V 0011-7145

THE SOUND ENGINEERING MAGAZINE AUGUST 1975 51 00

A View of Electronic Music

Operations of Moog Synthesizer Modules and Components

In the CD -4 Groove

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Studios by design...

not by accident

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Accept our invitation to contact us and discuss your studio needs. 14045 Sherman Way. Van Nuys. California 91405 / (213) 873-44 www.americanradiohistory.com =ling month

Ingenuity in the use of micro- 0 phones is the theme of two workshop -ED articles coming in September. THE SOUND ENGINEERING MAGAZINE

AUGUST 1975, VOLUME 9. NUMBER 8 Michael Rettinger tells us how to Calibrate Microphones by Reciproc- ity. The secret is in using rapid alter- nation of loudspeaker transducers.

A Simple and Superior Microphone Preamplifier is described by R. S. Mintz. The device uses an integrated 12 IN THE CD -4 GROOVE circuit and a minimal number of ex- Edward Horn ternal passive components. 15 THE NEW YORK EXPERIENCE The first of a three -part series on Martin Dickstein Feedback by Norman H. Crowhurst deals with its effect on gain, distortion. 25 OPERATIONS OF MODE SYNTHESIZER and impedance as well as negative and positive feedback. and phase. MODULES AND COMPONENTS Robert C. Ehle 30 A REALISTIC VIEW OF ELECTRONIC MUSIC David Cope

2 LETTERS 4 INDEX OF ADVERTISERS 6 CALENDAR

7 FREE LITERATURE

8 THEORY AND PRACTICE Norman H. Crowhurst

11 SOUND WITH IMAGES Martin Dickstein 20 NEW PRODUCTS AND SERVICES 33 CLASSIFIED 36 PEOPLE, PLACES. HAPPENINGS

db is listed in Current Contents: Engineering and 'technology

Robert Bach Larry Zide PUBLISHER EDITOR Bob Laurie John Woram ART DIRECTOR ASSOCIATE EDITOR Eloise Beach Hazel Krantz CIRCULATION MANAGER COPY EDITOR Crescent Art Service Ann Russell gout GRAPHICS PRODUCTION

db. Sound Engineering Magazine is published monthly by Sagamorc Publishing Company. Inc. Entire the V.Y. That's Roger Powell at the Moog contents copyright © 1975 by Sagamorc Publishing Co., Inc., 1120 Old Country Road, Plainview. L.1.. 1114113. Telephone (5161 433 6530. db is published for those individuals and firms in professional audio- Synthesizer. Photo copyright 1974 by recording. broadcast, audio- visual, sound reinforcement. consultants. video recording. film sound. etc. Appli- cation should be made on the subscription form in the rear of each issue. Subscriptions are $7.00 per year Alan F. Blumenthal and used with (512.00 per sear outside U. S. Possessions, Canada. and Mexico) in U. S. funds. Single copies are $1.00 each. Controlled Circulation postage paid at Harrisburg. Pa. 17105. Editorial, Publishing. and Sales Offices: permission. 1120 Old Country Road. Plainview, New York 11803. Postmaster: Form 3579 should be sent to above address.

www.americanradiohistory.com THE EDITOR: The O O letters With reference to your listing of suppliers of audio gear in the San Francisco area in your June issue. please accept an indignant "You left CROWN me out" complaint. The Langevin THE EDITOR: Company. Inc. is the oldest firm in Towards the end of May, we wrote this area, supplying and installing pro- VFX -2 to you asking for possible manufac- fessional audio systems and equip- turers of RC -10 caplugs. As per your ment since 1927. We represent many electronic crossover suggestion, we have written to both of the top quality professional audio Commercial sound contractors Atlas and Beyer, only to receive "No" equipment manufacturers as well as across America have been asking answers. Perhaps one of your readers custom -building systems for specific for an electronic crossover for use might have this information? requirements. on sophisticated sound installa- BILL BEATTY Thanks for the opportunity to cor- tions. There's no more waiting. And DAVE BEATTY STUDIOS rect this oversight. the Crown VFX -2 embodies all you 1414 S. 5th H. A. WOLLENBERG. President expect in high quality and perform- Springfield. Ill. 62703 THE LANGEVIN COMPANY. INC. ance capabilities from the people at 1050 Howard St. Crown. San Francisco, Ca. 94103 Only the Crown VFX -2 electronic crossover will give every installa- THE EDITOR: THE EDITOR: tion maximum versatility. Such In the June issue, a letter from Just read Bob White's flexibility for so little cost. And George W. Hamilton on page 2 caught article. "A Simple High -Quality never before has an electronic my eye. I have Mr. Hamilton beat by High -Speed Tape Duplicator," in the May issue and I crossover been offered that can be a long time! want to inform you that I have a easily and readily adjusted with I was the first chief engineer of the front panel controls. Syracuse Radio Workshop, the pre- model 970 Ampex if anyone is inter- ested in buying it. Tunable from 20- to 20,000 Hz, decessor of WAER during the years this solid state component is com- 1937-1938. The installation was built D. M. Wesenbcrg Rd. patible with 600 ohms loads and up, in the basement of the library build- 1904 Harlan Toledo, and features both balanced and un- ing and consisted of two studios and a Ohio 43615 balanced inputs and outputs. control room. The equipment was Overall noise and distortion are Western Electric, vintage of the early extremely low. IM distortion is less 30's, donated by WFBL when that than 0.010/0 rated at output, and station replaced it with more modern you write it noise is more than 97dB below gear. The amplifiers used the old rated output with open inputs. round bulb tubes, whose type num- Many readers do not realize that Providing either crossover or bers I cannot recall. The microphones they can also be writers for db. bandpass functions, the VFX -2 uti- were the Western Electric condenser We are always seeking meaning- lizes two continuously variable fil- microphones with the small vacuum ful articles of any length. The ters per channel, and filter roll -off tube amplifiers built into them. They is a fixed 18 subject matter can cover almost at dB /octave. were built into cylindrical cans which Applications include stereo bi- anything of interest and value to weighed a ton (so it seemed). amping, mono tri- amping, and com- audio professionals. There was no f.m. in those days. bining the bandpass with You filter the Programs were produced for both don't have to be an expe- normal two -way crossover on a WFBL and WSYR. When we went on rienced writer to be published. mono signal. And all connections WSYR, the call sign. WSYU, was But you do need the ability to are quarter -inch phone jacks for used (same transmitter, different call express your idea fully, with ade- positive electrical contact. sign). Their transmitter was located quate detail information. The VFX -2 is designed for stand- and Our on the university campus in those ard 19" rack mounting and meas- editors will polish the story for days, and was 250 watts to a single ures in at 3'/2" high by 53/a" deep you. We suggest you first submit vertical radiator. The transmitter had and includes a clear plastic cover an outline so that we can work formerly been one which was built by for protecting control settings. with you in the development of Clive B. Meredith of Cazenovia, N.Y., the article. who started WSYR as WMAC in his home. You also don't have to be an Professor Kenneth Bartlett, later to artist, we'll re -do all drawings. become Dean and then Vice -Chan- This means we do need sufficient cellor, was the director of the Radio detail in your rough drawing or Write for complete Workshop. Operating that setup, an- schematic so that our artists will specif ícations. tiquated as it was, was good fun, and m understand what you want. we it very The took seriously. Work- It can be prestigious to be pub- shop produced some very famous lished and it can be profitable z in too m people broadcasting, numerous u to mention here. too. All articles accepted for pub- Just a bit of nostalgia from those lication are purchased. You won't old days. retire on our scale, but it can PAUL H. LEE, President make a nice extra sum for that P. H. LEE ASSOCIATES. INC. special occasion. crownBOX 1000 ELKHART. IN 46514. 219 294 -5571 (V Thousand Oaks, Ca. 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Circle 16 on Reader Service Card www.americanradiohistory.com CALENDAR After you use the 1056, we'll know SEPTEMBER one thing about your dub quality: 15- 17 NOISE -CON '75 National Con- ference on Noise Control En- it just got better. gineering. Gaithersburg, Md. Pre -seminar at the Shoreham Professional studios that make lots of dubs for radio, welcome the speed Hotel, Washington, D.C. Sept. and quality they get using the Garner 1056. It offers a whole new set of 11 -13. Contact (914) 462 -6719. advantages for producers of reel -to -reel duplicates for radio, AV, or 21 -24 International MUSEXPO '75, educational needs. Some of those are: Single capstan drives the master Las Vegas, Nev. Contact: Rod- and all five copies. Solid -state electronics and special heads provide dy Shashoua, International outstanding frequency response. Two -speed drive allows either 30 or MUSEXPO, 1350 Ave. of the 60 i.p.s. duplicating. Extra -fast rewind of master tape speeds produc- Americas, New York, N.Y. tion. Unique forward tilt of transport mechanism aids threading. 10019. (212) 489 -9425. Conveniently located controls feature push button operation. 28- SMPTE Technical Conference Oct. 3 and Equipment Exhibit. Cen- tury Plaza Hotel, Los Angeles. Contact: SMPTE Conference, 862 Scarsdale Ave., Scarsdale, N.Y. 10583. 29-30 N.Y. Chapter of ERA, Com- mercial Sound & Communi- cations Show, Statler -Hilton Hotel, New York City. Con- tact: GIM Sales Corp., 375 N. Broadway, Jericho, N.Y. 11753 (516) 433 -4080. GARNER INDUSTRIES First Congress of the FASE -1200 NORTH 48TH STREET on Acoustics. Groupement des LINCOLN NEBRASKA 68504 Acousticiens Francaise (GALF). Paris, France, Secretariat: Circle 17 on Reader Service Card C.N.E.T., Issy -les- Moulin -eaux 92, Paris. OCTOBER Fall Conferences, National As- sociation of Broadcasters. Con- ForTape Heads tact: NAB, 1771 N St., N.W.. Washington, D.C. 20036. (202) 293 -3500. Head for TABER 12 -14 Atlanta 15 -17 Boston At Taber you get precision work, quality results and low price ... 21 -26 International Audio Festival unmatched by any other audio head manufacturer. Fair. London, England. Con- TABER professional audio heads are available in full track through tact: British Information Ser- 16 track configurations including /<" 4 channel for your Ampex 440 vice, 845 Third Ave., New series and Scully 280 series recorders. York, N.Y. 10022. (212) 752- TABER provides expert and prompt reconditioning service for all 8400. audio head configurations. NOVEMBER Loaner assemblies are available. 3 -31 Audio Engineering Society 52nd For heads, head for Taber ... the best source available. Convention, Waldorf- Astoria Send for free brochure. Hotel, New York, N.Y. Con- tact: AES, Room 929, 60 E. 52nd St., New York, N.Y. 10017. (212) 661 -8528. 4 -7 Meeting of the Acoustical So- ciety of America, San Fran- cisco, Ca. NAB Fall Conferences. Con- tact: NAB. 1771 N St., N.W., Washington, D.C. 20036. TABER (202) 293 -3500. 9 -11 New Orleans Manufacturing & Engineering Company 12 -14 Chicago 2081 Edison Ave. San Leandro, Ca. 94577 (415) 635 -3831 16 -18 Denver 19 -21 San Francisco Circle 18 on Reader Service Card www.americanradiohistory.com FREE LITERATURE INTERCONNECTION MOLDINGS To obtain the tree literature described, Specialty moldings, test fixtures, test please circle the appropriate number on sockets and die stamping and die the Reader Service Card in the back of forming are described in this bro- the magazine. chure. Mfr: Plastronics. Circle No. 87 on R. S. Card.

D.C. POWER SUPPLIES Covered in this catalog are bench - MEASUREMENTS type units for circuit testing and de- velopment, modular supplies to power PORTABILITY . . . And Your systems, -power supplies used in Best -Buy Instrumentation for Sound high industrial processes and special pur- & Vibration Measurements is the title pose units. Co. of this brochure. Material includes Mfr: Hewlett- Packard graphic comparisons of analyzers, Circle No. 88 on R. S. Card. meters, specialized measurement equip- POWER DARLINGTONS ment, and recorders. Mfr: B &K In- Graphs and diagrams illustrate this Top Disc Cutting struments, Inc. data sheet on 125 watt high voltage Circle No. 80 on R. S. Card. monolithic Darlingtons. Mfr: Inter- Studios, like The VIDEO CASSETTE PROCEDURES national Rectifier. Proper handling and storage pro- Circle No. 89 on R. S. Card. Mastering Lab, rely cedures for video cassettes is the topic on Stanton's 681 - of the Spring issue of Scan, a four - MICROPHONE USE FOR MUSICIANS page newsletter published for video "The Music- Maker's Manual of Calibration Standard tape users. Mfr: Memorex. Microphone Mastery" describes in Circle No. 81 on R. S. Card. non -technical terms how to mic pro- in their Operations. fessionally voices and instruments, METERS AND RECORDERS Not everyone who plays records needs with listings of proven techniques for This 60 -page instrumentation cata- the Stanton Calibration Standard cartridge, handling especially troublesome sound but log describes over 2,000 stock ranges, everyone who makes records does! pick -up situations. Specific micro- At The Mastering Lab, one of the world's digital sizes and types of analog, and phones for various instruments and leading independent disc mastering facil- AnaLed panel meters, chart record- situations are specified. Mfr: Shure ities, the Stanton 681 Triple -E is the mea- ers, meter relays, pyrometers, con- Brothers, Inc. suring standard which determines whether trollers, digital and analog test equip- Circle 14. 95 on R. S. Card. a "cut" survives or perishes into oblivion. ment, and portable instruments. Mfr: A recording lathe operator needs the Simpson Electric Co. AM STEREO SYSTEM most accurate playback possible, and his Circle No. 82 on R. S. Card. constant comparing of lacquer discs to Evaluation criteria for a.m. stereo their original source enables him to ob- broadcast discussed in INFORMATION CASSETTE LIBRARY systems are jectively select the most faithful cartridge. this booklet. It describes the system No amount of laboratory testing can reveal Catalog contains over 200 cassettes which RCA demonstrated at the 1975 true musical accuracy. This accuracy is on Management, Data Processing- National Association of Broadcasters why the Stanton 681 Series is the choice Technical, Computer Design /Com- convention. Mfr: RCA. of leading studios. puter Aided Manufacture, Instrumen- Circle No. 97 on R. S. Card. When Mike Reese, principal disc cutter tation, Production and Inventory Con- at The Mastering Lab, plays back test cuts, trol, Metals, and Software Industry he is checking the calibration of the cutting Development. Mfr: Information Cas- channel, the cutter head, cutting stylus, and the lacquer settes, Inc. IT'S A SMALL WORLD! disc. The most stringent test of all, the evaluation of direct to disc No. 83 R. Circle on S. Card. SMALLER AUDIO TRANSFORMERS recordings, requires an absolutely reliable Sizes: 1 -3/8" x 1- 15/16 ", 15/16" x 1 -1/4 ", playback cartridge ... the 681 Triple -E. 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DIGITALS empty tape reels For further information write Timers for broadcast and industrial o -\ wand boxes Stanton Magnetics, Inc., Terminal Drive, needs are detailed in a 7 -page bro- Plainview, N.Y. 11803 chure. Mfr: ESE D hi -speed duplicating Circle No. 85 on R. S. Card. i7for audio spots - tv spots SPECIALTY ALLOYS IMMEDIATE SHIPMENT Vacuum -melted alloys for electrical F R GMT ALTO STOCK and electronic applications are des- CATALOG PD 175 cribed in bulletin EA -03. Mfr: Mag- Polyline CORP. 312/298.5300 All Stanton cartridges are designed netics Specialty Metals Division. 1241 Rand Rd. DesPlaines, IL 60016 for use with all two and four- channel Circle No. 86 on R. S. Card. matrix derived compatible systems. V Circle 31 on Reader Service Card Circle 20 on Reader Service Card

www.americanradiohistory.com crzpitheory&pracuce o o Before leaving conventional tests, NORMAN H.CROWNURST we should comment a little more on what such tests mean against their more common background. Almost nothing, as we have said before. All they show is that the student can re- The more we get into educational and you cannot sell mathematics to gurgitate what he has recently been use of media, which involves some them anyhow. And really you cannot shown. A parrot or a monkey, prop- really wonderful opportunities to use blame them. Learning math that corn - erly trained, could probably do bet- one's creativity, the more we also run partmented way makes no sense what- ter than most human students. across the same obstacles. And as ever. Added to this is the fact that stu- readers of this column will undoubt- But learning Problem Solving Arts dents conventionally work, often quite edly get into the same spots sooner or gets to be fun, for anyone. However, hard, at being able to pass tests, rather later, it should be helpful for me to administrators, teachers and others than at learning the subject. When pass on some of my own experiences. now mess things up by throwing a you realize that learning to pass tests whole bunch of compatibility prob- is much harder than learning the sub- COMPATIBILITY lems at you. Oh, they won't call them ject so you can pass any test on that Audio people have met this gent compatibility problems -as we said, subject, you will wonder, as we did, before when we made the step from they don't know the word, yet! But how so many people could be so mono to stereo, first in disc, later in the way they've been trained, after a stupid! multiplex f.m. and more recently as student is exposed to a certain course, we became involved with various he must be given a test to prove that TITLE COMPATIBILITY things called quadriphonic. So the he's absorbed an adequate amount of What we have just been saying problems of achieving compatibility instruction. could apply equally well to a course are not new to us. But they sure are in English, physics, or just about any to educators and teachers. TESTING AND TESTING subject you could name. The case we Sometimes this poses tougher prob- There are different attitudes to were discussing happened to be mathe- lems than at others. For example, for tests. First, there is this compatibility matics vs. Problem Solving Arts. How- my mediated English course, and my question: if the student learns it the ever, regardless of whether the stu- physics course, there was not much Problem Solving Arts way, will he be dent ultimately learns the same thing problem: just give the course the tra- able to satisfy the traditional form of or not, or whether he learns it better, ditional name, and handle it differ- test, based on the algebra, geometry, titles are very important in education. ently. Maybe that only postpones the algebra 2 sequence? If you are pre- When you look at a school or com- compatibility problem until the teach- paring a course, such as the Problem munity college catalog, you find there ers have it in the classroom, but it Solving Arts course I prepared, then are two kinds of courses: credit and does at least get things started. this must be one of your requirements. non- credit. Credit courses pay the in- With mathematics we had a much You design the course, as we did, so structor more, for one thing. But tougher problem. There are already that as well as coming to grips with students are also more interested in what should be more than enough the subject, and knowing it much bet- credit courses, because those little courses on mathematics: old, many ter than he would by learning it the numbers called credits count toward kinds of new, and all kinds of in -be- traditional way, the student can also some paper qualification that seems tween. Yet none of them seems to satisfy any test based on the traditional vital to him, whether or not it means have made mathematics either enjoy- method of learning it. he knows something. able, or convinced people who have That may sound like a tall order. So, given this alternative we are already been turned off by the very Actually, it is a piece of cake, pro- talking about, the already accepted word that it's not beyond them at all vided you accept the fact that you math courses, some of them at least, when you approach it in a sensible must do it. The only thing that could carry credit, but give the same ac- way. conceivably throw the student in a quisition of knowledge and skills the The only place you will find mathe- conventional test is not knowing what name "Problem Solving Arts," and matics being approached sensibly so some of the words mean. There is no bang goes the credit, for both instruc- people are turned on by it and start doubt that he could solve the prob- tor and student. So what can you do? learning easily, is in the classroom of lem, but he may not understand what You have two options. One is to an individual teacher who has that the question means. Of course, that offer Problem Solving Arts, with the capability. We have already proved situation is not new-plenty of stu- promise that, after successfully taking that it is impractical to start trying to dents who learned by the traditional it (and pointing out that it's much change all existing teachers. We have courses have run into that! easier to take) you will be able to also proved that a well -written text- So you design the course so while successfully challenge specified math book can work, provided some ob- primarily covering the subject, it also credits or whatever subject is involved. noxious teacher doesn't get in the way, gives the student confidence in his For some purposes this might be best, and that individualized mediated in- own ability to solve problems. Then but we will not digress into the eco- struction, which helps keep the teacher you fill in with the fancy words he nomics and finances involved, because out of the way, can also make it may meet in conventional tests, and these differ from place to place. happen. that won't take long when he knows The other option is to offer the But then the compatibility thing the subject anyway. We have always course as the math course whose credit comes in, a little differently than with found that you can help the student will ultimately be achieved, merely other subjects. If you call it "mathe- learn the basics of the subject, fill him changing the approach used in pre- matics," the very word conjures up in on all the possible variations he senting it without altering its title. But a barrier against you. Most of the may encounter in various tests, and here again, you cannot just do this if students have seen such horrid things still have time to spare over that taken the institution for which you are do- co as fractions, algebra, geometry, etc., by teaching it the conventional way. ing it happens to specify that the text

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pushbutton -selected 16 or 35 speed and 24 or 25 frame rate, forward or reverse local inching forward or reverse plug -in head assemblies for play -only or erase /record/ play. interchangeable for 16. 35. 171.2 and multi- tracks multi -track pick -up recording with selective erase 3000- foot (1000- meter) reel capacity HIGH -SPEED ELECTRONIC INTERLOCK IS NOW A PRACTICAL REALITY N

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CINESOUND INTERNATIONAL. LTD. . IMPERIAL STUDIOS. MAXWELL ROAD. BORLr,AMWOOD. ENGLAND MAGNA -TECHTRONICS ;AUST) PTY LTD 49 WHITING ST ARTARMON N S W AUSTRALIA 2064 (O Circle 21 on Reader service Card www.americanradiohistory.com theory & practice (cont.) deep dark secret about it? And at first, that is all the student or examiner used shall be Admiral Cornwallis' wants to know -not how quickly! Mathematics From the Ocean Floor When the student has established that Up! You will need to get a variance he can do whatever it is, it is quite time The or at least come to an understanding, enough for him to see how quickly he whereby you guarantee results, or can do it. But that often is not the something. way things are. This title compatibility can be a Probably because this has been the tough nut to crack, but creativity way exams and tests have been re- should always prove at least equal garded, that is the way that teachers price use them. To get back to what we to stupidity! were talking about last month, I.Q. BETTER FORMS OF TESTING tests: we have these various tests- Being able to meet existing test re- aptitude tests, and so forth-each of sults should not be the objective. We which is handed down, like a mea- of want to produce better learning out- sure designed by God himself, and the comes and to prove that we are doing teachers rely, with incredible faith, so. Relevant to this is a question that on the results. my spring class in metric systems By some magic, whatever the words asked me, after some of them had or pictures to which the student re- Id confessed to suffering from "exam sponds, that I.Q. test will measure the phobia." Why do people who really students' I.Q. And because, according know the subject go all to pieces when to some psychologists at least, a per- they hear the word "exam," or "test "? son's I.Q. does not change, what that We discussed it, and concluded that test measures is unchangeable, too. We it stems from a particular way in have seen countless examples where just which tests or exams are applied, from a student's scoring, say 75 in a par- the early days, when children are in ticular I.Q. test, has had that student the lower grades. The problem has a marked as a moron for life! number of superficialities, but perhaps A typical teacher response will be the most dominant one is that of like the professor I was talking about went working against the clock. When a last month, "Can't expect any more test is on, you have 30 minutes (or of him, he has an I.Q. of 75!" Come whatever) to complete the answering to think of it, did I say he was jok- of these questions. Another piece is ing? I'm not so sure he was. People the way questions are asked. Design- who believe in I.Q. results place im- down. ers of tests seem to have a creed that plicit trust in those figures as if they the student shall not be allowed to magically must be right. Can such a guess what answering a particular test tell how much intelligence a per- Because with Memories Little Helper question correctly tells the examiner son possesses? by Allison and Memories Control Is intelligence a purely about him. quantitative thing, or does it have a Master by fx, you can now achieve Why not? Why the mysticism at- quality, differing for every individual? fully automated flexibility in your tached to testing? The student, as well How can a test tell about that? studio for less than 1 /5th the cost of as his examiner, should want to know, is a fully automated mixing A difficulty that people either be- board. "Can I solve this kind of problem These units work together to give lieve, implicity, in I.Q. tests and what correctly, or can't I ?" So why the you the affordable automated mixing they are supposed to tell, or they system encompassing all the special don't. The mystique of testing blurs effects and features that mean golden everything. We need tests that tell chart results for your clients. MOVING? something, that a person can tell about You're invited to experience the himself, as well as giving others in- automated mixing capabilities of this formation about him. When tests are Keep coming Allison /fx system for yourself. Call db designed with that frank objective 215-561 -2178 (in New York City call without interruption! they become meaningful and helpful. 212- 966 -1255) for details. They also become part of the learn- Who knows? It could be the first of Send in your ing process, rather than a separate en- tity in themselves. many Gold Record sessions for your new address promptly. studio. Space has gotten away from us this Enclose your time. Another time we must give some dimensions that can be built into db mailing label. too. mediated material by which such meaningful tests can be made, and in- Write to: tegrated into the learning process. One would think that such aspects Eloise Beach, Circ. Mgr. would be the subject matter expert's db Magazine domain. But it is apt to fall to the audio man by default: if we don't do incorporated 1120 Old Country Rd. something about getting these dimen- 212 North 12th Street. Philadelphia. PA 19107 Plainview. N.Y. 11803 sions in there, education will continue to deteriorate, the way it has the last few decades, media or no media. Circle 22 on Reader Service Card www.americanradiohistory.com MARTIN DICKSTEIN able between 90 percent and 110 per- cent "rated volts," with reliability de- al sound with i creasing as values depart from this range. There is a bit more information on the reverse side which GE calls Ad- Every time we get away from pro- requirements, you may cause a mal- ditional Information: out function shorten the life jectors, it seems that our friends or of your 1. The life rating of a lamp is ac- there bring us back again with the equipment. PLEASE leave the 3 -in- tually the median life obtained by mails, and we're glad. One oil in mother's sewing chest! testing many lamps over a long period up the work. I will look This first letter was written on May Keep good of production. At rated voltage, one - 22 by Ken Stoltenberg of Electronic forward to more of your articles. half of the lamps will burn beyond Engineering Services in Rochester, Many thanks, Ken, for the infor- rated life. Minnesota. mation in your letter, and for your 2. Operation of a lamp on volt- Regarding your comments on lamp kind words. I'm familiar with the ages higher than that for which it was life, in the May db issue, I am won- lamp slide rule, and I appreciate your designed can significantly shorten life it. Mine comes in a Syl- dering if you have ever come across mentioning or cause immediate failure. Quartz - a Sylvania projection lamp slide rule. vania Audio Visual Projector Lamp line lamps, in particular, should not The rule I have has a copyright date Pocket Guide. This is a 3 -fold card be operated beyond 110 percent of of 1962. This provides the relation- containing information on Sylvania rated volts. ship of lamp voltage to socket voltage, audiovisual lamps, including the rated 3. With ordinary incandescent lamps, percentage watts to change in color wattage, the average life in hours, and life at reduced voltage is predictably temperature, and percentage light to the base type, and information on increased because burnout usually re- percentage life. So -if lamp voltage how to identify a defective lamp. sults from filament evaporation. With equals socket voltage, then you have SYLVANIA GUIDE Quartzline lamps, however, increased 100 percent watts, rated color temp., life cannot be accurately predicted While were on that subject, let's 100 percent light and 100 percent because life may be limited by fac- a from this informative life. Now drop socket voltage 5 volts quote just bit tors other than filament evaporation. and you have 93 percent watts, -55 guide. 4. Gradual blackening of the inside degrees in color temp., 85 percent Early failure: Lamp is clean and of the bulb during use is normal for light and a life of 185 percent - appears perfect in all respects except incandescent lamps. Quartzline lamps quite a change in lamp life! Should for broken filament. This lamp obvi- do not blacken, unless operated un- you run the lamp 5 volts above rated ously has not been burned any length der abnormal conditions. voltage, you then get 56 percent lamp of time, if at all. 5. Bulb blistering is normal with life, according to the rule. Leaker: A tiny leak in glass enve- some incandescent lamps toward the With regard to cooling the lamp lope has allowed air to enter the bulb. end of life. If a forced cooling system after turn off, comments to us by Milky, cloudy appearance identifies is used in the equipment, it should be General Electric indicated that this this condition." checked regularly to prevent block- cooling did not affect lamp life. How- Normal life failure: This lamp has age of the air stream. Even partial loss ever, vibration is critical to the lamp blistered after it was used for a num- of normal cooling can cause excessive at this time and the filament can be ber of hours. Another effect that can blistering or premature failure. damaged easily if the projector is result from normal life-a blackened 6. Change in apparent color temp- moved before the lamp has cooled. bridge. erature of Daylight Dichro PAR Lamp has obviously lamps when voltage is varied will be At a Bolex service session several served normal rated average life. the blacken- about twice the scale indication. years ago, the comment was made Note ing on top of bulb. If lamp was de- The second letter came from Jack that due to the inherent construction, signed to burn horizontally, the tell- B. Minkoff of Palo Alto, California. all heat filters possess a high internal tale blackening is on the side of the What is the best circuit for an in- stress and therefore have a fixed life. bulb, indicating a normal life. terface between a 16mm projector I once had one explode just lying on speaker (8 ohms) output (often fur- the bench with no one near it. General Electric also made a simi- nished by means of a r/4 in. phone You indicate that your next article lar rule. This one is a circular type jack to a remote speaker) and a will deal with 16mm projectors. May and gives the same information. It is microphone (150 ohms) or line level I make two pleas: called Stage /Studio Lamp Character- 600 ohms input into a mixer or mixer 1. Encourage istics Calculator for approximate effect projector users to amplifier? keep them clean, particularly the film of voltage variation on Quartzline® I am sure our readers have solved gate. Film is expensive and incandescent lamps. The one I and one care- this problem in different ways. We less user can damage and badly scratch have is dated Aug. 1971. would like to hear from any of you a film the first time through the On the reverse side, there are in- pro- who would like to share the results. jector. A small brush, with stiff bris- structions for using the circular slide Here is one way, maybe not the best, tles, can be held to the with rule and some interesting information: projector but quite good. a 3AG type fuse clip that can be For voltages not shown, multiply mounted on the projector if the orig- both lamp and socket voltage by 10 AAn inal manufacturer did not provide for or 100 to put them on the scale. For 250n this. Use the brush for cleaning the example, a 6 -volt lamp operated at 5 OUT film gate and other areas of the film volts is the same as a 60 volt lamp 27011 path. Take care not to scratch the operated at 50 volts. iSKll film pressure Note: Due to the variation between plate. UNBALANCED BALANCED 2. Equipment manufacturers specify individual lamp types, the results particular lubricants in various areas shown are close (but not exact) ap- Thanks to all those who have writ- for a reason! May I suggest that if proximations for any specific lamp. ten. We will continue to print cor- you don't know the manufacturer's Indicated values are reasonably reli- respondence as often as possible. IN

www.americanradiohistory.com A pick -up's eye view of a disc, illus- A small scratch made to look far worse 10 wavelengths of the 1.m. carrier, i.e., trating the very great depth of field and than it probably sounds. The deforma- each lasts for approximately 1/3000 false perspective which the scanning tion of the groove wall covers about of a second. (X100 and X500) electron microscope can be made to produce. (X160)

EDWARD HORN

In the CD -4 Groove

A general view at approximately 45 Metallurgy and microscopy reveal the tremendous degrees to the surface. The vertical detail which the CD -4 groove carries. and lateral shifts of the groove and the deviations of the f.m. signal superimposed on them can easily be seen. Although this record was new and apparently clean, dirt particles are very noticeable. (X100)

THE FINAL YEAR of one's degree of the Metallurgy and Material Sci- course at Cambridge University ence Department of Cambridge Uni- concentrates the mind wonderfully. It versity in preparing and observing is also alive with opportunities to inves- portions of CD -4 discs in a scanning tigate the unusual. My principal sub- electron microscope. ject is the science of materials, but a A section cut from the disc is ren- major hobby is audio. This combina- dered conductive by electrically evap- tion aroused curiosity about the de- orating a small particle of gold over mands made on the disc -recording it in a vacuum chamber. If well process by CD -4 techniques. judged, the film of metal which con- Examination of the record groove denses onto the sample can be only by optical microscopy reveals only a a few atoms in thickness. The pre- part of the picture. The obtainable pared specimen is then put into the depth of field has practical limitations. microscope, where, after evaporation, So I sought the help of D.G.D. Gray, it is scanned by a finely focused elec- tron beam. The intensity of low - energy secondary electrons emitted from the sample varies with the sur- High magnification of a single groove Edward Horn under- revealing faint parallel lines, probably is a third year face morphology. By means of an resulting from imperfections of the graduate, majoring in Material Science electron detector and associated cir- original cutting tool. The two rows of at St. John's College, Cambridge cuitry, an image of the surface is built debris visible on the "land" at the University, England. His father is up on a cathode ray tube, which is top of the groove walls are also of Geoffrey Horn, the well -known being scanned in synchronism with CV interest. (X1000) English hi -ft authority and reviewer. the beam inside the microscope.

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Low Distortion Oscillator Series 3 A continuously variable frequency laboratory oscillator with a range of 10Hz- 100kHz, having virtually zero Both taken looking along a groove at a telephoto lens. This exaggerates both distortion over the audio frequency few degrees to the surface, giving the the modulation of the groove and the same false impression of distance as a frequency deviations of the 1.m. carrier. band with a fast settling time. SPECIFICATIONS: Frequency range: 10Hz- 100kHz (4 bands) Output voltage: 10 volts r.m.s. max. Output source resistance: 150 ohms unbalanced (plus 150/600 balanced/ Controls permit movement of the peth, New York 11378. floating) sample within the evacuated cham- Output attenuation: 0 -100dB (eight, According to Eargle, the last six 10dB steps plus 0 -20dB variable) ber. One can select electrically the months have also seen considerable Output attenuation accuracy: 1% desired magnification to yield any interest in CD -4 cutting technology. Sine wave distortion; Less than 0.002% number of views on the screen -to Two significant improvements were 10Hz -10kHz (typically below noise be photographed as desired. Ade- shown to the recording world at this of measuring instrument) quate depth of field is obtained, but spring's Audio Engineering Society Square wave rise and fall time: 40/60 one has to be aware of the gross per- Convention in Los Angeles (May 13 n.secs. spective distortion which can take Monitor thru 16). output meter: Scaled 0 -3, 0 -10 place. and dBV. That includes the new Mark III Mains input: 110V/13,0V, 220V/240V The results indicate the tremen- cutting system developed jointly by Size: 17" (43cm) x 7" (18cm) high x dous detail carried in the CD -4 JVC, RCA and Matsushita in Japan. 8 %" (22cm) deep groove and maybe clear the need for The significant features of this new Price: 150 ohms unbalanced output: a playback cartridge capable of cop- cutting package are its low price (in $950.00. ing with this wealth of information. the $30,000 range) and the ease with 150/600 unbalanced /balanced floating which it can be interfaced with a stan- output: $1070.00. dard cutting system. The modulator Distortion Measuring Set FURTHER NOTES ON CD -4 design is a unique kind of modulated phase lock loop, exhibiting greater Series 3 We learn from John Eargle of JME linearity and dynamic range than its A sensitive instrument with high in- Associates that A & M Records has predecessors. put impedance for the measurement made a long -term commitment to In parallel with JVC, RCA Records of total harmonic distortion. De- CD -4 and intends to issue their quad - has developed its own modulator unit signed for speedy and accurate use. riphonic disc product only in the using the same phase lock -loop prin- Capable of measuring distortion CD-4 format. ciple. Both of these units underscore Increased software activity has been very clearly the fact that CD -4 cut- products down to 0.001 %. Direct evident from RCA and the WEA ting technology has indeed been sim- reading from calibrated meter scale. group as well, and the total U.S. CD- plified -and improved -and is well SPECIFICATIONS: 4 catalog has grown from 194 in within the budget of many recording Frequency range: 5Hz -50kHz (4 bands) June of 1974 to 258 by the end of companies and studios. Distortion range (f.s.d,): 0.01 % -100% December 1974. As of the first quar- Eargle also announces that the Or- (9 ranges) ter of 1975, the U.S. catalog increased tofon Company of Copenhagen, Den- Input voltage measurement range: 50mv -60V (3 ranges) by 22 items to a total of 280. mark, has made available its new DSS Input resistance: 47Kohms on all ranges On the consumer information level, 731 cutting head, especially designed High pass filter: 12dB /octave below a comprehensive 28 -page CD-4 Hand- for wide range, low crosstalk cutting 500Hz book has been developed and will be for CD-4. This new cutting head was Power requirement: 2 x PP9, included available to CD-4 dealers. Its aim is demonstrated at the recent Audio En- Size: 17" (43cm) x 7" (18cm) high x to explain to the interested consumer gineering Society Convention in Lon- 8 %" (22cm) deep what quad is all about -and especially don. Price: $770.00 how CD-4 differs from the matrix On the playback hardware side, AUDIONICS disc formats. Eargle concludes by reporting on con- Those wishing information concern- tinuing developments in cartridge de- 10035 NE Sandy Blvd. ing the CD-4 Handbook should con- sign by many companies, particularly Portland, Oregon 97220 tact Matsushita Electric Corporation Stanton and Empire. Both are adver- Authorized U.S. Sales Agency for of America, 1 Panasonic Way, Se- tising new models which optimize the Radford Laboratory Instruments caucus, New Jersey 07094, or JVC performance requirements of both America, Inc., 50 -35 56th Road, Mas- CD-4 and stereo. Circle 24 on Reader Service Card www.americanradiohistory.com MARTIN DICKSTEIN

The New York Experience

Sight, sound, vibrations, combine in an exciting hour of New York sensations.

ANY TIMES, when an exhibit is the sounds coming from various loca- M billed as multi- sensory, the ref- tions throughout the theater. erence is made to indicate that several In one scene, realism is enhanced different methods are utilized to inter- as image and sound tell the story of est the visitor. The term usually means Washington's crossing the Delaware, that two senses will be affected by the while real fog rolls into the theater presentation -sight and hearing. There from under the front screen. The is one show, however, that means scene envelops the audience as the what it says -literally -when it is de- people feel the fog. scribed as multi- sensory. It all results in a most exciting way for anyone to SUBWAYS really have a most unique and memor- In the modern city, no tale could able New York Experience. be told without mentioning the sub- New York Experience is located in way systems running under the streets. a specially built theater on the lower A partial view of the sophisticated It is a part of a way of life. As the level of the McGraw -Hill Building on equipment in the projection booth. presentation focuses on the under- the Avenue of the Americas at Rocke- ground behemoth, the noise and vibra- feller Center. It is one of only three tion are both heard and felt. During similar presentations in the world: one one sequence, a subway comes roar- in San Francisco, another in Hawaii, ing in and the audience again becomes and the third is the relatively new a part of the show. Not only is the show in New York. New York Ex- speaking just a mite loudly. Then the deafening sound heard in all its rea- perience is a Trans Lux /Bing Crosby theater starts to darken. It now be- lism, but low rumbling can actually enterprise produced by Electrovision comes apparent that some of the be felt-a sensation rather unique for Productions, Inc. The show opened in sounds are not within the theater it- audio /visual displays. A similar sen- 1973, and will he a permanent exhibit; self, but seem to be coming from out- sation occurs during a bombardment. we urge you not to miss it. The pres- side. You realize that this has been The rumbling sound can be heard, and entations are hourly and take just the beginning of the show itself which the blast can also be felt. under an hour to tell the story of New was sneaking into full presence so Among the visual and environ- York. carefully. The presentation had begun mental devices there are bubble ma- As you walk in, there is a replica before you were aware of it. Then chines, strobe lights, a car horn, real- of old New York, with a view of a the surprises begin. istic fire effects devices, special lights subway station and an elevated train The seven screens at the front light and an electronic organ controlled by that ran on 6th Ave., the former name up, sometimes displaying stills, then sound and many more, all part of a of the street you are on. The corner dissolving quickly at different speeds dazzling display. where you will walk has the old to form a vast panorama of New York stores, an umbrella- covered pushcart, harbor. The result is a spectacular WHAT MAKES IT WORK? and benches to sit on while relaxing view that seems to curve right around Planning this complex presentation and waiting for the theater show to the visitor. Now the side screens be- which runs almost without a hitch, begin. come active. They descend to cover 82 showings (7 days)a week, took a the walls or rise back out of view as tremendous amount of engineering SOUNDS IN THE DARK the history of New York unfolds from and design know-how. The entire show The theater is in semi -darkness as earliest days to the present, introduc- is automated -completely- except for the visitor enters. The screen is very ing a multitude of special effects. the technician pushing the start button wide and curved. As you look around, At one moment, an extremely bright each hour, and then making sure the the side walls appear quietly normal, thrust of lightning is seen, almost equipment, film, tape, slides, etc. are and the ceiling seems black with only blindingly. It starts overhead and all back at the start point about 50 a few identifiable lights. The seats strikes the Empire State Building. The minutes later. He also knows what to swivel all around and are very com- thunder accompanying the flash is do when problems arise and maintains fortable. In a few moments, as the momentary, but frighteningly close the system and the individual compo- audience is being seated, there are and realistic. As the images change nents. But once the show is under sounds of distinguishable voices, chil- both on the front screens and on the way, everything happens automatic- dren and adults. It sounds as though sides, the audience can swing the ally. a few of the people in the theater are seats easily to follow the action and With the start of the show, a 1/4-in. m

www.americanradiohistory.com tape cartridge (audience murmur) and sound. One is used for separate bass low the floor of the theater, a 26 -ft. a /t -in. magnetic tape begin to roll at reinforcement (which deserves spe- long unit was constructed with an 15 in. /sec. on one of two Scully tape cial mention) and the other is used to opening of 14 x 16 ft. It is used dur- decks. The 1/2-in. tape has four audio activate four 3 -color organs (by Mo- ing sound sequences such as cannon tracks (which were made in a reduc- bilcolor), located at the sides of the fire, but is basically most effective tion mix from an original 16 -track room. These lines are also under the during the sound of a subway "run- recording) and a cue track (between control of the computer and triggered ning" directly under the theater. tracks 2 and 3) which is only 0.03 at preset times. The speaker has a cut -off at 20 Hz. in. wide. It is this tiny stripe on which The 1/4 -in, tape cartridge (player At that frequency the ear is unable the rest of the show depends. It con- by International Tapetronics) is fed to hear, but the sound can be felt, as tains digital data which feed to the through 12 Atlas Sound WT -15 all - those in the audience know if the heart (or brains) of the system, a metal speakers with weatherproof subway has been one of their means model 990 Command Performer com- woofers, high efficiency drivers, and of transportation. The floor literally puter developed by Arion Corp. of crossover networks. These units are lo- vibrates, just as a subway platform Minneapolis, Minn., specifically for cated under the seats of the audience does. The bass speaker is cut in on this type of application. (In addition and are first heard at the very begin- cue from the computer almost a to San Francisco and Hawaii, they ning of the show when the sound of dozen times during the show (during also have their equipment installed at audience chatter sneaks in to the sur- the cannon shot for a period as short Disney World and in several countries prise of the visitors. These outdoor as about 0.1 second). of Europe including Russia, as well as units were chosen because of the real You might be wondering how a in Mexico, Canada, South America fog that comes rolling in from under show that runs just a little short of and Japan, plus some smaller projects the front screens during the show an hour can be handled at 15 in. /sec. at schools and universities.) blown in by four fog generators). Cone on one tape deck. It isn't. One of the The 4 -track sound passes through speakers could never last under this special automatic features of the sys- Arion preamplifiers, Crown DC 300A assault of moisture for very long. tem is that the second machine is amplifiers, and is distributed through The under -seat speakers are also used cued up and ready to go on a start JBL speakers located at the front of during the performance. cue from the computer. Once it gets the room. Dolby equalization was going, a cue on the second tape auto- used in the recording and playback BASS REINFORCEMENT matically stops the first machine. (This and four Sound Craftsman graphic The bass reinforcement does require first tape can then be recued to the equalizers are included in the repro- special mention, as the speaker is beginning and is ready again for the duction system to help with the con- unique. It is the largest in the world, next show.) The change-over time: touring of theater acoustics. There are and is, in fact, so large, that it had to less than 1/10 sec. also two mono -mixes of the 4 -track be built on the site. In the story be- PROJECTION The projection system is also unique. There are thirty slide projectors set up in the projection booth, using a total of about 2,500 slides. The units are controlled by dimmers and dis- solvers which can change images at `communication in every avant' five independent speeds (instant, 2, 4, 8, and 16 seconds). Every projector is controlled by its own fader, but even these are not just faders. Each is a complex unit involving a preci- sion analog computer with eleven op amplifiers. The double -layered front screen can handle seven side -by -side images. These are so accurately ad- justed that panoramic images across the entire spread can dissolve into another and look as if one dissolve ac- tion took place, but there actually are fourteen dissolve units operating at such a transition point. The three A.V.E. 16 -mm film pro- jectors are also unique. First, they were modified to permit interlock op- eration. These are run by selsyn mo- tors and are made to stop and start instantly. Since about half the time of the presentation is spent on 16mm film, the projectors use Xenon illumi- nation sources which are ozone -free (requiring no special ventilation) and no special cooling. The films have magnetic sound tracks and the pre- A division of Lumiere Productions amplifiers in the projectors were modi- CIe4r-Corle 759 Harrison Street, San Francisco, Ca. 94107 fied slightly to provide the best sound (. Podnble Inleaom Jyrlamr (415) 989 -1130 possible for the audio system. Another Circle 32 on Reader Service Card www.americanradiohistory.com internal modification was the addition puter and the sound is so smooth that of new aperture plates specially cut it is unlikely that the viewer will be for this show. aware of the 20 times the images change from slides to film and back. OTHER FEATURES In addition to starting tapes, cueing Some other modifications and pro- film projectors, cutting sound in and visions go into making the presenta- out, and setting off strobes or flashers, tion as smooth as it is. The projectors the computer, in its more than 3.000 are provided with special loop setters cues, is called upon to lower and raise which operate automatically, when the four sidewall screens, turn on rotating pull -down claw is retracted, at just wheels in front of slide projectors, cue 1/50 of a second separation from the super-8 projectors around the room, We take the wait pull -down mechanism. That ensures start star -projectors, turn on and off smooth running of the film in this con- lobsterscopes, turn rotating mirror re- out of erasing lots of tape stant start /stop operation. Another flectors above the audience, and trig- special feature is a magnetic foil stop ger more than 50 special effects de- on the film with just 4 in. of black be- vices in total, not counting the chas- tween film portions. No slippage can ing lights around the front screens, be tolerated here. etc. It is estimated that if all the spe- The projectors run at the normal cial effects were triggered to activate 24 frames per second, but usually the simultaneously, the total power drain New Model 70 cleanly erases any sound drums start to rotate when the would be more than 200 kilowatts. 7" reel, cartridge, or cassette in film is under way. In these units, the However, there are more than 120 one pass over the continuous sound drum is specially made to get relay circuits in the control system to belt. Your tapes will be as clean started with a automatic ten- those devices needed unique help activate only as new in 4 seconds. For audio, sion device so the sound head gets at any one time. video, and data tapes. going instantly with the start of the The thunder, lightning, fog, sub- projector. As another control func- way, cannon, and the vast special tion of the computer, the sound feed sound and visual effects make the New from the projectors is not cut into the York Experience a most novel multi - system until the projectors arc trig- sensory audio -visual experience -not gered to begin rolling, thus keeping to be missed by either visitor or New GARNERG INDUSTRIES the speakers off the line until the Yorker. Experience New York in less VeI,ra,wa 58501 sound is about to begin. The function- than one hour -comfortably, enter- ing of the projector motion, the corn- tainingly. Circle 25 on Reader Service Card

Why does RCA Records use the Amber Audio Spectrum Display?

RCA Records uses several Amber Audio Spectrum Displays in various applications in their Hollywood, Nashville and New York Amber model 4550 Audio lay studios. Larry Schnapf, Manager of Recording for RCA Records, explains some of the applications: "We use the 4550 in our Tape Mastering rooms both as a production tool and to spot potential problems. We often have to produce an equalized tape to match a domestic release to a foreign one. The spectrum display shows us where aad howu equalize ellto and using the two memories we can very y" pìobfeduplicatepotter the peak responding nature of the unit, wittrié'rnímory, captures transients that a VU meter ,1.uld normally miss. After considerable experience we have ermined what frequencies will cause high end distortion, 'tereo phase problems in ; Anibal EaEcnii discs and can recognize 1064 dlimin du I roblem and apply the subtle corrections necessary before mastering: MorrRtal e about the Audio Spectrum Display or H3E 1H4 stitclip..contact Amber for the name of a (514) 769 2739 dealer near you.

Circle 26 on Reader Service Card

www.americanradiohistory.com www.americanradiohistory.com TEAC

Multitrack Recording Equipment makes possible a kind of music that can't happen any other way. But you don't have to rent studio time. You can build a complete TEAC multi- track recording rig at home with the A-33405 4 -track multichannel recorder with Simul sync; the Model 2, a 6 -in, 4 -out mixer with filters, pan and multiple patch points; 2 -track mastering recorders from the A-33005 2T to the A-7300 2T; the ME- Series of electret condenser microphones, omnidirectional and cardioid; plus associated accessories... all the essential gear you need to make your inner musical perceptions audible reality. Getting the most from the technology to further the art is as much a matter of talent as tools. At TEAC, we make those tools with all your needs in mind, including the assumption that you have more talent than money. Because the art is always a struggle. But access to the technology doesn't have to be, and your TEAC retailer can demonstrate why. To find the one nearest you, just call (800) 447-4700. In Illinois, call (800) 322 -4400. We'll pay for the call. If you're just getting started with gear like this, we recommend the 3 hour taped course on Home Recording Techniques offered by the Recording Institute of America, New York, N.Y. Where art and technology interlace. TEAC The leader. Always has been. TEAC CORPORATION OF AMERICA: 77:13 Telegraph Road, Montebello, California 90640 TEA' 1975

(O

www.americanradiohistory.com o new productaservices

SUBMINIATURE MICROPHONE trolled by illuminated pushbuttons. features a thermal system using a dual Self- contained BF -3.5K offers full speed thermostatically controlled fan metering of all essential parameters, in a low turbulence environment for with remote control adjustment and quiet operation; thermal resistance metering terminations. Models for from transistor case to ambient is 0.2 either single- or three -phase primary degrees C/ W. Each output stage uses power operation are available. ten 150W single- diffused power trans- Mfr: McMartin istors, eliminating current limiting cir- Circle 51 on Reader Service Card cuits, with separate plug -in circuit modules utilized for each channel. A CASSETTE EDITING AND rocker -style circuit breaker is mounted REPAIR KIT on the front panel. The 15mHz i.c. The miniaturization possibilities of operational amplifier, similar to those ot.93ETrE used in analog computers, is electrets and transistors are combined t placed at ®WING &1213)1112 KIT the front end. a device in the Minimic to produce Mfr: BGW Systems measuring only .460 x .330 x .326 Price: $799.00. inches and weighing 0.75 oz. A slightly Circle 53 on Reader Service Card rectangular shape keeps it from roll- ing around, lessening clothing noises when it is used as a lavalier. The case FREQUENCY COUNTER is constructed of smooth, slick plas- tic so that clothing will glide over it. The electret is housed inside a sili- cone rubber boot, isolating it from Repairs may be made without dis- the case. Cable is constructed with a polyurathane outer sheath for strength turbing cassette components with this and flexibility, of pure copper braid kit, intended to fix breaks more than six from the As a preci- with 99 percent wrap. Inner con- inches hub. editing block, one side of the ductors are covered with flexible rub- sion block has a diagonal cutting guide at ber. Frequency response is ± 1dB 45 degrees for normal splicing and a 50 Hz 3kHz. volt- Six -digit portable model 5755A to Operates on d.c. butt cutting guide at 90 degrees for age or by means of a hearing aid bat- frequency counter capable of direct close editing. A five -inch channel counting to beyond 512mHz. The in- tery. holds the 150-mil tape. One groove strument weighs five pounds and mea- Mfr: Transound Company end of the pencil -like kit features a sures 31/4 x 8 x 73 inches. It operates Circle 50 on Reader Service Card hexagonally shaped spindle for manu- from a.c. lines, a d.c. supply or from ally driving the cassette tape via the an automobile cigarette lighter socket. 3500W F.M. TRANSMITTER hubs. Six adhesive -tipped polyester Laboratories, Inc. picks for retrieving tape ends lost in- Mfr: Ballantine side the cassette housing and six pieces Price: $745.00 of 150 -mil splicing tape, pre -cut to Circle 54 on Reader Service Card proper length, are contained inside the kit. Mfr: 3M L.E.D. METER Price: $3.10 Circle 52 on Reader Service Card

STEREO /MONO POWER AMPLIFIER

Model BF -3.5K 3,500 watt f.m. broadcast transmitter is driven in the IPA stage by 10 -watt B -910 exciter, This seven -point red l.e.d. meter using a pair of parallel connected type features -15 to +3 vu in 3dB steps. 4CX250B pentodes. A type 3CX3000/ Simplicity of construction keeps the A7 zero -bias triode is used in the unit rugged; there are no bearings. power amplifier stage operating in jewels or pivots. The meter features grounded -grid configuration; no grid mechanical inertia with no oversheet, bias or screen grid power supplies are A pushbutton bridging switch ef- and fast response peak detection with required, and no neutralization. P.A. fects the mono /stereo change on slow decay, for accuracy. The meter stage efficiency occurs from 2,000 to model 500D power amplifier, one of is supplied in vu or S with vertical or the maximum 3,500W output power a series of new models from this man- horizontal scale. Power required is 12- levels. Other features include auto- ufacturer, all conforming to the FTC 15 Vdc 30 milliamp. matic recycling, memory-type status trade regulation rule on amplifier Mfr: Pulse Dynamics Mfg. Corp. indication and an output reflecto- power- output specifications, carrying Price: $10.00 (NI meter. Start /stop functions are con- 4 -ohm FTC power ratings. The unit Circle 55 on Reader Service Card

www.americanradiohistory.com products & services (cont.) ELECTRONIC MUSIC One of a series of brief discussions SYNTHESIZER by Electro -Voice engineers

AUTO FLANGER

\ \\ 11%\ \ \\\\\\ Marketing Manager

With a I volt -per- octave control Professional and a linear keyboard output, the Products model 300 synthesizer allows any num- ber of oscillators, filters, and modules of other functions to be controlled The from a keyboard while tracking to- gether at a constant musical interval. INCREDIBLE Any external tuning control will change As an alternative to phasing, the with oscillator pitch by the same ELECTRET Auto Flanger offers a precise mathe- amount, regardless of keyboard posi- tion. The keyboard spans a full 5 -oc- matical relationship between the time Many tave engineering innoc,lti ons have the un- delay and the resulting comb filter re- range. It has exponential or line- fortunate habit of solving old problems only sponse, causing random program ma- ar portamento (glide) selection and to create new ones. The history of the con- terial (such as cymbals) to take on one -octave range tuning control with denser microphone is a case in point. musical tonality. The manufacturer instant zero return. Voice outputs are The introduction of the electret condenser claims that the device is capable of linear over the whole range. Fourteen output jacks mike, with its permanently charged dia- producing true flanging repeatably are supplied. The syn- phragm, eliminated the troublesome power and economically without the use of thesizer also contains an envelope gen- supply and problems caused by other prod- two tape decks or digital delay lines. erator with four independent controls uct complexities. Well -made electrets had the physical durability of dynamics -hut the first Through the use of an internal regu- over the dynamics of each note; a voltage filter with 16Hz -16,- generation of products failed in the area of lator, it may be implemented into any control a reliability. Performance specifications of early system and can be incorporated into 000Hz range; a voltage control ampli- electrets were severely deteriorated by heat a standard console or rack. fier with over 100dB of accurate gain and humidity, both in short -term, temporary control; balanced modulator and at- loss of operation, and more gradual, but ir- Mfr: MXR Innovations reversible, long -term deterioration. Price: $285.00 tenuators; voltage control oscillator; sample /hold, clock, noise generator; Circle 58 on Reader Service Card Now, with the introduction of a new genera- dual mixer; dual LFO, lag, inverter; tion of professional electret microphones. case and back plane connectors; power such as the Electro -Voice C515 and C085, CABLE FAULT TESTER supply. The elements may be pur- the cycle of problem and solution finally chased separately. seems broken. Mfr: Aries, Inc. These new Electro -Voice electrets are the re- Price: Kit: $895.00 sults of exhaustive research into electret dia- Wired: $1,500.00 phragm materials and charging techniques; research Circle 60 on Reader Service Card that led E -V to develop a combina- tion of a unique fluorocarbon material and CABLE F`AULT TESTER a proprietary charging process that produced -OIrN- greater PARAMETRIC EQUALIZER charge stability and better heat/hu- WMCT.\%// '0 midity resistance than had been possible in OJ : any previously marketed electret condenser -$1104 1- mike. Nmmc ula.own 4 I The benefits of E -V's new electrets were more apparent after I took the microphones Compact battery operated MCT-4 with me as a part of our field testing under cable tester will simultaneously check "worst case" conditions. Even after being left in the trunk of a parked car in as Vegas all conductors in three and four pin (where temperatures reached 180 °) for six "Cannon" type connectors, two and This vari -band equalizer has five si- hours, and exposed to the tropical humidity three circuit 1/4-in. phone plugs, as multaneous operational sections. Each of Florida and Hawaii, E -V's electrets showed well as RCA phono plugs. An l.e.d. section has ± 15 dB of boost or cut, no measurable charge degradation. matrix displays the i.c. operated logic bandwidth control from 16dB /oct. to circuit. The tester is designed to con- 2dB /oct., bandcenter control in /out sider resistance greater than 500 ohms switch and red indicator I.e.d. for fast For the ear with a brain. as an open, and less than 500 ohms comparison of any section or all sec- Electro- Voice, Inc. A GULTON Company as a Long low impedance micro- tions simultaneously. fre- short. Bandcenter Dept. 853 BD, 686 Cecil Street phone cables may be tested under quency sweep ranges for the five sec- Buchanan, Michigan 49107 conditions similar to their operating tions are 20- 100Hz, 100-600Hz, 600 - conditions. The unit scans for all pos- 3kHz, 3k -6kHz, and 6k -20 kHz. All sible open and short conditions over circuitry is operational amplified and 400 times a second. uses no transformers or inductors. Mfr: Crossroads Audio Mir: Multi -Track Saketerokbr: Price: $89.95 Price: $450.00 A SUBSIDIARY OF GULTON INDUSTRIES. INC. Circle 59 on Reader Service Card Circle 61 on Reader Service Card Circle 11 on Reader Service Card www.americanradiohistory.com new products & services (cont.) What POWER AMPLIFIER would S: you °woo . et expect This high -power rack -mountable amplifier is available in two models. Model SR105A provides both direct- coupled speaker output, 200 watt do? - IMA rms and an to continuous transformer-cou Perform SMPTE intermodulation analyses pled 150 watt rms constant voltage quickly and easily, even in the millivolt range? 70 -volt output. Similar model SR105B Measure amplifier noise? permits direct speaker coupling only. Measure transistor noise? The amplifiers are capable of deliver- Evaluate magnetic tape drop -out? The Crown IMA does ing 200 watts rms to a four -ohm load all of it. Internal inter - Test and may be interconnected with addi- oscillator amplitude stability? modulation distortion Measure tape recording distortion? tional units to provide the greater is less than 0.005 %. sound power required by especially Evaluate phono stylus wear and tracking? Write us for more large coverage requirements. Direct - Test electromechanical transducers complete information for intermodulation? and application notes. coupled frequency response is flat, 20 to 20,000 Hz, ± 1.5 dB. The amplifiers are protected against short or open circuit loads and can operate at full power at ambient temperatures up to crownlnTErnarionaL 42 degrees C. without derating. \AKA ROAD ELKHART, INDIANA 46514 219.294.5571 Mf r: Shure Bros, Inc. Circle 33 on Reader Service Card Price: SR105A: $348.00 SR105B: $321.00 Circle 56 on Reader Service Card

DIGITAL AUTOMATION SYSTEM

Digimation series 2000, a complete digital automation system for a.m., THE NAME AND THE PRODUCT THAT f.m., catv, sca, and other audio ap- , plications, features state -of- the sol- -art SETS THE id state audio switching and built -in STANDARD 25 Hz tone sensing, eliminating the need for external sensing equipment. FOR P.A. EQUIPMENT Up to eight sources of reel -to -reel i Whatever your PA needs, from a small office to large auditorium, % or cart machines may be connected with amplifiers in every power range, including mobile, 1 in any configuration. The 16 event Precision Electronics delivers the product and value ... including an memory is impervious to power fail- entire line of accessories. Get all the facts, without obligation, on the ures. The system also contains ad- "right sound" for your needs. Complete and mail this coupon today. justable silence sensing, a priority in- terrupt function, vu meters, internal % NAME J monitor amp and speakers (switch - COMPANY able to PGM, CUE, and AUX), and e bridging unbalanced inputs with 600 CITY - STATE ZIP e ohm balanced outputs. iie Mfr: Audio/ Video Products Mail to: PRECISION ELECTRONICS, INC. O. Price: Stereo: $1,950 9101 King St.. Franklin Park, Mono: $1,550 (V Pe" =ss N .MIa 601131WM NM OaI.- ' Circle 57 on Reader Service Card Circle 34 on Reader Service Card www.americanradiohistory.com Powerful alternative.

SAE 2500 Professional Dual -Channel Power Amplifier

When you compare power amplifiers, you have to look at the Features. Feedback level controls assure a constant input im- hard facts. The SAE 2500 Professional Dual- Channel Power pedance of 50k Ohms and reduce the noise figure to more Amplifier has them -top power, specifications, reliability and than 100dB below rated output in all positions. Loudspeaker features that make it the most "powerful alternative." protection relay- activated circuit automatically disconnects speakers in case ±DC outputs. Plus, direct power reading Power. 450 Watts RMS of per channel, both channels driven VU meters and forced air cooling. into 4 Ohms from 20Hz to 20 kHz at no more than 0.1% total weighs harmonic distortion. Or, 300 Watts RMS per channel, both The SAE 2500 Professional Power Amplifier only 58 lbs. making it practical for portable sound reinforcement, channels driven into 8 Ohms from 20Hz to 20 kHz at no more address, communications and recording applications. than 0.05% total harmonic distortion.* Plus, a new, smaller public wide -channel power transformer coupled to 4 computer - Specifications. grade capacitors for a power supply that varies no more than 10% from no load to full load. (For extra protection, there IM Distortion from 250mW to rated are relay and thermal cut -out devices.) power at 4 or 8 Ohms with any 2 mixed frequencies between 20Hz and 2500 INTERMODULATION DISTORTION @ 8 OHMS, FULL POWER 49V RMS 20kHz at 4/1 voltage ratio 0 05 Max BOTH CHANNELS DRIVEN Frequency Response at rated power t0.25dB. 20Hz to 20kHz IM Noise Greater than 100dB 1...... below rated power Transient Response of any Square Wave 2.5p sec rise and tall time Slew Rate 40 V sec O1 N Dimensions Front panel 19'W x 7'H Chassis 15 excluding handles controls 30mal 100mW 300mW 1W 3W 10W 30W 100W 300W and connections 'These specifications comply with FTC requirements for power amplifiers 2500 TOTAL HARMONIC DISTORT ON 8 OHMS, FULL POWER 49V RMS BOTH CHANNELS DRIVEN %THD .04 The professional alternative. .03 .02 .01 .00 20Hz 200Hz 2KHz 20KHz

Reliability. The SAE 2500 gives you high current capability Scientific Audio Electronics, Inc. DB/8/5 with Parallel- Series -Output Circuitry (P50)- without loss of P.O. Box 60271 wide power bandwidth, low leakage current or super -high Terminal Annex slew rate. Sixteen triple -diffused output transistors have an Los Angeles. California 000o0 electrical and thermal SOA 50% higher than maximum design )'lease send me the reasons (including available literature) why the SAE 2500 requirements for reliable high demand capability. This con- Professional Dual -Channel Power Amplifier is the "Powerful Alternative." figuration can handle anything from continuous full signals Name to highly reactive surge loads -all day long without failure or Address overheating. Dual relay disconnect circuits and plug -in board design further assure reliable performance. City State 7ip Circle 36 on Reader Service Card www.americanradiohistory.com Rack em up.

For studio, broadcasting, recording, or public- address, Shure audio control components offer more features and more performance, dollar for dollar, than similar equipment. And -just as important -Shure audio components are easier to work with. Their compact size and versatility equip them for an extremely wide variety of audio control applications -and built -in input - output flexibility means quick set -up anywhere. For a permanent installation or a component system that can be adapted to meet any need, Shure has the right combination. To obtain a copy of the Shure catalog, see your dealer or write: Shure Brothers Inc. 222 Hartrey Ave., Evanston, IL 60204 , In Canada: A. C. Simmonds & Sons Limited SHURE Ñ Manufacturers of high fidelity components, microphones, sound systems and related circuitry. Circle 35 on Reader Service Card www.americanradiohistory.com ROBERT C. EHLE

Operations of Moog Synthesizer Modules And Components

Familiarity with the functions of synthesizer modules enables the user to select a custom planned instrument.

N TEACHING the operation of synthesizers in several algebraic sum of all of the inputs presented to it. There schools, I have found that a desirable first step is to are five such inputs: the three jacks marked control volt- take each module in the synthesizer and describe its age and the two controls marked fixed control voltage. The operation. Thereafter, the different interconnections two controls are a range switch and a vernier, both of can be studied after the student has a working knowledge which are marked off in volts. The summing amplifier of each module. takes the algebraic sum (accounting for the sign and the Here we describe the typical modules found in a magnitude of each component) and then generates a cur- medium -sized synthesizer, in this case, one manufactured rent proportionate to the sum. The current is a voltage - by the R. A. Moog company, although other brands are controlled current. very similar. The modules are as follows: oscillators, mix- It is this voltage -controlled current that is actually fed ers, keyboard, voltage -controlled amplifier, envelope gen- to the model 901 -B oscillator. The oscillator contains a erator, filters, ring modulator, envelope follower, and capacitor which stores this current as it is fed in. As the sequencer. The last three modules are extras in the Moog capacitor fills or charges, the level of electrons or charge synthesizer. The ring modulator and the sequencer are increases in the capacitor. A level detector senses when usually mounted in separate cases. They are included in the capacitor is full and rapidly discharges the capacitor. other manufacturer's synthesizer models, however, and are This slow charge and rapid discharge produces the saw - basic components in electronic music procedure. For that tooth wave, the basic waveform in the Moog oscillator. reason they are included here. The switch on the panel of the 901 -B selects one of six A purchaser of a modular synthesizer may select any different capacitors, thus selecting one of six different set of modules he prefers and thus have a custom synthe- charge rates. The knob beneath the switch is a vernier sizer from "off- the -shelf' components. Most customers for that control. prefer to take the advice of experts and accept a standard The other three waveforms (sin, triangular and pulse complement of modules in a specially built cabinet. Such waves) are generated by waveform modifying circuitry a standard complement may be purchased by number from the basic sawtooth waveform. Thus all waves have from most manufacturers exactly the same frequency and are in phase. They may be used simultaneously for performing synchronized con- THE MOOG OSCILLATORS trol functions. The Moog model 901 -A oscillator controller is, in ef- Different models of synthesizers have slightly different fect, an amplifier with the special capability of taking the oscillators. The difference is more in appearance than operation. In the Synthesizer 2, the oscillator is a one -piece unit. Robert C. Ehle teaches at the School of Music, In the Synthesizer 1, however, the oscillator appears to be University of Northern Colorado, Greeley, Colorado constructed from three modules. That is not actually the

www.americanradiohistory.com CHANNELI LEVEL INPUT MIXING CONTROLS CHANNEL A OUTPUT

SIN WAVEFORM SQUARE WAVEFORM SAWTOOTH WAVEFORM

CHANNEL B OUTPUT

CHANNEL 2 EAR PHONES INPUT LEVEL

EAR PHONES 8 OHM OUTPUT

TRIANGULAR WAVEFORM NARROW PULSE WAVEFORM WHITE NOISE Figure 2. Block diagram of two -channel mixer in Moog synthesizer.

Figure 1. Examples of various waveforms as displayed on an oscilloscope.

than true harmonics. For that reason, the piano cannot be synthesized by subtractive synthesis, but only by additive case, as the modules are internally wired together and are synthesis. inseparable. Thus, the 901 -A oscillator controller, the The three terms -partial, overtone, and harmonic -have 901 -B oscillator and the 901 -C output stage are all parts different but related meanings, and their differences are of one oscillator and may not be separated. Note that only worth noting. To sum up, any component of a complex the left oscillator has an output stage; the right oscillator sound is a partial. Partials having small whole number has none. ratios are overtones, and partials generated by the same The function of the oscillator controller is to provide string or pipe are overtones (a generic term). a voltage -controlled characteristic to a semiconductor os- cillator which would normally be sensitive to changes in THE MIXERS current rather than voltage. Signal connections between The Moog model 982 mixer is necessary for nearly all the oscillator controller and the oscillator are internally work done with the synthesizer. FIGURE 2 illustrates a made. The function of the output stage is to provide block diagram of model 982. Note that the two input an amplitude control, a switch selectable set of waveforms, controls act as partners between the two inputs. The tone and a pair of complementary outputs. Thus the output sig- controls and level controls apply only to their particular nals from the 901 -C are identical to those from the 901 -B channel marked A or B. Also, the earphone jacks are with these exceptions. stereo and have inputs from both channels. That permits The four waveforms made available are the sin wave, the synthesizer to be used as a self -contained instrument the square wave, the triangular wave, and the sawtooth with a pair of earphones. The center of the tone controls wave. The square wave may be converted into a variable (twelve o'clock) is the flat position. width pulse wave with the pulse -width control on the Other types of mixers will be useful in electronic 901 -A. FIGURE 1 shows various waveforms found in the music. One of the most useful is the panner. The panner synthesizer, as displayed on an oscilloscope. An oscillo- has special controls allowing one output to be reduced scope is an ideal tool for presenting a visual picture of the while another is increased. That may be used to produce characteristics of electronic music. The drawings illustrate the effect of moving sounds when the two outputs feed the various waveforms and illustrate the concepts of variable - two channels of a stereo sound system. width pulses. Simple mixers may be either "wet" or "dry," meaning powered or unpowered. Powered mixers may provide am- OSCILLATOR TERMINOLOGY plification and absolute independence of control of one Various names are often used for the component part channel from the others. They have no cross -coupling. of the different waveforms. When the complex but repe- Unpowered mixers may only provide a limited amount of titive wave is analyzed by means of Fourier techniques, the isolation, and turning a control on one input will have results are a series of harmonically related frequencies some effect on the others. Unpowered mixers may pro- called harmonics. The fundamental frequency (the lowest vide only loss and no amplification. They are, however, frequency) is the first harmonic. The sin wave contains inexpensive. The less expensive powered mixers may, in only the fundamental, while the square wave and the fact, be less desirable because they introduce noise or hum. triangular waves contain only odd -numbered harmonics (1, 3, 5, 7, 9, etc.) and the sawtooth wave contains both THE KEYBOARD -PITCH CONTROL odd- and even -numbered harmonics. The Moog keyboard contains two types of control out- The components of a wave that are present are called puts, one operated by the keyboard and the other by the partials; thus, the second harmonic is the second partial internally triggered envelope generators. Here we discuss of a triangular wave, but the third harmonic is the sec- the keyboard-controlled pitch voltage outputs. ond partial of a square wave (because the second har- This voltage output (actually two outputs in parallel, monic is absent). But partials do not have to be harmonic having exactly the same output signal) has a range of zero (in which case the wave is not periodic and cannot be to 6 volts. Normally it is used to control the voltage -con- analyzed by Fourier analysis). For example, the piano trolled oscillator but may control any voltage -controlled tone contains frequencies which are not harmonic; these device with this voltage range. are called partials but not harmonics. They are overtones, The controls affecting this device are the scale, range, however, because they are generated by subdivisions of the hold and portamento. These labels apply to the effect same string. They are non -harmonic, due to string stiff- achieved when controlling the voltage -controlled oscil- ness and the end effect, which makes the overtones higher lator and indicate the specific parameter of the sound thus

www.americanradiohistory.com controlled. Thus, scale determines the scale produced; may be synthesized, but is never heard in nature. Thus range, its tessitura; portamento, the connection between it makes an interesting resource for original music. pitches; hold, the effect when all keys are released (with The voltage-controlled amplier may also be used as an the switch on. The internal circuitry remembers the last key amplitude modulator. In this type of arrangement, one depressed and continues to produce that control voltage). signal feeds the signal input while the other feeds the con- Of course, these controls have related effects when the trol input. The amount of intermodulation can be con- pitch -control voltage is used to control, for example, the trolled by the setting of the fixed- control voltage which voltage- controlled amplifier. That is possible since all Moog sets the operating point on the amplifier's characteristic modules have exactly the same control voltage range and curve. The voltage -controlled amplifier, when used as an are interchangeable in this respect. amplitude modulator, produces more harmonic distortion By inserting a resistor, used as a voltage divider, be- than a well- adjusted ring modulator and is, therefore, less tween the output of the pitch -control section and the volt- desirable for live- concert modulation of voices and instru- age- controlled module, the range may be reduced farther ments than that of instruments alone. than the internal range control allows. When controlling the voltage -controlled oscillator, this permits "micro- tonal" THE KEYBOARD -ENVELOPE GENERATION scales and other unusual effects. The basic Moog keyboard contains two envelope genera- tors which are internally connected to the keys of the THE VOLTAGE -CONTROLLED AMPLIFIER keyboard. Thus, every key triggers both envelope genera- The Moog voltage -controlled amplifier is a singly bal- tors in an identical fashion. anced (control input only) modulator with a resemblance Interconnections from the envelope generators is by to the ring modulator to be described later. The difference means of two patch cords, one for each envelope genera- is in the specific circuitry used to balance both inputs in tor. The output control voltages again have a range of zero the ring modulator. to 6 volts. They may be used to control any of the Moog Normal operation involves connecting the voltage-con- voltage -controlled units. Normal use is to connect them to trolled amplifier to the envelope- control voltage output the two voltage -controlled amplifiers for generation of ac- from the keyboard, thus using the voltage- controlled am- tual envelope control. Thus the controls are labeled for plifier for envelope generation triggered by the keys on the this application. The four controls on either envelope keyboard. For this type of operation, the fixed -control generator are labeled attack speed, attack height, decay voltage control on the amplifier is set to zero. The expo- time and sustain level. When the generator is used to con- nential /linear switch may be set either way, although an trol an envelope with a voltage- controlled amplifier these exponential curve duplicates the type of envelope pro- are the actual parameters controlled. duced by an acoustical instrument such as a piano. (Such Of course, as with other Moog voltage -controlling mod- an instrument seems to have a linear decay due to the ules, the generator may be used to control the oscillator compensation by the ear which has a logarithmic char- or the voltage -controlled filter as well. In these cases an acteristic.) A linear decay is one of those sounds which analogous effect is produced by the controls, which may

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IITHE LONDON COMPANY / 811 SHARON DRIVE / CLEVELAND, OHIO 44145 / (216) 871 -8900 VN Circle 27 on Reader Service Card www.americanradiohistory.com technique may be used to produce very slow attack times 100% on the simple envelope generator synthesizers.

THE FILTERS EXPONENTIAL CHARGE OF VOLTAGE Two types of filters are employed in the Moog synthe- ACROSS A CAPACITOR sizers. These are fixed band -pass filters and variable volt- age- controlled filters. The voltage -controlled filters are of 63% R C EOUALS two types, low -pass and high -pass. When used with an TIME CONSTANT OF CIRCUIT auxiliary coupler, the combination of a low -pass and a high -pass filter results in a voltage -controlled band -pass LINEAR CHARACTERISTIC filter or a voltage -controlled notch filter, depending on CURVE how they are connected. Fixed filters are usually supplied in banks which may be specified as quarter- octave, third -octave or half- octave,

LOGARITHMIC depending on the sharpness of the filter band character- CHARACTERISTIC OF THE EAR istic. Narrower band filters require more units to cover the same total range. Third- octave filters require three per octave, half -octave filters two per octave, and so on. Voltage -controlled filters are usually provided with a regeneration control which is used to regulate feedback Figure 3. Graphic representation of exponential versus linear characteristic curve. around the filter. When turned up, the regeneration con- verts the filter into a resonant filter, similar to the acousti- cal formant filter. That is useful for musical coloration. Note that the resonance occurs at the point of maximum not be the exact effect described by the label of the amplification or minimum filtering. control. The Moog voltage -controlled filters have the same con- The larger Moog synthesizers also contain independent trol voltage range as all the other Moog modules and may envelope generators with a somewhat wider variety of be controlled from all the common control devices. They control. They have a continuously variable attack time may also be modulated, producing spectrum modulation. rather than the two -position switch and they have a trig- ger input. THE BODE -MOOG RING MODULATOR An interesting variation in envelope control is to drive An instrument designed by Harald Bode and manufac- one signal input of the vca with one envelope generator tured by the R. A. Moog Co. is the multiplier -type ring and the control input with another. The resulting envelope modulator with squelch. Producing a much lower distor- will be the difference between the two envelopes. This tion output than equivalent circuits set up on the Moog synthesizer, this unit is ideal for live performance and REMOTE BROADCASTING produces a particularly attractive and musical output. The inputs may be any combination of audio signals. If one ©: 1=1, of the two is a "live" acoustical instrument, and one an :3+ s r electronic sound source, attractive variants on the acousti- .T,â?©G 0, to; cal signal result. The technique is desirable for use in real - time electronic music performances. The multiplier -type ring modulator generates very small REMOTE SITE CONSOLE amounts of harmonic and intermodulation distortion (other Use standard telephone line than the desired sum and difference). Thus, when two sin Direct distance dialing waveforms are presented to the two inputs, the output is Set up and check out in minutes also a pair of sin waves, the sum and the difference of the two inputs. Other ring modulators may generate harmonics High and low end frequency compensation with automatic level control option of the modulation products as well as products of the Lost line auto hang up option harmonics of the input signals. These roughen the sound Auto pick up on redial option quality of the output and make it much less attractive Up to 6 microphone inputs with level control option, to the listener. 4 headphone outputs with level control The reader is referred to the Electronic Music Review, Output matched for standard telephone line or loop vol. 1, no. 1, for detailed discussion of techniques that with level control, VU meter, built -in telephone may be performed with the ring modulator. Some of line coupler and output for PA amplifier these techniques will be repeated here for convenience. AC /DC with battery test meter If the two signal inputs are complex waves, such as Built -in telephone dial square or sawtooth waves, having an infinite series of Options in addition to those noted Include: partials, the resultants will be two infinite series of par- carrying case, microphones, headsets, tials, one the sum series and the other formed by the dif- test tone generator, aux inputs, phono ference. cartridge input and three pin connectors If one input is a band of white noise, and the other a sin wave, the band of white noise will appear in the out- put but twice as wide, or in two segments formed by the sums and the differences, respectively. If the sin wave is made to sweep, the white noise in the output will also sweep, producing the effect of "howling wind." Sounds picked up by a microphone may be ring -modu- STATION END CONSOLE lated with themselves if the overtones are filtered from PULSE DYNAMICS MANUFACTURING CORP. one input and the entire spectrum is presented to the Box 355, Fulton & Depot Sts., Colchester, III. 62326 (309) 776-4544, 776 -4575 other input. Circle 28 on Reader Service Card www.americanradiohistory.com trol voltages to the oscillator, and a series of input and A NOTE ON THE output jacks for each count position. These allow any BODE RING MODULATOR position to control or to be controlled by an external signal. Due to the advances of tech- nology and more recent devel- BIBLIOGRAPHY opments a new instrument has evolved from the Bode Ring Ehle, Robert C.; Techniques for the Synthesis of Electronic Modulator, manufactured by Music, in North Texas State University Electronic Music Corn- Moog, referred to in this article. position Lab Manual, Denton, Texas 1966. It is the Bode Frequency Shifter. Howe, Hubert; Buchla Electronic Music System User's Manual, CBS Musical Instruments, Columbia Broadcasting System, Inc. which comes in a Bode version 1300 E. Valencia, Fullerton, California 92631. and as a Moog module. In con- trast to the ring modulator. Mathews, Max V.; The Techno logy of Computer Music, The M.I.T. Press, Cambridge, Mass. 1969. which changes two sine waves with the frequencies f, and f_ Moog, Robert A.; Electronic Music Composition- Performance Equipment Catalog, R. A. Moog Co., Trumansburg, N.Y. into the combination of f, -° f_ 14886. and f, - f., at the output, the 'bid; Instruction Manuals for Synthesizers, R. A. Moog Co., frequency shifter is capable of Trumansburg, N.Y. 14886 (supplied with synthesizer units). separately producing the side - Specifications on the Tonus (ARP) Synthesizer; Tonus (ARP), hands f, f, and f, f., on - Inc., 45 Kenneth Street, Newton Highlands, Mass. 02161. two individual outputs. A mixer Specifications on the Buchla Synthesizer; CBS Musical Instru- combines both sidehands for a ments, Columbia Broadcasting System, Inc., 1300 E. Valencia, In the center posi- third output. Fullerton, California 92631. tion of the mixer control the Specifications on the Electro Comp Synthesizers; Electronic signal of this output equals that Music Laboratory, Inc., P.O. Box 1334, Hartford, Conn. 06101. of a ring modulator. Specifications on the Moog Synthesizer. R. A. Moog Co., Tm- mansburg, N.Y. 14886. Specifications on the Putney Synthesizer; Ionic Industries In- corporated, 128 James Street, Morristown, N.J. 07960. Von Foerster, Heinz and James Beauchamp; Music by Com- puter, John Wiley and Sons, Inc., N.Y. The ring modulator produces a particularly attractive Electronic Music Review, Volume 1, number 1. Various au- tremolo effect when connected in the same manner as thors. Discussions of applications of ring modulation. standard tremolo or vibrato on an amplitude modulator. If the unmodulated signal is reproduced through one loud- speaker and the modulated signal through another, the result is a sort of amplitude -phase modulation in space which is very attractive. Any sound may be transposed (up and down simul- taneously) by modulation by a sin wave. Up transposition is produced by the sum tones and down transposition by take advantage the difference tones. Dont settle for just any professional power amplifier. The Bode -Moog ring modulator is also available in dual Take advantage of the BOSE 1800. units for stereo operation and other techniques. Advantages like high power, ruggedness, reliability. serviceability. LED power indicators, and a full 5 -year VOLTAGE -CONTROLLED SEQUENCER warranty. The Moog sequencer is voltage- controlled and voltage - The 1800 gives performers the advantage by providing controlling. This means that it is useful only with voltage- them with all the power they need to handle the dy- controlled modules of the type normally supplied with the namics of their music. Moog synthesizers. The range of output voltages is 0 -2. BOSE 1800 pro power amp: designed to be taken ad- vantage of. 0 -4, or 0 -8, selectable by a switch which provides a de- gree of control but also a slight incompatibility with the '-Please send intormahon on the BOSE 1800 to 1 0 -6 volt range of the Moog modules. Name _ _ The Moog sequencer is built from digital computer com- I Address I Cdv State /Z,o - ponents and is based on a binary counter. For this reason . it has eight stages (23). A three -level binary counter BOSF The Mountain. Framingham MA D1701 617 879:330 Or ut DP J counts to eight and then resets' and begins counting over again. This is the procedure used. The pulses actually _A7vsF1BOo counted come from a standard voltage -controlled oscilla- tor. The repetition rate of these pulses may be controlled by varying the control voltage. Thus, the counting speed may be controlled. The three -level counter is decoded using computer logic to produce one line out of eight with a signal on it. This signal line corresponds to the count on the counter (and the light on the panel). The signal line activates one of eight switches which applies the control voltage to the out- put. There are actually three switches per count, one for each of three outputs. Each output has a separate control for each of the eight counts. Other features include skip and stop switches, a switch to apply the third row of con-

www.americanradiohistory.com DAVID COPE

A Realistic View Of Electronic Music

Development of fully realized electronic music depends on mutual understanding between composers and technicians. A composer tells how to dissolve existing confusions.

N A SENSE, all sounds emanating from a loudspeaker you have teams working together. You must have corn- represent electronic music because they are the rea- posers and technicians alike. Four things, really: composer, lization of electric currents projected through (or technician, good equipment and a company or factory with with) air by way of paper cone vibrations. More money to back the operation as well as performers in specifically, however, electronic music has come to mean some cases, and as long as these elements cannot work those sounds which originate from audio oscillators or gen- together you will have small laboratories without any out- erators and are altered by processes of filtering, envelope standing results." construction, etc. This not -so -new art, dating back to Del - The many problems become magnified when trying to aborde's Electronic Harpsichord in 1761, has suddenly teach electronic music to musicians and /or electronic music (since about 1951) become a serious art form, a popular to scientists. Synthesizers such as that shown in FIG. 1 rock device, a profound contributor to the commercial are typical of manufacturers' attempts at making sound music scene. Over 30 percent of TV commercials employ synthesis a possibility for one "Renaissance" man to cre- either complete or partial electronic sources, according to ate a great work of art. Piano -type keyboards abound (and a study done by the author two years ago. It's also a with them the ten -finger limitations of piano music which guaranteed Pavlov scare technique in the motion picture electronic music is, or should be, able to avoid). Fre- industry (current example being The Exorcist). quency switches containing reference points in organ stop We are not concerned here with the history, aesthetics lengths (8 ft., 4 ft., etc. rather than Hz) are at every or current uses of electronic music, but rather, the dis- oscillator; numerous other musical reference points no tinctly unique problems of the interdisciplinary synthesis more than hint at the ultimate use of the equipment. of music and science. In a recent interview with Pierre On the other hand, a host of oscilloscope functions, Boulez, conductor of the New York Philharmonic Or- digital sequencers, sample hold techniques and waveform chestra, I became more acutely aware of these problems. indicators contrast the musical terminology with often Boulez offered the following observations: highly technical and strangely abbreviated scientific jargon. "I think that you cannot do good work in this area until To say the least, teaching the synthesizer and its manifold functions to any group of specialists requires a remark- able blend of vocabularies, leaving most students with the impression that only a madman would attempt an hon- est association with this combination of gear and gadgetry. David Cope is a distinguished composer whose works To date, most of the writing about this subject has been have been performed by major orchestras. He is at in music journals or textbooks edging around electronics, present resident composer and director of the Electronic acoustics, and engineering with variable amounts of suc- rai Music Laboratory of Miami University, in Oxford, Ohio. cess. The composers, teachers and serious practitioners of

www.americanradiohistory.com electronic music have had to be content to subscribe to music journals as well as journals such as db and others in the scientific fields of acoustics, electronics and physics. The intent here is to acquaint the sound engineer with the incredible problems the serious composer of electronic music faces. By doing so, we hope that more literature will appear offering solutions to some of these problems. eve THE QUALITY MIXER UNFAMILIAR GROUND Through necessity, the composer must search an initially unknown subject, electronics, to gain even a bare insight ON THE ROCKS into his raw material (the instrument). And the electronics engineer must grope through the more personal, yet still highly technical skills of unfamiliar musical material. For the most part, as Boulez has pointed out, neither combi- nation has yet produced outstanding results. Going ahead in one's own speciality without anything but a bare knowledge of the other fields involved has some- times proved fatal in the end result. We find the creative process so ego- demanding that, as Stockhausen has re- marked, "It is necessary to constantly switch personnel so as not to invoke daily fistfights." Half the time, the spe- cialist is attempting solutions without knowing the prob- lems encountered in the other discipline. (A complete studio was once destroyed by a composer turning all pots on full to hear his sound, unaware that his product was sub -audio). One can easily uncover a problem and call for an answer. Proposing a concrete solution is another matter. OR After having worked in electronic studios for over seven years and taught college courses for a number of years, STRAIGHT I've come up with a set of priorities possibly of value to the sound engineer, most certainly of value to the elec- tronic music composer. My priorities are not complete, UP they are merely my own viewpoint. Hopefully, they will create a possible bridge between one art, music -and a series of sciences. POINTS OF INTEREST AND /OR CONFUSION Relationships between audible non -linear sideband pro- duction and combinational tones (cochlea produced). Construction and possible standardization of waveform identities other than sine, rectangular, sawtooth, stair- case, and triangle. Standardization substitutes for the now confused plug and connector systems (phone, phono, cannon, etc.). Details of acoustical placement of speakers (angle to- ward ceiling, etc.). True "balanced line" properties and priority when con- necting one unit to another. NEVE ANNOUNCES THE NEW 8024 CONSOLE. Where else can Importance of speaker enclosures and possible recon- you get a 24 track recording and do simultaneous quad, stereo and struction of available units for better responses in vari- mono mix downs? able circumstances. This 24 track console provides all the flexibility one can imagine A third possibility of pot control besides vernier and within the astonishing length 80,5 inches. slide, that presents viable clean operation during re- LOOK AT THE FEATURES - 24 In/24 Out Overdub 24 Track cording or playback. Monitoring Full EQ on Every Channel Simultaneous Quad, These represent but a few current problems. A sound Stereo and Mono Mixers Quad Positioning on Each Channel And engineer's glance through Allen Strange's Electronic Music for Added Flexibility There are 240 Jacks. (Wm. C. Brown Co., 1972', Trythall's Principles Gilbert Of course, the Neve quality is built into this console which is and Practices of Electronic Music (Grosset & Dunlap, delivered with its own handbook, spares kit, and all mating XLR con- 1974) and others- including my own New Directions in nectors, and you will be amazed at the low price. Couple this with the Music (Wm. C. Brown 1971) -will give him an insight now famous Neve Service and you again have a winning com- into many other existing problems. Although these books bination. CALL US - might not have solutions to some of the engineer's ques- tions, one must keep in mind that electronic music, taken Rupert Neve Incorporated, Berkshire Industrial Park. Bethel, Connecticut 06801 Tel: (203) 744 -6230. Telex: 969638 since is still a seriously only 1951, baby art. No books Rupert Neve Incorporated, Suite 616. nearing the above quality were available within 25 years 1800 N. Highland Ave., Hollywood, California 90028 Tel: (213) 465 -4922 of the development of the violin! Rupert Neve of Canada, Ltd., 2717 Rena Rood Mallon. Ontario L4T 3K1, Canada Tel: (416) 677 -6611 DEMANDS OF EVER -NEW TECHNOLOGY Rupert Neve & Company Ltd., Cambridge House. Mclbourn, Royston, Hertfordshire., SG8 6A11 England. Tel: (0763) 60776 Possibly the most significant challenge facing the elec- Rupert Neve GmbH. 6100 Darmstadt Bismarckstmsse tronic music composer, as well as the sound engineer, is 114 West Germany. Tel: (06151) 81764 Circle 29 on Reader Service Card

www.americanradiohistory.com ,,,,,,,, II

Figure 1. A sophisticated setup for the interpretation of electronic music.

that of progress. No sooner has one spent his entire budget These two -three man groups would need three vital on what was the best available equipment than another, properties: a common vocabulary for communication, more advanced, synthesizer or module appears. The com- constant role identification in the creative act, and pa- poser can treat that in one of two ways. He can forget it- tience. music is music -and opt out of the expense of valuable Another matter is becoming more and more clear. In- time learning to use the equipment as well as the money stead of the keeping -up- with -the -Jones's attitude of our spent. Or, he can buy the equipment, learn to use it, and colleges (major creators of electronic labs around the usually find that something else yet more advanced is now country), we need to funnel these monies into two or being produced. three large, centrally located laboratories. These labs then A good friend who is currently a director of a com- will become the centers for research in sound engineering puter music studio recently wrote to me: "David, after and for composer creativity. five years I have finally arrived at a complete D/A inter- face for our IBM 7090, only to discover that I have for- INSTITUTE OF SONOLOGY gotten what it was I was going to do with it. To com- Such a center exists at the Institute of Sonology, Utrecht pound the problem, it was recently learned that the com- State University, the Netherlands. This lab is equipped puter time was taken away due to business and science with four complete studios (including computers, synthe- priorities. sizers of all types, and ten professional tape recorders). It Problems and confusions continue. With the advent of employs six scientific staff members, four technical staff light pen writing on CRT inputs for computers, as well as members, and two secretaries. The results are represented the possibility of computers actually reading music for on every major record label in the world and speak for direct analog playback (and voice activation of quick alter- themselves. More than once, an American university has ations), the endless study of voltage controlled synthesizers lost a gifted student to this incredible environment. may have been a wasted one -at least for the composer. My electronic music is listed on two record labels, Dis- cant and Orion, and represents what I hope are crafted COOPERATION A NECESSITY and inspiring compositions. They are, however, far less There is, however, a light at the end of the tunnel when than highly sophisticated in terms of sound engineering, the composer finally realizes that he has worked with and future works will necessarily remain so. It takes years "performers" for years, whether technical or musical, for sound engineers to fully comprehend, in terms of their equally respected for their craft in their own rights. Their own craft, the nuances of interpretation necessary for a relationships may not have been smooth. But it may be- true partnership of the technical and musical possibilities. come apparent that the sound engineer, who takes de- If sound centers became a reality, the opportunity would light in discovering and purchasing new equipment, and be present for the closer sharing of the creative processes. the composer, concerned with artistry, can more than co- When the disciplines of music and technology finally exist. As a flexible unit, they can produce works of music erode their differences, we will come, as Varèse says, . . . N far beyond our current vocabularies. "to the liberation of sound."

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MODERN RECORDING TECHNIQUES STUDIO SOUND-Europe's leading pro- consoles, by Robert E. Runstein. The only book fessional magazine. Back issues avail- DYMA builds custom studio desks, enclosures, studio furniture. covering all aspects of multi -track pop able from June, '73. $1 each. postpaid. music recording from microphones 3P Recording, P.O. 99569, San Fran- Dyma Engineering, Route 1, Box 51, through disc cutting. For engineers. cisco, Ca. 94109. Taos, New Mexico 87571. producers, and musicians, $9.95 pre- paid. To Robert E. Runstein, 44 Dines - AMPEX SPARE PARTS; technical sup- more Ave., No. 610, Framingham, Ma. port; updating kits, for discontinued pro- TASCAM REVERBS -5500; Tascam mix- 01701. fessional audio models; available from ing consoles -$2,350; Tascam 1/2-inch VIF International, Box 1555, Mountain recorders; $1,990; Tascam 8 -track re- corders- $3,490. All shipped prepaid/ WANT TO GO BI -AMP? View, Ca. 94042. (408) 739 -9740. insured, including free alignment /equal- DeCoursey Electronic Dividing Networks ization /bias /calibration. Music & Sound, are available from $89.10 (monaural bi- RENT AN 8 -TRACK SCULLY by the day/ Ltd., 11,2 Old York Rd., Willow Grove, amp) to $205.00 (stereo tri -amp). Price week. Contact F. Rubin, (212) 631 -5919. Pa. 19090. (215) 659 -9251. includes plug Butterworth filters; 6, -in Note Special Prices 12, or 18 dB per octave at any desired cutoff frequency. DeCoursey Engineer- LEBOW LABS, INC., 56 Chestnut Hill ing Laboratory, 11828 W. Jefferson Ave., Boston Mass. 02135. New Eng- Blvd., Culver City, Ca. 90230. land's foremost pro audio /video dis- SPLICE TAPE FASTER, BETTER, BY tributor, representing over 100 major SHEARING. Experts recommend Nagy DESIGN, INSTALLATION and mainte- manufacturers. Sales, consulting, de- splicers. Quality long- lasting instrument. nance for recording studios and sound sign, and service by expert staff. Broad- Reasonably priced. Details, NRPD, Box reinforcement systems. George J. Kereji, casting, industrial, educational, and re- 289, McLean, Va. 22101. 433 Berwyn St., Dearborn Heights, cording installations. Frank Petrella, Michigan 48127. (313) 274 -1476. (617) 337 -6303, (617) 782 -0600. KING MODEL 800S TAPE WINDER (hub); pre- recorded tape winder. will NEW YORK'S LEADING PRO wind either 1/4 in. or 150 mil. widths; as AUDIO /VIDEO DISTRIBUTOR for $2 MILLION USED RECORDING EQUIP- new condition. Also used Rangertone MENT. Send $1.00 for list, refundable, to audio, video, broadcast, public ad- resolver, as is. Gary E. Taylor, Conti- dress, and hi -fi systems; represent- The Equipment Locator, P.O. Box 99569, nental Film Productions Corp., P.O. Box ing over 130 audio /video manufac- San Francisco, Ca. 94109. 6543, Chattanooga, Tenn. 37408. turers, featuring such names as 94109. Ampex, Scully, Tascam, Sony, J. B. Lansing, Neumann, Altec, McIntosh, DYMA builds roll- around consoles for AKG, Dynair, T.V. Microtime, UREI, DIRECT BOX, 50k; 150 ohm transformer; any reel -to -reel tape recorder. Dyma 3M, and other major brands; the 20 kHz _+ 1dB; XLR phone -type con- Engineering, Route 1, Box 51, Taos, largest "in stock" inventory of nectors; ground switch. $42.50. Gately New Mexico 87571. equipment, accessories, and parts; Electronics, 57 W. Hillcrest Ave., Haver- competitive discount prices; factory town, Pa. 19083. (215) 449 -6400. authorized sales, service, parts, sys- DYNACO RACK MOUNTS for all Dynaco tems design. installation. Write for preamps, tuners, integrated amps. $24.95 free catalog! Martin Audio /Video CASSETTE LABELS. blank and custom postpaid in U.S., $22.50 in lots of three. Corporation, 320 W. 46th St., New printed. Free samples. Tarzac, 638 Mus- Audio by Zimet, 1038 Northern Blvd., York, N.Y. 10036. (212) 541 -5900. kogee Ave., Norfolk, Va. 23509. Roslyn, N.Y. 11576. (516) 621 -0138. w w (continual)

www.americanradiohistory.com FOR SALE FREE CATALOG & AUDIO APPLICATIONS CONSOLES KITS 8 WIRED AUDIO DESIGNS CONSOLE. Compo- AMPLIFIERS nents: Ten 700. six 770 modules and M IC. EO, AC N, AUDIO PRO CLEANER LINE, TAPE, DISC, supply. Best offer. SSi. (716) 695 -3500. POWER The new cleaner that OSCILLATORS sensational eats AUDIO up studio grime, makes your equip- OPAMP LABS. INC. TAPE BIAS POWER SUPPLIES AKG, ADVICE, Audio Research, Beyer, ment look like new, cleans heads, Crown, dbx, Infinity, Integrity, Koss, tape guides. capstans ... and every- Maxell, Nakamichi, Phase Linear, PML, thing else in the studio. Send $11.95 BODE FREQUENCY SHIFTERS since Revox. SAE, Scotch, Sennheiser, Ser- for one gallon plus 8 oz. sprayer post 1963 . . . Advanced designs for elec- vice, Shure, Sony, Stanton, Stax, TDK, paid to: tronic music studios and high quality Tascam, Technics, Thorens. etc. Hi -Fi AUDIOTECHNIQUES, INC. P.A. systems. New real time perform- Haven, Inc. 28 Easton Ave., New Bruns- 142 Hamilton Ave. ance, synthesizer compatible model wick, N.J. 08901. (201) 249-5130. Stamford, Conn. 06902 (patented features): $995.00. Anti -feed- (203) 359 -2312 back and special effects model with variable frequency shifts, down to 0.5 FOR SALE: AUDITRONICS CONSOLE; Hz.: $575.00. Prices f.o.b. North Tona- 24 -in /24 -out; full quad; quad reverb PROFESSIONAL CASSETTE DUPLICA- wanda. Delivery: stock to 6 weeks. For with two API joy sticks; built -in stereo TION, any length. stereo or mono., any details and information on other models. radio speakers; two producers' desks; master acceptable.. Dolby. Cantor Pro- write to: Bode Sound Co., Harald Bode, used nine months; will include 16 ITI ductions, 26 W. Nottingham Rd., Day- 1344 Abington Place, N. Tonawanda, parametric equalizers (brand new). Total ton, Ohio 45405. (513) 6571. N.Y. 14120. (716) 692 -1670. original cost of this package: $37,720 - your price: $27,000! (If you want only 18 inputs, the total cost will be $24,000.) FOR 8 -TRACK se- WHATEVER YOUR EQUIPMENT NEEDS SALE: 3M recorder, Will separate and will finance. Contact ries 400. excellent specs, excellent con- -new or used -check us first. We spe- Paul. (312) 225 -2110, Chicago. dition. Going 16- track. $7.000. NWI Stu- cialize in broadcast equipment. Send $1.00 for our complete listings. Broad- dios, 011 S.W. Hooker, Portland, Ore- gon 97201. (503) 224 -3456. cast Equipment & Supply Co., Box 3141, NEUMANN DEALER has demonstrator Bristol, Tenn. 37620. to sell with full warranty: model U -87 with accessories. $500.00. The Audio Marketplace, Div. U.A.R., 5310 Jack - MCI . . . DOLBY. Two great names! NEW & USED 1/2-in. recording tape on Two great products! For authorized fac- wood, San Antonio, Texas. (512) 684- metal reels. New Ampex 11/2 mil 2500' tory representation in the progressive 4000. $7.75 each; 1 mil, $8.25 each; used Midwest. contact: Jerry Milam, Milam Scotch, 206, $7.00 each; new and re- Audio Co., 700 W. Main St., So. Pekin, conditioned metal reels, (all sizes). SCULLY, ELECTRO- VOICE. NEUMANN, III. 61564. (309) 348 -3112, 9605. Soundd Investment, P.O.B. 88338, At- Shure, Spectrasonics, Quad Eight, Mas- lanta, Ga. 30338. terroom, ARP, Pultec, Mictrotrak, Russco, dbx, Interface, EMT, and others. The CUSTOM CROSSOVER NETWORKS to Audio Marketplace, Div. United Audio DISCOTHEQUE MIXERS from $325.00; your specifications; a few or production Recording, 5310 Jackwood, San An- equalizer speakers with built -in power quantities. Power capacities to thou- tonio, Texas 78238. (512) 684 -4000. amplifiers; bi -amped systems and com- sands of watts; inductors and capacitors plete portable discotheque systems. available separately; specify your needs Write us for literature. Dealer inquiries for rapid quotation. Also, PIEZO ELEC- ORTOFON invited. GLI, Box 2076, Dept. D, Brook- TRIC TWEETERS -send for data sheet DYNAMIC MOTIONAL FEEDBACK mono lyn, N.Y. 11202. (212) 875 -6992. and price schedules. TSR ENGINEERING, disc cutting systems. Complete with 5146 W. Imperial, Los Angeles, Ca. drive, feedback. and feedback -playback 90045. (213) 776 -6057. monitor amplifiers and cutterhead. All systems guaranteed. Spare cutterheads AVAILABLE SERVICES. Milam Audio Co. available for exchange /repair. Albert B. specializes in every phase of profes- Grundy, 64 University Place, New York, sional studio wiring, from complete sys- DISKO MIX -MASTER I for disco use N.Y. 10003. (212) 929 -8364. tems to individual pre -wired parts and and /or preparation of disco tapes. Mixes components. Available from stock: patch two stereo phono inputs with self -con- bays, custom mic panels, multi -paired tained headphone cueing amplifier. Send B.B.C. REFERENCE MONITORS, cabling and harnesses. etc. Milam for literature. $129.00. Dealer inquiries PRE -EQUALIZED J.B.L. /Altec moni- Audio Co., 700 W. Main St., So. Pekin, invited. Berkshire Audio Products, P.O. tors; Dahlquist phased arrays; I.M.F. III. 61564. (309) 348 -3112, 9605. Box 35, Great Neck, N.Y. 11021. transmission lines; Infinity electro- statics; Crown/McIntosh 16tí /bridged bi -amps; Scully /Revox A -700 record- A FEW competitively priced used Revox ers; Micmix /Parasound /Multi -Track A77 decks available. Completely recon- reverbs; Eventide flangers /omnipres- ditioned by Revox, virtually indistin- sors; Lexicon digital delays; dbx/ * SERIES "B" MIXING CONSOLE guishable from new and have the stan- Burwen N.R. companders; Little Dip- Revox warranty for * VARI -BAND 5 SECTION dard 90 -day rebuilt per hum /buzz notch filters; Cooper machines. Satisfaction guaranteed. Ex- PARAMETERIC EQUALIZER Time Cube echo send; moving coil ample, A77 with Dolby, $675, plus ship- Denon /Ortofon; B&O/ Rabco straight * DUAL EQUALIZED REVERB ping. Write requirements to ESSI, Box line arms /cartridges; Studer /AKG/ * LONG & SHORT THROW SLIDE 854, Hicksville, N.Y. 11802. (516) 921- Sennheiser condensers; Beyer rib- 2620. FADERS bons, U.R.E.I. comp /limiters /cross- overs; Gately pro -kits; Q.R.K. turn- * HIGH BALLISTIC VU METER tables; White equalizers; 1000s more. THE LIBRARY . . . Sound effects re- Music & Sound, Ltd., 111/2 Old York corded in STEREO using Dolby' P.O. BOX 3187 Rd., Willow Grove, Pa. 19090. (215) throughout. Over 350 effects on ten 659 -9251. HOLLYWOOD, CA 90028 discs, $150.00. Write, The Library, P.O. All Shipped Prepaid - Insured - (213) 467 -7890 Box 18145, Denver, Colorado 80218.

www.americanradiohistory.com MCI ... Now the best selling multi- ONE STOP AUTOMATED QUAD PANNING track recorder! FOR ALL YOUR PROFESSIONAL THE UNIQUE AQC SYSTEM (PAT. APPLIED FOR) CAN DO WHAT HANDS CANNOT MCI ... only from Audiotechniques, AUDIO REQUIREMENTS 4, 8, 16 & 24 INPUTS Inc. in the great Northeast! BOTTOM LINE ORIENTED VIDEO & A LIDIO ARTISTRY CORP. F. T. C. BREWER CO. Tape recorders from one track to 24- p.o. box 4571, boulder, colorado 80302 track. P.O. Box 8057, Pensacola, Fla. 32505 (303) 499 -2001

Recording consoles up to 40 input NEW MODELS: Ampex AG440C 2- track. WANTED MCI sales -service servo capstan motor; Scully 280B; used factory trained technicians AG440Bs; used Scully 280, 8- track, new WANTED: B & O Stereo microphone, Studio design and heads, in console, excellent condition; model BM -5. Box 81, db Magazine, construction service Sennheiser mics. Immediate delivery 1120 Old Country Rd., Plainview, N.Y. from stock. Malaco Recording, Jackson, 11803. AUDIOTECHNIQUES, INC. Miss. (601) 982 -4522. 142 Hamilton Avenue Stamford, Conn. 06902 WANTED: Educational public broadcast PERFORM REAL TIME AUDIO ANALY- (203) 359 -2312 station needs surplus studio equipment, SIS with your oscilloscope! Just add particularly magnetic tape and mixing new ARA -412 Acoustic Response the equipment. Contact Boulder Community Analyzer -$1.295.00. Write for free data Broadcast Association, 885 Arapahoe, MOTORS. Factory re- Inc., AMPEX CAPSTAN sheet: Communications Company, Boulder, Colorado 80302. placement for model 300 or 3200 dupli- 3490 Noell St., San Diego, Ca. 92110. cators, 1800/3600 rpm, $140.00 xchange. Tellet Communications, 8831 Sunset EMPLOYMENT Blvd. W., Hollywood, Ca. 90069. (213) MONITOR EQUALIZERS for your Altecs 652 -8100. & J.B.L.s are a steal at $75 /channel SALES MANAGER. We are looking FREE ROOM EQUALIZATION with pur- USED: GATELY SPM -6 (plus) $650; B &K for an aggressive sales manager to chase of 1/3 octave filters. This is not 1470 oscilloscope (plus) $400; Sound - sell our complete line of console a misprint. Music & Sound, Ltd., 111/2 craftsman 2012. $200; Advent 100A. components for recording. broadcast. Old York Rd., Willow Grove, Pa. 19090. SM -54 (plus) $110. and sound reinforcement. Individual case, $180; Shure (215) 659 -9251. SM -50. $50; (2) Sony ECM -22p. $70; (3) must be an experienced pro with a S.M.E. Damping Mods -$30.00 direct boxes. $20. (218) 728 -2695. proven performance record. National distribution. Modular Audio Products, 1385 Lakeland Ave., Bohemia, N.Y. HARMONIC PERCUSSION for any Ham- AMPEX, SCULLY, TASCAM, all major 11716. (516) 567 -9620. professional audio lines. Top dollar mond organ. Easy to install. Linear De- trade-ins. 15 minutes George Washing- vices, Dept. 3, Box 5750, San Fran- ton Bridge. PROFESSIONAL AUDIO cisco, Ca. 94101. VIDEO CORPORATION, 342 Main St., Paterson, N.J. 07505. (201) 523 -3333. AMPEX SERVICE COMPANY: Complete factory service for Ampex equipment; professional audio; one -inch helical scan LOWEST PRICES IN THE COUNTRY on video; video closed circuit cameras; microphones, power amps, speakers, video systems; instrumentation and con- musical instruments, P.A. equipment, sumer audio. Service available at 2609 including Peavey, Heil, J.B.L.; huge Greenleaf Avenue, Elk Grove Village, stock, top brands only. Gracin's 110, III. 60007; 500 Rodier Dr., Glendale, 606 Rte. 110, Huntington, N.Y. 11746. Ca. 91201; 75 Commerce Way, Hack- WORAM AUDIO ASSOCIATES (516) 549 -5155. ensack, N.J. 07601. Consultants in Studio Systems Engineering, Design and Installation RECORD /PLAY ELECTRONICS. new SOUND 80 IS REPLACING all 1/4" ma- Langevin mono solid- state, $250 each; chines with new MCIs. We have Scully also matching heads. GE torque motors. 280s: Three mono full- tracks; one 4/2 -offering- $40. Special price for lot. Discontinuing playback; one transfer master with pre- this product. Contact Dave or Wally, view head and electronics. Two Ampex Tapeathon, Box 814, Inglewood, Ca. 300 transports with Inovonics electronics A COMPLETE CONSULATION 90301 (213) 776 -6933. and new heads. All machines are con- SERVICE FOR STUDIO sole- mounted and in mint condition. Two Pandora time lines, like new; one PLANNING AND ONE WAY NOISE REDUCTION for cut- Roger Mayer RM -58 limiter; two dbx CONSTRUCTION ting rooms/tape copies; retains highs, noise reduction cards; one Dolby M -16; rids hiss /surface noise & clicks /pops two Countryman 968 phase shifters. FREE -LANCE RECORDING by a full 10 -14 dB and costs $170 up Sound 80, Inc., 2709 25th St., Minne- per channel! Music & Sound, Ltd., 1112 apolis, Mn. 55406. (612) 721 -6341. SERVICE IN THE Old York Rd., Willow Grove, Pa. 19090. NEW YORK AREA (215) 659 -9251. ACTIVE BUTTERWORTH FILTERS for electronic crossovers: 4 poles, highpass or lowpass, 24 dB per octave rolloff, 212 673 -9110 REPAIR 11/2 x 2 inches, $14.95; 8 poles. lowpass, SCHOEPS iTELEFUNKEN) VACUUM TUBE 64 University Place 48 dB per octave rolloff, 2 x 3 inches, CONDENSER MICROPHONES REPAIRED. New York, N.Y. 10003 Original factory parts & factory calibration of capsules. $19.95. Specify cutoff frequency 500 Hz Models CM51, 61, 661 M201. 221, MK24, 26 etc. to 20,000 Hz. FREE catalog. (601) 323- ALBERT B. GRUNDY 5869. MFJ Enterprises, Box 494, Missis- 64 University Pl., N.Y., N.Y. 10003 sippi State, Ms. 39762. (212) 929 -8364 Isla >a

www.americanradiohistory.com o peoe/pbces/happenings

Of interest to those in or servicing the music industry, International Mus- Pioneer General Electric expo '75 will take place on September Company engineer. Dr. Ernst 21 -24 at the Las Vegas Convention F. W. Alexanderson, died on Center. The exhibition will feature May 14 at the age of 97. Dr. firms from the United States and Alexanderson. an associate of Europe. including the communist Steinmetz and Marconi, received countries. Russia will be represented a total of 322 patents during by Mezhkniga, the official agency that his 46 -year career with GE. His imports and exports recordings, sheet most significant contribution was music, and books. The exhibit will a high- frequency alternator, one display wares from recording com- of the seed inventions that led panies, studios, and audio accessory to the development of modern manufacturers. Roddy S. Shashoua is radio. Previous to the invention focalizing the exhibit. The address of LEON A. WORTMAN of the alternator, only dots and MUSEXPO is 135() Avenue of the dashes could be transmitted by Americas, N.Y.C. 10019. Telephone wireless. Wireless operators on number is (212) 489 -9245. ships on historic Christmas Eve, effects libraries, spectator seating, of- 1906 were astounded to hear fice facilities, and shipping service. Thee Studio, of Claremont. Ca. voices coming over the wires. Musical instruments are available free now boass a new 16 -track recording - They were hearing Dr. Alexan- of charge. George Agoglia is director mixdown facility, built by Everything in action, of operations. derson's alternator and Audio. The studio is equipped with the birth of radio. In addition the Spectra -Sonics 1024 console, 24- to the alternator, Dr. Alexan- in,'24 -out, an MCI 16 -track machine. L.A.W. Associates, providing spe- derson developed the magnetic and Dolby noise reduction. The moni- amplifier, the electronic ampli- tors are JBL 4341s powered by cialized marketing and sales consultant services to audio and closed circuit fier, the multiple tuned antenna, Crown amplifiers. The studio is lo- the anti -static receiving -antenna, cated at 224 N. Indian Hill Blvd. television firms, has been formed by Leon A. Wortman. The new firm's and the directional transmitting antenna. He John Pritchett has been appointed office is located at 743 Holly Oak also devised radio to the post of president of Quantum Drive, Palo Alto, California. Mr. altimeters, and his studies in the Audio Labs, Inc. of Glendale. Ca. Wortman, who was formerly with the polarization of radio waves made Mr. Pritchett. a public address tech- Ampex Corporation, is the author of possible effective radio di- nician, recording engineer, and de- the CCTV Handbook. rection finders. He was instru- signer, comes to Quantum from the mental in the development of James E. Lansing Company. He has shortwave uses and television. also been associated with Altec. University of Wisconsin, Madison. Wisc., will host a three -day Sound Recording. mixing. and editing Engineering seminar September 3 -5. from 16 tracks down to mono will be The seminar. conducted by Don Davis, offered by Studio 21, new recording will cover the following: Design of a ply is less because the supply dissi- facility located at 635 Madison Ave- biamped system; use of digital time pates less heat and thus requires less nue, New York City. The studio has delay; where to place loudspeakers; cooling." Dr. Salzer also pointed out high speed duplication facilities, sound filter sets; altering loudspeaker cover- that at higher ratings. switching power age patterns; acoustic levels and elec- supplies will still dissipate an accept- design able level of heat, in contrast to linear SPECIAL: dB BINDERS trical power; and placement. To enroll, contact: Lowell B. Jack- regulators. which are seldom used at This handsome vinyl binder will son, Dept. of Engineering. University the 300 -watt level or above. Other ad- hold an entire year's issues of db The of Wisconsin-Extension. 432 N. Lake vantages are compactness and sim- Sound Engineering Magazine. It makes St., Madison, Wisc. 53706. plicity of support and mounting. Al- an easy -to- handle reference guide and though there has been resistance to only requires a minimum of space in power switching because of the ex- your office or on your bookshelf. A A radical saving of power, to the pense and natural suspicion of new limited supply is available at $5.95 tune of 400 million watts, through the techniques, the study indicated con- each on a first -request basis. use of switching power supplies in tinued growth in this area, projecting place of linear regulators, is possible, from two percent in 1973 to thirty according to findings published by percent by 1978. db Magazine, 1 120 Old Country Rd. Darling & Alsobrook as part of a four Plainview, N.Y. 11803 volume International Electronic Pack- Jack Valenti, president of the Mo- aging series. According to Dr. John tion Picture Association of America Here's my $5.95. Send me a binder. Salzer, vice president of the Los An- and Special Assistant to the President geles management consulting firm. Name of the United States during the period "The cost of a switching power supply 1963 -66, will be the guest speaker Address can be ten to as much as fifty percent at the get- together luncheon of the higher than that of a linear regulator SMPTE conference scheduled for Sep- of the system co type, but the overall cost tember 28- October 3, at the Century co J incorporating a switching power sup- Plaza Hotel in Los Angeles.

www.americanradiohistory.com JBL's new 4315. There's never been a wider range studio monitor Of any size.

And, four more things: It's a four way system. It has the most sophisticated cross- over network ever designed. It's compact, shallow, portable. Perfect for wall mounting, horizontally or vertically. It's yours for $714. There's more. Much more. Go hear the rest.

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James B. Lansing Sound. Inc. Professional Division 3249 Casitas Avenue Los Angeles 90039 DOL www.americanradiohistory.com THE PEIVEY 1200 MIXER

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In response to the market demand, we present the 1200 Mixer, the first truly professional mixer for less than $1,000.

12 transformer balanced, low impedance mike inputs 12 unbalanced, high impedance line inputs Input attenuation & mike /line selection High and low equalization on each channel Stereo pan on each channel Three send controls on each channel, all having pre or post capability Output slide attenuators on each channel Master control area consisting of left & right main slide attenuators with associated low, middle & high equalization and monitor slide attenuator.

4 Effects master, return & pan controls Reverb master, return, & pan controls pir 600 Ohm transformer balanced outputs on left & right main and monitor Lighted VU meter on left & right mains, externally adjustable. Suggested Retail Price $949.50 f Err

MORE ABOUT THE 1200 MIXER WRITE: PEAVEY ELECTRONICS, BOX 2898, MERIDIAN, MS. 39301

Circle 23 on Reader Service Card www.americanradiohistory.com