The Immersive Computer-controlled Audio Sound Theater: Experiments in multi-mode sound diffusion systems for electroacoustic music performance Stephen David Beck, Joseph Patrick, Brian Willkie, and Kenley Malveaux Laboratory for Creative Arts & Technologies, Center for Computation & Technology Louisiana State University sdbeck@lsu.edu, jpatrick@cct.lsu.edu, bwillk1@lsu.edu, kmalve1@lsu.edu Abstract Multi-channel sound diffusion has been an essential part of the electroacoustic music process from the very beginning of the genre. We see early experimentation in sound spa- tialization in Var` ese’s use of loudspeaker “paths” in Po´ eme ` Electronique, Stockhausen’s experiments in quad and cube- based speaker arrangements (Chadabe 1997), and Chown- ing’s computational approach to sound diffusion in works like Turenas (Roads and Strawn 1985). Experimentation in deployment and usage of audio loud- speakers is seen in the loudspeaker orchestras at Bourges (Clozier 2001), GRM and Birmingham (Harrison 1999), Richard Moore’s notion of loudspeakers as “windows” to the virtual world beyond (Moore 1989), and the development of standard configurations for multichannel audio in digital video (5.1, 6.1, 7.1, 10.2) (Stampfl and Dobler 2004). And the recent interest in Ambisonic recording technologies (Mal- ham and Myatt 1995) has furthered the aesthetic goal of an immersive audio environments that place the listener in an alternative sonic world – a “virtual world” created by com- posers and sound artists. The Immersive Computer-controlled Audio Sound The- ater (ICAST, pronounced “eye-cast”) is a project that ad- dresses the various needs of multiple performance modes through a computer-controlled loudspeaker environment that is malleable, adaptable and intuitive. The system also ex- plores new and novel metaphors for sound control using both conventional and unconventional interfaces. ICAST is a hardware and software solution, based on a client-server computer control system, commodity audio interface hardware, and high-quality audio amplifiers and loudspeakers. What we have learned from this research has applications that go well beyond concert hall performances, and include virtual reality environments, cinema, and video games. 1 Introduction Motivation for this project grew out of our experiences hosting the 2001 SEAMUS 1 National Conference, our work with the Electric LaTex 2 student conference and the multi- tude of concerts we produce annually. In preparation for these events, we found it difficult to accommodate the vari- ous modes of multichannel diffussion in electroacoustic per- formance requested by composers. During the 2001 SEAMUS conference, about a third of the composers requested a speaker array that utilized point- source location or surround-sound mixing techniques, a third of the composers requested an acousmatic-style speaker ar- ray, and a third expressed no preference. And although we created two performance venues, one with a surround-sound speaker array and one with an acousmatic speaker array, com- posers often did not take advantage of the diffusion paradigms available to them, either because they did not have enough time to practice, or they did not know what to do with the performance mode through which their piece was presented. In response to our experiences, we began designing a multi-mode diffusion system that would allow composers and diffusionists multiple methods for electroacoustic perfor- mance without reconfiguring the speaker array, mixing con- sole or patch bay. The system can handle presentations in surround sound modes, acousmatique modes, or using Am- bisonic sound fields. We have also been conceptualizing new control interfaces and diffusion metaphors that facilitate com- plex sound diffusion processes without using the “mixing console” paradigm. This paper will describe the rationale for this project, specifics about its implementation, and the results from our 1 Society for Electro-Acoustic Music in the United States 2 Electric LaTex is an annual collaboration between electroacoustic music programs at LSU, the University of Texas - Austin, the University of North Texas, and Rice University 649