Horos (For large orchestra width 89 players))

Iannis Xenakis – Horos – 1986 / for large orchestra

« Another approach to the mystery of sounds is the use of cellular automata which I have employed in several instrumental compositions these past few years. This can be explained by an observation which I made: scales of pitch (sieves) automatically establish a kind of global musical style, a sort of macroscopic « synthesis » of musical works, much like a spectrum of frequencies, or iterations, of the physics of particles. Internal symmetries or
their dissymmetries are the reason behind this. Therefore, through a discerning logico-aesthetic choice of « non-octave » scales, we can obtain very rich simultaneities (chords) or linear successions which revive and generalize tonal, modal or serial aspects. It is on this basis of sieves that cellular automata can be useful in harmonic progressions which create new and rich timbric fusions with orchestral instruments. Examples of this can be found in
works of mine such as Ata, Horos. » Iannis Xenakis 1992