Other Users of ADT
Townsend's technique, and minor variations on it, quickly caught on and almost immediately began to be used by other artists and record producers. Former Beatles engineer Norman Smith used ADT extensively on Pink Floyd's debut album The Piper at the Gates of Dawn, recorded at Abbey Road in 1967. As well as using it for more conventional simulated double tracking, Smith made much use of the technique to split Syd Barrett's vocals between the stereo channels. In some cases, Smith (or possibly Barrett himself) used such extraordinarily wide ADT in this way as to give the slightly disorientating impression of not so much double tracking but two quite separate voices on either channel wildly out of time with each other – the best example of this is perhaps on "Bike". Similar effects were later used on some of Barrett's solo works, perhaps indicating his fondness for this unusual use of ADT. Pink Floyd themselves continued to use ADT on most, if not all, of their subsequent albums up until the 1980s, with one notable use being on "Alan's Psychedelic Breakfast", where a part of the drum track is treated with ADT.
In the US, Simon and Garfunkel began to use ADT on stereo mixes of their songs to split vocal tracks between the channels, examples of which include "Mrs. Robinson" and "Cecilia".
Gary Kellgren, Jimi Hendrix's engineer, made extensive use of ADT on all of Jimi's albums, frequently using the technique to split vocal, guitar, and even drum parts between the stereo channels.
Read more about this topic: Automatic Double Tracking