U2: 'We want to make the sound of the future'

Mark SavageMusic CorrespondentGetty ImagesU2 are one of the world's biggest bands, with album sales in excess of 175 millionIt's official. U2 are back in the studio making new music, after a gap of eight years.The four-piece had been on an extended break, as drummer Larry Mullen Jr recovered from neck surgery. Pompted by years of onstage damage to his "elbows, knees and neck", it stopped him recording new…