Jay Clayton sings smart, not pretty: she abjures the vibrato that most jazz and pop vocalists use as a matter of course, and in the studio she avoids reverb, sweetening, and all the other technological crutches that could provide her voice with artificial warmth or a gauzy cover-up. But it's not those decisions that make her a different kind of singer; it's her desire to sing differently that's led her to those decisions. Even when she tackles an entire album of standard ballads--like the 1995 Beautiful Love (Sunnyside), with pianist Fred Hersch--Clayton remains cool, though not necessarily calm, keeping her distance from the emotion in her material. This somewhat intellectualized stance reflects her considerable experience in two genres that tend to emphasize theoretical concerns: postbop jazz and contemporary classical music. I can't think of another singer who can so deftly handle both hard-swinging improvisation and the rigors of 20th-century composition, from serialism to expressionism to minimalism--all of which Clayton has recorded. (A particularly good example is her work on the original recording of Steve Reich's haunting Tehillim.) Such an approach doesn't lend itself well to an all-standards program like Beautiful Love, though; the mix on the 1997 album Circle Dancing--original compositions by Clayton and her associates, peppered with the occasional familiar tune--serves her strengths much better. Her own songs match arioso vocal lines with either trumpet or alto sax, and she occasionally makes inventive use of overdubbing: on one piece, rather than simply providing her own backup parts or harmonizing with herself, she sings two or three independent contrapuntal lines, creates clashing rhythmic accents, and ululates like a siren behind a front-and-center spoken lyric. Throughout the record Clayton negotiates hairpin turns of melody and mood with such speed and precision that she seems to defy physical law; with this remarkable control she can communicate complex emotions and ideas that bluesy bathos or pop-diva histrionics just can't reach. Wednesday, 8 PM, HotHouse, 31 E. Balbo; 312-362-9707.