What is a carbon microphone?
The carbon microphone is seen as a simple device to turn sound into electronic signal. Some examples of their use where in telephones, radio broadcast systems and the popularity was at a peak around the 80's. The Carbon Microphone was eventually replaced by more powerful and less noisy microphone. Some carbon microphones are still used today due to their durability and working in low power environments.
Why do people tap carbon microphones?
The tapping of microphones came from carbon microphones as the carbon atoms would get stuck together sometimes and so needed to be hit to separate them to ensure the carbon microphone worked properly, this is still carried on today even though there is no advantage compared to just talking into it. Condenser microphones can get damaged with this practice.
How a carbon microphone works
Grey Circles = Carbon
Granules - Diaphragm (flexible electrode) moves, changing signal output strength
You will rarely come across this type of microphone and its not really got a place in location sound recording, but a nice piece of microphone history. Comment on what you have learnt on the carbon microphone below the related posts.