Preparation was extensive: first Grohl had his usual start-off by developing demos with drummer Taylor Hawkins, but for the first time Grohl tried to input vocals and lyrics in this early composition stage. After rounding up composition with guitarist Chris Shiflett and bassist Nate Mendel, Grohl spent two weeks with Norton discussing "arrangements, harmony and melody" and reducing the song ideas, and then the band spent four weeks rehearsing, playing "a song a day, from noon to midnight". Hawkins stated that "we basically played each of these songs 100 different times, trying every little thing every different way" and that it was the first time since "The Colour and the Shape" "that Dave had to deal with someone in the room questioning all his ideas", given the more laid-back approach of previous producer Nick Raskulinecz. Grohl claimed the choices were for the "most powerful, dramatic songs", and that there was an effort to "make everything sound as natural as possible – just like on the albums we grew up listening to", citing 1970s artists such as Neil Young and Wings as a major influence. Shiflett added that for the first time he played lead guitar in some tracks while Grohl "usually works out all the bits" of composition.