Oleta Adams' 15 years as a Kansas City jazz nightclub act probably didn't prepare her for the pop success she's now enjoying. Her debut album, Circle of One, has moved into the top 20 some eight months after its release. It may have taken this long to catch on because it's a gentle album dominated by sparse arrangements mostly just piano, bass, and drums, which reflect Adams' gospel roots. Her voice can soar with intensity, hanging onto notes for dear life, or suddenly drop into hushed intimacy. Adams' top 10 hit, ''Get Here,'' is an unrushed call to her lover, while her upcoming single, the album's title track, is a rumbling declaration of hope, punctuated by jingling bells and backing vocals that ring out with muscular joy. Although the music on the album is a little too smooth, Adams' voice roams freely, imbuing the collection with depth and warmth.