Opéra de Monte-Carlo, Salle Garnier

Durée approximative 1h10

Iannis Xenakis
Rebonds, pour percussionniste solo
Psaphha, pour percussionniste solo
Okho, pour trois musiciens
Persephassa, pour six percussionniste

Trio Xenakis et Collectif Xenakis

The quintessence of rhythm

Xenakis’s encounter with percussion took place under the prestigious auspices of a commission for Les Percussions de Strasbourg, in 1969, from the Shiraz-Persepolis Festival of Arts. Persephassa (the ancient name for Persephone, goddess of cycles and of the rebirth of nature in the spring) was first performed on September 9, in the ruins of the Palace of Darius, in Persepolis. Distributing the six percussionists in a ring around the audience, each equipped with the same set of instruments, Xenakis creates what he calls a “cinematic sound”, by continuous displacement of sound around the circle (as at the end of the piece) or by distributing the strokes at different points, according to geometrical figures (diagonals, triangles, etc.). Apart from brief interventions from mouth sirens, the instrumental colors are confined to natural timbres (skins, wood, metals and stone) and the polyrhythmic constructions are produced by superimposing (like in a gear-like fashion) simple cyclic structures, which shift in relation to one another, becoming gradually denser and more irregular.

For Xenakis, rhythm is not about regular repetition but about the dialectic of regularity and irregularity. As early as 1951, in his notes on Hindu music, which he described as representing “the most civilized and perfect organization of rhythm,” he was wondering about the balance of regularity and irregularity that a rhythmic structure must consist of if it is to retain the listener’s attention. “Any cell or complex of rhythmic cells repeated for a long time loses its interest (…). Any subtle modification arouses the mind (…). The mind is baffled at the moment the change occurs. But it quickly gets used to it and the fact that it understands the meaning of its new state makes the phenomenon pleasing, for it has mastered the new rhythm.” Despite their early date, these notes, written when he had not yet produced any significant work, remain one of the keys to Xenakis’s rhythmic thinking.

This idea of installing a mechanism (called an “ordering structure” by Xenakis) then introducing elements that break the regularity is found in Psappha (1975), for a single percussionist. “To launch a mechanism, let it be outlined, then to change it = pirouette,” notes the composer in the sketches for this work. In Psappha, Xenakis plays with this paradox in numerous ways: regular pulse with the introduction of unexpected figures, on which irregular accents are superimposed; cyclical permutations of three timbres that suddenly “go haywire;” variation of the number of successive strokes in the same timbre, etc.

Rebonds A and B, a composition in two parts that can be played in the order the performer chooses, was first performed (as was Psappha) by Xenakis’s tireless interpreter Sylvio Gualda. Rebonds B, composed in 1987-88, was premiered in July 1988, in Rome, on its own, then both were performed in the courtyard of Avignon’s Palais des Papes, on July 24, 1989. Apart from a set of five woodblocks, Xenakis uses only skins. The reduction of the range of instruments to a single timbral color aims at a focus on pure rhythm. As in Psappha, the composer launches a mechanism then gradually disrupt its regularity. Rebonds B starts with two superimposed lines, each with a well-characterized cell, which is subjected to permutations. Irregularity is introduced by displacing accents and varying the number of successive strokes. Rebonds A, on the other hand, is based on the complexifying and gradual densifying of basic cells.

With Okho, Xenakis took a further step in the austerity of his writing for percussion. It was composed in June and July 1989, just after Rebonds A, for the Le Cercle trio, which premiered it on October 20, in Paris, as part of the Festival d’Automne. Lasting almost fifteen minutes, the work is scored for just three djembes (with the possibility of doubled up) and a “large African skin drum,” as Xenakis described it. Different timbres are created by the use of six main playing modes – on the rim (brighter sounds) or in the center (low sounds) – with some variants. Here, the dialectic is woven around the unchangingly regular pulse (except at the very end) and the irregularity of subtle timbral alternations, here obtained with the help of technology, since Xenakis organizes them using data from a computer program.

From Persephassa to Okho, Xenakis gradually became less seduced by the sheer sonic resources of percussion and moved towards a very pure style, distilled down to the quintessence of alternations and numbers – the “power and dynamism” of which he had already sensed forty years earlier, when studying Hindu rhythm. Anne-Sylvie Barthel-Calvet

Photo Collectif Xenakis ©Jean-Baptiste Jacquet Contenu