METALHEAD MANTRA

Popular legend says the Inuit have a hundred terms for snow. Metalheads may have as many to describe their favorite breeds of evil. Delineating the differences between the hyphenated genres doom-metal, black-metal, sludge-metal and Viking-metal may be splitting hairs, but the San Francisco duo Om (Al Cisneros, left, and Chris Hakius) cherry-picks the best elements of each to craft a gut-pummeling yet hypnotically minimalist take all its own. The barely tonal bass riffs sound like Om’s amps were attacked by wolverines, and one should expect plenty of song titles like “Unitive Knowledge of the Godhead.” But the end result is like playing a Black Sabbath 45 with the turntable set to 33 rpm: It’s a slow and bruising ride, but one surprisingly easy to get lost in. 7 p.m. Sun., Echoplex. $14. (213) 413-8200; www.attheecho.com