A side released on Ayler Records raises expectations associated with the namesake of the label that is a very high watermark in improvised music, indeed. Musicians must have very special mettle to dare climb such heights or tread such waters, whatever metaphor you might prefer. The trio of Louie Belogenis, Joe Morris and Charles Downs, on saxophones, double bass and drums, respectively, is more than up to the challenge, and they lay down some serious material here before a small but appreciative audience at John Zorn's NYC venue on April 24, 2009.

The trio is very aptly named, as "Flow" is one of the dominant impressions of this music that is in constant ebullition, evolution, devolution and everything in between. The first and longest piece at nearly half-an-hour, "Set Theory" is a slowly developing swirl of keening tenor sax, with throbbing ostinato bass figures and flighty drums morphing constantly. The textures change kaleidoscopically, and the process includes moments when one of the trio lays out and returns, and Belogenis switching mid-stream from the robust tenor to the sprightlier soprano.

The second piece in this live triptych, "Infin Trinity" evolves from simple bass cells into a vortex of pyrotechnical expostulation in a kind of spiral form, with each musician pursuing rich textural and motivic ideas, with extended bass and drum solos along the way.

A quiet intro sets the tone for the more subtle and introspective "The End of Certainty," in which Belogenis' soprano spills long streaks across the languorous tableau of Morris' huge bass sound and Downs' whimsical drum wash, bringing the music to an understated poetic and meditative mode of closure.