The Marconi M.M.E.5 Audiometer & TF444A & TF895 Acuity Meter

by Nigel Adams

In our first blog we covered the background history of Marconi Instruments and how the company came into being. This time we begin our journey through the various pieces of instrumentation aimed at the field of medical science. 

Some of the initial work into the medical electronics sector was undertaken before WW2, when the company was still known as Marconi – Ekco Instruments. It was known as the ‘Audiometer’ and produced for use in hospitals or larger doctors’ practices/institutions (probably prior to the establishment of the modern ‘clinic’ as we know it now). 

Initially this unit was marketed as the M.M.E 5 (Marconi Medical Equipment), it was a cream painted rectangular metal casing approximately the size of a large shoebox, with a top mounted carry handle and suited for AC and DC Mains operation. Remembering this was before the national grid was established and a number of locations away from towns had DC mains supplies – possibly generated locally or even on-site, using a stationary engine as a power plant to drive a generator. 

The unit contained a headset to be worn by the patient, a patient signalling switch and a handheld microphone used by the Otologist conducting the test.   A ’normal’ range of audible hearing is regarded as being from below 20Hz (Hertz, formerly cycles per second) up to around 20KHz (20,000 Hertz) for a typical person – of course it is known that most peoples’ hearing capability decreases as we age. So this unit would cover the range suitable for children as well as adults. 

In operation, the Audiologist (Otologist) would set up the equipment such that the patient placed the headset over one ear and the sound level adjusted so that the user could hear a tone. The frequency and levels were then adjusted over the range of the test and the patient could indicate when they were no longer able to hear the tone by pressing the signalling switch. The Otologist would then record the results and form a diagnosis. The process would then be repeated for the patient’s other ear. For patients with profoundly hard of hearing there was a bone conduction unit, and a Masking unit (for additional tuning) was offered as optional accessories. 

It was clear that this type of examination became much more important during and after WW2 due to the debilitating effects of loud explosions and gunfire etc. that the armed services and general public would experience during those years. Hearing loss/damage and acute deafness became a major issue in these post war years. 

The first recorded use of this equipment is shown in a company advertisement for a demonstration stand in 1937 at the Physical Society Exhibition (Stand 16).

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MME 5 Audiometer.jpg
improved audiometer TF444A advert .jpg

During the war years Marconi Instruments name succeeded the Ekco branding and the later model of Acuity Meter replaced the MME5 , becoming the TF444 and TF444A. An advertisement for this appeared in the December 1943 issue of ‘Nature’ magazine – costing the princely sum of £12-0-0d  (for placement of the advert!).

Interestingly, mention is made of ‘subject to approval of the appropriate authority’ in the text. Such items being restricted in their use to certain facilities (wartime restrictions still being in force). 

The later TF444 /TF444A and subsequent TF895 models were similar in operational principle to their earlier counterparts, although there were new features and a restyled casing. This equipment marked one of the first aids to modern diagnosis and treatment of debilitating hearing conditions that benefitted the wider public. 

For further reading about Marconi’s early life and his business developments, please see other reference material in the archive at George Marshall Medical Museum.

Work Experience with the team at GMMM...

Hi my name is Richie Durie and I am a student at Prince Henry's High School and I have been working here on a week’s long work experience. I have been working at Charles Hastings Education Centre and Worcestershire Royal Hospital in the library, Medico-Legal team, Learning and Development and the Museum. Firstly I would like to thank everybody I worked with for such a great and helpful experience with my time here. 

On my first day I spent the day in the library expecting to be as bored as anything, however thanks to David I enjoyed my time thoroughly and the work he set me was enjoyable. The next day I went to the Alexandra hospital to work with the medic-legal team, with which I was unsure of what they did and I was intrigued to find out and learn from them. Jane was fantastic, with not only explaining what she does and explaining the role of her team she tried her best to help me understand it and I would like to thank her and her team for that! After a successful first two days, on the Wednesday I went back to the library to work with Dianne and David again and yet did some different work and I was still entertained and eager! I would like to thank again Dianne and David for my time in the library. On the Thursday I worked with the Museum in the morning which was truly fascinating in itself and Louise asked if I could help her with the talk and tour she gave to the school which visited. I learned a lot about all the different treasures and old medical equipment and the working life around it. All the jobs are fascinating and are all spikes in my interest. And in the afternoon I spent my time with Jane on the front desk handling the stressful, busy ad useful jobs that are needed to keep this place running smoothly!

The amount of work and effort needed to do that is immense and I respect Jane for working so hard and still stay positive and enjoy herself! Friday morning I was back in the museum designing the worksheet shown in this picture- used for the children in the backpacks for the children to walk round. And after doing that I am currently writing this! I would like the thank Louise a lot for what she has taught me and the opportunity she has given me!

Overall I have had a fabulous time here and would like to thank everybody involved who have helped me, and allowed me to work here!

Richard Work Experience Student

Medical Electronics - introduction. Guest Blog Nigel Adams

Hello everyone,

My name is Nigel Adams and would like to welcome you to an occasional series of blogs covering historical medical electronics , specifically from the Marconi Company.

My background is that I joined Marconi Instruments as an apprenticed engineer in 1975 and remained with the company in various roles until its sale when the breakup of GEC (the Marconi holding company) occurred in 1998. 

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The business went through a number of ups and downs as do many similar industries and is now  American-owned and no longer directly in the same sphere of business. But the history of the company as Marconi Instruments is a fascinating and varied journey through electronics development and how it impacted the way we lived and its effect on the environment through the years following the Second World War.

By way of introduction and to ‘set the scene’ so to speak, this first blog will look at the history of the company and its involvement on all forms of electronics that have been developed up to the time when the company ceased to exist as an operating identity.

Guglielmo Marconi was an Italian engineer with a flair for physics and scientific development, his early experiments with radio transmission gained him recognition in many scientific fields. Unfortunately he was unable to obtain sufficient support from the Italian government of the time and then relocated to Great Britain where he went on to establish the ‘Marconi Wireless Telegraph Company’ (MWT) around 1920 and headquartered in Chelmsford, Essex.

As the MWT business expanded, it required specialist test and measurement equipment to assist in production of its radio systems, additionally Marconi established a marine division that went on to specialise in Radar and other navigational electronic aids. 

One of Marconi’s early claims to fame was the installation of his radio system onboard the RMS Titanic, which proved valuable in helping save some of the many lives from the stricken liner when it struck the iceberg in 1912.

Marconi himself continued research into shorter and shorter radio waves and ventured into further development of radar and X-ray technology until his death in 1937. As a mark of respect for his genius, all radio stations around the world closed down for a short period and the ether was as quiet as it had been before.

From this expansion was born Marconi Instruments in 1936, which previously, had collaborated with E.K. Cole of Southend on Sea who manufactured domestic radios amongst other items.

With the onset of WW2, the business was considered at risk of bombing, being so close to the east coast. 

In a single weekend the business relocated initially to High Wycombe and then settling permanently in St.Albans around 1940, where it became the largest single employer.

Marconi Instruments remained in St.Albans until 1990, at one point occupying three separate sites at the same time. It was here that one of the product ranges ventured into the realm of medical equipment, and so the story begins…

For further reading about Marconi’s early life and his business developments, please see reference material at the George Marshall Medical Museum.