The Exhibitor (Nov 1938-May 1939)

BM-6 BETTER MANAGEMENT MARTIN D. HARRIS V ice President, Capitol Theatre, Inc. Operators of the State Theatre Hartford, Conn. Saves $ 3,000 When Hurricane, Flood Ravage Theatre HARTFORD, CONN.— "When the hurricane and flood, that put many New England theatres 'in the dark,’ struck our big State Theatre here, we immediately called our Altec inspector, Charles E. Maass,” said Martin D. Harris, vice president of Capitol Theatre, Inc. "When he first arrived, the auditorium was full of water, and he had to ride across the stage on a raft to inspect the horns. "I fully realized for the first time the importance of the testing and other equipment the Altec man uses. By means of it, Maass saved us from having to make almost a complete rewiring job, and enabled us to open our theatre, one of the largest in New England, without any serious electrical troubles. "Our Altec service contract has saved us approximately three thousand dollars, or the cost of service for many years to come.” Theatres in flood stricken New England with comprehensive Altec agreements received thousands of dollars worth of emergency replacement parts without additional cost. Let the Altec man in your neighborhood explain the value of an Altec agreement to your theatre. .ALTEC ALTEC SERVICE CORPORATION 250 West 57th Street New York City. Gentlemen: Have the Altec man call me for an appointment. I want to hear the Altec story. NAME THEATRE ADDRESS CITY 82 . . THAT YOUR THEATRE MAY NEVER BE DARK." Loud Speakers and Dividing Networks AS MEASURED with a flat over-all electrical characteristic, the trend of the acoustic response of the loud speaker system when measured by the conventional warble frequency method shall not vary more than plus or minus three decibels from the following characteristic: flat over the frequency range from 5 0 to 2,000 cycles; not decreasing more than 5 decibels to the octave in the range from 2,000 to 10,000 cycles, and not decreasing more than 10 decibels from 5 0 to 3 0 cycles. THE LOUD SPEAKER SYSTEM shall be designed to carry adequately the rated output of the amplifier system. The conventional method of measuring referred to above involves the averaging of five or more readings made with the microphone close to the speakers. In making these measurements, care must be taken to select microphone positions which will not favor the response of either the high or low-frequency units. The most suitable conditions under which such measurements can be made are either in a large acoustically dead room or out of doors. In either case the intensity of extraneous noises must be sufficiently low not to affect the measurements. A MAGNETIC STRUCTURE shall be provided which is efficient and distortionless as present deluxe two-way horn systems, to avoid the necessity of increasing the power-handling capacity of the amplifiers. In certain installations it is necessary to have a wide horizontal coverage, and a high-frequency horn shall be available which will cover a maximum horizontal angle of 105 degrees. Horns shall also be available to cover a vertical angle of 6 5 degrees. Past practice indicated the extreme need for reducing rear radiation from loud speakers, and it is desirable that loud speakers be manufactured which have a minimum of rear radiation. The dividing net work shall be designed to have an attenuation of approximately 12 decibels to the octave. Servicing Requirements Accessible terminals for a volume dictator and a switch for the substitution of a resistance equivalent to the loud speaker load should be provided at the output of the power amplifier in order that the electrical characteristic may be conveniently measured. It is further recommended that a meter or its equivalent be made available on the various vacuum tubes, as it is difficult to service equipment which does not have adequate metering facilities. The design of the sound head should be such that items subject to wear are easily removable; for instance, provisions should be made for the easy replacement of the felt pads in the pad roller. All equipment and wiring should be available for inspection and maintenance. For instance, an accessible method for checking the photoelectric cell transformer and wiring without disturbing the rotary stabilizer, if used, should be provided. Any part of the equipment which is subject to measurement should be designed so that such measurement may be conveniently made. From a servicing standpoint, it is desirable to mount as much of the projection equipment as practicable in the booth, such as the field supply and dividing networks for loud speaker systems. Test Reels THE RESEARCH COUNCIL of the AMPAS have announced another forward step: to help a better show to the public, "balancing reels,” recorded in Hollywood studios especially for this purpose, are now available for all theatres desiring them. These films make it possible for the projectionists to balance machines so that one will not reproduce louder or softer than the others, and present an entire show without unwarranted changes in the loudness or softness of the dialogue or music. FOR FURTHER EFFECTIVE CHECKING of theatre sound equipment, the Research Council recently made available primary and secondary multi-frequency test reels. The primary standard contains frequencies from 40 to 10,000 cycles, with a 1,000 cycle frequency on each end. The secondary standard contains frequencies from 40 to 8,000 cycles, with an added 1,000-cycle clip on the proximal end. Both reels are available in variable density and the variable area prints. Credits For valued service in the preparation of this article — for pictures, literature, ideas, and suggestions — thanks are expressed to K. M. Macllvain, Society of Motion Picture Engineers; the Society itself; L. W. Conrow, Elmer O. Wilschke, Warren Connor, R. J. Kautsky, Altec Service Corporation; Research Council, Academy of Motion Picture Arts and Sciences; Walker Soundscreen; International Projector Corporation; Dictograph Products Company, Inc.; C. N. Reifsteck, RCA Manufacturing Company, Inc.; Electrical Research Products, Inc.; The Ballentyne Company; National Theatre Supply Company; The Strong Electric Corporation; Brenkert Light Projection Company; Motiograph, Inc.; Hurley Screen Company; Imperial Electric Company. December 14, 19} S