If for some incomprehensible reason you're feeling down on the Chicago music scene, the fact that you can see Jeff Parker play for free every Tuesday night in the heart of Wicker Park should cheer you up. Parker, renowned as a member of Tortoise and a fixture on the local improvised music scene, isn't a particularly flashy guitarist, and his controlled approach can initially seem underwhelming, but give him some time: during the course of an evening at Rodan, a relaxed conversation among Parker, bassist Josh Abrahms, and Tortoise drummer John Herndon develops almost imperceptibly, with virtuoso pyrotechnics foregone in favor of subtly evolving textures and rhythms.