What is phantom power and why does my microphone need it?

Condenser microphones have electronic components that need a power source. In the music and audio recording context, we use phantom power.

Phantom power is 48 volts of DC (direct current) electric power. It's transmitted through the XLR cable from the audio interface or mixer to the microphone.

Phantom power is transmitted in the same cable as the audio signal without affecting the quality of the audio signal.

The power is transmitted on pins 2 and 3 of the XLR connectors. Pin 1 has no power.

A condenser microphone is an electric capacitor. When sound waves hit the membrane, they are transformed into an electrical signal. Power is needed to form this capacitor. These externally polarized microphones need phantom power to work. 

Phantom power is needed to power the electrical components of condenser microphones so they can work.

So, without phantom power, there is no capacitor, and without a capacitor, a condenser microphone cannot transform sound waves into electrical signals. That is the basic function of a condenser microphone. To learn more about the topic, check out the blog post How does a microphone work.

However, some microphones have advanced features like a display and other electronic components. They also rely on phantom power.

In the microphones above, you can see displays that light up and buttons to change functionality. All of that is powered via phantom power. It’s pretty remarkable how much you can do with only 48v.

One of our most advanced microphones is RAY. Its unique features make recording easy and fun. It has a built-in autofocus function, so your voice is always in focus. It automatically adapts the audio signal to your distance from the microphone. You can also automatically mute RAY at a certain distance. 

These powerful features use more electrical components than most other XLR microphones. It was a complex challenge to accomplish all this using only 48 volts of phantom power. 

When working with audio, you have definitely come across the term P48 or 48V printed on audio equipment, mainly on audio interfaces or mixing consoles. 

Audio interfaces and mixing consoles provide phantom power.

These devices provide phantom power as they are meant for use with microphones, so you can easily use them with your condenser microphones.

Some audio interfaces have a physical button to toggle phantom power. With more modern interfaces, you can also use software to toggle phantom power on and off.

In general, dynamic microphones do not need phantom power to work.

There are dynamic microphones with extra features that need phantom power. These are usually called active dynamic microphones. "Active" describes the fact that they need energy to work, as opposed to "passive" devices, which do not need external power to work. These extra features could be signal boosts or low-cut filters, for example.

Active devices need power - passive devices do not need power.

Other microphone types usually do not need phantom power. Most ribbon microphones are passive microphones and don't need phantom power, in most cases, it's quite the opposite. But more on that later.

Condenser tube microphones or USB microphones get their power from other sources. USB is bus-powered, and tube microphones need their own power supply to work.

The short answer is yes, it can. But the chances are very low that it will affect your setups. In the majority of cases, you are safe.

Modern condenser and dynamic microphones cannot be harmed by phantom power.

Phantom power could potentially harm and even destroy older ribbon microphones. To be on the safe side, never turn on phantom power while using them.

Even though phantom power cannot harm your other microphones, it is good practice to turn off phantom power before unplugging or plugging them in. If you don’t turn off phantom power, you may hear a loud pop sound in the signal.

Other than microphones, some audio devices also need phantom power to function. These devices are active and need power for their electrical components to work.

For example: inline signal boosters, or DI boxes for instrument recording.

Other instruments or XLR devices usually do not require phantom power.

This general technology was invented to power telephones in 1919. Later, the 48V phantom power that is now widely used in music production was used. In 1966, the Norwegian Broadcasting Corporation, NRK, ordered new microphones from Neumann GmbH. They wanted to utilize the technology to power the microphones through cables rather than an external power supply for their new setup.

They already had 48V power available in their studios for their emergency lighting systems, so they used the same power for the microphones as well. This arrangement was later formalized in a DIN standard and has been used ever since.

Before phantom power, condenser microphones needed an external power source to function. Now that you don’t see the power source anymore, the name “phantom power” was commonly used for the technology.

I hope this blog helped you understand what phantom power is and how it is used in recording. Should you have any questions or want to chat with us, feel free to contact us through email or on social media.