The musicians were using an IRCAM-written artificial intelligence software program called OMax designed to learn in real-time the typical features of a musician's style and then use those lessons to alter the musical output, giving the flavor of a machine collaborating with a musician to yield a novel improvisation. OMax, produced by IRCAM's Musical Representations Team, achieves this in part by creating a digital "clone" of each musician that interacts with the musician's output as well as other musicians' clones during a performance.
"The bows were actually controlling not only our own sound processing but the processing of the other person," Kimura says. "I could change Dave's processing with the bow, and he changed my processing with his."
The computer acts almost as a composer, but it's not exactly a third instrument. The output originates only from the duo. As a result of the computer's influence, however, "you're not really in control of the music," Eggar says. "Jazz improvisation is actually more predictable. When I do something, I can pretty much tell what someone else will do. Tonight's performance was very different."
Computers and music have become intertwined over the past several decades, says Eggar, himself a Grammy-nominated experimentalist who has performed with musicians running the gamut from Hannah Montana to the Philippines's indigenous Talaandig tribe. "Mari's really owning that and defining what it means for a musician to interface with a computer," he adds.
Technology aside, a striking component of Kimura's performance is the integration of her subharmonic bowing techniques that she has been developing for nearly two decades. The objective behind subharmonics is to extend the violin's range by a full octave. For example, she can hit notes below the not fingered "open" G string—normally the lowest note in standard tuning—into the cello range without altering the instrument's tuning. Throughout her performance Kimura's bow flew across the strings as she delved into the subharmonic range and back, often during a single bow stroke.
A likely next step for Kimura is to use the technology behind the augmented violin to better understand subharmonics. The late Yale University physicist William Bennett—co-inventor of the first gas laser—dedicated a considerable amount of time prior to his 2008 death studying some of Kimura's techniques, writing in his 2006 book The Science of Musical Sound about what he termed "subtones" produced by her violin. Still, he was not able to pin down precisely what mechanism she used to produce, as he put it, "octave subtones."
Kimura estimates that within a year or two she would like to work with IRCAM to better understand how subharmonics are produced. "Right now, all I have is my kinetic memory and a voodoo feeling that's, like, I can do it, I can do it," she says. "It would be great if there were some sort of data that says this is how much pressure and speed, a quantifier of some sort."
Kimura is leery of her reputation for experimentation superceding her skill as a violinist. "I hope you will see an everyday violinist, except that a computer participates in my performance," she says. Somehow, it is unlikely that her audiences will ever see her performances as commonplace.