Although past Black Keys recordings featured post-blues minimalism at its finest, the rawness of one disc after another threatened to become a stylistic dead end. Enter Brian Burton, aka Danger Mouse, whose work on the Keys' latest CD, Attack & Release, opens up new sonic vistas for the duo. Singer/guitarist Dan Auerbach and drummer Patrick Carney haven't lost their taste for heavy riffing, as tunes such as "Strange Times" demonstrate. But under Danger Mouse's supervision, they expand their palette on "All You Ever Wanted," a country-flavored lope enlivened by flavorful organ playing, and "Things Ain't Like They Used to Be," a wide-screen offering that's as emotionally rich as anything Auerbach and Carney have conceived to date. It's tough to know how the tandem, appearing at this show with Jay Reatard, will convey these advances in a live setting, since their production partner won't be sitting at the soundboard. Still, the new material offers Keys for the future.