Motion Picture Herald (Jul-Aug 1936)

MODERN PROJECTION PROJECTION . SOUND REPRODUCTION . ACOUSTICS Actual Theatre Reproduction With the Two-Way Horn System • Describing the special arrangements at the Astor Theatre in New York, installed for the presentation of nThe Great Ziegfeld" and employing the so-called Shearer method recently developed installed originally for improved reproduction desired for the MGM production, "The Great Ziegfeld," a special sound system incorporating, for the first time under such commercial conditions, the so-called Shearer two-way horn system, has been brought to perfection at the Astor theatre in New York City. Possessing a number of new characteristics, it most directly represents the researches of Shearer himself, and of Mr. Lester Isaac, director of projection for Loew's, Inc. Seated down front, in an end seat, at about a 45° angle to the screen, the writer, attending a performance with Mr. Isaac, found the sound of an unusually high quality. From straight in front of the screen it is as nearly perfect as one could hope sound to be. Not only is the system itself worthy of detailed examination, but the story behind it is interesting. In telling it, after the performance, Mr. Isaac really described the workings of the system. His account, more or less accurately quoted, was as follows : "Some two years ago a horn system known as the 'Fletcher System' was demonstrated, the same being the property of the Bell Telephone Laboratories. Several demonstrations were given by means of direct monitoring, whereby the performance of Stokowski's Symphony Orchestra, then playing in the city of Philadelphia, was transmitted to New York City and reproduced through the 'Fletcher horn system.' The reproduction was so excellent that the attention of various technicians was drawn to it. "I immediately took the matter up with a certain sound equipment company, requesting it to duplicate the Fletcher horn system for theatre use. I was promptly assured that it was impossible, due to physical and engineering design of the horn system then in use. "Being of the well known never-say-die type, and willing to take reasonable chances on anything that gave promise of improvement in projection results and therefore the production of better shows, I discussed the matter in detail with Douglas Shearer, director of recording for MGM at Culver City. "During the discussion, Mr. Shearer conveyed the idea that he was not satisfied with reproducing systems then in use, in which view I was in complete accord. I informed him, however, that due to lack of facilities it would be physically impossible for my department to experiment in the construction of the horns, units, etc., necessary to development of a proper sound reproduction system, whereupon Mr. Shearer agreed to attempt the development of a suitable horn for theatre use along the lines of those designed by Dr. Harvey Fletcher. "After five or six months of study and laboratory experiments, Mr. Shearer requested my presence at the MGM studios, in response to which myself and Mr. F. W. Boettecher, chief engineer of sound in my department, made a flying trip to Culver City, where we found a large sound stage used by Metro for their music recording, which was acoustically suitable for the tests about to be made, and equipped with all known horn systems from the major sound equipment manufacturing companies, together with the new Shearer two-way system. "After very careful tests of them all, the horn of one or another company was eliminated, the conclusion, after much careful work, finally boiling down to two systems, namely the three-way wide range system and the Shearer two-way system. Still further comparative tests proved beyond any possible shadow of doubt that the Shearer two-way system gave best results. In attempting to describe this system in non-technical terms I may best accomplish the purpose by comparing it with the systems now in use. "Present day systems, as you know, consist of a multiplicity of horns carrying midrange (which includes the greater part of the dialogue range), plus one or more high frequency horns, or 'tweeters,' plus one or more low frequency horns, or 'woofers.' This makes up the horn system for the present three-way wide range. Although upon its introduction it was thought to be the last word, the fact remains that it is considerably lacking in perfect projection of sound. ELIMINATING 'DEAD SPOTS" "In large theatres, as well as in some smaller ones, the multiplicity of horns has proved to be unsatisfactory, due to the fact that such horns are too directional — their beam too narrow — so that it is necessary that they be flared at different angles to secure proper distribution in auditoriums of different dimensions. "Under this condition it follows that between the end of the beam of one horn and the other, there is a so-called dead spot, and in theatres where extremely wide angles are involved, requiring anywhere from three to six horns, in walking across the front portion there would be a sort of 'picket fence' effect between live and dead spots. The dead spots in many cases contain a goodly number of seats, from which the sound, as heard by persons occupying them, lacks illusion and presence. "The system I am describing completely eliminates this condition, because of the fact that its mid and high-range horn is of the cellular type, so designed that a horn of any given angle may be supplied. For example, if the angle of sound projection be 45° on each side of the screen center line, then a 90° horn would be installed, thus insuring even distribution over July 25, 1936