Ray Dolby, a pioneering sound engineer who removed the hiss from audiotapes and whose innovations brought surround-sound into movie theaters and altered the recording industry, died Sept. 12 at his home in San Francisco. He was 80.

His company, Dolby Laboratories, said in a statement that he had Alzheimer’s disease and had recently developed acute leukemia.

Dolby made many key developments in audio design, and his name appears in movie theaters around the world and on countless other products, from video games to DVD players to hand-held devices, that use technology designed by his company.

He first found renown in the mid-1960s, when he invented a “noise reduction” system that virtually eliminated the annoying hiss that was the underlying sound on audiotapes. It allowed musicians to produce recordings of almost pristine audio quality and was first used on a recording of Vladimir Ashkenazy playing Mozart piano concertos.

Among other applications, the technology simplified the practice of multitrack recordings. Although Dolby was an amateur clarinetist and an aficionado of classical music, his technology quickly developed a following among rock musicians. The Grateful Dead reportedly purchased an early version of his multitrack recording device with a suitcase filled with cash.

In 1977, the movie-going public began to experience Dolby’s innovations when two popular films, “Close Encounters of the Third Kind” and “Star Wars,” were released. The soundtracks were recorded in multichannel formats that could create an enveloping sensory experience that came to be known as “surround sound.” Thousands of theaters around the world were rebuilt with sound systems designed by Dolby’s company.

“Ray’s pioneering work in sound played a pivotal role in allowing ‘Star Wars’ to be the truly immersive experience I had always dreamed it would be,” George Lucas, the director of “Star Wars,” said in a statement.

Dolby and his company won multiple Oscars, Emmys and Grammys for technical aspects of sound production.

At the 2012 Academy Awards, when the auditorium in which the awards are presented was named for Dolby, Oscar-winning sound editor Walter Murch said his influence was incalculable: “You could divide film sound in half: There is BD, Before Dolby, and there is AD, After Dolby.”

Thomas Robertson, a British musician best known for the 1982 hit “She Blinded Me With Science,” adopted the stage name of Thomas Dolby because of his fascination with Dolby’s audio equipment. (To add to the confusion, Mr. Dolby had a son named Thomas. By contractual arrangement, the British Thomas Dolby could not produce or endorse any audio devices.)

In the 1980s, when digital technology began to alter the recording and movie industries, Dolby found himself behind the technological curve. While he concentrated on refining older analog forms of sound production, other companies stepped into the void. Since the 1990s, however, Dolby Digital regained a large share of the theater market and became the leading maker of sound technology used in home electronics.

Dolby had more than 50 patents, but he charged little for his technology. As a result, producers of sound equipment found it cheaper to use his technology than to try to copy it.

“If it was cheaper for manufacturers to license from us than clone us, why not stick with the Dolby technique?” he said in 1992.

Last year, Dolby Laboratories had total sales of $926 million. Dolby’s personal fortune was estimated at more than $2 billion.

Ray Milton Dolby was born Jan. 18, 1933, in Portland, Ore., and grew up in Palo Alto, Calif. His father was a real estate broker who liked to tinker in his home shop and invited his son to join him.

“When I was 11,” Dolby told the Los Angeles Times in 1988, “I offered to pull the cylinder head of my dad’s ’32 Plymouth and do a valve job for him. I started in the morning and finished that night, alone.”

He was also interested in music from an early age and played the piano and clarinet.

“Mainly, though,” he said, “I was fascinated by the technology of music: how organs worked, how reeds vibrated, why things sounded the way they did.”

In his teens, he began working for the Ampex tape-recording company, and he had a major role in developing the first videotape recorder before he turned 21.

He served in the Army in the 1950s and graduated from Stanford University in 1957. He then worked as an engineer in England, where he received a doctorate in physics from the University of Cambridge in 1961.

While working for UNESCO in India, where he was recording local music from 1963 to 1965, Dolby conceived of a way to boost the sound levels of soft musical passages to eliminate the tape hiss. He then adjusted the sound levels for the final version of the recording, resulting in a virtually hiss-free musical experience.

He founded his company in London in 1965 and used generic names for his technology until he overheard a conversation on an elevator.

“I heard an engineer say, ‘We have to take the Dolbys from Studio A to Studio B,’ ” he once recalled. “My hair stood on end. I’d never heard my name used that way.”

From then on, his name was synonymous with sound equipment. In 1976, he moved his company to San Francisco, where he served on the boards of the city symphony and opera and contributed millions of dollars to education and medical research.

Survivors include his wife of 47 years, Dagmar Baumert Dolby of San Francisco; two sons; and four grandchildren.

Dolby resented being called a “tinkerer” and considered himself an inventor in the classic mold of Thomas Edison and the Wright brothers.

“A tinkerer is someone who hopes to discover or invent something on an unprepared basis,” he said in 1988. “An inventor knows what he wants to do.”