Which Audio Interface Do I Need?

Updated 13/9/16
Focusrite Scarlett 18i8 Second Generation (2nd Gen) USB Audio Interface

Deciding which audio interface to buy can be a bit bewildering – here’s a guide to help you find what you need

It’s fair to see that, within these pages, I regularly enthuse about the incredible power and functionality offered by even modest home studios these days. The problem with having easy access to such power is that the market is rammed with devices of every kind for every scenario.

The audio interface market is one such area. This can make deciding which audio interface you need a tricky prospect, particularly if you’re a beginner.

This mini guide aims to make finding the interface for you more straightforward.

USB, Firewire, Thunderbolt?

This is the means by which the audio interface connects to your computer, and transfers audio data back and forth from the device. To use an interface of a particular kind, you will need the correct connection on your host computer (i.e. if you want to connect a Firewire interface, you’ll need a Firewire connection etc.).

There are some differences between the three protocols- here’s what you need to know.


Which Audio Interface Do I Need? - USB

Far and away the most popular audio interface type, USB stands for Universal Serial Bus. It was devised to be a universal standard for connecting peripherals, and it’s done a fairly good job. FUSB doesn’t sound quite as good as USB, though…

You’ll find USB connections on just about every computer made in the last 10 years, making a USB interface a fairly safe bet.

Initially, USB 1.0 interfaces had a pretty slow data transfer rate. This meant that they could only handle two channels of input and two channels of output at a maximum rate of 48kHz before they ran out of bandwidth. So, recording large numbers of tracks simultaneously was out of the question.

Focusrite Scarlett 18i20 Second Generation (2nd Gen) USB Audio Interface

Thankfully, the protocol was updated to USB 2.0, which was far faster. Nowadays, there are countless multi-input/ output USB interfaces. To use a USB 2.0 interface, you need a USB 2.0 socket, but if your computer was made in the last 5-years, the chances are, all of its USB sockets will be USB 2.0.

USB devices are often powered over the USB bus.


Which Audio Interface Do I Need? - Firewire Symbol

Firewire (sometimes labelled as IE1394) was originally developed by Apple as a network protocol. However, the video and audio community soon hi-jacked it to their own ends.

With fast data transfer (akin to USB 2.0), Firewire devices were perfect for handling multiple channels of audio data. As a result, up until fairly recently, audio interfaces with high I/O counts were generally Firewire.

As Firewire is a network protocol, it also has the advantage of being able to chain devices (you’ll often find an extra Firewire socket on the back of Firewire interfaces).

Which Audio Interface Do I Need? - Focusrite Saffire Pro 14

There are two types of Firewire connection: 6-pin (which will carry power to a device) and 4-pin (which won’t). There is also a faster Firewire standard: Firewire 800. There are no interfaces that exploit this faster standard, though modern Macs tend to come with an 800 socket. Connecting a standard Firewire 400 to this is a simple matter of buying a Firewire 400 to Firewire 800 cable, however.

Firewire sockets are becoming less and less common on computers, though expansion cards to add them are inexpensive (plus Thunderbolt can used as a Firewire connection).


Which Audio Interface Do I Need? - Thunderbolt Logo

Thunderbolt is the latest device connection protocol, and as the name might suggest, it’s very fast indeed. To put it into numbers, Thunderbolt is capable of a transfer rate of 10Gbps, whilst USB 2.0 is rated at 480Mbps.

It’s designed so that you can effectively run all of you devices (monitor, hard drives, interfaces…) from a single connection. As such, it can be converted to multiple Firewire or USB ports.

However, there are currently very few Thunderbolt audio interfaces available. In the next few years, this is likely to change.


Whilst most interfaces are both Mac and PC compatible (and many even iOS compatible), you will still need to check that the interface you have chosen supports the operating system that your computer is currently running.

Are you running Windows Vista, v7 or 8? Is a 32-bit version or 64-bit? If you use Mac, are you running OSX 10.5, 10.6 or 10.7? If the drivers don’t support it, then it won’t work.

Inputs and Outputs

Which Audio Interface Do I Need? - Scarlett-18i20

What are you aiming to record? Just your vocals whilst you play guitar? Or a full band with a close-mic’d drum kit? This will dictate the number of inputs you will need. The number of inputs will dictate how many simultaneous separated tracks you can record.

If you will only ever need a couple of input channels at any one time (like a singer-guitarist), then a simple, 2-input, 2-output interface will be sufficient. Check out the M-Audio M-Track 2X2M C-Series Audio InterfaceFocusrite Scarlett 2i2 or 2i4 for some excellent examples of this type of compact audio interface.

Which Audio Interface Do I Need? - Octa-Capture interface

If you are aiming to record many tracks simultaneously, such as a recording of a full band, or a multiple microphone set-up on a drum kit, then you will need bigger compliment of inputs. The Scarlett 18i20 2nd generation and Roland Studio Capture are both excellent examples of this.

Audio interfaces with many outputs are designed for those who wish to send individual audio channels out to other external equipment. For example, you may wish to mix on a real mixing desk (in which case you will need an output for every channel you wish to use on the desk), or, you may wish to use external effects.

Most audio interfaces will come with a mixture of jack and XLR inputs, which can usually be switched to some degree between line, instrument and microphone level inputs. Again, think about what you are likely to need, but bear in mind that you can add a few more pre-amps to convert line inputs to mic inputs if needed via external preamp units.

If you are aiming to use a condenser mic, always make sure that the audio interface you buy is capable of supplying phantom power to the microphone.

Take some advice

Which Audio Interface Do I Need? - Roland Studio Capture

It’s always asking for some advice at your local Dawsons store, or via our customer service team. Whilst most people get to see a few of the audio interfaces out there, the guys in our team get to see a huge chunk of what is available. As a result, they have a very clear picture of what is likely to meet your needs.

For a full range of audio interfaces, see our online store here. Alternatively, call our stores or customer service team (01925 582420) for help and advice.