Audio interfaces are among the most important components in the audio signal chain as far as recording is concerned. Yet, oddly enough, they are also among the most oft-neglected, especially among beginner recording engineers.
Almost everyone who got into recording in the age of the computer started out using the onboard soundcard. We’ve all been there. After all, what could be easier than plugging in a mic or guitar into a computer’s ‘line in’ port?
Of course, many of us realized sooner or later that the resulting audio recorded in this manner was far from optimal quality. I mean, let’s not mince words: it was garbage.
Even so, many amateur singers, hobbyist musicians, and recording enthusiasts simply made do with what they had. Many simply stuck to recording their music straight through their computer’s audio interface due to ignorance, insufficient funds, or both.
We’re not going to go into all the reasons why YOU ABSOLUTELY MUST USE AN AUDIO INTERFACE instead of recording directly into your computer’s soundcard. That isn’t the focus of this article. But if you must know, please check out this article by the Musician’s Institute. That should tell you all you need to know about why you need an audio interface.
Do audio interfaces sound different from each other?
So what is the purpose of this article? As you may have guessed from the title, we tackle the question: “Do different audio interfaces sound different from each other?” It’s a loaded question to be sure, and getting to the bottom of it could potentially affect some of the most crucial purchase decisions you will make as a recording engineer.
The short answer is: “Yes.” Different audio interfaces do sound different from each other. But whether those differences affect the quality of the recording significantly is another matter entirely.
Factors that affect the sound of your audio interface
Let me clarify. Audio interfaces have several different components, each of which could potentially affect the sound as you record it and play it back. The input chain begins with a preamp, which amplifies the signal from mic and line level devices. Without this preamp, the signal from your mic or electric guitar will be too low to be recorded properly.
From there, the audio signal passes through an analog-to-digital (AD) converter. This transforms analog signals into digital format, which your computer software can capture and process.
That’s the basic function of an AD converter. There is also a “DA,” which converts digital information into analog audio so that your speakers can reproduce it.
If you want to learn more about AD/DA converters, have a look at this article from Soundgirls.org. But, be warned: it’s pretty technical stuff!
Okay, so those are the two most important components of the input stage of a typical audio interface. Any perceived differences involve these particular parts. The differences between preamps are more apparent, so let’s tackle those first.
The preamp
Going back to the onboard soundcard of your computer, part of the reason why recordings made with them sound so bad is that they use the cheapest and lowest quality preamps available. Unfortunately, these consumer-grade components do little more than amplify the signal, often with a good deal of noise and electrical interference added to the mix.
At this point, it has to be said that preamps shouldn’t add any type of ‘color’ or ‘character’ to the recorded audio…at least in theory. Although preamps are supposed to capture audio as cleanly and clearly as possible, some of them do add a bit of coloration or harmonic distortion, which may not necessarily be a bad thing.
Some would argue the point, but the preamps in Behringer’s UMC404HD sound different from those in the Steinberg UR44 and the Focusrite Scarlett 2i2. We go over the qualities of each device in our rundown of The 10 Best Audio Interfaces For Home And Project Studios. But for now, suffice it to say that the differences in these devices’ preamps do affect the character of the recorded audio.
The AD converter
The other crucial component is the AD converter, which, as you will recall, transforms the analog signal into bytes and bits that your computer can understand. This actually has less of an effect on the audio character, as differences between converters tend to be negligible.
Now, we realize that might be a controversial statement, but hear us out. In the budget to mid-level audio interface market, AD/DA converters are pretty much the same for all practical purposes. Therefore, you aren’t likely to hear a difference between the various devices in our roundup if you solely base your test on the AD converters.
Sure, you can spend a lot more on a high-end audio interface and get higher-quality AD/DA conversion. But you are unlikely to hear a significant difference because you are still monitoring the audio through your budget to mid-range speakers in a less than optimal acoustic space.
Should you spend on a more expensive audio interface?
Hold up. Does this mean that it doesn’t matter what type of audio interface you use? Not quite. Sure, you could get decent recordings with the cheapest audio interface in our lineup, which is the PreSonus AudioBox USB 96, by the way. In fact, in a blind test, you probably won’t be able to tell the difference between that and a Focusrite Scarlett 18i20 or a Universal Audio Apollo Twin MKII SOLO, both of which cost about $500.
*But* there are other factors to consider. For example, more expensive audio interfaces have more inputs, cleaner signal paths, better build quality…the list goes on. So while you can use a cheaper audio interface and still come up with awesome-sounding recordings, don’t discount the benefit of upgrading to a better and more expensive interface.
Do these differences matter?
Okay, brass tacks. We’ve already established that audio interfaces may sound different as far as the recorded audio goes. But do these differences really matter? Are they significant enough for you to choose one audio interface over another?
The truth is, you pretty much can’t go wrong with any of the audio interfaces covered in our rundown. Any differences between preamps are marginal at best and probably won’t affect the sound in a way that you can hear without a much higher-end monitoring system.
The bottom line is this: if you are shopping for an audio interface, it might be more important to focus on factors such as number of I/O, preamp type, stability, compatibility, and performance, rather than on minuscule differences in sound.
