Audioclinic
Joseph Giovanelli
Cartridge Output and Stylus Velocity
Q. In the "Equipment Directory" in the October, 1975 issue of Audio Magazine, there is one set of specifications that is confusing.
The amplifier section of the directory refers to and measures phono sensitivity in mV. The phono cartridge section refers to and measures output in mV at a velocity of 5 cm/sec. The specifications supplied by the manufacturers, however, do not in all cases state output in terms of this 5 cm/sec. figure. The Empire cartridges refer to a velocity of 3.53 cm/sec. The Pickerings refer to a velocity of 5.5 cm/sec. with brush.
Since a cartridge must be selected whose rated output exceeds the phono sensitivity of the amplifier being used with it, how does one match the two when there is no common reference?
-L.L., Kew Gardens, N. Y.
A. The voltage output of a cartridge and the velocity of a stylus follow one another in direct proportion. Doubling the velocity of the stylus will increase the voltage output of the cartridge to twice its original value. Thus, if you have a cartridge which produces 2 mV at 2.5 cm/sec. and you want to know what the cartridge will produce at 5 cm/sec., you can figure from the above that this cartridge will produce 4 mV at 5 cm/sec. That is all there is to this sort of problem.
Select a cartridge which does not exceed the minimum sensitivity of the preamplifier section of your equipment by more than about 6 dB as this precaution will prevent overloading the input circuitry. You can use a cartridge having higher output than this if you know the maximum signal level which can be handled without causing overload and watch your gain setting.
Ceramic and Magnetic Cartridges
Q. I have read the statement that a magnetic cartridge is better than a ceramic one. Why? Instead of the ceramic cartridge which is supposed to be used with my receiver, would it hurt the receiver in any way if I were to use a magnetic cartridge?
-Jim Pykonen, St. Clair Shores, Mich.
A. Both ceramic and magnetic cartridges produce a signal because their styli are moved by the groove on the record, however, the method used to produce the electrical signal is different. With the ceramic cartridge, the stylus does a considerable amount of mechanical work in flexing a small piece of "ceramic" material, usually barium titanate, which produces a relatively large voltage between the two sides of the element. In the magnetic cartridge, the signal voltage is produced because small magnets, attached to the back end of the stylus, are moved close to the coils attached to the main body of the cartridge, inducing the voltage. A great deal less work is necessary with this method.
While the magnetic cartridge produces a smaller signal voltage than the ceramic type, the magnetic cartridge will track difficult grooves properly at much lower tracking forces, resulting in considerably reduced record wear.
One advantage of the ceramic type is that the signal voltage it produces is easy to equalize to the curve used in recording, while the magnetic type requires more sophisticated circuitry for this. The ceramic type, however, almost always has some resonant peaks in its response and these peaks are difficult to remove with an economical circuit. The result is that the magnetic type, after equalization, has the flattest response.
It is for all these reasons that the magnetic type is considered superior.
While you will not hurt your receiver if you simply exchange the ceramic cartridge for a magnetic type, you will probably hear no sound (or at best a treble-heavy sound) when in phono mode as the receiver is set up for the higher signal voltages produced by the ceramic cartridge. If you wish to go to the magnetic type, you should purchase one of the preamplifiers made specially for such changes. They go between the turntable/cartridge and the receiver and boost the cartridge's signal to the proper level, as well as providing the necessary equalization for the magnetic cartridge.
Homemade Wind Screens
A few of my microphones have no wind screens. I improvised and discovered that the foam used in air conditioning filters works well if you use two or three layers of the material and fasten it to the microphone with a hose clamp. Although this arrangement is unsightly, it works well.
Richard D. Taubold, Urbana, Ill.
About The Cover: "Gee, Dad, it's a Wurlitzerl" The nostalgia trend has given a second life to the artifacts of our recent past. This whirling-colored, big-voiced 1947 Wurlitzer jukebox now delights bicentennial visitors to the Paper Moon, an old time newsstand and cafe on trendy South Street in Old Philadelphia. And how's this for nostalgia, you get six plays for a quarter! Most popular selection? Rum and Coca Cola by the Andrews Sisters.
================
Tape Guide
by Herman Burstein
Taping Discs Revisited
In the September, 1975, "Tape Guide" column Mr. Ted E. Hayen asked about the difference in recording levels of about 4-to-5 dB between channels on records of different manufacturers. In his answer, Mr. Burstein covers the fact that there are sometimes variations in recordings between right and left channels. He also states that there might be an error in the calibration of the VU meters of the tape recorder used. He recommended that Mr. Hayen adjust recording level on the records he is trying to record, making the assumption that the VU meters are identically calibrated. Unfortunately, he did not give Mr. Hayen a method via which to check the calibration of his meters and record level controls.
In order to calibrate the entire system (or to check calibration of the entire system, including record level controls and VU meters), all that Mr. Hayen has to do is to play a monaural record with all the controls in his system in the stereo position. When a monaural record is played in this fashion, the same signal will appear at both record heads, and all one has to do is calibrate his record level controls so that the reading on both VU meters will be identical. If he now plays back a recording made in this fashion, and adjusts his playback controls (making the assumption that the VU meters work on playback and can be switched to read the signal coming from the tape), his entire system will be calibrated. In addition, if there are gross differences in the position of the record and/or playback level controls, he will know that there is something amiss and that part of his system requires adjustment or repair.
Indeed, this is the best way of adjusting any tape recorder in which you have both a master gain control and separate level controls for each channel.
C. Victor Campos, Acoustic Research, Norwood, Mass.
Track Spacing
Q. I've read that different heads have varying distances between the tracks. Is this a problem?
-Ronald Slakie, Tacoma, Wash.
A. The same kind of head (for example, a quarter-track playback head) will have the same track spacing regardless of manufacturer-except for possible mistakes in manufacturing.
Track spacing is specified by NAB (National Association of Broadcasters) and to my knowledge is followed by all manufacturers, within permissible tolerances. However, there are differences in spacing as between quarter track and half-track heads. And there are slight differences for stereo heads, as between erase heads and those used for recording and/or playback.
These differences are to make sure that the erase head spans all the recorded track and slightly more.
Hiss Reduction
Q. I have a Concord tape deck which has been biased for Scotch low noise tape and is used only at 7.5 ips for music. However, there is a small amount of hiss. When recording material off TV I use cheap tape, operate at 3-3/4 ips, and turn the treble up to improve the treble response; yet I am amazed to find that there is less hiss than when using good tape at 7.5 ips.
Other than the fact that I record off TV at a slightly higher level, 1 am at a loss to explain why I get less noise in the latter mode.-Dennis Brandt, Emporium, Penna.
A. At 3-3/4 ips, high frequency response is appreciably less than at 7.5ips for some tape machines. Hence tape hiss-all other factors remaining constant-would tend to be less noticeable at 3-3/4 ips in the case of such machines. When you turn up the treble at 3-3/4 ips, you may not be turning it up enough to cancel out the hiss advantage. When using low-noise tape, the treble boost in recording is supposed to be reduced somewhat, and the recording level is supposed to be increased somewhat. In adjusting your tape deck for low-noise tape, only the bias may have been changed and not the record treble boost and recording level. Accordingly, you get more noise than if all the required adjustments were correctly made. On top of this, as you state, you record at a higher level from TV (at 3-3/4 ips)
than you do for music (at 7.5 ips). Finally, it may be that the nature of your hearing ability has something to do with the matter. When you turn up the treble at 3-3/4 ips, you may be satisfying your ears out to, say 10,000 Hz rather than to 20,000 Hz. If you can't hear much beyond 10,000 or 12,000 Hz, you may not be turning up the treble enough to increase hiss appreciably.
Stereo Playback
Q. I have a Lafayette transistorized 4-track mono open-reel tape machine with tape head outputs. I would like to incorporate a preamp/equalization circuit (transistorized) into the machine, thereby converting it into a stereo playback deck suitable for tape dubbing. I don't wish to consider any separate tape preamps as they have additional features I don't want and are awkward to carry around. There is also enough room to mount a circuit about the size of a drinking glass, and I'd enjoy building the circuit. How do I go about doing this?
-Joel Jevotovsky, Brooklyn, N.Y. A.
You might copy the playback electronics now in your tape machine, or obtain a transistorized playback circuit from Nortronics or other sources.
You might also refer to articles on tape preamps published in Audio and other periodicals in past years. You could also copy the playback circuitry of a high quality tape machine, or buy one of the tape playback preamps which you say you don't want to consider, dismantle it, then reassemble it inside your Lafayette machine. The cost of separate parts probably wouldn't be much less than buying the entire preamp. As to what you do once you have a desirable circuit or collection of parts before you is outside the scope of this column. Novices usually gain aptitude in this kind of thing through experience with kits or under the tutelage of a friend.
Recorder Comparison
Q. I have attempted to compare tape recorders on the basis of data appearing in Audio and other magazines. Most of the time one machine will look better in some categories and not in others. I would like to know how to analyze the data. Which categories are most important? How good would one deck have to be in lesser categories to make up for slight deficiencies in more important categories? Also, what is the smallest amount of difference in each specification that is worth considering in certain categories but not in others?
-Jerry Sheppard, Atlanta, Ga.
A. The answers to your questions are not easy, and a complete attempt would require several pages. Perhaps the following may help somewhat.
The most important requirements in the case of a tape recorder are flat and wide frequency response, high signal-to-noise ratio, low distortion, and low wow and flutter. A good quality machine would have response within ±1 to 11/2 dB between about 30 and 16,000 Hz, signal-to-noise ratio bordering or exceeding (particularly with Dolby-B) 60 dB, and under 0.1% wow and flutter. Distortion is inferred in the S/N specification, which is ordinarily based on a signal level resulting in 3% harmonic distortion at 400 Hz on the tape. In the case of specifications stated in dB, significant differences are on the order of about 1 to 2 dB. You might notice a difference between Machine A flat within 1 dB and Machine B flat within 2 dB. You would be likely to notice a difference between Machine A and Machine C flat within 3 dB. Similar parameters hold for S/N.
Dolby Dilemma
Q. I have several questions concerning the Dolby-B system. It is indicated that the gain of the system is controlled by the level of the input signal. This appears to be far from an optimum system as masking of noise occurs only if the desired signal has a strong component near the noise frequency. In the Dolby-B system, a signal in the bass would cause no compression of the signal, and one would be left with the full noise component which would be audible; there would be no masking due to the large frequency difference. Why is there only a 10 dB improvement in signal-to-noise ratio? I realize that large-signal amplifiers tend to distort, but why not lower the input signal to the Dolby by 10 dB, compress it 20 dB, and then amplify it again in a linear amplifier?
-Jeffrey AhI, Ithaca, N.Y.
A. Noise is most noticeable in the treble range. The principle of the Dolby-B system is to emphasize the treble when the signal level is low; because the level is low, such emphasis does not noticeably increase distortion in recording. In playback, when the signal is low, the treble range is correspondingly de-emphasized, thus restoring flat response and at the same time reducing noise (treble frequencies) that occur in recording and playback.
Why "only" 10 dB improvement in S/N? This is probably as much as is feasible in view of the problem of avoiding distortion due to treble emphasis in recording. Besides, 10 dB is quite an improvement; it can convert garden-variety 50 dB S/N into high quality 60 dB S/N.
=================
Dear Editor:
More on TV Audio
Dear Sir: I read with interest the letter from R. P. Markey in the April issue and felt that I might add something to his comments.
The problems with TV audio are primarily due to losses of quality through the AT&T long lines system and, at present, somewhat unavoidable. Be advised however that within two years the PBS (Public Broadcasting Service) stations throughout the United States will no longer be using the long lines system for distribution of network programming, going instead to a leased satellite system for both audio and video distribution.
The proposed specifications are as follows: Flat response from 15 Hz to 15 kHz, random noise (flat and new CMTT weighted) peak signal-to-noise ratio of better than 68 dB, distortion under 1?o throughout the audio range, and crosstalk down more than 70 dB. We can only hope that in the next few years AT&T will improve audio quality to the three commercial networks, or that perhaps the networks will follow Public Television's lead in striving for true hi-fi television audio.
Ralph Strader Engineering Supervisor, WNIT-TV PBS South Bend, Ind. 46624
Rack Mounting
Dear Sir:
One of the things that I have noted with delight is that a lot of hi-fi gear is once again available with rack mounts, as was the case 20 years ago.
Almost all of the moosey power amplifiers come that way, and the noise reducers, the graphic equalizers, and a new AM tuner are like that.
So why don't the manufacturers of most tape recorders make rack mounts? I wrote many of the companies asking for information pertaining thereto. Most of the companies I wrote sent me brochures that didn't say anything about rack mounts. A few do. The only cassette machine with rack mounts costs over $1000. Surely I am not the only person in "the biz" who specifies rack mounts in commercial installations and finds it convenient to have a recorder as part of a PA system. Radio stations in a town this size play news actualities and sometimes entire programs (ugh!) from cassettes, and they sometimes do that with battery portables, since no larger gear is very convenient. My home installation is rack mounted, and I'm convinced that the "ultimate" system-if there is one-has everything bolted down.
Audio magazine could certainly do a lot of folks a favor by prodding the manufacturers into making these things available, as they will listen to you more than to me. And if you can find me a rack-mounted cassette recorder-player for less than $500, I'll take two. And I can sell three others to clients in Ridgecrest (population 15,000).
James Rieger Engineer Kitchen Productions 205 S. Silver Ridge Dr. Ridgecrest, Ca. 93555
Dissident Critic
Dear Sir: I read my first issue ever (and possibly my last?) of Audio. Yes, your "systems" articles are good. But let me tell you, your Record & Tape Reviews suck eggs! Having decided on a journalistic career, I feel it necessary to set the facts straight. Your "writers" of the column are legends in their own minds.
Fleetwood Mac is a highly skilled Rock Group. Chris McVie's warm voice and exquisite talent contributes to this albums glowing stardom. Landslide happens to be a very hot song.
As for the "death of the progressive Fleetwood Mac", you couldn't be more wrong.
Now my second complaint. At this very moment, I am listening to an extremely talented artist. Dan Fogelberg proves once more, if you have the ability and talent (which he does) and the incentive, you can succeed (sic). He not only wrote the songs on the album, but he also played nearly all of the instruments on top of that, he does all of his cover artwork. Regarding your statement of Crosby & Nash being under-talented, I'm sorry to inform you, but this is also wrong.
They were part of a very successful group. Although the group was short-lived, they went on to put out two very fine Lp's.
As for these reviews:
Performance: F. I base my third conviction on the previously stated facts.
Captain Fantastic and the Brown Dirt Cowboy.
What can be said? Elton and Taupin have fallen from their lofty positions among the stars. Just because someone pumps out asinine albums, one after the other, does not mean they are successful. What it is, simply enough, is the fulfillment of a recording contract. You ask "How in 1976 does anybody review an E.J. record?" The answer is easy. Just as you would any other album...hopefully objectively. Just coz (sic) the guys have put out some top notch albums, that doesn't mean they're superstars. It takes alot (sic) to be a superstar, and "junk" albums aren't one of the qualifications.
I wouldn't be surprised if this isn't published. You have proven to me that your staff doesn't have enough balls to stray from the safety of their top 40 ideals.
M. J. Martis Monongahela, Pa.
Editor's Comment:
Thank you for your compliment on Audio's "systems" articles, and congratulations on your choice of journalism as a career field. Some things you should find helpful are: a good dictionary, a concise manual of grammar, some subscriptions to the rock journals, and some college courses in criticism.
Station Practice
Dear Sir: In response to your request in the January issue for broadcaster's comments regarding the audio quality of radio stations, I would agree with Mr. Swartzendruber's observation that AM transmitters and their associated audio equipment are capable of audio quality which exceeds that of virtually all of the present AM tuners and receivers. It is not uncommon to find even relatively old transmitter designs capable of frequency responses of ± 2 dB from 25 Hz to 12 kHz. And now with more sophisticated modulation techniques, such as pulse duration modulation and others, as well as increasing use of completely solid-state transmitters with d.c. coupled modulators, response of ±1 dB from 20 Hz to 15 kHz is not unusual. Also, square wave response of the latest designs is very good, and THD at 95% modulation is usually under 1% for all frequencies and somewhat less than 0.5% for mid band frequencies.
Unfortunately, this is not the kind of quality that many stations care to transmit. Many broadcasters choose to use the improved performance that results from the latest transmitter designs to increase the quantity (loudness) rather than the quality of their signals. But then, to many listeners, louder is better.
With FM transmitters, the situation is not quite the same as with AM. The current generation of FM exciters and stereo generators is still an order of magnitude or so below the quality of the very best state-of-the-art tuners.
However, the inherent bandwidth and other limitations that are a part of both AM and FM stereo transmission systems prevent them from being as transparent as the electronics in most hi-fi systems.
In many cases, the reason for the poor audio quality of AM and FM radio is not the audio quality of the transmitter or receiver, but rather the audio quality of the programming.
This quality depends upon how carefully the various assortment of turntables, tape machines, amplifiers, equalizers, filters, compressors, limiters, peak clippers, telephone lines, and station-to-transmitter microwave links that make up a radio station are used and maintained.
There are other factors affecting a station's air sound over which the broadcaster may not have much control. These would include the quality of the records (mostly 45s) that radio stations receive from the record companies and the quality-compromising problems related to the tape cartridges that have become so common in broadcasting. The somewhat less than state-of-the-ail performance of much of the audio equipment available from broadcast equipment manufacturers has led some more progressive-minded stations to use high quality audiophile equipment instead.
Also, the use of matrix quadraphonic encoders, the impending adoption of "discrete" quadraphonic FM, and the proposals for AM stereo don't help the situation.
Another factor affecting the audio quality heard on the radio is the widespread use (especially on FM) of automation equipment and prerecorded tapes to provide a station's programming. Often the equipment is not properly maintained or programmed and the tapes are of poor quality. Use of noise reduction equipment with tape machines, while standard practice in recording studios and very common with audiophiles, is virtually non-existent in broadcasting. Some stations receive their tapes from a programming service, and only a few of these companies have more than casual concern about the quality of their tapes. Since automation equipment can run for hours unattended, often it does. The listeners may actually know more about the station's programming and its quality than the station's personnel.
Certainly, there are many exceptions to all of this. But these are not the problem. The exceptional stations are still too few and far between.
What is needed, is more stations becoming concerned about the quality of their air sound and then taking the time and effort needed to improve it.
In addition, these stations will need the cooperation of the record companies, equipment manufacturers, programming services and the listeners as well. Listeners can help by simply providing feedback for the broadcaster in the form of constructive criticism, including specific suggestions, when possible. In fact, a visit to a local radio station can be a very enlightening experience for both the listener and the broadcaster.
Scott Pendergraft
Chief Engineer, Radio Statesboro Statesboro, Ga.
==============
Behind The Scenes
by Bert Whyte
THIS ISSUE of Audio will appear during the Consumer Electronic Show in Chicago, around the middle of June. Many people in the hi-fi industry are anxious to see how much activity in quadraphonic sound there will be at this show. It is no secret that for the past two years quadraphonic sound has been in trouble in the audio marketplace.
To get a perspective on this matter, I interviewed Mr. Jerry LeBow, who is vice-president of Frank Barth Inc., New York, which handles the advertising for Sansui. Sansui is, of course, the Japanese company that invented the QS quadraphonic sound process. Mr. LeBow has been actively involved with all aspects of QS promotion and marketing and has demonstrated QS sound to many engineers in the audio, recording company, and broadcast fields. He is generally regarded as one of the most articulate spokesmen for quadraphonic sound, and in this interview, we herewith present his views on the current low estate of this medium.
B: Jerry, it would seem that certain segments of the audio press are determined to kill off quadraphonic sound, as evidenced by expressions in articles on the subject, such as "four-channel is dead," "the failure of quadraphonic sound," "the fading of four-channel sound," etc. How do you feel about this?
J: Many people have only a limited or superficial viewpoint of the quadraphonic scene, and I can understand why some of the entrenchment that has occurred in this field could cause some negative opinions. But four channel sound is anything but dead. I think it is best described as in a dormant state or displaying a very low profile. It must be noted, that although quadraphonic sound enjoyed quite a bit of activity in its early stages, for many reasons it was not properly brought to maturity.
B: In other words, it was brought out because the audio industry was looking for something new to improve the sales and profit picture, but unfortunately it was introduced prematurely, with many of the technical problems unresolved.
J: The crux of the problem was that the kind of quadraphonic equipment and some of the software that was originally sold to the consumer did not have the technical quality to impress and excite the consumer to a high level of interest in four-channel sound.
Four-Channel Consumer
B: Quite true, however, I think we should define what we mean by a "quadraphonic consumer." There certainly was a large amount of very poor quality, mass market type-of four-channel equipment sold, but most of the people who bought it were not discriminating enough to be annoyed with its shortcomings. I assume the consumer you refer to is one of that large group of people who own stereo component systems, but have not quite attained the status of audiophiles. Their opinion certainly has weight, and 1 should think that they constitute a large segment of the potential quadraphonic market.
J: I think quadraphonic sound is for everyone who has stereo and an interest in high-fidelity sound. They will like any system which can offer a substantial and easily perceivable increase of realism in the music they enjoy. You know, stereo was a dramatic improvement over monophonic sound, and when four-channel sound came along, they were expecting something equally spectacular. Because of poor equipment and misguided merchandising, many felt the improvement of quadraphonic sound over stereo was only marginal.
B: I couldn't agree with you more, Jerry, and unfortunately one of the factors that caused problems right from the beginning was the existence of three different systems for quadraphonic sound, your Sansui QS matrix, the CBS SQ matrix, and the JVC/RCA discrete CD-4. When the battle was joined among the competing systems, each touted their superior qualities, with the natural consequence that the consumer was more confused than enlightened.
When it dawned on the three competitors that it might be to their advantage to "bury the hatchet" and jointly promote the overall concept of quadraphonic sound, it may have been too late.
J: Bert, you talk about three quadraphonic systems, but it must be remembered that much of the equipment was marked with such designations as Matrix 1 and Matrix 2, and Composer A and Composer B, plus RM, QS, SQ, and CD-4...no wonder the consumer was confused. Undoubtedly it would have been advantageous to have promoted quadraphony, rather than the particular systems.
B: Of course, one of the big problems with the three systems was that none of them had really achieved technical maturity. This was immediately noticed by the more discriminating audiophiles, and quadraphony got off on the wrong foot.
J: Unquestionably, the quality minded consumer was used to a very high level of excellence in stereo, with low distortion, good signal-to-noise ratio, wide dynamic range, extended bass response, good channel separation, etc., and he expected that quadraphony would be an extension of these parameters into another dimension. When the early four-channel equipment compromised the high standards of stereo in order to sell quadraphony at a reasonable price, this was not acceptable to the audiophile and the more knowledgeable consumers.
B: Jerry, you are aware that your Sansui QS system was some time in coming to your present high quality Vario-matrix circuit, and the same thing can be said of the SQ system, which went from the most simple basic matrix to the advanced logic with variable blend circuitry. CD-4 was the most technically complex of the three systems and had more than its share of problems. We in the audio press had the responsibility of reporting on the development of these systems, and as the consumer read these changes, you can't blame them for feeling that the audio industry had gone into quadraphony a bit too early.
J: Well, it is easy to carp, but it is true that in the early days the three systems were quite rudimentary. The time it takes to develop integrated circuit chips for any decoding or demodulating system is substantial, and any chip requires a great deal of effort and quality control to make it work properly. Many manufacturers tried to bring out receivers without IC chips, and these were strictly compromise units. Now, QS, SQ, and CD-4 systems all have IC chips that are the main parts, the integral parts of their circuits, and can fairly well be mass produced.
Three In One
B: Unfortunately, now that we have achieved a high degree of sophistication and good quality in the various chips, no receiver, at least none on the market that I know of, employs all three systems to maximum advantage.
J: That's correct. Manufacturers have found the cost of incorporating all three systems into a receiver would substantially raise the price of the unit. So they compromise by choosing to put in chips for two of the four channel systems and use discrete components for the other system (usually of lesser sophistication). I think Sansui came quite close to a high quality universal quadraphonic receiver when they incorporated their Variomatrix with its own SQ decoding circuitry, plus CD-4 in their QRX units about a year and a half ago. The only thing that it doesn't have is the CBS logic system, because we feel the technology of vario-matrix decoding is perhaps more advantageous than for logic decoding.
B: Getting into software, one of the early complaints about quadraphonic sound was that all three systems suffered from a scarcity of four-channel recordings, both in the popular and classical formats. Peculiarly, now that there are several thousand quadraphonic recordings available in the three systems, many people, including sections of the audio press, seem to think that the software shortage is still a problem.
J: I don't know why this notion hangs on, but in the early days of quadraphonic sound, there was indeed a lack of four-channel software, and I'd like to lay the blame squarely in the laps of the record companies.
Record companies never seemed to take the initiative in terms of a major promotion to make four-channel sound ultimately successful. For example, the record companies got involved with quadraphonic experiments with the various systems, but they never really got behind anything and said they were going to produce four-channel records on a single inventory basis. The record retailer must also share part of the blame for the software shortage. Probably because of lack of information from the record manufacturer, the retailers felt that four-channel records were a breed apart from stereo records, that compatibility was non-existent, and therefore they segregated quadraphonic records from standard stereo production, much as they do with bird calls and ethnic music. This cut down on the exposure of a company's artist, who happened to be recorded in four-channel sound, since the retailer relegated the record to his quadraphonic bin, in an out-of-the-way corner of his store. Thus there was a reluctance on the part of the record companies to release four-channel records and mark them as such.
Single Inventory
B: Jerry, you recall that when RCA introduced the CD-4 discs, they were brought out in the single inventory mode, which of course was favorably received by the record dealers. But after a relatively short period they converted to a policy of double inventory, with a CD-4 recording and a stereo recording of the same program. Now we have the situation where almost every company which produces quadraphonic recordings is on the double inventory basis.
J: The idea of a single inventory was one of the guiding factors on which the QS process was founded. We have always felt that for a record company, and especially for a broadcaster who only has one option, that you must provide an acceptable stereo/ monophonic playback as well as quadraphonic capabilities on your record. Since the inception of QS, record companies using this system such as Ovation, ABC Dunhill, and Vox Records, and their European counterparts, Pye Records and French Decca, produced quadraphonic records in the single inventory mode.
They evidently have faith in the stereo/mono compatibility of QS recordings.
B: I believe you have just returned from the convention of the National Association of Broadcasters where you noted that there is an ongoing interest in four-channel broadcasting.
Whether the stations use your QS matrix system or the SQ matrix system, such broadcasts are increasing every month. Don't you think it is rather paradoxical, that with all this talk of "quadraphonics is dead," that four-channel broadcasting is in such a healthy state?
J: I certainly do! Four-Channel Broadcasting
B: Many stations boast of 24-hour quadraphonic broadcasting, and while there are a substantial number of four-channel records available, one presumes that they are taking stereo recordings and running them through matrix synthesizers in order to have sufficient "four-channel" material for the 24-hour schedule.
J: Stations want to maintain a certain format in broadcasting quadraphonic sound, so that the listener at home does not continually have to use the four-channel mode switch on his receiver. They take whatever four channel product is available and reduce it to one format. In other words, CD-4 and SQ records are decoded, re-encoded into the QS encoder, and then broadcast in the one transmission mode. And of course as you point out, there is extensive synthesizing of stereo discs through the QS encoder.
B: Did you hear anything at the NAB convention about when the FCC may make a decision on the broadcasting of discrete quadraphonic sound?
J: The FCC has a number of problems right now which far overshadows their interest in four-channel broadcasting. The vast backlog of Citizens Band license requests are absorbing a great deal of the Commission's time, as is the proposal of reducing FM interchannel bandwidth from 200 kHz to 150 kHz, as it currently is all through Europe.
B: Did anyone at the NAB convention bring up the subject of using Dolby with quadraphonic transmissions? J: As a matter of fact, yes. A number of broadcasters asked us about the use of the QS encoder with Dolby, and we assured them that it was totally compatible. Probably a third of our 82 stations who are using the QS encoder also have Dolby encoders and are experiencing no problems.
B : Of course, there are no quadraphonic receivers from Sansui that have Dolby 25 microsecond facilities. So I presume listeners would need an outboard Dolby unit.
J: That is correct.
B : It occurs to me that this might be one avenue or approach to building new quadraphonic equipment, if things loosen up a bit.
Jr. There is no argument that quadraphonic sound is in a dormant state, but a lot of things are going on behind the scenes. There is definite activity in Europe, most specifically in Great Britain. For a number of years the British Broadcasting Corp. has been studying four-channel broadcasting and is coming fairly close to making some formal public statements about what they will accept and will adopt for a universal standard in England. I believe this will have a significant impact on American broadcasting.
B: As a spokesman for Sansui, are there any new quadraphonic receivers in the works for the Consumer Electronic Show in June in Chicago?
J: Sansui is one of the few manufacturers who have continued to produce and sell four-channel receivers.
We do have some plans, which I can't reveal at this time, but a new decoder, a new Variomatrix unit, the QSD-2 will be available, which will feature QS and SQ decoding along with two synthesizer functions. Several other companies are working on incorporating QS decoders into existing equipment, but it is difficult to tell whether they will be ready for the June Show.
B: Summing up, Jerry, it would appear that those who say that quadraphonic sound is dead are not correct...on the other hand we do admit that it is at a mighty low ebb, and my last question is what can we do to get four-channel sound going again?
J: I don't want to suggest that things will be better overnight, but sooner or later, the trial of the marketplace will shake out the three systems, and there will be a decision as to which technology is the most acceptable to record companies and broadcasters alike.
When that is decided, the hardware people will move very quickly to produce appropriate equipment, and quadraphonic sound will be back and rolling.
==============
The Bookshelf
Sound System Engineering by Don and Carolyn Davis, 295 pages, 8 1/2x 11, Howard W. Sams, 1975. $19.95.
The eagerly awaited Sound System Engineering has arrived, bringing us rewards for our patience. Some portions of the text will be familiar to readers of Audio who have been enlightened by Don Davis' articles on speaker directivity and related subjects. That should whet the appetite for this in-depth treatment of those audio-acoustic areas that have been confusing to many.
The book fulfills the serious need for a one-stop source of information on taming the wild beast of sound reinforcement. After a chapter which provides clarification on decibel notation and usage, there are chapters on Loudspeaker Directivity, The Acoustic Environment, Acoustic Gain, and Interfacing The Electrical And Acoustic Systems. The text provides sufficient detail for the majority of readers to understand the theory and the necessary approaches to design. Those portions of the sound system that provide amplification and mixing are touched upon briefly.
Sound System Engineering is generally pitched to the contractor, but it should be useful and interesting to anyone involved in sound reinforcement. A chapter on installation includes valuable material on grounding, shielding, impedance matching, and time delay. Equalizing the Sound System gives both broad subject coverage from older methods to the real-time analysis now possible and critical examination of pertinent equipment characteristics, such as filter combining. There are also chapters on Instrumentation, Sample Designs and Specification Writing.
There are 11 appendices of various lengths and an adequate index. Worthy of particular note is the section on installation practices with very good coverage on both soldering and cabling. A listing of useful equations, a bibliography, and test questions and answers are also among the other helpful features. The printing and production of this hard-cover book is good with clear, pertinent, and up-todate illustrations. The level of presentation is generally consistent and lucid, with just two unimportant errors noted. Sound System Engineering has a large format which provides twice as much material per page as the usual 6-by 9-in. book. As a result, it is effectively a "600-page" volume, putting it into the "good-buy" category. In a paraphrase of the authors' comments at the end of a chapter, this recommended book "will serve as a useful review for those already expert in this field and as a firm base for the person seeking to develop and expand his capabilities." Howard A. Roberson The Complete Encyclopedia of Popular Music And Jazz, 1900-1950, Roger D. Kinkle. Four volumes, 2644 pages.
Arlington House, 81 Chester Ave., New Rochelle, N.Y. 10801, $75.00. This four-volume set is the definitive data bank on American popular music and jazz for the first 50 years of this century. The coverage is exhaustive, including: Movie Musicals (1,230) casts, songs, composers, 'year of release; Performers (11,505) all major (and most other) singers, bandleaders, musicians, composers, actors, arrangers, and impressarios, each with a career summary, key dates, film and Broadway credits, recordings, and compositions (by year). In brief, there is virtually every pertinent public fact about each performer and artist here.
The 100 to 200 most popular songs are listed by year along with their composers and the artists usually identified with them, plus another 20,000 which came out less successfully during that time. There are also the outstanding, and the typical, popular recordings from the first discs (78 rpms) in 1904, as well as outstanding jazz records starting with the Original Dixieland Jass Band in 1917 about 75 a year. In addition, it includes a broad, in-depth discography for every performer. Further, all known Broadway musical shows are listed with their casts, playwrights, songs, and composers; a total of 1,522.
There are four massive indexes: 28,161 songs, 11,505 performers, 1,230 movie musicals, and 1,522 Broadway musicals. Five more indexes include a numerical listing of all discs released by the nine major companies from the mid-20s through the early 40s, by artist as well as song 33,000 recordings.
There are also the Academy Award winners and nominees from 1934 through 1973, along with all the Down Beat and Metronome magazine jazz poll winners from 1937 through 1973.
This is a unique reference work, absolutely essential to anyone writing on musical history of the first-half century of American jazz, popular music, movies, or musical comedy. No columnist, critic, biographer, or any other writer on these subjects can afford to be without a copy of this reference work. I've already sent off my $75 for another set.
Charles Graham
(Audio magazine, 1976)
Also see:
Energy-Time Test/Richard C. Heyser
Making Records/Ralph Cushino
= = = =