Corn-fed blues-rock duo The Black Keys redefine their indomitable sound on their latest studio venture, Attack & Release. The record stands as the Keys’ most adventurous and poignant album to date, featuring broadened instrumentation, psychedelic and trip-hop backbeats, and a whole lot of electronics. Fans of their former, filthier pursuits will undoubtedly be taken aback. The change here is due partly to the Keys’ collaboration with producer Brian “Danger Mouse” Burton, whose mixing method drips its polished sound all over the Keys’ gritty tunes. Fans will scoff at the album’s mid-fi attempt at Delta grime. But like it or not, The Black Keys make a resounding statement in their pseudo-requiem. It’s true, “Things Ain’t Like They Used to Be.”