Consumer Electronics

SOUND TRACK

A sound track is a narrow strip of exposed film beside the image on a motion picture film, as illustrated in Fig. 27.1. The density of the track varies in accordance with the amplitude of the recorded audio signal. Although persistence of vision is adequate at an exposure rate of 16 frames per second, a film with a sound track is exposed at the rate of 24 frames per second. This increase in film speed permits recording of comparatively high audio frequencies. Original picture and sound takes are generally recorded on separate strips of film to facilitate editing of both the picture and sound material. In the final stage of production, the sound track with its changes and dubs is exposed on a film strip along with the edited picture ...