Microphones 101

Sound is energy that we can hear, but travels only so far before it disappears into the world around us. Until the invention of electrical microphones, in the late 19th century, there was no satisfactory way of sending sounds across. Today, by converting sound energy into electricity and the ability of storing information, microphones make it possible to send sounds and/or music to distant places around the world.

A transducer is a device that converts energy from one form to another. Microphones are a type of transducer, they convert acoustical energy, or sound waves, into electrical energy, or audio signal. 

The most important part of a microphone is the diaphragm, and it is made of a thin piece of material, such as paper, plastic or aluminium, that vibrates when struck by sound waves. When the diaphragm moves, it causes the other components inside the microphone to move, these vibrations are then converted into an electrical current that ultimately becomes the audio signal we can hear. 

1. Sound waves, carried by vibrations in the air, carry the energy towards the microphone.

2. Inside the microphone, the diaphragm moves back and forth as the sound waves hit it.

3. The coil that is attached to the diaphragm, moves back and forth as well.

4. The magnet produces a magnetic filed. As the coil moves back and forth through the magnetic field, an electric current flows through it.

5. The electric current flows out from the microphone to an amplifier or other sound recording device. The sound waves are now converted into electricity.

At the other end of the audio chain are the loudspeakers. These are also a type of transducer, working in the exactly reverse way of the microphones, they convert the electrical energy back into acoustical energy.

Bibliography:

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Glynn, L., 2020. The Different Types of Microphones Explained [online]. Studio D. Available from: https://www.dawsons.co.uk/blog/the-different-types-of-microphones-explained [Accessed 27 October 2020].

Hahn, M., 2019. Microphone Types: How to Choose the Right Mic for Your Sound [online]. Landr. Available from: https://blog.landr.com/microphone-types/ [Accessed 27 October 2020].

Media College, no date. How Microphones Work [online]. Media College. Available from: https://www.mediacollege.com/audio/microphones/how-microphones-work.html [Accessed 27 October 2020].

Woodford, C., 2008. How do microphones work? | Types of microphone compared [online]. Explain That Stuff. Available from: https://www.explainthatstuff.com/microphones.html [Accessed 27 October 2020].