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RME Fireface UFX

USB & Firewire Audio Interface
Published January 2011
By Hugh Robjohns

RME have established a solid pedigree for their extensive range of digital interfaces. Their latest model offers powerful functionality, and promises an unexpected extra for the future...

RME Fireface UFX

The UFX has been designed to serve not only as a very flexible audio interface, with comprehensive input selection, onboard signal processing, but also as a versatile monitor controller and headphone amp. It even has talkback switching and routing facilities built in, using any nominated inputs as talkback and listenback mic sources. There are a total of 30 inputs and another 30 outputs (12 analogue and 18 digital at standard sample rates), plus two independent MIDI ports. It has four digitally controlled mic preamps derived from the high‑end Micstasy, and a high‑quality, dual‑paralleled, A‑D converter topology to provide up to 192kHz operation with excellent dynamic range and distortion figures. Unusually, the UFX can be hooked up to a computer using USB2 or Firewire 400 — the USB implementation is claimed to be compatible with USB 3 interfaces, and the Firewire port can be used with Firewire 800 interfaces via a standard converter cable. The Firewire interface is actually driven from an RME‑designed FPGA (Field Programmable Gate Array) rather than a standard Firewire chip, too, to ensure maximum compatibility with all Firewire interfaces — even the often problematic Agere chips! RME's own reliable and ultra low-latency drivers and the SteadyClock active jitter-suppression technology complete the headlines.

RME's impressive Digi Check metering and analysis toolbox software is also included, along with the new TotalMix FX application, a 42‑bit digital mixer and signal router. Powered by two onboard DSPs (to reduce the load on the host computer), this provides a three‑band EQ plus high‑pass filter, full dynamics, and M/S processing on every physical input and output, plus reverb effects. ASIO Direct Monitoring is also supported, of course, and all of these features can be controlled directly from the UFX's own display screen, if required, allowing stand‑alone operation. A planned future firmware upgrade will also enable direct recording to a USB memory stick or hard drive. All in all, then, this looks to be a very cleverly designed, and well thought-out new product!

Guided Tour

If there were a prize for squeezing the most inputs and outputs into a 1U rack device, RME would certainly be in the running....If there were a prize for squeezing the most inputs and outputs into a 1U rack device, RME would certainly be in the running....

Packed into the box along with the smart, 1U, rackmounting UFX (the rack ears are removable) are USB 2 and FW400 cables (1.8 and 4 metres long, respectively). There's also one Toslink optical cable (2m), a mains cable, a driver CD and a substantial manual. Thankfully, the manual isn't quite as scary as it looks, because it's bi-lingual (German from one end and English from the other), and includes separate sections for Mac and PC software installations. It's still a meaty read, but well written and (mostly) understandable. The UFX ships with drivers for Windows XP, Vista and 7, as well as Mac OS X, with updates available on the company's web site.

The rear panel of the UFX is pretty busy, hosting eight balanced line inputs on quarter‑inch TRS sockets, plus eight balanced line outs. The first pair of these is via XLRs, with the rest on more TRS sockets. Another pair of XLRs handle AES3 digital audio I/O, and two sets of ADAT lightpipe are included. S/MUX2 and S/MUX4 ADAT modes are supported, allowing four channels at 96kHz and two channels at 192kHz.

Word clock I/O is provided on BNCs, the input having a switchable 75Ω termination, and USB 2 and FW400 sockets provide connections to a host computer. A mini‑DIN socket caters for an optional remote (the same one used with RME's own high-end ADI-8 QS preamp and A-D converter), providing Volume, Dim, Store and Recall functions. A pair of MIDI sockets and an IEC mains inlet (for a universal power supply accepting voltages between 100V and 240V AC) complete the rear-panel facilities.

The powder-blue painted front panel with white control legends carries four 'combi' XLR‑jack inputs for mic and Hi‑Z instrument/line inputs (channels 9‑12), with LEDs to indicate signal present, phantom power activated, and TRS input mode. A pair of TRS sockets provides unbalanced stereo headphone outputs (channels 9&10 and 11&12), while a second set of MIDI I/O sockets occupies the centre of the panel, along with a USB socket. Although not active in the current firmware, this socket is intended to accommodate a memory stick or hard drive to allow direct recording and playback functions potentially making the UFX very attractive as a mobile recording device!

An array of 10 LEDs indicate the unit's operating state, with sync status for each digital input (word clock, AES3, ADAT 1 and 2, USB and Firewire) denoted by green LEDs and MIDI activity by a yellow one. The operational controls at the right‑hand side comprise one large and two small rotary encoder knobs, four function buttons, and a small but high-resolution colour display. All three encoders have 'press switch' functions, and a rocker switch powers the unit.

In Use

The TotalMix FX software with the EQ and Dynamics windows open at the top of the screen.The TotalMix FX software with the EQ and Dynamics windows open at the top of the screen.

The Fireface UFX is very easy to set up. After connecting it to the computer (I tested both interfaces, but mainly used USB2), the appropriate driver is located automatically from the supplied CD‑ROM and quickly loaded. If required, the TotalMix FX and Digi Check software (see box, left) can be loaded too, and there is a flash update program that can be installed to load new firmware editions. I upgraded the review unit from Firmware version 333 to the current 338.

With the drivers installed, the UFX can be configured from a dedicated setup application. This allows the buffer size to be set and the second ADAT ports to be configured as optical S/PDIF connections, enables the EQ and dynamics in the record path, and sets the clock source and sample rate. It also indicates the sample rate and lock/sync status of each digital input, and allows the channel and status bits of the AES3 or S/PDIF output to be set for professional or consumer modes. There's also a ±5 percent pitch-correction facility (with coarse and fine adjustment options), and all the sample rates necessary to accommodate the 0.1 and four percent pull‑up and pull‑down modes involved in PAL/NTSC and film transfers are available.

With the unit suitably configured, operation from the front panel is pretty intuitive, although I took a few moments to figure out the navigation logic, which uses the two smaller rotary encoders and their 'press switch' button actions to select, navigate and adjust menu items. The small display is crisp and clear: even the meter page, with 60 bar‑graphs, has excellent resolution and clarity.

By default, outputs 1&2 are allocated to the main monitoring path, and controlled by the larger rotary encoder. This is the normal operating mode, which the unit reverts to if there's no further menu‑related activity. Pressing the large encoder toggles through the two headphone monitoring outputs (9&10 and 11&12), adjusting their levels independently. Other functions are accessed by pressing the buttons alongside the screen. An example is gain adjustment for the four mic inputs (spanning a 65dB gain range controlled digitally in 1dB increments), which is done by pressing the first button and then using the small encoder knobs. The second button displays bar-graph meters for all physical inputs and outputs.

The third button, labelled Channel, is where most of the configuration is done. Through this menu, each physical input and output can be configured. Submenus access settings (mono/stereo pairing, muting, effects send level, M/S processing, polarity inversion, and input sensitivity), low-cut filter (on, turnover frequency and slope), parametric EQ (on, frequency, gain and Q for each of the three bands, plus shelf or bell modes for the top and bottom bands), Dynamics (the usual comprehensive parameters for both comp‑lim and exp‑gate sections), and an Auto‑Level mode. The final button accesses Setup options, configuring such functions as clocking, control-room output allocations, saving and recalling of configuration setups, and the reverb and echo parameters. Everything can also be controlled and configured from the TotalMix FX software, or via MIDI using the Mackie Control protocol.

Sound Stuff

Digi Check is a multi-function metering application with nine different modes, including the Vector Audio Scope shown here.Digi Check is a multi-function metering application with nine different modes, including the Vector Audio Scope shown here.

In terms of sound quality, the UFX is one of the best interfaces I've used. It's not quite up there with the Prism Sound Orpheus, but then it doesn't cost as much either. Nevertheless, detail, transparency, neutrality, resolution and depth are all terms that I'd use to describe the sound quality. Stereo tracks were replayed with a very stable, expansive stereo image and a smooth, natural tonality. Nothing ever sounded harsh, and the noise floor was virtually inaudible in most applications. Borrowing the converter technologies from the ADI‑8 QS and M‑series products, as RME have done (see box below) has paid off. This is a very sweet-sounding interface.

Using the UFX with a beta release of SADiE 6 and Adobe Audition 3 (both via ASIO) presented no problems at all, both seeming happy to operate with latencies of around 48 samples. Recording from all 12 analogue inputs while replaying 12 channels simultaneously at 44.1kHz worked without any glitches, and the system performed flawlessly throughout the review.

I'm always a little dubious about digital volume controls, not because of any sound‑quality issues, but because of the risk of losing control if the computer crashes. However, because the monitor level control is performed by the UFX's own internal DSP, it should continue to function even if the DAW software falls over — so any nasty noises can still be turned down before the tweeters start blowing smoke rings at the ceiling! The monitor control facilities work well, with smooth level changes and nice auto‑dim functions when talkback is used. The headphone outputs are also very clear and surprisingly powerful, even with relatively insensitive headphones.


I am very impressed with the Fireface UFX — it packs a lot of functionality into a small box, with excellent sound quality throughout and superb controllability. The TotalMix FX software is better than some full‑function DAWs I've used, and even controlling the unit via its front-panel controls is relatively painless. Converter and preamp sound quality is a step above most multi-channel interfaces, and the built‑in signal processing and effects will be useful in many applications, easing the strain on the computer's resources — although you won't want to scrap your UAD plug‑ins...

While having only four mic preamps might be considered a limitation, I think the combination of I/O is well judged, and additional preamps can be patched in via the analogue line inputs or one of the ADAT ports if necessary. Some might complain about the small display screen, too, but its resolution and the simple, clear menus work very well together — and everything can be controlled from the computer or a MIDI controller anyway! Nit‑picking aside, this is a well designed, great sounding, and remarkably flexible interface that is as future-proof as you're going to find anywhere, and has even greater potential with forthcoming firmware updates. In short, the UFX sets a new standard in affordable multi‑channel interfaces.  


From a cost perspective, the Fireface UFX is pitched in the market directly against the likes of the Metric Halo Mobile I/O 2882 Expanded +DSP Firewire interface — although this is Mac only — and sound quality between the two is similar. However, the key factor in choosing between interfaces, for most users, is the particular blend of I/O and other facilities, and the UFX is unique in what it offers and the quality it delivers.

The Prism Sound Orpheus sets the benchmark standard for interface quality and has the same number of mic preamps, while the Apogee Symphony system, (also Mac‑only) is a potential if slightly coloured contender, as is the MOTU 828 MkIII. Other Fireface interface products offer variations on the theme and share some of the same technologies, including the same driver reliability and low latency.

Stand‑alone Mode

The UFX can also be used independently of a computer in stand‑alone mode, controlled entirely from the front panel or via external MIDI commands, and six pre‑defined configurations can be stored internally for instant recall of favourite setups.

For example, the UFX can be configured as a 12-channel A‑D and D‑A converter, as a four-channel mic preamp with A‑D conversion, or as a monitor or headphone mixer handling any combination of analogue and digital inputs. It could also be used as a digital format converter, transcoding between ADAT, AES3 and S/PDIF formats, or as a routing matrix with both analogue and digital I/O. With the promised firmware update, it will also serve as a stand‑alone audio file recorder.

I tested the UFX as a stand‑alone four channel mic pre, comparing it to my Focusrite ISA, SSL SuperAnalogue and GML 8304 reference preamps. While there were audible differences, mostly at the bottom end, the UFX mic preamps performed extremely well, with a clean, neutral sound character and plenty of detail. They are not quite as full bodied as the GML or Focusrite ISA, but they have considerable resolution and detail and a smooth high end, and they remain usefully quiet even at high gain settings.

TotalMix FX & DigiCheck

The TotalMix FX digital mixer application is fully interactive with the UFX's front panel controls, and when it's first launched, a dialogue box asks to synchronise settings between them. The default window arrangement provides three rows of faders, the top row controlling the inputs, the middle row the software playback channels, and the bottom row the physical outputs. The input and output channels all have buttons beside the faders accessing EQ, dynamics and configuration windows, which slide out to the right of the fader when activated.

The three‑band parametric EQ includes a separate high‑pass filter with variable slope (6‑24dB/octave) and turnover (20 to 500Hz). The dynamics page features a compressor and an expander, plus an auto‑leveller function, while the configuration window allows adjacent channel linking for stereo, adjusts the input sensitivity or nominal output level, flips the polarity, and allows the effects send level to be changed. The four mic channels extend these options with switches for instrument input (DI) mode and phantom power, and include a mic gain control. A separate matrix window allows the various physical inputs, software replay channels and effects processor outputs to be routed quickly and easily to the physical outputs and effects inputs.

In use, the EQ proved very effective, and the dynamics processing was surprisingly transparent, too. The inclusion of an expander‑gate mode in addition to the compressor‑limiter makes this an extremely versatile facility. The auto‑levelling function takes some getting used to, but it seems reasonably effective if you want to get tracks sounding louder than loud before you start! I was slightly less impressed with the reverb and echo effects. As vanity treatments for vocalists while tracking, they are fine, and the choice of rooms, halls and other spaces provides enough variety to let you find something to do the job, but overall they all sound just a little too mechanical for a high-quality mix.

The DigiCheck application is a neat multi‑function metering display that operates as a multi‑client ASIO host and can be used with any WDM or ASIO audio software that has inputs and outputs. There are nine main display functions, starting with a high-precision level meter providing peak readings (with oversampling to detect inter‑sample 'overs') and RMS readings, plus phase correlation. It can also be used to provide loudness metering, and can be calibrated to conform to the K‑system of relative headroom metering. There's an audio vectorscope mode and a surround audioscope option, modelled on the RTW 'house'‑style display, and a spectrum analyser is included, as are digital bit-analysis displays and channel status displays for AES3 and S/PDIF inputs. It's an impressive tool and one I found particularly useful and surprisingly configurable.

Technical Performance

RME's converters have always been a step above the average, and the UFX uses a similar A‑D converter stage to RME's high‑end ADI‑8 QS preamp and converter (based on a Cirrus CS5368 IC), with a dual‑parallel converter arrangement to achieve unusually high signal‑to-noise performance figures. The D-A stages are derived from those used in the RME M‑Series products (using a Burr‑Brown PCM4104 chip). In the UFX, these achieve a signal‑to-noise ratio of an impressive 118dB A‑weighted, with a THD+N figure better than ‑100dB — both being excellent figures. The A‑D side boasts an impressive performance too, with a signal-to-noise ratio of 115dB (A‑weighted) for the mic inputs.

Line-input sensitivity and output levels can be switched, individually, between three operating modes: lo‑gain, +4dBu and ‑10dBV. The equivalent analogue levels for 0dBFS in or out are +19dBu, +13dBu, or +2dBV (+4dBu), but XLR outputs 1&2 have an additional fourth option of +24dBu for 0dBFS, and the unbalanced headphone outputs (9&10, and 11&12) have only two options: high (+13dBu) and low (+2dBV). The output impedance of these is 30Ω, to better match headphones, rather than the 75Ω of the other outputs.

Published January 2011

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