PREVIEW Nachtmystium, Chicago's premier experimental black metallers, are on their fourth album with Assassins: Black Meddle, Part 1 (Century Media). Beyond the surface punning and musical nods to Pink Floyd — "One of These Nights" is the black mirror reflection of "One of These Days" from Meddle (Capitol, 1971) — the Chicago foursome seem to be out to offend the sensibilities of black metal traditionalists with spacious production, electronic scribbles, bluesy solos, and a deeply epic scope. It might be an attempt to escape the pall that their indirect association with NSBM — that's "national Socialist black metal" or "Nazi metal" to you — temporarily cast on their rising cachet with hipsters (Black Meddle got a Best New Music nod from Pitchfork at the time of its release).

Blake Judd, Jeff Wilson, John Necromancer, and Zack Simmons have gone out of their way to dissociate themselves with politically motivated music, but it's still tricky territory. In the search for more extreme, more dubiously authentic sounds, where can one find the line in the sand? It's like seeing a Burzum patch on the Gossip guitarist's hoodie: that's not simple irony, accepting something to express a deeper rejection, right? In the case of a band like Nachtmystium, there's the question of whether its aesthetic is inherently bound up with black metal's anti-Semitic history, or whether the path it's pursuing — cutting across classic rock and even classical tropes — messes with the smooth functioning of this equivalence mechanism.

Nachtmystium shares a bill with Wolves in the Throne Room — a band of cooperative-farm-dwelling radical ecologists whose relationship to black metal's aesthetic/political orientations is more obviously strained, but is equally provocative. Don't worry — there's still time to bury your going-out clothes in the earth and arrive at the show smelling like decay.

NACHTMYSTIUM With Wolves in the Throne Room, Saros, and Embers. Sun/12, 8 p.m., $12. Oakland Metro Operahouse, 630 Third St., Oakl. www.oaklandmetro.org