Each of Rosanne Cash’s best records has pursued a specific purpose: Both King’s Record Shop and Rhythm and Romance were blatant lunges for the pop charts, while Interiors nursed the emotional hangover Cash earned from a lifetime of loving without a net. What distinguishes her latest, 10 Song Demo, isn’t its spare (by Nashville standards) production, but songs so varied and unmannered that each seems to play itself. In short, it’s an exquisite cycle of songs, which is all that most of us really want out of our best writers. Don Conoscenti opens at 8:30 p.m. at the Birchmere, 3901 Mount Vernon Ave., Alexandria. $20. (703) 549-5919. (Brett Anderson)