Microphone Overview: Dynamic Type
Dynamic microphones have several qualities that make them unique. They can handle a lot of volume (technically known as SPL, meaning sound pressure level), which makes them perfect for extremely loud signals, such as drums, amplifiers, and some rock vocalists. Dynamic mics are also not as transparent (they don’t accurately represent high frequencies) as condenser mics, so they often impart a dirty or gritty sound to the signal.
The dynamic microphone uses a magnetic field to convert the sound impulse from the diaphragm into electrical energy, as shown in the following illustration. The diaphragm is often made of plastic or Mylar and is located in front of a coil of wire called a voice coil.
The voice coil is suspended between two magnets. When the diaphragm moves (the result of a sound), the voice coil moves as well. The interaction between the voice coil’s movement and the magnets creates the electrical signal.
The sound of a dynamic mic can be described as somewhat boxy, meaning that these mics don’t represent the highest or lowest frequencies of your hearing spectrum accurately (not necessarily a bad thing). Dynamic mics are also durable.
Rough treatment probably won’t damage them much, aside from the diaphragm, and a tough metal screen protects it. Dynamic mics are typically used for live shows. These mics are often very inexpensive to buy and maintain; you can get a good dynamic mic for about $100.