Stephan Mathieu is a German mastering engineer. He operates Schwebung Mastering, preparing audio for analog and digital products, streaming media, and restoring archival material.

From 1989 to 2016, he was active as a musician, from 1989-98 as a drummer, then working in electroacoustic music and sound installation. Mathieu's sound is primarily based on early instruments and obsolete media, which are recorded and transformed utilizing experimental microphony, re-editing techniques, and dedicated software processes. His music has been released solo and in collaboration with Taylor Deupree, Ekkehard Ehlers, Fennesz, Robert Hampson as Main, Akira Rabelais, and David Sylvian on 12k, Editions Mego, Grönland, Line, and his Schwebung imprint.