In the 1970s and '80s many Bulgarian musicians lived in fear of serving prison time: as part of a depressing communist-era attempt to foster national unity, ethnic music, particularly Turkish and Gypsy, was strictly forbidden. Weddings, because they were private, became the underground venue of choice, but clarinetist Ivo Papasov and saxophonist Yuri Yunakov, the two lead members of the group playing tonight, both served brief jail terms when they played together in a band called Trakiya. Though crackdowns on so-called wedding bands continued even after the 1989 revolution, the fall of communism helped the pair find a wider audience, and their music on two out-of-print early-90s albums billed to Papasov, Orpheus Ascending and Balkanology, is breathtaking in its originality, complexity, and speed. Over dizzying meters like 7/16 and 9/8, the musicians zoom through elaborate, zigzagging traditional melodies steeped in rich harmonies. The technical rigor of their playing is in a league with even the most ferocious work of Charlie Parker and Dizzy Gillespie, but no matter how wild the improvisations get, the music's rooted in funky, danceable grooves. Tired of the oppressive environment in Bulgaria, Yunakov relocated to New York in 1994 and formed his own group, which has released three terrific albums, and he reunited with Papasov in the fall of 2003 to record the new Together Again: Legends of Bulgarian Wedding Music (Traditional Crossroads). Driven by the orchestral accordion playing of Neshko Neshev and the hyperactive beats of drummer Salif Ali (both also former members of Trakiya), the two reedists sound as acrobatic as ever; their tonally sharp playing flies by with such fury it's easy to miss how melodically inventive they are. The four musicians on the album will play at this show, billed as Bulgarian Bebop. Fri 11/11, 7 and 10 PM, Old Town School of Folk Music, 4544 N. Lincoln, 773-728-6000 or 866-468-3401, $20, $16 seniors and kids. All ages.