A sound projector for motion picture film wherein the standard distance between film frames and the corresponding portions of the sound track is maintained during rewinding of film onto the supply reel, even if the film is damaged in the region of several successive perforations. The film which is being withdrawn from the takeup reel engages a sprocket prior to passing around a drum forming part of the sound reproducing unit. The film thereupon reengages the sprocket before it reaches the film gate. Two spring-biased rollers tension the film between the drum and the sprocket. When the motor for the sprocket is operated in reverse, a slide engages and holds the shafts of tensioning rollers in predetermined positions to thus insure that a portion of recorded sound is adjacent to the drum while the corresponding film frame registers with the film gate.