Just because phantom power sounds mysterious, that doesn’t mean it is. Phantom power is just one way that you can activate a microphone. Some mics need phantom power to work, but it can also damage or break other mics. So, do wireless mics need phantom power?
Wireless microphones don’t need phantom power, as they rely on battery power to work. In fact, supplying your wireless mic with phantom power can fry the power and acoustic mechanisms and overload the battery. Only wired condenser microphones require phantom power to work.
This article will discuss how phantom power works and what kinds of microphones you should and shouldn’t use phantom power with. I’ll also offer some tips to avoid damaging your mics and answer some questions you may have along the way.
Microphones & Phantom Power
All microphones are transducers. That means that they turn acoustic energy into electrical energy. Some microphones need an external power source to complete this transformation, but others can do so automatically.
Microphones that require phantom power — or an electrical circuit — to transmit sound are called active microphones. On the other hand, the types that don’t need a phantom power source are called passive microphones.
What Is Phantom Power?
Phantom power is a direct current (DC) of electricity sent down a microphone cable. Phantom power earns the name “phantom” because it seems invisible and doesn’t require a power adaptor or electrical outlet to work.
Many mixers, sound interfaces, and preamps have a built-in phantom power source, but not all do. Phantom power is a way to activate active microphones that need a direct current of electricity to function. However, wireless microphones don’t need this extra energy.
How Does Phantom Power Work?
Phantom power usually runs between 9 and 48 volts, and each active microphone needs a different voltage to work with it.
Still, 48 volts is the most common voltage. When looking for a phantom power setting, your mixer, audio interface, or preamp will usually read 48V or P48, which stands for 48-volt or phantom 48.
It works with electrons sent straight from your mic to the amplifier or sound system, unlike other power systems that use an alternating current. With this direct current, phantom power gives your active microphone the energy it needs to amplify acoustics and send sound waves straight back to a speaker, mixer, or amplifier.
Phantom power sends your acoustics through a balanced cable, which reduces white noise and humming. This cable — usually an XLR cable — sends your acoustics to a speaker or sound system while cutting out white noise and resistance humming, eliminating the need for a bulky power system or external amplifier. Because phantom power uses an XLR cable, most wireless mics don’t need phantom power at all.
Phantom power also lowers the impedance of acoustics. When your audio has a high impedance, it generally has more noise or humming than low-impedance sound waves. That’s because high-impedance signals need a lot of gain to get to a speaker or amplifier.
Since active microphones usually emit high impedance signals, using phantom power can give your acoustics a clearer, more balanced sound when they are amplified or recorded.
Why Wireless Mics Don’t Need Phantom Power
Since most wireless mics run on battery power, they don’t need phantom power at all. Wireless microphones often have an internal power supply that eliminates the need for extra equipment, which is why they’re so popular and convenient.
There are many different types of wireless mics. Still, most of them have all of the equipment they need to convert impedance, power audio outputs, and reduce noise built into their casings.
Even wireless condenser mics have an internal preamp that converts the audio into a direct current. This built-in preamp works just like phantom power. But it doesn’t require an XLR cable or mixer to adjust impedance and amplify acoustics.
Wireless microphones work by processing acoustics on their own. Then, they turn the acoustics into a radio transmission that gets read by a receiver connected to a speaker.
So, since wireless microphones require no external power source or audio-adjusting equipment, using phantom power on them can add interference and potentially even damage the microphone. When working with a wireless microphone, never hook it up to an external power source, even phantom power.
Can Phantom Power Damage a Wireless Microphone?
Phantom power only works with active wired condenser microphones. When you use phantom power with a passive, wireless, dynamic, or electronic microphone, the additional energy can cause a short in the system or damage the amplifying mechanisms.
Since wireless mics have a built-in power system, usually in battery form, adding another power source can fry the power and acoustic mechanisms in the microphone. Sometimes, this can ruin the entire microphone’s audio reading system or overload the battery.
But most of the time, it’ll only add extra noise to the audio output or muffle sounds. So, it’s best to only use phantom power with mics that are specifically compatible with it.
Another type of microphone that phantom power can damage is a ribbon microphone, even if it has an active system. Usually, a ribbon microphone only reacts badly with phantom power happens if you misconnect the cables or if your microphone is already damaged or shorted. Still, sometimes other factors can break the microphone.
Say the ground wire in your XLR cable is miswired or already shorted. In that scenario, plugging your ribbon microphone into phantom power can overload its electrical system, damaging the ribbon entirely. Voltage spikes, electrical outages, and worn-out connectors can also ruin your ribbon microphone when using phantom power.
So, most audio technicians recommend that you never use phantom power with ribbon microphones since the voltage can overexert the ribbon, stretching it too much. In some cases, the ribbon may tear, reducing the sound quality of your mic or potentially breaking it permanently.
What Microphones Need Phantom Power?
For the most part, only wired condenser microphones need phantom power. Inside a condenser microphone, the diaphragm covers several thin metal plates. These thin metal plates need an electrical charge to convert and amplify sound.
So, how does a condenser microphone work with phantom power?
Phantom power creates static electricity, which charges the thin metal plates and the diaphragm in condenser microphones. When you speak into a condenser microphone, the diaphragm vibrates against the plates, and the static electricity amplifies the sound waves. That’s why condenser microphones need a direct current to work properly.
Condenser microphones also emit high impedance sound waves. These waves have to be converted to a low-impedance signal to go through an amplifier. Phantom power can reduce the impedance, making the sound much clearer when you feed it into a mixer, amplifier, or PA system.
So, wireless microphones don’t need phantom power to work. Wireless microphones have a built-in power supply. They also include all of the mechanisms they need to lower the impedance, amplify sound, and transmit it to a mixer or speaker.
Should You Turn Off Phantom Power When Connecting a Mic?
You should always turn off phantom power when you connect or disconnect a mic. When you leave phantom power on and connect a mic, the energy causes a loud pop that could easily damage the delicate mechanisms in a microphone or a speaker.
That can also happen when you disconnect a mic, so always start phantom power after connecting your microphone.
Wireless microphones do not require a phantom power source, and using one on them can damage the microphone. Only condenser microphones need a phantom power source since they need static electricity and an impedance converter to balance their audio output.
When using a wireless microphone, never plug it into an outside power source since this can damage the audio reading mechanism or overload the battery.