Deborah Voigt is a down-to-earth-diva, part girl next door, part party animal, part everyone's favorite raunchy aunt -- a dash of Wagnerian goddess Birgit Nilsson, a pinch of Anna Nicole Smith, a few shakes of Bette Midler. It's fun to be in her company even when she isn't singing. After singing William Bolcom's naughty morning-after song, ''Toothbrush Time," she said, ''My mother would be so proud." And when someone's cellphone went off she went scrambling for the phone in the voluminous folds of a glamour gown designed to show off her new slimline waist.
Voigt's voice may not be rich and colorful, but it is big, exciting, and secure all the way up to the blazing high C that capped her last encore, ''I Could Have Danced All Night." It was also a treat to hear an American prima donna singing most of her program in English, all the way from Amy Beach and Ives to Stephen Sondheim and her friend Ben Moore, who writes pretty songs that lie on the border between art song and parlor ballad. You can understand every word she sings, which is not always to her advantage when she loses her way, which she occasionally did, or even when she reverses the meaning, which happened in ''Can't Help Lovin' Dat Man," when she sang, ''When he goes away, that's a happy day."
Voigt did sing three songs by Richard Strauss with radiant tone and idiomatic German diction, and two Tchaikovsky songs powerfully characterized in Russian.
At the piano, Brian Zeger was attentive, stylish, and in the quieter music, full of subtlety; he hits a wall when he bangs for volume.
Voigt proved especially skillful in adapting her operatic instrument to cabaret and show material. She was overwhelming in ''Losing My Mind" from ''Follies" because she planned it so well and felt it so deeply; Sondheim's ribald ''I Never Do Anything Twice" was hilarious because she didn't overdo it. Encores were by Strauss (''Zueignung," exultantly flung out), Kern, Lerner & Loewe, and Ben Moore, again -- ''Wagner Roles," written especially for Voigt, with a reference to the ''little black dress" she couldn't fit into a few years ago, costing her a job. The song plays for philistine laughs at Wagner's expense, but, coming from her, it's fun; she ought to know.