When starting to learn about recording, you might find yourself bombarded with terms that you find a little confusing. Looking at microphones, some may be described as “needing an audio interface” and others might be described as “needing phantom power”. Therefore, it is easy to assume they are the same thing. Is this the case?
No, phantom power is not the same as an audio interface, they are different things.
Phantom power is the name given to a power source that runs to a microphone in order for it to work. Microphones with active circuitry require power to be sent to them. In order to generate the electronic signal, a small charge needs to go to the diaphragm and backplate. This charge is often provided by a phantom power mode on an audio interface. This is where a lot of the confusion comes from. The two may go hand-in-hand in some respects, but they are not the same thing.
Understanding What An Audio Interface Is
An audio interface can do much more than just provide phantom power for a microphone.
The main purpose of USB audio interfaces is to take an audio input (or multiple audio inputs) from a microphone or instrument and turn it into a signal that can be transferred via USB, directly into your computer.
You can then use this in a Digital Audio Workstation (DAW) or even to allow you to use a microphone in Zoom calls for example.
Audio Interfaces Often Have Phantom Power Built-In
To ensure that the audio interface can “communicate” with as many microphones as possible, many have a phantom power setting. This usually comes in the form of a button on the channel strip that tells the interface to send power to the mic.
Sometimes this isn’t labelled ‘phantom power’ and may simply be labelled ’48v’ on many interfaces.
The audio interface itself will either be drawing power from the mains using an adapter, or some USB interfaces can use the power sent from your USB port.
Phantom power is sent as a D/C current, usually at 48 volts (hence sometimes being labeled simply 48v). This D/C current actually travels through the instrument cable, usually an XLR cable.
This is why it is called “phantom” power, as it doesn’t look like any power is being transferred, and there is no specific cable for it. On an XLR, the current travels through pins 2 and 3, while pin 1 is the “ground”.
An Audio Interface Does Much More Than Provide Phantom Power
An audio interface is not just for sending phantom power to a microphone and are an essential item in any home music studio. What are some of the other functions of audio interfaces?
Improving Recording Quality
A regular computer sound card isn’t built specifically for music production. They are made to be multi-functional. However, a audio interface has a soundcard within it specifically designed for audio production.
Not only that but they have built-in pre-amps which improve the tone of your instruments and microphones.
You may have experienced latency issues in the recording process, and if so you will know how frustrating it can be, making recording almost impossible!
Latency is a gap between when you play an instrument and when it is picked up by whatever you are recording it with.
Audio interfaces minimise and practically eliminate latency in most cases. Improving your recording experience and reducing that frustration!
Adjusting and Mixing Input Levels
Many can cope with multiple incoming audio sources, so you can use them as a small mixer for multiple microphones.
For example, if you want to record guitar with one microphone and your vocals with another, an audio interface with enough inputs can cope with this. Knobs or sliders for level setting allow you to make your inputs louder or quieter to suit.
Multiple Inputs and Outputs
Most audio interfaces come with multiple inputs and outputs.
This often includes a headphone out and a line out so you can montor recordings live through studio headphones.
Monitor speaker outputs so you can monitor what you are inputting as well as have an easy connection point for studio monitors.
What Are Some Other Sources of Phantom Power?
Although an audio interface is probably the simplest way to get phantom power to a microphone, there are other alternatives.
Phantom power is usually sent to the mic via an audio interface, but can also be sent via a mixing desk. This is useful for larger band recordings if you still want to use condenser microphones.
In some cases, microphones have space for batteries which can be used to provide phantom power without the use of a cable. This is especially useful for wireless usage.
Phantom Power and DI Boxes
There are DIs and preamps on the market that can use phantom power. A DI box boosts the signal of an instrument and may be paired with your audio interface. L.R. Baggs and the Para DI are two boxes that don’t always work with small voltages sent from most mixers, so the use of phantom power can be useful for this purpose.
A DI may be used to boost the signal of instruments like guitars or bass guitars, and digital pianos, which may otherwise need an amplifier to reach a loud enough volume.
Which Mics Need Phantom Power?
There are three main microphone types you are likely to come across. Dynamic, Condenser and Ribbon. To learn the basic differences check out this quick summary article on the subject.
It is important to explain that not every microphone needs phantom power. Ribbon microphones do not need phantom power in order to work. If you connect a ribbon mic to your audio interface, you actually need to ensure that phantom power is off, or risk damage to the microphone.
Dynamic mics usually won’t be damaged, but they do not need phantom power. If you are using an instrument’s output, definitely avoid using phantom power.
It is true condenser microphones that need voltage run to them, which helps to polarize the mic’s transducer and to create an audio signal. This is usually between 12-48V, and 48V has become the industry standard. So pretty much all condenser mics need phantom power to work.
Do USB Condenser Mics Need Phantom Power?
Yes all condenser mics need phantom power as that is how the technology works. But USB condenser mics get their power from the USB cable and so don’t need an audio interface to provide the phantom power.
It is a good idea to check any microphone you plan to use to find out the power requirements.
Summary – Is Phantom Power The Same as an Audio Interface?
In summary, the two are very different things, and phantom power is actually a feature of the audio interface, rather than an alternative.
Many microphones require a voltage run to them via “phantom” power to operate. An audio interface usually has a setting to allow this, but it is not the only way to get phantom power. Some mixing desks do the same job, and some mics even use batteries for this purpose.
For many people who need phantom power, an audio interface is the easiest method.