by Nate Chinen

SEM and Ostravska Banda perform Muhal Richard Abrams, George Lewis, & Roscoe Mitchell // The Trio (Abrams/Lewis/Mitchell)

“Reductio ad absurdum!” Thomas Buckner pronounced, in stentorian voice, at one point in “AACM50,” a momentous new-music concert on Wednesday night at the Bohemian National Hall. It was just one of many lines of text, most of them sung, in the premiere of “Kingmaker,” by Roscoe Mitchell. But the phrase — best known as a rhetorical device — bore sly implications for the piece, composed for baritone (Mr. Buckner), saxophone (Mr. Mitchell), orchestra and choir.
As the concert’s title implied, “AACM50” was part of a succession of events celebrating the 50th anniversary of the Association for the Advancement of Creative Musicians, an experimental collective formed in Chicago but also deeply rooted in New York. Presented by the Interpretations Series and the Czech Center New York, the program on Wednesday also featured works by Muhal Richard Abrams and George Lewis, winningly performed by the Orchestra of the S.E.M. Ensemble, with the conductor Petr Kotik.
The concert hall, a high-ceilinged ballroom, was full, with a high concentration of musicians in the audience. (Among them were the multireedist Henry Threadgill, who’d had a piece performed under similar circumstances on Tuesday night.) It’s far from common to hear works by these composers on this scale, which was one reason for the elevated sense of occasion in the room.
Mr. Lewis, a trombonist and electronic musician who has been the association’s chief scholar-historian, imbued his piece with an impressive breadth of texture and overtone. Titled “Memex,” commissioned and first performed by the BBC Scottish Symphony Orchestra last year, it’s a musical response to scientific theories of the mid-1940s that presaged the invention of hypertext.
The mood of the piece was ominous and unsettled, but also darkly alluring, with a use of glassy dissonance that registered as richly luxurious. Sometimes this boiled down to the precise application of extended techniques — twitchy tensions among the strings, a violin bow raked across the edge of a vibraphone bar — and sometimes it was more a matter of a massed sound tipping slowly forward, like a toppling iceberg.
Mr. Abrams, the pianist who laid the groundwork for the association in the early 1960s, employed more conventional orchestration in his composition “Mergertone,” aside from the electronic color-field shimmer that served as its prelude. There was answering banter between sections, and a traceable accumulation of layers. At one point, a solo French horn played a stark motif, joined in sequence by fluttering clarinets and a woodland stir of flutes and oboes, before the cellos brought in an anchoring line.
“Kingmaker” was, by design, the least formally coherent of the three pieces, and in some respects the most engaging. Mr. Mitchell, who has extensive history with Mr. Buckner, tailored the libretto to his strengths, framing it with rumbling fanfares, rustling abstraction and a kind of troubled romanticism.
The libretto featured puckish arrangements of word-sounds — as in “Skint ruck yare gamp phat cant” — worthy of language poetry. (Reductio ad absurdum, indeed.) But Mr. Buckner brought a deadpan gravitas to his delivery, as did a four-person choir.
There was less playfulness but more play in the second portion of the concert, a half-hour group improvisation by Mr. Abrams on piano, Mr. Lewis on trombone and Mr. Mitchell on soprano, alto and sopranino saxophones. Mr. Mitchell emerged as the focal point, with a trilling incantation that poured forth in a torrent, by way of circular breathing techniques. Mr. Lewis worked with terse melodic shapes and the occasional expressive indulgence, like a nubby, muttering tirade played with one palm covering his mute.
But the most striking thing about the performance was its secret logic of cohesion, the way in which three wild strands of atonal outpouring managed to form a compelling shape. This was a shared achievement, but Mr. Abrams seemed especially crucial. During one stretch, he sat with his hands folded in his lap while the others blustered; eventually he played one pristine, gleaming chord, and returned to watchful silence.