In 1947, Paul released a song through Capitol Records that had originally begun as an experiment in his garage, titled "Lover (When You're Near Me)" which featured Paul playing eight different electric guitar parts, some of them recorded at half-speed, hence "double-fast" when played back at normal speed for the master. This was the first time that multi-tracking had been used in a recording. Amazingly, these recordings were made, not with magnetic tape, but with wax disks.
"Lover" is a popular song written by Richard Rodgers, with words by Lorenz Hart. It was featured in the movie Love Me Tonight (1932)
He built the multi-track recording with overlaid tracks, rather than parallel ones as he did later.
Paul even built his own wax-cutter assembly, based on car parts. He favored the flywheel from a Cadillac for its weight and flatness. Even in these early days, he used the wax disk setup to record parts at different speeds and with delay, resulting in his signature sound with echoes and birdsong-like guitar riffs. When he later began using magnetic tape, the major change was that he could take his recording rig on tour with him, even making episodes for his 15-minute radio show in his hotel room.
He invented the first solid-body electric guitar, the first bass guitar, the use of Echo, Delay, Reverb, Flanging and Phasing.
Perhaps the earliest commercial issue of recordings with overdubs was by RCA Victor in the late 1920s, not long after the introduction of electric microphones into the recording studio. Recordings by the late Enrico Caruso still sold well, so RCA took some of his early records made with only piano...