“Playing It UNsafe” is how the American Composers Orchestra characterizes tonight’s concert of works by Henry Threadgill, Joan La Barbara, Sean Friar and Laura Schwendinger at Zankel Hall, NYC. Afraid of classical musicians improvising? Multi-layered “sound paintings” of multi-tracked voice, electronic ambiance and instrumentalists sitting in the audience? Symphonic and light collaborations? Then walk on the wild side — or at least watch the fine videos by Jeremy Robins — like the two of Threadgill explaining his ACO-sponsored research and development project, below —