PRODUCT TESTS CEntrance MixerFace R4B Mobile Audio Interface & SD Recorder By Drew Robertson L et’s take a close look at the MixerFace R4B from CEntrance, a com- pact, lightweight, battery-operated recording interface for the recording engineer, videographer, or content creator on the go. Overview & Features The MixerFace is a very well-put-together piece of hardware, coming in at 12 cm long and weighing only 120 g (4.5 inches and 4.2 oz for those using freedom units) with an all-metal construction. The chas- sis is comprised of two halves held together with hex screws, with separate plates covering the front I/O and rear controls held on with smaller screws. Why does this matter? Well, because it means you can easily and quickly disassemble one and make a repair if necessary – a must feature on any professional piece of audio gear I intend to use in the field. Speaking of features, the MixerFace has been loaded to the gun- nels with them. On the front, you’ll find two custom Jasmine preamps with Neutrik XLR combo jacks as well as two balanced 3.5-mm out- puts. The top of the interface is where you’ll find your recessed micro switches for Hi-Z input and hi-pass filters, gain pots, USB blend pots, the aux input control, and monitor control. You’ll find the rest of the controls and I/O on the rear of the device. The top row consists of the playback controls and microSD slot. The playback controls are satisfyingly robust and well-spaced so that you won’t accidently hit more than one at a time – no small feat on something this compact. Below that, you’ll find the USB I/O connec- tor, line in, line out, headphone out, battery indicator, and separate USB charging/mounting port. Last but not least, you’ll find the 48-V phantom switch, mono collapse switch, line level switch, and power button. On the bottom, you’ll find a quick start guide and a convenient 3/8-in. mounting point. The action of all the control knobs is very satisfying; they’re also rubberized so you get a clean grip to their surface and the large indicator stripe makes them easy to see even in the dark, although I would appreciate a gain scale with actual numbers The product ships with a SIM tray tool to operate the micro switches dotted about the body. Thankfully, none of these switches is associated with a feature you are likely to need rapid access to, so it’s a fair compromise given the limited space on the device. The MixerFace R4B model also comes with a pair of condenser mics configured for X/Y stereo recording. They’re also made of metal and sound excellent. They fit into the interface snuggly and have no play or wiggle, so you won’t pick up any ambiguous movement noise when handling the interface. Nicely done, CEntrance. One of the prime focus points of the MixerFace R4B is its ability to interface with a mobile device and provide you with high-quality audio, which you can then stream to YouTube, Instagram, or other platforms of your choice. More on that later... In Use Once you acquaint yourself with the controls, you’ll likely want to connect your MixerFace to your mobile device. For this, you’ll need the appropriate adaptor or cable for your device. Armed with a micro USB-to-appropriate opposite connector cable, you can plug the unit in, power it up, and get right to streaming. It re- 24 PROFESSIONAL SOUND ally is that simple! I got a little prompt on my device asking if I wanted to use it for audio, and once allowed, it worked just fine. Dead easy. Now, let’s examine the MixerFace as I actually intended to use it: as a super-light field recorder for video shoots. It was easy to mount to my Lumix GH5 and route a short audio cable from the rear of the device to the camera input. Audio pass-through was clean and clear and the fact that I could simultaneously record audio to the onboard microSD was great. One thing to keep in mind is that the MixerFace will only record stereo files, unless you’re using it as an interface with software on a computer or mobile device – not a big deal if you are using the XY capsules; however, I was using two mics in different positions and thus had to split the audio into separate left and right tracks in post. Again, not a big deal, but something to be aware of, and perhaps in the future, CEntrance would include mono recording ability for the individual channels along with the stereo mix. Regardless of that workaround, the fact that I can both send audio to my camera or live stream while simultaneously recording the audio directly to the device is excellent. It’s a built-in back-up system, which any serious creator will appreciated. Summary The MixerFace R4B from CEntrance is a unique, micro-sized studio for the professional on the go. Whether it’s used for live steaming, record- ing your band’s live gigs, or capturing crystal-clear interview audio, the MixerFace can tackle it all with ease and a refreshingly low-impact footprint. I was pleasantly surprised by the robust build quality and simple-to-use controls. The Jasmine preamps are smooth and clear with no distortion to the audio over the gain range. None of the ports conflict or interfere with one another either; it’s all rather well thought out. There’s really nothing bad to say about the MixerFace; CEntrance really got it right. If you’re in the market for a mobile interface on a reasonable budget, I would handily recommend the MixerFace R4B for your needs. Until next time, happy mixing! Drew Robertson is a freelance audio engineer, independent broadcaster, and live sound specialist based out of London, ON. He can be reached at RobertsonAudioPost@protonmail.com.