International projectionist (Oct 1931-Sept 1933)

28 INTERNATIONAL PROJECTIONIST October 1932 New RCA 'High Fidelity' Double-Edged Sound-on-Film Track A — In the earlier type, of variable area sound track, the single-edged black silhouette of the sound wave was employed to vary the width of the light beam which was directed upon the lightsensitive cell. The entire remaining portion of the sound track not occupied by this black silhouette permitted light to pass. However, the natural grain of the film, plus small dirt particles which adhered to its surface, served to cause a host of infinitesimal shadows in this light beam, which resulted in a rushing and crackling sound called "ground noise". In this case where the black silhouette was the smallest in area, the sound volume was lowest, and the "ground noise" produced by the relatively large clear area was then at its greatest volume — and, of course, more noticeable to the listener. 8 — In the modern "High Fidelity" sound track, a symmetrical or double-edged image of the sound wave is employed — and it is reversed, clear for black, compared with the earlier type of sound track shown at "A". The entire background of the sound track not actually occupied by the clear image of the sound wave is now black. Therefore, when the sound is at minimum volume, the clear portion of the track is narrowest, and the black background which occupies the entire remainder of the sound track completely shuts off the remainder of the light beam. Thus, the' film grain and even the dust particles in this black area have no effect whatever upon the resultant reproduction, and the so-called "grounl noise" is now absent in "High Fidelity" system, s stem. man should further the idea that extended frequency range is something to be played around with, something to be regarded as a mere attachment to or improvement upon existing reproducing apparatus. Extended frequency range recording seems to this writer to require ideal reproducing conditions if its full value is to be realized. Every element in the system must be right. There must be no halfway measures about it. Fitting extended frequency range to existing apparatus is all very well as a catchline, but that it will work out well in practice is seriously to be doubted. Diamonds are not set in lead settings; extended range recordings should not be reproduced by means of limited range equipment. Strict honesty and absolutely onthe-level dealing should characterize the promotion of this equipment. The High Fidelity system of RCA Photophone is credited with the ability to encompass the full range of from 40 to 10,000 cycles. Differently expressed, this range is so close to that which is considered to include "everything" as to render silly any hair-splitting discussion of lower or higher levels. It is generally agreed that a majority of existing reproducing equipments cut-off sharply at 4,000 cycles — although it seems to this writer that many equipments cut-off noticeably this side of that figure. The question naturally arises: "What will happen when a recording closely approaching 10,000 cycles is run through a majority of reproducing equipments now used in theatres?" The answer is: "Nothing". An amplifier that cuts-off sharply in the neighborhood of 4,000 cycles will cut-off an extended frequency range recording precisely at that point. The only advantage of 10.000-cycle recording in this instance would be a further re duction in ground noise. Changes in existing reproducers are necessary, positively so, otherwise we shall have no material benefits from this new development. RCA Photophone asserts that any of its equipments dating not farther back than two years will reproduce satisfactorily up to 8,000 cycles. Those equipments antedating that period will have to be altered. In all cases, installations of RCA's High Fidelity system will require a new sound sprocket and a different baffle for the speaker. Inclusion of the very high frequencies means that sprocket wear to even a slight degree can no longer be tolerated, as the slightest wear will manifest itself in a pronounced flutter in the reproduction. As with every refinement of the art, extended frequency range systems require additional watchfulness and care by the projectionist. An explanatory note on the new RCA sound track i? appended hereto, together with drawings of both new and old tracks. Erpi's Wide Range System Wide Range, the erpi extended frequency range development, possesses the same general advantages previously cited herein. This writer was privileged t" hear this new erpi development at a private demonstration at which a clever method of changeover from old to new reproduction enabled the hearer to make an accurate comparison of relative merits. Needless to state, the new Wide Range so far outstripped the old method as to occasion wonderment that the latter ever was tolerated. It's a beautiful piece of work in every respect, and a first hearing of a special organ recording by Wide Range is as thrilling an experience as one could desire. Specific details as to requisite changes in existing erpi equipments in order to fit them for faithful reproduction of Wide Range recordings are not available at this writing. The writer is aware that the new erpi systems employs a filter system which splits the frequency range into "highs" and "lows", 3,000 cycles being the dividing point, with the outputs being fed into a combination of two horn units. Whether the general public will be properly appreciative of this new development is not the concern of this article. Radio manufacturers, prodded to improve the frequency response characteristics of their sets, replied with smug assurance that the public was so educated to poor sound reproduction that it not only would not appreciate high quality reproduction but actually would resist it. Maybe this represents an accurate reflection of public taste (which I doubt) ; but if it should be so, then all efforts to improve the sound reproduction art should cease at once. On this theory, the motion picture business and all other businesses might just as well call it a day insofar as refinement and progress are concerned. This new extended frequency range recording and reproduction is great stuff. It's grand. It's magnificent. NEW SIMPSON CO. TO HANDLE BRINNER LENS BUSINESS THE Simpson Instrument & Lens Corporation, 1737 North Campbell Avenue, Chicago — a newly formed corporation of which Ray Simpson is president — has purchased the lens business of the Brinner Optical Manufacturing Company. The new company will specialize in the manufacture of scientific lenses, as well as special lens development work for manufacturers and lens repair service. Mr. Simpson was formerly president of the Jewell Electrical Instrument Company.