Garage-blues duo the Black Keys tackle their newest single with trademark minimalism, and the result is hard-hitting, retro-rock gold. "Tighten Up" reunites the band with Danger Mouse, who produced its 2008 album "Attack & Release." The song establishes a solid bass drive from the start, backed by a cheery whistled accompaniment. Singer Dan Auerbach's vocals are colored with a Gnarls Barkley-esque quality that's bolstered by the song's melody, a more soulful one than those found on older Keys material. Auerbach's springy skank guitar provides plenty of punch to complement drummer Patrick Carney's direct rhythmic approach, making the track easy to groove to upon first listen. "Tighten up on your reins, you're runnin' wild," he howls, fitting words for a raucous jam that seems set to break loose at any moment.