof that our Dual Magnet design and uncompromising craftsmanship is one of the most attractive values in high fidelity.
For their records...and yours!
audio-technica.
INNOVATION - PRECISION - INTEGRITY AUDIO-TECHNICA U.S., INC.
Dept. 18A , 33 Shiawassee Avenue, Fairlawn, Ohio 44313, USA.
Canada: Superior Electronics, Inc.
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Harman Kardon's ultrawideband 430 and 730 receivers.
Frequency response: 4-140,000 Hz.
Amplifier design: true Twin Power.
Two features you won't find in any other receiver except our own limited-production Citation.
Two features you won't find even in separate components-at anything less than twice the price.
They're there for just one simple reason.
The sound.
In sonic terms, ultrawideband components deliver two important benefits. Phase linearity and outstanding transient response.
Outstanding transient response is the ability of a component to respond instantly to the onset of a sound. It keeps the reproduced music as open and clear as the original.
Phase linearity describes a component's ability to pass multiple frequencies without changing their time relationships. It gives you a sound that stays open and accurate, clear on down to the bottom, Harman Kardon feels so strongly about these benefits that, in a market full of narrowband components, with frequency response from 20 to 20,000 Hz, we make only ultrawideband components.
The twin power supplies give you a further benefit. When the music makes extreme dynamic demands on one channel, the other channel simply cannot be affected-so even the loudest passages remain clear and open. That's why you'll find this feature in the world's finest high fidelity components.
Among which, of course, the Harman Kardon 430 and 730 receivers have been enthusiastically accepted.
harman/kardon
--wide, open sound--
Most people think only expensive separates can give you wideband response and twin power supplies.
Except for these two receivers, they're right.
Harman Kardon, 55 Ames Court, Plainview, New York 11803, USA.
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Crown
IOC
The different distortion indicator.
The Input-Output Comparator (IOC) now available on Crown D-150A and DC-300A amplifiers is a significant departure from traditional clipping indicators. The IOC reports all types of overload distortion by telling the user that the output waveform no longer matches the input waveform.
The IOC is so sensitive that distortion is reported before it is audible.
In the feedback system used in Crown amplifiers, the input IC is continually comparing input and output waveforms. If there is a difference, indicating a non-linearity in the amplifier, the input IC generates a correction signal.
If the output is distorted from some cause other than overload (for example, crossover distortion) the correction signal will bring the output waveform into compliance with the input.
Overload distortion, however, results from some circuit component operating beyond its linear range.
The correction signal cannot change the characteristics of the component, so the input IC continues to generate a large correction signal. This will happen regardless of the kind of overload-clipping, TIM or protection circuit activation.
The IOC was designed by Crown engineers to take advantage of this behavior, and to use it to report significant information about distortion to the user of the amp. The Crown IOC analyzes the correction signal and reports the existence of nonlinearities in the output waveform through a front-panel LED. The IOC is highly sensitive and detects distortion that is a great deal less than the .05% THD and IMD ratings of the D-150A and DC-300A. The user is thus notified about distortion before it is audible. The user also knows that the Crown IOC is reporting distortion of a music waveform, not just a laboratory test signal. Maximum useable gain for the D-150A or DC-300A can be determined by adjusting gain so the front panel LED's stay off, or come on briefly during the highest music peaks.
The IOC is available on all Crown DC-300A and D-150A amps manufactured after October, 1977.
Because of its value to any serious music listener, a factory retrofit is available for earlier units.
See your dealer soon for complete information about detecting distortion differently...with Crown.
crown. 1718 W. Mishawaka Rd., Elkhart, IN 46514, USA.
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FISHER
IF YOU HAVE AN EAR FOR MUSIC, YOU NEED THREE HEADS TO TAPE IT.
2-Head Cassette Recorders made home recording convenient.
Now the 3-Head Fisher CR5120 makes it professional.
It really isn't fair to compare the Fisher Studio Standard CR5120 to other cassette recorders. Its superior flexibility and performance are comparable only to the most sophisticated reel-to-reel tape decks.
The CR5120 combines the convenience of cassette with 3-head tape/source monitoring. The CR5120 delivers exceptional performance with important recording features like Dolby* noise reduction, signal limiting, and LED peak indicators.
Eliminate Guesswork. The only way to make consistently perfect high fidelity recordings is to compare the quality of the taped signal to the original while the tape is actually being made. Studio engineers call this "monitoring," and it can only be accomplished on a 3-head tape deck.
Monitoring subjects every inch of tape to instantaneous analysis by the most sensitive acoustic device available-the human ear-assuring a perfect "take" without guesswork.
Better Sound. Nearly all cassette decks have two tape heads-an erase head and a record/playback head. Even the best of them exhibit certain unavoidable compromises due to the combination record/playback head configuration.
These compromises, although accepted by the industry, were not acceptable to Fisher engineers. They created the CR5120, a major advancement in cassette deck technology utilizing three separate, precision long-life ferrite tape heads: erase, record, and playback.
Fisher engineers developed a wide-gap 4-micron record head for high output with an incredible 64dB signal-to-noise ratio...and a playback head having a very narrow gap (1.6 micron) for extended frequency response: 30 to 18,000 Hz, -± 3dB. The result is sound recorded on the CR5120 is exactly like the original. No more...and no less.
A recording studio engineer would never consider recording without the improved performance and monitoring capabilities of a 3-head tape deck-and neither should you.
The CR5120 provides a tape/source monitor switch for instantaneous comparison while listening.
2-Motor, Dual-Capstan Tape Transport.
Professional recording requires tape alignment exactly perpendicular to the tape heads. To accomplish this, Fisher engineers equipped the CR5120 with two capstan/pinch roller assemblies: one preceding, the other following the tape heads. Both capstans are micro-ground for absolute concentricity; and each is fitted with a heavy, dynamically balanced flywheel for smooth operation. The capstans are driven by a servo-controlled Hall-effect DC motor for absolute speed accuracy, independent of fluctuations in AC line voltage. A second, DC-controlled motor provides the proper hold-back tension. This configuration, standard for professional recording equipment, is responsible for the CR5120's exceptionally low wow and flutter specification of 0.04% WRMS ... performance superior to most reel-to-reel decks.
Dual Dolby Noise Reduction For Tape and FM. The CR5120 utilizes Dolby noise reduction to suppress tape hiss, improving recorded dynamic range up to 10dB. It incorporates separate record and playback Dolby IC circuitry so Na that both the source and monitored signals are simultaneously Dolby processed-a feature found only in the most advanced recording systems. Dolby circuitry is also provided to decode Dolby FM broadcasts.
Other Professional Features. Separate input and output controls for each channel provide maximum flexibility. Two illuminated VU meters, each with an LED peak indicator calibrated to +3 VU for accurate visual monitoring.
Switchable limiter circuitry prevents distortion due to tape saturation. A three digit counter with memory is included to quickly, automatically, locate the start of a recorded program.
The Final Word. The unique Fisher CR5120 is priced about $400*.
Available at fine audio stores or the audio department of better department stores.
FISHER--The first name in high fidelity. 1977, Fisher Corporation, Chatsworth, Calif. 91311, USA. Dolby is a trademark of Dolby Labs. Inc.
*suggested retail price. Actual sale price is determined by dealer.
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ALLISON ACOUSTICS
Used loudspeakers
Every Allison speaker system you buy as new has actually been "used" for 20 minutes to a half hour. Spending this much time on our test program gives us the confidence to publish a most complete set of specifications for our products, and to provide a full warranty that every one will meet those specifications within ±2 dB for at least five years.
To that end, we manufacture all our drivers and crossover networks ourselves. (Most of our competitors do not.) We test every driver and every crossover board (not just a random sample) to a set of close-tolerance standards. Only those that meet the standards are installed in cabinets.
Then every completed system must pass another long series of performance tests, before the cabinet gets its final coat of oil finish, a careful visual inspection, and is packed for shipment.
We don't have to guess what's inside our shipping cartons. We know. If you too would like to know, we'll be glad to send you our free 10-page catalog on request. It includes complete specifications and a statement of Full Warranty for Five Years.
ALLISON ACOUSTICS, 7 Tech Circle, Natick, Massachusetts 01760, USA.
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Luxman
As you would expect from LLX, our new R-1050 tuner/amplifier "is no mere run-of-the-mill receiver."
When LUX Audio entered the U.S. audio scene in 1975, we brought with us a worldwide reputation for excellence. But since vie also brought only our separate amplifiers and tuners, relatively few audiophiles could enjoy the special qualities of LUX performance.
Now, everyone who would like a LUX tuner, preamplifier and power amplifier-on a single chassis-can have them just that way.
We choose to call these new models "tuner/ amplifiers," although you probably think of them as "receivers." What's more important is how Hirsch-Houck Labs described the R-1050 in Stereo Review: "Given its features, appearance and performance, this is no mere run-of-the-mill receiver.... The excellent audio-distortion ratings ...obviously place it among the cleanest of the currently available receivers...every aspect of the receiver's operation and handling was as smooth and bug-free as its fine appearance would suggest."
Typical of the circuitry and features that result in such fine performance are these: a dual-gate MOSFET front end for high sensitivity, and a special linear-phase filter array for high selectivity, low distortion and twice stereo separation. The preamplifier section f-as a two-stage direct-coupled amp for accurate RIAA equalization and a good phono overload capability. And the power amplifier is direct coupled DC, in a true complementary symmetry configuration, for excellent transient and phase response.
Operating features include a six-LED peak level indicator for each channel; tape-to-tape dubbing with simultaneous listening to other program sources; turn-on time delay speaker protection plus automatic overload shutdown.
The sound of the R-1050 has been appreciated as much in England as here. For example, the British magazine HiFi at Home said: "...treble quality was light and delicate, something LUX engineers always seem to achieve ... bass output seemed plentiful and strong, as is often the case with enormous, low impedance power supplies."
If we've encouraged you to experience the sound of a LUX tuner/amplifier, your next step is to visit one of our carefully selected dealers.
We'll be pleased to send you the names of those in your area.
Luxman R-1050: 55 watts per channel. THD 0.05%. Suggested price.
$595. Other Luxman tuner-amplifiers: R-1040. 40 watts per channel.
THD 0.05%. Suggested price, $445. R-1120, 120 watts per channel.
THD 0.03%. Suggested price, $895. (Power ratings are minimum continuous output per channel, with both channels driven simultaneously into 8 ohm loads, from 20 to 20.000 Hz, and no more than quoted total harmonic distortion.) LUX Audio of America, Ltd.
160 Dupont Street. Plainview. New York 11803
------------------------------
WIN IT ALL!
The Accuphase Super System. An audio perfectionist's fantasy.
Here's how you can enter:
Visit a participating Accuphase dealer. Pick up an official entry blank, fill it in, mail it in, and hope. That's it-not a thing to buy For the nearest Accuphase dealer call toll-free, 24-hours a day 800-243-6000 (In Connecticut 1-800-882-6500).
Accuphase makes the extravagantly engineered, extravagantly praised components that Stereo Review calls "analogous to...Rolls Royce." By no coincidence at all, they're at the heart of this super stereo set-up.
And the other top-quality elements of our Super System are worthy teammates.
When you visit your dealer, listen to Accuphase. And listen to your dealer, too. He is a knowledgeable audio specialist; he features and recommends Accuphase. The two facts go together.
So hear Accuphase. Enter our winner-take-all Accuphase sweepstakes. And you may win all the deluxe audio equipment on this page.
How does that sound?
The Accuphase Super System
Accuphase P-300 Power Amplifier Accuphase C-200 Preamplifier-Control Center Accuphase T-100 FM Stereo-AM Tuner TEAC A-7300 Open-Reel Tape Deck TEAC 860 Cassette Deck Loudspeakers: 2 Infinity Quantum 2 and 2 Visonic D-80 Micro Seiki DDX-1000 Turntable Tone Arms: Micro Seiki MA-505, Infinity "Black Widow," and Audio Technica AT-1009 Phono Cartridges: Sonus Blue Label, Audio Technica AT-20 SLA, and Ortophon MC-20 Moving Coil (with MCA-76 Preamplifier) Soundcraftsmen RM-2212 Equalizer Audio Pulse Model One Digital Delay dbx 3BX Range Expander Micro Seiki MX-1 Headphones 2 TEAC ME-120 Microphones 2 TEAC Remote Control Units TEAC Cable Kit TEAC Dust Cover. TEAC Recorder Maintenance Kit TEAC Demagnetizer Discwasher System and Discwasher Zerostat Ion Generator Ampex Grand Master 10 1/2" Open-Reel Recording Tapes and 20/20 + Cassettes-1 carton 1 each Direct-To-Disc Albums: The catalogs of Sheffield, Umbrella, and Crystal Clear And best of all, an Accuphase T-shirt and halter!
Accuphase--When you're really serious about your music.
Official Rules
1. To enter, complete the official entry form available from a participating Accuphase dealer.
2, All entries must be postmarked by January 31, 1978, and received by February 28, 1978.
3. Winner will be selected in a random drawing. Result of the drawing will be final. Winner will be notified by mail. Odds of winning will be determined by number of entries received. Only one prize sound system will be awarded. State, federal, and other taxes imposed on the prize-winner will be the sole responsibility of the prize-winner.
4. Employees of TEAC Corporation of America (distributor of Accuphase), affiliated companies, and sales agents, and the families of any such employees are not eligible. Void where prohibited or restricted by law.
5. Any request for the name of the winner should be mailed after February 28, 1978, to: Accuphase Super System TEAC Corporation of America 7733 Telegraph Road Montebello, California 90640
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OPTONICA
The Optimum
The first tuner and amplifier that won't scare you into buying a receiver.
Most people buy a receiver instead of a separate tuner and amplifier because they think it's easier to handle, less complicated, not as frightening, even less expensive.
Nothing could be further from the truth. Which is amply proven by the Optonica ST-3636 tuner and the SM-4646 amplifier. a pair so easy to get along with.
and so affordable.
Nobody gives you a combination of features like the smart-looking Optonica' ST-3636 tuner. It's got Opto-Lock tuning, which locks in the signal and locks out station drift and unwanted noise. The advanced FM front end is designed for excellent sensitivity, outstanding selectivity and a high signal-to-noise ratio.
The Optonica ST-3636 also comes with air check circuitry so that a tape deck can be calibrated to record FM broadcasts at the optimum level.
Just wait until you get your hands on Optonica's SM-4646 amplifier. The beautifully engineered front panel gives you total control flexibility to meet every recording and listening need.
There are three independent power supply circuits to give you full range stability and power handling. This Delta power amplifier puts out smooth. effortless reproduction.
With the SM-4646 you've got the power to handle it all. There's a full 85 watts per channel minimum RMS at 8 ohms, from 20 Hz to 20 kHz with no more than 0.08% THD. With that kind of power, you need protection. And you get it with an LED Automatic Protection Circuit. This exclusive Optonica feature isolates vital output components if the outputs are accidentally shorted. And to prevent speaker damage, the circuit will also activate if excessive DC voltage occurs at the output.
We invite you to test the Optimum tuner and amplifier to find out just how comfortable separates can be for you.
We'd also like to give you a free copy of our full line catalog. Just call toll-free 800-447-4700 day or night (in Illinois dial 800-322-4400) for the name and address of your nearest Optonica showroom, or write Optonica. Dept. AU, IO Keystone Place, Paramus. Nev. Jersey 07652.
THE OPTIMUM. OPTONICA
------------------------
BIC VENTURI.
Tomorrow's technology in 7 Formulas today.
This year, with the addition of new Formula 3 and 6 models, we've closed the gaps in our line. The seven BI C VENTURI Formulas are shown here in ascending order.
Formulas 1 through 4 offer a choice between two-way and three-way systems of different performance capabilities. While models 5 to 7 add the system monitor technology to speakers of increasing size and sophistication.
Thus, whatever level of refinement a music system has reached, there's a BIC VENTURI Formula that can upgrade its performance. And together they offer a range of choice (and price) that is unique in the industry.
For literature, and complete technical details, write us at the address below.
Speaker design is a funny business.
It is relatively easy to be esoteric. Much harder (and rarer) to be truly advanced.
Nonetheless, in 1973, BIC set out to make some fundamental improvements in speaker system design.
We developed, and patented, the BIC VENTURI coupled path to multiply bass energy and the BICONEX horn to match that new response.
The result was a quantum leap forward in loudspeaker efficiency that dispatched changes throughout the industry.
Last year, we introduced a new concept in speakers. The System Monitor Speaker, with electronic circuitry that takes measurements, displays information, even initiates action.
That gave loudspeakers the unique ability to make the rest of a component system perform better. In our view, a landmark development.
In just four years, BIC advancements had twice marked the path for future speaker evolvement. And, quite by design, all this was managed within a line of speakers most enthusiasts can realistically afford.
BIC VENTURI SPEAKER SYSTEMS--TOMORROW'S TECHNOLOGY TODAY
BIC VENTURI, Westbury, N.Y. 11590. BIC, BICVENTURI and BICONEX are trademarks of British Industries Co. Division of Avnet, Inc.
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KOSS
Introducing the Koss Theory of loudspeaker design and the three new Koss CM speaker systems that prove it.
When Koss invented the stereophone, music lovers and audio experts were amazed at the low distortion, broadband frequency response, and high efficiency achieved by the Koss drivers. Indeed, the resultant Sound of Koss created a revolution in the audio industry.
Today, the exciting new Koss Theory of loudspeaker design has created another revolution.
By developing a complex series of audio engineering formulas and by utilizing the precise knowledge of modern computer science, Koss engineers have created a breakthrough in loudspeaker technology of such significance that it heralds the second major revolution in loudspeaker design technology.
For the first time, it's now possible to scientifically derive and produce the optimum system parameters for any loudspeaker.
By computerizing the Koss Theory and by first selecting the number of band passes desired in the system, the system's desired efficiency, the f3, low bass cutoff, and the desired cabinet size; Koss engineers are able to derive specific design parameters for every component in the total system. In fact, the Koss Theory is so sophisticated that even the structural design of the cabinet and the precise positioning of the components in the cabinet for optimum dispersion and phase coherency are specified.
Of course, what's really important is not the Koss Theory itself but the sound of the three new Koss speakers that prove it. Indeed, with current technology, there are no speakers available at similar prices that can match the Koss CM 1010 two bandpass loudspeaker, the Koss CM 1020 three bandpass loudspeaker or the Koss CM 1030 four bandpass loudspeaker in low distortion, high efficiency, and broadband frequency response.
But then, the incredible sound of these three new speakers isn't surprising when you consider some of the revolutionary new features they offer: Take for example, the CM 1010's unique mass aligned 10-inch passive radiator that enhances the lower 2 octaves of the bass and allows for the use of a specially designed 8-inch woofer to reproduce the critical midrange up to 2.5 kHz. With the alignment mass in place, the CM 1010 reproduces a maximally flat response from an f3 of 35 Hz on outward. However, by removing the alignment mass, those who prefer more acoustic energy in the 50 to 80 Hz range can create an f3 of 40 Hz and a low bass ripple of 1% dB centering on 60 Hz.
Or take the CM 1020's dual port design that provides an optimal cross sectional port area for proper cabinet tuning. Or the unique parallel midrange design of the CM 1030. By utilizing two 4 1/2-inch drivers operating in parallel, Koss engineers were able to decrease the excursion of each driver thus creating a dramatic decrease in potential driver distortion and an equally exciting increase in the overall brilliance and presence of the midrange response. Then again there's the Koss high bandpass 1-inch dome tweeter and unique acoustic transformer that creates an incredible 6 dB increase in headroom.
And, of course, there's also the patented quasi second-order crossover network that provides a smooth, acoustically invisible transition from bandpass to bandpass.
But those are just some of the revolutionary features offered by the new Koss CM loudspeakers.
Why not prove the Koss Theory of loudspeaker design to yourself by asking your Audio Dealer to give you a full demonstration of the beautiful Sound of Koss. Or write to Fred Forbes, c/o the Koss Corporation, for our free, full color CM loudspeaker brochure. Once you've heard these revolutionary new loudspeakers, we think you'll agree: hearing is believing.
KOSS CM SPEAKER SYSTEMS hearing is believing.
KOSS CORPORATION, 4129 N Port Washington Ave., Milwaukee, Wisconsin 53212, USA.
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Kenwood
ONE GOOD THING LEADS TO ANOTHER.
When it comes to a super-powered receiver, people know a good thing when they hear it.
That's why our KR-9600 is one of the most popular receivers in its category.
For less than $750* you get 160 watts per channel, minimum RMS at 8 ohms, from 20-20,000 Hz with no more than 0.08% total harmonic distortion. With all the features and performance you'd expect from our top of the line receiver.
But let's face it. A lot of people don't need all that power. That's why we developed the KR-4070. It's got 40 watts per channel, minimum RMS at 8 ohms, from 20-20,000 Hz, with no more than 0.1% total harmonic distortion. (That's correct, 0.1% TH D.) Plus all the features most people need.
But what's incredible, is that you can buy it for less than $300'.` Depending on how much power you need, either receiver will give you more performance for less money than you thought possible.
Because at Kenwood, we think you can't get too much of a good thing.
Nationally advertised value. Actual prices are established by Kenwood dealers.
Handles optional.
KENWOOD. For the Kenwood Dealer nearest you, see your Yellow Pages, or write Kenwood, 15777 S. Broadway, Gardena, CA 90248
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Radio Shack
The Realistic 2000
Proof that you don't have to pay a fortune for a first-class, high-power stereo amplifier What more proof do you need than rave reviews by a major audio magazine? Stereo Review (April 1977) says "The SA-2000 can deliver as much power, with as little distortion, as will ever be required by the vast majority of its users: 55 watts per channel, minimum RMS at 8 ohms from 20-20,000 Hz, with no more than 0.3% total harmonic distortion. Our tone controls "are among the better ones we have seen” says Stereo Review. They give you a choice, by boosting or cutting bass at 125 or 400 Hz and treble at 3 kHz or 7 kHz. It's almost like having four separate tone controls. Stereo Review also says ours is "one of the very few loudness compensation systems that really works:' That's because exclusive Perfect Lever makes our Perfect Loudness*' system adjustable to any listening level so that the "boominess" so often heard with ordinary loudness systems is eliminated. Among many other features, the SA-2000 has two magnetic phono inputs, dubbing and monitoring circuits for two tape decks, and a walnut veneer case. Only $269.95* even less if you buy it in a complete system.
These two credit cards honored at most Radio Shacks.
SOLD ONLY WHERE YOU SEE THIS SIGN:
A DIVISION OF TANDY CORPORATION FORT WORTH, TEXAS 76102 OVER 6000 LOCATIONS IN NINE COUNTRIES
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The Acoustat X full-range direct-drive electrostatic speaker system.
Each speaker contains its own SERVO-CHARGE power amplifier with direct high voltage, high impedance drive ideally matched to the demanding requirements of an electrostatic transducer.
The critically acclaimed ACOUSTAT X provides phenomenally detailed sound with superb definition. It does this with a remarkable dynamic range (105 dB in typical rooms) and spectacular bass response (flat to 30 Hz) that seems incredible coming from a pure electrostatic device. They are highly accurate and highly musical speakers with truly startling transient response. We predict you will hear things in your reference recordings you never dreamed were there. In addition the ACOUSTAT X will recreate the sense of "being there" to a degree unequalled by any other speaker system regardless of price.
But aren't electrostatic speakers notoriously unreliable? Others may be, but not the ACOUSTAT X's direct drive design. In nearly two years of production with nationwide and worldwide distribution we have yet to see our first "in use" panel failure.
The price? About the same as high quality cone systems with power amplifiers.
Write for complete information.
Acoustat Corporation 4020 North 29 Ave Hollywood. Fla. 33020
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Signet
Introducing the phono cartridge that will never come out of the lab.
Each Signet cartridge is hand-made in the laboratory of one of the world's largest phono cartridge manufacturers. By producing Signet in the lab, each unit gets unique personal attention, free from the pressures of volume production.
The Signet group can fully concentrate on the nuances of performance. They can experiment directly with new materials and technology. For instance, stylus cantilevers are now available in your choice of tapered-tube aluminum alloy (standard), beryllium, titanium, or even carbon fiber. And diamonds much too small for normal mass production techniques are used to reduce moving mass.
Signet is intended solely for the audio enthusiast who is both knowledgeable and critical. And available only from the handful of dealers who understand your needs. Write today for literature and dealer list.
Dual Magnets. Stereo Phono Cartridges with Micro-Mass Moving System.
A product of Signet Division, Audio-Technica U.S., Inc., 33 Shiawassee Avenue, Dept. 18A, Fairlawn, Ohio 44313, USA.
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Marantz
Ultimately It's Marantz--Go For It.
Marantz goes beyond THD to lower TIM (transient intermodulation distortion).
Because TIM doesn't show up on conventional amplifier testing equipment, most manufacturers and their engineers aren't even aware that it exists in their amplifiers. Even if they were, they probably wouldn't know what to do about it.
But because Marantz builds for the music and not just the specs we know how destructive TIM can be to pure sound reproduction.
And we've developed a revolutionary new circuit design to eliminate it.
The reduction of TIM can be the single most important element in making an amplifier sound better. For instance, two amplifiers with identical total harmonic distortion (THD) specifications should sound the same when compared ... but the one with low TIM will sound audibly better! That's because TIM adds an unnatural harshness to the music. It's not only detrimental to pure sound reproduction, but it can have an emotional effect that you experience as "listening fatigue:'
TIM is caused by an improper design of "negative feedback circuitry;' by other manufacturers.
Every modern amplifier uses it to lower THD. But excessive negative feedback coupled with an insufficient slew rate' can lead to gross internal overloads under the constantly changing transient and sound levels of music.
That distortion is TIM. The gentle slopes of continuous sine wave test signals normally used to test an amplifier simply cannot detect TIM distortion. It requires the type of extremely sophisticated spectrum analysis equipment developed by the space industry to analyze radio frequencies.
Our answer to TIM is a circuit design that ensures the widest bandwidth and the lowest obtainable THD before negative feedback is applied. The Marantz 170DC Stereo Power Amplifier (the 1152DC, 1180DC and 1122DC also use this circuitry), for instance, needs only 1/100th (-40 dB) the amount of negative feedback commonly required by other amplifiers to yield the same low total harmonic distortion figures.
Incredibly, Marantz amplifiers with low TIM design can deliver flat frequency response from 0 Hz to 20 kHz without the use of negative feedback. And this same circuit design provides the optimum slew rate for minimum TIM and maximum reliability.
Result: Marantz reduces TIM to an inaudible level, which means you get clear, clean sound from all your records and tapes. Think of Marantz with low TIM as a window to the original performance.
If you truly want the best reproduction of musical sound available anywhere-and , are willing to spend a little more to get it-then go for it.
Go for Marantz.
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Spectral analysis demonstrates that Marantz conquers TIM distortion.
Test signal (sine and square waves mixed).
Competitive amplifier's output. Note the added distortion products.
Marantz 1180 DC's output is identical to the input test signal.
marantz -- We sound better.
*The maximum change of voltage per unit time. 1978 Marantz Co., Inc., a subsidiary of Superscope, Inc., 20525 Nordhoff St., Chatsworth, CA 91311. Prices and models subject to change without notice. Your Marantz dealer has the full line of Marantz amplifiers.
Look for him in the Yellow Pages.
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TEAC
There are certain other instruments every serious musician should know how to play.
The implements used in every art form except music both create and preserve the art. If music isn't captured at the time it's created, it's gone forever.
But the instruments used to capture music can also be used to alter, refine and improve it.
Instruments like the A-2340SX and A-33405 4-channel tape recorders with Simul-Sync for multitrack recording and over-dubbing, as well as mastering decks like the A-6100 and A-3300SX-2T for mixing down multichannel tapes to stereo.
Instruments like the Model 2A Mixing Console with an MB-20 Meter Bridge for control of volume, tone, blend and spatial positioning. There are also microphones for every recording need along with accessories like the PB-64 Patch Bay and cables to help organize the process.
TEAC is the leader in multitrack. Less than a decade after multitrack equipment was introduced to the professional industry, TEAC introduced it to people serious about their music. Today, thousands of musicians and recordists are getting many of the important elements of the studio experience but without the studio bill. And TEAC continues its commitment to multitrack excellence.
To find out more about the adventure of multitrack recording and to hear the quality of music that can be made on TEAC multitrack equipment, send $2 to Dept. 30 for our "Home Made With TEAC" Album. Or, if you can't wait to get your hands on the instruments every musician should know how to play, see your TEAC dealer now. TEAC First. Because they last. TEAC, 1977
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