U2 frontman Bono was disappointed by the relatively poor sales of the band's last album NO LINE ON THE HORIZON, insisting the record was too "challenging" for fans.
Despite selling more than one million copies following its release earlier this year (09), No Line on the Horizon only produced two singles, which both failed to break the top ten in the U.K. song charts.
And Bono blames the music tastes of the album-buying public for the lack of interest - because they are used to simple pop songs rather than real rock releases.
He tells Spinner.com, "We weren't really in that mindset and we felt that the album was a kind of an almost extinct species, and we should approach it in totality and create a mood and a feeling, and a beginning, middle and an end.
"And I suppose we've made a work that is a bit challenging for people who have grown up on a diet of pop stars."