DISSCO tech: Advancing the legacy of computer music at Illinois

by Katherine Kendig

Music is universal, but computing music—that is, composing pieces via computation rather than human input alone—is kind of an Illinois thing. Sever Tipei, a Professor of Composition-Theory at the University of Illinois at Urbana-Champaign, says the connection began in 1956 when Lejaren Hiller created the first major piece of music composed by a computer, the Illiac Suite. At a time when the computer keyboard was still an experimental novelty, Hiller used Illinois’ Illiac I—”one of the most powerful computers of the time”—to bring together computation and artistic creation. The Experimental Music Studios he created at Illinois two years later is still in existence today.

In the twenty-first century, Tipei, who is also a National Center for Supercomputing Applications (NCSA) Culture and Society Faculty Affiliate, has been the central figure carrying on Hiller’s legacy. In 2005, he and mathematician Hans Kaper (of the DOE’s Argonne National Laboratory) created DISSCO, a Digital Instrument for Sound Synthesis and Composition. As its name suggests, DISSCO doesn’t just allow users to compose music; it also enables them to digitally create the sounds that will comprise each piece. Unlike an electronic instrument with a variety of pre-programmed sound options, DISSCO users build sounds algorithmically—and completely from scratch.

DISSCO, Tipei says, is “an ongoing project.” The aesthetics and functionality of the program have both improved since the beginning, with user-friendly updates like a custom DISSCO interface to replace the original command-line operation. Now, Tipei is marshalling outside resources to keep driving DISSCO forward: to implement new features, he’s working with Yuyuan Chen and Shenyi Wang, student interns in NCSA’s SPIN program. And to improve DISSCO’s computational speed, he’s enlisted the computing and consulting resources of the Extreme Science and Engineering Development Environment (XSEDE).

Tipei says Alan Craig, a member of XSEDE’s Extended Collaborative Support Services (ECSS) team, was extremely helpful in pushing the collaboration forward: “Alan has been instrumental. I didn’t know about XSEDE—he introduced me to it.” Craig specializes in helping researchers from the arts, social sciences, and humanities advance their projects using XSEDE resources. To enhance DISSCO, ECSS consultants Paul Rodriguez and Bob Sinkovits worked on the Comet supercomputer at the San Diego Supercomputer Center to implement parallel processing and reduce the compute time for sound synthesis. Heading into the collaboration with XSEDE, a twelve-minute piece of music could take DISSCO fifty minutes to compute because for each second of sound, Tipei says, 44,100 samples representing frequency, volume, depth, location, and other “shades of gray” must be processed. Rodriguez and Sinkovits achieved a 70% reduction in computing time by implementing the Message Passing Interface for parallel architectures on top of existing code—meaning that same twelve-minute piece could now be computed in as little as fifteen minutes. Tipei says Craig provided consistent communication, cooperation, and support as Rodriguez and Sinkovits optimized DISSCO’s code.

At the University of Illinois, students can get their own taste of DISSCO through classes like Introduction to Computer Music—no experience in computing or music required. Tipei, who teaches the course, says he starts with the history of the field, then teaches the necessary programming, and finally lets students loose to compose and synthesize their own pieces. The final products are inherently unpredictable: As with science, Tipei says, students “set up an experiment, but might be surprised by what comes out.” The possibilities for each created sound are nearly unlimited, which fits with the music department’s focus on encouraging experimentation, originality, and coming to terms with uncertainty.

Tipei himself actively employs uncertainty in his music, using DISSCO as a tool to break away from narrativity. “No matter what you do, there is going to be some cohesion—each piece has its own coherence. But,” he adds, “not necessarily a story.” By working against expectation, Tipei forces listeners to actively synthesize what they’re hearing, instead of accepting something that feels ready-made. “It’s a step farther than jazz,” he says.

DISSCO isn’t just for musicians—Tipei notes the program can also be a powerful tool for sonification. “DISSCO can handle more than a dozen degrees of freedom in the definition of a single sound,” Tipei says, so data—particularly complex computations—can be distinctly rendered, giving researchers an auditory supplement or alternative to traditional visualization. Collaboration with scientists studying Graph Theory and Information Theory could even create a pathway for DISSCO to contribute to the study of artificial life: “Determining the evolution of a musical object in continuous transformation, an Evolving Entity… could trigger new ideas” in the field, Tipei suggests.

As DISSCO continues to evolve, building on the 60+ years of computer music innovation at Illinois, Tipei acknowledges that the landscape of computer music has changed. While commercial sound synthesis software is available, however, Tipei says other programs lack the continuity DISSCO provides by fusing composition and sound synthesis in one environment. “I don’t mean to brag,” he adds, but in comparison with alternatives, “students say DISSCO has better sounds.” Ultimately, Tipei concludes, “DISSCO is different.”

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