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1947-48 Theatre Catalog, 6th Edition, Page 258 (244)

1947-48 Theatre Catalog, 6th Edition
1947-48 Theatre Catalog
1947-48 Theatre Catalog, 6th Edition, Page 258
Page 258

1947-48 Theatre Catalog, 6th Edition, Page 258

Acoustics and the Audibility of the Show

Assurance of Perfect Hearing Also Includes

The Elimination of All Distracting Noises

The audience and the showman find it to their mutual advantage and satisfaction for the audience to hear only what itwants to hear, or the showman wants it to hear, and that, clearly. This article* will concern itself with those parts of the theatre building which have a direct bearing on the audibility of the show.


The audience wants to hear the actor, the singer, the orchestra, the instrumental soloist, the organ, the audible components of the sound motion picture, and any other sound which is part of the show. It does not want to hear the elevated, auto horns, fire sirens, wind or rain outside the theatre while the show is in progress, or scraping feet

t t'The Audience Hears," originally appearing in the October, 1947, issue of Progressive Architecture, whose assistant editor, Charlotte Masters, has granted special permission to reprint the text and to reproduce from the original art work the illustrations. The article is one of the chapters in a forthcoming book by the present authors on theatre planning, the first such work to derive plan from an analysis of function.

ISOPHONIC CEILING, designed by Proi. H. L. Cooke, 01 Princeton Univercity. installed in the Princeton Playhouse (Thomas Stapleton, architect). The flutinqs ensure that reflected sound will cover the entire audience; added to direct sound from the stage. this produces the same total value at every


Respeclirely, Slevens Inslitule 0/ Technology and Yale Universin

in the aisles and rows, rattling foot rests, squeaking seats, banging lobby doors, or whistling fans, roaring blowers, knocking radiators, or telephone bells, buzzers, snap switches, the noisy shifting of scenery, or any unplanned distortion of any sound which is a part of the show.

It is up to the architect to insure perfect audibility of the show, and by the same token to protect the audience against distracting sounds such as those listed above. He must (1) eliminate from the audience area all unwanted sound (noise, that which is not part of the show); and (2) assure audibility for all sound which is part of the show.


Unwanted sound is noise. Noise in the theatre masks portions of the show

and limits subtlety. It is therefore desirable to keep the theatre as free as possible from outside noise, and noise originating inside the theatre.

The average noise level in existing metropolitan theatres with audience present is about 50 dbl. In the same locations 40 db. is an entirely feasible level involving little, if any, additional construction expense. The best theatres often have a level of about 30 db. The level of ordinary conversation (at 3 feet in open air) is about 65 db.

Sound Transmission

Noise is either airborne or solid-borne. Steel structural members transmit sound with considerable emciency. Sound thus transmitted becomes airborne when wall, floor, or ceiling areas or fixtures are vibrated by the structural members and act much as the sounding board of a musical instrument.

Idb. means decibel, the handy unit of sound intensity; the log of the ratio of the sound power to a. standard reference: 10416 watts per square centimeter.

seat. When ceilings are laid out, they must be planned to reflect the sound back to the audience in such a manner that it will be neither concentrated in certain spots or out of phase with the direct wave. (Photograph courtesy Princeton Alumni Weekly, Margot Cutler, and Princeton University Press.)

1947-48 Theatre Catalog, 6th Edition, Page 258