Chavela Vargas made her Carnegie Hall debut in 2003 at age 83, and the audience fed on her performance like they'd been thrown meat after decades of marshmallow fluff. Which, in a sense, they had. No focus group, no producer could come up with the Chavela Vargas recipe, which involves transforming the ravages of time, boozing and womanizing into songs that hit the listener like a gnarled tree branch jutting out of the speakers. Vargas at 83 is more alive, more passionate than all the prefab teen pop bands crooning for big bucks on the radio. She's a disappearing breed; listen and learn.