SOUND-ON-DISC

The term 'Sound-on-disc' refers to a class of sound film processes utilizing a phonograph or other disc to record or playback sound in sync with a motion picture. Early sound-on-disc systems used a mechanical interlock with the film projector, while more recent systems use timecode.
Sound-on-disc processes:

★ Vitaphone introduced by Warner Brothers in 1926

★ Phono-Kinema short-lived system invented by Orlando Kellum

★ Digital Theater Sound