Plenty of metal bands coast on sheer heaviness. But for Sunn O))), being heavy is more than just a journey; it's the destination. For the past decade, the core duo of bassist Greg Anderson and guitarist Stephen O'Malley have taken the considerable metal cred of their membership in groups like Goatsnake, Khanate and Burning Witch to an abstract extreme; Sunn O)))'s cosmic, oscillating low-end experiments probe the darkest wormholes of the heavy-music universe, keying in on texture, timbre and modulation rather than riffs and beats. The twosome's unwholesome drone has grown in majesty and stature since its 2000 debut full-length, ØØ Void, and blossomed earlier this year on Monoliths & Dimensions. Sunn O)))'s seventh studio album is a rich, pulsing trance of bowel-loosening, soul-expanding ambience that includes strings, horns, piano and, um, conch shells — not to mention a vocal appearance from no less than Werner Herzog.