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The Marconi-Sykes magnetophone

In May 1923, an improved microphone of a more sensitive type was introduced which was to take radio from sounding like an ordinary telephone to a medium with a stunning new auditory clarity. These were a vast improvement on the original telephone handset type (Baker, 1984, p 193). Although the Marconi-Sykes microphone would be succeeded by a more practical design within a few years, its enhancement of radio’s sound quality and the new types of programmes it made possible would have cultural effects that would resonate for decades.

Figure 2

Colour photograph of a magnetophone from 1923

A Marconi Type M.I.G.1. magnetophone, 1923–24; gifted to the National Media Museum in 2012 by the BBC

It was known as the Marconi-Sykes magnetophone, and was the first purpose-built microphone to be commissioned by the BBC. Its extremely sensitive moving coil design was based on an earlier magnetophone design patented by A S Sykes, which had been substantially improved by Round. The new microphone and an artificial echo system were two of Round's many contributions to the early stages of the art of broadcasting (Baker and Hance, 2010).

The body of the microphone is a large magnetised cylindrical iron pot, giving it a weight of 20 pounds. The sound-sensitive coil is pancake shaped and made of very fragile fine-gauge aluminium wire. It is supported at one side on a backing of paper, which in turn is supported on three or four cotton wool pads covered by a thin layer of Vaseline. The cotton wool is used because the coil moves so easily that its movement has to be dampened. The coil is suspended between the central pole-piece and pot-shaped outer container of the powerful electro-magnet, this magnet requiring a current of 4 amperes to be generated from an 8-volt accumulator (battery). Sound waves shaking the pancake coil create electric currents within that coil, which are perfect electrical reproductions of the original sounds (Burrows, 1924, p 90). These currents are subsequently amplified.  

Due to its sensitivity, the microphone was usually supported in a cradle or sling of spongy ‘sorbo’ rubber to help isolate it from mechanical vibrations – anything more than a slight movement could be enough to dislodge the coil completely.  

If the studio became too warm, this had the effect of reducing the adhesiveness of the Vaseline. ‘Some engineers preferred butter,’ wrote Eckersley; ‘the use of either Vaseline or butter was a matter of some rivalry, though both tended to melt in heated studios. Rubber solution became the ultimate answer to the problem’ (Eckersley, 1997, p 80). It also became a matter of routine to change the cotton wool just before a broadcast if the microphone had been in use for some time beforehand (Pawley, 1972, p 41).
In the studio, the microphone was usually placed within a copper mesh box called a Faraday Cage, invented in 1836 by English scientist Michael Faraday. This was necessary to block out electromagnetic interference to which the sensitive microphone was susceptible. Microphone, rubber cradle, and cage would sit on a sturdy wooden splayed stand, which could be wheeled around the studio. A knife switch on one leg of the stand was used to turn the microphone on or off. The whole unwieldy apparatus was nicknamed the ‘Meat Safe’ because of its resemblance to meat storage cupboards in use at the time.

Figure 3

Colour photograph of a 1923 meat stand with accompanying magnetophone

A 1923 BBC ‘Meat Safe’ stand with its accompanying magnetophone alongside

The microphone was first used in the studio at Savoy Hill in central London, which opened on 1 May 1923, about six months after the formation of the British Broadcasting Company. ‘The microphone, on its four-legged trestle with rubber-tyred wheels, stands about 6 feet away from the south wall,’ wrote Arthur Burrows, BBC Assistant Controller and Director of Programmes, in 1924. ‘The story of this microphone, which is gradually being introduced to all stations, is itself one of the romances of wireless’ (Burrows, 1924, p 89).

The challenges of microphone design represented just one of a number of technical problems for the early BBC which, as Scannell and Cardiff describe in significant detail, needed to be overcome before listening to radio could become a simple, trouble-free social activity (Scannell and Cardiff, 1991, pp 356–80). In the mid-1920s, most of the BBC’s listening audience was still equipped with crystal sets, which necessitated the use of headphones. Most crystal sets were designed with only one set of terminals meaning only one person at a time could listen to this type of receiver (Scannell and Cardiff, 1991, p 357). Valve sets used the mains or batteries, and could provide more volume. The loudspeaker invited shared listening and encouraged more radio listening, due to resulting freedom to listen in combination with other activities. ‘Although valve receivers played a more prominent role in the story of the emergent radio industry, crystal sets were to outnumber them until 1927, and to that extent may be said to have dominated the early years of broadcasting’ (Geddes and Bussey, 1991, p 16–17). They add that broadcast sound quality was important for crystal set listeners due to the lack of amplification, and the fact that ‘receiver and loudspeaker usually produced more distortion than crystal set and headphones did’.

Figure 4

Black and white photograph of an early audio listening device with attached headphones

A typical crystal set of the early 1920s with headphones and spare coil

The magnetophones were short-lived, taken out of use from 1925 to 1927 (West, 1972, pp 14–16) largely in favour of the compact and more efficient marble-bodied Marconi-Reisz carbon granule microphones. Although these were not nearly as sensitive as the magnetophones, the Reisz microphones were far more widely used by the BBC because they did not require the same high level of amplification. By 1929, all but one of the Savoy Hill studios was fitted with Reisz microphones. The one not so fitted had a Western Electric condenser (i.e. electrostatic) microphone, which had appeared in 1928. Because of its low output this microphone required a one valve head amplifier (Pawley, 1972, p 119).

In November 2012, the National Media Museum in Bradford, West Yorkshire, officially acquired an original BBC ‘Meat Safe’ stand and two original magnetophones as part of a collection of 994 pieces of historic radio and television equipment generously gifted by the BBC to help celebrate the BBC’s ninetieth anniversary. This collection included many microphones used by the BBC over its history. One of H J Round’s earlier electro-dynamic microphones of 1923 – the precursor of the magnetophone – was also donated by the BBC to the Museum in 2015. Used prior to the construction of the Savoy Hill studios, it is believed to be the only known example remaining of its type, and would have been used in conjunction with three other identical units tuned to differing segments of the audible frequency spectrum. The BBC has also donated an example of the successor to the magnetophone, the Marconi-Reisz marble microphone.

Before radio broadcasting with the magnetophone, mechanical music had required, as described by Lacey, ‘listener compliance in the completion of the “transparency effect” of the gramophone, learning to trust and accept mechanically reproduced sounds as real’ (Lacey, 2013, p 68). The magnetophone brought with it a higher level of transparency in the medium, making any broadcast which used it more lifelike. Independent of the content of the broadcast, this improvement was an emotive moment for the listener. Rothenbuhler and Peters describe this kind of ‘pay-off’ for the audiophile as a pseudo-religious moment of transcendence in which ‘the medium disappears [and] there is the possibility of a communion’ when we ‘break through to the other side’ (Lacey, 2013, pp 68–9; Rothenbuhler and Peters, 1997, p 253). Due to the sudden improvement in sound quality provided by the magnetophone, listeners immediately became less aware of their crystal or valve wireless sets, and more aware of the programme they were listening to. There was a new freedom for the radio listener to experience intimate feelings. Radio as a whole passed a milestone in its transition from a niche to a popular pastime, from technical curiosity to the background of everyday life.


Component DOI: http://dx.doi.org/10.15180/150402/003