The fascinating story of the man who invented stereo (and pioneered TV and radar too)

Honoured at the famous Abbey Road Studios, Alan Dower Blumlein pioneered all kinds of technologies before his untimely death during a top-secret wartime mission.

Richard Trenholm Former Movie and TV Senior Editor
Richard Trenholm was CNET's film and TV editor, covering the big screen, small screen and streaming. A member of the Film Critic's Circle, he's covered technology and culture from London's tech scene to Europe's refugee camps to the Sundance film festival.
Expertise Films, TV, Movies, Television, Technology
Richard Trenholm
4 min read

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When you're rocking out to your favourite music, or surround sound has slapped you in the heart of your favourite movie, you know how important stereo sound is. And it's all thanks to Alan Blumlein, the 20th-century pioneer of various technologies who was inspired to invent stereo after a trip to the movies.

Blumlein was honoured Wednesday by the Institute of Electrical and Electronics Engineers and record company EMI, where he worked for much of his life. Blumlein's son Simon and grandson, also named Alan, attended the unveiling of the plaque at Abbey Road Studios in St John's Wood, North London, where Blumlein oversaw one of the earliest stereo recordings.

Alan Dower Blumlein, the man who invented stereo. EMI Group Archive Trust

"This is very, very special, because it's for the engineers," Blumlein's grandson Alan told CNET.

Alan Dower Blumlein's stereo breakthrough began in 1931 when he visited the cinema with his wife Doreen. Frustrated that the sound from a single speaker didn't match up with the actors and action on the screen, he told his wife he had a better idea. That same year, Blumlein filed a patent including a whopping 70 ideas related to stereo, some of which are still in use today.

The first stereo discs were cut in 1933. And in 1934, Blumlein recorded in stereo the London Philharmonic Orchestra, conducted by Sir Thomas Beecham, as it performed Mozart's Jupiter Symphony, at the recording facility now known as Abbey Road Studios. It's a fitting location, then, for Blumlein's contribution to audio technology to be commemorated.

The famous recording facility on Abbey Road was opened in 1931 by the Gramophone Company, a predecessor of British music company EMI. Known as EMI Studios until 1970, the studios are synonymous with the Beatles thanks to their 1969 "Abbey Road" album and its iconic cover, but musical powerhouses from Sir Edward Elgar to Pink Floyd, Muse and Lady Gaga have recorded there.

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Fun fact: EMI Studios was only actually dubbed Abbey Road Studios in 1970 -- the building was named after the Beatles album, and not the other way round.

'An incredible mind'

Alan Dower Blumlein was born in London on 29 June 1903 to German-Jewish parents. "Alan wasn't very good at school," says his grandson Alan. "He was a poor reader and a poor writer, but he loved trains and cranes." At the age of 7, Blumlein presented his father with an invoice for repairing the doorbell, an early outing in a glittering career as an electrical engineer that saw him file 121 patents in the space of 13 years and create breakthroughs in a wide range of fields.

The plaque at Abbey Road honouring Alan Blumlein. IEEE

Blumlein's early work included measuring the amplitude and frequency response of human ears, and in the 1920s he invented and patented a number of advances in telephone equipment. After moving into recording technology, he developed a new method for cutting wax master discs that gave better sound quality when making records. He improved amplifiers, and developed moving-coil microphones used in EMI recording studios and in the BBC's Alexandra Palace radio studio.

In between, he relaxed at the pictures, and even there his mind was working. "He had an incredible mind, but I think it was probably quite cluttered," says the younger Alan. "So he and his wife went to the cinema and the ballet as a form of relief -- but even while he was relaxing, he was thinking he couldn't understand why the sound didn't follow the actor, and he thought he could fix that."

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Blumlein's idea for what he called "binaural sound" covered the whole process, from recording sound to reproducing it for the listener. He conceived the configuration of an orthogonal pair of velocity microphones, which became known as a Blumlein Pair. He also developed a "shuffling" circuit that processed the recording to preserve the direction of the sound.

At the other end, reproducing the sound involved recording the two orthogonal channels in a single groove of a record, cut by a special stereo disc-cutting head. A hybrid transformer then mixed the directional signals for playback.

The first film to utilise stereo sound was "Trains at Hayes Station", shot from a window in the EMI offices in Hayes, West London. Here's a clip, in all its crackly black-and-white 1930s glory:

From 1933 he was assigned to work on technology for television, then in its relative infancy. Innovations attributed to Blumlein include resonant flyback scanning, black-level clamping and the slot antenna. He also had a hand in the development of the 405-line Marconi-EMI system created for the television service from Alexandra Palace.

Like many engineers and scientists, Blumlein's work was interrupted by the second world war. The EMI team was seconded in secret to assist the war effort by using their sonic know-how in early radar systems. Blumlein was a crucial member of a team working on the H2S air-to-surface, used against ground-level targets like U-Boats. The system was only retired after the Falklands in the early 1980s.

Sadly, Blumlein did not live to see the lasting impact his many innovations had. He was killed on 7 June 1942, when the Halifax bomber he was flying in crashed during a trial of the H2S radar system. He was 38.

Today, Blumlein's innovations are still in use. "The engineers at Abbey Road and other studios still use my grandfather's recording technique, the Blumlein pair," his grandson says. "And every single day you see people post pictures online of themselves at home -- amateur drummers, for example -- placing microphones in a Blumlein pair configuration.

"His passion was to conceptualise improvements... his vision was that he wanted to make sure the listener had the best experience."