Makis Solomos translation from the French: Jennifer Higgins Possibly the most important musical revolution of the 20th and 21st centuries has been the emergence of sound, and the ever-greater importance accorded to it (see Solomos 2019). Xenakis occupies a special place in this development, whereby, to put it simply, composition of sound has tended to […]


Makis Solomos translation from the French: Jennifer Higgins When Xenakis creates compositional implementations of theoretical models, he frequently “intervenes” and introduces many “discrepancies.” All Xenakis specialists, when comparing the theoretical models with the scores, have noted that there are important “gaps” between the data predicted by the former and the data found in the latter. […]

Undulating glass panes

Elisavet Kiourtsoglou Undulating glass panes consist in an assemblage of glass panes of various lengths; they were used for the first time for the Monastery of Sainte Marie de la Tourette (1953-1961). The project was assigned to Le Corbusier (1889-1967) by the Dominican Friars’ Community of Lyon, in an attempt to modernize the architecture of […]

Ruled surfaces

Elisavet Kiourtsoglou In geometry, a surface is ruled if a straight line (skew line) passes through each one of its points. The cylinder, the cone, the helicoid, the hyperbolic paraboloid, the conoid and many other three-dimensional shapes follow the above mathematical definition. Xenakis (1958) first referred to the properties of ruled surfaces during his collaboration […]

Outside of time

Dimitris Exarchos In the early 1960s Xenakis developed a compositional theory based on the observation that certain musical structures are independent of time. His approach to this matter was, among others, a critique of those traditional conceptions that emphasize the temporal dimension of music. He insisted that all music has an aspect outside of time […]


Pierre Carré Xenakis grouped together under the term polytopes a series of various shows that mixed music, light and architecture in a total sensory experience: the Polytopes of Montreal, Persepolis, Cluny, Mycenae, and the Diatope. Although they share the same name, these shows, produced between 1967 and 1978, take very different forms depending on the […]

Stochastic Synthesis

Peter Hoffmann This technique refers to a method of computer sound synthesis. The original conception dates back to 1962, when Xenakis was working with his ST algorithm, resulting in the stochastic compositions ST/x (see Stochastic Music). Stochastic synthesis rejects Fourier analysis or pure electronic sounds and favors applying stochastic processes directly to the sound pressure […]


Agostino Di Scipio In the mid-1970s Xenakis began developing the UPIC system, a computer music system having a drawing surface as input device: drawings made on a CAD-like tablet (Computer Assisted Design) could be made into sounds through a software interface, a dedicated processor and a digital-to-analogue converter. UPIC (Unité Polyagogique Informatique du CEMAMu [Centre […]

Granular Synthesis

Agostino Di Scipio In the jargon of electronic and computer music, granular synthesis refers to a vast range of sound synthesis and processing techniques sharing a common basic assumption: in principle, any sound can be modelled by juxtaposing and piling up large amounts of grains, the latter being defined as time-finite signals of given frequency […]

Cellular Automata

Peter Hoffmann A cellular automaton (CA) governs, among others, only a few bars in Horos (1986) and, through an act of self-borrowing, in Ata (1987) (see Solomos 2006); however, this late example of a musical appropriation of a scientific model is particularly telling for Xenakis’s passion for science, mathematics and computation on the one hand […]