New and Old Aspects of the Origins of 96-Cycle Distortion

The work of previous investigations is reviewed and correlated with the results obtained in a comprehensive study of 96-cycle distortion due to the presence of sprocket-holes adjacent to the sound-track. This distortion has been known for some time. Much improvement has been made by the adoption of the magnetic-drive recorder, the non-slip printer, and the rotary stabilizer sound-head for the purpose of overcoming the problem of slippage. — Recording sound on doubly perforated film will introduce 96-cycle disturbances of both amplitude and frequency modulation because of the film flexure and possible variations of film speed at the sprocket-hole rate. — Processing sound records on doubly perforated film will introduce a 96-cycle hum and amplitude modulation depending upon the processing technic. — Printing sound records on doubly perforated film introduces 96-cycle hum and disturbances of both amplitude and frequency modulation, due to film flexure and variations of film speed at sprocket-hole rate. — Reproducing sound records on doubly perforated film introduces 96-cycle disturbances because of film flexure. — Since it has been proved that the presence of the sprocket-holes adjacent to the soundtrack is the source of all 96-cycle distortion, and the omission of the sprocket-holes entirely eliminates this distortion, it becomes obvious that singly perforated film should be used throughout all phases of sound recording and reproduction if complete freedom from 96-cycle distortion is to be obtained. — Substantial improvement can be realized if the singly perforated film is employed only for the original negative, master positive, and re-recorded negative, and doubly perforated film for the release prints. The use of singly perforated film throughout all phases has a decided advantage of providing additional space, without affecting the picture dimensions for a double-width sound-track or two sound-tracks, one for control or other purposes.

Print ISSN

0097-5834

Published

1941-09

Content type

Original Research

DOI

10.5594/J09967