Motion Picture Herald (Mar-Apr 1945)

can "guess" accurately the proper places for these speakers. The opening in the wiring wall for the speaker should be at least 1 inch larger all around than the actual size of the speaker. In case the proper splay of the speaker is not accurately determined, this opening should be made about 4 inches larger all around than the size of the speaker to allow for any possible shifting in arriving at a final location. The size of a speaker unit having high-frequency and low-frequency units combined, runs about 41 inches high by 28 inches wide and 18 inches deep. The shelf for the speaker should be of sturdy iron construction and rigidly fastened to the wing wall. It should be about 4 inches larger all around than the base of the speaker to allow for any shifting that may be necessary in the final setup of the speaker. The height from the auditorium floor to the bottom of the speaker should be determined only after a careful survey is made of the auditorium, both physically and acoustically. The front of the speaker opening can be covered by a light scrim material stretched on a wood moulding all around the opening. Heavy damask or fabric should never be used for covering this opening. After the scrim ' fabric is installed, it should be vacummed cleaned carefully at least once a month for removal of accumulated dirt and dust, which cakes rapidly over the mesh of the material. This scrim material can be purchased in colors to match the interior decorrations. The wiring connection of the public address speakers when of the high-frequency and low-frequency unit type should be effec THE LAMPS YOU'LL EVENTUALLY BUY sill 'There's a Branch Near You' I PROJECTION ARC LAMPS Deliver the snow-white light essential to satisfactory projection of Technicolor pictures— double the light of the low intensity, at only slight increase in operating cost. If you can qualify, we will help you apply for new equipment now. AT I ON A L THEATRES U P PLY Division of Notional . Simple, . Bludwo.lh, In ted by running two No. 18 braided-rubber covered wires in a ^4-inch conduit and splices made to the units from the outlet box at each speaker location. As in anything else, a first-class, permanent public address system can only be expected when the equipment used is of the best, and the workmanship of the highest order. Air-Conditioning Can Pay Its Own Way (Continued from page 18) compressor combined) is likely to he vibration-free, but a good mounting is worthwhile nevertheless. Fans must have flexible bearings or vibration mountings. Canvas connections are a necessity between fans and duct work. Big (not over-size) fans are desirable from the noise viewpoint. Small ducts with high air velocity are okay with proper take-off connections and proper outlet grills. But if this is done, it takes a good engineer to do it right. EXTRAS OF DECORATION Decorating and redecorating are often items of high expense caused by improper planning of the air-conditioning equipment and its space. If, because of noise, sound absorbing panels are needed, these can really be a decorative problem, and one expensive to solve. If, because of drafts, trick baffles or deflectors are needed, these can mess up sound as well as be a decorator's nightmare, all at the exhibitor's expense. Special construction can materially add to costs. Sound travels over framing members. This in turn calls for trick construction to isolate noise sources. Heavy equipment requires extra heavy foundations. In some cases these require heavier building structure provisions. And so it goes. Just in considering these points alone for the theatre man previously referred to, pointed out how he could save from 30% to 50% of his air-conditioning estimate of cost, depending on the way it was done. I'm not in the business of doing such work. I made the study because I was curious to see where the costs were and how savings could be made. I commend the same effort to all exhibitors, and to their architects and engineers. [Mr. Boester, an air-conditioning engineer with broad experience in the air-conditioning of theatres and comparable types of buildings, is director of housing research at Purdue University.] As field representatives of Marsh Wall Products, Inc., manufacturers of Marlite plastic and wood veneers, met with home office executives at the Dover, Ohio, plant. "In Marlite," the field men were told by V. R. Marsh, general manager, "we're marketing a product with a future greater even than its past." Bite Sfflmi hull 34 BETTER THEATRES, APRIL 28, 1945