Beginners Guide To Audio Interfaces

In his beginners guide to audio interfaces, Will Bradbury explains how they work and how to choose the right one.

You might be wondering if you really need an audio interface. While you can record music without an audio interface, it's essential that you have one if you want to create high-quality sound.

People sometimes ask what can be used instead of an audio interface – unfortunately there's no real viable alternative unless you're willing to sacrifice sound quality.

However, if you're not quite ready to invest in your own music production hardware, you can book a recording studio in the UK, US or Germany with Pirate. All of Pirate's studios come with professional-grade equipment as standard, including a Focusrite audio interface.

What is an audio interface?

An audio interface is one essential component of any home studio. If you plan to record into your DAW and playback your tracks in high quality, it will be well worth the investment.

Whilst there is some variation in audio interfaces, they all essentially boil down to the same thing – acting as the middle-man between external electronic instruments and microphones, your recording software and your monitors.

How Do Audio Interfaces Make Sound Better?

If you were to try recording-in directly, say with a USB microphone which is running directly through your computer’s soundcard, you’ll soon find that both the volume you are recording in is not loud enough and that your CPU is getting maxed out quickly, potentially leading to your software to crash. This is because these soundcards aren’t designed for high-end audio processing (not everyone with a laptop makes music!), which is why you’ll need an external piece of hardware, your audio interface, dedicated to doing this heavy lifting.

When recording-in with an interface, two things take place:

1. The external signal, or the sound you are recording, is boosted by an in-built pre-amplifier. Microphones output a very ‘low signal’, so a good pre-amp boosts volume without adding much ‘electrical noise’ which also gets picked up, giving you a ‘clean’ recording.
2. The signal also has to be processed by an analogue to digital converter, codifying the signal into a binary code that your computer can read. Good quality convertors are crucial in translating the quality of the sounds between analogue and digital formats.

Conversely, the audio interface also converts the digital signal it receives from your computer back to analogue so that the music can be played back through your headphones or speakers. This outgoing signal is often different to the initial one sent in. Say you have an FX chain on the channel you are recording in. Your DAW will have to process the raw recorded audio through this chain, which would give you a new waveform being sent back out which you’d hear..

Direct Monitoring

Another really useful pure songwriting advantage to using an audio interface is their ability to enable direct monitoring – a feature which adjusts for latency, the delay during which all the processing mentioned above takes place.

"Direct monitoring allows you to listen to the input signal of the interface with near-zero latency. It takes the input signal on the interface and sends it straight to the headphone and line outputs on the device. The signal is still sent to your DAW software allowing the input to be recorded at the same time)" – Focusrite

Essentially what it allows is for you to record in ‘real time’ and particularly useful if you are working on a song with multiple tracks or needing to add vocals to some backing tracks.

How To Choose The Right Audio Interface

Once you start looking, the range of audio interfaces the market offers is seemingly endless.

There are two questions you need to ask yourself in order to choose the right audio interface:

1. What connections do I need?
2. How many inputs/outputs do I want?

The first addresses whether you will be able to connect your interface to your computer, so is pretty essential to get right. Thankfully, if you’re looking at more entry-level models, overwhelmingly you’ll find that manufacturers use USB or Thunderbolt cables, which should be compatible with almost any modern computer or laptop.

How many inputs you’ll need really depends on how many instruments you plan to be recording at the same time. Inputs normally take either xlr cables (balanced) and or line/instrument jacks (unbalanced) and many interfaces often allow both these connections. Outputs on the other hand are most commonly TRS jacks. If you’re using a midi controller – you may also want to look at getting one with a midi I/O. But generally this isn't necessary as your controller will be plugged in via your computer’s USB port.

At its simplest, a ‘2i’ (two inputs) will allow you to record one instrument at a time in stereo, such as a drum machine, utilising one input for the left channel, and the other for the right. This needs to be configured and panned correctly in your DAW. You could also record a DJ mix through an interface using L/R line jacks.

Microphones on the other hand, will only require 1 input at a time, being a mono- recording. So if you’re a singer songwriter primarily making music with an acoustic guitar, an interface with two inputs should allow you to do this if you have two microphones. If you want to play in a piano later, you can do so using direct monitoring after having laid down the backbone of a track – then you might want to re-record a crisper version of the vocal afterwards.

TIP! Look out for the Phantom Power feature if you plan to be recording with a condenser microphone – these have high clarity and sensitivity and are commonly used for vocals, amps and acoustic instruments. It is often labeled as ‘48v’ on the interface:

"This is a must have feature if you are planning on doing high quality voice over work or recording a band" – Roland

Do I Need A Mixer If I Have An Audio Interface?

When you're new to music production, it's important not to buy equipment you don't need. If you find yourself choosing between an audio interface vs a mixer for your home studio, I'd definitely advise going for the first option. You can record with an audio interface and use a DAW instead of a mixer – the DAW will give you an endless number of channels and act as a digital mixer, working just as well as the hardware alternative.

When To Upgrade Your Audio Interface

If you’re finding 2 inputs too limiting – you may want to look at getting a 4-input, to jam on a drum machine and a synth and guitar for example. However, these cost considerably more. If you're budget is restricting, a good workaround is to record one musical element at a time.

Recording live drums is when things start to get complicated. In professional studios, every aspect of the kit is miked up, sometimes with multiple mics on the same bit of it! If you're looking to do this in your home studio, you're definitely going to need a top-level solution.

Buying an interface with more inputs won’t necessarily improve the quality of the audio interface itself, nor your songwriting process. When starting out, I’d really recommend looking at recording something with fewer inputs for a home set-up - limitations can be helpful!

By far the most entry level model in my experience is the Focusrite Scarlett 2i2. If you have a bit more cash to splash, you may want to look at the Apollo Twin MKII, which could be considered more of a ‘professional’ standard and comes with hybrid UAD-2 plugin software.