Répons

Répons is a composition by French composer Pierre Boulez for a large chamber orchestra with six percussion soloists and live electronics. The six soloists play harp, cimbalom, vibraphone, glockenspiel/xylophone, and two pianos. It was premiered on 18 October 1981 at the Donaueschingen Festival. The composer expanded it until its completion in 1985. The work is dedicated to "on his 80th birthday".

Répons was the first significant work to come out of Boulez's endeavors at IRCAM, an institute in Paris devoted to making technological advances in electronic music. It has been celebrated for its integration of the electronic and the acoustic. Its title, Répons, reflects the fact that the composition is constructed on various types of responses: the acoustic sounds and electronic responses to them as well as the medieval idea of responsorial mirroring between players and speakers in different parts of the concert hall.

Répons is subdivided into an Introduction, Sections 1–8 and a Coda. Of the use of metre and harmony in Répons Boulez said:

Oh yes, there is a metre, slightly irregular on one level but very regular on another. There are so many irregular things in this piece that at one point you need to have a regular metre as you say – a bass and a regular pulse anyway – but also a series of harmonies which are all symmetrical. The harmony always gives this impression of something followed by its inverse; there is always a centre – an axis of symmetry. This symmetry of harmony corresponds in harmonic terms to a regular metre. This is very important. There are three types of time. That which is chaotic and irregular such as you have in the beginning (in the speed I mean). Then you have, in the speed, the very regular rapid repeated notes – always in semiquavers. Finally at the end there is a regularity, a kind of metre – but with much ornamentation. The ornamentation is in fact very irregular, but the metre itself is very regular.

The pitches of the row used in Répons are those based on the Sacher hexachord and used in the rows for several other Boulez compositions: Messagesquisse, Dérive 1, Incises, and Sur Incises.

Boulez selected the solo instruments, all pitched percussion, based on the ability of the computer equipment to "exploit their resonating characteristics to the limits of the technology available at the time".

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