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The humble USB audio interface revolutionized music production when it was first introduced in the market. Instead of expensive mixers, this simple piece of equipment made it possible for anyone to hook up microphones, guitars, and gear to their computers. This guide will help you buy the best USB audio interface for your home studio.
If you're producing music, your biggest enemy is that three syllable word: latency.
Latency is the time lag between sending and receiving a signal. The higher this number, the bigger the lag between pressing a key and hearing it play on your computer.
Your latency is affected by a lot of things, but the biggest culprit is always the same: a poor quality soundcard. Built-in soundcards have come a long way from the early days of computing, but they still lack the speed and power needed for music production. Worse, if you're operating on a laptop or Mac, it's not always possible to pop open the cabinet and install a brand new soundcard in the PCI port.
This is where USB audio interfaces come in handy. An “audio interface” is essentially a fancier name for an external soundcard. This soundcard connects to the computer via a USB port and brings the low-latency and power you need to produce music.
As far as music production gear goes, an audio interface is an absolute must. As I've often advised in these pages, the audio interface should be the third item on your to-buy list (after a DAW and studio headphones). A quality interface will give you that instant playback you need to play and produce music. You can make music without it, but it won't have nearly the same spontaneity and responsiveness.
And USB, being a universally supported and easy to use format, is ideal for audio interfaces.
So in this guide, I'll show you what are the best USB audio interfaces on the market right now. Although the focus is mostly on bedroom producers, I'll also cover mid-range and pro quality picks for the best USB audio interface. And I'll follow it up with a detailed buying guide to help you make better decisions.
If you're looking specifically for Ableton-friendly USB audio interfaces, read this guide instead.[/su_column] [/su_row]
About your reviewer
Ryan Harrell is the founder of MIDINation and an experienced producer/DJ. His first experience with electronic music production dates back to Cubase 3.0 in the summer of 1997, and he's been a fan ever since. He prefers Ableton as his primary DAW these days, though he is still partial to Cubase and Pro Tools. He lives in San Diego and freelances as a producer and part-time DJ.
The 6 Best USB Audio Interfaces: In-Depth Analysis
A USB audio interface is an essential part of any studio setup. It doesn't matter whether you're starting out with just a DAW or already have a full-fledged home studio setup, the interface will be one of the most important elements of your studio.
Having said that, no two home studios are the same, nor should they use the same kind of setups. A solo producer who needs to plug in a single microphone has very different requirements from a producer looking to record an entire band in real time. Everything from the number of inputs to the DAW compatibility will factor in your decision.
To ease your doubts and answer your questions, we'll share a detailed USB audio interface buying guide in the next section.
For now, let's look at our top picks for the best USB audio interface you can buy in 2020:
Best Overall: Focusrite Scarlett 2i2
- Two instrument inputs
- Two Scarlett mic preamps with 48V phantom power
- Supports up to 192kHz/24-bit sample rates
- Low latency (under 13ms)
- Strong usability with a single giant volume knob
- Comes with plenty of freebies, including Addictive Keys
Pop into any home studio and 7 times out of 10 you'll find a little red box sitting next to the computer.
Focusrite absolutely dominates the audio interface market for home studios. And for good reason. Their audio interfaces are easy to use, perform well, and are priced well within the range of most home users.
The Focusrite Scarlett 2i2 is arguably the best among Focusrite's budget offerings. Boasting two MIDI inputs and two mic preamps, this audio interface has everything you need to start recording at home. Plug in two microphones or two MIDI instruments and you're ready to go.
The mic preamps offer 48V of phantom power in case you're using a condenser mic that needs it. the big volume button also makes it easier to control the volume without fiddling with software volume sliders/buttons.
This interface supports sample rates up to 192kHz/24-bit and has an extremely low latency (input latency is below 7ms on my computer).
If you think that two instrument inputs are overkill, you can also opt for the cheaper Focusrite Scarlett Solo. This option ditches the dual inputs for one MIDI-in and one line input. The latter is particularly useful if you want to record, say, an electric guitar along with a microphone.
Installation and setup is easy as well. Plug in the unit and Windows 10 will automatically recognize it. Else, you can easily download the drivers from Focusrite's website. You also get a few goodies, including XLN Audio's Addictive Keys, Ableton Live Lite, and 2GB of Loopmasters' libraries.
On the whole, a great pick for any bedroom producer. Affordable, well-built, and easy to use with low latency and quality audio.
- Affordably priced
- Supports higher sample rates than competitors
- Easy to use; durable build-quality
- No RCA output
- Some driver issues reported on older Windows versions
Best for Beginners: Behringer UM2 Audio Interface
- 1 XLR input
- 1 line input
- 48V of phantom power
- XENYX mic preamps
- Small form factor, low weight
- Large dials for easier controls
On an absolute budget and need to start recording audio?
Then look no further than the Behringer UM2 audio interface.
As one of the cheapest audio interfaces around, the Behringer UM2 doesn't offer a whole lot. You get one mic input and one line input. You can feed it 48V of phantom power, but that's about it.
What you do get, however, is an absurdly low price. This thing costs less than a movie date night – with change left over for popcorn. For people on a budget, this alone is a serious reason to buy the UM2 interface.
Another plus is the small size – the UM2 weighs next to nothing and is tiny enough to fit on the most cramped desktops (as a bedroom producer, I know how crowded desks can get).
As a downside, you are limited to 48kHz sampling rates. This is decent enough for most producers, but if you want to bump it up to higher quality, you're out of options.
Another negative is the preamp. While Behringer's higher priced variants (such as the U-Phoria UMC202HD) gets MIDAS preamps, the UM2 only gets XENYX preamps.
There are also no freebies like Focusrite's offerings.
Given its price tag, however, I can't really complain. The Behringer UM2 works well for most starting producers and is reliable enough to be dragged to live sessions without risk of breakdown.
The small form factor and ease of use are added bonuses.
- Extremely cheap – costs less than dinner for two
- Two inputs
- Small form factor
- Limited to 48kHz sampling rate
- XENYX preamp isn't as good as MIDAS preamps
- Behringer's UMC202HD is better and priced marginally higher
Best Performance (Solo Musicians): Audient iD4
- 1 x JFET D.I. input
- 1 x mic/line input
- Supports up to 96kHz sample rates
- Volume knob doubles up as a virtual scroll wheel
- 114dB dynamic range works great at high volumes
Running a small studio and need more power and finesse than what Focusrite Scarlett offers?
Then the Audient iD4 is for you.
The iD4 is the smallest of Audient's range of audio interfaces. It is designed specifically for solo musicians looking to record a single instrument at a time. The form factor is tiny, but the build quality is superlative.
In terms of inputs, you get a single mic/line input (using a XLR/jack combo plug). You can divert 48V of phantom power for powered microphones.
In addition, you get a rich JFET D.I. input for plugging in guitars or bass instruments. This input is designed to replicate the warmth of a classic valve amplifier.
The output has mini and quarter-inch TRS ports for connecting headphones or studio monitors.
A standout feature is the ample control options. You can uset he Monitor Mix control to blend input and DAW return signals. You can also use it to control panning. Press the ‘iD' button and the volume encoder turns into a mouse scroll wheel to automate volume on the fly.
The sound quality on the iD4 is excellent, and arguably better than Focusrite Scarlett's series (even though it supports a lower sample rate at 96kHz). There is less noise and a distinctive lack of a hum at high volumes. The wider dynamic range – 114dB – also helps.
I particularly like the JFET D.I. input, which creates a warmer sound than the Focusrite Scarlett.
On the whole, solo musicians who need a dependable audio interface will love this offering from Audient. It doesn't have a whole load of inputs, but the innovative volume control knob, and warmer sound make it worth the price tag.
- Great automation features courtesy of virtual scroll wheel
- Faster and richer sound with a low latency
- JFET D.I. input offers richer sound for guitars/bass
- Big output control button feels great to use
- Some driver compatibility issues with Windows 7/8
Best Performance (Home Studio): Arturia AudioFuse 14 x 14
- 3 x USB ports, 4 x phono ports
- 2 x XLR ports
- Dedicated S/PDIF and ADAT ports
- Supports 2 sets of monitors/speakers
- Supports talkback feature with built-in microphone
- Can add up to two inserts
If you've gone through this site, you would know that I'm a big fan of Arturia's products. Among modern manufacturers, I believe that they're at the top of the pile when it comes to design and functionality. I frequently recommend Arturia KeyStep as a beginner MIDI keyboard even over industry stalwarts like Akai.
Which is why I was particularly excited when I learned that Arturia was making a full-fledged USB audio interface for small studios.
And the Arturia AudioFuse did not disappoint.
This is one of the best USB audio interfaces around if you have a ton of equipment to use and limited desk space. You get more inputs than you can possibly use. And you get enough room to attach external compressors and multiple monitors, all in a form factor barely larger than a couple of cigarette boxes.
Here's a partial list of the inputs on the Arturia AudioFuse 14 x 14:
- 3 x USB ports
- 2 x inserts to connect external compressors/preamps
- MIDI in/out port (needs the included MIDI adapter cable)
- S/PDIF input
- ADAT input
- 4 x Phono/line inputs
- 2 x speaker outputs
- 2 x XLR/balanced 1/4″ inputs
Sure, you can find rack mounted interfaces with more input options, but in terms of sheer versatility, the AudioFuse performs admirably. Plus, it doesn't take up a ton of space – an overlooked feature in home studios.
Alongside the usual ports (XLR/line-in), it also supports “modern” inputs such as USB, ADAT, etc. Plus, you can plug in two separate sets of monitors – a must for any intermediate or advanced level studio.
But it's not just the plentiful input options; the AudioFuse also performs admirably in live settings. The latency is much lower than most beginner-level gear. On my i7 laptop with 8GB of RAM, Ableton clocks in a 2.1ms of latency – good enough for all but the most high-end of studios.
This interface also has 75dB of gain which is more than enough for even the most power hungry of passive microphones.
Best of all, the sound through the AudioFuse is richer, more dynamic, and detailed than any $200 beginner-level gear you'll ever use. It's something you have to hear to believe it.
For a mid-range audio interface, the Arturia AudioFuse offers some of the best bang-for-the-buck performance and features.
- Outstanding sound quality
- Pro studio-level latency
- Tons of connection options
- Tiny footprint and great build quality
- Rack mounted interfaces usually offer more ports
- Some reported issues with the phantom power
- Expensive for most home studios
Best for Mobile: IK Multimedia iRig Pre HD
- 48V of phantom power for passive microphones
- +40dB of mic preamp gain
- Supports up to 24 bit, 96kHz of audio
- Connectivity via Lightning or USB cable
- Hardware switch to control pre/post-device monitoring
- Compatible with most iPhone/iPad/Android apps
Record your music on the go? Use Garageband on your iPad and need a better microphone than the built-in one? Experimenting with some music apps on your iPhone?
Then this is the perfect audio interface for you.
IK Multimedia's iRig fulfills a very specific function: to help you record input from a microphone on a mobile device. While you can certainly hook it up to a PC or Mac, it is primarily meant for use on tablets and smartphones.
The features, consequently, are limited. You get just one mic input and a 1/8″ headphone out. Connectivity is via either a lightning cable (included) or standard USB. There are no giant volume control knobs, multiple inputs, or automation features.
The performance is also not comparable to full-fledged computer USB audio interfaces. You get 48V of phantom power for passive mics, but the preamp is rated only to 40dB of gain. You'll also have to carry around 2 AA batteries to keep the unit powered.
Despite all these negatives, the iRig Pre HD fulfills its purpose wonderfully well. The 40dB of mic gain is more than adequate and is matched by the 96kHz of sampling rate. The unit itself is tiny and easy to carry around. Plus, since its powered by AA batteries, you don't have to worry about keeping it charged.
If you record primarily on a PC or Mac, there are far better options on the market.
But if you intend to record on the go on your tablet or smartphone, this is one of the few viable options on the market.
(Note: you can get the analog version of this unit for less than half the price).
- Lightweight and tiny in size for easy portability
- Decent preamp for recording on the go
- Powered by AA batteries means no recharging hassles
- Underpowered preamp
- Included Lightning cable is flimsy
Best Rackmounted Interface: Focusrite Scarlett 18i20
- 8 x microphone inputs
- 10 x line outputs
- Dedicated S/PDIF, Optical and MIDI in/out ports
- USB 2.0 connectivity
- Latency as low as 2.74ms
- Supports up to 192kHz/24-bit audio
Rackmounted interfaces aren't for everyone. For one, you need an audio rack to use them. And two, the number of inputs/outputs (18 in this model) are plain overkill for most home studios. Unless you're recording multiple instruments at the same time, you'll hardly use more than a handful of inputs.
However, in case you do need over a dozen inputs, the Focusrite Scarlett 18i20 should be your top pick.
The first thing you notice about the Scarlett 18i20 is the sheer number input options. You get two XLR/line inputs up front. Turn the unit around and you'll find six more XLR/line combo inputs at the back. Besides these, you also get MIDI, Optical and S/PDIF in/out ports.
For output, you get 10 balanced line outputs at the back (including a dedicated stereo pair) and two headphone outs at the front.
The front of the unit gets dedicated gain controls for the eight XLR/line combo inputs. These use Scarlett's mic preamps and offer up to +50dB of gain with a 109dB dynamic range.
The 18i20's latency is significantly lower than Scarlett Solo or Scarlett 2i2. I tested latency as low as 3.2ms. Focusrite itself claims latency as low as 2.74ms.
Installation is dead simple as well since Windows, Mac, and even Linux recognizes the device and doesn't need any drivers.
Finally, as with other Focusrite audio interfaces, you get a bunch of freebies, including 2GB of Loopmasters samples, 1x XLN Addictive Keys instrument, 3 Audio Thing plug-ins, etc.
There are better rackmounted interfaces out there, but for intermediate level home studio owners, the Focusrite 18i20 does the job remarkably well.
- Tons of input and output options
- Competitively priced
- Easy to install and use
- Mic preamp could have more gain
- Uses USB 2.0, not 3.0
So that covers our picks for the best USB audio interfaces on the market right now.
That still leaves us with a big question: what exactly should you look for in your audio interface? And based on the answers, which of the above would be the right pick for you?
In the next section, I'll share a detailed buying guide that will help you make sense of these questions.
USB Audio Interfaces Buying Guide
Buying the best USB audio interface can quickly get overwhelming, especially if you're new to music production.
At the same time, this isn't a purchase you can put off too long if you're even remotely serious about making music. Some of the other products we've reviewed – studio monitors, MIDI keyboards, digital pianos – an audio interface is almost as important for music production as your DAW.
In fact, I recommend most beginners to buy one right alongside their DAW.
Given the importance of this piece of equipment, it's important to get your choice right. The wrong interface won't ruin your music, but it can slow you down considerably.
On that note, let's dig into the whats and whys of buying music interfaces.
What is an audio interface (and why do you need one)?
As I noted in an earlier article, the human ear cannot hear digital signals. In fact, a digital signal is nothing but a series of 1s and 0s (i.e. binary numbers).
Human beings can hear analog signals (which look like sound waves). But to record these signals to a computer, you have to first convert them into a digital format.
This conversion process takes place via a sound card.
Virtually every one of you reading this has a sound card built into his/her computer or mobile device. This is what enables you to listen to music (i.e. digital files) and record your own voice (via the in-built microphone).
But if you're looking to make music, these built-in sound cards are simply not enough. They have three crucial problems:
- They don't have enough input or output ports
- They can't record or play music at a high-enough volume or quality
- They are underpowered, which leads to latency issues
If you have a MIDI keyboard, try plugging it into your computer directly. You'll find that there is a noticeable lag between pressing a key and hearing a sound. This completely ruins the playing experience.
Which is why you need an audio interface.
An audio interface is essentially a souped-up, external sound card. There are internal audio interfaces that connect to the computer via PCI ports. But most modern ones use USB and sit outside the computer in an external housing.
The audio interface is essentially the hardware that connects all your devices to your computer. Without it, you can't record sound from a microphone, guitar, or MIDI instrument. Even if you bypass the interface and connect your MIDI instrument to the computer directly via USB, your latency will suffer.
Think of it as the “hub” of your music production.
Like a sound card, an audio interface also performs the critical function of converting analog signals to digital signals, and vice-versa. But it does so faster, better, and with more clarity.
Further, an audio interface has far more input and output options than a built-in sound card. You can connect external microphones, MIDI instruments, guitars, etc. to your computer through it.
Beyond this, most audio interfaces also have built in amplifiers. This boosts the signals and makes for more clear and louder recording and playback.
But perhaps the biggest advantage of an audio interface is the lower latency it offers. Most professional USB audio interfaces will clock in a latency of under 10ms. Studio grade units will go as low as 2.5ms.
At this latency, you get instant playback. Press a button on your keyboard and the DAW will respond immeidately. Record vocals and they will be in sync with the music.
I consider a good audio interface as an absolute must for anyone who isn't just fiddling around.
What kind of input/output options do you need?
At its heart, an audio interface is a hardware interface for connecting your devices (MIDI keyboards, guitars, microphones) to your output tools (headphones, studio monitors).
Consequently, the most important factor in your decision should be the audio interface's input/output options.
Your two biggest considerations are:
1. Number of I/O ports
Audio interfaces are usually sold based on the number of input/output options they offer. For instance, Focusrite sells the follow variants of its Scarlett interface:
- Focusrite Solo (1 x combo XLR input)
- Focusrite 2i2 (2 x combo XLR inputs)
- Focusrite 18i20 (8 x combo XLR inputs)
The underlying chassis for all these interfaces remains mostly the same; the only difference is in number of ports.
Now how many ports you choose will depend on what you want to do with the interface and the kind of music you want to record.
If you’re a singer-songwriter who plays the guitar, for instance, you’ll want at least two inputs:
- 1 x XLR input to connect your microphone
- 1 x line input to connect your electric/electro-acoustic guitar
If you’re an electronic musician who only needs to record his vocals, you’ll want an interface that has a MIDI port instead of a line level input.
The more inputs you have, the higher number of instruments you can record at once. If you’re recording a band, for instance, you’ll want at 4+ inputs. Otherwise you’ll have to record each band member separately.
Most studios have large rackmounted interfaces that can accommodate several instruments simultaneously. While this works in a professional studio setting, you’ll find that it’s plain overkill for most home studios.
At the same time, you also need to consider the kind of output options on offer.
Most interfaces will at least offer connectivity options for 1 x studio monitor and 1 x headphones. As you get to the mid-range of interfaces, you’ll find options to connect two sets of studio monitors simultaneously.
Again, pick the number of options based on your needs. If you use multiple studio monitors (common among professional musicians), pick an interface that can support it.
I recommend that most beginners should start by buying the bare minimum number of ports they need. As you realize your own requirements, you can upgrade to an interface with the right number of ports.
Something like Scarlett Solo or Scarlett 2i2 is perfect for the vast majority of beginners.
2. Type of ports
The other consideration is the type of ports the audio interface supports.
The most common port-type is the “combo” XLR+line input, like this:
This versatile input can accommodate a microphone’s XLR cable, a MIDI instrument, or a line input (like an electric guitar).
In addition to this combo input, audio interfaces also offer the following port-types:
- MIDI in/out for connecting MIDI instruments
- S/PDIF in/out, sometimes used in high-end monitors
- ADAT in/out, sometimes used in high-end gear like digital mic preamps
- RCA, for connecting studio monitors
- Line inputs/outputs, for connecting guitars (input) and monitors (line output)
Some modern USB audio interfaces also offer USB ports for connecting USB instruments/preamps.
What type of ports you choose will again depend on the kind of instruments and output devices you expect to use. If you have a home theater system that uses S/PDIF ports, that should be your top pick. If your monitors use RCA, make it a priority in your interface pick.
As a general rule of thumb, get an audio interface that supports as wide a variety of ports as possible in your budget. You never know what you’ll want to hook-up to your computer in the future.
For most beginners, I recommend getting something with at least two combo XLR ports. This will enable you to connect a mic + guitar or a mic + MIDI keyboard simultaneously. This is why the Scarlett 2i2 is our top choice.
What kind of connectivity option should you choose?
Another factor in your purchase is the interface's connectivity options, i.e. the way you hook it up to the computer.
This seems like a moot point since this article is literally titled “USB audio interfaces”. However, there are a few more connectivity options you should be aware of:
Thunderbolt: Thunderbolt is an interface developed by Intel and Apple together. Thunderbolt 3 uses the same Type-C connector as USB, but offers nearly 8x the speed of USB 3.0.
Thunderbolt is often called the “reference” standard in music production. You'll find a lot of high-end audio interfaces using it as their go-to connectivity option.
The problem is that Thunderbolt is only supported by Mac. Additionally, since it is a reference standard, Thunderbolt audio interfaces tend to be expensive. You'll be hard-pressed to find a decent Thunderbolt interface in the under-$500 range.
FireWire: FireWire is another interface developed by Apple. As such, support was largely limited to Mac initially. Even today, PCs supporting FireWire out of the box are rare.
FireWire offers the same performance as USB but with slightly more consistent data transfer rates. This offers extremely marginal improvements in data recording.
However, FireWire is a dying protocol that has been superseded by Thunderbolt on the Mac. USB 3.0 is also faster than FireWire, which kills any compeititve advantage the protocol had over USB.
Because of this, new FireWire audio interfaces are rarely being manufactured. Anything you can buy today is at least one generation old.
For these reasons, I don't recommend FireWire as the connectivity option for anyone.
USB: USB or Universal Serial Bus is the protocol we're all familiar with. This is the protocol you use to connect your hard disks, phones, cameras, and keyboards to your computer.
USB has a lot of issues ranging from speed (at least until USB 2.0) to data transfer rate consistency, but it is also extremely versatile, cheap, and omnipresent. USB 3.0 has also solved most speed issues and can compete easily with at least Thunderbolt 2 in data transfer rates.
But the biggest benefit of USB is its sheer ubiquity. It's next to impossible to find a modern computer that does not have USB ports. You can take your interface from one computer and one studio to another without worrying about port availability.
This ubiquity also means that you have a huge range of audio interfaces to choose from. From $100 units to $2,000 pro-range gear, there is a USB audio interface to fit virtually every budget and need.
In addition to the above, there are also internal audio interfaces that use the PCIe (PCI Express) protocol. These are installed inside the computer on the PCIe slot.
PCIe audio interfaces connect directly to the motherboard. This reduces latency and offers higher bandwidth. But as a downside, you get fewer I/O ports and you can only use them on compatiable desktops. This limits where and how you can use the audio interface.
Bottomline, for 90% of you reading this, USB should be the go-to connectivity option. If you're on a Mac and have a $500+ budget, consider going for a Thunderbolt interface. Avoid FireWire and PCIe unless they fit your specific requirements.
What about latency?
Latency is the time it takes for a signal to move from an input device to the computer and vice-versa. It is measured in milliseconds (ms).
You have separate input and output latencies. Their combined total gives you your real latency.
Thus, if your input latency is 5ms, it means that it takes 5ms for a signal from a microphone or MIDI keyboard to travel to the computer. If your output latency is 5ms, it takes 5ms to transfer a signal from the computer to your speakers.
In this case, your real latency would be 10ms. That is, it takes 10ms for you to press a key and hear it played back on the computer speakers.
Latency is one, if not the most important reasons for using an audio interface. A high latency will create a noticeable lag in your recording or playback.
Latency is affected by a lot of things – your motherboard, computer processor speed, RAM, connection-type (Thunderbolt is faster than USB), and even the kind of DAW you use. But the biggest influence is your audio interface.
Most modern USB audio interfaces offer sub 15ms latencies. This is good enough for amateur use. As you move up the value ladder to more expensive studio-grade gear, you'll find audio interfaces that offer sub 5ms total latency.
Top of the line studio gear offer latency as low as 2ms. At this point, playback is nearly instantaneous.
As a beginner, strive to get an audio interface with the lowest latency you can afford. But don't hang up too much on it. Any interface in the $100 range and up will have low enough latency to make music production not just feasible, but enjoyable.
Strive for the 3-4ms of latency range only if you're an intermediate or pro-level producer.
What other technical specifications should you consider?
Besides latency, there are a few other things you should consider when buying a USB audio interface:
Sampling rates: If you've read our list above, you might have noticed me mention the “sampling rate” supported by each interface.
Think of this as a measure of the number of times the audio interface takes a digital “picture” of the incoming audio every second. An interface with a rate of 96,000kHz takes 96,000 pictures of the audio every second.
CD standard audio is 44.1kHz. Anything beyond this is extremely high-quality.
Most audio interfaces support at least 48kHz of sampling rate. Anything in the $100+ range usually supports a minimum of 96kHz. Pro-quality gear can go up to 192kHz.
As a general rule, the higher the sampling rate, the better. But don't make this the only consideration when buying. An interface that has the features you need and supports 48kHz is better than one that has limited ports but samples at 192kHz.
Bit depth: You might have seen another number mentioned next to sampling rate – 16-bit, 24-bit, etc.
This number is called the “bit depth”.
Bit depth essentially tells you the total audio range (in decibels) supported by the audio interface. An easy way to calculate this is to assume that 1 bit = 6dB of range.
Thus, a bit depth of 16 bits means that the interfaces supports a 16×6 = 96dB of range. This means that audio that falls outside a 96dB range, say extremely low bass or extremely high frequencies, will fall off.
Now 16 bits is more than enough for most commercial music streamed online. But since you're a producer, you want a…bit more (you see what I did there?).
Most better quality audio interfaces will support at least 24-bit depth. This gives you a 24 x 6 = 144dB of range. This is more than enough for virtually any audible sound.
As a general rule, stay away from audio interfaces that support only 16-bit audio. You want 24-bit minimum. Even better if it supports at least 96kHz of sampling rates.
Preamp: The analog signal from a microphone is usually too weak to be captured directly by an audio interface. It needs to be pushed up before you can record it.
This is why most audio interfaces have mic preamps built into the units. These preamps are connected to the XLR port and amplify the signal before recording.
The preamp can range a great deal in quality. Behrginer, for instance, offers MIDAS preamps in its $100+ interfaces. Its cheaper interfaces, however, use the XENYX preamp. The latter isn't nearly as clear as the former.
Once again, try to get an audio interface with the best possible built-in preamp. But don't obsess over it too much. By the time you get to pro-level gear (anything over $500), you'll ideally want a standalone, dedicated mic preamp anyway, undercutting any advantage the built-in pre offers.
Besides the above, you should also consider whether your interface supports phantom power. You need this to power-up passive condenser microphones. Most units will usually offer 48V of phantom power.
What are some other things to consider?
In addition to the above technical specifications, also consider the following:
Form factor: Smaller audio interfaces are better in case you have limited desk space. They also make it easier to carry the interface from gig to gig and studio to studio.
In case you have an audio rack mount, you'll want a rackmounted interface.
Usability: A large volume knob and carefully placed ports greatly enhance usability. Ideally, the audio interface should have at least 1-2 easily accessible ports placed up front. This will allow you to connect microphones/guitars/MIDI instruments without fiddling with cables at the back.
Studio monitor outputs should be at the back of the interface, but you should get a 1/4″ or 1/8″ headphone out in the front.
Dedicated gain knobs for individual inputs are also a nice touch and enhance usability.
Compatibility: Consider whether the audio interface is compatible with a) your operating system, and b) your DAW.
While most audio interfaces will work with the latest versions of Windows and Mac OS, some might not work with Windows XP/7/8. If you're using these operating systems, make sure that your choice of interface supports them.
Similarly, most interfaces will also work with newer versions of popular DAWs. You do have to look out for compatibility issues if you're using an obscure DAW or a very old version of a popular DAW.
With that, we come to a close in this extended guide to buying the best USB audio interface. We’ve covered everything from the factors that should impact your purchase decision to a comprehensive list of the best interfaces on the market right now.
Just to recap, here is our list of the best USB audio interfaces, sorted by category:
- Focusrite Scarlett 2i2 (Best overall)
- Behringer UM2 Audio Interface (Best value)
- Audient iD4 (Best performance – solo)
- Arturia AudioFuse 14 x 14 (Best performance – home studio)
- IK Multimedia iRig Pre HD (Best for mobiles)
- Focusrite Scarlett 18i20 (Best rackmounted)
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