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?)
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.
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.
CLICK here to hear a short voice test of this unusual creation.
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.
Posted in 1930s Microphone, 1940s Microphone, Mititary Microphones, Noise- cancelling microphones, Uncategorized, Vintage Microphones, WW2 Microphones
Tagged 1930s Microphone, 1940s Microphone, Military Microphone, Throat Microphone, Vintage Microphone, WW2 microphone
In the post yesterday came a small cardboard box containing a very pleasant surprise. On reading my last post on the STC4032, one of my readers had observed, that I didn’t have the 4001.A. wind shield. These days they are extremely hard to find. He happened to have 2 and so he sent me this as a present! That is very kind and made my day. So, a big thank you to John Machling
And it is in absolutely perfect condition!
The construction of the wind shield is interesting, consisting of a cleverly designed dome of fine wire mesh packed with rubberised hair and other fibres. (Even the thickness and spacing of the wire and hair/fibre is critical! ) An airtight rubber seal easily attaches the wind shield to the mic.
No. It is not a nest for an extremely small bird!
To understand exactly how this slightly crazy-looking piece of vintage British technology works it is worth reading the original patent application which explains all.
Patent Application for STC4001.A.
With the wind shield in place, the level of noise caused by winds in the range of 10 – 30 mph is reduced by up to 16 db, with surprisingly little effect on the frequency response. It also provides a valuable additional layer of waterproofing. It certainly looks like it should be very effective, and as soon as we have some really bad winter weather I will get outside and record a demonstration!
Posted in 1950's Microphone, 1960's Microphone, BBC Microphones, Microphone Tech Specs, Microphone techniques Ancient & Modern, STC Microphones, Vintage Microphones
Tagged BBC Microphones, BBC outside broadcasting microphone, Microphones for Television, STC Microphone, STC4001.A. Wind Shield, Vintage Microphone