CEntrance MixerFace R4B Mobile Audio Interface
& SD Recorder
By Drew Robertson
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...
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.
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 [email protected]