 Eicher mixed the album with Favre at Idee Und Klang Studio, Switzerland.Throughout "Fleuve", the ensemble has a naturally deep bottom end, due to Favre's drums, Oëster's double bass, Zwiauer's bass guitar and Godard's tuba and serpent playing, with the middle- to high-end instrumentation courtesy of Schaufelberger's guitar, Kroll's soprano saxophone and bass clarinet and Breschand's harp.Despite featuring very bottom-heavy instrumentation, the music has been noted by critics for its light, airy, ethereal sound.