Synchrodek film/tape synchroniser

Part of collection of amateur sound synchronising equipment: Synchrodek film/tape synchroniser, 1965-1975.

One of the most successful devices that allowed amateurs to project their sound films was the Synchrodek, devised by the engineer Harry Garlick. This was connected to an 8mm projector and a tape recorder, and could be manually adjusted to control the speed of the projector so that picture and sound maintained good synchronisation. The projector was modified so that the motor control circuitry was connected to the variable resistor in the synchronizer. A flexible drive shaft also connected the projector and the Synchrodek so that it would detect the speed of the projector. The recorder used sprocketed tape, which was fed from the tape replay head via a toothed capstan on the Synchrodek and back onto the take-up spool. The tape-recorder ran at 3¾" per second (9.5 cm/sec). The Synchrodek compared the running speed of the projector with that of the tape-recorder. Any difference between the two could be corrected by moving a slider on the variable resistor, which altered the speed of the projector.

Harry Garlick first licensed his idea to a photographic firm but was so dissatisfied with the standard of the equipment it produced, that he took back the rights and made and marketed the Syncrodek himself, trading as the Craven Instrument Company.