Ken Townsend

Ken Townsend MBE is an English sound engineer who played an important role at Abbey Road Studios. He worked on several Beatles albums, such as "Rubber Soul", "Revolver" and "Sgt. Pepper's Lonely Hearts Club Band". In 1966 he invented artificial double tracking (ADT). He spent his whole working career at EMI, and retired as the Chairman of the Studio Group after 42 years of service.
ADT.
During the recording of "Tomorrow Never Knows", Lennon complained that he had always hated doing a second take to double the sound of his vocals, so Townsend, the studio technical manager, created the world's first ADT system by taking the signal from the playback and recording heads and delaying them slightly, thereby creating two sound images from the original signal. By altering the speed and frequencies he could also create other different types of effects, which The Beatles used throughout the recording of "Revolver".