Brooklyn-based duo Ratatat’s second album sees them aiming for a less rambunctious strain of rocktronica, to winning effect. The big, boombox-friendly beats that womped through their debut are decelerated and spaced out into subtler, more dynamic drumlines on Classics, making for slick and unobtrusive dance rhythms. Funk (“Loud Pipes”), samples (check out the feral panther growls on “Wildcat”), and slick, zooming electric guitars (“Kennedy”) are all still here in abundance, just with a little more slow to their roll.