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

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Docket #:2013-27

This Proposal has been approved, and is now a Milestone

Is the achievement you are proposing more than 25 years old? Yes

Is the achievement you are proposing within IEEE’s fields of interest? (e.g. “the theory and practice of electrical, electronics, communications and computer engineering, as well as computer science, the allied branches of engineering and the related arts and sciences” – from the IEEE Constitution) Yes

Did the achievement provide a meaningful benefit for humanity? Yes

Was it of at least regional importance? Yes

Has an IEEE Organizational Unit agreed to pay for the milestone plaque(s)? Yes

Has an IEEE Organizational Unit agreed to arrange the dedication ceremony? Yes

Has the IEEE Section in which the milestone is located agreed to take responsibility for the plaque after it is dedicated? Yes

Has the owner of the site agreed to have it designated as an Electrical Engineering Milestone? Yes

Year or range of years in which the achievement occurred:

1931 - 1934

Title of the proposed milestone:

Invention of Stereo Sound Reproduction, 1931

Plaque citation summarizing the achievement and its significance:

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.

In what IEEE section(s) does it reside?


IEEE Organizational Unit(s) which have agreed to sponsor the Milestone:

IEEE Organizational Unit(s) paying for milestone plaque(s):

Unit: IEEE UK&RI Section
Senior Officer Name: Senior officer name masked to public

IEEE Organizational Unit(s) arranging the dedication ceremony:

Unit: IEEE UK&RI Section
Senior Officer Name: Senior officer name masked to public

IEEE section(s) monitoring the plaque(s):

IEEE Section: IEEE UK&RI Section
IEEE Section Chair name: Section chair name masked to public

Milestone proposer(s):

Proposer name: Proposer's name masked to public
Proposer email: Proposer's email masked to public

Proposer name: Proposer's name masked to public
Proposer email: Proposer's email masked to public

Please note: your email address and contact information will be masked on the website for privacy reasons. Only IEEE History Center Staff will be able to view the email address.

Street address(es) and GPS coordinates of the intended milestone plaque site(s):

Abbey Road Studios, 3 Abbey Road, St. John's Wood, London NW8 9AY GPS coordinates are N 51 31.925' W 000 10.637'

Describe briefly the intended site(s) of the milestone plaque(s). The intended site(s) must have a direct connection with the achievement (e.g. where developed, invented, tested, demonstrated, installed, or operated, etc.). A museum where a device or example of the technology is displayed, or the university where the inventor studied, are not, in themselves, sufficient connection for a milestone plaque.

Please give the address(es) of the plaque site(s) (GPS coordinates if you have them). Also please give the details of the mounting, i.e. on the outside of the building, in the ground floor entrance hall, on a plinth on the grounds, etc. If visitors to the plaque site will need to go through security, or make an appointment, please give the contact information visitors will need. Abbey Road 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

Are the original buildings extant?

Yes -EMI research Building at Hayes Middlesex is Extant- the testing of Stereo cutting and recording equipment by Alan Blumlein was in an existing studio at Abbey Road

Details of the plaque mounting:

Outside of building on front face above or alongside the main entrance to the Abbey Road Studios.

How is the site protected/secured, and in what ways is it accessible to the public?

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.

Who is the present owner of the site(s)?

Abbey Road Studios

What is the historical significance of the work (its technological, scientific, or social importance)?

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.

What obstacles (technical, political, geographic) needed to be overcome?

Obstacles to be overcome included the fact that at the time of going to patent, shellac discs were used for commercial reproduction of recordings and better materials had to be developed. Shellac had limitations due to its use as a workable material and its poor reproductive qualities meaning that Shellac discs would not permit the playback of high quality sound.

Electrical reproduction in the home was often opposed as to the amount of equipment required.

EMI had a focus on the development of television

What features 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.

References to establish the dates, location, and importance of the achievement: Minimum of five (5), but as many as needed to support the milestone, such as patents, contemporary newspaper articles, journal articles, or citations to pages in scholarly books. You must supply the texts or excerpts themselves, not just the references. At least one of the references must be from a scholarly book or journal article.

(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 (supported formats: GIF, JPEG, PNG, PDF, DOC): All supporting materials must be in English, or if not in English, accompanied by an English translation. You must supply the texts or excerpts themselves, not just the references. For documents that are copyright-encumbered, or which you do not have rights to post, email the documents themselves to Please see the Milestone Program Guidelines for more information.

EMI Archive Trust Illustrations from the Stereo patent

Please email a jpeg or PDF a letter in English, or with English translation, from the site owner(s) giving permission to place IEEE milestone plaque on the property, and a letter (or forwarded email) from the appropriate Section Chair supporting the Milestone application to with the subject line "Attention: Milestone Administrator" .

2013-27 Stereo UKRI Section support letter 002.jpg