Saxophonist Jemeel Moondoc and bassist William Parker have both said that when they played together in Ensemble Muntu over two decades ago, the band summoned the spirits of jazz demigods like Coltrane to their rehearsals--and that at one transcendent gig they actually levitated off the bandstand. I don't know if any ghosts were in attendance when the two men reunited for a duet at the Fire in the Valley festival in Amherst, Massachusetts, in 1998--the first time they'd shared a stage in over 12 years--but when I listen to the CD of that concert, New World Pygmies (Eremite), the way Moondoc's pungent, conversational alto twines around Parker's seething double bass never fails to raise my spirits. Over the past few years Parker has offered Chicagoans plenty of evidence, in splendid performances with Peter Brötzmann, Matthew Shipp, David S. Ware, and Roy Campbell, that there simply isn't a more passionate and exciting bassist playing jazz today. The 49-year-old Moondoc, on the other hand, is a relative unknown: his fortunes have waxed and waned along with those of free jazz itself, and though he was born and raised in Chicago, this concert will be his debut here. After university studies with Ran Blake, Bill Dixon, and Cecil Taylor in the late 60s and early 70s, Moondoc settled in New York City, where he, Parker, and drummer Rashid Bakr founded Muntu, a group that would go on to tour Europe and release four critically acclaimed albums. In 1984 Moondoc assembled a big band, the Jus Grew Orchestra, which held down a series of weekly engagements on the Lower East Side but never recorded. It eventually fell victim to the neoconservative malaise that's still poisoning jazz today: Jus Grew was dropped from a regular gig in favor of a repertory band, and in the early 90s Moondoc, who could see the writing on the wall, went back to school and became an architect. Fortunately, he never entirely abandoned music--those are his blues-drenched incantations on Denis Charles's Captain of the Deep, recorded in 1991 at the Zuid-Nederlands jazz festival--and for the last five years the tiny Massachusetts label Eremite has labored mightily to reinvigorate his career. The label started its catalog with his first studio date in 11 years, the 1996 trio outing Tri-P-Let, and since then it's issued the Charles album and two fiery live recordings under Moondoc's name--a trio date and the duo with Parker. It also has a March 2000 concert by the reconstituted Jus Grew Orchestra in the can. Moondoc's at the top of his game on these records, combining his raw, astringent tone with a fluid lyricism. He'll be joined here by Parker and drummer Hamid Drake. Saturday, November 4, 9:30 PM, Velvet Lounge, 21281/2 S. Indiana; 312-791-9050.