Condenser microphones operate on an electro static principal rather than electromagnetic, as seen in dynamic microphones.
Condenser microphones use a pair of charged metal plates, one fixed and one movable (diaphragm), forming a capacitor. When a sound wave hits the diaphragm, the distance between the two plates changes. This produces a change in an electrical characteristic called ‘capacitance’. It is the variation of the spacing, due to the motion of the diaphragm relative to the back plate, which produces the electrical signal corresponding to the sound picked up.
To obtain a signal, condenser microphones require an electrical current to charge the plates. This is usually provided either by a battery or is sent down the microphone cable itself. This latter method is known as phantom powering. Most condenser microphones can operate with phantom power voltages ranging from 11 to 52 VDC.
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| The transducer of a condenser microphone |
There are three key advantages of a condenser microphone.
- The diaphragm assembly is very light compared to that of dynamic microphones, so the system is much more efficient at moving and is capable of capturing high frequencies.
- A flat frequency response and extended frequency ranges are easily obtained.
- They are often small in design.
There are however potential limitations using condenser microphones. There is a limit to the maximum signal level the electronics can handle, they are more complex than dynamic microphones and tend to be more adversely affected by extremes of temperature and humidity, and the electronics produce a small amount of noise.
In general, condenser microphones are more expensive than dynamic microphones but are more suitable for capturing the sounds of acoustic instruments and vocals due to their high sensitivity. They should be avoided when dealing with high sound pressures, such as that created from a kick drum. The sound produced from a condenser microphone can be described as being crisp, clear and detailed. Often the sound quality is better than that of a dynamic microphone.
Last Updated ( Monday, 23 June 2008 16:43 )
