Alan Dower Blumlein
Alan Dower Blumlein
Born: 29 June 1903
Died: 07 June 1942
Blumlein was one of the most prolific inventors of the first half of the twentieth century. He earned one hundred and twenty eight patents in electronic and audio engineering before he died at the age of thirty-nine. By 1929 he was an engineer at Columbia Graphophone, which in 1931 merged with The Gramophone Company to become Electrical and Musical Industries (EMI).
At EMI, Blumlein helped develop many advanced technologies used to record sound, including an important type of microphone called the “moving coil” microphone. In December of 1931, Blumlein patented a remarkable new system of recording that he called “binaural sound.” Binaural sound was similar to what we would call “stereo” today. It used two microphones, recorded two separate recordings, and reproduced them from two separate loudspeakers. It was intended to duplicate the way we hear sounds through our two separate ears.
EMI was not quite sure what to do with Blumlein’s invention and put it aside for a few years. However, they had foresight, and in 1931, when the company opened a new studio at Abbey Road in London, Blumlein’s electrical recording system was installed. EMI made the first few stereo recordings and films in the 1930s and then shelved the technology.
Blumlein spent the mid-1930s developing electrical circuitry for an electronic method of picture transmission for television. He was the leader of the team that convinced the BBC in 1937 to opt for electrical rather than mechanical television. He next turned his attention to sound detection systems to detect aircraft. Blumlein incorporated the binaural sound system into aircraft sound detectors and displayed the results visually using a cathode ray tube. This system could offer obvious military benefits for a nation at war. But EMI was initially shut out of British radar research because the company was not perceived as a producer of defense equipment. However, Blumlein brought EMI into radar research by helping develop an airborne interception system that could detect aircraft by night. He was part of a team testing the H2S system, which could locate and detect targets from the air regardless of weather conditions. Tragically, Blumlein and many of the other members of the scientific development team were killed in a 1942 plane crash that also destroyed the H2S system prototype. One Air Chief Marshall called his death “a catastrophe,” while the Secretary of State for Air called it “a national disaster.” The detection system was completed later in the war by a new research team.
When interest in stereo sound revived in the 1950s, Blumlein’s work was remembered. Around 1957, both RCA and EMI were close to offering a new stereo system based on the existing long playing (LP) record, which had been introduced in 1949. The two companies teamed up and shared information so their products would be compatible. The next year, in 1958, the first stereo records appeared.
1) The Inventor of Stereo: The Life and Works of Alan Dower Blumlein
Robert Charles Alexander. Focal Press, 1999.
2)The Life and Times of A. D. Blumlein.
Rusell Burns. IEE History of Technology Series, 2000.