Keith O. Johnson

Keith O. Johnson, known in the audio press as "Professor" Johnson, is an American recording engineer and audio equipment designer. A founding partner of the classical label Reference Recordings, he built much of the equipment used for its sessions and engineered its releases. With Michael "Pflash" Pflaumer he developed High Definition Compatible Digital (HDCD), a coding system for the compact disc commercialized by Pacific Microsonics and acquired by Microsoft in 2000. He has won one Grammy Award from thirteen nominations.