Thomas Stockham, 70, audio pioneer

SALT LAKE CITY -- Thomas G. Stockham Jr., a pioneer researcher of digital sound recording who won a technical Oscar and helped investigate President Nixon's mysterious 18-minute tape gap, died Tuesday from complications of Alzheimer's disease. He was 70.

Dr. Stockham, an electrical engineer, and the late Robert B. Ingebretsen, who had been his graduate student, did pioneering work in the 1970s on converting analog sound to a digital format. They received a Scientific/Engineering Academy Award in 1999.

In 1972, Dr. Stockham was one of the experts hired to try to examine the 18-minute gap on one of Nixon's secret White House tapes.

In 1975, he founded Soundstream Co. in Salt Lake City. He was joined by Ingebretsen, and they developed technology that was instrumental in the creation of the compact disc.