THE MAYAN CALENDAR has nearly reached its end—so naturally, it's high time for Sunn O))) to dry clean their robes and warm up their 17 amplifier stacks. Their latest apocalyptic roadtrip down the coast leads up to a doomy celebration of the end of times at the mouth of hell itself (AKA Los Angeles) with High on Fire, Corrosion of Conformity, and others, during which they'll sacrifice a crusty kid and dance on their bloody His Hero Is Gone patches.

Or at least that's what you'd think.

"Honestly," Sunn O)))'s Greg Anderson clarifies, "I don't personally believe in [the Mayan calendar]." With a self-deprecating chuckle, he adds that it's just "an excuse for some sort of a dark, negative celebration." Anderson, part of the core duo of the group's seemingly boundless stable of players, cuts through the machined fog with a dry candor that belies his monolithic musical project. "There's no specific or focused religious ideology within the group," he says. "That question gets asked a lot, about what's the religious angle of Sunn O))), or the spiritual aspect of what we're doing."

Sunn O))) made a name for themselves in the early 2000s with a distillation of metal's most basic element: the riff. There are no beats or solos, no breakdowns or harmonies, just the searing, ever-present, droning riff.

Despite unleashing sonic assaults that are worthy of soundtracking Cannibal Holocaust, Sunn O))) come across as well-adjusted, down-to-earth folks. "Sunn O))) strives to be as ego-less as possible. Stephen [O'Malley] and I strive to leave that outside of what we're doing," Anderson says. He hints at the usual creative dysfunction in the group—but he leaves the overwhelming impression that their tormented sludgescapes exist as the result of impassioned collaborators and even-keeled temperaments.

Sunn O)))'s list of collaborators reads like a fanboy's fever dream: Attila Csihar of Mayhem, Malefic of Xasthur, Justin Broadrick of Jesu/Napalm Death/Godflesh, Boris, and Dylan Carlson of Earth have all lent their aural terror to Sunn O)))'s recorded output—not to mention Sun Ra cohort Julian Priester, featured on Monoliths and Dimensions' spiraling tribute to Alice Coltrane, "Alice." One of their more infamous pairings features Julian Cope incanting a 20-minute tale about Sunn O))) principals Anderson and O'Malley roaming medieval valleys, "[purveying] a sonic doom."

Anderson doesn't bat an eye at the outrageous list. "It happens naturally, you know," he says. "There's nothing specific that we look for, it just happens."

The constant flow of outside influence keeps the band's sub-100 Hz drone from becoming just noise—their most recent full-length, 2009's Monoliths and Dimensions, both honed in on their trademark sound and expanded outward with instrumentation new to the Sunn O))) sound. The record moved past their old method of "just Stephen and me playing riffs together," as Anderson says. Opener "Aghartha" begins with Attila Csihar's slow-creep story of inner-Earth cities and expands, eventually incorporating what sounds like the studio walls bending to the point of snapping from the power of Sunn O)))'s riffs.

Even for a band whose metronomes measure in beats per hour, Sunn O))) has taken an unusually languid victory lap since Monoliths. Sunn O))) the live band has replaced Sunn O))) the studio project for almost four years now, and the members don't seem pressed to change the current state of affairs. "There hasn't really been anything discussed," says Anderson. For Sunn O))), flux seems the only productive mode of operation. Anderson can't be bothered when he says, "It's up in the air."