When I first heard Josephine Foster sing, with local duo the Children's Hour a year and a half ago, I couldn't believe she hadn't already been adopted by the burgeoning "new weird America" scene: plenty of so-called acid-folk singers sound like rock vocalists trying to backtrack into a purer, more idiosyncratic style, but Foster has been idiosyncratic from the start. Unsurprisingly, the scene's since caught up with her: she's got a track on a new compilation curated by Devendra Banhart, and Born Heller, her new duo with bassist Jason Ajemian, has been turning up on bills with the likes of Six Organs of Admittance and Espers. Although I enjoyed the debut full-length from the Children's Hour, SOS JFK, the music was too sweet for Foster's vocals; Born Heller's self-titled debut (released last month on the local Locust imprint) makes it obvious that what she really thrives on is austerity. The former opera student has a startlingly clear voice, wonderfully mannered articulation, and an impeccable sense of pitch; her dark, tightly wound melodies hover within the minimal outlines sketched by her own instruments (acoustic guitar, harp, or mandolin) and Ajemian's double bass. Her timbre isn't as plush, but otherwise she sounds strikingly like Shirley Collins, the matriarch of the 1960s British folk revival. Ajemian is best known as a jazz player--he's a member of Dragons 1976 and Rob Mazurek's Black Goat Ensemble, among others--and his unusual arco strokes, contrapuntal flashes, and percussive gestures create a nice tension with Foster's spooky, delicate warble. Michael Hurley, a genuine treasure of rural Americana, headlines; Bill Bungeroth & the Armistice open. Monday, May 17, 9:30 PM, Empty Bottle, 1035 N. Western; 773-276-3600 or 800-594-8499.