An Improved System for Theatrical Reproduction of 35mm Optical Sound

Modern advances in magnetic recording and microphone technology are employed nowadays in the sound-recording process in film production. Original recordings often contain information up to 15 kHz. The final optical track commonly goes up to 9 or 10 kHz. Recorded sound quality is better than it appears to be when judged by listening tests in commercial theaters, due to the use of the Academy curve for playback. A technique based on “dynamic noise reduction circuitry” is described. The bandwidth of the standard optical soundtrack is extended up to 10 kHz in reproduction, without objectionable film noise. Also introduced is a dynamic high-frequency energy limiter. As an option, the monaural signal can be processed into a stereophonic signal pair, adding “depth effect.” In motion-picture-production use the channel available is expanded by an additional octave, providing better reproduction. There is no compatibility problem, and old prints can be reproduced with improved quality.

Print ISSN

0361-4573

Published

1972-12

Content type

Original Research

DOI

10.5594/J08184