Blackbox Analog Design HG-Q

This hybrid valve/solid‑state processor offers some unusual facilities — not least the ability to be remotely controlled from your DAW.

While we may not need analogue outboard today, plenty of us are still very drawn to what it has to offer. But as I discussed in a recent SOS podcast about ‘hybrid’ studios — those that use a combination of analogue outboard and software — even engineers who have racks full of high‑end equipment can sometimes struggle to integrate their hardware into modern workflows. And the most commonly cited reason for reaching for a software equivalent? It’s very simple: recall.

To address this, a small but increasing number of manufacturers have been developing recallable analogue hardware that combines the sonic appeal of analogue processing with the convenience of digital control and often software‑based workflows. The SSL Odyssey reviewed elsewhere in this issue of SOS is a striking example, but Bettermaker, Wes Audio, Cranborne Audio, Tegeler Audio and several others have delivered elegant plug‑in controlled analogue processors in recent years.

The Blackbox Analog Design HG‑Q I’m reviewing here is another. For all practical purposes, it’s a high‑end but fairly conventional analogue equaliser, complete with a tactile front panel that’s been designed to allow traditional manual operation. But the LED rings tell you the knobs turn endless rotary encoders, not pots, which in turn suggests there’s a little more going on behind the scenes. Below, I’ll examine the HG‑Q’s merits as an EQ, of course, but I’ll also consider whether the hybrid approach genuinely makes this hardware more practical in modern production workflows than conventional analogue outboard.

Design & Concept

The HG‑Q, housed in a substantial 3U, 19‑inch rackmount chassis, is a stereo three‑band equaliser with a hybrid solid‑state and valve topology. Each band features separate cut and boost controls that normally operate in series (more on the alternative below), and the solid‑state cut/boost stages result in a clean‑sounding, flexible EQ. Each band’s boost stage, though, can introduce more character if desired: pressing its Sat button engages a parallel valve stage, which contributes different amounts of saturation according to the signal level.

Frequency selection is switched per band too, with a choice of eight fixed frequencies: 30, 50, 70, 100, 140, 200, 280 or 400 Hz for the low band; 22, 330, 460, 650 or 900 Hz, or 1.2, 1.8 or 2.5 kHz for the mid band; and 2, 3.5, 5, 6.5, 7, 10, 12 or 15 kHz for the high band. The bandwidths are adjustable too (16 fixed points), and at its narrowest settings the HG‑Q is capable of precise, surgical cuts.

By default, each band offers up to 8dB of cut or boost, but the central global control section includes a 2x button that doubles this to ±16dB, for more radical processing. So while an EQ like this would be very at home employed in a mastering setup or on a stereo bus, it should be just as good for shaping source tracks in a recording session.

Things can become still more interesting if you press the Par button adjacent to the cut control. Doing this changes the EQ topology, arranging the boost and cut stages in parallel and then summing their outputs. This gives you access to the sort of simultaneous boost‑and‑cut behaviour often associated with classic Pultec‑style equalisation, but it’s considerably more flexible than that — not least because a band’s cut and boost stages can be set to different frequencies, and the phase interaction between those parallel paths means more complex tonal shaping is possible.

As well as power, bypass and the aforementioned 2x mode, the centre section hosts controls for managing stereo operation. The two channels can be linked, run independently in dual mono, or configured in Mid‑Sides mode, with the necessary matrixing handled in the analogue domain. In this mode, the Mid and Sides channels can each be soloed, making it easy to hear exactly what’s being processed. Completing this centre section are a 12dB/oct high‑pass filter (20, 35, 40 or 100 Hz) and an attenuation control with four settings, marked simply 1‑4.

The HG‑Q communicates with its remote‑control plug‑in over a USB connection to the host computer.

The rear panel is uncluttered: an IEC power inlet is joined by a USB connection for the software remote control, plus two pairs of XLRs for the balanced stereo analogue I/O. Unusually, those XLRs are arranged as an input pair and an output pair, rather than the connectors being grouped by channel. I can see the logic, but personally I’d find the latter configuration more intuitive.

First Impressions & Physical Interaction

First impressions of the HG‑Q are of a substantial piece of equipment. It feels solidly built and has reassuring weight to it, and the plain black faceplate hosts both clear legending and a comfortably spaced control layout. The encoders feel good in use, too. Each one has a detented action, a brightly illuminated LED ring, and a satisfying ratcheted click as it moves from position to position.

The translucent switches feel a little less premium, offering no tactile click when pressed — instead, you push them in, they illuminate bright blue to indicate their state, and pressing again extinguishes the light. It works, it supports the recallable nature of the unit, and some will welcome the silent operation, but I do miss the satisfying confirmation of a more mechanically positive switch action!

The LED implementation is very effective, with multi‑colour illumination used throughout, and the Black Box logo is also illuminated blue in normal operation, changing to red in certain control modes. Inevitably with so many lights, the whole ensemble can be rather colourful and in a dark studio, the default LED brightness is on the assertive side, and will likely be a little ‘shouty’ for some engineers’ tastes. Thankfully, then, holding the cut control on band two allows the brightness of the red and blue encoder LEDs to be adjusted independently. I couldn’t find any equivalent control for the illuminated buttons, though, so they’ve remained fixed in brightness. But in practice, having at least some control over the visual intensity does makes the interface considerably more adaptable for use in different environments.

The power switch sits inside a rubber boot, presumably to protect it from the ravages of dust in the coming years. (Hopefully it isn’t intended to keep water out, because water should have no business anywhere near a unit like this!)

In use, the HG‑Q’s case remains cool. As you might expect, there’s a faint warmth emanating from the valves, but there are ventilation slots on both sides of the chassis and I didn’t notice any significant heat build‑up, even over extended sessions. I wouldn’t expect thermal management to be a problem when it’s installed in a studio rack, then. (Even so, I’d always leave 1U of rack space free above valve units like this, so as to ensure good airflow.)

In terms of operation, the HG‑Q is mostly very intuitive and, thankfully, its settings persist through power cycling, meaning the HG‑Q can behave exactly like conventional standalone hardware if that’s how you prefer to use it. But the manual is absolutely worth reading — it describes some genuinely useful operational shortcuts and functions that it would otherwise be easy to miss. For example, one of my favourite features is a shortcut that zeroes out the EQ entirely: you simply press and hold the left‑channel low‑frequency cut control until the Black Box logo glows red, then press it again. It’s a thoughtful touch that makes resetting this unit quick and painless.

You could actually think of the HG‑Q as a six‑band stereo EQ with some shared controls...

There are quite a few hidden features, in fact, mostly accessed by pushing the encoders (they’re all dual‑function push‑turn types), and it’s well worth familiarising yourself with them. The most essential is engaged with a momentary press on a cut encoder — this toggles that band in and out, and it can be an extremely useful way to audition what that particular band is actually doing without having to zero your cut/boost settings. The push actions also access deeper control, including the ability to assign different frequencies and Q values to the cut and boost stages in a single band — meaning you could actually think of the HG‑Q as a six‑band stereo EQ with some shared controls, rather than a conventional three‑band one.

Standalone Operation

As is clear from the lofty asking price, the HG‑Q was conceived by its manufacturers as a serious piece of outboard that can stand on its own merits as an equaliser, whether you’re using it for mastering, mix‑bus duties, or for more assertive channel shaping. And although using the HG‑Q purely as a standalone EQ would mean missing out on one of its key selling points, it makes sense to start there...

Operating the HG‑Q feels every bit as immediate and hands‑on as analogue hardware should. Setting it up for use as a hardware insert in Pro Tools was quick and straightforward, and so too was dialling in the desired EQ settings. The hardware controls are all very comfortably spaced and have a positive action, and the legending is clear, so all in all the control panel is effortless to navigate.

Some might find preset frequencies limiting compared with a continuously variable control, and that’s a valid perspective, but I’ve always liked fixed‑frequency EQs, and am a fan of Neve‑style designs in that regard. With eight frequencies available per band, plus a little overlap of the bands’ ranges, the HG‑Q seemed to me to be capable of handling everything short of the most forensic corrective work. And I wouldn’t usually reach for an EQ like this to hunt down a ringing overtone in a snare drum anyway...

Used on mix buses, stereo programme material and individual source tracks, I could achieve everything I wanted. In stereo, the linked operation speeds things up considerably, and the option to switch to Mid‑Sides EQ is a genuine gift. And when deploying the HG‑Q as a channel EQ, I found the 2x mode particularly useful — the bigger boosts and cuts make far more assertive tone‑shaping possible.

The attenuation control warrants explanation, since it’s not a conventional output level pad: the attenuation is in 1dB steps, up to a maximum of only 4dB. Its purpose is to offset any overall gain increase due to EQ boosts and saturation. You might expect the parallel valve boost stage to introduce more gain than that, but the HG‑Q’s dynamic gain compensation system actually keeps level changes within a sensible range.

DAW Integration & Recall

The key selling point that I alluded to above is the HG‑Q’s remote‑control DAW plug‑in. This makes possible the instant, accurate session recall that’s so important to today’s production workflows. I tested this side of things using the plug‑in in Pro Tools, and just as I’d hoped everything was always recalled seamlessly, with the LED rings and illuminated buttons snapping to the stored settings.

The benefit for anyone working with a hybrid setup should be obvious. Manual recall of a switched EQ’s settings is fairly quick, but accuracy is important. The HG‑Q’s approach eliminates the risk of human error. One of the two remaining pieces of outboard I have in my studio is an EQ, but despite my unwillingness to sell it, it rarely gets used, simply because recall is so much more convenient and always accurate when I use a plug‑in. Having a recallable analogue mix bus EQ is something I could get used to.

The plug‑in resembles the hardware but also displays familiar plug‑in style EQ curves (which can, if you wish, be hidden).

There are several different ways manufacturers are currently approaching recall in analogue hardware. McDSP’s APB for example, is only controllable only through its plug‑ins. Others, such as Bettermaker and Weiss, use onboard screens, and don’t rely exclusively on a host computer. A handful use motorised controls alongside a plug‑in, which not only adds to the build cost but, one suspects, may mean long‑term reliability considerations, simply by virtue of adding moving mechanical parts. Others, such as Wes Audio, Cranborne Audio and, on their latest mixers, SSL, employ endless rotary encoders with LED‑ring position indicators, along with software/plug‑ins.

The Black Box is in that last category, and the approach has rather won me over — it sits in the sweet spot between the tactility and immediacy of analogue outboard, and the convenience and workflow benefits of the DAW. You gain all the practical benefits of recall and DAW integrations, without being overly dependent on screens or software.

I also find working with this sort of hardware simpler and faster than with software alone. I tried a simple experiment, setting up a Mid‑Sides EQ on a mix: a little high‑frequency shelf on the Sides, some simultaneous parallel cut and boost at the low end, and a modest midrange adjustment on the Mid channel. It took seconds; I could have configured it, listened, reset, and reworked it multiple times within a minute. Then I attempted the same process using FabFilter’s Pro‑Q 4 plug‑in, which has one of the finest EQ interfaces ever created. I couldn’t get close to the same speed.

Partly, that’s due to some genuinely thoughtful workflow touches. Tapping to cycle the frequency and Q controls through boost‑only, cut‑only, or both, is quick and extremely intuitive. So too is dialling in an offset between the cut and boost stages. Resetting those offsets and bringing values back together takes mere seconds: link the controls, rotate the encoder fully in one direction, and you’re done. Good use of colour also helps: blue LEDs indicate boost, red ones cut, and they’re purple for both.

The plug‑in’s EQ curve is a welcome feature, but so too is the fact that it can be hidden — engineers primarily driving the hardware from the plug‑in should appreciate it, but others will prefer to treat the hardware as the primary interface and either find the curve distracting, or that it takes up valuable screen space in the DAW.

Personally, I wouldn’t anticipate automating this sort of EQ during a song (I’m sure many would!), but I could see myself wanting to automate the switching from one setting to another between tracks in a mastering session. Automation works just as expected when writing automation from the DAW, whether using the plug‑in GUI or writing automation directly in playlists. What you cannot do is record automation using the hardware controls. But because of the stepped nature of this EQ, with discrete fixed frequencies, steps in gain and Q, this doesn’t matter in the way you might think — the potential for sweeping parameters while passing audio is limited by the EQ itself, not the way the control system has been implemented. Still, it’s important to understand the limits of what’s possible.

What you can do is quickly switch between four banks stored with each patch in the control plug‑in, and this makes it easy to compare different settings. We’re used to this sort of fast A/B comparison in plug‑ins, but being able to do it with analogue hardware is very useful. As someone who would choose the front panel over the plug‑in, though, I’d have liked some way to toggle alternative settings from the hardware itself, a facility offered by some of the competition. Of course, when you’re spending this kind of money, you expect more than workflow convenience alone...

The Sound?

Having used it in both mix and mastering applications for some time now, I can happily report that the HG‑Q is something of a ‘grower’. Initially, it was a case of waiting to be convinced, partly because I expect great things of expensive units, partly because manually recalling something as simple as a stereo three‑band EQ isn’t that difficult, and partly because there are some compelling software alternatives (not least the plug‑in version of the HG‑Q, which I also installed and tried!).

Much of the time I found myself using this extremely flexible EQ in broadly the same way that I’d approach my favourite broad‑brush equalisers (a Universal Audio Pultec and Kush Audio’s Clariphonic). And after a few days of use, I kept returning to the same conclusion — it really does make things sound better simply by being in circuit.

As for the EQ, what struck me most was how, when placed alongside the HG‑Q, my software equalisers sounded aggressive by comparison. The HG‑Q’s top end is certainly effective, but it’s consistently soft and pleasing too, never straying into ‘brittle’ or pushing the transients. At the low end, it can be clean, but there’s that saturation effect too, and that can be irresistible. (One small frustration, by the way, is that there’s not a global way to toggle saturation in and out from the hardware or the plug‑in.)

I found it particularly effective in the midrange, which it can shape in a very satisfying way. The overlap between the low and mid bands is enough to cover the octave between 200 and 400 Hz, where ‘body’ and ‘mud’ can coexist, and the independently configurable boost and cut bands give you the flexibility to address both if required. Engaging Par mode and dialling in simultaneous cuts and boosts opens up a great deal of sonic territory, from subtle through to far more attention‑grabbing tonal shaping, if that’s what you’re after.

The valve saturation (note that you must have a boost in the band for the saturation control to have any effect) ranges from the subtlest colour to satisfyingly hairy. Used at low to moderate settings, it’s particularly appealing and I found I opted for this effect more often than not. If pushed to extremes, it’s perhaps not at its best, but it doesn’t have to be subtle if you don’t want it to be. All in all, it’s pretty addictive.

Conclusion

Inevitably, people will compare a unit like this with software EQs, since they’re readily available, incredibly versatile and relatively affordable. Indeed, I’ve already done so above. But it’s really not a fair comparison; if your purchasing decisions are driven purely by value, in the narrowest cost‑to‑benefit sense, hardware can’t compete with software today. It never will. That’s not why products like this exist.

More useful is comparison with other hardware EQs. There are lots of recall‑friendly mastering equalisers with detented controls, and especially in mastering environments that approach is perfectly manageable. But ultimately, what Black Box are selling here is a high‑end EQ, that not only sounds good but also offers significant workflow benefits — this sort of accurate, total and instant recall feels to me like a much better approach, particularly when you’re dealing with a whole processing chain or mixing setup. There are alternatives in this space too, from manufacturers I mentioned above, and a studio built around this sort of recallable equipment could be a very tempting proposition for anyone who can’t reconcile outboard with the way we work today! Finally, although the HG‑Q is undeniably expensive, in that context, it’s certainly not the priciest option, and its value should be immediately obvious to the sort of customer Black Box have in mind.