Microphone
German inventor Johann Philipp Reis designed an early sound transmitter that used a metallic strip attached to a vibrating membrane that would produce intermittent current. Better results were achieved with the "liquid transmitter" design in Scottish-American Alexander Graham Bell's telephone of 1876 – the diaphragm was attached to a conductive rod in an acid solution. These systems, however, gave a very poor sound quality.
The first microphone that enabled proper voice telephony was the (loose-contact) carbon microphone. This was independently developed by David Edward Hughes in England and Emile Berliner and Thomas Edison in the US. Although Edison was awarded the first patent (after a long legal dispute) in mid-1877, Hughes had demonstrated his working device in front of many witnesses some years earlier, and most historians credit him with its invention. The carbon microphone is the direct prototype of today's microphones and was critical in the development of telephony, broadcasting and the recording industries. Thomas Edison refined the carbon microphone into his carbon-button transmitter of 1886. This microphone was employed at the first ever radio broadcast, a performance at the New York Metropolitan Opera House in 1910.
In 1916, E.C. Wente of Western Electric developed the next breakthrough with the first condenser microphone. In 1923, the first practical moving coil microphone was built. The Marconi-Sykes magnetophone, developed by Captain H. J. Round, became the standard for BBC studios in London. This was improved in 1930 by Alan Blumlein and Herbert Holman who released the HB1A and was the best standard of the day.
Archie Frederick Collins
Collins was granted U.S. patent 814,942 on March 13, 1906 for an arc-transmitter improvement which separated the telephone microphone circuit from the arc circuit, to avoid the problem of the arc current burning out the microphone. Although this was merely an incremental improvement on existing arc-transmitter technology, the company's stock promotion advertisements claimed this patent was "a broad one, covering the fundamental principles for transmitting and receiving articulate speech without connecting wires" that was supposedly "considered by the highest authorities on patent law to be one of the strongest to be issued since the one granted to Bell in 1876". (Early purchasers of Bell telephone stock had reaped fortunes, so it was a common tactic for early radio company stock promotions, aimed at impressionable "get-rich-quick" buyers, to suggest that similar increases would occur).