Dynamic and Condenser Microphones
Both dynamic and condenser microphones have a membrane that vibrates in accordance with the air movement around it, also known as the sound. The microphone must then transform this membrane movement from acoustical energy into electrical energy. This is where the transducer comes into the picture and each type of microphone has different transducer properties.
When considering a two way radio transceiver microphone it is important to know whether it uses an electret or dynamic cartridge. The Cobra 29 LTD, for instance, uses a mic with a dynamic cartridge. If you connect a mic with an electret cartridge to this radio, it will work, but the audio will be very faint on the receiving end.
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Dynamic Microphone
Typically a dynamic microphone will work without power to the microphone. You can put a dynamic microphone directly on an oscilloscope and watch the waveform. Also most of the time the dynamic microphone is less expensive than a condenser microphone.
Basically a microphone works by converting sound into an electrical signal by means of electromagnetism. They fall into two categories, moving coil and ribbon microphones. The most common type of dynamic microphone is the moving coil microphone, like those used with two way radios such as Citizen Band radios.
Ribbon microphones work by the same basic principle of electromagnetic induction. However, instead of having a membrane and a coil, a ribbon transducer uses a narrow strip of extremely thin aluminum foil. This type of microphone is somewhat fragile when compared to the moving coil type.
Most dynamic microphones are low impedance, however, there are older dynamic microphones that are high impedance, or hi-Z. For example, the Sure 585SA is a hi-Z dynamic microphone.
Condenser Microphone
This type of microphone requires power applied to it for it to work. In general, condenser microphones exhibit a higher sensitivity than dynamic microphones. Condensers can, in general, handle extremely high sound pressure levels.
Types of Condenser Microphones
There are two types of condenser microphones: a permanently biased condenser, usually called an electret condenser, and an externally biased condenser, usually called a true condenser.
- electret condenser
- true condenser
The majority of condenser microphones are electret condenser microphone so typically when someone says condenser or electret they are talking about the same thing.
Examples
- Cobra 4-pin hand mic - Dynamic microphone. There's no voltage on the mic element.
- Icom SM-6 desk microphone - Electret microphone. There is voltage on the mic element.
- D104 original Hi-Z microphone - Dynamic microphone. It is a power mic with its own internal amplifier, however, there is no voltage on the mic element.
