"With the U2 sound and Edge's guitar rig, there's sort of orchestration that comes with our songs, and Rick was saying 'What would it be like to just hear things just raw?' Bono said in an interview with KROQ (a Radio.com station) morning show hosts Kevin & Bean.

"So when we put out this album with iTunes, we also put out an album, a physical release where we have acoustic versions of those songs and some people prefer them, which is interesting. And we've been going around the world playing them and we're going to play certainly a few."