A brief history of microphones

In the beginning The German physicist Johann Philipp Reis (1834–1874) is a strong candidate for the title. His design for a 'sound transmitter' (optimised around 1861), used a metallic strip resting on a membrane with a metal point contact completing an electrical circuit. It was Reis's theory that, as the membrane vibrated, the metal point bounced up and down ‘producing intermittent contact and thus a varying current synchronous with the vibrations’. He believed the height of the bounce and the force of its return caused variations in the amplitude of the current pulse proportional to the intensity of the sound. It worked in a fashion, but not really well enough for intelligible speech!