In 1954, Dr Cooper joined the Coordinated Sciences Laboratory at the University of Illinois, where he became a research professor. He developed a unified treatment of phonograph tracking and tracing distortion by utilizing a skew transformation. In the late 1960s and early 70s, Dr Cooper contributed significantly to the theory of surround sound multi-channel stereo.
Dr Cooper served as president of the Audio Engineering Society (AES) from 1975-1976. He was named an AES Fellow in 1966, and received the AES Silver and Gold Medals.