It took two decades for reedist Jeff Newell to finally release an album by New-Trad Octet, the inventive band he assembled to revisit trad-jazz classics and recast mainstream jazz tunes with a New Orleans marching band sensibility. But anyone expecting to hear the group tackle Armstrong, Ellington, Mingus, and Parker on the just-released Brownstone (Blujazz) is in for a surprise--Newell and his merry misfits don't cover any jazz at all. They adhere to the New Orleans sound, but the material is much older: three Sousa marches and a six-part suite called Hymn Pan Alley, the movements of which are based on melodies by little-known early-20th-century composers from Newell's adopted neighborhood of Fort Greene, Brooklyn. With the suite, Newell proves himself to be as much a musical archaeologist and iconoclastic composer as he is an innovative arranger, neatly and effectively combining two contemporaneous bygone idioms without resorting to campy high jinks or tongue-in-cheek send-ups. His onstage band will include Orbert Davis on trumpet, John McLean on guitar, and Steve Million on organ. In addition to his two-night Green Mill gig with the octet (see also Saturday), Newell will play a free trio show at 12:15 PM today in the Randolph Cafe of the Chicago Cultural Center, 78 E. Washington; call 312-744-6630 for more info. a 9 PM, Green Mill, 4802 N. Broadway, 773-878-5552, $12.