There were supposedly over a thousand performances scheduled for the Make Music New York festival on June 21. A daunting prospect, but I knew which one I had to attend. Listening to Dutch composer Louis Andriessen's Hoketus on my stereo could never convey the full flavor of this spatially designed piece, so I headed to the New York Stock Exchange for a 1 PM show (also part of the ongoing River to River Festival) for which the Exchange was allowing half of the ten performers (the oddly named ensemble Yarn/Wire and friends) to play from its balconies, which the other five players faced on the sidewalk across the street.

This modernist classic's title comes from "hocket," the medieval technique it's based on: opposing groups don't play at the same time, instead alternating, but in combination creating an overall pattern. Just as the performance was about to start, it seemed that there would be an eleventh, improvising player: down the block, a worker was hammering on some scaffolding. I don't know whether he was dissuaded from continuing by the organizers or just naturally knocked off work because it was lunchtime, but Andriessen's score was not augmented after all.

Speaking of lunchtime, the "audience" for this was partly intentional and partly, so to speak, accidental: stock brokers and others in the biz standing outside the exchange eating lunch, smoking, etc. If people won't go to avant-garde music shows, bring it to them!

As soon as the performance kicked off, the location imprinted a special effect on it: not only was the spatial separation very clear and effective, it was emphasized by the way the notes reverbrated between the stone facades, reminiscent of the antiphonal music of Gabrieli written for Baroque cathedrals.

At the start of Hoketus, pitch information is minimal, just two notes -- it's all about rhythm and power. Instrumentation is two keyboardists, one flutist, one conga player, and one electric bassist on each side, but with no sustained notes (except at one specific and brief point) sounded like it was all tuned percussion. The texture was sparse at first; more beats accreted, and soon the music became denser, but the spatial separation keeps it from being solid. The pitches eventually shifted; still just two, but farther apart. Patterns phased and snapped into new perspectives kaleidoscopicalliy. Timbres varied, also gradually. I saw one person start rhythmically bobbing in place -- the steady, insistent beat was infectious, at least for the believers. There was definitely a section of the audience that came for this.

Andriessen dramatically expands the pitches to two pairs of dyads on each side and moves faster; the pitches didn't seem to be in equal-tempered tuning at that point. The rhythms then became much denser. By this point, most of the people on the stock exchange side had been driven away; we were down to true believers (or at least immediate converts) and pedestrians by the time Andriessen's score progressed to dense chords. They were rewarded with -- from my perspective, at least; I suspect someone in a different location might have heard it differently -- one keyboardist temporarily moved to the front of the sound with something like a melody, then sank back down into the sea of patterns. Soon, dramatically, there was a brief but, in context, shockingly extended pause on a single held low note, solo; it seemed to act as a pivot. Then a new pattern kicked in, and for a little while the piece seemed to reverse its development in a very condensed way until a rousing but abrupt climax ended the piece.

The audience, perhaps a couple hundred people, erupted into applause. Given the impressive degree of disciplined precision it took to pull off this stunning work, Yarn/Wire (who contributed both drummers and two keyboardists) and friends deserved every bit of it. - Steve Holtje

Mr. Holtje is a Brooklyn-based poet and composer whose newest project is setting James Joyce's Pomes Penyeach for singer and cello.