dreamed of a future in which musicians would acquire the skills of mathematicians, engineers, and physicists and use their artistic intuitions to, as she puts it, “come up with something for music in our time.” The idea that science and art have something important to teach one another has been trotted out so often that it has become a truism, yet it often falls short of the truth. A would-be chaotic composer need only click on a particular effect, choose a spot on a color wheel to set how close or distant they want the new version to be to the original, and—like magic—the program generates a new audio version of any song. Some variations sound almost unaltered, while others are unrecognizably minced up. A Scott Joplin rag may jag off in unexpected ways. A Franz Liszt piece can evolve so many times that it may become hard to remember which is the original and which merely a computational riff. In effect, it’s using math to generate inspiration. Variation is at the heart of all kinds of creation, and she has invented a new way of generating it. Dabby sees herself following in a musical tradition that stretches from Bach to John Cage. But variation is far more pervasive than that, showing up in all kinds of art and in each of us—down to the slight tweaks in our DNA that make us all recognizably different, though identifiably human. Accordingly, some people are beginning to borrow Dabby’s ideas to generate chaotic variations beyond music. The principles of her work have now been used to create new dance “chaography,” computer-generated variations on rock climbing routes, and even a chaotic remix of Lewis Carroll’s “Alice’s Adventures in Wonderland.” The word “chaos” is often used in common parlance to mean things that are disordered. To mathematicians, chaos is behavior that appears random, but is actually the result of a system that is evolving according to set rules. The reason chaotic systems seem so unpredictable and random is that they are sensitive to slight changes in initial conditions, commonly referred to as the butterfly effect—the idea that something as small and unpredictable as a whisper of air movement from an insect flapping its wings could cause a thunderstorm halfway across the globe. Dabby became interested in something called the “strange attractor,” a mathematical entity that pulls trajectories back toward it, sort of like a whirlpool that draws in nearby currents. Those trajectories are similar, but differ depending on the initial conditions. It reminded her of the musical concept of theme and variation—think of the recurring motifs in jazz, or any number of classical pieces where the theme is played, then repeated and translated into something new. What if, Dabby wondered, it were possible to generate chaotic variations in music? For her graduate work, Dabby used chaotic trajectories as a kind of scaffold for music. She would generate a particular curve, then translate a melody onto the curve—meaning that as one moved along the curve, each spot would correspond to one note. She would then map the notes onto a “pitch axis,” a kind of musical yardstick divided not into inches or centimeters, but into notes—one spot is middle C, another A sharp. Then, to create variations, she would generate a new curve, and use the pitch axis to determine the new order of notes. The result would be a subtly changed piece of music, with little and big differences in each phrase. From the beginning, the technique generated music audio files—some of which Dabby learned to play on the piano. She wanted to show that it would work on all styles of music, so she applied it to a prelude by Bach and another by Gershwin. When she began to think about building a Web program open to anyone, she wanted to make it as open as possible—simply using music files that anyone might have on a computer to generate new music. Despite what you might expect, the results don’t sound like some new form of computerized robot music. Instead, the variations end up sounding familiar—each one resembling the original piece, but stippled with unexpected bits. One year, a student came to Bradley with an idea: He was a ballroom dancer and wondered if the technique could be used to generate new forms of choreography. The conversation sparked a project, and eventually the approach culminated in a program called Chaographer that uses a similar idea to Dabby’s, mapping an original dance sequence and then varying it, using animation and motion capture. The technique was demonstrated in a 2007 performance in Boston called “Con/cantation: chaotic variations.” These techniques are decidedly not automated creativity. They still require the ear or eye of a person to curate the movements or passages, culling good ideas and tossing the ones that don’t make sense. In dance, impossible transitions need to be somehow controlled for or eliminated. In musical variations, gaps sometimes show up in the variation that make little sense to the human ear. But diversity—the thing celebrated in culture, music, and biology—needs to come from somewhere, and the variation generator is like a brainstorming device that takes the lid off all the possibilities.
Posted on: Thu, 18 Jul 2013 04:45:13 +0000
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