How a Condenser Mic Works

How A Condenser Mic Works

Were you ever curious and thought “how does a condenser mic work”? In this post, we will be going over how a condenser mic works.

How it works

Condenser microphones are also called capacitor microphones because of how they are designed. Its a very thin membrane that converts acoustic energy into an electrical signal. (pretty neat right?). The capacitor is actually 2 metal surfaced plates thats suspended above a back plate. They are very close to each other.

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This membrane is very light and very thin and it has to be conductive. In most instances, you will see gold on it to be conductive and then it needs a charge (power). This charge comes from an external power supply which we call “phantom power”. Phantom power is a 48-volt signal that comes from a pre-amplifier (preamp) or an audio interface. This power is passed through the XLR cables and into the condenser microphone.

a condenser microphone
How a condenser mic works

If the microphone did not have any external power source going thru it, the microphone would be very very quiet. The nature of the condenser microphone needs the signal to be boosted because the voltage with the capacitor plates does not produce any current. Another name for these kinds of condenser microphones are “externally polarized condenser microphones”.

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Another way for a condenser microphone to have power is from a permanent charge and we call these “electret microphones”. With an electret microphones, electricity is supplying continuous power to the condenser capacitor. Usually in these instances, there is an on-board battery. Examples of Electret microphones are lavalier mics, and smaller microphones such as ones used in phones.

condenser mic plugged into computer
Condenser mic

As the Diaphragm moves, the capacitance of the circuit changes which imparts a small electrical output. The output is very small and must be amplified within the microphone. Most condenser microphones features an FET impedance converter which is battery or phantom powered

Conclusion on how a condenser mic works

There you have it. Now you know how a condenser microphone works. With this knowledge you can troubleshoot issues and you can use this to your advantage when choosing a microphone that works for you.

RELATED – How to Setup a Condenser Mic

For more info checkout this helpful youtube video –

Here is another helpful link as well –

We hope this was helpful. Leave a comment and let us know what else you learned from condenser microphones!