Denver lost a mighty source of rock power the day the Volts disbanded. From 1991 to 2002, the quartet -- led by the circuit-blowing vocalist J.R. Spiegel -- was as forceful as its name, fusing rowdy Oi! and sleazy street punk into a single, sizzling shock. When Spiegel left Colorado for New York last year, the three remaining Volts resurrected themselves as Los Muertos (playing Saturday, August 23, at the Climax Lounge, with Flash Express and Black Black Ocean). With bassist Brandon Richier now assuming microphone duty, there's more room on stage for Cesar Gomez's lightning-sharp guitar; he wields his Les Paul like a cattle prod, spitting out stinging jolts of blues-punk giddyap. The group's dynamo, though, is drummer Carlos Becerra, who pounds kilowatts of raw energy out of his skins. And where the band previously had more of an abusive, abrasive edge, prickling with a high-strung intensity, this new incarnation focuses more on melody, harmony and the earth-swallowing heaviness of sheer rock and roll. The Volts may be dead, but long live Los Muertos.