Invents the microphone
The microphone is one of Edison's inventions. Its purpose is to increase sound while sending it over the wire. The passing of a delicate camel's-hair brush is magnified so as to seem like the roar of a mighty wind in a forest of giant pines.
The megaphone
Next came the megaphone, an instrument to bring far-away sounds to one's hearing. By means of this instrument, persons talking a long distance apart are able to hear each other with ease.
The phonograph, which can reproduce the human voice and other sounds almost perfectly, was invented by Edison in 1876.
EDISON'S GREAT WORKSHOP AT ORANGE, NEW JERSEY
Edison's first phonograph
Sounds reach the ear by means of air waves which the sounding body sets in motion. In Edison's first phonograph these waves struck a bit of taut parchment, and were marked by a needle on a tinfoil disc. But tinfoil does not hold its shape well. In 1888 Edison patented a better phonograph in which the record was made on a wax disc.