What Is an Audio Interface and Do I Need One?
Updated: 19 hours ago
I've had plenty of reasons to use audio interfaces over the years. I'm a musician, streamer, DJ, voice actor, audio engineer, and I've even hosted my own podcast. At this point, an audio interface is one of those pieces of equipment that I use pretty much every time I sit down at my computer.
But if you've never needed one before, the little box full of knobs and strange-looking ports can raise a pretty obvious question:
What does an audio interface actually do, and do you really need one?
An audio interface connects microphones, instruments, headphones, speakers, and other audio equipment to your computer. One of its most important jobs is converting analog audio, like your voice or the signal coming from a guitar, into digital information your computer can record and process.
It also works in the opposite direction, converting digital audio from your computer back into an analog signal you can hear through headphones or speakers.
In simple terms, an audio interface is the middleman between your audio equipment and your computer.
What Does an Audio Interface Actually Do?
Think of an audio interface as a hub for your audio setup.
Your computer probably doesn't have an XLR microphone input, a 1/4-inch instrument input, dedicated studio monitor outputs, a professional headphone connection, and physical gain controls built into it.
An audio interface gives you those connections in one piece of hardware and then connects the whole setup to your computer, usually through USB or USB-C.
That means you can plug a microphone into the interface, connect your headphones, adjust your microphone gain with an actual knob, and send that audio into recording, streaming, or voiceover software on your computer.
For me, that physical control is part of the appeal. I don't always want to dig through software just to adjust something as basic as my microphone gain or headphone level. Having those controls sitting on the desk makes managing audio much faster.
Do You Need an Audio Interface?
Not everyone does.
If you're using a USB microphone that connects directly to your computer and you're happy with the results, you may not need an audio interface at all.
That's one of the biggest differences between recording now and years ago. USB microphones have made it much easier to get decent audio without building an entire recording setup.
But an interface starts making a lot more sense when you want to use professional microphones, XLR connections, instruments, studio monitors, or multiple audio sources.
You may want an audio interface if you're:
recording with an XLR microphone
recording vocals or instruments
connecting a guitar, keyboard, or other instrument to your computer
doing voiceover work
streaming with a more advanced audio setup
recording a podcast with multiple microphones
producing music
connecting studio monitors or professional headphones
building a home recording studio
I use interfaces for several of these things, including voice acting, streaming, music, DJing, and everyday computer audio.
Do You Need an Audio Interface for an XLR Microphone?
Usually, yes.
An XLR microphone can't simply plug into the USB port on most computers. The audio interface gives you the XLR input and converts the microphone's analog signal into digital audio that your computer can use.
The interface also contains a microphone preamp. That preamp gives you gain, allowing you to bring the microphone's signal up to a useful recording level.
If you're using a condenser microphone that requires 48V phantom power, many audio interfaces can provide that as well.
That's why you'll often see XLR inputs, gain knobs, and a button labeled 48V sitting together on an interface.
The Focusrite Scarlett 18i16 4th Gen is built for setups that need more room to grow. With multiple inputs and outputs, it can handle microphones, instruments, monitors, and other studio gear without forcing everything through a basic two-input setup.
This bundle also includes headphones, a pop filter, two 15-foot XLR cables, and recording software, making it a more complete option for musicians, podcasters, streamers, voice actors, and home studios that need to connect multiple pieces of audio equipment.
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What Can You Plug Into an Audio Interface?
It depends on the interface, but common connections include:
XLR microphones
guitars and basses
keyboards and synthesizers
DJ equipment
studio monitors
headphones
mixers and other line-level audio equipment
Some interfaces use combination inputs that can accept either an XLR cable or a 1/4-inch cable through the same input.
This is one reason an interface can become the center of a recording setup. Instead of expecting your computer to have connections for every piece of audio equipment you own, you connect that equipment to the interface and connect the interface to the computer.
Why Do Audio Interfaces Have a Headphone Jack?
The headphone connection isn't just there because your computer ran out of ports.
Many audio interfaces allow you to direct monitor your microphone or instrument. That means you can hear the signal coming into the interface without waiting for it to travel through your computer and recording software first.
This can eliminate or greatly reduce the distracting delay known as latency while you're recording.
For voice acting and vocal recording especially, being able to hear yourself clearly in your headphones while you perform is extremely useful.
Do Streamers Need an Audio Interface?
Not necessarily.
A streamer using a USB microphone can build a perfectly functional setup without one.
But if you're using an XLR microphone, studio monitors, professional headphones, multiple audio sources, or a more complicated routing setup, an interface gives you much more flexibility.
It also gives you physical control over important things like microphone gain and monitoring levels without requiring you to hunt through software every time you need to make an adjustment.
Audio Interface vs Mixer: What's the Difference?
An audio interface and a mixer can overlap, but they aren't automatically the same thing.
An interface is primarily designed to get audio into and out of a computer while handling conversion, inputs, outputs, monitoring, and recording.
A mixer is designed primarily for combining and controlling multiple audio signals.
Some modern mixers include USB audio interfaces, which means one device can perform both jobs. If you're shopping for either one, check the specifications instead of assuming that every mixer can send separate audio channels to your computer.
Can an Audio Interface Work Without a Power Adapter?
Some can.
Many smaller USB audio interfaces are bus powered, meaning the computer provides power to the interface through its USB connection.
That's incredibly useful for portable recording.
With the right setup, I can take a charged laptop, connect a bus-powered interface, plug in my microphone, and record without needing a separate wall adapter for the interface. If the interface provides phantom power, it can also power a compatible condenser microphone from that same setup.
For voice actors, musicians, podcasters, and other creators who sometimes need to record away from their main studio, that portability can be a major advantage.
What Should You Look for When Buying an Audio Interface?
Start with what you're actually connecting to it.
If you're recording yourself with one microphone, you probably don't need an interface with eight microphone inputs. If you're recording several people or instruments simultaneously, two inputs might become limiting very quickly.
Pay attention to:
number of microphone and instrument inputs
XLR and 1/4-inch connections
phantom power
headphone outputs
direct monitoring
computer connection type
number of speaker/line outputs
bus-powered vs externally powered operation
You don't necessarily need the most expensive interface. You need one that has the right connections and features for the way you work.
I've owned quite a few interfaces over roughly 15 years of recording. The ones that have stayed in my setup the longest have been my Focusrite Scarlett interfaces. I still have an older-generation Scarlett that works, along with a newer one that has become part of my current setup.
For me, that's part of the value of buying a solid interface. It isn't something I'm constantly replacing. Most of the time, it sits on my desk, does its job, and quietly becomes the center of everything audio-related.
If you're only using a USB microphone, you may not need an audio interface yet. But once you start working with XLR microphones, instruments, studio monitors, multiple audio sources, or more advanced recording setups, you'll quickly understand why that little box full of knobs ends up sitting in the middle of so many studios.
The M-Audio M-Track Duo is a compact 2-channel USB audio interface with two combo inputs for connecting XLR microphones, instruments, and line-level audio. It includes phantom power for compatible condenser microphones, direct monitoring, and separate controls for managing your recording and headphone levels.
It's a practical option for streamers, podcasters, musicians, and other creators who want to move from a USB microphone to an XLR setup without spending a lot on their first audio interface.
As an Amazon Associate I earn from qualifying purchases.
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