Way before it could be used as a throwing object, the microphone has a long history in the world.
The microphone is a device that converts sound waves into electrical signals, which can then be amplified, recorded, or transmitted. The microphone has been an essential tool for communication, entertainment, and science since its invention in the 19th century. But how did the microphone come to be? What were the challenges and innovations that shaped its development? This article will explore the early history of the microphone, from its origins in acoustic experiments to its modern applications in various fields.
The Origins of the Microphone
The word "microphone" was first coined by Sir Charles Wheatstone, an English physicist and inventor, in 1827. Wheatstone was interested in acoustics and sound transmission, and he devised a device that could amplify weak sounds. He called it a microphone, meaning "small sound" in Greek¹. However, Wheatstone's microphone was not an electrical device, but rather a mechanical one that used resonating chambers and tubes.
The first electrical microphone was invented by Emile Berliner, a German-born American inventor, in 1876. Berliner was inspired by the telephone, which had been invented by Alexander Graham Bell earlier that year. Berliner wanted to improve the sound quality of the telephone by creating a better voice transmitter. He came up with a device that used a metal diaphragm attached to a contact point, which vibrated when sound waves hit it. The vibrations changed the electrical resistance of the contact point, creating a varying electric current that corresponded to the sound waves².
Berliner's microphone was patented and sold to the Bell Telephone Company for $50,000. However, his patent was later challenged and overturned by Thomas Edison, who claimed that he had invented a similar device before Berliner. Edison's microphone used carbon granules instead of a metal diaphragm, which increased the sensitivity and loudness of the device².
The Carbon Microphone and Beyond
The carbon microphone became the standard for telephones and other sound applications for many years. It was also used by David Edward Hughes, a British-American inventor and music professor, to demonstrate the wireless transmission of sound in 1878. Hughes used a carbon microphone connected to a spark-gap transmitter to send radio signals over a short distance. He also used a carbon microphone as a detector to receive the signals. Hughes's experiments were among the first demonstrations of radio communication³.
However, the carbon microphone had some limitations, such as low fidelity, high noise, and limited frequency response. In 1916, Edward C. Wente, an engineer at Bell Laboratories, invented the condenser microphone, which used an electrically charged metal plate as a diaphragm and another plate as a fixed electrode. The distance between the plates changed when sound waves hit the diaphragm, creating a varying electric charge that could be amplified.
The condenser microphone offered higher fidelity and wider frequency response than the carbon microphone, but it required an external power source and was more expensive and fragile. It was mainly used for laboratory and studio purposes until the invention of the electret condenser microphone in 1962 by James West and Gerhard Sessler at Bell Laboratories. The electret condenser microphone used a permanently charged material as one of the plates, eliminating the need for an external power source. It also reduced the size and cost of the device, making it suitable for mass production and consumer applications.
Other types of microphones that were developed in the 20th century include:
- The dynamic microphone, which uses a coil of wire attached to a diaphragm that moves within a magnetic field. The movement of the coil induces an electric current that corresponds to the sound waves. The dynamic microphone is robust and versatile, and can handle high sound pressure levels.
- The ribbon microphone, which uses a thin metal ribbon suspended between two magnets as a diaphragm. The ribbon vibrates when sound waves hit it, creating an electric current that corresponds to the sound waves. The ribbon microphone is sensitive and delicate, and produces a warm and natural sound.
- The crystal microphone, which uses a piezoelectric material that generates an electric voltage when subjected to mechanical stress. The piezoelectric material is attached to a diaphragm that vibrates when sound waves hit it, creating an electric voltage that corresponds to the sound waves. The crystal microphone is cheap and simple, but has low fidelity and limited frequency response.
The Modern Applications of Microphones
Today, microphones are used for various purposes in different fields, such as:
- Communication: Microphones are essential for telephones, radios, intercoms, public address systems, voice over internet protocol (VoIP), speech recognition, video conferencing, podcasting, etc.
- Entertainment: Microphones are indispensable for music recording and performance, broadcasting (radio and television), film production (sound effects and dialogue), gaming (sound design and voice chat), karaoke (singing along to recorded music), etc.
- Science: Microphones are useful for acoustic research and measurement, such as sound level meters, spectrum analyzers, acoustic cameras, sonar (sound navigation and ranging), ultrasound (high-frequency sound waves for medical imaging and therapy), etc.
The microphone is a remarkable device that has revolutionized the fields of communication, entertainment, and science. It has enabled us to capture, amplify, transmit, and reproduce sound in various ways. It has also allowed us to express ourselves, share our ideas, and enjoy our culture. The microphone is a testament to the power of human ingenuity and creativity..
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