After 29 years at the helm of the Contemporary Chamber Players, Ralph Shapey is stepping down. The group he founded will no doubt continue doing a fine job as an indispensable pluralistic advocate of modern music, but the maestro's feisty touch and sagacious guidance are likely to be missed. Shapey the composer, however, is still going strong at 72. He recently completed the broad-canvased Concerto Fantastique, which the Chicago Symphony Orchestra unveiled last season, and his newest piece, Inventions, will be premiered Friday night, at the CCP's annual Paul Fromm Concert. Scored for clarinet and percussion--whose timbres and rhythmic possibilities have sparked Shapey's imagination of late--Inventions may contain some of the stubbornly original structural ideas that the master of abstract expressionism developed in his larger orchestral composition. The three-movement piece will be performed by its dedicatee, clarinetist Edward Gilmore, who will be accompanied by percussionist Douglas Waddell. Also on the program is a local premiere of Settings for soprano and chamber orchestra by Pulitzer Prize-winner Mel Powell, a prof at Cal Arts. An example of musical haute couture, this 1979 work includes texts by James Joyce, Milton, and Euripides and the music conveys a sense of quiet desperation that eventually leads to spiritual liberation. Diane Ragains is the soloist. The under-40 generation will be represented by a piece from Osvaldo Golijov of Argentina. His string quartet Yiddishbbuk is a loose reconstruction of some ancient apocryphal psalms collected by Franz Kafka while he was living in Prague. Its movements commemorate Isaac Bashevis Singer, Leonard Bernstein, and children interned by the Nazis. The "classic" on the program is Schoenberg's Ode to Napoleon for reciter, string quartet, and piano--a telling choice, perhaps, given Shapey's Napoleonic stature. Its text, part of a Lord Byron poem, will be recited by Jeffrey Strauss. This concert is dedicated to Howard Brown, an astute musicologist who trained generations of scholars at the University of Chicago and enriched the city's early-music scene. Friday, 8 PM, Mandel Hall, University of Chicago, 1131 E. 57th; 702-8068.