If you think traditional American folk music is all about frogs and mama, go out and buy the American Anthology of Folk Music. Sex and violence are at the heart of our folk tradition, folks. But if the '60s revival did occasionally glance down at these darker roots, it more often set its sights on contemporary social struggles, forever associating the acoustic guitar with peace and justice. Three decades later the local acoustic scene has produced a number of ("post-")folk stars who mess with our ideas of what strumming sans amplifier should be about, including the Mason Jennings Band and Brenda Weiler. (Both, with any luck, will become giant pop stars in a few minutes.) Still, only singer-songwriter Pablo revives folk's first-person-narrative tradition of sex and violence, and he manages to do so without sounding either exhibitionist or boastful. He has a remarkable vocal range with a throat affectation that's in Dylan's tradition, not his style. Pablo's melodies sound like they've been thrown down a flight of stairs, jumping scores of notes, sometimes in a single syllable. "Goddamn the agile sexless dreams of imperfect history," he quavers at one point on his agile, sexful 1998 album, Vulgar Modalities. You tell it, brother.