As an alumnus of the late-'90s, early Warped Tour scene, Authority Zero is one of the few acts of its ilk that's not only surviving but also thriving on the underground circuit. The group has long specialized in fast, no-frills skate punk blended with reggae and a little ska. It's nowhere near as poppy as, say, 311. But the band's alternately chilled-out and amped-up jams similarly appeal to a broad cross section of live-music fans. Onstage, in fact, is where the group is particularly beloved, reflected by the fact that its newest release, Less Rhythm, More Booze, is a live CD/DVD set. For this show at Respectable Street, Authority Zero even comes partnered with fellow ska-punk lifers, Southern California's Voodoo Glow Skulls.