Of the three main types of microphones available, let's start with the microphone most people are familiar with, the dynamic microphone. Dynamic microphones are the microphones you've most likely come into contact with if you've ever played on a stage, sung, or spoken into a microphone. Dynamic microphones are the “ice-cream cone” — shaped microphones that we all know and love. What makes this microphone “dynamic” is the way in which it picks up the sound and translates it into electricity. It has a small diaphragm made of plastic, usually Mylar (a type of plastic), that is placed in front of a coil of wire, called the voice coil. The voice coil is suspended between two magnets. If you remember from high school physics, when you move wire between magnetic fields, you can induce current. As sound hits the diaphragm, the voice coil moves and induces current. The current is fed down the microphone cable into your mixer or recording device. Voilà, sound!

Dynamic microphones are great for vocals, miking amplifiers, and close-miking drums. Dynamic microphones are durable, well constructed, usually last a long time, and — the best part — cheap. You can get a great microphone for under $100.

Dynamic microphones hear sound in cardioid patterns, which means they hear sound only directly in front of them. This makes them great for close-up miking situations, such as vocals, amplifiers, and drums, where you want nothing but the sound coming from the source with little or no ambience. One of the most important points about the dynamic microphone is its ability to handle extremely high sound-pressure level (SPL). As a result, you can use them in loud situations. However, dynamic microphones don't have full frequency response, which is helpful in many situations, and all are a bit different in the frequency levels they respond to. For example, the AKG D112 microphone is made for miking bass drums and bass guitars. Its frequency response emphasizes the bass frequencies and falls off at the high range, where there is little signal from a bass drum.

FIGURE 9-3

Microphone types