Among his peers in Nashville, singer/songwriter David Olney is renowned for his trenchant lyrics, eclectic musicianship, and ability to be both artful and accessible. After three decades, Olney’s grizzled baritone and acoustic-based sound have gained luster and gravitas. Growing older hasn’t unduly mellowed him; the streak of the stubborn outsider remains strong in his work. “When the Deal Goes Down” and “Big Blue Hole” are indicative of his dark, slightly morbid vision (as well as his penchant to rock out when he chooses). A fascination with biblical themes informs songs like “Servant, Job” (a sly dialogue between God and the devil done up big-band style) and “Scarecrow Man” (a brooding parable cast in folk ballad form). There’s a hard-won wisdom to these tunes, heard most clearly in “No Trace,” a quiet protest against “progress” set to a warm Spanish melody. Musically, Olney balances earthiness and sophistication as he shifts between elegant jazz (“Why So Blue?”), gritty blues (“Roll This Stone”), and melancholy waltzes (“Sad Saturday Night”) with a veteran troubadour’s easy assurance.