Photo By: By Roadside Guitars, on Flickr

History of the Microphone

By: Dan D.

The microphone, it is a tool frequently used in today’s world; it comes from over a century of rich history. We use it in telephones, public address systems, film production, music recording, television and the list goes on. It usually uses electromagnetic transducers or sensors to convert sound and air pressure into electrical signals. There are varying beliefs about the origins of the microphone, which very well depends on what definition you use.

The earliest rendition of the modern microphone, which we know today, is the carbon microphone, invented by David Edward Hughes in 1878. At first called a transmitter; this microphone had sufficient sound quality for its time and helped advance voice telephony. Hughes’ microphone incorporated loosely packed carbon granules which responded to varying pressure from a sound diaphragm. The electrical resistance would adjust accordingly and reproduce sound signals. He demonstrated his invention by mounting the transmitter on a sound box consisting of insects and amplifying the scratch noise they made. Over time improvements have been made to the carbon microphone by various inventors including Thomas Edison. In 1910, the first ever radio broadcast used a carbon microphone for a performance at the New York Metropolitan Opera House.

Edward C. Wente of Bell Laboratories developed the condenser microphone in 1917. This microphone has the diaphragm acting as one of the plates of a capacitor. The vibrations created by sound would change the distance between the plates. The condenser microphone was employed for recording and broadcasting, notably at the BBC (British Broadcasting Corporation) in the 1920s. Usage was limited since the microphone was susceptible to moisture causing a “frying” sound. The condenser microphone fell out of favor in the mid-thirties for more improved microphones. Moreover, the first carbon and condenser microphones were omnidirectional, meaning they received vibration signals from all directions.

In 1930, Alan Blumlein, an English electronics engineer at Western Electric, invented the moving coil microphone. This microphone had a diaphragm made from sheets of aluminum foil and balsa wood. An aluminum motive coil would be pinned to the diaphragm. Therefore, when the diaphragm vibrates, the coil moves in the magnetic field producing sound. Western Electric’s 618A electrodynamic transmitter model became the first dynamic microphone. Dynamic microphones are sturdy, cost efficient and resistant to moisture. This made them famous for on-stage use in entertainment.

Later that same year the first ribbon microphone appeared, created by Harry F. Olson from RCA. The idea came from a modified ribbon loudspeaker. This variation uses a nanofilm of electrically conductive ribbon located between the poles of a magnet to generate sound by magnetic induction. Ribbon microphones are usually bidirectional, which means they detect sounds from only two sides of the microphone. RCA’s 44-A ribbon microphone, with its seamless sound and fine aesthetics, became the dominating microphone for broadcasting up until the 1940s. Due to being easy on the eyes the 44-A microphone has one of the most identifiable shapes in the world.

Olson understood that there was a demand for more directional microphones, along with the quick advancement of television and film technology. In the 1930s, with the ingenuity of Olson, RCA had considerable success with their “77” microphone product line, especially the Type 77-DX in 1932. This single ribbon model was the first to introduce pattern control, to give the microphone versatile microphone directionality. The classic Type 77-DX can be adjusted to achieve a variety of directional patterns, including bidirectional, unidirectional and more. Furthermore, the recognizable shape of the 77-DX has been used by graphic artists to symbolize speech. The microphone has been utilized for vocal recordings by Frank Sinatra, Johnny Cash, Bing Crosby and many others.

Shure Inc., an American audio products corporation, became highly acclaimed in 1939 with the release of the Unidyne Model 55, designed by Ben Bauer. Bauer was able to create controlled cancellation and produce a cardioid directionality by using a system called “uni-phase”. Uni-phase exploits the time delay networks of sounds arriving at the back openings of the microphone. Shure’s Unidyne 55 was part of some of the most iconic moments in history, spanning seven decades. Presidents used it in public addresses, including John F. Kennedy and Harry S. Truman. Fidel Castro had the microphone in front of him on the cover of Life magazine on January 19, 1959. Martin Luther King, Jr. delivered his famous, “I Have a Dream” speech with the prominent microphone in 1963. The Unidyne series was also the microphone of choice for many renowned artists and performers including Ella Fitzgerald and Elvis Presley.

Shure Inc., had another breakthrough with their SM series microphones, particularly the SM57 and SM58 model in 1965 and 1966 respectfully. Since then they have been the two best-selling microphones in the world. The “SM” stands for studio microphone. They are both cardioid dynamic microphones that share identical features, the only difference being their grilles. Musicians commonly use both microphones for live vocal applications and studio recording. Every U.S. president has used the Shure SM57 since Lyndon Baines Johnson. The SM58, their sibling, has been the industry standard in handheld vocal performance microphones and been inducted into the TECnology Hall of Fame.

Currently, the latest research has led to the development of fiber optic microphones. Instead of sensing changes in magnetic fields similar to previous microphones, fiber optic microphones converts sound into electrical signals by detecting fluctuations in light intensity. Fiber optic microphones have EMI/RFI immunity, meaning they do not react to or influence any electrical, magnetic, electrostatic or radioactive fields. These microphones also are resistant to heat and moisture. Furthermore, they can be manufactured with custom impedance and directionality. These features made fiber optic microphones ideal for industrial or medical situations, where conventional microphones are useless or pose a danger.

There is no dispute that the microphone is a mainstay in today’s society. Its vibrant history showed the extraordinary impact it has on the world. It assisted with the invention of the telephone; it played a monumental role in the radio and television industry, and leaders and revolutionaries have used it to inspired generations of people. The complete list of the contributions of our favorite gadget would be able to fill bookshelves. So what does the future hold? We at MobiMic are changing the conference environment by making the microphone more interactive, convenient and sharable. Follow our story and watch us make history.