Jazz cognoscenti knock The Bad Plus—pianist Ethan Iverson, bassist Reid Anderson, and drummer Dave King—for lacking sincerity, thanks to the group's frequent, irreverent recasting of classic-rock warhorses such as Blondie's "Heart Of Glass" and Black Sabbath's "Iron Man." But if anything, the group's sixth studio disc is a little too reverent, not so much on the instrumentals as on the pop-song covers. Wendy Lewis, a Minneapolis vocalist, sings on eight tracks, and she, like the instrumentalists, recasts tunes like Nirvana's "Lithium," Pink Floyd's "Comfortably Numb," and Heart's "Barracuda" into jazz shapes. But where Iverson, Anderson, and King have the advantage of leaving the words behind, allowing them to shape things in any number of directions, Lewis is charged with making "Numb" or the Bee Gees' "How Deep Is Your Love"—songs whose power comes largely from their recorded contexts—into something other than doggerel. Unfortunately in those cases, she comes up short, and the players sound low on ideas.