He also assisted the development of recording practices like overdubbing, sampling and reverb. This allowed for more synth overdubbing and real drum tracks. On another occasion, McCartney was overdubbing a vocal track when he began gasping for air. The soundtrack recordings underwent post-concert production featuring heavy use of overdubbing and re-sequencing. The recording involved many hours of multi-tracking and overdubbing. It was recorded mostly live with some minimal overdubbing. The piece fades out on overdubbing cascading electric guitar parts. Recording for "London Town" was completed with some final overdubbing in January 1978. Mingus's perfectionism led to extensive use of studio overdubbing techniques. Lukather recorded the album in mostly live takes with little overdubbing. Originally the Tijuana Brass was just Alpert overdubbing his own trumpet, slightly out of sync. Use of tape overdubbing was pioneered by Les Paul in the 1940s. I had purchased earlier that year, plus cello, all done by multiple overdubbing. Joining U2 in the studio, he stripped away what he thought to be excessive overdubbing. The overdubbing of the tape loops took place on 7 April.