.

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Research and development went hand in hand. First, a suitable magnetic oxide had to be produced. Then, a tough, nontearing, moisture resistant base on which to coat the oxide. Finally, we had to design and build a high quality recorder and reproducer in order to test the results of our experiments.

Exhaustive experimentation on magnetic iron oxide included tests on many hundred samples from our own laboratories as well as from others, tests which included signal to noise checks, distortion measurements and relative frequency response, finally convinced us we had surpassed the Germans in the oxide part of our work.
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• Anmerkung : Natürlich haben die "AUDIO DEVICE"-Leute die "Germans" übertroffen, was denn sonst, aber haben sie auch 3M und ORR übertroffen.
  
  ORR Radio arbeitete seit Mitte 1945 an einer neuen Magnetbandproduktion und 3M hatte einen noch viel größeren Vorsprung durch den Kontakt mit der Firma Brush Development und Samuel Begun. Der ORR Radio Chef Colonel Ranger hatte sogar getönt, er hätte das erste amerikanische Magnetband bereits nach 2 Wochen fertig gehabt, er hätte nämlich (angeblich) von einem Deutschen von der IG Farben diese "formula" (also die Mixtur) bekommen.
  
  Das ist (war) natürlich alles ziemlicher Unsinn, denn alleine solch eine Kugeltrommel, das ist der speziell beheizte Mischer mit den vielen tausenden von Präzisions-Kugeln drinnen, zu entwickeln und produktionsreif zu machen, ist eine mechanische Herausforderung und eine Meisterleistung.
  
  Auch einen "Kalander" schüttelt der beste amerikanische Werkzeugmacher nicht mal so aus dem Ärmel. Ein Kalander ist eine unglaublich aufwendige Hochpräzisionswalze mit 2 gegenüberliegenden Trommelwalzen für allerdünnste Folien im "müh"-Bereich, aber mindestens 50cm breit !!!!!.

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At present, we are using a vinyl "film" as the base or support for the oxide dispersion. We chose this material because of its free flowing character; a limp highly flexible tape is essential for proper contact with the magnetic heads. Vinyl is also dimensionally stable in spite of changes in humidity, a state unachieved by paper or acetate. Stretch or shrinkage of as little as 1/2 of 1% would be ruinous in a half hour of broadcasting. Finally, we chose a film, which is highly tear resistant, a property of great importance both for amateur or professional.

However any base is at best a compromise and we feel sure that in due course of time a still better film can he developed which will have all the properties of the best German tape without the disadvantage which apparently they were unable to overcome, i.e., loss of dimensional stability when subject to heat.

Audiotape (trade marked) was chosen as the name for our product and is in our opinion a very proud and suitable companion for Audiodisc. (See cut.)

Audiotape virtually has no surface noise. Under ideal conditions, the signal to noise ratio is something more than 60 db. Equally important is the phenomenally low noise behind signal, probably equal to or superior to the best German efforts.

Frequency response depends on the particular machine used and of course the linear speed of the tape. This is simply to say the "tape" itself has no frequency response. The measurements are relative only, depending upon various factors.

Audiotape, when run at 7 1/2" per second, is substantially flat to 7000 cy. When run at 18" per second, that is at the speed of motion picture film, it is flat to above 9000 cy., and when run at Magnetophone speed of 150 ft. per minute, is flat to above 15,000 cy. which is required for FM-Broadcasting. These measurements are all about 2.000 cycles better than other tape now available.

Distortion measurements are still more difficult to make because every type of tape has a critical bias. Intermodulation tests indicate extraordinary satisfactory results, however more work is still to be done before final figures can be obtained. Nonetheless measurements for harmonic distortion indicate a figure not above 1/2 of 1%. Audiotape is being made available in limited quantities for test purposes. However, within a few weeks we expect to be in full production and as in the case of Audiodiscs, distribution will be carried on by our present distributors.

Audiotape is wound in 1275 ft. lengths on lightweight 8" diameter aluminum reels, made especially for Audio Devices, and on 4700 ft. aluminum flanges, 13 1/4" diameter, adaptable to either Magnetophone or the several variations now coming on the market.
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Audiotape will do many things impossible to realize with discs. For editing, assembling, etc., tape has no peer, on the other hand, one must bear in mind the skill, training and ability of the operator is of first importance if the complete benefits of tape work are to be enjoyed. In our opinion, Audiodiscs and Audiotape are natural complements, each will augment and assist the other in bringing fine recording to the home and studio.
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• Anmerkung : Natürlich wissen wir heute, daß noch mehrere Firmen in USA versucht hatten, dieses "Magnetophone"- Band herzustellen und daran gescheitert waren.
  
  Denn die alten BASF-Spezialisten hätten sich lieber "etwas (es hängt zwischen den Beinen) abgeschnitten", als den Amerikanern die genauen Details zu verraten. Selbst die Deutschen, die sich über das Ende des Krieges - in der amerikanischen Zone - gefreut haben, hatten die amerikanischen Bomberpulks über Mannheim und Ludwigshafen (BASF) und Heidelberg und Darmstadt nicht vergessen.
  
  Und dann waren es ja die kleinen Feinheiten, die die I.G.Farben / BASF-Ingenieure und Chemiker in den Jahren zuvor akribisch ausgetüftelt hatten. Es gibt nämlich ausführliche "FIAT-Protokolle" von Forschungen auf diesem Gebiet - aber alle erst aus 1949, als die amerikanischen Ingenieure und Chemiker dem "Geheimnis" der Magnetbandproduktion so langsam auf die Spur kamen.

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Students who hope to make the grade (Ausbildung / Examen) as announcers (Ansager), actors (Schauspieler) or producers (Produzenten / Redakteure) on Fordham University's FM broadcasting station, WFUV, must come up to professional standards; and the best method of perfecting their talent is a maximum use of recording facilities, according to William A. Coleman, Chairman of the Radio Division, Dept. of Communication Arts.

Common practice in classes such as Voice and Diction at the New York school is to record each student at the beginning of the course and again at the end of the course, at which time the correction of defects and general improvement should be obvious.

Tom O'Brien, NBC staff announcer who teaches Microphone Technique on the Bronx campus, makes continuous use of tape-recording equipment to permit students to hear themselves as they read commercials, attempt tie-in announcements, and render dramatic narrations. When a student is considered of professional calibre and wishes to apply to a commercial station for work after graduation, he is assisted in cutting an audition disc for submission to his prospective employer. Similarly in the course in Acting for Radio, taught by Clayton "Bud" Collyer ("Superman" of the air waves), a particularly good actor or actress will be encouraged to put on a record the characters in which he or she excels.

Ernest Ricca, well-known freelance Director ("Helen Trent", "Evelyn Winters", etc.), whom Mr. Coleman has teaching the course in Radio Direction and Production at Fordham, is emphatic about the necessity of students hearing their directorial attempts played back. "Until they are proficient enough for air work", he says, "students must work hard at improving. This means a constant process of directing, listening, and learning."

High fidelity RCA recording equipment in the studios of WFUV is augmented by several portable tape recorders and "Educator" type record cutters, the latter restricted principally to classroom use.

Many Fordham programs which would otherwise be impossible are arranged by having them recorded at a time convenient to the persons scheduled to broadcast. Thus, Faculty members who might have a conflict between the program, "The Faculty Speaks" and a regular class are permitted to be heard by both audiences simultaneously.

In the case of Godfrey Schmidt, "The Story Teller", a busy industrial lawyer is able to double as a broadcaster of delightful fairytales, by the simple expedient of having him record five stories for the week during a single Saturday cutting session. The success of this program was such that WNBC-New York now airs the Attorney-turned - Story Teller each Thursday evening.

Finally, by means of recordings, Fordham University's WFUV is taking steps to better international understanding. Under the Rev. Richard F. Grady, S. J., Manager of the station, a series featuring American folk songs with appropriate language commentary is being recorded for distribution to Radio Eire, the French State Radio, and the broadcasting networks of other countries.

"Radio may be only a year old at Fordham," Mr. Coleman says, "but both in classroom and on the air, New York's first Educational FM station is doing a bang-up job ... on the record."

By Aaron S. Bloom - Treasurer, Director, Commercial Dept. - KASPER-GORDON, Inc. - Boston, Mass.
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• Anmerkung : Eigentlich ist es eine Anleitung für Werbetreibende und Werbeagenturen in den USA, wie man am besten irgendwelche (Rundfunk-) Produktionen (sie nennen es "Shows"), die man sowieso "gemacht" hatte, auch in Nischen-Märkten, also den kleinsten und nicht landesweit vernetzten Radiostationen auf dem weiten Land, gewinnbringend vermarktet.

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The old adage that "you can't teach an old dog new tricks" has been blasted as thoroughly and as effectively as were two Japanese cities by the A-bomb. Many longtime advertisers have discovered the practicability of the transcribed radio program, both custom-built transcription series built specifically for their own use, as well as the open-end syndicated transcribed program series.

The "discovery" was made the hard way, insofar as transcription producers are concerned, for transcription companies found it difficult to educate advertisers on the many advantages the transcription program had and has over the network and regional program - advantages with which no network or regional show could possibly compete. But the radio advertiser knows now, and legion indeed are the number who now use the e. t. program.

For example: can't clear time on a network? So what? Put the show on discs and select the best available time in the markets you wish to cover.

• Anmerkung : Wenn alle aktuellen (lukrativen) Sendezeiten in den großen (Radio-Stations-) Netzen belegt sind, wird sinnvollerweise die Show (in Amerika war fast alles nur "Show") aufgezeichnet und zum Vermarkten der bestmöglichen (für kommerzielle Werbung günstigsten) Sendezeiten bereitgestellt.

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You can't buy a split network?
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• Anmerkung : Man konnte die Netzwerke der großen Senderketten nicht splitten, entweder buchte man alles an Programmen - also von sämtlichen dort angeschlossenen Sendestationen - oder eben nichts.

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You must buy time in some cities you don't want, or where you have no distribution as yet? Don't let that bother you. Just put the show on discs and select the markets you wish. Then again, must you be saddled with a particular station your dealers just don't feel partial to, but which you must use because it is part of the network? Don't pull your hair out by the roots. Disc the show and buy time on the stations you want.

But then - suppose you don't want to build an expensive custom-tailored show to test a product in a certain market, or group of markets. In that case, there are many good openend transcribed syndicated shows to use - programs which cost a lot of money to produce, but which the individual sponsor in any market may purchase (lease) to make the test - shows which range from gospel songs to musical variety, from sports programs to mystery drama, from adventure to juvenile fairy stories.

• Anmerkung : Hier wurden die sogenannten "Shows" mal aufgelistet, alles war dabei, von religiösen Veranstaltungen über Musicals und Varietés bis zu mehr oder weniger interessanten Hörspielen.

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There are shows with well-known names which cost the advertiser only a fraction of the expense of a custom-built program - even shows without the so-called "big names", but which have a proven record of success in the building and holding attention of listeners, and in selling merchandise. Actually, many such shows without those "big names" have pulled greater results per dollar of expenditure for time and program, than have some of the more costly "big time" shows with the so-called "stars". The payoff isn't always in the "big name", or even in the ratings. It's in the jingle of the sponsor's cash register. And currently, sponsors are looking more critically at those "ratings". They are finding that the "cost per point" for expensive shows is two, three or even four times as much as for more moderate productions.
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Yes - the transcribed show is here to stay - and nothing more need be said to justify the recorded program than to point to the hundreds of sponsors of national importance, and the thousands of regional and local advertisers, who now use transcriptions on radio stations throughout the U. S., Canada, and all foreign countries where commercial programs are accepted.

In many instances, the syndicated transcribed show is an even better "bet" for sponsors to use, than some locally produced "live" talent programs, especially insofar as smaller markets and stations are concerned. Aside from the fact that the syndicated transcribed show costs less, there is usually less worry about the talent available in local markets, production of the show, and certainly no concern about script, rehearsals and timing of the transcribed program. It's all completed! The sponsor knows in advance how the 15th or 50th program in a series will sound, because it's all there on disc for him to hear.

Too, reputable syndicated program producers are as careful of the production that goes into their various packages (as a rule) as are network producers. They have to be. It's their money they are gambling. And they depend upon the success of a series for a sponsor, so that they can sign the same client up for a continuation of the series, its use in other markets, or for another show - whether syndicated or custom-built.

The use of the word "reputable" is not meant to include the "producer" who records two programs as samples, sets out on a selling expedition in the hope of signing enough business to warrant investment in a series of 26, 52, 78 or even 130 or 260 programs in the series. The reputable producer finishes his series before offering it, or has earmarked enough money to complete the number of shows offered, whether one sponsor or 100 signs. The "2-sample producer" who doesn't sign enough individual markets to finance production of the entire series, and therefore never completes all the programs and therefore never delivers them, generally exits quickly from the syndicated field. But while he is in it, he does it little good. As the oldest syndicated transcribed program producer in the United States (more than 16 years) we have seen them come and go with monotonous regularity.

There's a lot more to this business of syndicated transcriptions than merely producing a series of transcriptions and offering them for sale. The producer must be prepared to make a huge investment, and then take his chances on getting it back. He must know every market in the United States (as well as foreign countries where his programs are adaptable) and how much to expect per program for each market, considering the population, power and rates of radio stations, and cost of production of the program series.

The producer must assist the sponsor in working out promotional campaigns, be ready to supply publicity material, small space ad mats, teaser spots, merchandising and exploitation suggestions. And lots of other things of which there is no space to mention herein.

Be that as it may, the advantages of the transcribed programs - both custom-built and open-end syndicated shows - are making themselves felt more and more. The results as far as the producers and pioneers are concerned may not be as sensational and as sudden as was the atomic bomb. By that I mean that the producer doesn't see his sales and business skyrocket, with wealth rolling in for his efforts overnight. But who wants to break down sales resistance and destroy the customer at the same time? The transcription business has been built step by step - and it's always better to have a solid foundation for anything.
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Alan H. Bodge, for a year and a half a member of Audio Devices' New York Sales Department, has been appointed manager of the company's new west coast office at 844 Seward Street, Hollywood, Calif. Prior to joining Audio in the spring of 1946, Bodge, a Dartmouth graduate, spent fifty-three months in the radar division of the Army Signal Corp.
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• Anmerkung : Hier oben drüber nur ein Beispiel dieser typischen - für fast alle Leser nutzlosen - Pressemeldungen, der Mitarbeiter "yxz" gehe in eine neue Filiale - oder so ähnlich. Das gab es in unseren diversen Hifi-Magazinen viel zu oft und in der Funktechnik und Funkschau war es zunehmend lästig. In der FKTG Zeitung für Film- und Fernsehangehörige ist es heute noch ganz ganz wichtig (also ebenfalls unwichtig).

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A number of steps will be necessary before we have a full fledged profession:

• A. We will have to develop the habit of free discussion of common problems.
• B. We will have to develop an organization for cooperative attack on common problems.
• C. We will all have to realize that there is no single magic "secret" which makes recordings marvelously superior. Good recording is the result of the summation of many factors, of taking infinite pains. The magic secret perhaps existed back in the old acoustic recording days, when the art was much more simple, but it is certainly non-existent today.
• D. To execute these steps we will have to develop a tradition of general publication. The doctors have made such extensive progress in a much more complex subject only because every new idea is quickly published and studied. The individual contributes only his own single idea, but he gets back in return everyone else's ideas - a yield of a thousand for one. In the past, general audio publication was badly hindered by lack of a suitable medium. We have had a suitable journal available for several months, and other audio engineers are beginning to write more freely. Disc recordists need to follow the example so set.
• E. Still missing is a suitable professional organization to sponsor regular audio engineering meetings, but steps are under way to remedy this.
• F. It will also help greatly if publication carries more prestige. Progress in the radio-frequency field has been greatly helped by the fact that publication carries with it improved professional standing. In the more progressive organizations in the audio field this is also true, but in too many places publication is regarded as a laborious chore rather than as an opportunity to make friends in print. It is very pleasant to arrive in a strange city and find that you are not a stranger - for your writings have already made you known.

Editor's Note: Mr. LeBel will be pleased to have recording engineers' comments on the above ideas. What do you think ?

Listeners Given Quicker Eye-Witness Coverage of Special News Happenings

Equipped with a transcription library valued at half a million dollars and a crack staff of on-the-spot reporters, WOR-New York has perfected the use of transcriptions in news broadcasts to what probably is its most mature development. This development, increased since the war, results in more authentic broadcasts and gives listeners quicker eye-witness coverage of news events.

When a news story breaks, such as the search for the missing recluse, Langley Colyer, WOR reporters are sent to the scene wherever practicable to record descriptions of the event which are in turn inserted into regular news broadcasts. Reporter John Wingate, for example, was on hand when Collyer's body was discovered, described the event and raced his recordings back to the station so that WOR listeners might hear a complete story before the newspapers had hit the streets. During recent investigations of the House Committee on unAmerican Affairs WOR newscasts were supplemented with recordings of actual testimony given during the hearings.

The wedding of Princess Elizabeth furnishes another example of the way recordings are used to give listeners better programs. Highlights of the event, which took place too early in the morning for most American audiences, were transcribed, edited and re-broadcast at times more suitable for listeners. Such news coverage has the authenticity of newsreels plus the added advantage of speedy presentation.

Transcriptions also provide a backlog of events and personalities of the past, and the WOR transcription library has on file voices and opinions of almost every national and international leader of the past two decades. When major issues of the past, such as elections or international conferences recur, WOR can summon at a moment's notice, presidents, dictators, generals and a host of others to give their views on the same or similar problems.

Casual interviews with the unpublicized average citizen, as well as with the great and the famed, form a valuable index to public opinion. The reaction of the ordinary voter to national problems is naturally a consistent augury on political trends. - Few places are inaccessible to the radio reporter since the advent of the recorder and WOR has endeavored to make everyday folk the source as well as the consumer of news.

The use of the transcription in news broadcasting gives the Listener better news service in spot coverage, a permanent reference of personalities and trends, and on authentic eye-witness account of events presented in a dramatic manner at a convenient time.
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Before the War, many jobs in American industry were considered "man-sized" positions and therefore . . . for men only. But the War and its tremendous drain on manpower soon gave the female a chance to "strut her scuff." And one such lady, who took full advantage of this opportunity to prove that it wasn't strictly a man's world after all, was Miss Mary Howard, daughter of a well-to-do New England family.

Mary Howard had a flair for good music and records particularly intrigued her. To satisfy her curiosity, she bought a recording machine and started on her own trial-and-error course in record cutting. Miss Howard's interest in recording steadily grew - and so did her recording equipment. And then . . .

Mary Howard came to New York in 1940 and immediately applied for an engineer's job at NBC. As girls weren't being hired for that sort of an assignment, Mary Howard had to be content with a secretary's position in the engineering department. Then, her big break came. NBC, losing man after man to the armed forces, decided, the comely secretary deserved a chance to cut a disc and be paid for doing it. Mary was a big leaguer from this start and in no time at all, the trade looked on her as a master recording engineer.

Her work at NBC gave Mary Howard ideas - big ideas of opening her own recording studio. And just to prove she wasn't day dreaming, Mary Howard invites you to visit her studio (Mary Howard Recordings) at 37 East 49th Street in New York any day you wish.

Since Miss Howard set up her own "shop", a little over two years ago, many of the biggest names in radio have used her facilities. Such outstanding personalities as Alex Templeton, Eddie Duchin, Ethel Waters, Fred Waring, and many others, have come to "Mary Howard Recordings" because they knew that this Howard woman, when it came to making recordings, was "perfection on parade."

"Mary Howard Recordings" functions primarily as a recording service and its operations, besides cutting instantaneous masters, includes line and air checks of all descriptions, studio recording and slidefilm work. In the last year Mary Howard Recordings released their own commercial records. The Herman Chittison Trio, Ethel Waters, Lucille Turner and Dale Belmont are a few of the artists who made recordings under the MHR label. And, like the thousands of other recording companies, Mary Howard Recordings is waiting patiently for the "Petrillo ban" (der amerikanische Musiker Streik von 1941 bis 1943) to be lifted so they can 'get going' again.

Cutting equipment in Mary Howard Recordings, according to Chief Engineer Don Plunkett, Mary Howard's able assistant, consists of: Van Eps and Allied Cutting Lathes, Presto 1-D Heads, driven by Langevin 101 -A Amplifiers.

"Our mixing equipment," Mr. Plunkett explained, "is interchangeable by means of patching. Our Preamps and our program amps are Langevin. Rerecording equipment at MHR," Mr. Plunkett said, "consists of "Allied Transcription Tables" and "Pickering Reproducing Equipment", which have served us most efficiently of all pickups we have tried. This combination - Allied TT's
and Pickering Pickups - we find the most flexible for composite recording."

"Audio Record" asked both Miss Howard and Mr. Plunkett what their particular techniques were - what they did to insure good recordings. To this query. Miss Howard replied: "We are of the opinion that a compact, consolidated recording and control room, combined adjacent to and visible to the studio is the best method of recording. With this setup a recording technician can actually 'ride gain' but what is more important can see what actual level is imposed on the disc.

We feel," Miss Howard continued, "that the term 'riding gain' is a poor description of the operation involved. The more dynamics achieved in a fidelity recording, even if the frequency response is limited, the more the sound originating in the studio will be approximated. We feel that too much emphasis can be put on the word 'fidelity' and that some of the preemphasized and over emphasized high frequencies often result in a sound unpleasant to the ear, which after all is the final judge."

"Dynamic fidelity of course," Mr. Plunkett hastened to add, "is closely allied with surface noise and care must be taken with selection of styli and discs so that low level passages will not be marred (beschädigt) by surface noise.

"And then too," the chief engineer went on, "recording quality must be checked constantly and the best check is immediate playback. This is, unfortunately, quite often ignored by many studios, or discouraged by companies as a waste of time."

"Yes, and," Miss Howard, eager to get back into the discussion added, "recording information about cutting characteristics, recording head designs, styli and quality of response equipment is easily obtained. These all enter into the final results. Unfortunately, the interest and ingenuity of the recordist has often been overlooked. Recording," she continued, "is not a dull craft at all if engaged in all its technical phases. There seems to be a prevalence in large organizations for specialization - cutting technicians, studio technicians, maintenance, etc. - which often results in poor recording because of lack of interest or information in all phases of the recording operation. If interest and enthusiasm were carried all the way through the recording organization, and management, perhaps time might be found to raise the general recording standards in America.

"We have tried," she concluded, "to incorporate these methods (?) in our operation and have had success ... or some such thing."

From what Audio Record has been able to learn, that 'some such thing,' Miss Howard refers to, spells success all right . . . and with a capital 'S'.
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Pat O'Brien Star in Runyon Plays

Damon Runyon's internationally famous tales of Broadway will be dramatized in a series of 52 half-hour recorded programs as the result of an exclusive contract between the National Broadcasting Company's Radio-Recording Division and the Runyon Estate, according to C. Lloyd Egner, vicepresident of the NBC Radio- Recording Division.

Film actor Pat O'Brien will be the star of the radio plays based on Runyon's stories. O'Brien, who will narrate each play as well as enact the role of "Broadway", will be supported in each program by a radio, stage or screen star.

Commenting on the plan, Egner stated, "We of NBC are proud to be associated with Pat O'Brien and the Damon Runyon Estate in the production of this series of half-hour dramatic programs 'The Damon Runyon'. We consider this a significant step forward in the development of syndicated recorded programming, and our decision to introduce this new dramatic feature culminates months of study and experimentation to produce something completely unique and entertaining in the recorded program field."

The series, which Egner described as the biggest and most expensive syndicated recorded program undertaken by the NBC Radio-Recording Division, will be offered on a syndicated basis for spot advertisers over local stations.

Scripts are being written by Tom Langan, veteran radio author and a Radio-Recording Division staff writer, under direction of Gordon Webber, Radio-Recording continuity chief. H. H. Wood, manager of the division's program department, is producing and directing the series. Special music is composed for "The Damon Runyon Theatre" by John Gart. Ed Herlihy will announce.

By C. J. LeBel, Vice President - AUDIO DEVICES, Inc.
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With the rapid growth of FM radio, and its heavy dependence on records and transcriptions, it is time to reappraise our standards of recording quality. As has been found many times in many parts of the audio field, every time the frequency range of a system is increased, other elements in the performance of the system must be improved also. A wide range system will show up excessive noise and unsuspected distortion in most amazing fashion.

Whereas transcriptions were generally listened to (on the ordinary AM radio receiver - das ist immer noch Mittelwelle!) with an upper frequency limit of 4000 to 5000 cycles, on an FM receiver the usual upper frequency limit has been raised to 7000 to 10,000 cycles. Even a few minutes of listening under such conditions will show that, pressings are often not as uniform in quality as their makers believe, for distortion varies from one to the next.
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We will disregard the most easily remedied form of distortion - undesired variation of response with frequency. It is so easy to correct with electrical networks that a recordist with an incorrect response curve has only himself to blame.

Harmonic distortion, of course, is the type which the recordist first thinks of when the word "distortion" is mentioned. It has been a much discussed fault, and certainly should be reduced to a minimum before we worry about more elusive forms. The unit to measure the "minimum" by is not easy to define, however. The rss distortion is a widely used index number, but a poor guide to how objectionable the ear will find the sound. Second harmonic distortion is much less annoying than third, and higher orders are almost intolerable in exceedingly small proportion. This anyone can establish for himself in a few experiments.

Many of us have found numerous cases where harmonic distortion figures provided no guide to the annoyance value. One example the writer recalls, was an experimental recording on wax, which bloomed one humid summer while awaiting processing.

Another example was the distortion measurement being made on an early experimental lacquer formula (die falsche Mischung des Lacks). The sound was not quite right, so the pickup pressure was increased slightly. The 1000 cycle tone cleared up immediately - the improvement was rather great - but the distortion meter reading dropped only imperceptibly. As still another example, Roys has shown' that the audible distortion created by overpolishing a stamper is not reflected in harmonic readings made on the pressings produced by it.

Nevertheless it is quite certain that if the harmonic content is high, we need look no further to explain why listeners are dissatisfied.

If the harmonics are low in value, we may still dislike the sound. In that case the next step would be a measurement of the intermodulation distortion. Whereas harmonic measurement is made with a single input tone, intermodulation testing is a measurement of combination tones produced by injecting a pair of frequencies. This method was first made standard in the film recording field.

We have deliberately omitted any discussion of transient distortion for lack of space. It is a fault not to be ignored, but certainly the industry needs to go further in minimizing better known defects before it worries too much about transient effects.

Intermodulation distortion provides a good explanation of why some recording systems are clean sounding with a single instrument, but fuzz up hopelessly with a full orchestra. Each tone acquires such a multiplicity of sidebands that definition is lost.

The usual test method is to introduce a low frequency tone and a medium or high frequency. Amplitude of the two may be equal, or they may be in a 4:1 ratio. A commercial unit uses 40, 60 or 100 cycles, and 2000, 7000 or 12,000 cycles. Another commercial unit uses these or other tones. Roys' principal work has been done with 400 and 4000 cycles.
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There has been little published work on intermodulation results. Hilliard has very briefly suggested amplifier reproportioning.

On discs themselves, Roys' work' on the effect of overpolishing stampers is of great importance. No other data on disc system or processing characteristics has been published, but unpublished data on a number of the best systems presently in operation show low intermodulation as measured on the lacquer. This is not necessarily true of all systems, nor of all lacquers.

Unpublished measurements by a number of organizations on the effect of processing seem to indicate it as the worst source of trouble. If we are to turn out transcriptions of consistent top quality, some species of control should be adopted. Overpolishing has been condemned for at least a generation, but it still continues.
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It has already been proposed that every master contain a few intermodulation test grooves. These could be used to check every pressing, and thereby the stamper wear. This proposal would certainly eliminate the accidental use of worn out stampers. It would not be a perfect check for overpolishing, as the processor would simply be more careful in the vicinity of the test grooves!

As a supplementary means, it has been suggested that a test pressing from each stamper be sectioned, polished, and measured under the microscope. There is a certain amount of change of groove radius due to compression of the metal of the stamper, but any excess amount would immediately indicate overpolishing. Certainly, some such means will have to be adopted to narrow the quality difference between the lacquer original and the pressing.

References
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• 1. H. E. ROYS. Inlermodulalion Dinortitm Analysis as Applied to Disc Recording and Reproducing Equipment. Proc. I.R.E.. vol. 35. no. 10, 1149-1132. October 1947.
• 2. J. K. MILLIARD. Intermodulation Tests for Comparison of Beam and Triode Tubes Used to Drive Loudspeakers. Communications, vol. 26, ni pp. 1317. 34. February 1946.
• 3. J. K. MILLIARD. Distortion Tests by the Intermodulation Method. Proc. J.R.E., vol. 29. no pp. 614-620. December 1941.

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Research Director Franck Introduces Staff to Audio Record Readers

It wasn't long after the first Audiodiscs were made, hack in the late thirties, that Audio Devices realized the importance of, and the need for, a fully-equipped and fully-staffed Research Department. "To progress, one must explore" was the philosophy of William Speed, Audio's president, and soon the young company was laying plans for what is now, possibly, the most modern, up-to-the-minute research depart ment in the recording disc field.

One of the very first steps in creating such a department in any company, of course, is the hiring of an outstanding man, who not only possesses the ability to delve deep into the unknown qualities of your product and its competitors, but a man, who can mold together a fine staff of capable and creative assistants who will work as a "team" to further the progress of your organization. The Research Director that Audio Devices engaged to set up their Research Department had all of these qualifications ... and more.
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And Ernest W. Franck has justified his company's choice time and time again. Ernie Franck has been a well-known figure in the sound recording field since almost its infancy. Considered an authority on the art, he is not only a demon for work but an inspiration to others working with him. Ernie Franck is not a desk executive, not by any means. He is "right in there" with the boys on every project, on every problem.

Besides his vast (unermesslich) knowledge of discs, their components, etc.. Audio's Research Director, it is safe to say, knows as much, or more, about magnetic recording tape as any man in the country. Actively engaged at the present time in furthering Audio's development work with Audiotape, Mr. Franck spends countless hours exploring into the possibilities of this new sound recording medium.

In assembling his staff of chemists, technicians and so on, Mr. Franck has taken time to "be sure" in his selections. Each time an addition was made, the "Franck Stamp of Approval" usually guaranteed a sound and profitable investment to Audio Devices. Believing in the theory that only "interested" workers make good researchers, Ernest Franck is justly proud of his six-man staff. Ernie would like Audio Record readers to know these men, so we take pleasure in introducing them here ....

George M. Sutheim (#3 in photos on Page 1). Mr. Sutheim is Chief Chemist at Audio. A graduate (Chemical Engineering) of the Institute of Technology in Vienna (Wien !), he is a chemist of long standing in the field of varnishes, lacquers and emulsions. From a chemical standpoint, Mr. Sutheim rigidly controls the components that go into each and every Audiodisc. Improved formulation of Audiodisc coating is always on his agenda. Authored "The Introduction of Emulsions" and contributed to Dr. J. J. Mattiello's "Protective and Decorative Coating". Also author of many articles on coatings and film, etc. in both
French and English periodicals.

Harold J. (Andy) Southcomb (#1 in photos). Andy (as he is affectionately known to his co-workers) Southcomb's contribution to Audio Research is his wealth of knowledge of phonograph records, materials, techniques, etc. Formerly with RCA Victor and Decca Records, Mr. Southcomb is currently working on special products at Audio, including magnetic tape, etc. His experience in the field of paper, plastics and adhesives makes him a particularly valuable man in this development work.

Stephen Schettini (#4). Steve Schettini, it can be said, would be lost without the Research Department gang, but not half as lost as they would be without him. For Steve carries a mighty big load for Ernest Franck and Company. You might, and you should, call him an experimental machinist and technician. Mr. Schettini is responsible for the construction of special equipment used in the department's experimental work. Steve has the ability to interpret someone's idea and put it into a physical reality. For example, if the Research Director wants to test a particular material and needs a special device to accomplish this end, Steve retires to his special workshop and designs and builds the contraption. Also, Mr. Schettini has been involved with the magnetic tape development.

Frank Radocy (#5). Former Captain in the Army Air Corp., Frank Radocy is in charge of the department's production activities. Responsible for lacquer formulation on production basis. Frank makes up special formulation cards on a batch-by-batch basis. Also, he is doing magnetic tape production, being responsible for individual cards on each tape lacquer batch and the mechanical operations necessary for them.

David S. Gibson (#6). Thirty one year old Dave Gibson is a recording lacquer specialist. His work in the department, besides lacquer experimental formulation and quality control, includes styli and groove shape studies as well as special development work. In the recording lacquer end, Dave in addition to testing the lacquer coated discs on a turntable, also makes humidity tests to determine how well the lacquer holds up under varying temperatures and humidity. In these recording tests both styli and grooves sections are examined with a special projection microscope which magnifies five hundred times. Additional playing tests are also made for surface noise and wear.

Allison B. Randolph (#7). A radio technician, Mr. Randolph has had a number of years experience in the technical end of radio. He is the maintenance man on all electronic equipment in the laboratory.

That's it. That's Ernest Franck's Research Department line-up. And a qualified crew it is, too.
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Record Number of Radio Engineering Exhibits; 183 Firms to Participate

Tremendous interest in "Radio-Electronic Frontiers", which is the timely theme of the 1948 I.R.E. National Convention, is proven by the vigorous increases in both numbers of exhibitors in the Radio Engineering Show, and the space taken in three floors of Grand Central Palace's huge exhibition area. The Show opens Monday, March 22 nd, and runs four days through March 25th.

One hundred eighty-three of the headline firms of radio and electronics are participating in the Show with displays ranging from single booths to areas large enough to duplicate an entire transmitting studio. The latest developments in instruments, components and complete transmitters will be shown. Every phase of electronics and communication equipment, and some of the latest methods of aircraft guidance will be presented to the 10,000 radio engineers coming to the convention from every part of North America. For the first time, 22 exhibits will be placed on the third floor, adjacent to session halls for technical papers. Exhibit space is 30% ahead of 1947.

More than 120 technical papers, skillfully organized in 28 related sessions will comprise the lecture program of the convention. Three social events, a cocktail party, Monday; the popular President's Luncheon on Tuesday, and the Annual I.R.E. Banquet on Wednesday Evenings add color to what has grown to be one of the world's greatest assembly of engineers.

Audio Devices will display its products in Booth #233.

By C. J. LeBel, Vice President - AUDIO DEVICES, Inc.

Recent correspondence has made it apparent, that many of our readers are not in touch with phonograph record manufacturing methods of today, but would like to know more about the subject. We will sketch a typical procedure, without attempting to cover every possible variation. It will be found, that the durability and permanence of lacquer recordings have permitted many changes from methods of the old wax days. The NAB standard terminology (*1) will be used where it fits in.
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The selection is recorded by usual methods on a lacquer disc. This is often done on a 16" blank, so that several takes may be recorded on a single disc.
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The best take is selected for processing. This take is re-recorded by conventional methods on to the correct size master disc for the pressing to be made: 12" for a 10" pressing, 13 1/4" for a 12" pressing. The eccentric circle common to most phonograph records must also be cut. The final result is known as a lacquer mother.
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The lacquer surface is coated with a conductive film of metal by either chemical deposition of silver (silvering) or by electrical discharge deposition of gold in vacuum (gold sputtering). Avery difficult problem which we had to solve in formulating our lacquer was to make it take silvering and sputtering with consistently good quality. A heavy layer of copper is plated on top of the conductive layer by conventional electroplating procedure. The result, stripped off the mother by mechanical means, is known as a shell stamper, and if attached to a heavy sheet of backing material becomes a backed stamper.

The stamper center hole is bored out concentric with the grooves, the rim is trimmed to size (removing the oversize portion, often marked by plating clamps), and it is then ready to be used. In many cases it may be given a flash layer of chromium to enable it to better withstand the wear and tear of use.

A lacquer mother may be coated, electroplated, and stripped several times, producing an equal number of stampers.

One operation can seriously injure quality : polishing. It has been claimed that the dirt adhering to a stamper may be removed by a high pressure jet of clean air, but it has been customary to use more drastic means. Emory Cook has shown that even a heavy rub with a rag is enough to polish off all traces of 25 kc. H.E. Roys has shown (*2) that overpolishing can introduce serious intermodulation distortion. In any case, there has been steady disagreement between recording room and processing department on the tendency to overpolish, for many years.

The stamper is then fastened to a record die on one platen of a molding press, and another platen is fastened to a record die on the other platen. Labels are placed at the centers. Steam is passed through the record dies, a hot biscuit of pressing stock is placed on the lower stamper, and the platens are closed under pressure. Shortly thereafter the flow of steam is cut off and cold water is circulated thru the dies. When the disc is cool and hard, the press is opened and the pressing is removed. The edge is trimmed and the record is then ready for shipment.

The interesting thing to note is that the process of going from the original recording to the mother is done electronically rather than electrochemically. The saving in time, if enough mothers are needed, may amount to several days.

References
1. GLOSSARY OF DISC RECORDING TERMS. Audio Record: Feb. March. May. June. July 1946.
2. H. E. Roys. Intermodulation Analysis as Applied to Disc Recording and Reproducing Equipment. Proc. I.R.E. vol. 35. no. 10, pp. 1149-l152. October 1947.

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By Ray Richmond in April, 1948

Pancake flour and pancake make-up, Ronald Colman, horoscopes, the California Chamber of Commerce, and cough drops bestow their largest of entertainment and education on the American public by transcription every day. What better way to reach the people? None. Then why not instruct concerning humanitarianism in the same tried and true way? Red Cross does. And who but Red Cross has its finger closer to the pulse of the populace? No other; not even the Gallop Poll.

Always needed, always there, the National Red Cross is asking for 15 million dollars more this year than last. Remember the Texas City disaster; the floods in the Midwestern States; and the forest fires in New England? Not counting the hundreds of smaller calamities that never hit the front pages. Millions of victims were cared for, and this kind of Brotherhood costs money. Hard working, honestly devoted volunteers are only biped. They can reach but a small group of us. Radio reaches more people more easily.
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To appeal to this large audience for the Red Cross 1948 Fund, six 15-minute capsule versions of top network radio shows were prepared on discs in the format of their regular weekly features. These shows star Bob Hope, Bing Crosby, Dick Haymes, Frank Sinatra, Jack Benny and Kay Kyser, but they include "Red Cross Commercials'" as inserts instead of the usual sponsor plugs. During March, the traditional Red Cross Month, these recordings were played on more than 1,000 stations in the United States.

Also, four-and-a-half minute dramatized spots featuring screen stars Ella Raines, Robert Montgomery and William Bendix will be heard during the 1948 Fund Drive with eight 45-second straight announcements by Hollywood "name" announcers on the reverse side of these two-sided transcriptions.

There is still another use for Red Cross recordings. Mutual Broadcasting System used a portable recorder to record the inaugural Manhattan campaign luncheon at the Waldorf-Astoria in New York on February 13, at which Bop Hope was one of the principle speakers. To the listening audience that night, the network played back a part of the Hope speech on its Radio Newsreel program.

An additional project to be initiated by the Red Cross this year will be the collection and processing of 3,700,000 pints of blood for the 65% of the hospitals in the country who are in no position to supply blood plasma needed in emergencies. This, too, will cost money. John Public must underwrite his own future.

If the past experience of the Red Cross is any indication, however, the American people will again generously respond to the call of these potent platters, for funds and for volunteers for its many services. Yes, Red Cross knows the true value of the recorded appeal.

The 1948 National Convention and Show of the Institute of Radio Engineers, held March 22-25 in New York's Grand Central Palace and Hotel Commodore, was the most successful venture in the Institute's history, I.R.E. officials advise. During the four day meeting, approximately 15,000 persons registered and viewed the show's 190 exhibits - one of which was the Audio Devices' booth (above) displaying the various types of Audiodiscs, their applications, and each step necessary in their production from raw material to finished blank; and the process involved in making phonograph records from Master discs.

In addition, engineers stopping at the Audio booth got a glimpse of the company's latest contribution to the sound recording field, magnetic-oxide Audiotape.

But perhaps the most interesting part of the Audio exhibit were the history-making recordings lined on the booth's sidewalls. Cut on Audiodiscs during the last ten years (Audio celebrates their 10th anniversary this year) these recordings featured, among others, the following important nation-wide broadcasts: Attack on Pearl Harbor, President Roosevelt's speech in French on North Africa landing, D-Day, Radar to the Moon, Secretary Marshall's "Voice of America" address, and President Truman's recent message to Congress. (This exhibit will also be seen at the Radio Parts Show in Chicago May 11-14 in Booth #83).

Several months ago, Audio Record ran a story on the operations of what its owner claimed to be, "the smallest recording studio in the United States" (after viewing a photograph of the establishment it was impossible to dispute this gentleman's word). So now, we believe it only fitting, that we feature an article on the largest recording studio (under one roof) in this country.

This distinction belongs to Nola Studios, located at 1657 Broadway in New York City, where some forty orchestras have been known to rehearse and record during a twenty four hour period. The fourteen individual studios that comprises Nola Studios covers an area of 20,000 square feet.

Nola Studios is owned and operated by one of the true pioneers in the recording field, Vincent Nola. Vincent Nola was born in Sicily in 1895 and 10 years later, with his family, moved to the United States and to a home in Buffalo, New York. It was in Buffalo that Vincent got his start in the musical world. With pennies saved from a paper route, he studied voice under the tutelage of well-known Buffalo and, later, New York teachers.

Young Nola's first professional singing job was in Niagara Falls (he doesn't remember just where in Niagara Falls or just what he did besides sing) at the age of 16. Later, in between professional engagements, Nola taught voice in New York City. Then, Vincent Nola got an idea.

Vincent Nola's idea was to open a large rehearsal studio in New York for bands and other large musical groups. Up to this time, a studio of this type was unheard of. In 1930, Nola put his idea to work when he rented several large rooms in Steinway Hall. Within eight months he had eight studios in this famous old building and many of the top talent of the day were using his facilities. Then Nola got another idea. Why not equip some of these studios with recording equipment so the "big names" could put their renditions on
record.

Nola, at this time, knew nothing at all about the engineering aspect of sound recording. But he decided to learn. Nola studied hard, day and night, for three months acquainting himself with the art under the guidance of one of CBS's most talented engineers. Then, after he felt he knew something about the recording business he opened two recording studios in the same Steinway Hall. This was in 1934.

The operation was a success from the start and in the years that followed the Nola Studios became a "by-word" with famous popular and classical music artists, "name" bands and other musical aggregations. Both as a rehearsal studio and as a recording studio Nola's became more popular as the years went by. In fact, too popular, with the big bands. For in 1940, the management of Steinway Hall decided that Nola's clients, the fifty and sixty piece variety, were making too much noise for the conservative residents of 57th Street. Nola would have to move.

But Vincent Nola solved the problem by opening the present Broadway studios for his "noise makers" and keeping his 57th Street location open for his less disturbing or "long hair" clientele (opera singers, concert pianists, etc.). This arrangement proved a good move and even today the bands still use the Broadway studios.

Then, as now, seventy-five percent of Nola Studios recording work is done for music publishers for "song plugging" purposes. But in addition such outstanding orchestras as Bob Crosby, Art Mooney, the Dorsey Brothers, Xavier Cugat, Benny Goodman, Frankie Carle, Raymond Scott and Charlie Barnett have used the Nola Studios for their rehearsal and recording sessions.

The secret of Vincent Nola's success in the recording field probably lies in the fact that all six of his recording engineers possess a musical background. As a matter of fact, Nola himself has taught each of these engineers his particular techniques so that they record from the 'musician's' not the 'professional recordists' point-of-view. As Vincent Nola explains it: "the average listener wants to hear something pleasing to the ear from a musical standpoint. He is not remotely interested in the technical phases involved." All told, Nola employs sixteen people in his two studios.

Naturally, Vincent Nola is as interested in the outcome of the present recording ban edict as everyone else in the business. When asked what his thoughts were on the matter, Mr. Nola smiled and said: "well, I hope a solution will soon be found that will make us all happy. Yes, I mean Mr. Petrillo, too".
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• Anmerkung : Weiter oben wird von dem "Petrillo ban", dem Streik der Musiker berichtet.

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Net To Use Tape Recorder For DST Operations; Lower Costs - Improved Program Fidelity Is Anticipated

A noticeable improvement in quality of rebroadcast programs and a substantial reduction in costs to Its affiliated stations is anticipated when the American Broadcasting Company sets in motion its vast plan for Daylight Saving Time Operations on Sunday, April 25.

Operating only during the 22 weeks of Daylight Saving Time, the plan which ABC initiated in 1946 and expanded last year to the network's full program schedule, through the use of special broadcast zones and recordings maintains all ABC programs in all time zones at the same time the year round.

Improved program quality and lower costs to ABC affiliates stem from the fact that the web this year plans to use "Ampex Electric Corporation's" tape recording machines to record its entire program schedule for playback directly from the tape. The machines are based on designs and specifications prepared by ABC engineers. The machines also are expected to be used yearround for all regional repeat broadcasts by the American network.

• Anmerkung : Hier werden im April 1948 (erstmals) die ersten Ampex 200 Magnetband- Recorder erwähnt, die Bing Crosby für seine Show bei AMPEX in Auftrag gegeben hatte.

This will mark the first time in radio history that a network program has been rebroadcast directly from a recording tape. Heretofor, programs that have been recorded on tape were transferred to recording discs and then broadcast.

• Anmerkung : Laut Jack Mullin trauten die ABC Techniker auch dem Ampex/3M Magnetband nicht über den Weg, weil die Firma Brush Development mit ihren Geräten immer wieder für einen Ausfall mit dem bei denen verwendeten Papierband gesorgt hatte.

ABC, during the past two years that it has been using its special plan of Daylight Saving Time operations, has utilized disc recordings to play broadcasts back at their accustomed time to local audiences.
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Based on engineering tests conducted earlier this year, which indicate a noticeable improvement in program quality and tone fidelity through use of the Ampex tape recorders, ABC has placed an initial order for 12 of the machines and delivery is expected shortly.

• Anmerkung : Diese Tests wurden mit den deutschen AEG K4 von Jack Mullin in den ABC Studios durchgeführt. Dennoch vertraute man dieser "deutschen" Technik nicht.

Savings anticipated by ABC from lower operating costs through use of tape recorders and the direct play-back of programs from these machines will be passed along to the networks affiliated stations which share in the cost of the Daylight Saving Time plan.

Basic mechanics of ABC's Daylight Saving Time plan of operations, developed by the network through the cooperation of its clients and affiliated stations involves the acquisition of special broadcast lines by ABC. Through the use of these special broadcast lines, programs are broadcast live to ABC stations operating on Daylight Saving Time and recorded in Chicago and Hollywood for rebroadcast one hour later for stations operating on Standard Time.

The recorded plan is used only on ABC's regularly scheduled programs. Special events, such as a Presidential speech, a major prize fight or the coverage of conventions, etc., will be heard at the time they take place.

By C. J. LeBel, Vice President - AUDIO DEVICES, Inc.

We have had a large number of inquiries on the comparative merits of disc and magnetic recording for professional use, and, since we make media for both methods, a preliminary survey has seemed desirable. Unfortunately, at the present stage of the art the answer seems to be more in terms of the associated equipment's limitations than that of the medium itself.
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• Anmerkung : Aus den nachfolgenden Statements kommt heraus, selbst der 2. Chef von Audio Devices hatte im April 1948 noch fast keine Ahnung, womit sich seine Forscher, die er im darüberliegenden Artikel so toll beschreibt und lobt, beschäftigen. Auch wurde weiter oben beschrieben, daß sich Audio Device solch einen Taprecorder zugelegt habe. Aus diesem Artikel mit dieser Menge an falschen Aussagen entpuppt sich das als Wunschdenken, einen Recoder anzuschaffen. Zu allererst wird das Produkt Schallplatte gegenüber dem Tape in den Himmel gehoben und das war aber genau umgekehrt.

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Tape is easy to edit with scissors and a roll of adhesive tape. This is one of the
reasons why it has replaced (steel-) wire for professional magnetic recording, for wire splicing is neither convenient nor durable. For example, for shortening the record of a political convention from eight hours down to thirty minutes there is nothing as good as tape.

Tape can be erased and reused, and for the programs incident to daylight saving time adjustments, programs mainly of transitory value, this is a real feature. Programs can be "assembled" on tape.

Recording on tape requires less mechanical skill than does disc, for there are no
styli to wear out and replace. Editing requires very great skill. On the other hand, magnetic recording heads wear and lose quality - so that head wear-tests and replacements become necessary.

In reproducing, the mechanical skill for disc is negligible, but tape requires care and attention for correct threading in many machines. Tape may break in starting, and splices may pull apart in reproducing or rewinding. Such a failure may create a veritable "bird's nest", and if during reproduction can ruin a program. This may be one reason, why the BBC for years has rerecorded from tape onto disc for program use.

• Anmerkung : Das ist leider ziemlicher Unsinn, die BBC hatte bis 1946 keine Magnetbandgeräte, sondern die Stille-Stahlbandmaschinen im Einsatz.

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The factors governing the durability of lacquer discs are well understood. Lacquer
will be comfortable under any condition where a man will be normally comfortable.
However, little is known about tape, particularly under exacting professional standards of performance. Severe dropping, heavy vibration, or exposure to strong magnetic fields can cause erasure, noise and distortion increase.

Magnetic fields are invisible, and not noticed unless strong enough to affect a watch. All magnets lose magnetization strength with time ( das ist Unsinn), and so we would expect tape recordings to change with time. Whether they will simply grow weaker, or whether the strongly magnetized portion will fade faster than the weakly magnetized (producing distortion) is something that no one can presently answer with certainty.

• Anmerkung : Sie wußten es damals nicht besser, und darum wird hier mit Vermutungen argumentiert. Das Gegenteil konnte erst so um 1949 von Forschern an den amerikanischen Unis und Instituten bewiesen werden. Der Spruch : "Alle Magnete verlieren Ihre Kraft mit der Zeit." war damals eine reine Hypothese (oder Schutzbehauptung).

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It must also be remembered that scratching of the tape will deform the coating, and hence create distortion. Conditions affecting the base material are not too perfectly understood, either. Shrinkage due to age or atmospheric conditions can spoil accurate timing, and change the musical pitch quite detectably. Excessive reproducing machine tension can stretch the tape, with equally bad results.

We can be reasonably certain of the sustained strength of a plastic base, but
not of a paper base. Paper used today is generally made from wood pulp, whereas older paper was generally made from rag stock. We have only to look at newspapers a few years old to realize that the life of a wood pulp paper is not too long.

At professional tape speeds, programs can he filed away more compactly on disc than on tape, for a half hour on disc requires 10 cubic inches, while a half hour on tape at 30" per second requires about 35 cubic inches. Also, a disc can be replayed immediately after, or even during recording, while tape requires an appreciable time to rewind or spot.

Finally, facilities for playing tape are by no means as plentiful as those for disc. Nor do we yet have standardization on the all important matter of tape speed. In common use today we have the following: 7 1/2, 15, 18, and 30 inches per second.

This has special significance to the educator, for speech correction and dramatic work have been helped greatly by the motivation afforded by a chance to take a disc home. The educator will wish to use a tape speed of at least 15 inches per second to get fidelity adequate for educational purposes - but such few machines as his students may have at home will undoubtedly be limited to 7 1/2 inches per second.

The professional will be bothered by this situation as soon as he begins to ship tape recordings to various parts of the country.
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The frequency response of a recording medium is a hard thing to evaluate, for it depends so heavily on conditions of operation and on associated equipment, that in the case of lacquer no upper frequency limit for the material itself has yet been found.

Up to a short time ago, (bis vor einiger Zeit) the cutting head constituted the chief limitation on frequency response, but the advent of units using the head as part of a negative feedback loop - "feedback cutters" - has removed this obstacle, and recording in the supersonic region has been so made.

Smaller radius recording and reproducing styli are, of course, desirable to reduce tracking loss at very high frequencies when working at normal rotational speed (gemeint ist 78 round per minute), but test has indicated that our lacquer is strong enough to be entirely satisfactory at such higher needle pressures. It may also be desirable to reduce the length of the burnishing facet of the cutting styli.

• Anmerkung : Hier der erste Verweis auf eine mögliche neue "microgroove", die Mikrorille mit der deutlich dünneren Nadelsitze bzw. Verrundung.

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The frequency response of tape is limited, basically, by the tape speed and by the minimum attainable slit width (Spaltbreite) in the recording and reproducing heads. The latter presently stands at about 3/4 mil. physical width, but the effective magnetic width, considering fringing, is not the same. The slit width limitation can be overcome by running the tape at higher speed, but this raises the cost and operating problems.

Distortion is also a hard problem to evaluate. In disc recording the chief bottleneck used to be the cutting head, but the newest cutting heads are so good in this respect that the present distortion limit is set by approximately equal contributions from the recording and reproducing amplifiers, the cutting head and the pickup. We have not yet produced systems so free from distortion that lacquer distortion, if any, becomes a factor.

On tape we also have recording and reproducing heads, recording and reproducing amplifiers, but the recording medium itself definitely is a factor. Since the bias for minimum distortion depends on frequency and on level, optimum bias is a compromise. It is not easy to pick a distortion value which everyone would agree on as representative. A comparison of disc and tape is further complicated by the fact that disc system distortion drops rapidly as levels are reduced below maximum, while tape distortion (depending on the bias chosen) may even increase. We have to accept intermodulation distortion figures cited as representative by those engaged in these fields, on which basis disc is somewhat better than tape. Whether it will remain so is a question, of course.
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We are inclined (sind geneigt)to feel that it will, for this reason :
The electromagnetic part of a system operating at high level is likely to be the part creating the worst distortion. In a disc system, this would be the cutting head, but we have already succeeded in reducing cutting head distortion by including the head in a negative feedback loop. On the other hand, we can see no present way of including the tape itself within an effective feedback loop! It would appear, therefore, that there should be an inherent difference between the two systems, though possibly a small one.

We have not touched on tracking distortion in disc reproduction. This, the failure of the reproducing stylus to follow the groove faithfully, exists only at peak levels at high frequencies, and can be reduced to insignificance by using sufficiently small radii on recording and reproducing styli. In short, with intelligent engineering such distortion occurs only at overload - exactly as tape can be overloaded with ensuing complete distortion.

Signal to noise ratio, judging by ear, is fairly similar for both media, though both depend heavily on equipment perfection for best results. Some of the early postwar figures out of Germany suggested fantastically good ratios for tape, but it was soon found that these were weighted figures.

American practice is to use unweighted noise data, whence the initial misunderstanding. If we compare practical equipment under practical conditions, we find that the ratios, on a weighted basis, are not greatly different.
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Tape has a curious defect which does not show up in ordinary methods of measurement, yet which is rather important. This is undersignal noise, which can be best described as noise cyclically modulated in intensity by the signal. It has had only a limited amount of attention because present methods of determination are very laborious, yet the figures so far presented are not to be ignored. The ear does not hear such undersignal noise as noise, rather does it consider it as a kind of fuzz on the tone. In short, the ear is as annoyed by it as by intermodulation, and it exists at all signal levels. The analogous (but not identical) defect on disc can occur only at the extremely high peaklevels used in some phonograph recording. Cook, who first discovered this effect on disc, has shown that by the proper design of cutting stylus the effect may be reduced to insignificance even at phonograph recording peak levels. In any case, it is not existent at transcription recording levels, or at average phonograph levels.

Tape is an instantaneous recording medium, just as is lacquer. Hence we have to compare them on that basis; i.e., both have to be individually recorded. Likewise,
either could be rerecorded onto a processing size lacquer blank, and duplicated as pressings. In so doing, of course, distortion and signal-to-noise-ratio would suffer. Some comparisons have been made between tape and pressings. This is not valid, because an instantaneous material like tape has to be duplicated by rerecording, a high cost process.

We are sorry to have to say "it all depends" so often, but both disc and tape are
going through a quality revolution, and it will be hard to issue any publishable figures until affairs stabilize. In the meantime, we would be disposed to view much of the material published on tape as too superficial. A great many more studies will be necessary before we fully understand the vagaries (verrückten Einfälle) of the medium. To uncritically assume that a new medium can have no faults is to treat the matter as a layman rather than as an engineer.
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By C. J. LeBel, Vice President - AUDIO DEVICES, Inc.

In response to a considerable number of inquiries on specifications for our AUDIO- POINTS, we are presenting for the first time complete dimensional data. Quality control of cutting points was discussed in a previous issue.
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Unique among presently available recording styli, our # 14 is made with a biased front surface. It will be recalled that the old wax recording stylus was cemented in place, and the recordist would rotate it slightly in its mounting to get the thread to clear the groove reliably. There was a knack to it. Another way of achieving the same end was to move the cutting head (in its cradle) forward of the center line, which nearly has the same effect (though at the expense of distortion increase which does not occur if the point, rather than point and head, IS biased).

When we started supplying AUDIO-POINTS wc traced occasional thread snarls to the cutting point standards of the day. The sapphire's front face was nominally exactly parallel to the flat on the dural shank (i.e., a bias of 0°), but a variation
of ±1° was possible. ±1° styli (i.e., in a direction to throw inward) would throw the thread toward the center very nicely, but in a 1° stylus the natural thread action inward would be opposed by the point tendency to throw outward. The result would be very erratic, with no certainty of thread action, and an excellent chance for a tangle. We built a special measuring microscope, which many visitors to our laboratories have seen, and definitely established the correlation between bias and thread action. By designing for 3°, a manufacturing variation of ±1° can never reduce the bias to the point where thread action becomes erratic.

Some recordists used to use round shank sapphires to allow the same possibility of adjustment that the wax recordist had with his cemented-in point. This practice became obsolete the moment biased points became available. Other recordists used to shim out one side of their cutting heads to attempt to produce the same effect. A moment's reflection will show that we have biased recording head as well as point edge.

The plane of cutting motion is then no longer straight across the groove, in fact a forward and back component is introduced. This is distortion, and cannot be permitted. The biased point is hence definitely superior to the biased recording head.

Doch diese Tabellen der 78 Nadeln interessieren heute wirklich nicht mehr. Ich habe sie nicht dargestellt.

Sapphire Cutting Styli
hier kommt eine Tabelle

Inspecting this data, we find that the No. 202 is a lower cost unit, and that the sapphire length is shorter than in the No. 14. It should also be pointed out that the No. 14, being made to professional standards, is held to closer tolerances than is the No. 202. Incidentally, 70° styli are now virtually obsolete.

The difference in shank material is necessary to mark these differences in characteristics for the shop and the dealer.

The burnishing facet is all important. Since it is the final manufacturing process, it must affect the final contour of the functional part of the stylus. The resultant dimensions will therefore vary from those listed above, within practical limits.

Stellite Cutting Stylus
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Being still lower in cost, the radius is not held to as close tolerance, but is maintained at a value low enough to insure that playback stylus will track on the straight the sides of the groove (insuring good tracking) .

Steel Cutting Stylus
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This is a diamond lapped point; it should not be confused with points which are ground but not lapped, and hence are much noisier.

Sapphire Reproducing Styli
hier kommt eine Tabelle

The significant differences are the change in length of sapphire, and the tip radius. The included angle and shank length changes are only to mark the difference in unmistakable fashion for the shop.

The professional No. 113 has a sapphire length several times as great as that of the lower cost No. 103 and 303.

The professional tip has a radius of .0023", well adapted to transcription grooves. On the other hand, for home phonograph records the larger radius of .0025" is preferable. While there has been considerable advocacy of .003" tips for home reproduction, we do not agree. A .003" tip is initially very slightly quieter, but the noise quickly exceeds that of the smaller radius, and coincidentally the distortion and record wear increase. The differences can be credited to the better tracking of the smaller radius. A point which follows the groove faithfully will cause less wear than one which cannot trace the finer convolutions. Hence we have chosen the .0025" radius.

It should be pointed out that all of these styli can be resharpened when worn out playing pressings. This is a real economy, for resharpening is much lower in cost than a completely new needle. This has been made possible by using a longer gem (than is customary for home points) in the 103 and 303.
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When the NAB and RMA committees now working adopt standards, these specifications will be changed to conform if necessary. It is believed that present points will work satisfactorily with proposed standards, and in many cases will require no change at all to conform. In any case they can be modified to conform when sent in for resharpening.

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