Exhibitors Herald and Moving Picture World (Apr-Jun 1930)

April 12, 1930 Exhibitors Herald-World 5E SOUND IN THE THEATRE NEW CONSIDERATIONS IN THE TREATMENT OF ACOUSTIC PROBLEMS By S. K. WOLF In which an eminent acoustics engineer confesses to have little respect for those who would only apply old formulas in seeking new truths in acoustics WHAT is correct acoustic condition? Much has been written on this subject, and that this condition is necessary in theatres is a fact now generally accepted by all wideawake exhibitors. The public, too, is becoming “sound conscious” and demanding certain standards of acoustic condition in the theatres it will attend. Although much has been said about correct acoustic condition, little has been done to define it. Most of the effort in acoustics has been directed towards the removal of serious acoustic defects, rather than the attainment of best acoustic condition. Few theatres not specifically designed by competent authorities for the reproduction of talking pictures will satisfy all the requirements of correct acoustic condition. Of two thousand theatres analyzed by Electrical Research Products, Inc., less than ten per cent may be said to have been correct acoustically prior to the application of remedial measures in accordance with our recommendations. However, about 28 per cent have been free from serious difficulties. The improvements in recording, and the sound consciousness of the public will demand that the theatres which are to succeed be brought to a standard of acoustic condition better than just “acceptable.” The sound conditions in a theatre must be made the best possible — not merely good enough to avoid complaints from patrons. The latter standard of acoustic quality is far too prevalent today. No one expects to attract audiences in the face of competition, with theatres that are unsightly or in need of decoration — nor would they hesitate to make the investment required for such decoration. Surely, with an undertaking, the appeal of which is largely in sound, the wisdom of an investment to insure proper sound conditions must be obvious. The cost of extensive acoustic treatment is generally comparable with the cost of decoration. The work of Prof. W. C. Sabine included the statement of a formula for computing the so-called “time of reverbration,” or the time required for a sound of specified loudness to die out in a room. This formula, while constituting a basic contribution to acoustic science, has been in many cases taken to be not only the beginning but the end of the science. Pages have been written showing the simplicity of determining the number of socalled “absorption units” present in a theatre and how many must be added to reach a time of reverberation, called “optimum.” These units of absorption are then furnished by placing in the theatre a certain number of square feet of some material which will absorb sound, the results of this treatment purporting to give correct acoustic condition. The results obtained by this method have, undoubtedly, corrected serious defects in many theatres and have improved acoustic conditions in many more. The new industry created by talking motion pictures is surely not content, however, to stand still. Compare for a moment the silent motion pictures of a few years ago and the theatres in which they were shown — the “flicker melodramas” in the nickelodeons of the motion picture industry’s early days — with the feature pictures and the theatres of today. The great advances in the quality of pictures and the theatres now, must surely be matched by the improvements which are being made in the talking pictures. At first, the talking picture was a novelty and people flocked to hear sound of any kind or quality for its novelty. Many theatres were acoustically so poor that speech could only be understood with difficulty — and yet the people came to hear. Already those days have passed, and acoustic measures have been taken in thousands of theatres to insure that speech is at least intelligible. The methods of applying Sabine’s formula, which have been fre quently outlined in considerable detail, were fully adequate to accomplish these results. We are now entering upon the next era of sound reproduction; that is, not merely the correction of serious acoustic defects, not merely to make speech so it can be understood, but to produce acoustic conditions in a theatre such that the naturalness of sound will cause the audience to completely forget the mechanical apparatus and, through the sound conveyed to their ears, to live in their minds the scenes enacted on the screen. The first recordings of sound were accepted if the sound was synchronized with the action and the speech was intelligible. This again satisfied the desire for sound as a novelty; but today recordings are being made to reflect the naturalness of sound, and the illusion of motion of sound as the figure in the picture moves. The recordings of tomorrow will contain still further subtle improvements that will permit the talking picture to become an art by itself, distinct from that of the motion picture and that of the stage. The benefit of these improvements will, however, be received only by those houses which have a truly correct acoustic condition. The mere elimination of serious troubles will not suffice. The first step in analyzing an acoustic problem by Electrical Research Products, is the gathering of accurate data concerning the theatre. For this purpose, a corps of men are employed, all of whom are technically trained and who have had experience in the installation and servicing of the apparatus. Additional specialized training totaling several weeks in the company’s own schools under the instruction of experts in each phase of sound reproduction, further qualifies them for the preparation of acoustic surveys. These surveys make a searching inquiry into all of the architectural features of the theatre which may have a bearing in any way upon its acoustic qualities. Many mistakes in