Don't be fooled by Shelley Neill's conservative Bostonian roots or her Melanie Griffith blondeness. Beneath those sunny curls is a head for the blues and a torch-singer sensibility that echoes such faded greats as Libby Holman and Ruth Etting. Envisioned as a companion piece to Neill's estimable The Blues Run Through It, the new Envisioning Blue (Cobalt Blue) serves up saucily revitalized treatments of such varied chestnuts as "Am I Blue," "It Was Written in the Stars," "Me and the Blues" and "Now's the Time." Though the purist in me can't quite condone Neill's altered lyrics to "Comes Love" (especially since her new words add nothing different or new), her kickass "Don't Explain," swapping out Billie Holiday's victimized sorrowfulness for strident dignity, make it easy to forgive that tiny transgression. And if you thought Etta James was the only one who could quicken your pulse with a scorching "At Last," get set for a version so vigorous it could steam up the windows of Beacon Hill's frostiest mansions.