Journal of the Society of Motion Picture and Television Engineers (1950-1954)

the two distortion products are combined, they will cancel each other. This results in reproduced sound free from cross-modulation distortion due to image spread. It is now possible to produce such recordings at a density of 1.80 with a cross-modulation cancellation of 40 db as compared to a density of 1 .0 without the use of this device. The magnetic transfer machine, illustrated in Fig. 2, was also developed by RCA and placed in operation at the Warner Bros. Studios during 1 952. This reproducing machine was developed specifically for transferring magnetic material such as production dialogue and music scoring to another record. It is capable of reproducing both 17|-mm single-track film operating at 45 fpm and 35mm three-track film operating at 90 fpm. A unique feature is the ability to transport film from reel to reel at four times the respective operating speeds without removing the films from their driving sprockets. This makes for rapid selection of "ok'd" takes which are to be transferred to another record. Additionally, high-speed rewinding directly from reel to reel at approximately ten times the normal operating speeds is provided. The savings in operating cost due to the use of this equipment make it a worthy contribution to the art of soundfilm recording. During 1952, the Paramount Sound Department built and placed in use a magnetic-to-magnetic transfer reproducer-recorder, designed to speed up the transfer of sound effects and short dialogue sequences for editing. The film is transported on plastic belts which also hold the film "wrapped" on the reproduce and record heads. Sprocketless and requiring no loading leader, the films are up to recording speed in a small fraction of a second. The reproduce and record belts are driven from a common shaft causing starting flutter to be comparative and not heard in subsequent reproduction. The transferred film is in linear syn chronism with the original. Sprockethole pitch variations may alter exact synchronism but within the limits for this type of service. Loading is simple and encourages the use of film "short-ends." A similar device is in use at Ryder 16mm Services for the re-recording reproduction of sound effects loops. Quick loading and unloading of loops is possible while running. The three-track recording machines which several studios have installed have now, by coincidence, become natural instruments for stereophonic recordings, which are being intensely studied. Wide use of stereophonic recordings for largescreen and stereoscopic shows is in prospect. Now that the design and application of magnetic recorders has reached mature stage, more thought is being directed toward study of the nature of the magnetic process itself, particularly with a view toward standardization. The necessity for standardization arises, of course, from the fact that all products should reproduce on standard equipment, or at least deviations from standard should be under control. It is generally agreed that recordings should be laid down in such a way that they may at any future time reproduce interchangeably with future products regardless of improvements in magnetic materials and techniques. Therefore, a "standard reproducer" should be defined and me^ns provided for its calibration. This is not a simple task in the case of magnetic recording because the characteristic is controlled by the respective recording and reproducing gaps as well as the magnetic material of the track itself, and measurement of these elements is difficult and, in general, requires dynamic measurements. Many groups have been working at the problem of film calibration during the year. These include equipment manufacturers, the JCIC, the SMPTE Committee on Sound and the CCIR (International Radio Consultative Committee). Through the latter, the "long George R. Groves: Progress Committee Report 539