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One of the marquee events at this year’s Sonic Circuits Festival is the David Behrman Ensemble‘s performance Friday of “My Dear Siegfried,” a piece inspired by correspondence between Siegfried Sassoon (one of Britain’s famed World War I poets) and Behrman’s father, S.N. Behrman (a playwright and New Yorker writer). Like so much of the music at Sonic Circuits, it’s a work that never comes out the same way twice; in the video above, Behrman says D.C. audiences will be getting the latest version, which the ensemble also performed last week in New York. (Here’s a clip from a performance in early 2012.)

In explaining the composition (which includes sounds shaped live by Maximus music software), Behrman also happens to describe a significant part of the Sonic Circuits ethos: “It’s rather loose, and somewhat unpredictable, so that means that some performances are better than others, because it depends on … what’s in everybody’s mind … but I prefer that to more strict music, where these performers might be reading phrases.”

The ensemble features vocalists Eric Barsness and Thomas Buckner, cellist Ted Mook, shakuhachi player Ralph Samuelson and trombonist Peter Zummo.

The David Behrman Ensemble performs “My Dear Siegfried” on Friday at 7 p.m. at the Atlas Performing Arts Center. The festival runs Sept. 28 to Sept. 30.