engineering

Ray Dolby

Ray Dolby is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Ray Dolby rather than just read about it. In short: Ray Milton Dolby (; January 18, 1933 – September 12, 2013) was an American engineer and inventor of the noise reduction system known as Dolby NR, which has been said to have "transformed sound reproduction". In the 1950s he contributed to development of the video tape recorder while at Ampex, and in 1965 he founded Dolby Laboratories in London.

Key takeaways

Ray Dolby belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Ray Dolby to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Ray Dolby from memory before moving on to harder problems.

Reference excerpt

Ray Milton Dolby (; January 18, 1933 – September 12, 2013) was an American engineer and inventor of the noise reduction system known as Dolby NR, which has been said to have "transformed sound reproduction". In the 1950s he contributed to development of the video tape recorder while at Ampex, and in 1965 he founded Dolby Laboratories in London. There he invented and patented a method of noise reduction for use in analog recording which was widely adopted for the cassette tape. The company moved to California in 1976 and went on to develop audio and video formats for films, home video recorders, home theater, television broadcasts, and video streaming services.

Early life and education Dolby was born in Portland, Oregon, the son of Esther Eufemia (née Strand) and Earl Milton Dolby, an inventor. He attended Sequoia High School (class of 1951) in Redwood City, California. As a teenager in the decade following World War II, he held part-time and summer jobs at Ampex in Redwood City, working with their first audio tape recorder in 1949. While at San Jose State College and later at Stanford University (interrupted by two years of Army service), he worked on early prototypes of video tape recorder technologies for Alexander M. Poniatoff and Charlie Ginsburg. In 1957, Dolby received his B.Sc. in electrical engineering from Stanford. He subsequently won a Marshall Scholarship for a Ph.D (1961) in physics from the University of Cambridge, England, where he was a Research Fellow at Pembroke College and completed his PhD, "Long wavelength X-ray microanalysis" under the supervision of Ellis Cosslett.

Career As a non degree-holding "consultant", Dolby played a key role in the effort that led Ampex to unveil their prototype Quadruplex videotape recorder in April 1956 which soon entered production. After Cambridge, Dolby acted as a technical advisor to the United Nations in India until 1965, when he returned to England, where he founded Dolby Laboratories in London with a staff of four. In that same year, 1965, he invented the Dolby noise-reduction system, a form of audio signal processing for analog tape recorders. His first U.S. patent application was made in 1969, four years later. The system was first used by Decca Records in the UK. The Dolby B consumer noise-reduction system works by compressing (boosting) low-level high-frequency sounds during recording and expanding (decreasing) them symmetrically during playback, which also decreases inherent tape noise. This reduces the audible level of tape hiss. The professional Type A system operates on four different frequency bands, and the final SR system on ten. After his pioneering work with audiotape noise reduction, Dolby sought to improve film sound. As Dolby Laboratories' corporate history explains:

Upon investigation, Dolby found that many of the limitations in optical sound stemmed directly from its significantly high background noise. To filter this noise, the high-frequency response of theatre playback systems was deliberately curtailed… To make matters worse, to increase dialogue intelligibility over such systems, sound mixers were recording soundtracks with so much high-frequency pre-emphasis that high distortion resulted. The first film with Dolby sound was A Clockwork Orange (1971), which used Dolby noise reduction on all pre-mixes and masters, but a conventional optical sound track on release prints. Callan (1974) was the first film with a Dolby-encoded optical soundtrack. The first true LCRS (Left-Center-Right-Surround) soundtrack was encoded on the movie A Star Is Born in 1976. In less than ten years, 6,000 cinemas worldwide were equipped to use Dolby Stereo sound. Dolby then developed a digital surround sound compression scheme for the cinema. Dolby Stereo Digital (now simply called Dolby Digital) was first featured on the 1992 film Batman Returns. Dolby Digital is now found in the HDTV (ATSC) standard of the United States, DVD players, and many satellite-TV and cable-TV receivers. Dolby was a Fellow and past president of the Audio Engineering Society.

Death and legacy Dolby died of leukemia on September 12, 2013, at his home in San Francisco at the age of 80. Dolby was survived by his wife Dagmar, two sons, Tom and David, and four grandchildren. Kevin Yeaman, president and chief executive of Dolby Laboratories, said, "Today we lost a friend, mentor and true visionary." Neil Portnow, president of the National Academy of Recording Arts and Sciences, said Dolby had "changed the way we listen to music and movies for nearly 50 years" and that Dolby's "technologies have become an essential part of the creative process for recording artists and filmmakers, ensuring his remarkable legacy for generations to come." In his will, Dolby bequeathed £35 million to Pembroke College, Cambridge, reportedly the largest single donation received by any college in the university's history. In December 2017 it was announced that his family had donated a further £85m from his estate to Cambridge University's Cavendish Laboratory which funded a physics professorship and the building of the Ray Dolby Centre. Funding for the new building was supplemented with £75m from the UK government, and it was completed in 2024; its facilities include lecture halls and 173 laboratories. In 2022, the Dolby Family Fund for Excellence in Physics was expected to fund further academic posts and PhD studentships, as well as an annual symposium.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Ray Dolby

Start with the simplest possible case. Write down what Ray Dolby claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Ray Dolby before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Ray Dolby ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Ray Dolby

In research: Ray Dolby appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Ray Dolby in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Ray Dolby is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1933 births, 2013 deaths, 20th-century American businesspeople, so understanding it makes those chapters shorter.
In everyday life: Look for Ray Dolby outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Ray Dolby in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Ray Dolby means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Ray Dolby out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Ray Dolby in simple terms?

Why does Ray Dolby matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Ray Dolby?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Ray Dolby.