Composer Terry Riley, who came to fame nearly 25 years ago with a repetitious, droning, yet subtly changing piece called simply In C, has come to accept his place, for better or worse, as the founder of the minimalist movement, which later spawned composers such as Philip Glass and Steve Reich. Riley's more recent music, however, such as his 36-minute Crow's Rosary, which he premiered here in a rare appearance with the Kronos Quartet last spring, has been strongly influenced by his intense study of Indian vocal music. Chicagoans will have a chance to hear the first complete concert of music by Terry Riley in almost a decade on Saturday, when Riley teams up with soprano saxophonist George Brooks for a concert sponsored by Southend Musicworks. Some of the music on that program will reflect Riley's recent experiments with new ways of organizing pitches, but much of Saturdays program will be devoted to works from the early 80s, written or arranged for piano and saxophone, spotlighting Riley's jazz-influenced pieces, especially those heavy on improvisation. Saturday, 8:30 PM, Southend Musicworks, 224 N. Desplaines; 283-0531.