Motion Picture Herald (May-Jun 1946)

A CATALOG OF THEATRE EQUIPMENT, FURNISHINGS, OPERATING SUPPLIES AND ARCHITECTURAL MATERIALS, ALPHABETICALLY LISTING DEALERS BY STATES, AND MANUFACTURERS ACCORDING TO CLASSES OF PRODUCT Classes of Product and Their Manufacturers ACOUSTICAL PRODUCTS AND ENGINEERING THE ENTIRE sound transmission system of the theatre is to be regarded as including the auditorium itself, the acoustical character of which bears directly and fundamentally upon the naturalness as well as audibility of the speaker output. Acoustic characteristics can be controlled by the architectural design of the auditorium; the designer, however, is often limited by other considerations (even in a new building, notably by site, capacity and desired style), necessitating general or partial recourse to acousticcorrection materials. Such materials may be divided into two general groups : Materials which are concealed, and those which have decorative qualities of their own. Acoustic treatment properly takes note of the entire range of available sound frequencies, hence the use of more than one type of material is sometimes advisable, since some are more efficient as absorbents of low frequencies than of the high frequencies, while others have contrary characteristics. These materials are available in various forms and substances. Those most frequently used in motion picture theatre auditoriums are vegetable fiber and mineral tiles, rock wool and felt blanket, pressed wood veneers, and acoustic plaster (which latter may be tinted in mixing so as to eliminate painting). Ornamental fabrics are commonly applied over those materials which (like rock wool) are not decorative, but perforated tiles may also be used. Before painting any materials, the manufacturer, or competent acoustics engineers, should be consulted so as to make certain that the absorption efficiency be not too greatly reduced. The decorative acoustic materials are also well adapted to the finishing of foyer and lounge areas that are immediately off the auditorium, where noise reduction may be importantly indicated. Altec Service Corp., 2S0 W. S7th St., New York City (acoustic counsel only). Armstroner Cork Co., Lancaster, Pa. Barclay Manufacturing Company, Inc., 385 Gerard Avenue, Bronx, N. Y. The^Celotex Company, 120 S. LaSalle Street, Chicago. The Insulite Company, 1100 Builders Exchange, Minneapolis, Minn. Johns-Manville Corporation, 22 East 40th Street, New York City. Keasbey and Mattison Company, Ambler, Pa. Kimberly-Clark Corporation, Insulation Division, Neenah. Wis. National Gypsum Company, 325 Delaware Avenue, Buffalo, N. Y. United States Gypsum Company, 300 W. Adams Street, Chicago, III Wood Conversion Co., First National Bank Bldg., St. Paul 1, Minn. ADVERTISING — See Exploitation Mechanisms and Letters and Frames for Attraction Advertising. • AIR-CONDITIONING AND VENTILATING EQUIPMENT AIR-CONDITIONING facilities consist in means of controlling automatically the temperature and relative humidity of the air, and of distributing the air so that it reaches all breathing zones at a temperature, percentage of relative humidity, and rate of motion representing comfortable and healthful atmospheric conditions for normal people. Dust, pollen and other particles suspended in the fresh air should also be filtered out before it is introduced into the distribution system. All-year air-conditioning of course signifies equipment providing mechanical control of temperature and relative humidity of the distributed air no matter what the condition of the air may be outdoors. SUMMER AIR-CONDITIONING For summer air-conditioning, some measure of mechanical refrigeration is usually indicated; however, in areas of low relative humidity, a cooling-tower evaporative system may be employed, while well water (rarely water from city mains) may be used as the cooling agent for coils over which the air is passed, if a sufficient quantity of water at a low enough temperature (maximum 55') is available. A method designed to reduce the mechanical refrigeration capacity that would otherwise be necessary, is that of storage refrigeration, by which a relatively small compressor is operated a large part of the day to "build up" the aircooling agent to a quantity sufficient for the load during performance hours. The self-contairted units of the general type used in stores and similar spaces (filters, mechanical refrigeration plant and fan equipment housed in a cabinet) are adapted to the summer air-conditioning of small auditoriums and several units of suitable capacity can be combined to serve medium-sized auditoriums, though it is commonly found that the distribution requirements of the latter advise other methods. AIR DISTRIBUTION Distribution systems for the air-conditioning of theatres practically always consist in ducts with fans of proper capacity, and outlets, or grilles, providing control of air motion. Fans — those of the multi-blade ("squirrelcage") type are usually preferable — must be of a capacity and design to move the required amount of air against the resistance of the duct system, with the least expenditure of electric current, and without transmission of noise to the auditorium and other rooms. Air outlets should be of a design to assure thorough mixing of cooled air with room air before it is allowed to descend to the breathing zone. AIR CLEANSING Filtering equipment, which is installed as part of an air-conditioning system but which usually needs to be replaced from time to time, is of various types. Some filters use spun-glass fibers, some steel wool, others paper, hogs' hair, wood shavings, etc. The filtering material is held in a frame which is inserted into the duct or intake. Filters of this type are thrown away and replaced with a new one as the accumulation of dirt requires. Also available, however, is a self-cleaning type of air-filtering jdevice, but it is seldom adapted in price to theatre installation. (See also Air Purification: Electric & Chemical. ) CONTROL EQUIPMENT Efficient operation of an air-conditioning plant requires dependable automatic control specifically adapted to the operating characteristics of the plant. Control equipment available ranges from a simple cut-in for a single compressor to a motor-operated monitoring cabinet inter-relating all operating elements of the system, including the heating plant. Two accessory instruments of value in theatre operation should be cited here. One is the recording thermometer, which provides continuous temperature readings automatically transcribed BEHER THEATRES. MAY 4, 1946 33