The Black Keys are back with a return to their roots. And just in case their opening song doesn’t make that clear enough, the album’s title — “Let’s Rock” — spells out their intention. Dan Auerbach and Patrick Carney have made rock with a bluesy-funk undertone their specialty, with this influence even shining through on some of Auerbach’s production projects (see Cage the Elephant’s “Tell Me I’m Pretty”).