What is an audio interface?

Simply put, an audio interface is a physical device that allows you to get sound in and out of your computer.

One of the first things you’ve probably been told to invest in when starting out as a music producer is an audio interface. However, to actually know which interface to get, you’ll need to understand what makes up an audio interface, and why you would need one.

Who needs an audio interface?

Every mobile phone, tablet, and computer comes with a built-in audio interface. All of them have a mic that captures sound and speakers or an audio output (such as a headphone jack) that emits sound. So you may ask, “Why would I need an audio interface if my computer already comes with one?” Well, the answer is dependent on how you create music.

The truth is, if you aren’t going to be recording anything and you’re just using your headphones, you can possibly hold off on getting an interface for now. But if you want to record something with a microphone or connect your computer to external speakers, you should probably invest in an audio interface.

What makes up an audio interface?

Audio interfaces come in many different configurations and specifications, but all of them are just variants of the following key components:

Inputs and outputs

Many audio interface manufacturers make several variants of the same type of audio interface. More often than not, the variants are based on the number of inputs and outputs the audio interface has. More inputs allow you to record more tracks simultaneously, while more outputs allow you to send your audio to multiple audio destinations simultaneously.

If you’re a singer-songwriter or bedroom producer who’s interested in recording no more than two microphones at any given time and you have just one pair of speakers, you would probably be good with just a two-input / two-output audio interface.

Note that some audio interfaces may have options for taking in digital optical inputs to expand your audio interface input and output options – more on this in a later blog post.

Microphone preamps

Related to inputs on audio interfaces are what we call microphone preamps. These are the circuits inside the audio interface that boost the signal of the microphone you have connected to your preamp. Some audio interfaces are very expensive because they have high-quality microphone preamps that boost a mic signal in a clean and pure fashion, without any noise. However, a lot of affordable audio interfaces in the market these days have pretty solid microphone preamps that don’t burn a hole in your pocket, thanks to the wonders of technology.

Audio converters

You’ll probably see the term “supported sample rates” on most audio interfaces, along with numbers such as 44.1 kHz, 88.2 kHz, 96 kHz, 192 kHz, etc. This is related to how the audio interface can handle converting your captured audio (analog audio) into digital signals in a way that allows your computer to “read” them. Naturally, the higher the sample rate, the better the audio quality and the bigger the file size. Audio professionals pay huge sums of money for interfaces with pristine state-of-the-art converters. After all, you can have the best microphone, the best microphone preamp in the world, and the best vocalist, but if your audio converters that turn your recording into a digital signal are low quality, then your resulting audio will be of poor quality.

Audio converters do not exist only on the ‘front end’ when capturing audio – they also exist on the ‘back end’ when digital audio from your computer needs to be converted back to an analog signal, so that your speakers can play it back. Generally, audio interfaces with high-quality audio converters will cost more money.

Monitoring section

Every audio interface has what we call a monitoring section. This is usually comprised of a volume knob, a cue output (or headphone jack), and maybe a toggle to switch between different pairs of speaker outputs. Usually, the more monitoring options an interface has, the more costly the interface is going to be.

Types of audio interfaces

When we mention interface types, we mean the way the audio interface connects with your computer. These days, most interfaces come with USB 3 connectors or USB-C connectors. For most use cases, a standard USB 3 connector should be good enough, but if you need much lower latency (this only matters when you’re recording multiple inputs simultaneously), then go for a connector with a higher bandwidth such as the Thunderbolt connector.

Which interface should you buy?

Audio interfaces range in price points from under one hundred dollars to a couple of thousand dollars. Realistically, if you’re starting out, it’s wise to grab an audio interface that’s not too expensive, but also gives you the option to expand your setup later on.

Focusrite’s Scarlett interfaces really deliver bang for your buck. They’re built with high-quality converters and preamps, while being at a reasonable price. What’s even better is that we have partnered with Focusrite to offer a promo code for three months of free Splice Sounds to anyone who buys a Scarlett interface.

If you have any questions about audio interfaces, or if you’d like more blog posts around picking the right audio interface, let us know in the comments below.

July 2, 2019

Reuben Raman Product Marketing Manager at Splice