on 10 february 1967 during the recording of "a day in the life", ken townsend synchronised two machines so that extra tracks were available for recording the orchestra. speaking in an interview with australia's abc, geoff emerick described the technique; emi tape machines' speed could be controlled using an external speed controller which adjusted the frequency of the mains supply to the motor. by using the same controller to control two machines, they were synchronised. townsend thereby effectively used pilottone, a technique that was common in 16mm news gathering whereby a 50/60 hz tone was sent from the movie camera to a tape recorder during filming in order to achieve lip-synch sound recording. with the simple tone used for "a day in the life", the start position was marked with a wax pencil on the two machines and the tape operator had to align the tapes by eye and attempt to press play and record simultaneously for each take.