​The Man Who Invented Stereo

Alan Blumlein was honoured today for his invention of stereophonic sound at Abbey Road Studios.

London's Abbey Road Studios is best known as the recording home of the Beatles, but an event held at the iconic building today honoured a man who worked at the studio before John, Paul, George, and Ringo were born—and who had more impact on the music industry than all of the famous four together.

Alan Dower Blumlein, a British electronics engineer born in 1903, invented stereophonic sound—a way of reproducing sound so that it sounds like it's coming from different directions. Some of the ideas he patented back in the early 30s are still used in the stereo we record and listen to today.

Image:  EMI Group Archive Trust

Blumlein was honoured with a Milestone plaque from the Institute of Electrical and Electronic Engineers (IEEE) at Abbey Road, where he worked for music recording company EMI.

The story goes, as Blumlein's son Simon Blumlein recounted at the presentation, that the inventor was at the movies with his wife when he turned to her and suggested that a blind person would never know where the characters were onscreen, as all the sound came from one direction and one speaker set. But he had a solution. He called it "binaural sound," which we now know as stereo.

In 1934, he recorded  Mozart's Jupite​r Symphony with the London Philharmonic at Abbey Road Studios in stereo. Blumlein made the world's first stereo film—the test film Trains at Hayes—in 1935.

Blumlein's work included inventions needed for recording, processing and playing sound in stereo and he had around 70 patents to his name.

Dedicating the plaque, IEEE President Howard Michel explained that his work included "a 'shuffling' circuit to preserve directional sound, an orthogonal 'Blumlein Pair' of velocity microphones, recording of two orthogonal channels in a single groove, stereo disc-cutting head, and hybrid transformers to mix directional signals."

Some of these inventions were on show from the EMI archive, including a "binaural" microphone arrangement known as the  Blumlei​n Pair. The pair of microphones are positioned at a right-angle to pick up sound separately and so give the stereo effect.

Image: Victoria Turk

The two channels on a single groove refers to the cut of grooves in a gramophone record; Blumlein  developed a ​way to have two cuts read at the same time, to play back the stereo sound.

"He developed an end-to-end system," Blumlein's grandson, also named Alan, told me at the event. "So it was from the microphones, to how the sound was then processed after the microphones, to the speakers so that we actually understand left and right sound out of speakers, and also to the cutting of vinyl records—or shellac at the time."

But Blumlein's invention wouldn't be fully appreciated until decades later; the Beatles' first recordings in the 1960s, for instance, were still monophonic. I asked audio engineer Robert Alexander, who wrote a  biograp​hy of Blumlein, what the impact of his invention of stereo was.

"At the time, in the 1930s, very very minor," he said. "Because most people in the 1930s could hardly afford one loudspeaker, much less two. So EMI, who were responsible for the technology, shelved it." It was rediscovered in 1956.

Given his invention of a technology most of us now appreciate every day, it seems surprising that the inventor is not so well-known outside of audio geek circles.

"Although my grandfather, Alan Dower Blumlein, is revered in the audio world in particular, there's probably not much recognition of his work," Alan Blumlein said. "It's partly because he died in 1942, of course the war effort was underway—and actually the news of his death was restricted, because at that point he was working on airborne radar."

Indeed, while Blumlein's invention of stereo was the main focus of today, the inventor also worked in telecommunications, television, other aspects of sound recording, and the radar that went on to play a role in the war. He died in 1942 when a bomber plane used in a trial of the radar crashed.

Perhaps now the commemoration plaque will remind artists as they enter the famous recording studios that it's thanks to one man that any of them can record their work in stereophonic sound.