Before an audio revolution in the mid-1960s, just about all music, dialogue and other sounds played on tape recordings had one thing in common: hiss.
The bothersome, underlying noise seemed especially unavoidable during quiet passages on the once-ubiquitous cassette tapes.
But then came an engineering breakthrough that nearly wiped out the hiss, and made the inventor's name — Dolby — world-famous.
Ray Dolby, 80, died Thursday at his home in San Francisco. The company he founded, Dolby Laboratories, released a statement saying he had been suffering from Alzheimer's disease in recent years and in July was found to have acute leukemia.
The Dolby Sound System was first used commercially in recording studios nearly 50 years ago and then adopted by the film industry.
"You could divide film sound in half: there is BD, before Dolby, and there is AD, after Dolby," said Oscar-winning film and sound editor Walter Murch last year at the Hollywood Post Alliance Awards that honored Dolby.
Eliminating hiss, along with other sound enhancements invented by Dolby, allowed filmmakers to use far more sophisticated multi-track, surround-sound audio to transport audiences into fantasy worlds.
Perhaps no movie used this technology, in its early days, more effectively than "Star Wars" in 1977.
"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," the film's director, George Lucas, said in a statement Thursday.
Murch agreed. "'Star Wars' kicked it into another realm," he said Thursday, also citing "Apocalypse Now" and "Close Encounters of the Third Kind" as films whose impact probably would have not been the same without Dolby.
Although Dolby's original audio developments have been supplanted by digital sound regimens, Dolby Labs' products are still used in movie theaters, recording studios and consumer electronic devices around the world. More than 7.4 billion consumer products use Dolby technologies, according to the company, including personal computers, mobile devices and video game machines.
Last year, the Dolby name got another boost when it was placed atop the Hollywood theater from where the Oscars are telecast.
But Ray Dolby will probably be best remembered as the man who changed recorded sound.
"You saw a tape machine and saw 'Dolby,'" said British sound engineer John Kurlander, who worked on the Beatles' "Abbey Road" among numerous records and film tracks, "and they became inseparable."
Ray Milton Dolby was born Jan. 18, 1933, in Portland, Ore., and his family moved to Palo Alto while he was still a boy. He took an early interest in music.
"I started playing the piano at 10, then moved to clarinet so I could play in the school orchestra," he told The Times in 1988. "Mainly, though, I was fascinated by the technology of music: how organs worked, how reeds vibrated, why things sounded the way they did."
While still in high school, he started working for the ground-breaking Ampex Corp. in Redwood City that made audio tape recorders and was developing new uses for magnetic tape. "I made a deal with my high school," Dolby said. "I was so far ahead in my credits that I didn't have to worry about getting into college, so I went to school three hours a day and worked five at Ampex."
He worked at the company with Charlie Ginsburg, who headed a small team that developed the first broadcast-quality videotape recorder, according to an MIT profile. Ginsburg, who died in 1992, said in a 1988 Times interview that Dolby played a vital role.
"I'd say that Ray essentially was the inventor of that whole system," Ginsburg said. "He had virtually no formal education then, no college, but he was already an outstanding inventory."
Dolby was also demonstrating a keen business sense at a young age. He didn't like to be called a "tinkerer" exploring new ideas for the sake of it. His work was more focused on an outcome. "An inventor knows what he wants to do," he said. "An inventor has to have taken out a patent.
"I had my first one at 19."
After serving in the Army, Dolby graduated from Stanford University in 1957 with a bachelor's degree in electrical engineering and went on to Cambridge University in England where he received a doctorate in physics. He also met his wife, Dagmar, at the university where she was a summer student from Germany.
In 1963 he was eager to leave academia and embarked on a two-year appointment in India as a UNESCO science advisor. It was in that country, while working on noise-reduction systems, that he had a revelation regarding hiss. It involved separating high and low frequencies in order to clean out the noise. In a 1979 interview with Fortune magazine, he said the system "increases the desired tones, suppresses hiss and recombines the cleaned frequencies into very high-fidelity sound."
At the end of his India stint, he established the original Dolby Laboratories in London at a cost of $25,000. Last year, according to the company's fiscal 2012 annual report, it had sales of $926 million.
Dolby stepped down as chairman of the San Francisco company in 2009. He and his wife contributed to Bay Area charities, including $36 million to UC San Francisco for stem cell research.
Dolby is survived by his wife of 47 years, sons Tom and David and four grandchildren.
Times staff writers Elaine Woo and Devin Kelly contributed to this report.