The BBC-Marconi Type A is a

ribbon microphone A ribbon microphone, also known as a ribbon velocity microphone, is a type of microphone that uses a thin aluminum, duraluminum or nanofilm of electrically conductive ribbon placed between the poles of a magnet to produce a voltage by electrom ...

that was produced by the

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. ...

and Marconi between 1934 and 1959. The microphone has been described as "iconic" and a symbol of the BBC.

History

In the early 1930s, the BBC became aware of

RCA The RCA Corporation was a major American electronics company, which was founded as the Radio Corporation of America in 1919. It was initially a patent pool, patent trust owned by General Electric (GE), Westinghouse Electric Corporation, Westin ...

's model 44 ribbon microphone that was used in

Hollywood Hollywood usually refers to: * Hollywood, Los Angeles, a neighborhood in California * Hollywood, a metonym for the cinema of the United States Hollywood may also refer to: Places United States * Hollywood District (disambiguation) * Hollywoo ...

. Each pair of microphone and

amplifier An amplifier, electronic amplifier or (informally) amp is an electronic device that can increase the magnitude of a signal (a time-varying voltage or current). It may increase the power significantly, or its main effect may be to boost th ...

would have cost the BBC £130 (approximately £6,500 in 2009Based on a

retail price index In the United Kingdom, the Retail Prices Index or Retail Price Index (RPI) is a measure of inflation published monthly by the Office for National Statistics. It measures the change in the cost of a representative sample of retail goods and ser ...

calculatio

/ref>). As this was not within the BBC's budget, they designed their own microphone, the Type A, alongside Marconi. There were initial concerns that the new design Patent infringement, infringed the patent of the RCA microphone, but these were overcome. The Type A was produced at a cost of £9 each (approximately £475 in 2009). The original Type A microphone was designed by engineer F. W. Alexander under the guidance of H. L. Kirke's Research Department at the BBC. In 1940, the Type A was used in the broadcast of Charles de Gaulle's 1940 appeals. In the early 1950s, the BBC began to design the Type A's successor. The first model was the

pressure gradient In atmospheric science, the pressure gradient (typically of air but more generally of any fluid) is a physical quantity that describes in which direction and at what rate the pressure increases the most rapidly around a particular location. The ...

PGD design. In 1953, production began on the PGS (pressure gradient single) ribbon microphone in agreement with the company

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). In the mid-1970s, STC's manufacturing was transferred to Coles Electroacoustics, who continue to manufacture the PGS under the model number 4038.

Technical

Four versions of the microphone were produced – the "A", "AX", "AXB", and "AXBT". The original microphone used a thick aluminium ribbon which produced a harsh

resonance Resonance describes the phenomenon of increased amplitude that occurs when the frequency of an applied periodic force (or a Fourier component of it) is equal or close to a natural frequency of the system on which it acts. When an oscillat ...

. This was soon replaced with a thinner ribbon, and was named Type AX. In 1943, the AXB model was launched, which featured balanced wiring. In 1944, the microphone was renamed the AXBT with the addition of a Ticonal magnet to increase sensitivity by 6 decibels. The AXBT weighed approximately . The microphone had a

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polar pattern. The aluminium ribbon was less than one

micrometre The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer ( American spelling), also commonly known as a micron, is a unit of length in the International System of ...

thick.

Footnotes

Sources

* (

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cached version of page) * * * * * * * * * * {{refend Microphones Products introduced in 1934 BBC history