The soloist here is a ring-modulated Ondes Martenot (the French electronic instrument used in Messiaen's Turangalîla-Symphonie as well as in several of Murail's works), partnered by a small orchestra of some thirty players. The form is very similar to that of Ethers (there are direct parallels between sections in each piece) but the materials in Les Courants are more complex than in either of the preceding works. The rich complexes of sum and difference tones produced by the ring-modulated ondes furnish the orchestra's harmonic material. These complexes are half-harmonic, half-timbral in character, and the piece constantly plays upon the ambiguity between harmony and timbre: a complex perceived as timbre when produced by the ring-modulated soloist is transformed into a predominantly harmonic phenomenon when transferred on to the orchestra. As in a classical concerto, the soloist and the orchestra have the same theme in turn (second and penultimate sections) and this time both participate in the processes of distortion and transformation. The sound of the Ondes Martenot is further transformed by phase-shifting, producing sweeps of harmonics mirrored in the orchestra's circling arpeggios (spectrum on D near the end) - and an envelope-shaper helps the ondes imitate the soft "wa" of the brass with harmon-mutes. Even more than in Ethers, the tempo is constantly accelerating or decelerating, which lends the music a strangely dilated temporal character - nowhere more than at the dramatic conclusion, where a huge decelerating process is suddenly cut off, leaving the work open-ended.
1 CD Accord,
Mémoire/Erosion - Ethers - C'est un jardin secret, ma soeur, ma fiancée, une source scellée, une fontaine close... - Les Courants de l'espace
Alain Noël (horn), Ensemble l'Itinéraire, Charles Bruck (conductor) - Pierre-Yves Artaud (flute), Ami Flammer (violin), Geneviève Renon (viola), David Simpson (cello), Joëlle Léandre (doublebass), Christian Marchand (trombone), Jacques Mercier (conductor) - Sylvie Altenburger (viola) - Jeanne Loriod (ondes Martenot), Orchestre National de France, Yves Prin (conductor)