Pierre Carré / François Delécluse: Spatial treatment of sound in the Polytope of Cluny by Iannis Xenakis

During the 60s and 70s, Xenakis conceived several shows mixing music, architecture and performance called « Polytopes ». In the Polytope de Cluny (1972-1974) in particular, the most advanced technologies of the time were employed to imagine a new synergy between music, space and light. During this twenty five minutes long installation, concrete tape music flowed under the arches of the ancient roman therms of Cluny (Paris) while interacting with visual patterns created by an array of hundreds of flash lights and laser beams. In order to synchronise the diffusion of the different audio tracks among the many loudspeakers together with the luminous ballet, Xenakis had a custom technical apparatus designed, that relied at its core on a monotasking computer decoding in real time the digital data stored on a command tape. However, the technologically avant-garde nature of this work, together with the temporary character of the show and its prohibitive cost, was the very reason why it was never to be played again. Due to the scarcity of the remaining original material, it was long thought that the Polytope was lost. However, the digital command tape of the show was recently rediscovered, and its cross-examination against archival documentation available at the Archives Xenakis (technical documentation, letters, photographs, videos, drawings, etc) opened new perspectives for the reconstitution of the Polytope.

This presentation is part of two main axes: first, the re-creation of the Polytope de Cluny at IRCAM as part of the Xenakis centenary, and second, the perpetuation of the work in its entirety in the form of critical documentation. The stakes of the recreation of the work imply first of all the access to the different sources and to the technical resources allowing the reading and the exploitation. Then, reading these sources certainly allows access to the essential information for the recreation of the work, but those need to be interpreted in order to compensate for their possible shortcomings as well as the potential imperfections of a material already altered by time. The critical description of these sources invites us to put the documentation of the work into perspective in order to guarantee its durability beyond the project of recreation at IRCAM. In this respect, we will propose some ideas concerning the storage of information that is not destined to fall into disuse. A third, more general issue concerns the obsolescence of the technologies used at the time of the creation of the work in 1972: it seems important to describe the result aimed at by Xenakis as much as the means implemented at the time, which could suffer from various defects (for example., the levels of the loudspeakers were sampled over four predefined values and could not be completely silent). This problematic cannot avoid a global reflection on the notion of authenticity of works in the context of electronic music.

Pierre Carré
Both a musician and a mathematician, Pierre Carré pursued a twofold education that led him to a Mathematics PhD at IRCAM, while studying musicology, music writing and orchestration at the CNSMDP. Since 2016, he has been working with Mâkhi Xenakis to promote the archives of her father Iannis, which led him to produce several essays on the work of Xenakis. On the basis of his work on the archives, he will be performing the sound and light show Polytope de Cluny at IRCAM in 2022 for the first time since its creation fifty years ago.