Condenser Microphones: Facts And Information
Condenser microphones are also know as capacitor microphones. What does this mean and why is it important?
Condenser microphones have a diaphragm that acts as one plate of a capacitor and the vibrations produce changes in the distance between the plates. The plates are biased with a fixed charge, the voltage is maintained across the capacitor plates which change with vibrations in the air, according to the capacitance equation… So much for the scientific and mathematical information. For those of you who can decipher the above information, I salute you. For the rest of you we will continue on a less academic level!
All microphones have two determining characteristics. These two characteristics are operating principle and pickup pattern. The pickup pattern is what determines from which direction the microphone will capture the sound. When condenser microphones are working properly the output from the capacitor is a very small electrical signal. This electrical signal is so weak it needs to be amplified. The amplification is built right into the microphone but it still needs electricity. The electricity comes from a battery or from the "phantom power" provided through the microphone cable or a microphone mixer. The condenser diaphragm is so small that less acoustic energy is needed to make it vibrate. This means most condenser microphones are more sensitive than dynamic microphones.
Condenser microphones can be quite expensive and as you can see from the information above they require a power supply. Most people who use condenser microphones in studios or in laboratories use the "phantom power" type of power supply provided by microphone inputs because of the high quality sound that is produced.
A fairly new type of condenser microphone is the foil electret microphone. These condenser microphones were invented at Bell laboratories in 1962 by Gerhard Sessler and Jim West. Condenser microphones of this variety have been around since the 1920's but were very impractical. They are now the most common of the condenser microphones. The electret condenser microphones are used for high-quality recording and as lapel microphones. They are also used in small sound recording devices.
At one time electret condenser microphones were thought of as low quality and low-cost. The best of these condenser microphones now rival capacitor microphones in every way except for the low noise component. These condenser microphones feature long-term stability and the ultra-flat response needed for a measuring microphone. Electret microphones do not need a polarizing voltage and usually contain an amplifier that is integrated and does need power.
There are different kinds of condenser microphones and hopefully this article has given you some helpful information that can provide guidance if you are considering this type of microphone.