From the New York Times Magazine:
When I asked Anderson about Sunn0)))’s stage theatrics, his response was almost Warholian in its mastery of spin, laying claim to absolute sincerity while playfully allowing that a certain degree of camp might be involved. What about the robes? I asked. Anderson frowned. “The robe makes it easier for me, personally, just to forget about the audience and concentrate on what’s going on onstage — the chemistry, the tones, the sounds.” What about the fog machines? “The idea is that this is a ritual, somehow: not a ‘gig,’ not a concert, but a sort of invocation. That shifts the expectations of the audience.” What about the final track on “Black One,” the band’s breakout 2005 album, for which one guest vocalist, the legendary “suicidal metal” recluse known only as Malefic, supposedly recorded his vocals while sealed inside a coffin? This, finally, prompted Anderson to smile.
“That was about capturing a certain kind of claustrophobic, isolated tone. There was actually a hearse parked outside the studio — a Cadillac hearse, painted purple — that belonged to the studio owner. So, we’re like, well of course we have to put the coffin in the hearse! So we actually put contact mikes inside the hearse, and inside the coffin and on top of it, and shut the lid. Malefic’s a tall, lanky guy, and he didn’t really fit inside too well. Eventually he started feeling claustrophobic, and that’s how we got the tone we wanted. There are outtakes of him knocking on the lid, saying: ‘O.K., I’m done! Let me out!’ ” Might that not qualify as tongue-in-cheek? I asked. “Tone first,” Anderson said, holding up a finger. “What this group’s about is tone.” He watched me closely for a moment, then his smile suddenly widened. “I love metal,” he said, as if confessing a closely guarded secret.
Here.