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Ravenna Audio Interface By Hugh Robjohns


Merging's desktop network interface is endowed with vast monitor-control powers.

Swiss manufacturers Merging Technologies are highly regarded in professional circles for the quality, sophistication, and reliability of their high-end audio products such as the Pyramix DAW and the Horus and Hapi rackmount AoIP (Audio over IP network) interfaces. Although Merging's products edge towards the expensive end of the marketplace their innovative designs and state-of-the art technologies appeal to demanding professional customers.

We reviewed the Hapi back in March 2015, and last year, Merging added a new and significantly more affordable product to their range. The Anubis — named after the ancient Egyptian God of the dead — is a compact desktop AoIP interface that works either in a stand-alone mode or attached to a Ravenna network audio system (with up to 256 channels). It can also be used directly with standard DAWs on PC, Mac and Linux platforms. Again, it can be connected to the computer over a network connection, but is also accessible using ASIO, Core Audio or ALSA drivers as appropriate. The Anubis can even be remote-controlled over the web from smartphones, tablets or computers.

Although it is primarily designed to be used with Ravenna AoIP networks, the Anubis can also be configured to work with the AES67/SMPTE ST2110 protocols, which means it can work with Dante installations if they are also configured in AES67 mode (with some restrictions on sample rates). Interestingly, though, Merging's Ravenna interface card — ZMAN — is pin-compatible with Audinate's Brooklyn II card, which most manufacturers employ for Dante connectivity... so a full Dante version of the Anubis might be on the cards in the future, depending on demand.

Two distinct versions of the Anubis are available, identified as the 'Pro' and 'Premium' models. These variants are visually identical, with the same physical I/O, core features and facilities. The only difference at present is that the lower-cost Pro model is restricted to standard PCM sample rates, at up to 192kHz. The more expensive Premium version supports PCM rates to 384kHz, as well as DXD (352.8kHz) and all the DSD formats up to DSD256. Clearly, in a software-controlled product it would be straightforward for Merging to bestow the Premium model with exclusive additional functions in the future as the platform's capabilities are further developed — and the Anubis is very much a product in development: two firmware updates were released during the review period, taking it up to v1.019 at the time of writing.

Open The Box

The Anubis unit itself measures just 200 x 40 x 128 mm but it's surprisingly solid, weighing in at 950g, which makes it unlikely to be pulled off the desk by connected cables. The Anubis' chassis is machined from a single piece of aluminium, its design apparently aided by another revered Swiss audio manufacturer, Sonosax. Usefully, a 3/8-inch threaded insert in the base enables the Anubis controller to be stand-mounted, if required.

Supplied with the Anubis are a robust 'soft-shell' carrying case, a quick-start guide (the full 142-page PDF manual is only available online), an Ethernet cable, and a 12V line-lump universal power supply. However, the Anubis can also be powered via PoE+ (Power-Over-Ethernet-Plus or IEEE802.3at) from a suitable powered Ethernet switch, so the line-lump DC supply may not be needed at all, or it can be employed as a redundant backup power source in critical applications.

Physical analogue connectivity on the Anubis comprises two balanced mic/line inputs on combi XLRs at the rear, and two instrument/balanced line TRS sockets at the front. In addition, there are four balanced (and DC-coupled) line outputs at the rear — two on XLR sockets and two on TRS —plus two independent quarter-inch stereo headphone outputs at the front. Very usefully, these outputs can be reconfigured through the unit's software to provide an additional pair of mono balanced line outputs, if desired, neatly enabling the Anubis to drive a 5.1 monitoring system directly with six balanced line outputs.

A talkback microphone is built in (though it shares line input 4's preamp), and another pair of TRS sockets on the back panel can be employed either for MIDI In/Out or for GPIO functions such as red-light switching, as footswitch inputs for activating talkback, and so on. Other connectivity includes a single locking Ethercon RJ45 socket for the AoIP network — supporting up to 100 metres of Cat5e/Cat6 cable — and a 9‑15 V bayonet-locking coaxial DC power inlet. A small and easy-to-miss on-off button sits alongside this power socket, and there's also a Kensington Lock slot.

Looking at that compact I/O count — and indeed the diminutive dimensions of the control unit itself — you could be excused for thinking the Anubis has a fairly limited capability. In reality, though, this is a remarkably powerful and fully fledged AoIP system controller, as well as a sophisticated audio signal processor and a small — but very high-quality — analogue interface.

The Anubis' back panel squeezes a lot into a small space. Twin headphone outputs and line inputs 3 and 4 are found at the front.The Anubis' back panel squeezes a lot into a small space. Twin headphone outputs and line inputs 3 and 4 are found at the front.

At the heart of the Anubis' hardware is an FPGA-based, ultra-low-latency digital signal processor which provides input signal conditioning (high-pass filtering, polarity inversion and so on) as well as comprehensive signal routing, a mixer that can run up to four 128 x 8 mix engines simultaneously, and other DSP functions. This capability allows the Anubis to control, route, mix and monitor multi-channel content from up to 256 audio channels anywhere on the AoIP network. The round-trip latency (RTL) from analogue in to analogue out can potentially be under 20 samples, and it stays under 30 samples even when the Anubis is connected to a computer.

Functions are all configured and controlled using a colour touchscreen (in 16x9 format on a 800 x 480-pixel TFT LCD) with context-aware displays and menus which are all well structured and easy to follow. In addition, there's a nicely weighted anodised aluminium encoder knob and seven chunky backlit buttons with dedicated functions. These include accessing the home menu, the functions associated with two different sets of monitor speakers and two headphone outputs, as well as talkback functions and muting selected monitoring outputs.

With all that number-crunching going on the Anubis' total power dissipation is around 15W, but the aluminium chassis is used as a heat sink, so the unit gets marginally warm to the touch after it's been running for a while. In extreme conditions a small variable-speed internal fan is activated automatically, but I wasn't aware of it running at all during my testing.

Modular By Software

I mentioned earlier that the Anubis is a developing product, and that's largely because Merging have introduced a concept called 'Modular by Software' whereby the same physical hardware can be configured for completely different functionalities and workflows — called 'Missions' in Merging's vernacular. At the time of writing the only available 'Mission' — installed as the default operating mode — is called '+Monitor' and this enables the Anubis to serve as a very comprehensive and versatile multi-channel monitor controller. When other Missions are made available, the required mode will be selectable during the boot-up sequence.

The second planned 'Mission' — expected soon — is the '+Music' mode and, as the name implies, this will be focused on music recording applications. Apparently it will provide on-screen features like input faders and pan controls, low-latency cue monitoring feeds, various relevant signal processing effects, and so forth. Other Missions with alternative capabilities, applications, and workflows are apparently in the planning stages for later release.

Currently, though, the Anubis serves purely as a monitor controller, providing local balanced analogue line-level connections for a stereo monitoring system complete with an alternative speaker set, both having independent mono, dim, mute, level control, bass management, and source selection and mixing facilities. Maximum, reference and dim levels are customisable, and the two independent high-powered headphone outputs each have adjustable cross-feed options to reduce that inside-the-head effect.

Alternatively, the Anubis can be configured to use all its physical outputs to drive a single 5.1 monitoring system, as I mentioned above, and it can even control a local 7.1 monitoring setup if necessary. However, the Anubis really comes into its own in controlling large multi-channel monitoring systems: up to eight separate monitoring systems with up to 32 channels each can be managed! The lack of physical I/O isn't an issue, as the Anubis can control the appropriate outputs on multi-channel I/O units — such as the Horus or Hapi interfaces — connected to the Ravenna network. This makes it possible to control 22.2 theatre sound systems and Dolby Atmos installations among others; there are nearly 60 different format options listed! Impressively, the Anubis can also generate down-mixes from any format to any other, from 30.2 channels all the way down to mono, via 22.2, Auro13.1, Dolby 7.1.4, and many more. It is also planned that it will be able to handle Ambisonic arrays from first to seventh order, with full decoding to suit the active monitor speaker set format.

Overall, the Anubis is as close to being technically perfect as you're likely to find anywhere, and that's seriously impressive given the relatively modest price.

From the point of view of specifications and technology, the Anubis is as impressive as we've come to expect from Merging. The preamps and converters are configured in a novel dual, 32-bit architecture which is claimed to provide a dynamic range of over 136dB (A-weighted). The D-A converters enjoy user-selectable filtering options, with corresponding variations to the sound character and latency. The fastest option, and the most similar to standard converters, is the 'sharp' setting at around five samples. However, the 'slow' option is the default, with a slightly gentler slope and a latency of almost 10 samples, while the more computationally intense theoretical 'brickwall' and 'apodizing' options are around 35 samples. If that last term is unfamiliar, the apodizing filter removes the time-domain pre- and post-ringing generated by linear-phase converter filters used anywhere throughout the entire recording/playback chain!

The 'dual path' preamp feature provides two independent input signal paths for each input source, so two preamps and two A-Ds with different (high and low) gain structures. The outputs of these two A-Ds are combined in DSP to maximise headroom and minimise the noise floor, thus achieving an overall dynamic range in excess of 136dB. Each input source is then duplicated within the DSP to feed two output destinations, each path having its own set of controls (gain, filter, polarity, mute and so on), so that one path could feed monitors and the other FOH, for example, with total independence. The operational gain controls are all DSP-based, providing a click-less range of 66dB in 0.5 (or even 0.1dB) increments, scaled as 0 to +66dB for mics, -24 to +42dB for line inputs and -18 to +48dB for instrument inputs.

When it comes to maximum levels the line input can accept +24dBu, as can the mic input with the pad engaged (it's +12dBu without), while the instrument input can handle up to +18dBu. The maximum line output level is also +24dBu, or +17dBu from the headphone amps. The mic preamp's EIN figure is a near-perfect -128dBu for a 150Ω source, the inter-channel crosstalk at 1kHz)is almost unmeasurable, and phase deviation is below two degrees across the entire 10Hz-100kHz bandwidth. Overall, the Anubis is as close to being technically perfect as you're likely to find anywhere, and that's seriously impressive given its relatively modest price.

System Configuration

As I don't operate a full Ravenna network in my own studio, I set up the Anubis just to communicate directly with my music PC on its own gigabit network, and installed the appropriate Merging ASIO driver along with Merging's AoIP network management tool, called ANEMAN. Once the PC had rebooted I simply had to reconfigure my DAW to use the Merging ASIO driver and set up the appropriate channel mapping. Using the ANEMAN program I was then able to 'connect' my PC to the Anubis across the Ravenna network and set up the required signal cross-points between the relevant sources and destinations. I found everything reasonably logical and easy to navigate, but it is clearly an immensely powerful system in the context of a full Ravenna network. Thankfully, previously established network connections are remembered when the system is fired up, and routing configurations can be saved as presets for easy recall, so after the initial setup, all is plain sailing.

The ANEMAN (Audio Network MANager) configuration screen.The ANEMAN (Audio Network MANager) configuration screen.

The Anubis takes about a minute to boot up and become operational, but once running it operates much like any other monitor controller, except that this one is immensely configurable and can handle a lot of channels! I simply don't have space here to go into every option, but suffice to say that it did everything I could think of... once I'd found out how to configure the requiredoption!

A small status bar is shown across the top of the screen with flags for phantom power, overload, active talkback, GPIO and MIDI data, master or slave clock status on the Ravenna network, sample rate, and status/error log messages. A Settings page accesses all the configuration options and presets — and there are a lot of them — but it is all fairly self-explanatory and I rarely needed to refer to the manual. They cover things like network and clocking parameters, converter filtering options, metering preferences, talkback destinations, GPIO and MIDI options, monitor speaker formats, bass management, and so forth. So, so many options...

The preamp menu screen sets up facilities like input source, phantom power, pad, high-pass filter, polarity, stereo link, gain, input mute (to allow the broadcast function of a 'cough key'), and so on. It starts showing the combi XLR inputs, but a swiping action scrolls to the line/instrument and talkback mic inputs. The sound quality of the preamps is beyond reproach: ultra-quiet, totally neutral and transparent, and with massive headroom. What's not to like?

Call up the monitor mode and you'll see three separate control screens — monitor, source and meters pages — which cycle with each press of the Merging Home button. There's perhaps a bit more screen-tapping and cycling to access some functions in the Anubis than there might be in more traditional professional monitor controllers, but I think that's to be expected in such a compact device. The plain fact is that there are far more facilities available than in most controllers, and they are certainly more configurable to suit a much wider range of different applications and preferences.


In short, the Anubis is a small but seriously impressive piece of audio hardware that can be configured surprisingly easily to control and perform all manner of sophisticated audio tasks either locally or remotely across a Ravenna AoIP network. It can be used as a simple but very high-quality DAW interface when connected directly to a computer — as I did in this review — but it is when connected to a large scale Ravenna network when the enormous power of this diminutive interface really shines brightly. I look forward to seeing what Merging can achieve with this ingenious and elegant platform in the future, as more 'Missions' are developed. In the meantime, the Anubis is a very impressive system controller for Ravenna networks and is well worth investigating by anyone needing to control large monitoring systems or work with very high channel counts in whatever capacity — studio, live sound, broadcast, or theatre!


  • Superb sound quality and technical performance throughout.
  • Preamps boast phenomenal dynamic range capability.
  • Ability to control and process a massive number of channels over a Ravenna network.
  • Totally configurable hardware platform with alternative 'Missions'.
  • Well-designed touchscreen control paradigms, supplemented with critical physical buttons.
  • Astonishing number of monitor speaker formats comprehensively catered for.


  • It could take a while to become completely conversant with all the options and facilities.


A surprisingly small but astonishingly powerful Ravenna network system controller and interface, with the added ability to link directly to a computer DAW, if necessary. The Anubis also features stunningly impressive preamps which offer over 136dB dynamic range, thanks to a dual-path A-D architecture.


Anubis Pro £1672, Anubis Premium £2179. Prices include VAT.

Anubis Pro $1799, Anubis Premium £2299.

Published May 2020