U2 began work on "Pop" in mid-1995, collaborating with Nellee Hooper in London, France, and Ireland. In September, the band moved the recording sessions to Hanover Quay in Dublin to a studio the band had just converted from a warehouse. The studio was designed to be more of a rehearsal space more than an actual studio. Flood, Howie B, Steve Osborne, and Marius de Vries joined Hooper and the band there, each of them incorporating their influences and experiences in electronic dance music. Flood described Howie's influence thus: "Howie would be playing all kinds of records to inspire the band and for them to improvise to. That could be anything from a jazz trumpet solo to a super groove funk thing, with no holds barred. We also programmed drum loops, or took things from sample CDs; anything to get the ball rolling. U2 arrive in the studio with very little finished material." These sessions lasted until December 1995, and around 30–40 pieces of music emerged during this period.