A pioneer of the electronic-music movement, Morton Subotnick has been accused of being a technologist without a soul, and entries on him in reference books emphasize his infatuation with gadgetry. In 1967 he made a big splash with Silver Apples of the Moon, the first of several commissions for Nonesuch Records, written with the aid of a modular synthesizer to create colorful tone clusters and unusual pitches. By 1977 he'd developed the "ghost" box, a device that depends on spurts of voltage to generate pitches with trailing tones; many compositions from this phase of his career pit live performers against electronic ghosts. In 1981 he turned to the mainframe computer to do further experiments with the interaction between man and machine; in his Ascent Into Air, for example, live performers, through sophisticated software, influence where a sound is placed and how it's modulated. The 60-year-old avant-gardist, who now teaches at the California Institute of the Arts, recently hit on another idea: a single performer guides and "conducts" computer instruments in interpreting music his own way. At this Ravinia showcase of his chamber pieces Subotnick will unveil Angel Concerto, a work in progress that involves a Yamaha Disclavier. Five Scenes From an Imaginary Ballet, based on a collage novel by Max Ernst, combines video images, words, and music. But these technical exercises are not likely to match the emotional impact of Jacob's Room, a minor masterpiece that actually bodes well for the future of electronic music. In this opera for two characters--a young man (sung here by Thomas Buckner on tape) and his mother/guide (the redoubtable soprano Joan LaBarbara)--the horror and pain of the Holocaust and the guilt felt by its survivors are conveyed with harrowing intensity. This account of alienation and spiritual acceptance will be accompanied by footage from various archives on a video monitor. Monday, 8 PM, Bennett Hall, Ravinia Festival, Green Bay and Lake Cook Rds., Highland Park; 728-4642.