Which Audio Interface should I get? Let's dive right in!
The first things that you need to figure out that will significantly narrow down your options are:
How many inputs/instruments/microphones do you record at once on a regular basis?
What computer do you have currently, or that you plan on using to record?
Interfaces have a certain number or channels of inputs and outputs. So figuring out what you need to connect is paramount. E.g. if you are a singer/songwriter and only plan on using one mic for vocals and one electric guitar, you could get a 2ch interface. If you are a drummer, or plan on recording an ensemble, you will need more inputs.
Just a quick overview of the types of inputs that typically come with interfaces:
XLR - this is used to plug in a microphone.
Hi-Z aka Instrument Jack - used to plug in a guitar or bass.
Line Input - used to plug a keyboard, synth, amp modeler, or an external mic preamp.
Combi Jack - a combination of an XLR and Line input in one.
Similarly, outputs are a really important consideration and can be confusing for people new to recording. Outputs are used to connect external equipment like speakers, headphones, and outboard gear. It makes sense to check how many speakers and headphones you plan on connecting directly to the interface. This will also help to narrow down your choices. Inputs and Outputs are generally referred to as I/O.
Next, what computer are you planning on using? This significantly reduces the number of options. Just a quick rundown on this topic:
MacBook Pro and MacBook
These days, MacBooks have Thunderbolt 3 ports, so you should go for an interface that utilizes TB3. Just to clear up the confusion TB3 and USB-C are the same types of connectors, but TB3 is proprietary to Apple and allows you to power devices, in addition to transferring data. A USB-C device will work perfectly plugged into a TB3 port. But a TB3 device will not work with a USB-C port. All products will designate whether or not it is TB3 or USB-C, so it is worth double checking to avoid any complications.
Older Macs may have a Thunderbolt 2 port, which is an entirely different connector. If you have computer with TB2 you will need an interface that also has TB2. However you can have a newer computer with TB3 and still connect a TB2 interface using an Apple dongle adapter. These can get pricey and are easy to lose.
Mac Desktops (iMac, Mac mini, etc.)
Usually have various connectors so check the back of your computer to figure out what you have available. This would generally be USB 3.0, Thunderbolt 3 and Thunderbolt 2 for older Macs, which would all work perfectly well for audio recording.
Windows Computers
Should have USB-C, USB 2.0 and USB 3.0 ports available and all work perfectly well.
Switching between Windows and Mac
Would likely need to use a USB interface!
Quick note on a common misconception - you absolutely can record high quality audio with extremely low latency on any of these connectors. USB is not necessarily inferior, and tech companies will throw a lot of jargon at you to persuade you to buy the latest and greatest.
Quick note on USB Hubs, Thunderbolt Docks, and dongle hubs - these can be great if you have a lot of things connected to your computer and not enough ports. This is a very common issue with Apple products lately. Unfortunately, good Thunderbolt Hubs can be very expensive. If you need to use a hub, definitely get a powered one. And I would recommend connecting your interface directly to the computer and use the hub for other peripherals. Kensington, OWC, and CalDigit make the best hubs out there for Mac.
Finally, I will discuss a few quick picks for Audio Interfaces I have enjoyed using on different systems!
Mac Laptops and Portable Mac Setups using Thunderbolt
Universal Audio Arrow and Apollo interfaces are wonderful.
Portable Mac or Windows setups using USB - budget friendly Interfaces
I really like the SSL interface, and Focusrite, which are super budget friendly and portable. Universal Audio also just released the Volt series which would work great.
Higher End - Less Portable Mac Thunderbolt Setups
Universal Audio Apollos are great.
High End - Rackmount Windows USB Interfaces
All about RME!
One last note about technical jargon and other protocols that may come up in your gear shopping experience:
There is a ton of marketing jargon used by music tech companies to indicate how high quality sounding their products are. Unless you are an extremely discerning professional, which wouldn't make any sense because you wouldn't be reading this, most of that is not going to make much of an audible difference to you so don't split hairs over tech specs. I know huge songs that have been recorded on a $200-$300 interface.
I would be wary of companies trying to market bundled software to you. Unfortunately this is the case with Universal Audio. They have established themselves as a reputable plugin company in the industry, but you do not need to buy add-ons to record.
A few types of interfaces that you might see that I did not cover: Ethernet (more for specialized high end systems), Firewire (very outdated at this point), and PCI (which is a chip that has to be installed in your computer and is for high end systems). So these are outside the scope of this article.
Daisy Chaining interfaces - you definitely can connect multiple interfaces to your computer and setup an aggregate audio device to record both of them simultaneously. However, I would not recommend doing this unless you are an advanced user, as it can be really confusing to setup and get working.
ADAT is a type of connection that will allow you to expand your I/O by connecting another ADAT compatible device. This is a key feature of some of the UA Apollo Interfaces because it lets you daisy chain them together and expand your I/O. You would only need this if you plan on adding more inputs in the future.
Mic Preamps that are built into interfaces are generally intended to be clear sounding and will be bashed by music recording enthusiasts as sounding 'sterile' or 'cold'. Mic Preamps are typically included in an interface for your convenience. Discerning recording engineers will almost always use external mic preamps.
Order of importance when spending money on gear. Assuming you have a functioning computer, a DAW, and a decent audio interface, I would recommend spending money in this exact order. Instruments > Acoustic Treatment > Microphones > Studio Monitors/Headphones > Mic Preamps > VST Plugins. So in other words, spending a lot of money on mics and speakers will not do you much good if you haven't acoustically treated your room properly, you see what I mean?
Thanks so much for reading, I really hope this cleared things up and is helpful to you. Let me know!