Vers le blanc, composed at the Ircam in 1982, is the work that marked the anchoring of the composer's thought in the potentialities of electronics. One identifies two important concerns, for the progressive transformation of one material into another, and for the creation of harmonic fields on the basis of methods of sound analysis, realising a transition from timbre to harmony. Such concerns are found again in L'Amour de loin, whose electronic sounds have been realised in the Ircam studios with the help of the softwares Open Music and MAX/MSP. The sound materials are vocal and instrumental samples analyzed by resonance models. Individual harmonic structures are associated with each of the characters. Synthesis filters cross the harmonic structures with the resonance models. The sounds so realised are mixed in real time with the help of the spatialisator developped in the Ircam, and broadcast through a network of loudspeakers.