It’s Alive! It’s With the Band! A Computer Soloist Holds Its Own

Two guest soloists, each skilled in the art of improvisation, appeared in New York City on Friday night with the cutting-edge chamber group Ensemble Signal.

One soloist was human: Nicole Mitchell, the veteran flutist, composer and bandleader whose albums and performances are regularly (and rightly) celebrated by jazz critics.

The other soloist was a computer program — called Voyager — that can listen to live performances in real time and offer improvised responses. Originally programmed in 1987 by George Lewis, the composer, performer and computer-music pioneer, Voyager’s discography is slighter than Mitchell’s, but likewise thrilling.

On a 1993 CD for the Avant label, Voyager played the role of a real-time improvising orchestra — alongside Lewis’s trombone and the saxophone of Roscoe Mitchell (no relation to Nicole Mitchell). By the time of the 2019 RogueArt album “Voyage and Homecoming,” Voyager had been updated to perform — next to those same soloists — on a computer-controlled Disklavier piano. This, in turn, has made it possible for Voyager to enter into the tradition of the distinctive soloist, partnering with orchestras or chamber groups like Signal.

On Friday at the DiMenna Center for Classical Music in Hell’s Kitchen, Voyager improvised on a concert grand Yamaha Disklavier, sharing the stage with Nicole Mitchell and members of Signal. These forces united to give the U.S. premiere of Lewis’s “Tales of the Traveller,” the final composition on a program presented as part of this year’s Time:Spans festival, which runs through Saturday.

Lewis’s material for Signal is fully notated. But his score gives an improviser no notes to play — nor does it specify the instrumentation or number of improvising soloists. (The composer offers only entry and exit points for soloists.) Lewis merely gives soloists some advice regarding what not to do, when entering the fray. “Direct imitation of melodic or harmonic passages is to be avoided,” he says, referring to what the chamber group is playing. So what should the improvisers do? “Strategies for dialogue with the written music include blending, opposition or contrast, and transformation.”

Without question, this was a lot of to-do for a 20-minute-plus performance at the end of a single show. But as “Traveller” unfolded, it proved a highlight of the year’s concert calendar, thus far, in New York.

In large measure, this was because of Lewis’s instrumental writing for the chamber group. You could take Voyager out, and “Traveller” would still sound vivacious — full of high-stakes drama and responsive good humor. (The 2016 world premiere performance of the work by the London Sinfonietta involved only a single human improviser.)

Lewis has been on a particularly strong chamber music run in the last 10 or so years. This hot streak has included larger-group efforts like “The Will to Adorn” and “As We May Feel” — as well as more intimate pieces like the “The Mangle of Practice.”

In these works, and in “Traveller,” you are often immersed in instrumental density — quick rhythmic accelerations and parched sound-production textures. But paradoxically, these moments rarely feel abrasive (as in some other forms of modernism).

Even when the music whips up complex, noisy nimbuses of competing motifs, the fast, finely judged changes within the dense activity are preparing you for variations on the weather. And, soon enough, there’s a clearing of skies: The music decelerates and makes room for melodic fragments that are voiced more sweetly. From there, you’re taken to the in-between states, with varieties of gradation. You get the sense that the suggestions Lewis lays down for his improvisers in “Traveller” — de-emphasizing imitation, and promoting contrast and transformation — are similar to the directives he charges himself with when composing.

On Friday, the Disklavier piano was turned toward the audience, allowing viewers to watch for the moments when the Voyager software — running on a nearby computer — elected to depress the keys of the Disklavier.

“It’s alive!” I thought — with a monster-movie watcher’s delight — when the piano first started playing, quietly. But since “Traveller” also has a part for a human pianist within the chamber group, you had to pay close sonic and visual attention to discern which pianistic choices were Voyager’s.

For all that techno-drama, it wound up being Mitchell who took the early, demonstrative lead in improvising — with some fluid, songful passages that added a depth of lyricism to the boisterous material for Signal. During this stretch, Voyager limited its contributions to fluttering, high register filigree. And it sometimes chose silence.

But since improvisation is also about knowing when to listen, that was no mark against the software’s intelligence. And when Voyager decided to make a forceful, fortissimo statement, late in the piece — in a relatively quiet passage for the chamber players — the provocation felt right on time. During the applause, as the conductor Brad Lubman made a gestures to both soloists, there was some laughter when he encouraged an ovation for Voyager. But the computer program had earned its plaudits.

This was the kind of performance that you want to hear in a residence, night after night. The improvisations would be different. And the notated music would be great to hear multiple times. But that’s not the world we live in. So while Lewis’s duos for live players and electronic partners are performed with some frequency, the star-soloist turns for Voyager — in the company of many human partners — are more rare.

Time:Spans is to be commended for producing the concert, even for a single night. This festival — put on each August by the Earle Brown Music Foundation — specializes in filling just this kind of contemporary-music niche. In past years, Time:Spans was where you could find important local premieres by John Luther Adams or works by comparatively lesser-known members of the Wandelweiser school. And it’s the rare festival at which you’ll also find members of Freiberg, Germany’s SWR Experimentalstudio.

In addition to Signal’s hugely entertaining take on Lewis’s “Traveller,” Time:Spans has already presented several other rewarding concerts this year. In a single week I enjoyed gigs by the quintet Splinter Reeds, the Argento New Music Project chamber ensemble and the International Contemporary Ensemble, known as ICE.

ICE’s set on Saturday had many points of connection with the Signal show — in part because of the presence of three other works by Lewis. Enjoyable as those were, the brightest moment of that concert was a contribution from the pen of Mitchell, “Cult of Electromagnetic Connectivity.” (This concert was entirely for human players.)

Written for the cello, violin, flute, a percussionist and a clarinetist (who doubled on bass clarinet), the 10-minute piece was often powered by a succession of duos within the quintet; these vivid episodes were often connected by gloomy but propulsive motifs played by the percussionist Levy Lorenzo.

This week brings sets by the JACK Quartet, Yarn/Wire and the Talea Ensemble. Tickets are affordable; the acoustics grand. It’s a reason to hang around town in the depths of summer swelter.