Composer and improviser, Xavier Garcia has produced around thirty electro-acoustic creations at the Groupe de Recherches Musicales, at the Groupe des Musiques Vivantes in Lyons, and in his own studio. A member of the ARFI since 1987, he has performed sound sampling and sound treatment in collaboration with musicians like Brian Eno, Heiner Goebbels, Chris Cutler, and Lorenzo Recio. Lionel Marchetti is a composer of acousmatic and concrete music and an experimental improviser with diverse electronic instruments. His musical compositions are considered to be cinema for the ears. Whether in acousmatic music, sound treatment or concrete music, the approach of these researchers is more hands-on than scientific. Their sounds are more forged than treated, the better to twist them, to mold them, like alloys. Goldsmiths in sound, they chisel raw materials, numerically for one, analogically for the other.