Plenty of bluegrass outfits shred as impressively as heavy metal groups, but few sing about the devil more evocatively than members of the latter genre. Nashville's celebrated Grascals manage the feat on their fourth album, "The Famous Lefty Flynn's." The 12-song set peaks early with "Satan and Grandma," a gorgeous yet surprisingly tender string-band ballad on which singer/guitarist Jamie Johnson describes his grandmother's battle with Beelzebub using "a Bible for her sword and shield." Elsewhere, the sextet appears less interested in proving itself to Black Sabbath fans, although crossover aspirations circulate throughout the album: See a tight harmony rendition of Tommy Boyce and Bobby Hart's mid-'60s Monkees hit "Last Train to Clarksville" and a down-home collaboration with Hank Williams Jr. on "I'm Blue I'm Lonesome." The latter tune was co-written by bluegrass giant Bill Monroe and Williams' country-pioneer dad, and that spirit of open-eared cooperation lives on here.-Mikael Wood