Motion Picture Herald (Nov-Dec 1944)

Whether It's OUTSIDE INSIDE Wagner Translucent Plastic Changeable Letters serve equally well, compelling greater attention and attracting more business. Hundreds of theatres are discarding their old style, solid, opaque letters for these attention magnets. Affording sharply silhouetted copy by day and the colorful brilliance of neon by night, Wagner letters permit fullest utilization of the light which shines through them. They are available, without priorities, in four beautiful, non-fading colors which go all the way through the letters. There is no surface color to chip or scale off. Painting is never required. Obtainable in 4" and 10" sizes, and in fonts of assorted colors (red, green, blue, amber and opaque black) from 76 letters up. Wagner Lobby Display units are quality constructed of pre-war materials. Made of sheet steel, with attractive white enamel finish, they are easy to install in any desired length. Letters are mounted on the bars in the middle or firmly held in position at the top or bottom by slipping under the clips. NOW AVAILABLE Aluminum letters for replacement and for those who believe that greater durability is more important than advertising value. See your theatre supply dealer or sign man, or write for literature and name of nearest dealer. 218 S. Hoyne Avenue CHICAGO 12, ILL. SUPER-LITE LENSES PRO-JEX SOUND UNITS It pays to install the bestir patrons appreciate A TRY-OUT WILL CONVINCE YOU Projection Optics !;?: 330 LYELL AVE., ROCHESTER. N.Y. U.S.A. Acoustic Tools for The Sound Engineer Reviewing ELEMENTS OF ACOUSTICAL ENGINEER. ING, by Harry F. Olson, E.E., Ph.D.; New York: D. Van Nostrand Company, Inc. Price $6.00. THE SUBJECT of acoustics, like its first cousin aerodynamics, has appeared so recently on the horizon of applied science that most investigators have done little more than glimpse its bare outline. But recently a few hardy explorers have approached it closely and of these none is more articulate or better qualified to vv^rite a documented reference text on the subject than Dr. Harry F. Olson, Acoustic Research Director of RCA Manufacturing Company. His "Elements Of Acoustical Engineering" first appeared in 1940. That it now emerges in its third wartime printing is a tribute not only to Dr. Olson, but to the utility of this newest of applied 'sciences. Because pioneers in acoustics for many years confined their investigations of sound to its behavior in enclosures such as public auditoriums, laymen came to accept the term "acoustics" in its narrow sense of "architectural acoustics." Dr. Olson's book adopts the original meaning and broadly encompasses the whole realm of sound and vibration. Beginning with the analysis of sound originating at a point source. Dr. Olson traces the phenomenon as wave motion through various elastic media to its final perception by the sense of hearing. Moreover, his discourse takes into account almost every practical instrumentality so far devised for the production, reproduction and measurement of sound. Perhaps the most singular feature of Dr. Olson's treatment of his subject is his facile use of analogies. In charting a course from an acoustical problem to its solution. Dr. Olson does not ask the engineer to employ new methods. Instead, he deftly singles out the elements common to acoustics and of mechanics and electrical circuits. He then demonstrates how any acoustical problem may be solved by the familiar techniques of the two established sciences. Automobile mufHers, for example, become electrical wave filters and a radio-equipped living room, in Dr. Olson's eyes, looks precisely like the spring suspension system of a Mack truck! If you can design a filter-circuit to end the 60-cycle hum in a theatre sound system, then' with Dr. Olson's book you're fully equipped to deal with wardroom vibration on a battleship. After the most searching exploration of sound waves, acoustical radiating systems and acoustical elements generally, Dr. Olson investigates all of the better known instruments of acoustics: microphones, loudspeakers, corrective networks, measuring apparatus, architectural acoustics and finally speech, music and hearing. In the realm of sound systems he includes the telephone, binaural and auditory perspective reproduction, sound motion pictures, radio and the phonograph. The text covers 328 pages, is fully illustrated, and contains literally hundreds of valuable references to former articles and books by the author and his contemporaries, it 8 BEHER THEATRES, DECEMBER 9, 1944,