Film with light sound track carrying the stereophonic sound information;

Abstract

A film with a light-sound track carrying stereophonic sound information and a ribbon light valve for producing the light-sound track, and a light-sound transducer for reproducing the information recorded on the light-sound track. On the film, the sounds of two stereophonic channels are recorded in a single light-sound track in the form of an envelope asymmetric to the longitudinal axis of the light-sound track. The ribbon light valve has a light gate controllable by a ribbon arranged in a magnetic field; to the terminals of the two series-connected ribbons a transformer is connected. To the terminals connected with the transformer, two series-connected resistances are connected and, between the junction of the two resistances and the junction of the two ribbons, a further transformer is connected. The light-sound transducer has two light sensing elements, and electric terminals for tapping separately the signals of the two light sensing elements. On the light-sound track, the stereophonic sound of a compatible recording system can be recorded and the film can be projected with a monosound projecting apparatus.