Audio Performance of Magnetic Prestriped Super-8 Motion-Picture Films

Audio engineers who design magnetic record and playback equipment for magnetic prestriped super-8 motion-picture films require a knowledge of the magnetic and electroacoustic properties of the film for optimum system design. Although all of our prestripes have similar inherent magnetic properties, the resultant audio data depend upon whether an 8mm or 16mm format is tested. The different film velocities, record track widths, and equalization standards involved with these formats have a significant effect on the audio performance. The scope of this paper is therefore limited to the super-8 films. In an attempt to help guide the equipment designers and customers, we have chosen to present the properties of our prestripes in an absolute manner whenever possible, as well as to report the conventional measurements relative to a specific reference. Shortcircuit flux values are given to permit calculation of the actual head output voltages to be expected. Furthermore, the intermodulation and harmonic distortion measurements, and the saturation output levels relative to an absolute shortcircuit flux level, provide additional data to predict the recording quality obtainable from the magnetic prestripe. For convenience in a qualitative appraisal, the prestripes are also compared on a relative basis with a full-width coated magnetic film. The Eastman Kodak Co. prestriped super-8 film audio output, frequency response, and surface characteristics are shown to be similar to those of good-quality audiotape.

Print ISSN

0361-4573

Published

1975-04

Content type

Original Research

DOI

10.5594/J13373