If you’ve ever wondered why someone would spend $1,000 or $3,000 on an audio interface when they could get an interface for less than $200, read this until the end.
I’ve experimented with a wide range of audio interfaces, especially throughout the process of creating these videos for you, and along the way, I’ve discovered that some of the most important features of an audio interface can easily go overlooked.
Thank you to RME for sponsoring this video and supporting audio education.
I’ve got two stations in my room because I have two very different tasks that call for different workflows: music production and content creation. Each station has its own audio interface because each station calls for different functionality. That’s a very important point in this discussion: the interface depends on YOUR needs, YOUR preferences, and YOUR workflow.
Here are a few things you should consider…
Inputs & Outputs
Let’s start with the inputs and outputs (or “I/O” for short). This includes all of the analog and digital connections for getting audio signals (and maybe even other types of signals) in and out of the device.
Common connections for analog audio signals in pro audio are TRS and XLR. But you should look beyond the connector that’s used and verify the type of signal each input can take.
The analog connections on the RME Babyface Pro FS include two XLR microphone or line level inputs, two TRS line or instrument level inputs, two XLR line outputs, a ¼” headphone jack, and an ⅛” headphone jack.
Over on the side, there are two optical connections for ADAT. These connections offer an additional 8 channels in and 8 channels out!
You may see the additional XLR connections on the RME Fireface UCXII and assume that they are also microphone inputs when they are really a digital connection called AES-3. The RCA connections are used for a digital connection called SPDIF. Both of these connections support 2 channels in and 2 channels out.
Utilizing the digital connections on interfaces opens the door to a lot more I/O right now or the opportunity to expand your I/O in the future. For example, I’ve got two microphone inputs, but I frequently need more mic inputs. Rather than replacing my interface, I’m able to simply add an ADAT-enabled microphone preamp, connect it to Babyface Pro FS with an optical connection, and now I’ve got 8 additional microphone inputs.
For studios and facilities that require even more inputs and outputs on an audio interface, you may see protocols like AVB, MADI, and Dante. These allow you to send and receive anywhere from 32 channels up to hundreds of channels of audio. Check out this post about Expanding Your Audio Interface with ADAT, MADI, and Dante.
If you need a lot of I/O, you’re going to end up paying more. I think everyone understands that. Buying a simple 2-channel interface with no expandability will naturally cost less than an interface capable of managing 16 channels, which will cost less than an interface capable of managing hundreds of channels. But there are some features that aren’t seen on the surface – and they’re just as important.
Software & Drivers
Often overlooked is the quality of an audio interface’s drivers and software. This might be the most important factor that determines the true value of an interface, alongside the physical I/O.
The driver is responsible for transporting digital audio to and from the interface. More than anything else, this impacts the round-trip latency and reliability of an interface.
The Babyface Pro FS is a USB 2.0 interface which, in my testing, had a round trip latency of around 3.8 ms.
As you get into larger channel counts, you’ll start to see other connections like USB 3.0 and Thunderbolt. For anything below about 60 channels though, USB 2.0 provides plenty of bandwidth. Check out this video about
Assuming your computer is adequately powered to facilitate the plugins and processing within your session, you can lower your session buffer size and monitor your recordings in real-time with very low latency or delay.
At a certain point, you may run into the limits of your computer’s processing power. Then you’ll need to either bypass the plugins in the session or monitor through a lower-latency signal path.
Lots of interfaces have a direct monitoring feature, and while that provides a low-latency signal from the microphone or instrument you’re recording, you’re stuck with the dry signal – no eq, reverb, or other FX. Having reverb, compression, or EQ in headphones can be very helpful for a performer, but that’s not possible with basic direct monitoring.
Some interfaces solve this problem with a proprietary DSP chip or an FPGA-based DSP that can process the audio for real-time monitoring without the need to pass through the DAW session. This is helpful for making a monitoring mix, but as you’ll see in a moment, the utility actually goes far beyond that.
The software that controls RME interfaces is called TotalMix, which comes free with the Babyface Pro FS.
As I said, I can easily set up a monitor mix for a performer by selecting the mix that feeds their headphones and adjusting the sends on each input channel that I want them to hear. Then, I can adjust the FX send on each channel to a built-in reverb and send the FX return to the headphone mix as well.
TotalMix allows me to send any physical input (or any software input) to any physical output. That makes this interface very flexible.
As you can imagine, I frequently set up different signal flows and screen captures for my videos. So having 20 mono outputs (or 10 stereo outputs) at my fingertips is extremely useful. I can use it for creating sub-mixes for live streams, for setting up demonstrations, and for doing screen recordings.
A key feature that I use all the time is Loopback. Any audio from a physical source (like a microphone or instrument), any audio playing from another program on my computer (like YouTube or a DAW) can be routed back into OBS, Zoom, a live stream, or a DAW as an input.
This means I can create a custom mix for the audience on a live stream, with EQ and FX already applied, a custom mix-minus for a remote guest, a custom mix for myself, and send each channel to a separate track in a DAW, all from within TotalMix.
The point here is that when you look at the physical I/O on an interface, that’s only half the story. An interface with a powerful software component (like RME’s TotalMix) can act as a virtual mixing console and patch bay for your studio.
I’m even able to use the TotalMix Remote app on my iPad to control all of this over my WiFi network. I often use this to run my session when I’m recording myself or to give a performer a custom set of controls for making their own headphone mix.
This interface (the RME Babyface Pro FS) is bus-powered, which means it gets its power from the USB connection to the computer. But the RME UCXii and UFX interfaces run off of wall power, which facilitates some additional DSP resources for compression on every channel and room EQ and delay on every output. That means you could set up and tune an immersive audio system, all within TotalMix.
Beyond low-latency performance and flexible routing, great drivers also contribute to the reliability and stability of an interface. This is a very important point to consider when you’re building a system for professional work.
You definitely do not want your interface or computer to crash in the middle of a session. That could cost you not only time, but in this business, it could interrupt a live stream or a great performance. Stability is worth the investment, especially in professional settings where malfunctioning equipment could cost you your job.
The RME UCXii is currently controlling my filming and live-streaming station. It offers all of the functionality I’ve discussed so far, plus a feature that I overlooked at first but protects me from accidentally sabotaging my own sessions.
When I sit down, I immediately hit the record button in TotalMix, which records every input and output as a separate track on this 2TB SSD. That means if the computer or the session does crash, I’m still covered. And when a performer nails a part while rehearsing and it’s not rolling or if I ever forget to press record, I can just go back and recover those moments.
I’ve got a few more important features to share with you in a moment, but the final point I’ll make about drivers is that they need to constantly adapt over time. If there is a big (or even a small) change to your computer’s operating system, you’ll probably need an updated driver for your audio interface to function properly.
Some interfaces from 10 or 20 years ago simply do not work today. That’s because some developers stop supporting older models. That means you either need to stay on your current Windows or Mac OS operating system forever or you need to buy another interface with drivers that are compatible with the new operating system.
A great audio interface company will keep a close eye on potential bugs that could arise when Microsoft or Apple updates their operating systems. But RME, in particular, takes this a step further than most companies by supporting their older interface models as well.
For example, the RME HDSP 9652 was released in 2001, but it still has up-to-date drivers that were published this year. When you invest more money into your audio interface, you should expect it to last you a long time – not just a couple of years.
Key Specifications
While the physical I/O and drivers are probably the most important factors to consider when deciding which audio interface to invest your hard-earned money into, you’ll also want to consider the quality of the inputs, outputs, and conversion.
Before we go there – I’ll first say that you can’t solely rely on technical specifications. You should aspire to build your skill set to the point where you can make great records with any gear.
Interfaces these days are pretty impressive – the standards of quality in even the least expensive interfaces are relatively high, compared to the standards just a few decades ago. But there are a few hidden specs that you might miss if you don’t specifically look for them.
Again – these won’t make bad recordings sound good, but they can certainly help you take great recordings to the next level.
For example, all microphone preamps are not equal. The Babyface Pro FS has a gain range of 76 dB, with the ability to provide up to 65 dB of gain when needed. Plus, the mic inputs have a signal-to-noise ratio of 117 dB A-weighted. This is important for capturing clean, low-noise recordings when using a low-sensitivity microphone or when recording relatively quiet sound sources.
Be sure to check the dynamic range or signal-to-noise ratio of the instrument inputs, line inputs, line outputs, and headphone outputs, as well as the power specs of the headphone outputs to ensure you can adequately power any headphones you might be using, regardless of sensitivity and impedance.
Analog-to-digital converters (or ADCs) and digital-to-analog converters (DACs) can also vary in their dynamic range and jitter specs. The “FS” in RME Babyface Pro FS stands for “femtosecond”, indicating that it has extremely low jitter and high jitter immunity, which can level up all of the gear you have digitally connected in your studio.
When you’re investing in an audio interface, consider not just the TYPE or QUANTITY of I/O, but also the QUALITY. And remember – don’t judge a book by its cover. The software behind the hardware may be where you find the most value for your money.