Tuesday, October 23, 2012

The Difference Between Condenser and Dynamic Microphones


I used microphones for quite awhile before I figured out there are two different popular types of microphones available, plus I never knew why I would want to have phantom power on my mixing board. Now I know, and I thought I would try to summarize the differences between condenser and dynamic microphones for you all. Of course, a lot of my friends are smarter about these things than I am, so if I get something wrong here be sure to let me know.

The fundamental difference between condenser and dynamic microphones is the method in which they receive and pass on sounds:

∙A dynamic microphone operates via induction. This means that it uses a coil and a magnet to produce an electrical signal (inducing a voltage). The microphone has a diaphragm inside that is attached to a coil. When sound pressure waves hit the diaphragm it vibrates, and the coil moves back and forth across the magnet, producing an electrical signal which is sent through the microphone cable to the mixing board. This means that they do not require a battery or external power to operate. Dynamic microphones are the more popular option as they are generally not very expensive (many are under $100) and they are well-suited for most every task. They are not complicated and do not have many moving parts, making them durable and thus ideal for live sound applications. Also, due to their design they can cope with high volume levels, such as from brass instruments or when miking speaker cabinets.

∙A condenser microphone operates via conduction. This means that there are two plates (or diaphragms) inside the microphone, with a small space between them that acts as a capacitor (or condenser) that stores electrical energy. When sound pressure waves hit the front plate it moves, changing the distance between it and the back plate. This will allow the electrical current to charge or discharge the capacitor, sending an electrical signal to the mixing board. This process requires an electrical power source to be used, either in the form of a battery, or more commonly from phantom power that is supplied from the mixing board. Condenser microphones are very sensitive, making them ideal for the studio environment. Of course they are more complicated than dynamic microphones, which makes them more expensive ($300 and up) and fragile. If you combine this with their inability to handle high volume without distorting, makes them ill-suited for most live sound work.

This might be a good time to talk about phantom power. This is 48 volts of direct current (at 2 to 10 mA) that is applied through the two signal lines of a balanced XLR connector and referenced to pin 1, which is ground. This power is usually supplied the mixer, PA system or other recording equipment. Dynamic microphones do not use phantom power but are not damaged if phantom power is put through them (it may cause a hum, though). And always keep in mind that you should never ever turn phantom power ON before plugging a microphone in.

Anyway, I hope this explanation helps. Writing about things like this certainly helps me to collect my thoughts better!