Mobile recording interfaces are often hobbled by the need for external power sources. While it’s usually possible to find an AC outlet, genuinely portable field recording with condenser microphones can pose serious challenges. There are several mid-level units that offer USB power, but at the high-end, finding a capable battery-based interface with 48V compatibility is tricky.

Accordingly, CEntrance’s new MixerFace R4 is an extraordinary achievement. Their other products have received glowing praise from both professionals and journalists thanks to their ridiculously clean Jasmine Mic Pres. After spending a week with the unit and my trusty Audio-Technica condenser, I’m inclined to agree. The audio specs and dynamic range of MixerFace R4 is striking and worthy of its accolades.

While the device works with Mac and Windows, even more noteworthy is its compatibility with iOS via Apple’s Lightning to USB adapter, which is required for connecting to your iDevice. I do most of my field recording using a dedicated recorder, but with this unit, I can now capture directly to my iPad. I tested it with both Kymatica AUM and Korg Gadget and it performed beautifully at a variety of sample rates and resolutions. It’s also friendly with the Android platform, if that’s your preference.

Analog audio connections are handled through a pair of balanced Neutrik connectors for XLR or 1/4" sources. There is also a stereo aux input for chaining mixers or adding another source. In addition to 48V phantom power for both combo inputs, you'll find independent controls for Hi-Z and a 130Hz highpass filter for each, so customizing for a microphone on one and an instrument on the other is painless.

On the output side, there are two balanced outputs on 1/8" jacks, which will necessitate adapters in some cases, but the superb quality of the pre-amps and DACs offsets this greatly. The headphone amp is another highlight of the unit, with the same transparency as CEntrance’s other products, which have amazing headroom and are beautifully clear. Switching back to my iPad headphone jack made this instantly apparent.

The converters offer sampling rates and resolutions up to 32-bit/192 kHz (which Kymatica AUM supports). I generally record at 24-bit with lower sampling rates, but it’s nice to know the MixerFace R4 will remain technologically relevant for the foreseeable future.

As for battery life, it’s ready for marathon sessions out of the box. I spent a night using it as a headphone amp with occasional miking to see how long it lasted and with a full charge I still had juice after five hours when I stopped. Using phantom power with my condenser mic, the results were similar. CEntrance says you should expect to get between 7-8 hours per session (and clever users can bring a larger USB phone battery bank for on-the-spot charging if they have range anxiety).

All in all, the MixerFace R4 is spectacular for mobile recording if you need professional-grade mic inputs and phantom power. And while it’s designed as an interface, you can skip that entirely and just use it as a gorgeous preamp, making it a shoo-in for video applications, too.

At first, I thought the $349 price tag was a tad high for the iOS crowd, but factoring in its standalone uses and laptop compatibility, the CEntrance MixerFace R4 seems like a bargain now.

Strengths: High-quality mic preamps. 48V phantom power. Independent hi-Z inputs. and low-cut (HPF) for each input. Integrated LiPo battery with impressive life.
Limitations: Lightning-to-USB 3 adapter required for iOS