- Dynamic Microphones
In dynamic microphones a physical cone acts like a lens to concentrate the incoming sound waves. The concentrated energy of these sound waves moves the cone and its attached coil of wire back and forth inside a magnetic field. The magnetic field induces electricity to flow through the wire to produce an electrical signal which is the microphone’s output.The electrical signal is analogous to the original sound wave: the voltage and current are proportional to the original sound.Dynamic microphones are well known for their versatility and their durability, but are not the best choice for reproducing high and low frequencies; dynamic microphones require significant energy to move the coil of wire and therefore lose definition at the extremes.
- Ribbon Microphones
Ribbon microphones consist of a thin strip of metallic foil suspended in front of a magnetic plate. Sound waves cause the foil to vibrate, producing fluctuations in the electrical current, creating the audio signal.This extremely sensitive configuration picks up a wide range of frequencies and produces an extraordinarily rich representation of the original sound. The trade off for this sensitivity is the delicacy of the mechanism. These ribbon microphones are also sensitive to physical impacts and therefore are not considered portable and can be easily damaged by power overdrive.
- Condenser Microphones
Rather than a vibrating wire coil, condenser microphones have a thin diaphragm and solid back plate which make up an electronic component known as a capacitor. As the diaphragm vibrates, the distance from the back plate to the diaphragm varies accordingly. This is known as fluctuating capacitance. It’s the fluctuation that produces an electrical current, resulting in the signal output.Condenser microphones are used for a variety of applications, making them an optimal compromise between the sound reproduction of ribbon microphones and the durability of dynamic microphones.As a result of the widespread application of condenser microphones, they have evolved into a number of subcategories including electret condenser, cardioid condenser and even dynamic condenser microphones. These specialized microphones represent the largest single category of microphones currently in use.
