By Anne Midgette
The New York Times 

Expanding Boundaries, Physical And Artistic

At first there was something a little self-conscious about the moment when the flute player and violinist began walking around the stage. This was, after all, a chamber concert at the Metropolitan Museum of Art, and in performance classical musicians tend to stay put. But Eighth Blackbird, a group of six young instrumentalists specializing in contemporary music, deliberately set out to explore the boundaries of a conventional recital on Friday night. And within a few minutes their roaming the stage seemed as natural as splitting the movements of four distinct pieces of music and combining them in continuous washes of sound.

You'd say the group jammed, especially in Roshanne Etezady's ''Eleventh Hour'' (actually the second movement of her piece ''Damaged Goods''), which closed the concert with frenetic energy. Except ''jammed'' doesn't quite cover it: for all of its experimentation, Eighth Blackbird retained a sense of the traditional proprieties. Its name comes from the Wallace Stevens poem ''Thirteen Ways of Looking at a Blackbird,'' the verse about ''noble accents/and lucid, inescapable rhythms,'' and the reference is telling: the ensemble's funkiness is firmly inscribed within intellectual, high-culture parameters. These players aren't rebels in the downtown spirit of Bang on a Can. Rather than breaking down the barriers between classical and pop, they seemed to be folding in pop influences to help expand the definition and scope of classical music -- on classical music's terms.

The Stevens poem also addresses questions of perception that were a central issue of Friday's concert: how is our understanding of a piece of music affected by the way we look at it? Four young composers who style themselves the Minimum Security Composers Collective wrote autonomous, four-movement pieces, generally thoughtful and lively, from Adam Silverman's ''In Another Man's Skin,'' a lyrical, romantic, almost conservative exegesis on the Beatles' ''Blackbird,'' to Ken Ueno's ''Pharmakon,'' with three very brief ''pre-movements'' leading up to a longer main event.

On Friday the boundaries of those pieces and the composers' intentions were deliberately ignored. The result was a kind of performance piece, an engaging experience that ended up reaffirming the traditional definitions it seemed to be trying to challenge.