Barry Truax Riverrun (1986/2004), a case study from the TaCEM project, exploring new approaches to techniques of analysis and re-synthesis in the study of concert electroacoustic works

At last year’s EMS in Lisbon we introduced the TaCEM project (Technology and Creativity in Electroacoustic Music), a 30-month project funded by the UK’s Arts and Humanities Research Council, and demonstrated the generic TIAALS software being produced as part of this project. This year we present an update on the project, focusing particularly on the first of our case studies, Barry Truax’s Riverrun.
Eight works have been selected for the project, taking into account criteria such as historical context, the nature of the synthesis techniques employed, and the aesthetics that have underpinned their realisation. Key considerations have included the accessibility of the technical resources and composing materials used in their production, and opportunities to pursue particular lines of enquiry with the composer concerned. In selecting the eight works for detailed study, a further consideration has been the extent to which the composers explored techniques that were already available at the time in ways that are unique and distinctive, or alternatively developed entirely new methods of synthesis in pursuit of their creative goals. The pioneering work of Barry Truax in terms of developing techniques of granular synthesis assign his achievements almost exclusively to the latter classification, and the composition of Riverrun (1986/2004) is a landmark achievement in this regard.
Truax’s composing environment evolved from the early study of interactive real-time synthesis techniques at the Institute of Sonology, Utrecht 1971-73, exploring the possibilities of using Poisson-ordered distributions in the generation of microsound, to the emergence of entirely granular techniques at Simon Fraser University, British Columbia a decade later, culminating in the development of his program GSX designed specifically for waveform-based synthesis and first used to compose Riverrun, and its later extension, GSAMX, that extended these granular techniques to include the manipulation of previously sampled sound material.
At the time of composition conventional minicomputers still lacked the capacity to generate multiple voices of granulated sound material in real time, but for Truax the acquisition in 1982 of a high speed bit slice array processor, the DMX-1000, provided the enhancedprocessing power necessary for achieving such a goal. The unique characteristics of its special hardware and associated programming environment, managed in turn via a host PDP 11/23 computer, both empowered his creative objectives and also materially shaped and influenced the ways in which they could be practically achieved. The significance of such causal relationships in the evolution of the electroacoustic music repertory has yet to be widely understood, and this study of Riverrun corroborates the importance of such a line of investigation. In this case it has been possible to carry out a detailed study of the original system, still maintained in working order by Truax, leading to a reconstruction of key elements of Riverrun using a Max-based simulation of GSX, the authenticity of the results being assessed both subjectively by means of a direct aural comparison and also measured objectively using software.
Our presentation at this year’s EMS in Berlin included a demonstration of examples of the software we have developed to enable readers to engage with Riverrun interactively, both by analysing the original recordings and by using our emulation of the GSX system to be able to recreate passages of the work and manipulate the techniques employed in order to learn more about them. We also gave examples of other materials we have collected in relation to this case study, including videos of the composer himself working with the GSX system and discussing the composition of Riverrun.