Six years into its history, the annual Sonic Circuits Festival of Experimental Music has become more than just a curious happening—it’s an institution, at least among those who appreciate the outer reaches of human-made sound. It doesn’t hurt, of course, that D.C. itself has become a hotbed for experimental composers and out-there electronic music. The four-day event has some noteworthy headliners this year—including drone-music and “intermedia” legend Phil Niblock, Hawkwind noisemaster Harvey Bainbridge, and Sub Pop weirdos Wolf Eyes—as well as a healthy handful of European acts. But the organizers have made plenty of room for local mainstays such as the Caution Curves (pictured), Mikroknytes, and Jeff Bagato (performing as Tone Ghosting). Whether they use traditional instruments, found objects, or odd electronic gear, the performers all have one thing in common, says Jon Morris, one of the festival’s organizers: Their work defies categorization, born of everything from academic study to “post-classical” sounds to the fringes of rock and jazz. “The phrase ‘cutting edge’ may not mean much these days,” Morris says, “but I think we’ve assembled a group of artists who truly are out there on the edge.” Jeff Surak, a festival organizer and longtime musical experimenter who runs Zeromoon Records and performs solo as Violet, simply calls it “a celebration of audio extremes.” Tonight’s performance begins at 8:30 p.m. at the Warehouse Next Door, 1017 7th St. NW. $12 . (202) 783-3933. The festival runs through Sunday, Oct. 8; see for a complete schedule. (Joe Warminsky)