James spent six hours per day jamming on ideas for songs across six or seven jam sessions – all of which they recorded. The band intended to go back to the jams and shape them into song structures. After Booth wrote lyrics, James planned to work with a producer who could bring another perspective to the material. Booth brought in engineer Beni Giles during the second week of pre-production to help record the jams. When he was writing "Heads", Booth asked Giles to alter the drums; the latter was initially hesitant as he said he was producer and not an editor. Giles came up with a part Booth really liked, and as a result of this, the band kept inviting Giles to the jam sessions. James accumulated over 100 jam recordings, and took around 10 of them home to continue working on. Trumpeter Andy Diagram was invited to join Booth in Los Angeles, California, where they edited some of the jams.
