Category Archives: 1930s Microphone

1962 BBC Training Manual

In the 1951 BBC Microphones training manual we saw that the corporation functioned with a small selection of British manufactured microphones, most of which had been in service since the 1930’s.  So when I saw this Manual from 1962 I was curious to see how ‘Auntie’ had moved on into the swinging sixties.

BBC Training Manual 1962

Old favourites continued in use.                                                                                         BBC Training Manual 1962 STC Dynamic Microphones

The STC4021 ‘Apple and Biscuit’ first appeared in 1935 as did the famous Marconi A series ribbon microphone pictured on the page below. (The AXBT is the 4th generation).  The STC4035 was a lighter, updated replacement for the old STC 4017, which had been phased out in the mid 50’s. The 4032 is identical to the 4035 but housed in a neat handheld Bakelite body making it suitable for outdoor use in all weathers. The 4037 was designed for TV and has a rather more modern look (slim lightweight body and matt black finish). However, the capsule is still pretty much the same as the good old ‘Apple and Biscuit’. STC’s dynamic models were the tried and tested backbone of general purpose and outside broadcasting. The noise-cancelling STC4104 lip ribbon mic was used for sports commentary and noisy events. This was an updated version of the older Marconi lip ribbon microphone. More recently manufactured by Coles, the 4104 continues in production to this day.

BBC Training Manual 1962 Ribbon Microphones

So what was new?

FM broadcasting by the BBC began in 1955 and the audio frequency response was thereby extended from 5 kHz up to 15 kHz. The new FM system was also considerably less susceptible to noise and interference than AM. Although the old favourite microphones from STC and Marconi were still fine for everyday transmission of speech, when it came to the broadcasting of high quality music, mics with improved high end response were now required. With this in mind the BBC Research Department designed 2 new ribbon microphones (pictured above). First came the PGS (Pressure Gradient with a Single magnet) and from this developed the 4038. Manufactured by STC these new microphones were considerably smaller and lighter than the old Marconi AXBT, and had an almost flat frequency response up to 15 kHz. This was around ½ an octave higher than the mighty AXBT. Now manufactured by Coles the 4038 continues in service to this day and is still recognised as one of the finest ribbon microphones available.

The photograph below is rather bizarre. In real life the STC4033 is around 3x bigger than the Reslo! The Reslo was small and convenient for use on TV (as mentioned in my previous blog post). The STC4033 is an unusual hybrid, similar in design to the classic Western Electric 639 ‘Birdcage’. It has an ‘Apple and Biscuit’ type omni dynamic element, and a ribbon element. This gives a choice of switchable polar patterns. Using the elements separately we have Omni or Figure of Eight and by combining the outputs of both we obtain Cardioid. Nevertheless, by 1962 the STC4033 was a somewhat antiquated design and no match for the more sophisticated competition coming out of Germany and Austria.

BBC Training Manual 1962 Reslo and STC4033

Enter AKG and Neumann……….

A number of high quality condenser microphones now appeared in the BBC microphone locker. The legendary AKG C12 quickly became a firm favourite for the broadcasting of concerts and was very often the only microphone used to capture a symphony orchestra in glorious Mono! The AKG C28, C29 and C30 were perfect for solo performers on live TV. The variable extension pieces made it easy for unobtrusive positioning.

BBC Traing Manual 1962 AKG C12.jpgBBC Traing Manual 1962 AKGC28 .jpg

The Neumann KM54 cardioid, and the multi-pattern KM56 were also popular choices for high quality broadcasting.

BBC Training Manual 1962 Neumann KM54BBC Training Manual 1962 Neumann KM56

Other Microphones.

A number of other microphones are given a mention but not honoured with a photo. The Corporation was still very much dominated by BBC Radio and most of these microphones are from the rapidly evolving new world of BBC Television. TV presenters very often needed to keep their hands free and microphones ‘in shot’ needed to be small and unobtrusive.

BBC Training Manual 1962BBC Training Manual 1962BBC Training Manual 1962

The Placing of Microphones
The diagrams and explanations on the pages below provide an interesting insight into the lost world of recording and broadcasting in Mono.

BBC Training Manual 1962 Microphone Placement 01

The BBC philosophy for the broadcasting of classical music is best summed up in the opening sentence of the page below.  In the manual there is a clear distinction between music which requires the engineer to simply reproduce a ‘true balance’ created by the conductor and the performers (captured by one microphone), and more popular forms of music which require the engineer to create the balance from a number of microphones. Today this distinction has been all but lost.

BBC Training Manual 1962 Microphone Placement 02BBC Training Manual 1962 Microphone Placement 03

 Modern Dance Bands

BBC Training Manual 1962 Microphone Placement 05

Setups for Dance Bands.

BBC Training Manual 1962 Microphone Placement 06

The section above on Modern Dance Bands contains no mention of the latest Beat Groups, Rock’n’Roll or Skiffle. BBC thinking was clearly lagging at least 5 years behind the latest trends in popular music. If you were a teenager in 1962 the ensembles mentioned above are the sort of music your Mum and Dad would have liked! Within a couple of years British teenagers were under the bedclothes every night with a transistor radio listening to their favourite music coming from pirate radio stations such a Radio Caroline and Radio London, illegally broadcasting from offshore. It wasn’t until 1967 that the BBC threw in the towel and set up Radio 1 to cater for a younger audience!

STEREOPHONY

The final chapter of the manual is devoted to describing the basic principles of ‘STEREOPHONY’. Even though stereophonic records had been around for several years, by 1962 stereo broadcasting was still in it’s infancy. Around this time there were a number of experimental BBC broadcasts. In our house I can remember my Dad following the instructions for a particular broadcast by setting up 2 radio sets tuned to different programmes, one carrying the left-hand channel and one carrying the right !! Unfortunately the 2 radios were very different sizes and so the effect was somewhat less than perfect! It was not until 1973 that Radios 1,2 and 4 finally broadcast in stereo.

In Conclusion.

Although a small amount of space is given to sound in the context of television, this manual is firmly focused on ‘High-Quality Sound Production and Reproduction’ for BBC Radio. Tape had pretty much replaced 78 rpm discs as the primary means of recording and storing programmes. FM broadcasting was a huge technical leap forward and the arrival of some new condenser microphones further improved the quality of the output. Nevertheless, in many respects, even by 1962 ‘Auntie’ still had one foot firmly in the 1930’s !

 

 

 

 

Remembering D-Day June 6th 1944

CLICKHEREJohn Snagge announces the D-Day Landings in France 75 years ago today.

The STC4017c was used by the BBC throughout World War 2 to broadcast many momentous events and speeches. Possibly the most important communication tool of the 20th century it was the first microphone robust enough to withstand the rigors of serious outside broadcasting in a war zone.

For more information https://martinmitchellsmicrophones.wordpress.com/2013/06/21/stc-4017c-dead-or-alive/

World War 2 M.T.L.L.No2 Throat Microphone

M.T.L.L. No2 Throat Microphone

Found in a garden shed where it had been for at least the last thirty years, this WW2 British military throat mic looks a bit sad and dilapidated. The paint is falling off and the steel fittings are rusting, the elastic is past its best, and a hungry woodworm has been drilling into the crumbling leather. So imagine my surprise when I plugged it in and it immediately burst into life!

The M.T.L.L. No 2 was used by the RAF and by the army. The mic was worn around the neck and was designed to pick up vibrations direct from the voice box. The two leather covered sensors were pressed against either side of the throat. The great advantage of the throat mic was that it could be used effectively in very noisy environments, such as inside a tank or an aircraft in combat. Even loud sounds around the wearer would be largely rejected. Although the audio quality is not fabulous, speech has a high degree of intelligibility.

This view below is of the back of one of the sensors with the plastic cover removed. Inside there is a magnet, the polarity of which is marked on the metal case ‘N’ and ‘S’.  The wires are identified with red and blue cotton thread. (Hot and cold?)M.T.L.L. No2 Throat mic view inside the back

Below, (pinched from an ebay listing) is a photo of the front side of the mic, without its leather covering. Here there appear to be a couple of coils.M.T.L.L. No2 View inside front of throat mic

Below, the strip of steel which picks up vibrations from the throat is sitting on top of the coils and magnet. This assembly is held in place by the leather covering. The result of this ingenious arrangement is a small electrical (audio) output signal appearing at the red and blue wires.Inside throat mic M.T.L.L. No2

 

CLICK here to hear a short voice test of this unusual creation.

Conclusion.

It would be hard to exaggerate the importance of military communications during World War 2 and the crucial role played by the M.T.L.L. No 2 throat microphone.

 

The STC4001B Acoustic Baffle for the STC4021 (Apple & Biscuit) circa 1935.

The very first post that I wrote for this blog back in 2012 was about the STC4021 (Apple & Biscuit). Still one of my favourite microphones.  I even made a YouTube video to go with it! In the course of the video I mentioned the STC4001B Acoustic Baffle. According to the STC brochure this could be purchased to modify the frequency response and directionality of the microphone. These days the 4001B Acoustic Baffle is very hard to find. So imagine my surprise when a brand new old stock 4001B (still in the box) appeared on eBay. 

So I thought I had better ‘Buy it now‘ and make another video to celebrate the occasion!