Metastasis, also Metastaseis, is an orchestral work for 61 musicians by Iannis Xenakis. His first major work, it was written in 1953-54 after his studies with Olivier Messiaen and is 8 minutes in length. The work was premiered at the 1955 Donaueschingen Festival with Hans Rosbaud conducting.
Metastasis was inspired by the combination of an Einsteinian view of time and Xenakis' memory of the sounds of warfare, and structured on mathematical ideas by Le Corbusier. Music usually consists of a set of sounds ordered in time; music played backwards is hardly recognizable. Messiaen's similar observations led to his noted uses of non-retrogradable rhythms; Xenakis wished to reconcile the linear perception of music with a relativistic view of time. In warfare, as Xenakis knew it through his musical ear, no individual bullet being fired could be distinguished among the cacophony, but taken as a whole the sound of "gunfire" was clearly identifiable. The particular sequence of shots was unimportant: the individual guns could have fired in a completely different pattern from the way they actually did, but the sound produced would still have been the same. These ideas combined to form the basis of Metastasis.
The work requires an orchestra of 61 players (12 winds, 3 percussionists playing 7 instruments, 46 strings) with no two performers playing the same part. It was written using a sound mass technique in which each player is responsible for completing glissandi at different pitch levels and times. The piece is dominated by the strings, which open the piece in unison before their split into 46 separate parts.
As Newtonian views of time show it flowing linearly, Einsteinian views show it as a function of matter and energy; change one of those quantities and time too is changed. Xenakis attempted to make this distinction in his music. While most traditional compositions depend on strictly measured time for the progress of the line, using an unvarying tempo, time signature, or phrase length, Metastasis changes intensity, register, and density of scoring, as the musical analogues of mass and energy. It is by these changes that the piece propels itself forward: the first and third movements of the work do not have even a melodic theme or motive to hold them together, but rather depend on the strength of this conceptualization of time.
The second movement does have some sort of melodic element. A fragment of a twelve-tone row is used, with durations based on the Fibonacci sequence. (This integer sequence is nothing new to music: it was used often by Bartók, among others.) One interesting property of the Fibonacci sequence is that the further into the infinite sequence one looks, the closer the ratio of a term to its preceding term comes to the Golden Section; it doesn't take long before the result is correct to several significant figures. This idea of the Golden Section and the Fibonacci Sequence was also a favorite of Xenakis in his architectural works; the Convent de La Tourette was built on this principle.
Xenakis, an accomplished architect, saw the chief difference between music and architecture as that while space is viewable from all directions, music can only be experienced from one. The preliminary sketch for Metastasis was in graphic notation looking more like a blueprint than a musical score, showing graphs of mass motion and glissandi like structural beams of the piece, with pitch on one axis and time on the other. In fact, this design ended up being the basis for the Philips Pavilion, which had no flat surfaces but rather the hyperbolic paraboloids of his musical masses and swells. Yet unlike many avant-garde composers of this century who would take such a thing as the completed score, Xenakis notated every event in traditional notation, leaving nothing to the performers' discretion alone.
A ballet was choreographed to Xenakis' Metastasis and Pithoprakta by George Balanchine; the work was premiered on January 18, 1968 by the New York City Ballet with Suzanne Farrell and Arthur Mitchell.