The Ultimate Guide to Audio Interfaces
Everything you need to know to pick the interface with the best sound and specs for your production setup.
FEBRUARY 3RD, 2023
When you look up audio interfaces, there are some key concepts you’ll need a little bit of knowledge in so you can determine which ones meet your needs; the most basic ones are sample rate and bit depth. Sample rate refers to the number of samples, or snapshots of a specific moment in an audio signal, that occur in a single second. The highest frequency audible in an audio signal is exactly half the sample rate, meaning at 44.1kHz, the frequency cap is 22.05kHz. Using sample rates higher than this has two primary benefits:
- Every audio signal must be low-pass filtered to prevent digital artifacts called aliasing from bleeding into the signal. Harsher filters with stronger slopes filter out more high frequencies at the cost of greater phase smearing, which reduces the perceived resolution. Higher sample rates allow for gentler filter slopes, leading to greater signal clarity overall.
- The higher the sample rate, the more information above 20kHz is preserved, meaning you can pitch audio files down further without losing any perceived high-frequency content (which is why sample packs are often exported at 96kHz)
Next on the list is bit depth, which is simply amplitude resolution; fewer bits lead to more prominent “steps” or “stairs” in the audio, introducing harsh distortion. The minimum number of bits required to faithfully reproduce a normal-level signal is 24, though if a 24 bit signal is exported at a quiet volume, you’ll likely hear audible “quantization noise”, which is the distortion mentioned above.
It’s fairly common to see 32 bit floating point now; that’s a more complicated subject, but all you need to know is that even quiet audio will typically be preserved in full clarity. Many DAWs run 32 bit floating point summing in the background to keep all signals clean and avoid digital clipping, even when they render at lower bit rates.
Before we move into individual audio interfaces, there’s another important topic in the world of audio quality: digital to audio (or DA) conversion. Most audio interfaces have DA converters to turn data into an electrical signal that can be played back as audio, but no converter is perfect. Poor converters can make audio sound flat and lifeless, and it’s difficult to quantify exactly what you’re missing until you hear the sound of an excellent converter.
The best converters are often standalone devices that don’t offer audio inputs and go around $2k and above. Don’t worry though, most interfaces have perfectly serviceable DA converters; the difference in cost and lower functionality isn’t worth it until you already have top of the line monitors and a treated room, so just do enough research to make sure your interface sounds good enough for your current needs!
If you’re on a budget and just need an interface that does the job right, the Focusrite’s Scarlett is a great tool for the job. It’s notably less expensive than the other interfaces we cover in this article, but it can still handle sample rates up to 192kHz so you’ll never be at a loss for high quality recording. Don’t let the price point fool you — it makes a great starter interface despite its affordability.
Universal Audio Volt
The UA Volt is a great lightweight entry-level audio interface. It has 2 inputs, which is common among bedroom interfaces, but it has a few tricks up its sleeve to provide an authentic vintage sound, including onboard 1176-style compressors and a “vintage” mode to add some warmth to your recordings before they even make it into your DAW. It sells at a fantastic price for such high audio quality and analog hardware processing.
It’s more expensive than the Scarlett, but if you do a lot of home recording and want a more professional, studio-quality sound, the added coloration options can make it worth the difference in price. Plus, the Volt is lightweight and compact, and the wood frame gives the impression of a higher-end interface; from a design standpoint it’s hard to beat, plus it comes with a couple UJAM plugins to boot!
A favorite for on-the-go producers who value compactness and simplicity but want better DA conversion than they can get from a laptop. Sound quality is where the Duet shines, which is impressive given its size. This even extends to its mic preamps, which are known for their extensive headroom and clean gain. Its slimness makes it incredibly easy to travel with, but this deceptively small interface is known worldwide for its excellent audio quality. The Duet marks another step up in price, but if you want to get the DA conversion and mic pres you can without breaking $1k, it should be a serious contender in your research!
This is very clearly a heavyweight option and not aimed at bedroom producers — Avid’s Carbon interface is comparable with some of the best interfaces on the market. We’ve elected to include it not as an option to purchase, but to show what interfaces look like in larger studios.
One notable point is that the Carbon has the capacity for capturing 32 bit recordings, providing effectively infinite resolution for everything that enters your system, which is rare among audio interfaces (typically this bit depth is only handled internally in DAWs). It also has 24 mic/line inputs, 4 headphone outputs, and overall more I/O capabilities than you’ll ever need in a bedroom studio. Perhaps most significantly, it has hardware-accelerated DSP capabilities — meaning you can offload much of your DAW’s processing needs to the Carbon, freeing up tons of CPU resources as long as you’re using Pro Tools. While it works with other DAWs, the hardware acceleration is specifically for AAX plugins, Avid’s proprietary format.
There’s no shortage of excellent audio interface options available, and we’ve only scratched the surface. How far you choose to go in terms of quality and versatility is a highly personal decision, as the options range from ~$100 for decent quality to multiple thousands for fantastic results. At some point, only a highly attuned ear can tell the difference, so don’t rush to get the most expensive option you can unless you know it’s worth it for you. Besides, your monitors are the truest test of the quality of your setup!
About the Author
Harry Lodes is a copywriter, marketing consultant and content writer for audio and ecommerce brands. He lives in the Philadelphia area, releasing Eastern/Western hybrid EDM under the artist name KAIRI hearkening back to his roots in Berklee College of Music.
We develop software solutions that enable people to create, consume and interact with music.