Journal of the Society of Motion Picture Engineers (1930-1949)

Record Details:

Title:
Journal of the Society of Motion Picture Engineers
Date:
1930-1949
Publisher:
New York, N.Y. : The Society
Volume:
Journal of the Society of Motion Picture Engineers
Leaf #:
000629
Language:
English
Collection:
Technical Journals
Format:
Periodicals
Contributor:
Prelinger Library
Sponsor:
MSN
Coordinator:
Media History Digital Library
Description:
The Journal of the Society of Motion Picture Engineers (SMPE)Êdocuments the technological progress of the film industry, highlighting technical developments in production and exhibition. Of special interest are articles about special effects, theater practices, lighting, and the introduction of the 16mm format. Initially titled "Transactions of the Journal of the Society of Motion Picture Engineers."Digitized by the Prelinger Library and the Library of Congress Motion Picture, Broadcasting and Recorded Sound Division.
Date Added:
July 19, 2022
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612 Louis MALTER [j. s. M. P. E. of the quality of reproduction at various angles to the normal. The ideal characteristic is that in which the intensity is uniform for all frequencies throughout the angle denned by the entire audience in a theater at the center of the speaker mouth and which then falls off to zero very sharply outside this angle. 4. Efficiency. The absolute efficiency of a loudspeaker is defined as the ratio of the total acoustic power radiated by the loudspeaker to the total acoustic power radiated by an ideal loudspeaker if fed from the same electrical source. FIG. 1. Horn type loudspeaker (left) ; directional baffle type loudspeaker (right). 5. Input power capacity. The input power capacity of a loudspeaker is measured by the value e* of — where e is the maximum open circuit voltage which can be impressed upon the loudspeaker f terminals without producing noticeable distortion, and r is a resistance equal in magnitude to the impedance to which the speaker is designed to be connected. LOUDSPEAKER MEASUREMENTS In order to obtain an accurate and absolute comparison between the performance of the "directional baffle type" loudspeaker and the horn type loudspeaker, frequency response characteristics of the most widely used type of directional baffle type loudspeaker and of the most widely used type of horn loudspeaker were obtained in the following way.