Magroove Magroove
Free Distribution.
Free Store with
custom merch.
No hidden fees.
Not today

What is an audio interface? What does it do? Do I really need one?

July 03, 2019 • 7 min read

If you're setting up a home recording studio, you've probably asked yourself this question: What is an audio interface , anyways? Do I really need one? An the probable answer is: Perhaps. An audio interface isn't necessary for your when you're beginning your music production studies, for instance. Also, It may not be crucial when downloading your first DAW (Digital Audio Workstation) or trying your hand at capturing and editing audio. However, purchasing an audio interface should be one of your first investments when attempting to bump the quality of your production. Not only that, it also makes your life easier in studio. what is an audio interface article featured image - which should I choose and why?

What is an audio interface?

An audio interface, also known as sound card, is a hardware device aimed mainly to convert AD and DA. In other words, it changes an analog signal ("A") from mic/instrument to digital signal ("D"). In other words,  "Analog to Digital" or "AD". Not only does convert AD, as it then converts the digital signal from the pc to analog signal ("DA"). Reasons for owning an audio interface:
  • Optimizing CPU.
  • Providing Phantom Power to mics that need it.
  • Pre-amp the audio signal.
  • Supply mic and instrument inputs.
  • Supply studio monitors and headphones outputs.

Why is an audio interface important?

A computer's motherboard manages different data all at once. When the audio interface is doing AD or DA conversion, it frees the motherboard from this task, optimizing it. Using a sound board allows for better quality of the recording, since they support the better sample rates, for instance.
Focusrite Audio interface

Audio Interface

ASIO Driver

It's extremely important to be aware that most DAWs use a driver, the ASIO (Audio Stream Input/Output). A driver is a computer program which controls a particular hardware device. ASIO, controls audio recording devices. However, ASIO only runs on audio interfaces. As far as a PC goes, its native audio drivers, like MME and Direct X, weren't developed for producing music. AS a matter of fact, even if your DAW recognizes the audio driver, there will be a lot of latency (delay as it reproduces recorded or edited sounds.) In 2003, ASIO4All was launched for PC. This driver was created to lower the latency and simulate soundboard ASIO. Thus, it could be recognized by DAWs. For a MAC, the audio driver, Core Audio, has much less latency then the drivers available for Windows. In theory, its quality and latency allow for satisfactory recording, but you miss out on all the resources an interface has to offer. That being said, there is nothing like running a DAW with their own driver. It doesn't matter what operating system you're using, ASIO guarantees the best audio processing and low latency for recording.

What is an audio interface for if I'm only recording voice or one instrument at a time?

Either with a PC or a Mac, using your computer's mic line-in, isn't recommended to record music. They have a sort of pre-amp, but their impedance isn't adequate and they can't provide Phantom Power. Most computers Mic-Ins come with P2 plug. And although it may be a good enough connection for mics made for home use, these plugs leave much to be desired when it comes to producing music. Besides, as a rule of thumb, the quality of the audio conversion will be far worse than one of even the cheapest interfaces. Ideally, you should use an input designed for your microphone. In other words: a XLR line-in found on soundboards. As a matter of fact, if you use your common computer input, you won't be able to use a condenser microphone, which are much more sensitive to sound detail. This is due to the fact that your common computer mic input, doesn't supply phantom power, needed for a condenser microphone to work. You can use a condenser microphone through USB, though. These kinds of mics have a built-in AD converter and receive phantom power through the USB. This could be a practical, yet temporary, solution. Some models of USB microphones aren't that good in quality, and aren't ideal for music production. Also, you're stuck to only that AD converter. You could end up with an amateur rig.

What is an audio interface for if I only produce electronic music?

Even if you don't record voice or instruments and your work is 100% in-box, a soundboard will get your creative juices flowing. If you're producing electronic music, you will work with Plugins : programs that run in your DAW. You will use effects Plugins, such as delay and reverb. You will also work with virtual instrument Plugins , such as synthesizers.

Normally, you will be using many Plugins all at once. This overload your computer's processor. It can be annoying when the DAW crashes exactly when you have just had and amazing idea, right?  Besides diminishing the latency, using an audio interface ensures that your programs don't freeze up so often, providing a better work-flow. In a further note, some interfaces allow you to use exclusive plugins that run directly inside the interface's DSP, such as Universal Audio's.

Buying your audio interface

Is it time to invest on an audio interface? Here are some buying tips:

Things to look for when buying your audio interface.

  • The Line and Mic inputs and outputs.
  • The type of connection to the computer. (Usb 3.0, Usb 2.0, Thunderbolt, Firewire, etc)
  • The SNR (signal-to-noise ratio) and THD (total harmonic distortion) values.
  • If it has an internal DSP signal processor.
  • If it has good quality pre-amps.

You will find more information on these traits and other on this article about choosing an audio interface.

Mic and Line Outputs and Inputs

As far as the number of inputs go, you should consider how many instruments or voices you intend to record at once. So, if you plan to record an orchestra though individual mic-ing, for instance, you will need many microphone inputs. However, nor regular home studios, two inputs are enough.

  • The interface must have XLRs for mics and P10s for instruments.
  • Don't forget to check if the interface provides Phantom Power for the use of condenser mics.
  • Also check for a pair of P10 outputs for your monitors and a P2 or P10 stereo output for headphone.
  • An RCA output or input could be interesting. It makes it easier when connecting some unusual gear with this kind of connector.
  • Check for MIDI ports: the ones with 5 pins. MIDI (Musical Instrument Digital Interface) is the language that allows you to work with virtual instruments. Nowadays, MIDI data can be transferred in many ways, through USB or bluetooth, but MIDI connectors are extensively used to this day.

The type of connection with the computer

Soundboards come available with USB ports, Firewire or Thunderbolt. Make sure your computer has an adequate connection!

  • Firewire: The Firewire connection is currently being abandoned. Watch out!
  • Thunderbolt: The Thunderbolt connection transfers data at great speeds, but not every computer has this port.
  • USB: As far as USB connections go, it must be 2.0 or higher.

SNR (signal-to-noise ratio) e THD (Total harmonic distortion)

SNR indicates noise and interference levels in the audio signal. The higher the SNR, the better the audio will be. THD tells you the level of distortion. The lower the THD, the higher sound fidelity. (Note: Not always THD is a bad thing. Vintage gear or effects sometimes produce a kind of distortion which is desired.)

DSP sinal processor

Nowadays, high quality soundboards are integrated with DSP (Digital Signal Processing). DSP is a digital signal processor which share the sound processing task with the computer. In other words, a dedicated processor. DSP can be very useful if your computer's processing power is much. Interfaces with DSP sometimes also offer effects such as reverb and compression.

Pre-amp quality

If your recording, it's crucial that you check for the quality of the pre-amps for each input on your soundboard.

Affordable and popular interfaces.

Check out five interfaces with with excellent cost/benefit, ideal for small home studio setups. They all contain:

  • 2 pre-amplified inputs for mic or instrument.
  • Phantom Power.
  • Headphone outputs.
  • USB 2.0 Connections.
  • Active speaker outputs.

Focusrite Scarlett 2i2

  • One of the best-selling soundboards in the world.
  • It's known for its excellent pre-amps and by a great signal-to-noise ratio.

M-Audio M-Track 2x2

  • Excellent price!
  • It only has one XLR port.

Tascam US-366

Has among its key advantages:

  • Optical and coaxial ports,  which allow you to plug a CD player or an effects rack.
  • DSP mixer.
  • Built-in compressor, equalizer and reverb.

PreSonus Studio 26

  • 4 ative speaker outputs.
  • 5-pin MIDI port.

Steinberg UR22

  • Well known for their goos pre-amps.
  • Has a 5-pin MIDI port.
Magroove Magroove