The story of binaural audio - 'stereo'


Where did the idea for 'stereo' sound come from ?

One day in 1931, Alan Blumlein took his wife to be, Doreen, to the cinema and said to her during the film: "Do you realise the sound only comes from one person?" Doreen, by her own admission not a technical person, replied, "Oh does it?" and he said, "Yes. And I've got a way to make it follow the person".

Alan Blumlein had just tried to describe his first thoughts about the system he would always call 'Binaural Sound', but which we have come to know better as Stereophonic or 'Stereo' Sound.

Blumlein explained to Doreen that, if she could imagine being blind, and sitting in the cinema, she would be able to point out exactly where the person was on the screen with his system. This, of course, was what he was trying to achieve, not this 'terrible effect' where the sound comes from one side of the screen when the actor was at the other side.

Sir Isaac Shoenberg (1888-1963), Managing Director at EMI, Hayes, brilliant visionary and Alan Blumlein's friend and mentor

Sir Isaac Shoenberg (1888-1963)

Blumlein's mentor at EMI was Isaac Shoenberg. It was Shoenberg who allowed Blumlein's genius to flourish by giving him a free hand while working on binaural sound and later television and radar

The men who made binaural sound a reality

Alan Blumlein was an incredibly modest man, and would be the first to credit the work carried out by his colleagues. While it was Blumlein's genius which came up with the concept of binaural, it was his colleagues, and their work at EMI, which made the sound experiments possible.

Herbert Holman who, with Blumlein, played a vital role in the development of the first recording and reproduction systems

Key among these men was Herbert Holman (above) and Henry 'Ham' Clark. It was Holman and Clark had been working on a recording and reproduction system for records at Columbia since 1927.

The Columbia recorder/reproducer which paved the way for Blumlein's later experiments with stereo or 'binaural' sound

When, in 1929, Isaac Shoenberg brought Alan Blumlein to Columbia, it was with the specific intention of improving this record production system.

Together the three men managed to produce and electromechanical system which overcame the patents held by Bell Labs, which forced Columbia, and anybody else for that matter, into paying a royalty on every record they produced.

The Blumlein/Holman system not only overcame the royalty problem, but vastly improved the quality of record reproduction, quality which survived late into the 20th century.

Herbert Holman also put his initial to one half of the 'HB' microphone series (see diagram below). These revolutionary microphones were not only used to record all the later binaural experiments, but were so good, that the BBC adopted them for use at Alexandra Palace for television recording well into the 1950s.

The 'HB1B' Microphone, naned after 'Holman' and 'Blumlein'

Herbert Holman can be seen taking part in the 'Walking & Talking' binaural film (left) in front of Alan Blumlein on the stage.

Henry Arthur Maish Clark or 'HAM' as he was always known to his colleagues, another of Blumlein's co-inventors in the recorder/reproducer

Henry Arthur Maish Clark, or 'ham' as he was always known - not only for his initials, but also because he was an avid ham radio enthusiast.

The Binaural Sound and Film Experiments 1931-1935

On 14 December 1931, Alan Blumlein applied for his famous patent, No.394,325, Binaural Sound, in which he describes in great detail, an electronic method of reproducing sound from two microphones and two loudspeakers. He called this system 'Binaural' from the human factor of having two ears by which we hear sound.

Because this patent was so far ahead of its time, it would be another 20 years before it was fully appreciated, long after Blumlein's tragic early death in 1942. Of course, today, we know Binaural as 'Stereo'.

In his patent, Blumlein goes on to describe a method of reproducing sound for cinema in which the sound would 'follow' the actor as he/she moves across the screen. This method was eventually adopted with the first major motion picture to benefit being 'Ben Hur' in 1959.

However, long before the concept of Ben Hur had been drawn up, Blumlein and his team had experimented with stereo sound film cameras. During the summer of 1935, they spent many weeks on location in and around Hayes, filming all manner of subject material.

Of these films, all of which survive, perhaps the most famous are 'Trains at Hayes Station', in which a steam locomotive was recorded as it left the station, the familiar puff, puff, of the train moving from right to left in the loudspeakers as the train moved away from the platform.

During the summer of 1935, the binaural film team took several films outside to obtain the stereo effect. Here they are filming trains departing from Hayes station to achieve the 'Doppler' effect

A scene from 'Trains at Hayes Station', July 1935

In one short piece of footage, which has become known as 'Walking & Talking', Blumlein himself appears briefly, walking across a stage at EMI, counting from one to seven. As he walks his voice quite distinctly 'moves' from the left loudspeaker to the right, following his motion.

One of the most important moments in film history. Known as 'Walking & Talking' this is the moment when Blumlein (left) and Holman, with others, walk from left to right  speaking numbers and talking to produce the worlds first stereo effect captured on celluloid

'Walking & Talking', with Alan Blumlein on the left

Despite the work proving very successful, Isaac Shoenberg and EMI were concerned that the Binaural experiments would have little commercial value. It was a time when most people could barely afford one loudspeaker, much less two. There was also the pressing need for Blumlein to concentrate on the high definition television project where his electronic circuitry genius was much needed.

By the Autumn of 1935, the team felt confident enough in their experiments to produce a small play filmed entirely with the Binaural film camera. Filmed in the auditorium at EMI, Hayes with the help of the amateur dramatic society made up from company employees, the results were encouraging. But the experiments were shelved soon after in order to complete the television work.

Filmed in stereo in the summer of 1935, this 'Playlet' was shot at the auditorium at EMI, Hayes with actors from the amateur dramatic society from within the company

'The Playlet', filmed in the Auditorium at EMI, Hayes

It was intended for Blumlein to return to it later, but following his work completing the television system, was soon followed, and Blumlein found his attention drawn to radar.

Many years would pass before enthusiasts at EMI would resurrect Binaural sound. Only then did they discover that much of the modern surround sound system which we employ today in cinema and home entertainment, was laid down precisely by Alan Blumlein nearly 70 years ago.


You can now read the whole of chapter three of my book 'The Audio Patents'

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