If you’re building a home studio or portable recording outfit, The audio interface is one of the most integral parts to your whole setup. While you may record a range of instruments and switch in new microphones, your audio interface is that constant piece of kit that you’re going to be using time and time again. It is the nerve centre for all of your audio going in and out, so it’s important you get the right one to suit your needs.
These days, you can record what you like, wherever you like and as a result the recording market has exploded with a vast range of recording interfaces to suit a wide range of applications. This beginner’s guide is here to remove the guesswork and help you find the best audio interface for your dream recording setup.
Choosing your audio interface
In order to find the best I/O interface to suit your needs, you’ll need to consider a few things that'll quickly narrow your choices to a few options:
Your Recording Environment
The First thing to establish when choosing an I/O interface is the environment you are planning to record in. Are you hoping to set up an established project studio/producer setup in the spare room? Or maybe you want a portable studio that you can bring to any venue powered by a laptop. If you need something truly portable, you might be happy with a simple all in one device that’s discrete so that you can record at the press of a few buttons?
I/O Interface Options
- Desktop - the desktop audio interface is the perfect choice for a small project studio. Most desktop interfaces have a good range of inputs and the essential features you’ll need to record without going overboard with inputs.
- Rackmount - rackmount interfaces are designed to fit into an audio rack so that you can combine lots of outboard gear without taking up too much space. The larger format provides room for more inputs and preamps.
- Mobile - any desktop interfaces these days are “class compliant” so that you can connect them to your iOS device with an Apple camera connector. However there are some devices that have been specifically designed for mobile use. Most of these focus on a single mono/stereo input made intuitive and easy to use. These include guitar interfaces, stereo mics for recording gigs, and discrete lapel mics for recording speech. There's an interface for all your mobile needs.
- Handheld - if you prefer to keep your recording work completely all in one and separate from the rest of your mobile devices, you can also choose a handheld interface. These light and portable devices usually feature a high quality stereo microphone that is great for on-location recordings, sound design and capturing a gig. Some models also feature other inputs so you can connect other close up microphones for a more detailed recording. You won't have as much editing power on location, but you can easily transfer the files to a PC.
A key decision on what input/output interface works for you may be out of your hands unless you’re planning to buy a new computer too. You'll need an interface that is compatible with your machine. Interfaces are made with a variety of connections listed below, so make sure you can plug it in!
- USB - the standard connection that almost all computers have. Most modern wired gadgets connect to your computer this way, including phones, cameras and tablets. USB2 has been out for a long time and is one of the slowest connections of the bunch. However, new computers and the latest interfaces have USB3 Connections that offer much faster data transfer.
- Firewire - this was created by Apple as a faster alternative to USB so you’ll find it on older Macs. However Firewire 800 has been replaced and outdated by Thunderbolt and USB3. Audio interfaces clearly listed as Firewire connectivity will only work with Apple products. Do not go with one of these if you have anything other than a Mac.
- Thunderbolt - also created by Apple, Thunderbolt is the current fastest connection to your audio interface. There are now a number of Thunderbolt Interfaces out on the market, which offer ultra-low latency and unparalleled performance. All the latest Macs come equipped with Thunderbolt inputs, but if you’ve got a Windows PC you might need to get an input specifically installed.
- PCI Express - this is an internal card-based computer connection platform that’s primarily found in desktop computers. Since these cards are plugged directly into the PC motherboard, they require an available PCIe slot for installation, which some computers may lack.The PCIe connection provides high data bandwidth and low latency, allowing audio interfaces that use it the ability to handle many simultaneous inputs and outputs.
- Ethernet - super high-end. It's not needed for home use as the quality doesn't justify the cost. But it's the best option for professional studios and broadcast facilities that have tens of thousands to spend on recording equipment.
Inputs and outputs
One of the biggest choices you’re going to have to make when buying an audio interface is what inputs, outputs and features you’ll need. Sound can be captured in a variety of different ways so it’s important to work out the quantity and type of inputs are appropriate.
For example, if you’re a singer-songwriter you may only need a small interface with a couple of inputs for overdubbing. However, if you’re looking to record a 5 piece band together, you’ll need a mixture of inputs; including a number of microphone inputs for the drums alone. Listed below are the types of inputs available and what they're used for.
- Jack - inputs used for guitars, bass, keyboards, synths and external gear. Stereo instruments like Keyboards will need 2 jack inputs for the right and left channels. Outputs are used for connection to monitor speakers and any analogue effects and other gear that you want to feed through an effects channel (bus).
- XLR - balanced Microphone inputs. XLR mic inputs are combined with a microphone preamp that boosts the signal to a usable level. Each preamp comes with a gain knob so you can set the level of boost on the signal.
- Combo Jack XLR Inputs - often, audio interfaces will have their most accessible inputs as a combination of jack and XLR so that you have the option of plugging in easily without having to reach to the back of the unit.
- 3.5mm Jack - this allows you to hear what you're recording through headphones or speakers. If you want an accurate representation of the sound you're producing, get some good full range FRFR monitors.
- S/PDIF (Sony/Philips Digital Interface) - this is the main input/output for any digital sources. Whether it’s a digital effects module, a sound box or a keyboard arranger, the digital input saves you from any noise that might come into the signal through an analogue input. S/PDIF comes in 2 different formats; Coaxial or Optical. Make sure that any devices plugged in have the right connection!
- MIDI - used to plug in peripherals that can control the software in your computer. For example, a keyboard can be hooked up so to play software instruments hosted on the computer. Some modern dedicated controller peripherals have USB connections that plug directly into your computer, however with most keyboards, MIDI will be your only option.
- ADAT - an optical connection that allows you to transfer digital audio between different equipment. It can transfer up to 8 channels at 48 kHz/24bit.
"Your signal chain is only as strong as your weakest link!"
There are a number of key elements in an audio interface that will determine the overall quality of your system.
The journey from microphone to computer (your ‘signal chain’), is only as strong as your weakest link. You may have the most expensive and legendary microphone that captures sound in incredible detail , only for it to run through a bad cable or into a poor interface. All that gorgeous detail can be lost or drowned out by background noise.
When recording with microphones, the preamp is the first element in your interface that will affect your sound. A microphone naturally captures sound at a relatively low volume level, so it’s the job of the preamp to boost it back up to its original level. Most I/O interfaces have in-built preamps so you can plug in and record straight away. However, external preamps contain more features and provide better quality in the vast majority of cases.
A decent pre-amp will boost the sound with superb clarity, whereas a lower quality preamp will also bring in background noise and unwanted imperfections. Although some imperfections can be good. Top preamps aren’t just clear and crisp. They bring unique colouring to a recording. Whether it’s a bit of analogue warmth or what producers call “air”, the best mic preamps have their own signature sound and are highly sought after.
An interface may also provide phantom power. This is needed for condenser microphones that won't work without an external XLR compatible power supply. Most I/O interfaces have a switch to turn it on and off. It'll run through the standard XLR chain the microphone uses to deliver the sound.
The converters in your interface are another key element to the quality of your recordings. There are two different types:
- Analogue to Digital Converters (A/D) - this type of converter takes the analogue waveform coming from your preamp and converts it into a digital signal that the computer will understand and feed into your recording programme (DAW). It’s a key element of your recording path.
- Digital to analogue Converters (D/A) - these do the opposite to A/D converters. They take the Digital signal and convert it back to an analogue waveform that can be sent to your monitor speakers. This conversion doesn’t directly affect your recordings but it does affect playback, i.e. what you hear.
The converters on most good quality audio interfaces are capable of excellent sound. The main factors to take into account are the Sample rate and bit depth. In a nutshell, sample rate can be described as the amount of sound detail, and bit depth as the representation of the dynamic range (how many different volume levels between your quietest sound and loudest sound).
Sample rates on interfaces can reach up to 192khz and to a bit depth of 24-bit, however it’s worth noting that standard CD quality is much lower at 44.1khz/16Bit. Part of the reason they're now outdated is because they don't provide an accurate representation of sound. When buying an I/O interface, it's worth thinking about what you are going to do with your music once created. Does it need to be the pinnacle of quality?
Today, a good benchmark for “high resolution” audio is considered at 96kHz/24bit upwards. Better circuitry and more accurate clocking leads to a more precise, focused sound. The benefits of high end conversion are subtle and need high-end speakers to fully appreciate.
Latency and software
Latency used to be a bigger issue than it is today, but still worth recognising. If you have ever recorded before, you may have noticed some lag between playing something and hearing it through your speakers/headphones, and the recording also appearing on your DAW. There is a small delay of a few milliseconds as it passes through the audio interface.
This will never be completely eradicated, but USB3 and Thunderbolt's processing is so good, it's not really noticeable. The only downside is that these interfaces are pricier than USB and Firewire. But it makes such a difference to temper levels, it's probably worth it.
Most audio interfaces will work with all types of DAW software. If you're buying an interface for the first time, they will usually provide a DAW download to work with it anyway. Just in case, check the compatibility between the two. It's usually safer to pick a brand and stick with it, as you will also learn how to use the software as you go. Although they all look similar, recognising functionalities will save you a lot of time working out unfamiliar workstations.
There are a lot of companies making audio interfaces, so it can be a bit difficult to work out who makes the best. Here are a few of the biggest names you should know and will probably see as you research what one you’re after.
- Focusrite – one of the most popular brands at an entry level price range. Pretty much everyone has used the Scarlett USB interface at some point. Cheap, does a clean job, reliable and looks sleek on your desk. But that’s not all Focusrite do. They have a mid-priced Clarett range with MIDI connections and newer Pro models that comfortably challenge the very best in the world.
- Universal Audio - if you’re looking to splash some cash UA are worth a look. Their entry level interface comes in over £400. However, these guys offer great plug-ins and great preamps. Not much comes close to their Apollo series of rackmount interfaces. Every type of I/O you could want, top A/D D/A conversion and Thunderbolt connection.
- Native Instruments – have a higher reputation for DJ controllers, plug-ins and the Komplete production suite, but make one interface that’s all-encompassing on a budget. Also named the Komplete, this desktop box has two mic inputs, MIDI compatibility and four analogue outputs. The biggest draw the included production package and the excellent and essential Cubase DAW.
- M-audio – a company focused on making beginner interfaces. The M-Track series comes with the Ableton Live DAW and the AIR Creative Collection FX, a popular plug-in package most known for its use on Pro Tools. At 24bit/192kHz you’ll have great recording quality at a cheap price.
- PreSonus – one of Focusrite’s biggest rivals. They also offer a very cheap entry level point called the AudioBox that benefits from its simplicity. Naturally, as you move up the range they offer loads more I/O’s, talkback features, Class A preamps and the PreSonus Studio One DAW.
In an ideal world, we would all love to get the biggest and best audio interface out there for our studio. Unfortunately, high-end recording gear can easily run into the thousands, and won't bring you the leaps in quality you might expect.
Generally, within the various price bands, the more you spend the higher the quality of interface. However, there is a delicate balance between better sound and number of inputs.
That's why it’s important to consider how many inputs you’re realistically going to need, because if you’re a solo musician who records instruments one at a time, avoid buying an audio interface with loads of inputs and instead invest in a good preamp or converter.
Most interfaces allow you to expand the number of inputs anyway, so your recording setup can grow when you’re ready.
The best audio interface for you is one that has all the functionality you need within your budget. Choosing the right interface for you may seem daunting at first, but by carefully considering your requirements, you can very quickly narrow down your choices.