Written by our Staff Editor
On December 14th 1931, EMI engineer Alan Dower Blumlein filed a patent for a two-channel audio system, for what we now know as ‘Stereo’.
Alan Dower Blumlein (1903 – 1942) was an English electronics engineer, notable for his many inventions in telecommunications, sound recording, stereophonic sound, television and radar. He received 128 patents and was considered as one of the most significant engineers and inventors of his time.
In 1931, Blumlein invented what he called “binaural sound”, but now known as stereophonic sound. His earliest notes on the subject are dated 25 September 1931, and his patent had the title “Improvements in and relating to Sound-transmission, Sound-recording and Sound-reproducing Systems”. The application was dated 14 December 1931 as UK patent number 394,325. The patent covered numerous ideas in stereo, some of which are used today.
By 1929 he was an engineer at Columbia Graphophone, and was appointed to work on monophonic recording, primarily to circumvent the Western Electric patents on electrical recording. Columbia Graphophone 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 ‘stereo’. EMI was not quite sure what to do with Blumlein’s stereo 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.
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.