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Mixer & USB Audio Interface By Sam Inglis
Published January 2022

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With the SiX, SSL shrank the large-format console. Now it’s grown again!

In the 1980s, everyone aspired to mix on a Solid State Logic console. With cutting‑edge computerised automation, flexible routing, EQ and dynamics on every channel, and the famous SSL bus compressor, the E‑series and G‑series desks were the most powerful weapons available to the heavyweight mix engineer.

Few records are mixed on large‑format consoles these days, but there’s still a place for hardware mixers in the modern studio. For tasks such as rapidly setting up cue mixes, integrating outboard equipment into a DAW‑based setup, communicating with musicians, managing levels and monitor control, it’s hard to beat an analogue mixing desk with physical faders, buttons and knobs. The difference is that today, a console is usually an adjunct to a computer‑based recording and mixing setup, rather than an alternative.

SiX Hits

SSL themselves have always moved with the times, and have proved very adept at adapting their technology to modern working practices. At one extreme, their current live sound products are highly advanced, all‑digital affairs. At the other, the Origin is an all‑analogue, large‑format inline console that combines traditional functionality with a host of clever tweaks to make it the ideal front end for a DAW recording system. In between, their AWS and Duality are both analogue mixers and fully featured DAW control surfaces.

They’ve also targeted the mushrooming home and project studio markets, first with products like the X‑Desk, XL‑Desk and Matrix, and more recently with the most affordable SSL mixer to date: the SiX. This half rack‑width console has only six inputs, but incorporates the kind of routing flexibility and master section functionality that are usually associated with much bigger desks. When you consider that the SiX features not only a pair of very high‑spec input channels with preamp, EQ and compression, but also a bus compressor and a powerful monitor controller with talkback, it also represents extremely good value for money. The SiX was reviewed in SOS April 2019 ( by a suitably impressed Hugh Robjohns, who also confirmed its excellent technical performance using his Audio Precision test kit.

Going Large

Although it’s much more versatile than such a small mixer has any right to be, the SiX naturally has its limitations, some of which no doubt have left a few potential buyers thinking “If only it did X…” Most obviously, although it’s designed to work with computer‑based recording setups, it doesn’t have any audio interfacing capability of its own. The SiX’s handling of such things as cue mixing and monitor control is exemplary, but passing signal to and from a computer means pairing it with another device. And, of course, although six inputs is plenty for many small studios, it’s not sufficient for multimiking a drum kit, tracking a full band, or combining a large number of hardware synths.

For these reasons and more, SSL have now introduced a big brother to the SiX. If they’d continued their policy of deriving the name from the channel count, this new model might have ended up being called the TWeLVe, so perhaps sensibly, they’ve opted for BiG SiX.

The new model is BiGGeR in pretty much every conceivable way. At the most basic level, it’s twice the size, spanning a full 19‑inch rack width. It comes with smart and robust plastic end cheeks, but these can be replaced by an optional rackmounting kit. As on the original SiX, the I/O is divided between the front panel and a deeply recessed cavity at the top of the mixer. This is set so far back as to make access a little awkward, but means there should be no plumbing issues when the BiG SiX is rackmounted. It also does a good job of protecting the on/off switch and external PSU connector from accidentally being knocked.

The SiX employs four different connector types: female XLRs for the mic inputs, male XLRs for the main bus outputs, quarter‑inch jacks for most of the other line‑level I/O, and a pair of D‑subs for the insert sends and returns. On the BiG SiX, this roster is streamlined, presumably in response to user feedback. It seems I’m not the only one who dislikes DB25 connectors, as both these and the male XLRs are refreshingly absent. Instead, all line‑level I/O including the main bus outputs, input sends and returns is now on balanced quarter‑inch jacks. I think this is a sensible move, and while quarter‑inch looms will never be as compact as D‑sub ones, they’re a lot more durable in my experience.

Losing the D‑subs has meant saying goodbye to the SiX’s parallel monitor output and to the analogue ‘alternate inputs’ for its two mic/line channels. I suspect the former is little used anyway, and the loss of the latter is massively outweighed by its replacement, which I’ll come to in a moment.

Down with D‑subs: the BiG SiX’s line‑level I/O is all on balanced quarter‑inch jacks. The all‑important USB‑C socket lurks next to the PSU input, bottom left.Down with D‑subs: the BiG SiX’s line‑level I/O is all on balanced quarter‑inch jacks. The all‑important USB‑C socket lurks next to the PSU input, bottom left.

Mixed Doubles

The BiG SiX doubles the SiX’s basic channel count, starting with four mono mic/line channels. These have the same high‑quality mic preamp, one‑knob compressor, long‑throw fader, fully balanced insert point and switched stereo Cue sends as are found on the SiX, but they add quite a bit of additional functionality. Each channel now has a polarity switch (hurrah!), pre/post‑fade switching for the Cue sends is send‑based rather than global and a fixed Mid has been added to the existing high‑ and low‑frequency EQ bands. The channel layout is also more conventional and, to my mind, much more ergonomically friendly, with the EQ and Cue controls now occupying clearly delineated areas. The signal processing order is still fixed, with the EQ feeding into the compressor and then the insert point, but this doesn’t strike me as a huge limitation.

To the right of the mic/line channels, you’ll find four stereo line‑level channels. Once again, these now feature pre/post switches for each Cue send, but bigger news is the addition of a three‑band EQ similar to that featured on the mic input channels. The Bell options for the high and low bands are absent, and there’s still no control over bandwidth or frequency, but this is nevertheless a pretty big addition in my book. It means these channels come into their own not only for combining live sources, but also for processing stems at mixdown.

Small but worthwhile enhancements over the SiX are also apparent in the BiG SiX’s master section. The bus compressor now has a switched auto‑release option, making its action even smoother on most material. New legending does away with the confusing distinction between ‘Cue’ and ‘Foldback’, although the slightly unconventional implementation of talkback takes a bit of getting used to. On most consoles, talkback is activated by a single button, with further routing options determining who gets to hear your dulcet tones. On the BiG SiX, the talkback mic is hard‑wired to the two Cue buses, with separate buttons for each. These don’t offer momentary operation and are rather awkwardly placed in the middle of the master section.

The master section also now boasts a second headphone socket, meaning that many users won’t need to budget for a separate headphone amp. Each can be switched independently to pick up either the main monitor bus or either of the Cue buses, and there’s more than enough level on offer for even the most hard‑of‑hearing drummer.

The interfacing aspect of ‘mixerfaces’ often feels like an afterthought, bolted on to a traditional mixer to permit basic multitrack recording and not much else. That is not an accusation you could level at the BiG SiX.

Built-in USB Interface

The really big news, and the most significant development compared with the SiX, is revealed by a profusion of USB symbols and buttons bearing names such as From USB 1 and USB Out Post Fader. Yes, SSL have taken the hint, and the BiG SiX isn’t purely an analogue mixer. It’s also a USB 2 audio interface, presenting 16 inputs and outputs to a connected Mac or Windows PC. On Mac OS, it’s a class‑compliant device, and there is no driver software to install, nor any control panel utility to get annoyed with.

The interfacing aspect of ‘mixerfaces’ often feels like an afterthought, bolted on to a traditional mixer to permit basic multitrack recording and not much else. That is not an accusation you could level at the BiG SiX. SSL have thought hard about how to integrate USB connectivity in such a way as to enable multiple different working approaches — including, as I’ve already mentioned, hybrid or stem mixing of DAW projects. The first 12 recording inputs to the computer are drawn from the four mono and four stereo input channels. The signal is always taken post‑EQ, compressor and insert point, while the aforementioned USB Out Post Fader button selects whether it should be tapped after the fader too. This is a great option to have. Tapping the signals pre‑fader allows you to set up a monitor mix on the BiG SiX whilst retaining optimal gain structure to the computer, while the contrary option permits riding the fader during recording to control wildly varying levels.

Two buttons in the master section give you the option to assign USB inputs 9/10 and 11/12 separately to the two stereo Cues rather than to stereo channels 3 and 4; if you didn’t need both Cues for monitor mixes, this could be used as a way of recording the talkback input, with its distinctive preset compressor. USB inputs 13/14 and 15/16 are hard‑wired to pick up the BiG SiX’s Bus B Master and main master output respectively, in both cases post‑fader. It’s a shame that these cannot be switched to pick up the four Ext In jacks instead, as that would provide a way of recording four extra line inputs at a pinch. As it is, 12 simultaneous inputs is really the practical limit for recording; conceivably you could add two more by routing only Ext In 1/2 to the master bus and recording that, but you’d lose most of the actual mixing functionality.

Each of the BiG SiX’s input channels can pass either an analogue signal or a USB return from an attached computer.Each of the BiG SiX’s input channels can pass either an analogue signal or a USB return from an attached computer.

As I’ve already mentioned, the SiX’s analogue ‘alternate inputs’ have disappeared along with its D‑sub connectors. In their place is a From USB button on each channel, which allows its signal to be taken from the USB stream rather than from the analogue input. With all these buttons engaged, USB outputs 1‑4 from the computer feed the four mic/line channels and USB outs 5‑12 supply the four stereo channels. The last four USB outs are routed into the BiG SiX’s two stereo Ext In paths, making these the obvious choice for system sound from your Mac or Windows machine.

The BiG SiX inherits its sibling’s eight‑segment LED ladder meters. The topmost red LED lights when the signal reaches +24dBu, and this aligns with the clipping point of the A‑D converter, meaning that if you keep input signals in the green and amber zone you’re unlikely to end up with overs in your computer recordings. Likewise, a 0dBFS output from your DAW will generate a +24dBu analogue signal feeding into the relevant mixer channel. The A‑D and D‑A converters are the same chips used in SSL’s premium live sound consoles, and both offer an A‑weighted dynamic range of 117dB. THD+Noise figures are equally impressive, and sample rates of up to 96kHz are supported with no loss of functionality.

Rapid Turnaround

What this means in practice is that the BiG SiX can be repurposed from a recording ‘front end’ to a stem mixer almost instantly, with no repatching. The potential use cases are innumerable. For example, if you leave mics permanently connected to inputs 1‑4, with outboard patched into the insert points, you then have the option of printing the input signal with EQ and compression. For mixdown processing, you could then treat these four channels as ‘hardware plug‑ins’ in your DAW; or you could stem out your multitrack across the 16 USB outputs that address the BiG SiX, mix live through its master bus with G‑series compressor and optional insert, and then re‑record the output into your DAW. None of these options would require any plugging or unplugging, and if you decided to add a last‑minute overdub, all you’d need to do is press a From USB button. You could even hook up a tape delay and spring reverb to the Cue sends and use them for dub mixing. It’s all beautifully thought out, and triumphantly extends the SiX’s ethos of being more versatile than you’d expect into the digital realm.

I can only really think of one caveat that should be borne in mind. As previously mentioned, the practical limit for simultaneous USB recording is 12 inputs, and it’s a hard limit: USB interfaces typically can’t be cascaded in multiples, and the BiG SiX is no exception. Moreover, if you don’t use the USB interfacing and try to treat the BiG SiX as an analogue front end for another interface, you won’t even get 12 recording inputs from it. There’s no track busing structure such as you’d find on a large‑format console, so the only way to get individual channel outputs in the analogue domain would be to repurpose the insert sends and Cues — which, of course, means that they can’t then be used for their intended purposes. This limitation would be hard to overcome without making the BiG SiX a very different and much more expensive product, but potential buyers should ask themselves whether 12 input channels is really, absolutely, definitely enough for them. In an ideal world, SSL could perhaps have built in eight further channels of emergency digital I/O addressable from ADAT optical ports, for those occasions when having a stereo room mic means you can’t record the hi‑hat.

Special SiX

At the most superficial level, the BiG SiX might appear comparable to much cheaper products from other manufacturers: Tascam’s Model 12, for example, or Soundcraft’s Signature 12 MTK. But even a little investigation will show you that that’s not the case. Far from being expensive for what it offers, SSL’s big‑small mixer actually represents amazing value for money. Other products with apparently similar features are built to a price. Their technical performance is good compared to the budget gear of yesteryear, but you probably wouldn’t want to use them on a high‑stakes classical recording session; and a feature set that looks impressive on paper often turns out to be incapable of adapting to different ways of working.

What distinguishes the BiG SiX is the way that SSL’s heritage of large‑format console experience comes through in almost every aspect of its design. You’re not just getting four reasonably acceptable mic preamps that are usable at a pinch: you’re getting four state‑of‑the‑art input channels that would probably cost thousands if you bought them in rackmounting form. You’re not just getting a couple of adequate headphone amps and a volume control, but a proper master section with genuinely flexible routing and monitor control facilities. You’re getting a device that operates at ‘pro’ signal levels. You’re getting balanced insert points on both the mic channels and the master bus. You’re getting true stereo Cue sends. And, of course, there’s that preset but great‑sounding SSL EQ and compression, all of which can be switched completely out of circuit if you don’t need it. Even if you treated the BiG SiX purely as a way to get hold of four SuperAnalogue input channels, and never used the rest of its features, you’d still be getting a lot for your money. When you consider what else it offers besides, it starts to look like a real bargain.


  • Offers the same superb sound quality and technical excellence as the SiX.
  • Beautifully integrated USB audio interface enables multitrack recording, stem mixing, hybrid mixing and more.
  • New channel strip layout is more ergonomic and has additional features such as polarity switches and pre/post-fade buttons.
  • EQ on stereo channels.
  • Simplified I/O arrangements with everything on jacks or female XLRs.
  • Great value for money.


  • No digital I/O and thus no way to expand a BiG SiX-based system to achieve simultaneous recording of more than 12 inputs.
  • Talkback setup takes some getting used to.


SSL’s idea of applying large-format console design principles to a miniature mixer has produced a device that is compact enough to sit on any desktop, offers uncompromising sound quality and versatility, and talks USB. What’s not to like?


£2398.90 including VAT.