Milestones:Improvements in and relating to Sound-transmission, Sound-recording and Sound-reproduction systems by Alan Dower Blumlein

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Alan Dower Blumlein filed a patent for a two-channel audio system called “stereo” on 14 December 1931. It included a "shuffling" circuit to preserve directional sound, an orthogonal “Blumlein Pair” of velocity microphones, the recording of two orthogonal channels in a single groove, stereo disc-cutting head, and hybrid transformer to mix directional signals. Blumlein brought his equipment to Abbey Road Studios in 1934 and recorded the London Philharmonic Orchestra.

Street address(es) and GPS coordinates of the Milestone Plaque Sites

51.5321445, -0.1779186, {{{address}}}

Details of the physical location of the plaque

Studios are working studios having been established in 1931. Abbey Road was the site of where on January 19th 1934, Alan Blumlein used his Stereo recording equipment to record Sir Thomas Beecham conducting the London Philharmonic Orchestra playing Mozart's Jupiter Symphony.

There is one existing plaque on the front of Abbey Road which is dedicated to Sir Edward Elgar who officially opened the Abbey Road Studios on November 12th 1931

How the intended plaque site is protected/secured

The plaque will be firmly secured to the outside of the building. Visitors can view the plaque from Abbey Road and will not need access to the studios.

Historical significance of the work

The historical significance of this work is that Alan Blumlein developed a single track, 2 channel recording system. Although he used the available methods of Hill and Dale & Lateral Cutting to achieve groves at 90 degrees to each other, he specified that 45/ 45 cutting system would have significant advantages. Within his patent, he went into great detail about the technology involved with the problems associated with sound reproduction and interpretation by the human brain.

Features that set this work apart from similar achievements

Single grove two channel recording method

Future development in the use of sound recording and reproduction for film was also covered in the patent.

Significant references

(1) Patent number 394,325 - Improvements in and relating to Sound-transmission, Sound recording and Sound-reproducing Systems

(2)IEEE Global History Network Article -

(3)The Inventor of Stereo: The Life and Works of Alan Dower Blumlein By Robert Charles Alexander. Focal Press, 1999. ISBN 0-240-51628-1

(4)The Life and Times of A. D. Blumlein Rusell Burns. IEE History of Technology Series, 2000 ISSN 0953-5683

(5) Alan Dower Blumlein Wikipedia -

(6) EMI Archive Trust - Alan Blumlein and the Invention of Stereo

(7) The New Stereo Sound Book Everest and Streicher TAB Books (prints patent 394,325 with comments)

Supporting materials

See above