18 musicians

Gerard Grisey’s Les espaces acoustiques is one of the seminal works of the spectral music school. “Everything began with Périodes,” said Grisey in an interview with Guy Lelong. “From a formal point of view, this piece consists of a succession of episodes, in the last of which I experimented for the first time with a technique the seemed to me in need of development. I had analyzed, with the help of a spectrogram, the sound of the trombone’s E and created its main components (the fundamental and its harmonics) with the instruments of Périodes. That opened my eyes to a new way of harmonic thinking and which I later called “instrumental synthesis.” I then had to write a sequel, and this turned out to be Partiels for 18 musicians (1975) which includes the instruments of Périodes. Then I finally decided to compose a whole cycle that would begin with a piece for solo instrument and finish with a large orchestra. As the viola played a prominent role in Périodes, the solo piece had to be written for this instrument, and it was Prologue for solo viola.”

The title of Partiels refers both to the movement’s place within a larger work, as well as to the acoustic components of sound. Like Périodes, the piece continues to embody the cyclical form of human breathing, but now Grisey embraces a new technique, that of instrumental synthesis. This writing style uses micro-synthesis of the individual instruments’ sounds to express different elements of an overall macro-synthesized sound. As a result, the listener loses track of the source of individual sounds in the resulting composite. These different mergings allow for the articulation of a whole range of timbres from the spectrum of harmonics to white noise, all by way of different combinations of the partials.