IN A CONCRETE SPACE. RECONSTRUCTING THE SPATIALIZATION OF IANNIS XENAKIS’ CONCRET PH ON A MULTICHANNEL SETUP Andrea Valle CIRMA - Universit` a di Torino andrea.valle@unito.it Kees Tazelaar Institute of Sonology - Royal Conservatory The Netherlands info@keestazelaar.com Vincenzo Lombardo CIRMA - Universit` a di Torino vincenzo@di.unito.it ABSTRACT Even if lasting less than three minutes, Iannis Xenakis’ Concret PH is one of the most influential works in the electroacoustic domain. It was originally created to be dif- fused in the Philips Pavilion, designed by the same Xenakis for the 1958 World Fair in Brussels. As the Pavilion was dismantled in 1959, the original spatialization design de- vised from the Pavilion has been lost. The paper presents new findings about the spatialization of Concret PH. It dis- cusses them in the light of Xenakis’ aesthetics, and con- sequently proposes a plausible reconstruction of the spa- tialization design. Finally, it proposes a real-time, inter- active implementation of the reconstructed spatialization, rendered on a 8-channel setup using a VBAP technique. 1. INTRODUCTION In 1956 Iannis Xenakis was working in the studio of Le Corbusier, when Philips company commissioned the fa- mous architect a pavilion for the 1958 World Fair in Brus- sels 1 . The fair, being the first after the II World War, was a crucial event for the company: in particular, Louis Kalff, artistic director of Philips, considered it an occasion not to be renounced in order to show the world the technolog- ical advancements of the Dutch company. Le Corbusier accepted the commission and replied by promising to real- ize not an exhibit structure but a revolutionary “electronic poem”. Le Corbusier’s conception strictly adhered to the modernistic assumption that sees in technology the way in which art can fulfill a palingenesis of humanity: the archi- tect proposed Philips a Wagnerian total artwork of sound and lights, taking place in a space explicitly designed as a container for the show. As a consequence, the project for the Philips Pavilion resulted in a complex work of art, the Po` eme ´ electronique: an 8-minute multimedia work in which architecture, image and sound were deeply inter- mingled. The show included a black and white film, made of two filmed sequences created from still images, various 1 This work extends the EU-funded VEP Project (http://edu.vrmmp.it/vep/), that has reconstructed the Philips Pavilion and the Po` eme ´ electronique using virtual reality techniques. For a presentation of the project, including previous works, see [1]. Copyright: c 2010 Andrea Valle et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License 3.0 Unported , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Figure 1. The Philips Pavilion. light effects over the whole space, and electronic music to be delivered onto a multichannel system. While keeping for himself the creation of the visual part of the show, Le Corbusier asked one of the most avantgardist composers of XX-th Century to join the project, Edgar Var` ese. In the occasion, Var` ese created, as a musical counterpart for the visual component, his Po` eme ´ electronique: originally a 3- track tape music, Var` ese’s Po` eme is one of the undisputed masterpiece of electronic music. At that time, Iannis Xe- nakis was an associate at Le Corbusier’s studio, where he had already developed some of his well-known architec- tural exploits (e.g. the monastery of La Tourette). Xenakis was responsible for the design of the space. Xenakis turned Le Corbusier’s original idea of a shell-like structure, based on a stomach-shaped plant, into a self-carrying, concrete shell, higher than 20 meters. More, the Pavilion’s shape was generated by Xenakis as rule-based surfaces, namely hyperbolic paraboloids: the resulting shape was a tridi- mensional architectural object made of continuous curved lines. By explicit admission of Xenakis, the ruled surfaces of the Pavilion (see Figure 1) bear a structural relation to the striking opus 1 of the composer/architect, Metastaseis (1953/54) [2]. In this work, Xenakis started from a theo- retical problem, that of defining a continuous transition be- tween two discrete states (Xenakis, cited in [3], also [4], p. 32). The solution was based on devising a system of string glissandos with different speeds and ranges (“sonic spaces of continuous evolution”, [5], p. 10). While designing the pavilion, his “inspiration was pin-pointed by the experi- ment with Metastaseis”, so that there is a “causal chain of ideas” connecting the two works. Thus, in the Philips