He composes works for acoustic instruments as well as electronic resources. While living in Ann Arbor, Michigan, Mumma co-founded the Cooperative Studio for Electronic Music and the ONCE Festival of Music with Robert Ashley. In 1966 Mumma formed Sonic Arts Union with Robert Ashley, David Behrman, and Alvin Lucier. From 1966 to 1974 Mumma, along with John Cage and David Tudor, was a composer and musician with the Merce Cunningham Dance Company.