An alt-rock institution finds sure footing and fresh starts with producer Danger Mouse. For a big-ticket band, the Chili Peppers remain appealingly stripped-down, mixing their lean, punky approach with disco (“Go Robot”), golden-age hip-hop (“The Getaway”), psychedelia (“This Ticonderoga,” “Detroit”), and slow-burning funk (the Elton John-featuring “Sick Love”). As with the rest of the band’s post-Californication phase, the sound remains rhythmic (credit the skeleton-key wrecking crew of Flea and drummer Chad Smith) but the mood is melancholic, introverted, and a little lovelorn—the reflections of party boys reckoning the bittersweetness of middle age.