Pierre Boulez wrote Polyphonie X during the phase of his career when he was most concerned with applying a rigorous, strict serial method to his creative musical urges. Other pieces from this same period (1949 - 1952) include his Livre pour Quatuor (string quartet), Structures, Book One (two pianos), and two electronic tape works, Étude Sur Un Son and Étude Sur Sept Sons. These works are characterized by highly pointillistic textures and irregular rhythms.
Polyphonie X, completed in 1951, began shape as a piece for much larger forces, seven groups of seven instruments (forty-nine in all). In the end, the ensemble was boiled down to 18: 11 winds and seven strings, all treated as soloists. The serial structure is applied to both the pitches and the rhythms, and the music is conceived as strands ("polyphonies") of linear (melodic would be too strong a word) bundles unfolding according to independent series of rhythmic durations. Over its sixteen-minute duration, Polyphonie X shifts perceptibly from one section to another, each governed by a different horizontal and vertical density (in other words, the number of notes sounding per second or other unit of time). The strands of polyphony are highly disjunct, so there is much overlap from one to another. The changing instrumental colors, rather like a sonic kaleidoscope, provide a means for a careful listener to distinguish between things. While the sections proceed at times in frenetic and at times in relaxed fashion, there is little or no sense of forward motion or dramatic narrative. This is music of the hard-nosed 1950s, when abstract, structural thinking took prime place over other considerations such as melodiousness or dramatic engagement.
Boulez himself was unable to attend the premiere of Polyphonie X in Baden-Baden, Germany, performed by Hans Rosbaud and the SWF Symphony Orchestra. When he at last heard a recording of it -- and it was by all accounts a fine, dedicated performance -- Boulez decided he wasn't satisfied with the score. He withdrew it from his catalog and it has remained thus ever since. In the case of this composer, most such withdrawals are provisional, so it is possible that he will revise it and bring it out again. He in any case did not prevent Col Legno from issuing a recording of the original performance. Polyphonie X remains of historic interest for exemplifying, in ambitious form, the technical and musical concerns of the young Pierre Boulez as he searched for an integral compositional style.