Merging Technologies Sphynx Modular Digital Interface

It gladdens me to discover a manufacturer who makes a product that perfectly fits the way I work. Merging Technologies' Sphynx Modular Digital Interface is such a product. I've been separating the analog source (by hundreds of feet of glass fiber-optic cable) from my digital recording equipment for my location productions since 1988 and am always searching for products to make that process more efficient.
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It gladdens me to discover a manufacturer who makes a product that perfectly fits the way I work. Merging Technologies' Sphynx Modular Digital Interface is such a product. I've been separating the analog source (by hundreds of feet of glass fiber-optic cable) from my digital recording equipment for my location productions since 1988 and am always searching for products to make that process more efficient. Ten years ago, when I sent only stereo digital data down that skinny cable, it was relatively easy to separate the ADC from the DAC.
Product PointsApplications: Recording studio; high end project studios

Key Features: Modular construction; variety of inputs and outputs: analog at 32/44.1/48 or 64/88.2/96 kHz, AES/EBU, and ODI

Price: $3,995 to $5,995 depending on configuration

Contact: Merging Technologies at 847-272-0500


+ Very clean sound

+ Flexible I/O possibilities

+ Easy upgrade path


- Requires DAW software for signal routing

The Score: For the best-sounding multichannel high sample rate interface for your workstation, recorder or digital console, look no further.
I've been recording in 24-bit multichannel format for several years now, however, and have been using various jury-rigged solutions to transmit and receive multichannel digital data over long distances. In 1998, for example, I arrived at what I thought at the time would be the final solution - sending eight channels of bit-split 44.1-kHz/24-bit data from two Fiber DX AMBUS cards in my Apogee AD-8000 to two custom glass-to-plastic fiber-optic converter boxes, through two Apogee FC8 ADAT-to-TDIF converters, into two DTRS recorders.

I needed to do the same for my 96 kHz recordings. Using four Apogee PSX-100s (and doubling the number of boxes and recorded listed above) is a bit unwieldy. Until last fall's AES convention, I believed there was no multichannel high sample rate interface similar in function to the 44.1/48 kHz Apogee AD-8000.

Enter Merging Technologies. Although rather unknown in the U.S., this Swiss company is well-known in Europe as an OEM manufacturer of boards and converters for various high-end digital audio and video systems.

At AES in New York City last September, Mark Lindahl, president of Sonorus, introduced me to Merging Technologies' president, Claude Cellier, and told me that the company would be manufacturing the Sphynx box as Sonorus' new Modular/8 interface. Thus, for the purpose of this review, please consider the Sphynx and Sonorus' Modular/8 to be functionally and electronically identical.


Although comparisons with the Apogee AD-8000 will be inevitable, the Sphynx is really a completely different kind of box, both in concept and in execution. It is a two-rack-space unit, whose front panel contains 37 tiny red or yellow LEDs, three small pushbuttons, a single headphone jack (with its associated volume control), and a power switch. The rear panel looks slightly more conventional, with 17 XLR connectors for analog and digital I/O, three BNCs for word clock or video sync I/O, a pair of S/PDIF jacks, four TOSlink ADAT ODI connectors, and a multivoltage IEC power jack. Inside the box are card slots for four small input and four output module cards, the unit's CPU motherboard and its power supply. If this sounds more like a PC than a piece of audio equipment, you're starting to get the picture.

The Sphynx's unconventional design is best illustrated by describing the three configurations in which it is most commonly sold. For the base system, four of the eight module slots are filled with two stereo analog input and two stereo analog output cards and four are left empty. All configurations share the motherboard's built-in double dual ADAT-type ODI ports, S/PDIF I/O and the stereo monitoring DAC, headphone amplifier and associated track pair monitor selector. The configurations differ only in the type and number of I/O modules installed.

The base configuration allows the user to record and play back eight channels of 32/44.1/48 kHz 24-bit data to a 24-bit capable recording system whose interface with the external world is via lightpipe connectors.

The full system configuration Sphynx model fills up the other four module slots with pairs of AES/EBU input and output cards.

Another configuration upgrade would be to substitute 96 kHz-capable I/O cards for the for previous two models' 48-kHz modules. This is what I used on an organ music recording session in Denver last October, except I brought two Sphynx boxes with me! This luxury let me put the input and AES/EBU output cards in the transmitting Sphynx, and the AES/EBU input and analog output modules in the receiving Sphynx. At that four-track session, I had four empty slots in each Sphynx. I have since filled those empty slots and can now send and receive eight channels of 96 kHz. Of course, Merging has already announced the availability of 192 kHz analog I/O cards, as well as new AES/EBU modules, which perform both input and output functions; upgrading is simply done by swapping modules.

In use

Upon powering up, the Sphynx provides a light show from its 37 mostly red LEDs. The manual explains how to read the code to check the CPU and EPROM revs and to verify proper operation of the various modules. Several seconds later (longer for the 96 kHz ADC cards), the unit begins normal operation. One then simply selects the sync source (internal, ODI, AES/EBU, WC, word clock, video or S/PDIF), chooses a sample rate - if running on internal clock - and applies analog input. There is a built-in calibration position of +4 dBu and a set of variable pots available through the top cover - switchable in software by a few button presses on the front panel. The sample rate pushbutton cycles between 32, 44.1 and 48 kHz and multipliers of x1, x2 and x4 (which is not yet available); automatic detection from digital inputs is also possible within each sample rate group.

If all settings have been made properly, signal activity is visible on the bottom row of eight yellow level LEDs. The top row of red indicators indicates overs on each channel. This metering scheme appears somewhat limited until one realizes that this box was designed for use with DAW software, such as Merging Technologies' own Pyramix or Logic or Cubase. The LEDs simply indicate signal presence in the input modules.

If the Sphynx is set for standalone mode, this signal is then output by the corresponding channel(s) of any installed output modules and simultaneously from the multichannel ODI connectors. In normal mode, it is output only via ODI; one needs DAW software to route signal to the output modules.

My first Sphynx contained a revision 1.4 EEPROM. Three months later I'm up to 1.6, which incorporates many improvements including, most importantly, a software settings menu in software through which the user can set many important parameters just by pushing one or two of those three front panel pushbuttons. These include analog I/O level, AES/EBU input SRC toggle, dithering down to 20, 18 or 16 bits, selection of high-speed or double-wide AES/EBU I/O protocols, standalone mode toggle (instead of computer control), and word clock I/O choice in "X2" sample rate mode - fs/2 or fs/1.

My first listening test took place in the Denver recording session in which I recorded music performed by two organists on one organ at the Cathedral of the Immaculate Conception.

I was able to directly A/B three different four-channel feeds. Digital and analog data flowed back and forth between the front-end equipment up in the nave and the monitoring and recording gear in my makeshift control room two floors below it. Those three feeds were: straight analog, a double Apogee PSX-100/DTRS tape setup and the Sphynx/HD system. Monitoring was through both Dynaudio BM6As and Stax SRX Mk. III Pro electrostatic headphones.

What differences I heard! In comparison to the undigitized analog feed, the Apogee had that typical warm, euphonic "Apogee sound." At 88.2 kHz, it was very sweet on top, and nice and warm in the low end - a bit fatter than the analog source, in fact. The Sphynx, on the other hand, produced what I call the British sound - one characterized by extreme clarity and a naturally open quality. The Sphynx output was closer in sound to the analog than was the Apogee; I judged it more successful at delineating the subtle harmonic interplay possible with 20 fingers and four feet on a monstrous pipe organ.

Back home at Studio Dufay I tested the Sphynx on many types of music. Each time I listened to something new through it, I smiled! Here was a converter set I could live with for a long time - a worthy yang to the Apogee's yin. Every detail came through clearly. I consistently came to the same conclusions I had made in Denver.

The highs sounded best at 96 kHz, as I have discovered with other high sample rate converters. At 88.2 kHz, they were already a bit dimmed. At the lower sample rates, the sound was very similar to that at the higher rates but possessed a certain constriction in the highs and mids, which was not present at 88.2 or 96 kHz. At 96 kHz, the highs were crystal clear, the midrange very present and the lows punched strongly.

I do not make my sonic assessment of the Sphynx lightly. The reason I own and use both Apogee and Prism converters for my 44.1 kHz recordings is that I need both kinds of sound for analog to digital conversion of different types of music. The Sphynx is the first high sample rate converter I have heard that I would put in the same sonic category as my Prism AD-1.


Recording multitrack at 96 kHz has proved far more problematic than I had previously believed. At least with Merging Technologies' Sphynx, I can verify that the conversion and transmission issues have been successfully accomplished.

I'm looking forward to trying Merging Technologies' Pyramix software with its Mykerinos sound card - a PC solution! I'm told I'll be able to record all eight 96 kHz tracks from the Sphynx with no sweat, as well as do lots of DSP. There's certainly an advantage in having a single manufacturer supply both software and hardware.

Merging Technologies has obviously taken the lead in high sample rate multitrack recording. With superior products like its Sphynx now available in this country, the company certainly won't remain unknown for very long!