Xenakis - Pithoprakta

I'm not a fan of most 20th-century or experimental music, but this piece by Greek-French composer Iannis Xenakis, entitled Pithoprakta, meaning 'actions through probability' [1], is oddly intriguing to me. Xenakis was fascinated with blending mathematics and architecture into music, and frequently drew from mathematics, physics, and acoustic science in his work.

Pithoprakta uses ideas from statistical mechanics, a branch of physics which combines probability, statistics, and classical mechanics (Newtonian physics). For example, a gas at a given temperature has molecules moving at many different speeds, spread over a distribution called the Maxwell-Boltzmann distribution. Information on these individual molecules can be used to calculate properties (temperature, pressure, etc.) of larger systems [2]. In Pithoprakta, Xenakis evokes large-scale musical gestures from individual instrumental parts which -- like single molecules of a gas -- are meaningless. There is no "melody;" instead, the piece advances in a musical direction with solo parts (forty-six separately scored string parts, two trombones, xylophone, and woodblock) that sound random and as if lacking any musical quality on their own.* Read more about this piece here from pages 13-17 [3].

The piece makes use of unconventional and extended techniques for string instruments including combined glissando and pizzicato, col legno (tratto) ([bowing with] the wooden side of the bow), col legno battuto (bouncing the wooden side of the bow on the strings), and frappe (tapping the soundbox/belly of the instrument for percussive effect). Although there is virtually no traditional harmony, there is still a strong sense of musical direction, developing at rapidly different paces in different sections, throughout the piece. The graphical score in the video linked above is an interesting "read."

*Depending on your taste, you might argue the whole piece lacks any musical quality ... explore the piece anyway! Like me, maybe you'll find some interesting features you enjoy. :)

Some of my observations/opinions:
- I find the pizzicato flurry from 2:38-2:57 fun to listen to.
- From 2:58-4:50, the color of the drone subtly changes as string parts drop out - under the sharpness of the xylophone and pizzicato, the changes are so slight as to be nearly imperceptible.
- The col legno segment from 5:28-7:22 has so many textures embedded in it. Sometimes you can just barely hear the col legno tratto (it's really hard to pick out with all of the battuto sounds). It sounds to me like a dangerous forest with poisonous vines snaking ... and the trombones at 7:22 only add to the tension.
- Wide sweeps from 8:27-9:21 with four different bowing techniques sounds so wacky as they fade in and out from register to register.

1. Harley, J. (2004). Xenakis: His Life in Music. Routledge. ISBN 0-415-97145-4.

2. McQuarrie, D. A.; Simon, J. D. (1997). Physical Chemistry: A Molecular Approach. University Science Books, Sausalito (USA).

3. Xenakis, I. (1992). Formalized Music: Thought and Mathematics in Composition. ISBN 9781576470794.