Like fellow avant-gardist John Cage, Lou Harrison has turned a lifelong infatuation with Oriental music--especially the Javanese branch--into a rich and varied body of fascinating, Eastern-accented sound assemblages. Incorporating a wide variety of influences and techniques ranging from his mentors Henry Cowell and Schoenberg to Chinese shadow-play music, Harrison's music can be mesmerizing: waves of enchanting melodies that ebb and flow in sharp, exotic rhythms. Much of what this west-coast iconoclast and theorist composes reflects his concerns with "love, plant growth, peace, and concerted enjoyment on the journey to death." Another facet of his lengthy career is the constant bold experimentation with instruments, particularly those in the resonant, multitextured Indonesian orchestra called the gamelan. For his Ravinia debut, Harrison has chosen an intriguing sampler of music for the gamelan, both original and traditional. Of note are: Gending in Honor of Aphrodite (Greco-Roman themes told through a compositional form having two balancing sections, each repeated at least once) and Bubaran Robert (based on a Javanese convention designed to send the audience merrily on their way with the sounds of gamelan still ringing in their ears). Also on the program is the decidedly Western (and intricate) Grand Duo for Violin and Piano (to be performed by Romuald Tecco and Dennis Russell Davies, to whom the work is dedicated). The concert's centerpiece must be the Gamelan Si Betty, built and tuned (to a just intonation) by Harrison and collaborator William Colvig; it is reportedly an awesome sound machine and a sight to behold. Monday, 8 PM, Murray Theatre, Ravinia Festival, Green Bay and Lake Cook Rds., Highland Park; 728-4642.