He is a specialist in multi-channel audio and spatialization. As a composer of acoustic music, Mercer has focused on extended instrumental techniques, modifying conventional instruments, and instruments of the composer's own design and, most recently, combining this approach with real-time electronics and spatialization. He is the author of articles on musical aesthetics and composition and has had residencies at Experimentalstudio SWR in Freiburg, Künstlerhaus Schloss Wiepersdorf, and Sound Traffic Control in San Francisco. Mercer’s principal teachers were Peter Otto and Roger Reynolds, electronic music, and Chaya Czernowin and Chinary Ung for instrumental music.