Formed a couple years ago by cellist and composer William Raynovich, the Maverick Ensemble scored last summer with a festival here and in Urbana highlighting the music of avant-gardist Christian Wolff. Two of the three Chicago concerts in this year's edition--there will be four more downstate--focus on electronic-music pioneer James Tenney. In the early 60s Tenney worked a day job at Bell Labs, devising computer programs for synthesizing sounds, and his pieces from that period are fascinating experiments with tone, noise, pitch, and statistical processes, reflecting the influence of Varese and Cage. But Tenney has also written harmonically anchored music, even ragtime; he's done politically driven pieces as well as works generated by mathematical rules. Perhaps because he's so hard to pin down, he hasn't earned much renown--but his music might prove just as durable as that of his more famous contemporaries (such as Steve Reich), not least due to his longtime partnership with filmmaker Stan Brakhage, which began when Tenney, at age 18, wrote a piano score to Brakhage's first film, Interim (1952). The Maverick's Bradley Haag will accompany this short in a program at the Gene Siskel Film Center this Sunday, which also includes a screening of Brakhage's Christ Mass Sex Dance set to Tenney's "Blue Suede" (yes, a riff on Elvis) and performances of "Three Rags" and a couple other miniatures. The Maverick's big Tenney retrospective, however, is Thursday, July 10, at the Renaissance Society; he has four pieces on the program, and his Voices Two is getting its U.S. premiere. The festival's local portion will conclude Monday at the Ukrainian Institute of Modern Art with a recital of Cage's sprawling Sonatas and Interludes for Prepared Piano and Three Monodies by former U. of I. professor William Brooks (which uses the same prepared-keyboard configuration as the Cage). The pianist for both will be English Cage expert Nicky Losseff. Thursday, July 10, 8 PM, Renaissance Society, Cobb Hall, University of Chicago, 5811 S. Ellis; 773-702-8670. Sunday, July 13, 7:30 PM, Gene Siskel Film Center, 164 N. State; 312-846-2800. Monday, July 14, 8 PM, Ukrainian Institute of Modern Art, 2320 W. Chicago; 773-227-5522.