one of the first to integrate the sound into a basic rock structure. In By Numbers the group's style had scaled back to more standard rock, but synthesisers regained prominence on Face Dances. Townshend and Entwistle were instrumental in making extreme volumes and distortion standard rock practices. The Who were early adopters of Marshall Amplification. Entwistle was the first member to get two 4×12 speaker cabinets, quickly followed by Townshend. The group used feedback as part of their guitar sound, both live and in the studio. In 1967, Townshend changed to using Sound City amplifiers, customised by Dave Reeves, then in 1970 to Hiwatt. The group were the first to use 1000-watt PA systems for live gigs, which led to competition from bands such as the Rolling Stones and Pink Floyd. Throughout their careers, the members of the Who have said their live sound has never been captured as they wished on record. Live gigs and the audience have always been important to the group. "Irish" Jack Lyons said, "The Who weren't a joke, they were fucking real, and so were we." Vocals Daltrey initially based his style on Motown and rock and roll, but from Tommy onwards he tackled a wider range of styles. His trademark sound with the band, as noted in 1983, has been a characteristic scream, as heard at the end of "Won't Get Fooled Again". Group backing vocals are prominent in the Who. After "I Can't Explain" used session men for backing vocals, Townshend and Entwistle resolved to do better themselves on subsequent releases, producing strong backing harmonies. Daltrey, Townshend and Entwistle sang lead on various songs, and occasionally Moon joined in. Who's Next featured Daltrey and Townshend sharing the lead vocals on several songs, and biographer Dave Marsh considers the contrast between Daltrey's strong, guttural tone and Townshend's higher and gentler sound to be one of the album's highlights. Daltrey's voice is negatively affected by marijuana smoke, to which he says he is allergic. On 20 May 2015, during a Who concert at Nassau Coliseum, he smelled a joint burning and told the smoker to put it out or "the show will be over". The fan obliged, without taking Pete Townshend's advice that "the quickest way" to extinguish a joint is "up your fucking arse". Guitars Townshend considered himself less technical than guitarists such as Eric Clapton and Jeff Beck and wanted to stand