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Alan Dower Blumlein (29 June 1903 – 7 June 1942) was an English
electronics The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons using electronic devices. Electronics uses active devices to control electron flow by amplification ...
engineer, notable for his many inventions in telecommunications,
sound recording Sound recording and reproduction is the electrical, mechanical, electronic, or digital inscription and re-creation of sound waves, such as spoken voice, singing, instrumental music, or sound effects. The two main classes of sound recording te ...
,
stereophonic sound Stereophonic sound, or more commonly stereo, is a method of sound reproduction that recreates a multi-directional, 3-dimensional audible perspective. This is usually achieved by using two independent audio channels through a configuration ...
, television and radar. He received 128 patents and was considered one of the most significant engineers and inventors of his time. He died during
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
on 7 June 1942, aged 38, during the secret trial of an H2S airborne radar system then under development, when all on board the
Halifax bomber The Handley Page Halifax is a British Royal Air Force (RAF) four-engined heavy bomber of the World War II, Second World War. It was developed by Handley Page to the same specification as the contemporary twin-engine Avro Manchester. The Halifa ...
in which he was flying were killed when it
crashed "Crashed" is the third U.S. rock Single (music), single, (the fifth overall), from the band Daughtry (band), Daughtry's debut album. It was released only to U.S. rock stations on September 5, 2007. Upon its release the song got adds at those stat ...
at
Welsh Bicknor Welsh Bicknor ( cy, Llangystennin Garth Brenni) is an area in the far south of the English county of Herefordshire. Despite its name, it is not now in Wales, but it was historically a detached parish (exclave) of the county of Monmouthshire. It ...
in Herefordshire.


Early life

Alan Dower Blumlein was born on 29 June 1903 in
Hampstead Hampstead () is an area in London, which lies northwest of Charing Cross, and extends from Watling Street, the A5 road (Roman Watling Street) to Hampstead Heath, a large, hilly expanse of parkland. The area forms the northwest part of the Lon ...
, London. His father, Semmy Blumlein, was a German-born naturalised British subject. Semmy was the son of Joseph Blumlein, a German of
Jewish Jews ( he, יְהוּדִים, , ) or Jewish people are an ethnoreligious group and nation originating from the Israelites Israelite origins and kingdom: "The first act in the long drama of Jewish history is the age of the Israelites""The ...
descent, and Philippine Hellmann, a French woman of German descent.Semmy Blumlein's father, Joseph B. Blumlein was Jewish, ''see Burns, p. 2'' Alan's mother, Jessie Dower, was Scottish, daughter of William Dower (born 1837) who went to South Africa for the
London Missionary Society The London Missionary Society was an interdenominational evangelical missionary society formed in England in 1795 at the instigation of Welsh Congregationalist minister Edward Williams. It was largely Reformed in outlook, with Congregational miss ...
. Alan was christened as a
Presbyterian Presbyterianism is a part of the Reformed tradition within Protestantism that broke from the Roman Catholic Church in Scotland by John Knox, who was a priest at St. Giles Cathedral (Church of Scotland). Presbyterian churches derive their nam ...
; he later married in a
Church of England The Church of England (C of E) is the established Christian church in England and the mother church of the international Anglican Communion. It traces its history to the Christian church recorded as existing in the Roman province of Britain ...
parish church. Alan Blumlein's future career seemed to have been determined by the age of seven, when he presented his father with an invoice for repairing the doorbell, signed "Alan Blumlein, Electrical Engineer" (with "paid" scrawled in pencil). His sister claimed that he could not read proficiently until he was 12. He replied "no, but I knew a lot of quadratic equations!" After leaving Highgate School in 1921, he studied at
City and Guilds College The Faculty of Engineering is the engineering school of Imperial College London, and one of the three main faculties the college. It was formed in 2001 from the former City and Guilds College and the Royal School of Mines—two of the three o ...
(part of
Imperial College Imperial College London (legally Imperial College of Science, Technology and Medicine) is a public research university in London, United Kingdom. Its history began with Prince Albert, consort of Queen Victoria, who developed his vision for a cu ...
). He won a Governors' scholarship and joined the second year of the course. He graduated with a
First-Class Honours The British undergraduate degree classification system is a grading structure for undergraduate degrees or bachelor's degrees and integrated master's degrees in the United Kingdom. The system has been applied (sometimes with significant variati ...
BSc A Bachelor of Science (BS, BSc, SB, or ScB; from the Latin ') is a bachelor's degree awarded for programs that generally last three to five years. The first university to admit a student to the degree of Bachelor of Science was the University ...
two years later. In mid-1930, Blumlein met Doreen Lane, a preparatory school teacher five years his junior. After two-and-a-half years of courtship the two were married in 1933. Lane was warned by acquaintances before the wedding that, "There was a joke amongst some of his friends, they used to call it 'Blumlein-itis' or 'First Class Mind'. It seems that he didn't want to know anyone who didn't have a first class mind." Recording engineer Joseph B. Kaye, known as J. B. Kaye, who was Blumlein's closest friend and best man at the wedding, thought the couple were well matched.


Career and inventions


Telecommunications

In 1924 Blumlein started his first job at
International Western Electric Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by mul ...
, a division of the
Western Electric Company The Western Electric Company was an American electrical engineering and manufacturing company officially founded in 1869. A wholly owned subsidiary of American Telephone & Telegraph for most of its lifespan, it served as the primary equipment m ...
. The company subsequently became International Standard Electric Corporation and then, later on,
Standard Telephones and Cables Standard Telephones and Cables Ltd (later STC plc) was a British manufacturer of telephone, telegraph, radio, telecommunications, and related equipment. During its history, STC invented and developed several groundbreaking new technologies incl ...
(STC). During his time there, he measured the
amplitude The amplitude of a periodic variable is a measure of its change in a single period (such as time or spatial period). The amplitude of a non-periodic signal is its magnitude compared with a reference value. There are various definitions of amplit ...
/
frequency response In signal processing and electronics, the frequency response of a system is the quantitative measure of the magnitude and phase of the output as a function of input frequency. The frequency response is widely used in the design and analysis of sy ...
of human ears, and used the results to design the first
weighting The process of weighting involves emphasizing the contribution of particular aspects of a phenomenon (or of a set of data) over others to an outcome or result; thereby highlighting those aspects in comparison to others in the analysis. That i ...
networks. In 1924 he published (with Professor Edward Mallett) the first of his only two IEE papers, on high-frequency resistance measurement. This won him the IEE's Premium award for innovation. The following year he wrote (with Norman Kipping) a series of seven articles for
Wireless World ''Electronics World'' (''Wireless World'', founded in 1913, and in September 1984 renamed ''Electronics & Wireless World'') is a technical magazine in electronics and RF engineering aimed at professional design engineers. It is produced monthly in ...
. In 1925 and 1926, Blumlein and John Percy Johns designed an improved form of loading coil which reduced loss and
crosstalk In electronics, crosstalk is any phenomenon by which a signal transmitted on one circuit or channel of a transmission system creates an undesired effect in another circuit or channel. Crosstalk is usually caused by undesired capacitive, induc ...
in long-distance telephone lines. These were used until the end of the analogue telephony era. The same duo also invented an improved form of AC measurement
bridge A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually somethi ...
which became known as the '' Blumlein Bridge'' and subsequently the ''
transformer ratio arm bridge The transformer ratio arm bridge or TRA bridge is a type of bridge circuit used for measuring electronic components, using a.c. It can be designed to work in terms of either impedance or admittance. It can be used on resistors, capacitors and ind ...
''. These two inventions were the basis for Blumlein's first two patents. His inventions while working at STC resulted in another five patents, which were not awarded until after he left the company in 1929.


Sound recording

In 1929 Blumlein resigned from STC and joined the
Columbia Graphophone Company Columbia Graphophone Co. Ltd. was one of the earliest phonograph, gramophone companies in the United Kingdom. Founded in 1917 as an offshoot of the American Columbia Records, Columbia Phonograph Company, it became an independent British-owned ...
, where he reported directly to general manager
Isaac Shoenberg Sir Isaac Shoenberg (1 March 1880 – 25 January 1963) was a British electronic engineer born in Belarus who was best known for his role in the history of television. He was the head of the EMI research team that developed the 405-line (Marconi-EM ...
. His first project was to find a method of disc cutting that circumvented a Bell patent in the ''Western Electric moving-iron cutting head'' then used, and on which substantial royalties had to be paid. He invented the moving-coil disc cutting head, which not only got around the patent but offered greatly improved sound quality. He led a small team which developed the concept into a practical cutter. The other principal team members were Herbert Holman and Henry "Ham" Clark. Their work resulted in several patents. Early in 1931, the Columbia Graphophone Company and the
Gramophone Company The Gramophone Company Limited (The Gramophone Co. Ltd.), based in the United Kingdom and founded by Emil Berliner, was one of the early recording companies, the parent organisation for the ''His Master's Voice (HMV)'' label, and the European ...
merged and became
EMI EMI Group Limited (originally an initialism for Electric and Musical Industries, also referred to as EMI Records Ltd. or simply EMI) was a British Transnational corporation, transnational Conglomerate (company), conglomerate founded in March 1 ...
. New joint research laboratories were set up at Hayes and Blumlein was officially transferred there on 1 November the same year. During the early 1930s Blumlein and Herbert Holman developed a series of moving-coil microphones, which were used in EMI recording studios and by the
BBC #REDIRECT BBC #REDIRECT BBC Here i going to introduce about the best teacher of my life b BALAJI sir. He is the precious gift that I got befor 2yrs . How has helped and thought all the concept and made my success in the 10th board exam. ...
...
at
Alexandra Palace Alexandra Palace is a Grade II listed entertainment and sports venue in London, situated between Wood Green and Muswell Hill in the London Borough of Haringey. It is built on the site of Tottenham Wood and the later Tottenham Wood Farm. Origi ...
.


Ultra-linear amplifier

In June 1937, Blumlein patented what is now known as the '' Ultra-Linear'' amplifier (US Patent 2,218,902, dated 5 June 1937). A deceptively simple design, the circuit provided a tap on the primary winding of the output transformer to provide feedback to the second grid, which improved the amplifier's linearity. With the tap placed at the anode end of the primary winding, the tube (valve) is effectively connected as a
triode A triode is an electronic amplifying vacuum tube (or ''valve'' in British English) consisting of three electrodes inside an evacuated glass envelope: a heated filament or cathode, a grid, and a plate (anode). Developed from Lee De Forest's 19 ...
, and if the tap was at the supply end, as a pure
pentode A pentode is an electronic device having five electrodes. The term most commonly applies to a three-grid amplifying vacuum tube or thermionic valve that was invented by Gilles Holst and Bernhard D.H. Tellegen in 1926. The pentode (called a ''tripl ...
. Blumlein discovered that if the tap was placed at a distance 15–20% down from the supply end of the output transformer, the tube or valve would combine the positive features of both the triode and the pentode design.


Long-tailed pair

Blumlein may or may not have invented the
long-tailed pair A differential amplifier is a type of electronic amplifier that amplifies the difference between two input voltages but suppresses any voltage common to the two inputs. It is an analog circuit with two inputs V_\text^- and V_\text^+ and one outpu ...
, but his name is on the first patent (1936). The long-tailed pair is a form of
differential amplifier A differential amplifier is a type of electronic amplifier that amplifies the difference between two input voltages but suppresses any voltage common to the two inputs. It is an analog circuit with two inputs V_\text^- and V_\text^+ and one outpu ...
that has been popular since the days of the
vacuum tube A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied. The type kn ...
(valve). It is now more pervasive than ever, as it is particularly suitable for implementation in
integrated circuit An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...
form, and almost every
operational amplifier An operational amplifier (often op amp or opamp) is a DC-coupled high-gain electronic voltage amplifier with a differential input and, usually, a single-ended output. In this configuration, an op amp produces an output potential (relative to c ...
integrated circuit contains at least one.


Stereophonic sound

In 1931, Blumlein invented what he called "binaural sound", now known as
stereophonic sound Stereophonic sound, or more commonly stereo, is a method of sound reproduction that recreates a multi-directional, 3-dimensional audible perspective. This is usually achieved by using two independent audio channels through a configuration ...
. In early 1931, he and his wife were at the cinema. The sound reproduction systems of the early
talkie A sound film is a motion picture A film also called a movie, motion picture, moving picture, picture, photoplay or (slang) flick is a work of visual art that simulates experiences and otherwise communicates ideas, stories, percep ...
s only had a single set of speakers – the actor might be on one side of the screen, but the voice could come from the other. Blumlein declared to his wife that he had found a way to make the sound follow the actor. Blumlein explained his ideas to Isaac Shoenberg in the late summer of 1931. 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, and was accepted on 14 June 1933 as UK patent number 394,325. The patent covered numerous ideas in stereo, some of which are used today. Some 70 claims include: * A "shuffling" circuit, which aimed to preserve the directional effect when sound from a spaced pair of microphones was reproduced via stereo loudspeakers instead of a pair of headphones * The use of a coincident pair of velocity microphones with their axes at right angles to each other, which is still known as a "
Blumlein Pair Blumlein pair is a stereo recording technique invented by Alan Blumlein for the creation of recordings that, upon replaying through headphones or loudspeakers, recreate the spatial characteristics of the recorded signal. The pair consists of an a ...
" * Recording two channels in the single groove of a record using the two groove walls at right angles to each other and 45 degrees to the vertical * A stereo disc-cutting head * Using hybrid transformers to matrix between left and right signals and sum and difference signals Blumlein's binaural experiments began in early 1933, and the first stereo discs were cut later the same year. Much of the development work on this system for cinematic use was completed by 1935. In Blumlein's short test films (most notably, "Trains at Hayes Station", which lasts 5 minutes 11 seconds, and, "The Walking & Talking Film"), his original intent of having the sound follow the actor was fully realised. In 1934, Blumlein recorded
Mozart Wolfgang Amadeus Mozart (27 January 17565 December 1791), baptised as Joannes Chrysostomus Wolfgangus Theophilus Mozart, was a prolific and influential composer of the Classical period (music), Classical period. Despite his short life, his ra ...
's ''
Jupiter Symphony Wolfgang Amadeus Mozart completed his Symphony No. 41 in C major, K. 551, on 10 August 1788. The longest and last symphony that he composed, it is regarded by many critics as among the greatest symphonies in classical music. The work is nicknam ...
'' conducted by Sir
Thomas Beecham Sir Thomas Beecham, 2nd Baronet, Order of the Companions of Honour, CH (29 April 18798 March 1961) was an English conductor and impresario best known for his association with the London Philharmonic Orchestra, London Philharmonic and the Roya ...
at
Abbey Road Studios Abbey Road Studios (formerly EMI Recording Studios) is a recording studio at 3 Abbey Road, St John's Wood, City of Westminster, London, England. It was established in November 1931 by the Gramophone Company, a predecessor of British music c ...
in London using his vertical-lateral technique.


Television

Television was developed by many individuals and companies throughout the 1920s and 1930s. Blumlein's contributions, as a member of the EMI team, started in earnest in 1933 when his boss, Isaac Shoenberg, assigned him full-time to TV research. His ideas included: *Resonant flyback scanning (the use of a tuned circuit in the creation of a sawtooth deflection waveform). (British Patent No. 400976, application filed April 1932.) *Use of constant-impedance network in power supplies to obtain voltage regulation independent of load frequency, extending down to DC (421546, filed 16 June 1933). *Black-level clamping (422914, filed 11 July 1933 by Blumlein, Browne and Hardwick). This is an improved form of DC restoration, compared to the simple DC restorer (consisting of a capacitor, diode and resistor) which had been patented by Peter Willans three months earlier. *The
slot antenna A slot antenna consists of a metal surface, usually a flat plate, with one or more holes or slots cut out. When the plate is driven as an antenna by an applied radio frequency current, the slot radiates electromagnetic waves in a way similar to a ...
. (515684, filed 7 March 1939.) Blumlein was also largely responsible for the development of the waveform structure used in the
405-line The 405-line monochrome analogue television broadcasting system was the first fully electronic television system to be used in regular broadcasting. The number of television lines influences the image resolution, or quality of the picture. It was ...
Marconi-EMI system – developed for the UK's BBC Television Service at
Alexandra Palace Alexandra Palace is a Grade II listed entertainment and sports venue in London, situated between Wood Green and Muswell Hill in the London Borough of Haringey. It is built on the site of Tottenham Wood and the later Tottenham Wood Farm. Origi ...
, the world's first scheduled ''"high definition"'' (240 lines or better) television service – which was later adopted as the ''CCIR System A''.


H2S radar

Blumlein was so central to the development of the H2S airborne radar system (to aid bomb targeting), that after his death in June 1942, many believed that the project would fail. However it survived and was a factor in shortening the
Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
. Blumlein's role in the project was a closely guarded secret at the time and consequently only a brief announcement of his death was made some two years later, to avoid providing solace to Hitler. His invention of the line type pulse modulator (ref vol 5 of MIT Radiation Laboratory series) was a major contribution to high-powered pulse radars, not just the H2S's system, and continues to be used today.


Death and investigation

Blumlein was killed in the crash of an H2S-equipped
Handley Page Halifax The Handley Page Halifax is a British Royal Air Force (RAF) four-engined heavy bomber of the Second World War. It was developed by Handley Page to the same specification as the contemporary twin-engine Avro Manchester. The Halifax has its or ...
test aircraft while making a test flight for the
Telecommunications Research Establishment The Telecommunications Research Establishment (TRE) was the main United Kingdom research and development organization for radio navigation, radar, infra-red detection for heat seeking missiles, and related work for the Royal Air Force (RAF) d ...
(TRE) on 7 June 1942. During the flight from
RAF Defford Royal Air Force Defford or more simply RAF Defford is a former Royal Air Force station located northwest of Defford, Worcestershire, England. History Second World War At the outbreak of the Second World War, Croome Court and its surrounding ...
, whilst at an altitude of 500 ft (150 meters) the Halifax developed an engine fire which rapidly grew out of control.Alexander (1999), pp.322–339 The aircraft was seen to lose altitude, then rolled inverted and struck the ground. The crash occurred near the village of
Welsh Bicknor Welsh Bicknor ( cy, Llangystennin Garth Brenni) is an area in the far south of the English county of Herefordshire. Despite its name, it is not now in Wales, but it was historically a detached parish (exclave) of the county of Monmouthshire. It ...
in Herefordshire. Two of Blumlein's colleagues, Cecil Oswald Browne and Frank Blythen, also died in the crash. The Halifax was carrying a highly-secret
cavity magnetron The cavity magnetron is a high-power vacuum tube used in early radar systems and currently in microwave ovens and linear particle accelerators. It generates microwaves using the interaction of a stream of electrons with a magnetic field while ...
as part of the H2S test system, and the immediate recovery of the device was essential. A team led by Bernard Lovell arrived at the crash scene the same night, and took the magnetron.
"Then reports of a crash in south Wales began to come in and the rest of that night was just a nightmare. I was driven by the C-in-C of the aerodrome
efford Efford (anciently ''Eppeford, Elforde'', etc.) is an historic manor formerly in the parish of Eggbuckland, Devon, England. Today it has been absorbed by large, mostly post-World War II, eastern suburb of the city of Plymouth. It stands on high ...
a man called King, and winding through these lanes near
Ross-on-Wye Ross-on-Wye ( Welsh: ''Rhosan ar Wy'') is a market town in England, near the border with Wales. It had a population of 10,582 according to the 2011 census, estimated at 11,309 in 2019. It lies in south-eastern Herefordshire, on the River Wye ...
searching for this wreckage, and then the field with the burnt-out Halifax, and of course it was wartime, there was no time for emotions, our first duties were to search for the precious highly-secret equipment, and collect the bits-and-pieces of it." – Bernard Lovell.
After the RAF investigative board completed its report on the Halifax crash on 1 July 1942, it was distributed to a restricted list of approved recipients, but not publicly divulged. In the interests of wartime secrecy, the announcement of Blumlein's death was not made for another three years. The investigative board, headed by AIB Chief Inspector Vernon Brown – who later also investigated the post-war '' Star Tiger'' and '' Star Ariel'' disappearances – and assisted by
Rolls-Royce Rolls-Royce (always hyphenated) may refer to: * Rolls-Royce Limited, a British manufacturer of cars and later aero engines, founded in 1906, now defunct Automobiles * Rolls-Royce Motor Cars, the current car manufacturing company incorporated in ...
, who had made the Halifax's
Merlin Merlin ( cy, Myrddin, kw, Marzhin, br, Merzhin) is a mythical figure prominently featured in the legend of King Arthur and best known as a mage, with several other main roles. His usual depiction, based on an amalgamation of historic and le ...
engines, found that the crash was caused by engine fire, attributed to the unscrewing of a
tappet A tappet is most commonly a component in an internal combustion engine which converts the rotating motion of the camshaft into linear motion of the valves, either directly or indirectly. An earlier use of the term was for part of the valve gear ...
nut on the starboard outer engine, which had been improperly tightened by an RAF engine fitter while inspecting the engine some three hours prior to the crash. During the flight the loosened nut caused increasingly excessive valve clearance eventually allowing collision of the valve head with the rising piston fracturing the
valve stem A valve stem is a self-contained valve which opens to admit gas to a chamber (such as air to inflate a tire), and is then automatically closed and kept sealed by the pressure in the chamber, or a spring, or both, to prevent the gas from escaping ...
, which then allowed the inlet valve to drop open, resulting in the ignition by the
spark plug A spark plug (sometimes, in British English, a sparking plug, and, colloquially, a plug) is a device for delivering electric current from an ignition system to the combustion chamber of a spark-ignition engine to ignite the compressed fuel/air ...
of the pressurised fuel/air mixture within the
inlet manifold In automotive engineering, an inlet manifold or intake manifold (in American English) is the part of an engine that supplies the fuel/air mixture to the cylinders. The word '' manifold'' comes from the Old English word ''manigfeald'' (from th ...
and, eventually, the pumping of the ignited fuel outboard of the
rocker cover Rocker covers are covers that are bolted on over rocker arms in an internal combustion engine. They are called valve covers in the United States, Canada, and in situations where Rocker Arms are not present, such as some Overhead Cam, and most Du ...
and along the outside of the engine, leading to an extensive fire in the engine
nacelle A nacelle ( ) is a "streamlined body, sized according to what it contains", such as an engine, fuel, or equipment on an aircraft. When attached by a pylon entirely outside the airframe, it is sometimes called a pod, in which case it is attached ...
. Due to the fire originating in the induction system, where the
supercharged In an internal combustion engine, a supercharger compresses the intake gas, forcing more air into the engine in order to produce more power for a given displacement. The current categorisation is that a supercharger is a form of forced induct ...
fuel/air mixture was at higher pressure than atmospheric, the heart of the fire was much hotter burning and intense than would be the case in a simple fuel fire. Constantly fuelled by the broken intake, the fire burned rapidly along the wing and fuselage, eventually causing the outboard section of the starboard wing to separate from the centre section at approximately 350 feet (100  meters) of altitude. With the loss of a substantial part of the starboard wing, all control over level flight was lost, and the plane rolled inverted and struck the ground at approximately 150 mph (240  meters). The board found that the crew and passengers had not jumped immediately from the aircraft owing to several factors, including a loss of altitude while attempting to find an emergency field, the rapidly spreading fire, which blocked or impeded egress from the plane, and the fact that a sufficient number of parachutes were either not on board or were not being worn. Almost immediately following the crash, Prime Minister
Winston Churchill Sir Winston Leonard Spencer Churchill (30 November 187424 January 1965) was a British statesman, soldier, and writer who served as Prime Minister of the United Kingdom twice, from 1940 to 1945 Winston Churchill in the Second World War, dur ...
issued a directive requiring any test flights with civilians or scientific personnel to carry a sufficient number of parachutes for all individuals involved. After the RAF investigative board completed its report on the Halifax crash, it was ordered to be kept secret by Prime Minister Churchill, and the cause of the crash was not revealed publicly, even to the relatives of the deceased. As a result, numerous unfounded rumours of German sabotage as the cause of the crash would circulate for many years afterwards.


Personal life

Alan Blumlein had two sons, Simon Blumlein and David Blumlein. Outside his work Blumlein was a lover of music and he attempted to learn to play the piano, but gave it up. He enjoyed horse riding and occasionally went cub hunting with his father-in-law. He was interested in many forms of engineering, including aviation, motor engineering and railway engineering. He obtained a pilot's licence and flew
Tiger Moth The de Havilland DH.82 Tiger Moth is a 1930s British biplane designed by Geoffrey de Havilland and built by the de Havilland Aircraft Company. It was operated by the Royal Air Force (RAF) and other operators as a primary trainer aircraft. ...
aircraft of the London Aerodrome Club at Stag Lane Aerodrome. On one occasion, he persuaded a bus driver to allow him to drive the vehicle from
Penzance Penzance ( ; kw, Pennsans) is a town, civil parish and port in the Penwith district of Cornwall, United Kingdom. It is the most westerly major town in Cornwall and is about west-southwest of Plymouth and west-southwest of London. Situated ...
to
Land's End Land's End ( kw, Penn an Wlas or ''Pedn an Wlas'') is a headland and tourist and holiday complex in western Cornwall, England, on the Penwith peninsula about west-south-west of Penzance at the western end of the A30 road. To the east of it is ...
. On another he spent several hours assisting the operator of a railway
signal box In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The ''IEEE Transactions on Signal Processing'' ...
in his duties at
Paddington Station Paddington, also known as London Paddington, is a Central London railway terminus and London Underground station complex, located on Praed Street in the Paddington area. The site has been the London terminus of services provided by the Great ...
.


Tributes

*''Alan Blumlein Way'' is a road on the
Tektronix Tektronix, Inc., historically widely known as Tek, is an American company best known for manufacturing test and measurement devices such as oscilloscopes, logic analyzers, and video and mobile test protocol equipment. Originally an independent ...
campus in
Beaverton, Oregon Beaverton is a city in Washington County, in the U.S. state of Oregon with a small portion bordering Portland in the Tualatin Valley. The city is among the main cities that make up the Portland metropolitan area. Its population was 97,494 at the ...
, in keeping with their policy of naming roads after those who made significant contributions to the knowledge and understanding in the field of electronics. *There continues to be a meeting room named the Blumlein Room in the
Institution of Engineering and Technology The Institution of Engineering and Technology (IET) is a multidisciplinary professional engineering institution. The IET was formed in 2006 from two separate institutions: the Institution of Electrical Engineers (IEE), dating back to 1871, and ...
(IET) headquarters at
Savoy Place Savoy Place is a large red brick building on the north bank of the River Thames in London. It is on a street called Savoy Place; Savoy Hill and Savoy Street run along the sides of the building up to the Strand. In front is the Victoria Embankment ...
, following a major refurbishment in 2015. * A
Blue Plaque A blue plaque is a permanent sign installed in a public place in the United Kingdom and elsewhere to commemorate a link between that location and a famous person, event, or former building on the site, serving as a historical marker. The term i ...
commemorating Blumlein was erected in 1977 by the
Greater London Council The Greater London Council (GLC) was the top-tier local government administrative body for Greater London from 1965 to 1986. It replaced the earlier London County Council (LCC) which had covered a much smaller area. The GLC was dissolved in 198 ...
at his former home in
Ealing Ealing () is a district in West London, England, west of Charing Cross in the London Borough of Ealing. Ealing is the administrative centre of the borough and is identified as a major metropolitan centre in the London Plan. Ealing was histor ...
. * On 1 April 2015 an IEEE Milestone Plaque was posthumously presented for the Invention of Stereo to Alan Dower Blumlein. A ceremony was held at
Abbey Road Studios Abbey Road Studios (formerly EMI Recording Studios) is a recording studio at 3 Abbey Road, St John's Wood, City of Westminster, London, England. It was established in November 1931 by the Gramophone Company, a predecessor of British music c ...
attended by many leading audio experts and recording engineers. The plaque is now located on the right hand side of the front door of Abbey Road Studios. * In 2017, The
Recording Academy The Recording Academy (formally the National Academy of Recording Arts and Sciences; abbreviated NARAS) is an American learned academy of musicians, producers, recording engineers, and other musical professionals. It is famous for its Grammy Aw ...
posthumously awarded Alan Dower Blumlein with the 2017 Technical Grammy for the invention of Stereo and contributions of outstanding technical significance to the recording field.


See also

*
Blumlein generator A pulse-forming network (PFN) is an electric circuit that accumulates electrical energy over a comparatively long time, and then releases the stored energy in the form of a relatively square pulse of comparatively brief duration for various puls ...
* Blumlein transmission line, used to create high-voltage pulses with short rise and fall times.


Notes


References

;Citations ;Bibliography * *


External links


The crashed Halifax aircraft ''V9977''

Blumlein page at AlanTuring.net

Biography of Blumlein on IEEE Global History Network

Binaural test records and manuscripts created by Alan Blumlein and his research team at EMI
(British Library)
Official Alan Dower Blumlein website
{{DEFAULTSORT:Blumlein, Alan Dower 1903 births 1942 deaths Alumni of Imperial College London British electronics engineers English audio engineers English electrical engineers English people of German-Jewish descent English people of Scottish descent People educated at Highgate School People from Hampstead Radar pioneers Television pioneers 20th-century British inventors Victims of aviation accidents or incidents in England Victims of aviation accidents or incidents in 1942 British civilians killed in World War II