Cone Speaker
The cone speaker that's used in the majority of today's speaker systems was invented back in the 1800s. Like the first microphone, which is essentially a speaker in reverse, development with improvements came in stages. As early as 1861 Johann Philipp Reis, who was working on a telephone prototype, had a speaker that could reproduce tones clearly, and after some tweaking could also reproduce a very muffled-sounding voice.
In the 1870s Thomas Edison, Nikola Tesla, Ernst Siemens, and Alexander Graham Bell were all trying to develop a working loudspeaker that could reproduce a human voice. Bell's speaker used a permanent magnet and an iron diaphragm and was part of the telephone that he was granted a patent for in 1876.
Edison was issued a British patent for a compressed air speaker system for his cylinder phonograph, but instead opted for a diaphragm that was amplified by the metal horn, the exact reverse of the recording process. Emile Berliner and Eldridge Johnson of the Victor Talking Machine Company had also developed a compressed-air loudspeaker for one of their record players, known as the Auxetophone. However, it had neither good sound quality nor any way to control the volume.
Then, in 1898 Sir Oliver Lodge, a British physicist and writer, who was working on wireless telegraphy, invented the dynamic moving-coil speaker, which was the forerunner of all modern cone speakers.