SSL SIGMA ANALOGUE SUMMING DEVICE
What’s the plus side of having an analogue summing mixer? SSL reckons the answer lies partly in the digital realm.
Review: Greg Walker
Back in Issue 106 I reviewed the Phoenix Audio Nicerizer Junior and was impressed by what a simple, well conceived analogue mixdown path could do for a digital mix. Fast forward six months and another 2RU summing device has landed on my desktop, this time created by analogue mixing gurus Solid State Logic. The SSL Sigma is a very different beast to the Nicerizer however, coming with a feature list as long as your arm and the promise of becoming the nexus of your studio, via its digitally-controlled analogue systems and generous interfacing options. While I was pulling the Sigma out of its modest box I had to wonder how much further SSL can shrink down its large format console technology before the baby gets thrown out with the bathwater. I was very curious to hear whether the Sigma could make my mixes more than the sum of their parts, and whether it could impart that oh-so-desirable SSL sound along the way.
OUT OF THE ETHER
There are a few basic concepts to get your head around with the Sigma. One is that it uses the first 16 channels inside your DAW session to control the analogue input gain levels going into the summing circuitry. It does this via an ethernet connection with your computer using either HUI, MCU or MIDI protocols. Moving your DAW faders you can control and automate analogue input gain while not letting go of your mouse or taking your eyes off the screen. The second major concept at play here is that detailed control of all Sigma’s functions come via a series of tabs in its web browser interface. Individual inputs are selected for mono or stereo channels, assigned to mix buses, panned, soloed or cut; to name but a few of the many functions that are controlled in this way. The Sigma can also be networked with most smart devices via a router, and future software revisions should allow full control from iPads and other surfaces. The front panel rotary encoder and user assignable push buttons allow a modicum of control over source monitoring and output gains but all the nitty gritty stuff can only be accessed via the web browser software and an internet connection.
To many of us versed in the old hands-on ways this may seem quite odd. You don’t need to login to a website to adjust the routing scheme, panning, etc., on most analogue equipment. Nevertheless SSL clearly sees advantages to this way of working — one big benefit being that the Sigma can be tucked away in a rack tower installation, where the operator can control all facets of the summing process without being physically close to the unit. Another benefit is in keeping the front panel very streamlined and informative using a variety of generous backlit LED displays. There is, of course, a large cost saved by not fitting the unit with large numbers of knobs and buttons. The asking price of the Sigma lies within the realms of possibility for the well-heeled home studio or small pro studio owner, while offering a good deal more than most straight-up analogue summing devices on the market.
The Sigma offers 16 input channels selectable between mono and stereo as well as direct outs feeding two independent mix buses (Mix A and Mix B) that can also be fed into one another for mix bus parallel processing. There are mix bus inserts, external source inputs and a well-endowed monitoring, headphone and talkback control centre. On the front panel are two customisable user buttons beneath a rotary encoder that selects between the various mix, monitor and headphone output levels. There’s also a mini jack plug for iPhone and laptop input and a 1/4-inch headphone socket. A ‘MIDI learn’ function allows further customising of operations via external MIDI devices and there’s a footswitch socket around the back that can be assigned to various functions but is nominally set up for talkback on/off switching.
It’s clear that SSL wants the Sigma to take over as the hub of your mixing workflow and be its beating analogue heart. In order to do this, a swarm of compact D-sub connectors on the rear panel covers the 32 channels of inputs, direct outs, mix bus inserts, talkback and even some miscellaneous sends and returns thrown in. In order to properly unleash the power of the Sigma and interface it with even a modicum of outboard gear, a comprehensive patch bay set up will definitely be required.
Two sets of monitor outputs and the Mix A output are on dedicated stereo XLR outputs, and there’s an ethernet port and a USB port for factory diagnostics. The only thing letting down the general vibe of supreme compact 21st Century English Analogue Cool is the +12V DC wall wart power supply — unfortunate but true! SSL is quick to point out that the Sigma is built using the same SuperAnalogue circuitry that graces their Duality and AWS consoles and the popular small-format X-Desk. With a price tag well above $5k we’re talking a pretty big outlay here, so the Sigma needs to be judged with the spotlight on an eye for functionality and ease of use as well as a careful ear for sonic performance.
GETTING A GRIP
I’ve got to say my first day with the Sigma was one of the most frustrating I’ve had with a new piece of audio kit. Not that this was entirely SSL’s fault but nor was it all mine… bear with me. My studio is an internet-free zone and nestles in a mobile coverage black hole in regional Victoria. When I have bands here we have super productive days and we focus on music without any interruptions (there’s phone reception up the hill and internet in the house for those that really can’t hold on). I also do a lot of TV soundtrack work and often have months of relentless weekly deadlines where technological issues and hold-ups are strictly off limits. When I really need to upgrade my software or register something new I put my iMac under my arm and go into the house, otherwise my work computer does not stray near anything resembling the internet. I rarely have computer hassles or new software-related bugs and so the days pass happily by. The Sigma was not conceived for people like me!
Fortunately I keep my setup pretty portable as I often do location recording, and it was no big deal to make a temporary camp in a spare room in the house with Wi-Fi reception. Initially I assumed I would be quickly uploading some software and be off and summing within the hour. As it turned out there were quite a few curve balls to negotiate; including registering serial numbers, configuring internet protocol versions, updating the Sigma software while checking OS compatibility, as well as reconfiguring the HUI ports in my Pro Tools setup (turns out you need 40 of them, even though you will most likely only use two!); all with their requisite reboots and ‘handshakes’.
After about four hours of this I still wasn’t seeing full integration between my computer, Pro Tools and the Sigma and I kept coming back to the same dead end. After multiple read throughs of the user manual and a vain search for aid from various online forums, I finally discovered a small note in the manual about switching off Wi-Fi during reboot after loading the software from the website. Of course the software that needs you to be online to operate the unit needs you to be offline to install it! Finally I was in and able to access the Sigma’s nether regions via the (by now much cursed) web browser but it was far from a smooth process.
LOCK & LOAD
Once you negotiate the twists and turns of configuring your Sigma software (to the supplied Pro Tools template in my case, but all major DAWs are catered for) the software/hardware browser interface is quite simple to use. There are separate pages labelled Master, Channels and Settings, as well as additional tabs for saving and loading settings into the hardware memory. The Master page takes care of metering assignment, mix bus insert selection, monitor and headphone routing as well as setups for Dim, MIDI learn and the user assignable button settings. The Channel page takes care of mix routing, stereo/mono switching, and solo, cut and panning for each individual channel, while a row of global commands down the bottom of the page allows for quick resetting of all 16 channels’ parameters. The Settings page is where you select your choice of DAW, assign MIDI ports, set up your IP network as well as selecting metering scales, SIP or AFL solo mode, and OK software updates.
The Pro Tools template gave me a basic setup which I then tweaked to my preferred way of working. I chose to output the audio from my converters in stereo pairs so I kept all the channels in stereo mode rather than switching them to mono and engaging the browser-controlled panning. Hitting the Save button in the browser locked these settings into the hardware’s memory for ongoing use. Selecting Mix A as my go-to bus brought the master meters to life and I ran the Mix A output back into a stereo channel in my DAW. With the Sigma talking to Pro Tools, the first 16 channels of any mix will be highlighted to signal the implementation of HUI control. So it’s important to create 16 blank channels at the top of any mix to avoid double dipping when adjusting levels. Once this is done it is undeniably nifty to be be able to raise and lower the analogue input levels of an entire mix with one grouped set of faders or explore some interesting individual channel mix automation techniques. For instance, with an outboard compressor patched into your vocal channel you could automate the DAW’s output to hit the compression harder in a chorus and then manage the post-compression gain settings via the corresponding Sigma input channel.
Controlling output levels for the main mix, headphones and monitoring was very easy via the rotary encoder or Master web tab, while accessing features like mono fold-down and monitor switching through the user assignable buttons made for an easy, intuitive mix assessment process. Full marks to SSL for the bright and informative front panel displays which keep things clear when navigating through the various options, as do the various controls in the web browser. Once up and running the Sigma feels like a classy piece of kit, providing all the requisite tools to be the control centre of your studio and taking up very little space while doing so.
So how’s it sound? You can be the judge yourself by going to the AT website and checking out the samples of a couple of different mixes I ran through the Sigma’s summing chain. For comparison I’ve included straight digital mixes as well as mixes summed through the Phoenix Audio Nicerizer Junior at low and high gain levels (at the latter setting that unit starts to introduce some noticeable transformer saturation and compression). There’s no mix bus compression on any of these samples and all the summed mixes were recorded back into Pro Tools using a Universal Audio Apollo interface.
The Sigma mixes do not exhibit overt harmonic saturation but that’s not really this unit’s game. What it excels at is high headroom, wide sound-stage sonics with excellent depth and clarity. For mine the SSL mixes sound the most refined and ‘expensive’ (which indeed they are). It’s certainly not chalk and cheese but the top end is particularly well defined and airy compared to the slightly more grainy, midrange-orientated Nicerizer and the more clinical, in-your-face straight digital sound.
The SSL flavour is definitely there, not as emphatically as it would be through a 96-channel K series console bursting with analogue EQ and compression, but nevertheless it is present. The subtle enrichment of the top end, the solid, cohesive low end and the revealing detail in things like reverb tails are hallmarks of that sound and it’s the reason SSL’s other more budget-orientated offerings such as the Matrix and X-Desk have such a solid fan base.
Workflow will be a decisive factor in determining whether the Sigma is right for your setup. If you like to get your hands on real faders and push a mix around then look elsewhere. If you don’t like dialling up web browsers to change panning setups in your summing mix ditto. If, however, you’re looking for outstanding sonics with a minimal analogue footprint and need 32 channels of pro-level summing with extensive I/O options to interface with your outboard collection, your number has just come up.
The Sigma won’t suit everyone but it shines at everything it sets out to do and significantly raises the stakes in the summing game with a powerful list of add-ons. The SSL sound is alive and kicking in the 21st century and more accessible than ever. That’s something to be grateful for.