Having reviewed the Wilson Duette as recently as Issue 47, and revisited it in Issue 48, with no major (or even minor) revisions made, ordinarily there’d be no reason to cover it again so soon. But this project dovetails so neatly with our ongoing discussion of sub-woofers and adding bass extension that it’s simply too good to miss. Besides, I don’t need that much of an excuse to get reacquainted with what is fast becoming a firm favourite of mine.
The Duette is a fantastic musical performer with its scale, musical coherence and balance, surprising dynamics and a beguiling tonal beauty. To get that degree of musical authority and integrity from a package that is at once as tractable (as in easy to place, easy to drive and easy to accommodate) and versatile as this is, frankly amazing. This is the little(ish) speaker that breaks all the rules. It’s too big to be small, too expensive to be a bargain, too small to have real bandwidth and not expensive enough to be taken seriously. And it breaks those rules by performing a balancing act more impressive than the great Wallenda doing a one-handed stand, atop a chair, half way across the Niagara Falls. So sure footed is this little gem that what matters is there and what isn’t you don’t notice. The only area in which you can dent its poise is with serious low frequencies, where it simply can’t match the weight, texture, dynamics and transparency of bigger speakers – which is what leads us to the WATCH Dog. other side of that coin is that they wouldn’t work very well run full-range, or necessarily blend well with your main amps that are designed to do just that. Which is in turn why so many sub manufacturers want to run their products from the speaker outputs of your amplifier – overlaying (as they describe it) the sound of the main amp onto the sub’s electronics.
Now, I can see how the sonic imprint of one amp, laid across the character of another might be less obviously damaging than running two dissimilar amps side by side to furnish a single audible range. At least you gain a degree of consistency. I can also appreciate the financial benefits of shoving everything into a single box – especially as buyers seem to assume that bass from sub-woofers should be cheaper than bass arrived at by more conventional means. However, there’s no question in my experience that this approach costs you transparency and bass texture – and I don’t even want to consider what the output stage of your amplifier thinks about all this. There has to be a better way – and there is.
Although the filter electronics for a sub really do need to be active, there’s no requirement for them to be inside the sub-woofer cabinet itself. In fact, if we actually functionally separate the various elements that constitute a sub, we end up with three boxes – an active crossover, an amplifier and a speaker cabinet. Given that doing so is much more expensive (that’s three sets of cabinet/chassis parts instead of one) less physically elegant and demands additional ancillaries such as cables, which are also far from cheap – why would anybody bother? Because doing so enables you to overcome all those issues outlined above. The active crossover can be driven directly from your pre-amp outputs, the best place for it. The amplifier is no longer subject to the indignities heaped on it inside the woofer cabinet and what’s more, if you design your speaker with care, there’s no reason why you can’t use an identical amp to drive it to the ones you are using on the rest of the range. So physically elegant it isn’t, but conceptually speaking it’s got a lot going for it – just as long as quality considerations outweigh cost. Wilson’s passive WATCH Dog is exactly such a device, a derivation of an older, active version of the same cabinet, now offered sans electronics and thus with slightly reduced dimensions. Instead, there’s a sophisticated active controller built into a standalone rack-mount chassis and the owner gets to choose (and pay for) his own amplifier to drive the beast. And a beast it is, a single 12.5” twinspider driver employing a doped paper cone, massive voice-coil, a single-roll surround of heroic proportions and a suspension so stiff it barely moves. The driver is built into a massive, bluff cabinet constructed entirely of Wilson’s proprietary X material, a foot and a half wide and two foot tall and deep. The bottom edge of the cabinet opens into a full width slot port, and all 211 lbs of it sits on four substantial conical feet and spikes. The price is not insubstantial either, at close to £6.5K, but at least you are aware of what you’ve paid for – every time you pick it up!
If the WATCH Dog cabinet is all about carefully applied brute force, the controller is all about sophistication. Specifically designed to be equally at home in a home theatre or two-channel system – or indeed both simultaneously – it will happily accept and switch between line and LFE inputs. It will also operate single-ended or balanced, while giving you adjustable low and high-pass filters (just in case you want to roll-off the bottom of your main speakers too). As well as adjustable slopes (6 or 12dB/octave high-pass, 12 or 18dB/octave lowpass) and a crossover frequency range of 30 to 150 Hz, you get a level control and a continuously variable phase control. Finally, there’s also an optional EQ section that can be switched in to tackle specific room anomalies, allowing the user to select the frequency, Q (width) and degree of bass boost or cut. As the manual makes clear, its application is specific and using it to simply increase bass output will cause more problems than it provides “benefits”. Fortunately, it wasn’t required in my room. The Controller weighs in at £2.3K and will drive either one or two WATCH Dogs, depending on your craving for bass and the depth of your pockets. With all those options available, set-up could be a bit daunting – but then I had Pedro from importer We’ve looked at single subs and we’ve looked at pairs of subs. Time then to take the next step in examining the great Achilles heel of add-on bass – integration. After the issues of placement and parameter adjustment, the greatest obstacle to the successful use of any sub-woofer is the sonic character of the device itself and how it’s physically integrated into the main system. If we accept for a moment that the vast majority of sub-woofers consist of a cabinet containing one or more drivers and the electronics necessary to drive them as well as filter the signal they receive, a number of issues immediately emerge. First and most obvious is the quality of the electronics themselves. If they are not at least as good as your pre-amp, placing them anywhere between your pre-amp and the main speakers will cause unacceptable degradation of the vital midrange. I’m afraid that, given the cost and difficulty of creating a high-quality pre-amp, few of the filter circuits used in subs qualify. Which is why most subs are rolled up under the full-range output of the main speakers, run from parallel pre-amp outputs, or from the speaker outputs of your amplifier, again connected in parallel. The second obvious issue is placing delicate electronics inside the vibrating chassis of a subwoofer – especially given what we know about the vulnerability of circuitry and individual components to mechanical interference. Finally there are questions concerning not just the quality but also the sonic character or nature of the amplification itself. The need to supply serious power to generate real low frequencies (even with active equalisation) has led designers to ever more powerful amplifiers, often employing Class D operation. Now, while that isn’t true of every sub, I can pretty much guarantee that whatever amp is used will be optimised for low-frequency performance – hence the popularity of Class D designs. Of course, the Absolute Sounds, and so would you. Or another, Wilson trained installer, which is the beauty of buying a Wilson product. They may be expensive but you know you are going top get the performance you’ve paid for because they make damn sure you do. In practice, it took longer to position the Duettes, running fullrange and in free space naturally, than it did to adjust the sub-woofer. Wilson also supply a really well thought-out set-up disc and a set of clear and logical instructions, so the technique is well-established. Once you’ve seen it done you’ll be confident enough to play a little and refine things if needs be. We started out by driving all three speakers from three separate but identical channels of an Audio Research D150M multi-channel amp. Despite being one of the better sounding digital devices around, it was clear that the speakers could deliver an awful lot more. The problem is, finding a suitable threechannel amp, or just three channels of identical amplification full stop. Fortunately I still have in-house the three VAS Citation Sound 2 monoblocs reviewed in the last issue. Three channels certainly, but suitable? Only one way to find out…