The chance to see Charlie Hunter anywhere in Nashville is a rarity, but at a venue as small and intimate as the Family Wash, it’s a no-brainer. Hunter plays bass and guitar parts simultaneously on his specially designed seven-string instrument (three bass strings, four guitar strings), but it’s no gimmick: He’s been recording and touring for two decades now, and he’s still one of the most compelling live performers around. He summed up the beauty of his two-instrument approach in a recent LA Times interview: “It actually simplifies things, and [allows me to] be more direct. And less desperate (laughs). Because there’s really nothing more desperate than a guitar player playing a lot of notes.” His 2010 recording Public Domain featured songs from the public domain selected by his then-99-year-old grandfather Sidney Greenman, and includes some delightful recastings of classics like “Danny Boy,” “Alexander’s Ragtime Band” and “Meet Me in St. Louis.” Still, Hunter’s best savored up close and personal, where his relentless grooves and improvisatory outbursts never fail to astound.