Arrays of widely spaced mono-directional loudspeakers (P.A.-style stereo configurations or "outside-in" surround-sound systems) have long provided the dominant paradigms for electronic sound diffusion. So prevalent are these models that alternatives have largely been ignored and electronic sound, regardless of musical aesthetic, has come to be inseparably associated with single-channel speakers (often in relatively high-volume contexts), or headphones. We recognize the value of these familiar paradigms, but believe that electronic sound can and should have many alternative, idiosyncratic voices. Through the design and construction of unique sound diffusion structures, we can reinvent the nature of electronic sound; when allied with new sensor technologies, these structures offer alternative modes of interaction with techniques of sonic computation

This paper (to be presented at the 2000 International Computer Music Conference in Berlin) describes several recent applications of spherical speakers (multi-channel, outward-radiating geodesic speaker arrays) and Sensor-Speaker-Arrays (SenSAs: combinations of various sensor devices with outward-radiating multi-channel speaker arrays). Spherical speakers have long been applied in the study the acoustic qualities of performance spaces. More recently, building on previous studies of the directional radiative properties of acoustic instruments (the NBody Project), they have been used in performance to reproduce some of the diffusion characteristics of conventional acoustic instruments; spherical speakers engage the reverberant qualities of their performance spaces and allow electronic and acoustic instruments to blend readily.

After custom-building several spherical speakers by hand, we began working with the U.S. Enclosure Company to produce over a dozen spherical speakers of varying sizes ranging from 8-inch to 14-inch (the quality of U.S. Enclosure speakers became unacceptably poor, but now these are available handmade, and beautiful, here). We will detail their use in the performance and recording of two works by composer Steven Mackey: a concerto combining electric guitar and digital signal processing with full orchestra, and a composition for string quartet and live-electronics/electric guitar. The electronic improvisation ensemble "interface" has integrated a family of these spherical speakers into their standard set-up, completely replacing their previous P.A. diffusion model; as we discuss, this has encouraged us to substantially reinvent our approach to the performance of live interactive computer-music.

This presentation introduces a large new 22-inch diameter SenSA (Bubba) motivated by the first SenSA, the Bowed-Sensor-Speaker-Array (BoSSA). The two SenSAs have been used together in performance to realize a new approach to electronic chamber-music. BoSSA has also motivated several new works for interactive dance performance systems and SenSA. Finally, we are exploring the use of spherical speakers and SenSAs in installation art, using the directional capabilities to create more compelling sonic experiences in open and closed spaces. We describe the design and construction of these systems, and, more generally, the new "voices" they give to electronic sound.

Dan Trueman, Curtis Bahn and Perry Cook

NEWS: you can now get beautifully handmade hemispherical speakers (which can be combined to make spheres); visit this site to learn more. These speakers are being widely used now, with orchestra, electronic ensembles, and others. Oddnoise has more info about users. I have used them with chamber ensembles, and recently to amplify the Hardanger fiddle in a work for Hardanger fiddle and orchestra.