Broadcasting Telecasting (Jan - Mar 1951)

A New TV Art TELEVISION, itself new, is adopting a new audio art to achieve both better quality and lower cost. This new art is magnetic sound recording. Its use in making television films has saved countless thousands of dollars, yet improved audio quality — and still bigger savings and better quality can be expected. Those benefits, now enjoyed primarily at network headquarters, can also be expected at individual TV stations. Magnetic recording applies to any television film, from filming local programs and commercials to filming live action that is to be sent to other stations. Television approached magnetic recording gingerly at first, seeking economies. By DANIEL E. DENHAM NEW YORK TECHNICAL SALES REPRESENTATIVE MINNESOTA MINING & MFG. CO. First step was to switch from optical film to magnetic tape in making the duplicate or "safety" sound master. This reduced costs sharply, since the magnetic "safety" could be erased and reused repeatedly after the film was completed. Savings ran into tens of thousands of dollars in the New York area in the first few months. Another advantage was realized at the same time — 'the magnetic "safety" could be played back immediately. This speeded production and saved additional thousands of dollars. Since the producer could play back the audio section immediately, he could make correc % a • Q % a TV STATIONS hove been quick to adopt the new method of magnetic sound recording, Mr. Denham says. Above are two of the Fairchild Pic Sync magnetic recorders installed at the CBS television studios in New York. At left is an RCA 16mm magnetic film recorder used in NBC's New York TV studios. tions on the spot instead of having to do it later when it would require reassembling an expensive cast and set. TV stations have been quick to adopt the new method: CBS with Fairchild magnetic tape equipment: NBC with RCA 16mm magnetic film equipment; and DuMont and New York' City's Television Unit, with Reevesound 16mm magnetic film equipment. After magnetic recording had effectively cut costs, television began considering its other virtue — quality — and adopted magnetic tape or film for the master as well as the "safety." Mixing the various tracks (dialogue, background music, etc.) was all done on the magnetic medium, and the completed audio master was magnetic. Quality was improved, since the magnetic medium retains its original quality throughout processing, while the optical system suffers several losses in quality. Better Quality With this method, the finished product is still a composite picturefilm-and-optical-recording, but the quality is better, and costs ' are lower since the magnetic material can be re-used. However, the method that gives the best audio quality and lowest cost is the "dual system," which uses the magnetic medium both for recording and for playing back. Safeties and masters are made on magnetic, with mixing and dubbing also on magnetic, thus the finished audio product is a complete master magnetic film or tape. This is played back in a magnetic playback unit in synchronism with a separate picture film projector. A better picture image is also obtained, since the picture processing steps are cut down, thus eliminating imperfections created by those steps. A negative print is used. And costs are still further reduced due to the fewer *film processing steps. LATEST technical improvements in the ever developing art of television usually are translated into savings for the telecaster and better service for the viewer. Daniel E. Denham, an authority on magnetic sound recording for TV, herewith points up its advantages to station operaMr. Denham is the New York Mr. Denham tors. technical sales representative for the Minnesota Mining & Mfg. Co. of St. Paul, maker of "Scotch" sound recording tape and film. [Two definitions may be in order: Magnetic film, is of 16mm, 17%mm, or 35mm width; has a 5-mil cellulose acetate base similar to motion picture film; has a coating or iron oxide instead of an emulsion; and is perforated, with the sprocket holes being the same pitch and width as those in picture film. Magnetic tape is Vt" wide, has a base thickness of IV2 mils, and is coated with iron oxide similar to the magnetic film, but has no sprocket holes.! In the "dual system" of using a magnetic medium for playback, the major problem that television encountered was lip synchronization. It was also the only important problem, since other questions — fidelity, signal-to-noise ratio, amplitude variation, level, storage conditions etc. — had been proved through radio use of magnetic tape and film. Sprocket holed magnetic film seemed the obvious way to achieve perfect synchronization between sound and lip movements. A recorder, using magnetic film and run by a synchronous motor (fed from the same line source as the synchronous motor of the picture film), stays in perfect lip synchronism. The two machines are locked in synchronism at the start of the take, and stay that way throughout the take. The operation (Continued on page 70) Telecasting • BROADCA STING