Motion Picture Herald (Jul-Aug 1940)

detteahedtres JULY 27 Vol. 140 19 4 0 No. 4 ... a section of Motion Picture Herald devoted to the physical theatre, published by the Quigley Publishing Company, Inc., Rockefeller Center, New York, every fourth week. Martin Quigley, publisher and editor-in-chief. George Schutz, editor. Colvin Brown, general manager. Ray Gallo, advertising manager. C. B. O'Neill, Western advertising manager, 624 S. Michigan Ave., Chicago. London Bureau: No. 4, Golden Square, Wl. Consultants: J. T. Knight, Jr., physical operation; Ben Schlanger, architectural form: C. C. Potwin, acoustic design and treatment. ■ ■ ■ That Rear Wall Acoustic Puzzle indicative of the direct interest that is being taken by Hollywood these days in the facilities of the theatre to present its product effectively, is a letter received early this month from the Research Council of the Academy of Motion Picture Arts & Sciences, raising a question regarding the acoustical disposition of rear auditorium walls as dealt with by C. C. Potwin in a group of diagrams in the June 1st issue. The letter, addressed to Mr. Potwin, with a copy to Better Theatres, discusses a matter of critical importance in sound reception therefore the points presented in it by Jack Durst, chairman of the Council's subcommittee on acoustical characteristics, and Mr. Potwin's reply should be of general interest; indeed, the correspondence goes far in clearing up an issue that has been confused for some time. ►Admitting that the control of reflections "has unlimited possibilities," Mr. Durst states the belief of his committee that the principal benefit of such control lies in the direction of these reflections away from the audience rather than towards it. He upper. WALL VlfcW OFHORIZONTAL WALL FORM5 ... WAINSCOT AHEA 7 5' FLOORS specifically refers to the drawing at the upper right-hand corner of page 13 in the June 1st issue. "This," he points out, "indicates the reflected sound would be directed towards the ceiling and away from the audience, while in the upper left-hand corner of the same page (both drawings are repeated here) the sloping portion between the upper wall and wainscoting is angled in the opposite direction and would, therefore, tend to reflect sound towards the audience, unless the degree of slope is greater than might possibly be interpreted by the proportions in the drawing. The same is true of the rear wall contours shown on the same page. "We have recently had the misfortune to have one of our newest preview theatres in this vicinity designed on the premise that controlled reflections from the rear wall would serve a useful purpose in reinforcing the sound energy at the rear of the theatre. "As a result, this theatre presents an extremely difficult problem in the adjustment of its acoustical response characteristic. The reinforcement obtained in the rear section is far from imaginary, but unfortunately is entirely below 500 cycles and is of uneven phase distribution. "The net result is a definite 'muddiness' in the low frequencies, and a very disturbing lack of presence \liveness and fidelity of sound] in the seating area concerned. When the characteristic is altered sufficiently to obtain even a small degree of presence in the rear section, the center and front sections of the house are highly objectionable from over-emphasis of this part of the frequency spectrum." Formaiion of the Wall When Tilted In reply, Mr. Potwin cites these factors : 1. In auditoriums zvith amplified sound, in which the sound system itself can be adjusted to supply sufficient volume at rear rows, tilting of the rear wall to reflect sound into the audience is usually to be avoided. 2. Should an auditorium require such reflection into the audience (as might be the case in a very deep auditorium) , this can be done by tilting the rear wall inward so that broken-up reflections may be absorbed quickly in the audience area. 3. The wall so tilted inward should not be a large, plain surface. ►"I refer to my column," continues Mr. Potwin, "in the issue of July 22, 1939, in which I discussed rear wall formation and the usual necessity for designing this surface in a series of small slopes superim posed on the main slope in order that proper diffusion may be obtained. . . . "The inward slopes for the rear wall shown in the sketches in the June 1, 1940 issue are a group of small slopes which in the final design would vary in size, dimension and degree of projection from the fundamental slope. . . . ►"With respect to the inward tilt just above the wainscot area along the side walls, this surface is usually not greater than 2 feet in height above a 4 or 5-foot wainscot, and is varied in the degree of projection from the vertical, depending on the size of the floor plan. Its purpose is fundamentally a practical one due to the fact that lower wall areas are easily reached by the audience. A truly vertical wainscot of hard material 6 or 7 feet in height along the side walls frequently produces objectionable reflections. The 2-foot inward tilt has been used both advantageously and successfully in actual theatre design work." Display Methods Yet another recent communication merits being passed on to readers. This one, from Ernest Wagner of Wagner Sign Service, Inc., Chicago, offers, with the aid of an interesting sequence of photographs, some instructive comment on marquee advertising. Referring to Better Theatres' publication during the past year of considerable material on carefully planned arrangements of marquee copy (we've applied the term "typographical" to the method, to indicate a certain relationship to printed advertising), Mr. Wagner goes on to say: "I have noted with interest the series of drawings showing different copy ar 7