Those lucky enough to have caught RUTHIE FOSTER live, particularly years back when she sat in with the Austin gospel act the Imperial Golden Crown Harmonizers, know something her albums have never fully betrayed: She’s a stone soul singer who’s been masquerading as a folk act. No longer. THE PHENOMENAL RUTHIE FOSTER (Blue Corn Music) is a throwback to an era when gospel-tinged Southern soul ruled the airwaves. Decades ago it was also common to see titles like The Incredible Jimmy Smith and The Genius of Ray Charles ; while such immodesty has long been out of vogue, Foster wears it well. Her voice is a typhoon, bold and rich, with a tendency to suck up everything in the room. Though the album’s arrangements are all of a piece and the recording is thin, the playing is solid. And the song selection (originals, plus covers of Son House, Sister Rosetta Tharpe, and Lucinda Williams) is superb. Credit Harmonizer bandmate Malcolm “Papa Mali” Welbourne, who coaxed Foster back to the music of her youth by taking away her acoustic and sitting her at a Wurlitzer piano. From there, it instantly became all about the groove.