Symphonic metal has its appeal, but in order to be fully immersed in, say, Blind Guardian’s swashbuckling, orc-slaying Middle-earth, or to sing along to one of Manowar’s pagan devotionals, you have to suspend some disbelief. D.C.’s Caverns engages with power-metal themes without whisking you to a Tor Books fantasyland. That’s mainly because Caverns dispenses with vocals entirely, but though there’s nary a melodic howl on the band’s songs, its members aren’t shy about delivering wailing solos or other forms of triumphant riffage. Caverns’ swooping, epic piano-driven ballads explore an unexpected confluence between math-rockers and metal barbarians; the trio is a product of the local indie-rock scene, yet its more outsize exercises in rock balladry can easily appeal to leather-clad, lion-maned metal maniacs. CAVERNS PERFORMS WITH IMPERIAL CHINA AND TRUE WOMANHOOD AT 9 P.M. AT THE BLACK CAT BACKSTAGE, 1811 14TH ST. NW. $8. (202) 667-4490.