Are you considering recording audio using a microphone or an instrument? You are going to need an audio interface. We explain what an audio interface is and why you need one in this guide.
One of the staple pieces of hardware you’ll need for music production is an audio interface. This device comes in several shapes and forms, but the ones you will most likely use are docks that you can place on your table or rack mounts if you have a standard-size rack.
To cut to the chase, you will need an audio interface to record professional-quality audio. In fact, some of them are also useful for midi recording as well. We will cover what an audio interface does and what benefit you will get by owning one. Furthermore, we will also provide you a guide to buying an interface at the end of this article. Let’s get right into it!
What Is An Audio Interface?
An audio interface is a device that connects your audio recording sources like mics, keyboards, guitars, etc., to your computer. It records audio in professional quality, which sets it apart from regular mic inputs on your PC. Similarly, it also connects to your speakers or headphones with quality sound.
Inside every audio interface, you will find two things: an audio-to-digital and a digital-to-audio converter. The first is a series of components that convert the audio information from your microphone or guitar into digital data that your computer can understand. The latter converts the digital audio from your computer to analog audio that your speakers produce.
Another crucial component of the audio interface is the preamp. Every professional audio interface contains a preamp chip that amplifies your mic or guitar/violin pickup volume. The better the quality of the preamp, the cleaner your audio recording will be.
Last but not least is the phantom power supply. It is a constant, clean DC 48v (±4v, usually) power supply that is used to power on a condenser microphone. It is not required for a dynamic microphone or guitar/violin pickup. Hence, you can turn the phantom power supply on or off as needed.
Why Do I Need An Audio Interface?
You need an audio interface to make professional audio recordings from microphones or instrument pickups, play noise-free audio from your studio monitors or headphones, and power your condenser microphones. There are also other functionalities that are available in all or select audio interfaces.
For example, some audio interface manufacturers provide features that free up computer resources, whereas others include multiple connectivities required for connecting older hardware like synths and keyboards to your computer. The following are the functions and features of an audio interface:
- Audio Preamplification
If you have ever tried recording audio from your computer’s mic inputs on the motherboard, you probably heard a noise that sounds like radio static mixed with your voice. That is an example of a bad preamp. In contrast, the audio interface’s preamp amplifies the signal captured by microphones or pickups with as little noise as possible.
- Digital-to-Audio Conversion
Every audio interface has a Digital-to-Audio (D/A) converter. What sets it apart from your computer’s internal D/A converter is that an audio interface prioritizes clean, unenhanced audio output over the bass and stereo-width boosted audio found in commercial laptops or phones. Unenhanced or flat audio is critical in music production.
- Headphone Amp
If you have purchased a pair of studio headphones, you probably noticed it has a specification called ohms (Ω) that typically ranges between 32 Ω (Samson SR850) to 250 Ω (Beyerdynamic BT-990). A higher value means more resistance, and thus, the headphone will require more power to function. An audio interface is equipped with a headphone amp to support a wide variety of headphones.
- Multiple Inputs And Outputs
Almost every audio interface manufacturer produces models with as little as a single input and a stereo output to as high as needed, like 18 inputs and 20 outputs. You will require a higher number of inputs and outputs if you intend to record bands or multiple hardware at once. Similarly, the outputs are useful if you wish to share headphones with your clients, typically while recording.
- Phantom Power
As we described earlier, the phantom power is a 48v DC power that powers a condenser microphone. It’s worth noting that a separate phantom power supply is also available for purchase, but they often introduce noise in your recordings. Hence, you should prefer an audio interface to power your condenser mics instead.
- Glitch-Free Performance
If you’ve been producing music for a while, then you’re all too familiar with the dreaded crackling and lagging when you add several synths despite the CPU being relatively underloaded. A slow audio circuit causes this issue. So, having a dedicated audio interface solves the problem.
- Latency-Free Monitoring
An audio interface lets you connect your mic or guitar and amplify the sound with zero latency/delay. This feature is called Direct Monitoring, and it’s a must-have while recording if you wish to hear yourself sing or play without latency.
For clarity, latency is the time duration between the moment you play a note or speak into the mic to the time when the computer picks it up and plays it back. It is controlled by a user-adjustable variable called Buffer Size. However, using a low buffer size (equaling low latency) will require a super-fast computer when there are many instruments or effect plugins in your project.
- MIDI Connectivity
If you own older keyboards or synthesizers, they probably have a MIDI connection with 5-pin jacks. Some audio interfaces like the M-Audio AIR 196 | 6 provide 5-pin MIDI ports. Note that dedicated 5-pin-to-USB adaptors are also available for purchase if your audio interface doesn’t support it.
- DSP Processing
A few audio interfaces like the UA Apollo Twin feature an internal DSP processor that can process effect plugins, releasing the load from the computer CPU. However, this feature is limited to the Universal Audio hardware and software environment.
How Do I Select An Audio Interface?
You should select an audio interface based on the number of inputs and outputs you need, the type of its connectivity, audio quality, and your budget. Furthermore, secondary factors like its design, build quality, driver support, and bundled software are worth considering as well.
If this is your first time purchasing an audio interface, you will want to make sure that you are getting one that fits your needs and gives the best possible results within your budget. There are many topics within the ones we just mentioned. So, this section will focus on the factors you need to consider when purchasing an audio interface:
In this section, we will talk about the build, connectivity, and other external factors of an audio interface:
- Number of Inputs/Outputs
For a home music producer, we recommend 2 ins/outs, but you can make do with a single input as well if your budget is low. However, if you wish to establish a commercial studio, look for 6 or more inputs. Similarly, if you work in surround sound for films/games, you will require 6 outputs for 5.1 and 8 for 7.1 surround sound.
Most audio interfaces are table dock designs, but there are many designed for rack mounting too. If you tend to travel or are just a home musician, look for portable dock designs, whereas commercial studios will benefit from the non-compact design of a rack mount.
There are four common kinds of connectivity to connect your audio interface to your computer: USB, Thunderbolt, FireWire, and PCIe. USB is the most common, whereas Thunderbolt is necessary for Mac computers. Similarly, FireWire is supported by some older motherboards. And last, a PCIe card requires the same slot as your graphic card, so it’s only applicable if you have an extra slot.
- Ports and MIDI
Most audio interfaces have both XLR (mic) and TS (guitar) ports for inputs, which are all you’ll need. However, some interfaces only have RCA outputs, whereas others have TS outputs.
Note that any of these can be converted to another using an adaptor, so it’s not a giant complication. So, if you manage to find an audio interface that fits the jacks from your speakers, it’s a hassle-free choice. Similarly, if you require a 5-pin MIDI port, look for that as well.
In this section, we will talk about some of the most significant information found under the specifications of an audio interface. You will learn what they mean and what to look for when selecting an audio interface.
The Equivalent Input Noise is a rating used to describe the overall noise performance of a mic preamp. It is a measure of how much noise is added by a preamp to the input signal from a mic. So, a lower value is better, and anything below -125 dBu is excellent. Note that an EIN of -130 dBu is lower, and -115 dBu is higher than -125 dBu.
- Dynamic Range
The mic input Dynamic Range is the difference between the strongest signal an interface can capture in comparison to the noise floor (EIN). It is the amount of headroom in recording without noise. So, we want this specification to be as high as possible. As a general rule, look for at least 110 dB of Dynamic Range or higher.
- Bit Depth & Sample Rate
Most audio interfaces have a bit depth of 24 bit, and that’s perfectly fine. However, the maximum Sample Rate can vary from 44.1 kHz up to 384 kHz. To clarify, the sample rate is double the highest frequency in a recording. So, a sample rate of 44.1 kHz has a maximum limit of 22 kHz as the highest limit, more than the human hearing limit of 20 kHz.
That fact raises the question of why a higher sample rate exists. Well, a higher sample rate is only necessary if you are recording audio and pitching/slowing it down for sound design. So, if you only intend to work on music, a sample rate higher than 48 kHz is entirely optional.
These are the least important factors for the average music producer. However, sometimes, they can be crucial to ensure that your interface is compatible with your computer and intentions, so make sure not to skip any of them.
While you should fare relatively well ignoring it, it’s a good idea to make sure that the manufacturer updates their drivers and supports the OS you use. You might prefer an older OS like Windows 7 or an alternative like Ubuntu 21. Make sure drivers are available for the one you use.
- Interface Controls
Each audio interface comes with software to control your interface’s sample rate and other settings. Here, you need to make sure your audio interface has a loop-back feature if you intend to stream the input and the computer’s output at the same time via video call, YouTube, Twitch, etc.
- Bundled Software
When you purchase an audio interface, you will also receive some software instruments and effect plugins. Some even include a DAW. For example, if you are after the DAW, Studio One, you might want to look into Presonus audio interfaces. Doing so can lower your cost significantly when upgrading your software.
If you need another description to help you select an audio interface, check this video:
Depending on what kind of uses you intend to make, we would recommend the following audio interfaces:
- Audient EVO 4
USB, EIN -128 dBu, Dynamic Range 113 dB
The EVO 4 provides one of the lowest EIN and remarkable recording quality. However, its single-knob control design with a plastic body might put off people who aren’t looking for portability. Still, the low price makes up for the few shortcomings.
- Behringer U-Phoria UMC202HD
USB, EIN -129.1 dBu, Dynamic Range 110 dB
The UMC202HD is one of the cheapest audio interfaces with excellent quality, two audio inputs, and one of the lowest EIN. It also supports up to 192 kHz sample rate, and its full-metal build gives it a sleek appearance.
- Focusrite Scarlett Solo 3rd Gen
USB, EIN -128 dBu, Dynamic Range 111 dB
Many people swear by Focusrite for their fabulous noise performance and preamps. The Solo model comes with a single mic input, so it’s perfect for a musician on a budget looking to make professional-quality recordings.
- Focusrite Scarlett 2i2 3rd Gen
USB, EIN -128dBu, Dynamic Range 111dB
The Scarlett 2i2 3rd Gen is our most preferred in this section for its affordability, low EIN, and great-sounding preamps. However, another thing worth considering is its stereo Direct Monitoring feature, making it an excellent choice for singers and guitarists who enjoy practicing listening to themselves.
- M-Audio AIR 192 | 6
USB, EIN -128 dBu, Dynamic Range 104 dB
The AIR 192 | 6 is an audio interface with quite impressive EIN and a decent Dynamic Range. It features two mic inputs and two outputs. It’s most desirable if you wish for 5-pin MIDI connectivity.
- UAD Apollo Twin
Thunderbolt 3, EIN NA, Dynamic Range NA
The Apollo Twin Mk II is the most expensive of the three here, and it provides some excellent features. The biggest is its internal DSP processor for UA effect plugins. And its preamps are modeled after classic gear, making it one of the best-sounding audio interfaces.
Commercial Studio/Sound Designer
- Focusrite Scarlett 18i20
USB, EIN -128 dBu, Dynamic Range 111 dB
The Scarlett 18i20 has long been used in professional studios, and people praise it for its reliability and impeccable recording quality. If you are involved in band recordings, film/game sound designing, or broadcast mixing, its 18 input and 20 outputs will serve you well.
- PreSonus Studio 1824c
USB, EIN -128 dBu, Dynamic Range 110 dB
PreSonus provides one of the cleanest audio recordings we’ve heard yet from this audio interface. 18 inputs and 24 outputs make it capable of handling pretty much any kind of requirement in a professional studio environment.
- M-Audio ProFire 2626
FireWire, EIN NA, Dynamic Range 109 dB
The ProFire 2626 is genuinely a well-thought-out piece of hardware for productions in films and games. It has 26 inputs and 26 outputs, ganged volume controls for up to 7.1 surround, and excellent recording quality.
Note that many of the high input/output counts will require you to have S/PDIF compatible hardware to use them all.
In conclusion, an audio interface is a device that allows you to make professional-quality audio recordings and also provides many other benefits. Even if you aren’t recording audio, having an audio interface will make your computer perform much better by lowering latency.
Selecting an audio interface has many variables, but the ones that matter most are your budget and input/output requirements. It’s worth keeping in mind that a small change in EIN, Dynamic Range, or any other specification does not make an audible difference. Hence, don’t sweat over a decibel’s worth of noise performance for something much more relevant, like compatibility with your computer.
If you are still unsure where to start your research even after reading our guide, try checking out the links to the various audio interfaces we have in our Recommendation section. Each of them was hand-picked after thorough analysis, so you can be sure never to land on a wrong choice. More than that, just getting started somewhere will make it much easier for you to learn what to expect. We hope this article helped you understand and select an audio interface.
K. M. Joshi is a multi-award-winning composer and sound designer, specializing in film, game, and TV audio. He enjoys making cinematic music, rock, blues, and electronica.