Microphones are designed to take acoustical energy (sound) and convert it into electrical energy.
There are mainly three microphones types that are used:
In this lesson we are only going to discuss dynamic and condenser microphones because they are most commonly used.
There are a four fundamental characteristics of a microphone which will be covered here.
How it converts sound to electricity
How it response to different frequencies
The direction the microphone response
What type of electricity is created
We will look at each of these and hopefully it will make sense!
Dynamic microphones have a relatively simple construction and do not require an outside power source. These microphones have a thin piece of material, called a diaphragm.
When sound waves hit the diaphragm, it moves a coil of wire, which is attached to the diaphragm, moves with it. As the coil moves back and forth, it passes through a magnetic field created by a magnet in the center.
When a conductive material moves in a magnetic field, it creates electricity. So this creates an electrical signal which relates to the sound.
Dynamic microphones are great because they can handle loud sounds without distorting. However, with that they are not great is picking up quiet, distant, or high frequency sounds. They are great for vocals and horns, but not always stringed instruments with a higher frequency range. Also, because the magnet and the coil create their own voltage, it does not need an external power source.