Audio Gear Obsession SUMMINGFACILITY + DYNAMICENGINE Review

Making the Modular Synthesizer the Center of Your Studio

Ryan Gaston · 05/22/23

The original purpose of the analog modular synthesizer was simple: it was meant to be the central hub for an experimental music studio.

At a time when creative studios were primarily made of disparate equipment from many manufacturers—recording equipment, test equipment, and wartime surplus parts—the modular synthesizer was designed to offer experimental musicians a more complete, cohesive, and holistic means of honing their studio art. The modular synthesizer could generate sound; it could process external sounds; it could be used to impose shape and form on external audio materials; it could even act as a mixing console, acting as a means of combining signals and routing audio to/from external processors and recording equipment. It was a peculiar hybrid device: part instrument, part composition tool, part recording facility.

In the modern day, though, the modular synthesizer has evolved to fill a somewhat different purpose. Now, when music production and mixing is so highly dependent on computers and digital audio workstations, the modern modular synthesizer is more commonly seen purely as an instrument. Its role is to make sound, while the computer or other specialized outboard equipment is designed to record, process, mix, and finalize audio projects. But...what if it didn't have to be that way? Could it be possible to construct a studio workflow with the modular synthesizer at the very center—acting as instrument, mixing tool, recording aid, and more?

The answer, of course, is yes. And in fact, while most Eurorack manufacturers seem to focus primarily on creating tools for sound generation, sound design, and live performance, there are a small handful of makers who focus primarily on creating Eurorack-format audio processing tools suitable for use in professional recording studios. Perhaps none does so quite as loudly and proudly as Audio Gear Obsession, an Italian modular designer who strives to bring pro-level build and audio quality to the Eurorack format.

Audio Gear Obsession's no-compromises approach to sound and build quality means that their modules offer the same level of performance you'd find in professional 19" outboard gear, 500 Series modules, or in pro recording consoles...but it all conforms to Eurorack standards, and can be installed in any Eurorack modular synthesizer. They use only the highest quality parts, and design their modules so that they're fully compatible with both Eurorack level and line level signals...so they can easily be used to integrate your modular system at any point in your production signal chain. Use them to glue the sound of your modular system in real time, or use them as an analog summing/mastering process for your final DAW mixdown—it's all fair game!

The point is this: while you can certainly use their modules in any musical context—including live performance—they shine in the studio, providing studio-grade processing and mixdown capabilities. Combine that with the sheer flexibility and power of the Eurorack format, and these modules have the capacity to form the center of a truly creative and unique production workflow. That thought in mind, let's take a look at both of Audio Gear Obsession's current offerings in detail, discussing their features and their strengths as we go. We'll first look at the SUMMINGFACILITY, a six-channel summing mixer; we'll then dive into the DYNAMICENGINE, a dual mono compressor.

First things first, though: from now through May 30th 2023, we're currently teaming up with Audio Gear Obsession to give away a DYNAMICENGINE and SUMMINGFACILITY—so go to our contests page for your chance to win! But for now, let's dive in and see what makes them both so special.

SUMMINGFACILITY: Studio-Grade Eurorack Summing Mixer

Audio Gear Obsession's first offering, SUMMINGFACILITY, is a six-channel stereo mixer designed to act as the ultimate end-of-chain summing station for your Eurorack modular system. Offering an extensive feature set given its relatively compact size, this module is capable of more than it might initially seem—from simple mixdowns to complex signal routing, integration of external signals, and more. One of the key points worth noting is that it's designed with an astonishing 22Vpp of headroom—simply put, that is a ton of dynamic range. It has negligibly low self-noise, and each of its channels can offer up to a 12dB boost; so, in addition to acting as a great end-of-chain mixer for your modular signals, it can also be easily used with external balanced line-level sources, bringing them up to a range where they can easily play along with your modular-level signals.

SUMMINGFACILITY is comprised of six identical mixing channels and an auxiliary send/return section. You'll notice that the controls more or less mirror what you'd expect to find on a console or summing mixer, so let's look at each of the individual channels to get a sense of how it can be used.

Each channel offers a 3.5mm signal input, channel gain controls, auxiliary send level controls, a pan control, and channel mute switches. The channel controls are arranged more or less how they would appear on a typical channel strip. Each channel's gain setting is controlled via a dual concentric potentiometer, one acting as a coarse level control and the other offering up to 12dB of additional boost. Again, this means that you can mix together both modular and line-level sources without issue. Each channel has access to the two Aux Busses, again, with send level controlled via a dual concentric potentiometer. Channel panning is controlled via a simple potentiometer at the bottom of each channel. Additionally, each channel has two mute switches: one which disables the connection to the left and right main outputs, and one which disables the channel's access to the A and B sends. More on this in a moment.

Each of the two busses features a mono send and return, with per-bus control of the send and return levels (again, via dual concentric potentiometers). As with the channel gain controls, the return can impart a significant boost. All of this means that the busses are great for use both with modular effects and with external line-level signal processors—it'll handle each with ease. Much like the main input channels, each of the return channels has a mute switch and pan control.

The busses offer an uncommon level of flexibility when compared to most other Eurorack mixer modules (which often don't include effect send/return busses at all). Each bus having a dedicated pan control, return level controls, and the ability to remove it from the main mix entirely means that you can do quite a large number of utilitarian and peculiar/non-standard things. You could do mono send, stereo return by using both busses; you could use SUMMINGFACILITY as a quadraphonic mixer; you could use SUMMINGFACILITY to create separate main mix and cue mixes; the choice is yours.

Functionality aside, it's well worth re-stating just how hi-fi SUMMINGFACILITY is compared to most alternatives. It uses modern op-amps designed for high-quality audio performance; it uses WIMA and Panasonic capacitors; it uses 0.5% tolerance thin film resistors, a four-layer PCB to reduce risk of EMI/EMC issues—the list goes on. Truly, SUMMINGFACILITY takes design standards and build concepts from high-quality mixing and mastering gear, and adapts them for use with Eurorack modular synthesizers. Simply put, if your studio has a Eurorack system at its core, SUMMINGFACILITY is a no-nonsense, no-compromises way to ensure that signals get in and out as cleanly as possible, and that your mixes are transparent, punchy, detailed, and cohesive—no matter how busy they might be. It is truly one of the highest-quality mixing options available in Eurorack altogether.

DYNAMICENGINE: Complete Control of Compression and More

Next, let's look more closely at DYNAMICENGINE—Audio Gear Obsession's take on dynamics processing concepts. DYNAMICENGINE is a dual mono compressor with a stereo linking option—and it's designed with the same rigorous design goals in mind as was its sibling SUMMINGFACILITY. So, what you get is an uncommonly flexible dynamic processing solution...one that is every bit as capable of subtle bus compression as it is drastic dynamic alterations to individual sounds.

Again, as with SUMMINGFACILITY, DYNAMICENGINE is designed to work with both modular and line level signals, and offers balanced I/O for ease of integration into your studio setup. It has extremely low self-noise, due in part to its use of a proprietary triple-VCA compression scheme based on THAT Corp. VCAs. Once again, you get only the highest-quality parts, a four-layer PCB, and an impeccable build overall—so it's just going to sound great, virtually no matter what you do with it. That said, let's take a look at the controls.

DYNAMICENGINE features a dedicated 3.5mm input, output, and sidechain input for each of its channels. Additionally, it offers all the controls you'd expect on a professional compressor, and then some. Looking at a single channel, you get controls for incoming signal gain and compression threshold on a dual concentric potentiometer; similarly, it offers attack and release time controls on a dual concentric potentiometer. There are dedicated controls for compression ratio (continuously variable from 1:1 to hard limiting), make up gain (-10dB to +20dB), and, quite conveniently, wet/dry mix—allowing for simple parallel compression techniques, among other things. You also get a switch to switch between hard or softer knee settings, as well as a per-channel bypass switch.

Each channel also offers an option for external sidechaining, great for creating responsive, dynamically evolving mixes. Each channel has a dedicated sidechain input, with gain variable from -10dB to +12dB. You also have access to a switchable sidechain lowpass filter, with cutoff frequency variable from 20Hz to 235Hz—excellent for dialing in ducking response based on low-frequency signals like bass tones or kick drum sounds.

DYNAMICENGINE is comprised of two identical channels, though a central stereo link switch makes it possible to dial in stereo compression by using one set of controls to govern the entire module's behavior. Conveniently, you get level indication LEDs for the inputs, outputs, and sidechain inputs, as well as a bright, clear gain reduction LED display front and center. This makes it easy to confirm your settings, ensuring that you're always dialing in just the right amount of squish.

With such a wide range on all parameters, DYNAMICENGINE can handle everything from subtle squeeze to pumping sidechained textures, brutally squashed/in-your-face mixes, brick wall limiting, and much, much more. If you're seeking a way to keep your mixes feeling full, punchy, present, and clear—this module shouldn't be overlooked.

Making the Modular the Center of Your Studio

Now, not everyone needs their Eurorack system to have studio-quality mixing and compression onboard. But, the more prevalent that Eurorack modular synthesis has become, the more common it is to see Eurorack systems as prominent fixtures in serious, professional production contexts. It's not uncommon to go into a pro studio and find a substantial Eurorack system. More and more commonly, these systems are used as part of the mixing process itself—either as an instrument, or for processing prerecorded stems or groups. The consistently creative angles these instruments offer for sound designers and mixing engineers mean that they're constantly finding more use in professional circles.

Audio Gear Obsession is leading the charge in ensuring that these tremendously creative tools can seamlessly integrate into these contexts. But more than that—they're also bringing the performance and quality of true professional audio equipment to a context more commonly adopted by independent musicians and producers. That means that you have the opportunity to get console-quality summing and compression without needing a console, and without needing to buy into the API 500 Series format.

Moreover, despite SUMMINGFACILITY and DYNAMICENGINE being Eurorack format modules, they're designed to be used with virtually anything you might have in your arsenal. You could use them to sum and process your desktop drum machines or keyboard synths; you could use them as a final summing mixer/mastering chain for groups in your DAW; or, you could simply use them to get high-quality, clean, clear, 3D-sounding mixes straight out of your modular system. Simply put, if you're in a situation where high-quality mixing or compression are paramount in your modular system, these are some of the best options available.

And of course, we eagerly await whatever is next for Audio Gear Obsession. Remember—from now through May 30th 2023, we're currently teaming up with Audio Gear Obsession to give away a DYNAMICENGINE and SUMMINGFACILITY—so go to our contests page for your chance to win!