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1947-48 Theatre Catalog, 6th Edition, Page 263 (249)

1947-48 Theatre Catalog, 6th Edition
1947-48 Theatre Catalog
1947-48 Theatre Catalog, 6th Edition, Page 263
Page 263

1947-48 Theatre Catalog, 6th Edition, Page 263

Hints on Achieving Good Acoustic


A Review of Sound and Acoustic Principles;

Properties, Uses, Maintenance of Materials

Despite the facts that titalking pictures" are now twenty years old and that most of the theatre-going public has practically forgotten the ttsilent screenf the problem of providing an acoustically good house for exhibiting modern motion pictures is a constantly recurring one. In view of the fact that the science of architectural acoustics was well advanced long before the talkies were even considered as a practical possibility, it appears-although a bit uncomplimentary e-that exhibitors generally have neglected to become informed on one of the most important factors in giving their patrons satisfactory presentations, namely, good hearing conditions.

There is no mystery in providing good theatre acoustics. This applies whether the thought begins in the blueprint stage, whether the house is now in operation, or whether an old store building is being remodeled to become a theatre. Most theatre acoustical problems arise from oversight, lack of recognition, or an attempt to short-cut a reliable acoustical correction job. There is trouble ahead in either case.

The best equipment will not overcome an unfavorable acoustical condition, nor will perfect acoustics mold a high-fidelity

ACOUSTICAL TREATMENT in the auditorium ot the Riviera Theatre. Saint Paul, Minnesota. is applied on approximately two-thirds of the side walls. The rear wall, however, is fully treated. The material throughout is Acousti-Celotex. The mechanically made openings permit the sound waves



.lcouxtiral Department. The Celolnx Corporalinn

presentation out of sound generated by faulty equipment. Irrespective of the equipment used, unless the customers can hear what comes out of the speakers with some semblance of its original quality and clarity, the presentation is bound to be unsatisfactory. And, what happens to sound after it leaves the speakers is wholly dependent upon the acoustical conditions in the house.


While in seine instances shape and design of a theatre have a bearing on the resulting acoustical condition, in all instances the major factor is reverberation. An overly reverberant house will scramble words and music, and will be noisy. A house with too little reverberation will be dead. Between the two evils, perhaps the dead house is to be preferred in that extra power can be applied to carry words and music to the listeners. While the quality will, of course, be poor, the sound will be distinct. No amount of power can overcome excessive reverberation. I Additional

power will only aggravate the condition and increase the noisiness of the presentation.

In the average house, the solution lies simply in providing a proper reverberation time for the size of the house. Distribution of sound must, of course, be considered, but in the main this presents no serious problem. Modern, highly directional sound equipment will put the sound where you want it, providing it has a chance to get there, as you want it.

Reverberation is the term used to denote the tendency of a room to keep a sound alive and audible after the original sound source is cut off. Reverberaation time means the time in seconds that sound is prolonged from the instant of cut-off. For acoustical purposes, this is a definite measure of the time it takes for a sound to drop to one-millionth of its original intensity. All architectural acoustical data is based on this measure.


Sound is energy. Every sound wave that leaves the speakers has a definite amount of acoustic power in it. Until enough of that power is used up, or dissipated, to lower the energy below the threshold of hearing, it is an audible

to reach the absorbing back and are of such size that painting with ordinary mixtures and methods does not close them up. When AcoustiCelotex is finished with an oil-base paint or other washable tinish, it can be cleaned by any method the manufacturer says is suitable to the finish.
1947-48 Theatre Catalog, 6th Edition, Page 263