For the past few years, Jim Sivard, a local reed player and percussionist, has been championing new music, and the improviser's art in particular. Last year he presented a Composers and Improvisers Festival, and he's had a regular series at the Eighteenth Street Studio. On Thursday he'll kick off a N.Y. Improvisers Festival at the Ritz installation on F Street; it moves to the studio for Friday and Saturday performances.

Among those joining Sivard are guitarist Elliot Sharp ("I've worked with him on a regular basis"); percussionist Charles K. Noyes ("he puts on quite a theatrical show"); trumpet player Lesli Dalaba ("like Elliot and me, she's a graduate of Bard College and just returned from touring in Europe with guitarists Fred Frith and Derek Bailey"). The fifth participant is Christian Marclay, a turntable artist who sometimes breaks records, pieces different ones back together and then plays them on a special turntable.

Although it's billed as an Improvisers Festival, Sivard points out that "there's really no such thing as total improvisation. If you've been playing like that for years and years, an order is obviously going to assert itself. They call it 'improvisation' because there's no formal song structure or chord progressions or recognizable melodies that you can walk away whistling, but we're working with definite tools that we've developed over the years."

The Eighteenth Street Studio belongs to dancer/choreographer Jan Taylor. Sivard rents it once or twice a month for concerts. "There's no one else in town who's interested in promoting this kind of music. I do all the publicity, make the calls, set up the performers and everything. It's quite rewarding for me, even though I lose bread. I'll be on top one of these days."