Formed in 1986 during the second wave of American klezmer revivalism, New York's Klezmatics are no purists: they'll hybridize the sound of the shtetl with rock, vintage jazz, cabaret, or any other style that suits their fancy. They reach an expansive new plateau on their most recent release, Rise Up! Shteyt Oyf! (Rounder, 2003), which is a resilient response to 9/11. The centerpiece of the album is a surprising cover of folkie Holly Near's "I Ain't Afraid," a song that affirms the value of faith while condemning fundamentalist violence--"I ain't afraid of your praying," sings Lorin Sklamberg in the gospel-tinged chorus, "I'm afraid of what you do in the name of your god." The band's varied arrangements call on a deep support cast to lend idiosyncratic accents to tragic ballads and ebullient stompers alike. Guest keyboardist Myra Melford adds Middle Eastern-sounding harmonium drones to "Yo Riboyn Olam," while "Kats un Moyz" is driven by Cuban son montuno patterns contributed by guest pianist Steve Sandberg. But the group is at its best playing uncut klez, whether racing madly through the Sklamberg original "St. John's Nign" or covering Shmerke Kaczerginsky's labor anthem "Barikada" (which they embellish with samples of a 1948 archival recording by the composer). While reedist Matt Darriau, trumpeter Frank London, and violinist Lisa Gutkin (a newcomer) are all high-flying soloists, their virtuosity never conflicts with the group's tight ensemble sound. Neil Sedaka--yes, really--headlines. $30. Wednesday, August 11, 8 PM, Pavilion, Ravinia Festival, Green Bay and Lake Cook Rds., Highland Park; 847-266-5100.