Diamond Dogs: Adding Subs to a VTL/Wilson System

by Roy Gregory | August 12, 2016

nybody who has read my VTL S-400 Series II Reference review will know both how highly I rate that amp and just how big a step forward it represents from its predecessor. Read my Wilson Sasha W/P 2 review and you’ll find that it has provoked much the same reaction, representing a step change in performance for the WATT/Puppy two-box platform, the biggest and most fundamental shift in the speaker’s long and illustrious history. But it gets better: as impressive as both products are individually, used together, the whole gets awfully close to delivering the best of both in a single setup. Which rather raises the question, given how far the S-400 II and Sasha 2 have come, just how much further can you push them?

It’s actually a question that was answered -- at least in part -- as long ago as the 2014 Rocky Mountain Audio Fest (RMAF), where by happenstance both products appeared, not just together but in an augmented system. Originally planned for a TAB presentation that never happened, the system in question had to tick all the high-end boxes, and we didn’t know the size or nature of the room into which it would be placed, so adaptability was the order of the day. As such, I planned to use Sasha 2s ($30,900 per pair) and a pair of WATCH Dog subwoofers ($9800 each) with controllers ($4000 each), giving adaptability to both the system itself and the setup. Amplifiers? One of the great strengths of the WATCH Dog is that it allows you to use exactly the same amplifier to drive the sub as you are using on the main speakers. In this case that meant a pair of VTL S-400 IIs ($33,000 each), maintaining the appearance of monoblocks but delivering the necessary four channels of identical power.

In the end, that presentation was stillborn, but VTL and Wilson were so intrigued by the proposed configuration that they resurrected it for RMAF -- and the rest is history. Not only was it spectacularly successful, performing way beyond expectations (remember, at this time we were still finding our way with both the principal players) with its built-in upgrade path and ability to adapt to almost any room, it caught the public imagination -- to the extent that people who heard it still talk about it in the kind of hushed, reverential tones normally reserved for milestone concerts.

Also out of that experience was born the plan that sees that self-same system sitting in my listening room. After all, if you are going to review the S-400 II and the Sasha 2, why not take it all the way to the (il)logical extreme? I’m not going to spend too much time on either the amp or the main speakers, as both subjects have been covered in depth already. Instead, I’m going to look at the add-ons -- those components that take what is an already excellent system and lift it to another level entirely -- starting with the Wilson WATCH Dog.

Sometimes the audio industry is its own worst enemy. I’ve lost count of the number of times I’ve heard the manufacturer and/or designer of a subwoofer talking about the electronics package in his latest product, justifying some off-the-shelf class-D solution because it delivers plenty of power and after all, "It’s only the bass." Since when did bass become "only" anything? In fact, low-frequency performance is absolutely crucial to any system’s musical coherence and engagement, underlined by the old adage that the only thing worse than no bass is too much bass. Bottom-end voicing and alignment are possibly the most crucial aspects of loudspeaker design, just as proper placement of any speaker, delivering optimum bass integration, can make or break a system’s performance. Yet all of a sudden, just because it’s in a separate box, anything goes -- from class-D amplification that has to coexist with the drivers in a mechanically and qualitatively destructive environment, to crudely executed filter slopes, second-rate cables and the ultimate indignity, DSP compensation -- all because it's "only" bass.

If we are going to take the issue of low-frequency energy, timing, harmonics and integration at all seriously, then just putting sensitive electronics in the same box as bass drivers should give us serious pause, while none of those other things have any place in a serious system. Remember that where you really hear a sub is through the midrange and treble, and the idiocy of handicapping it with substandard amplification, cabling and crossover components should be self-evident.

How far is too far?

One sub or two? Always two -- which makes it just as well that there’s a step-by-step upgrade path inherent to this system. Assuming that you already have the S-400 II/Sasha 2 setup, the move to double 'Dogs doesn’t have to be a single-step operation. Indeed, if you have VTL MB-450 III monoblocks ($20,000 per pair) -- a popular mate for Sasha 2s -- it’s even easier, although that’s another story, one that saves you money but costs you the very special performance benefits that come from the fully regulated circuit used in the S-400 II. Don’t underestimate those benefits or the contribution the S-400 II makes to the success of this system. It might be the speakers and subs that get all the attention, but their performance rests absolutely on the signal they receive from the driving amps, and while it is the speakers and subs that actually deliver the sound, it’s the S-400 IIs that provide that absolute authority.

Assuming that you bite the bullet and opt for the S-400 II-based system, if you want to spread the investment, then the first step would be to add a single WATCH Dog and controller, along with an amp to drive it. Assuming that a second S-400 II is out of the question at this point, you’re looking for a good class-AB monoblock or stereo amp. It can be a stopgap, but how much of a stopgap will depend on how soon you’ll be adding the second sub. One option would be to look at an amp like VTL’s S-200 II ($10,000) -- a single-chassis with two channels of enough power to get the job done at a third of the price that an S-400 II will set you back.

Step two is to add a second WATCH Dog, using the second channel on the existing controller to drive the spare channel in your stereo amp. Finally, you can go the whole hog, trading in the S-200 II for an S-400 II and a second controller. Just make sure that you keep the cabling consistent right through this process, using the same power cords on the crossover and amplifier as you use in the rest of the system, as well as the same interconnects and speaker cables. The biggest challenge with subwoofers is achieving optimum integration, which is why using the same amplification on the subs and satellites should always be your goal. At the same time, don’t handicap yourself by introducing unnecessary complications or differences into the various elements of the system. Keep everything consistent and that’s just what you’ll get -- consistent performance.

-Roy Gregory

Which is exactly why I love the WATCH Dog. It does the job right -- the perfect expression of KISS philosophy. It uses a large driver, in this case a 12" dual-spider unit. It builds that into a large, well-behaved, reflex-loaded box (almost six cubic feet in volume and weighing nearly 200 pounds) heavily braced and constructed from a carefully chosen mix of materials, including Wilson’s proprietary X material, as used in the bass cabinets of their high-end speaker systems. It doesn’t just banish electronics from the loudspeaker cabinet -- it eliminates them from the equation in that rather than choosing an amp to go with your system, it allows you to make that choice. Finally, it takes the whole question of the active crossover seriously, understanding that it needs to be built to the same standards as a serious preamp if it isn’t going to compromise system performance.

Of course, such attention to detail doesn’t come cheap. The principle appeal of off-the-shelf electronics packages is that they look good on paper, whether that’s a spec sheet or a balance sheet. But doing low frequencies properly is inherently expensive, and putting them into a separate box doesn’t actually change that.

Which might leave you wondering why anybody would bother with subs. Well, the answer is that they offer sonic and practical advantages that single-box systems can’t. Putting the bottom end into a separate box significantly reduces the mechanical challenges facing the main cabinet, with lower levels of intermodulation distortion and smaller volumes offering smaller, more rigid cabinets with the potential for superior mechanical performance and lower levels of coloration. You also get to place the woofers where they work best, exploiting room nodes, while also placing the main cabinets for optimum stereo and acoustic performance. Finally, you have the option of removing the need to respond to bass transients from the amplifier driving the main cabinets, making its job significantly easier and improving its dynamic performance -- although as we’ll see, that’s a swings-and-roundabouts situation.

In this case, the WATCH Dog and its controller allow us to take the theory to its ultimate expression. The use of separate stereo amplifiers for left and right channels means that the power supplies in each of those amplifiers are only presented with one set of really deep bass transients by the respective sub. You do have the option to run a high-pass output from the crossover into the channel driving the main speakers, but that means inserting the crossover box into the midrange signal path, and as good as it is, I’m not sure the Wilson controller matches the transparency of or drives the S-400 II as well as the VTL TL-7.5 III preamp ($25,000). In fact, I know it doesn’t, ‘cos I tried it, the decrease in load on the amplifier failing to compensate for the loss of transparency, focus and immediacy caused by the extra electronics, socketry and interconnects.

But where things get really interesting is when you add the second controller, completely separating left and right channels, but even more importantly, giving you separate control over the left and right subwoofers, allowing for differences in placement or acoustic conditions. Not everybody has an acoustically symmetrical listening room.

With the controller capable of adjusting roll-off rate, frequency, relative phase (constantly variable) and overall level, as well as also allowing configurable EQ (level, frequency and Q), it is possible to tune/compensate for almost any situation in which you might need to place a woofer. But -- and I think it’s a big but -- the less electronic muscle you use and the more integration that can be achieved through placement, the better the overall results will be. This means that, having initially placed the woofers, normally behind the speakers and close to the front wall, using the supplied setup disc and following Wilson’s comprehensive instructions will get you close. But to really dial in the subs you’ll need to play with lateral placement, height and attitude rather than the knobs on the controllers. Moving the cabinets along the wall as well as raising or lowering them relative to the floor delivers clearly audible changes in bass weight and definition, but what really surprised me was applying a 0.1-degree rearward tilt to the cabinets. It’s something that I’ve been playing with on speakers in general since experiencing Stirling Trayle at work, especially those with vertical baffles, which always seem to be happier if their bass drivers aren’t perpendicular to the floor. But I wasn’t ready for just how big a difference it made to the WATCH Dog subs, freeing up bass transients and letting not just the bass but the whole bandwidth breathe.

ith everything wired up and ready to go, it was time for the fun to begin. The natural inclination when looking at a system sporting a pair of substantial subwoofers (not to mention two fully regulated 300Wpc stereo amps) is to reach straight for the biggest, baddest recording you own. But that’s to miss the magic that the WATCH Dogs bring to this system. After all, with a claimed -3dB point at 20Hz, it’s not like the Sasha 2s really need that much help at the bottom end of their range. Instead, as with all good subs, you first hear the impact of the WATCH Dogs in the treble. Then you notice the increase in dimensionality and, once you do put on those bigger recordings, you’ll notice the apparently unlimited headroom that has suddenly become available. The addition of subs brings a wonderful extension to the already impressive sense of presence, intimacy and subtlety enjoyed by this system. They also allow it to go seriously, seriously loud.

Notwithstanding the point just made, there are some records that really do need to be played with the volume control advanced well beyond the norm, so let’s get that out of the way first, before moving on to the more delicate aspects of system performance. Classical crescendos are something I’ll return to in due course, but for a record that demands sustained high output levels, look no further than Daddy G’s DJ-Kicks LP [!K7 Records !K7170], a seminal double slab of groove-tastic remixes from the Massive Attack dubmeister. You could select pretty much anything off of this album (when Daddy revisits Willie Williams’ "Armagideon Time," the results are pretty spectacular), but forewarned is forearmed and I’d reach straight for the remix of Nusrat Fateh Ali Khan’s "Mustt Mustt." This has proper dance beats, with the motive main groove underpinned by further layers of subterranean, wall-shaking, foundation-quaking frequencies, the sort that wobble not just the air in the room but the air in your body too. It can easily all become too much with poorly defined deep bass overlapping, resonating and mushing together into a single confused, quivering blob, but the WATCH Dogs were in their element, sorting, pitching and pacing the deep synth lines, keeping the shudder of the deeper vibrato track separate from the complex textures of the crunch bass resting on top of it.

The room might never have quite stopped moving, but crucially neither did the track, the system maintaining its sense of rhythmic purpose and navigating the sudden shifts in pitch and density without apparent effort or limitation -- and that takes some doing. It’s all the more impressive because the distinctive vocals and African melodies float on the powerful wash of bass, retaining all of their stark beauty and that soulful underlying lament. The more you advance the volume control, the more solid, more present and more purposeful the track becomes, right up to the point where common sense takes over and you back it off.

Lessons learned and the price of progress

There’s no escaping both the spiraling cost of high-end ownership and the overall cost of this system. That a collection of two amps, two crossovers, two speakers and two subwoofers can set you back over $125,000 (with another $25,000 for the preamp) and yet still represent something of a bargain in overall market terms, as well as a definite bargain when it comes to performance, tells its own story. But even if that is too rich for your wallet, there are general lessons and wider opportunities that can be drawn from this experience.

As I’ve already pointed out, one of the key aspects of this system is not just the equipment but the topology in which it is employed. Critical considerations include the use of two stereo amplifiers in a vertical- biamped arrangement -- effectively transforming each channel into a virtual monoblock as far as the power supply is concerned. It is a more cost-effective (only two sets of casework) and space-efficient (only two sets of casework) approach, but also one that delivers demonstrably superior results to the traditional, horizontal approach to biamping. It also attacks the other weakness of that traditional topology, by eliminating the option to use different amps for bass and the rest of the range. In theory, that was supposed to optimize amps by function, but in reality the biggest issue with adding subs to any system is integration and that is where using the same amplifiers across the full bandwidth really comes into its own. Of course, that wouldn’t be possible without the unique arrangement of separate passive box and active crossover used by Wilson in the WATCH Dog subs (as well as the bigger Thor’s Hammer).

If lesson one concerns the virtues of vertical biamping, then lesson two is all about adding bandwidth and how best to achieve it. The WATCH Dog makes a compelling argument for its approach -- so much so that, frankly, if you are serious about producing subwoofers for two-channel music reproduction, you’d be well advised to examine it closely. Getting the sensitive crossover electronics outside of the box, allowing users to match the subwoofer amp to their main amplifier and using subs in pairs should all become standard operating procedure, preferably sooner rather than later.

Which brings us back to that small matter of cost. Even within the Wilson/VTL ecosystem, it is possible to envisage a setup built around a pair of S-200 II amplifiers, double 'Dogs and either Yvette or even Sabrina, a combination that would retain many of the core virtues of the review system at a fraction of the price -- $69,000 in the case of the Sabrina-based system. Still too steep? The basic recipe still applies, even at far lower levels of cost and performance, with dynamic range and bandwidth still delivering top-trump performance benefits. A couple of quality integrated amps, a decent stand-mount like the KEF LS50 and all you need is a pair of affordable subs/crossovers that work in the same way as the WATCH Dog and its controller to take possession of a genuine giant-killer system.

Hopefully that just started the race to be first to market with just such a product. I can guarantee there's at least one interested reviewer.

-Roy Gregory

Compared to a lot of subs, the WATCH Dog/S-400 II combination might not look that impressive on paper, with its single 12" driver and 330 tube watts, except that this is a much bigger box than a lot of subs use, there are two of them, and those are 330 real watts doing the driving. It’s not common knowledge, but the power ratings applied to the onboard amps used in most subs don’t have to meet the same standards of measurement faced by conventional amplifiers, leading to (dare I say) wimpy class-D electronics all too often being attributed with supernatural (or should that be fanciful?) power ratings, the audio equivalent of the geek in the sumo suit. The S-400 II’s bottom end is awesomely tight and powerful, articulate and agile; it just needs the proper partner to let it express itself and the marriage with the WATCH Dogs was made in heaven, not by match.com.

At the opposite end of the spectrum, listen to a solo voice and you’ll be utterly seduced by the sense of almost physical presence and dimensionality. Suzanne Vega’s "Small Blue Thing" (Close Up Vol. 1, Love Songs LP [Amanuensis Productions/Music On Vinyl MOVLP178]) is the perfect case in point. Listen to the solo voice and guitar opening on the Sasha 2s alone and it is impressively immediate and detailed, just like a really good, close-miked studio recording should be. But add the subs and the voice and instrument step back into a perfectly apparent and proportioned soundstage, singer and guitar a single, solid, 3D entity within the space, a space that makes ever more sense as the subtle accompaniment builds.

But as impressive as the subs’ spatial and dimensional contribution is, what really transforms the track is the increase in the natural delicacy and intimacy of the vocal, the easy fluidity and phrasing they bring to the guitar. Vega sounds like a more expressive, more insightful singer and lyricist, a much better player, with the shape and emphasis of the guitar perfectly underpinning the vocal nuance and sense of the song. Far from becoming overblown, the subs bring a smallness, a sense of proportion and fragility to the performance that lifts the song to whole new level of emotional impact. It’s an object lesson in just why audio systems need to deal with more than just the sonic facts if they are going to deliver the full expressive scope of any musical performance. Fragility and delicacy might not be the things you’d naturally associate with 12" drivers and big, heavy boxes, but that just demonstrates the danger inherent in visual assumptions about the musical performance of audio equipment.

Step up in scale to Alison Krauss and Union Station’s New Favorite LP [Diverse Records DIV001LP] and the delicate purity of the vocals and sparse, understated intricacy of the arrangements bring home just how effortlessly this system reveals musical subtleties and patterns, the tightness of this practiced band. What the subs bring to proceedings are not just headroom and space, the sense of individual and relative level to notes, they bring a positive clarity to their placement and spacing that only full-range systems can deliver. But in this case there’s the sort of poise, transparency and unforced, easy precision that normally only come with far bigger and even more expensive rigs, precisely because separating the bass and treating it as a distinct problem, while also doing so in a way that maximizes the chances of both effective contribution and integration, delivers performance beyond the limitations of price. Add the subs and you open a window on the music, allowing yourself to reach right inside the performance while also binding the music together and injecting it with purpose and vitality. Add the subs and you turn what is already a great-sounding system into a time capsule that moves you through musical time and space, ever closer to the original event.

Changes in venue and changes in pace present most systems with challenges that few can surpass without revealing their hand, yet with the Sasha 2s working in concert with the double 'Dogs, such transitions are so natural that they are simply part of the performance, the mechanics necessary to their passage passing utterly unnoticed. Small-scale but dynamic, acoustic or hybrid electric recordings can have remarkable musical impact (I could cite examples as disparate as Art Pepper and Ian Dury), but ultimately the bigger the forces in play the more impressive the results.

By now you might have noticed that every example I’ve cited has been a record. Even the dance music, where it seems second nature to reach for CD, comes from good old LP. There’s a reason for that, and far from it being compensatory it’s all about the strengths that LPs bring to musical reproduction, their temporal integrity and natural sense of flow and rhythmic expression. The combination of this system with a great record player is spectacularly successful precisely because the vinyl front-end really reveals just how rhythmically and spatially coherent the amps and speakers are. Far from a case of needing the help, they demand the support.

Does that mean that you can’t use the system with CD? Not at all, especially if you have one of the more temporally coherent players -- the Wadax Pre One or Neodio Origine are the top picks, but the Aesthetix Romulus does a great job too. But as far as the Sasha 2 has come, it still remains a WATT/Puppy at heart and differences in sources are clearly if not mercilessly revealed. Yes this system plays CDs -- it just lets you know that’s what you are playing. Indeed, the fundamental musical differences between the likes of the Wadax and Neodio and other less accomplished (and often considerably more expensive) options become even more apparent, the musical issues surrounding upsampling and in particular the instability and inadequacies of file replay being laid bare for all to hear.

he acid test for any audio system is ultimately the response of strangers. Since the arrival of the S-400 II/Sasha 2/WATCH Dog system, there hasn’t been a visitor from within the industry or reviewing community -- or more tellingly, one with no audiophile pretensions at all -- who hasn’t been instantly sucked into the musical performance on offer. Everybody gets this system. They get what it’s doing and why what it’s doing is special and worthwhile. It’s an object lesson in just what an audio system -- especially a high-end audio system -- should do. It’s musically coherent and capable of intimacy and delicacy, real power and scale. It is both honest and communicative. But above and beyond all that, it’s fun and engaging -- and occasionally frightening, shocking and not a little scary. It’s all the things that real music is, delivered by a system that’s built of bite-sized chunks (at least in high-end terms) and beautifully presented products.

What we have here is system in the fullest sense of the term, a set of components that seem so perfectly balanced that each one isn’t just allowed but is actively encouraged to give of its best. If you’ve ever watched Don Felder and Joe Walsh jousting through the guitar finale of "Hotel California," you can literally see them feeding off of each other: You think that’s good? Get a load of this! That’s exactly how this system sounds, as if all of its parts are egging each other on to ever-greater musical heights. Now throw in the versatility and upgradability inherent in the setup and what you have here is a modern classic in the making, a step-by-step approach path to the outer reaches of attainable high-end audio performance, one that can be scaled in its entirety or even scaled to suit.

These products represent the last staging post in the pursuit of audio nirvana before prices and practicality become really unrealistic. They are also products and a system that have delivered consistently ear-opening results across the many months I’ve been living with them -- and I confidently predict they will do so for many months and years to come. This system really is that good. The nature of the reviewer’s life means that I will inevitably be faced -- and faced quite soon -- with products that seek to offer more, bigger and better. Equally inevitably, they will do so at ever-higher prices. But the S-400 II/Sasha 2/WATCH Dog system sets the performance bar extremely high and in doing so establishes not just a benchmark that will serve to keep more extravagant efforts honest, but one that will consistently deliver superb musical results in its own right, irrespective of what happens at higher prices or with bigger boxes.

True benchmark products are rare indeed, the result of a combined sonic and sales performance that commands universal recognition and respect. Once upon a time it was a status enjoyed by Linn’s LP12 and subsequently by the Wilson WATT/Puppy, a speaker against which all other products were measured. The Sasha 2 has reclaimed that status and now, with a little help from its friends, it has extended it beyond a single product category to embrace system performance. That’s pretty darned impressive in this day and age. But for me, even that pales into insignificance against the sheer musical enthusiasm and generosity delivered by this setup. This is by any standards -- save those of high-end audio -- an almost ludicrously expensive solution to an everyday problem. It is also emphatically, triumphantly and compellingly successful: I was smitten when I first heard it in Denver and that coup de foudre has developed into a deep and lasting admiration. If ever there were a system that just keeps on giving, this is it.

For all those who feel that high-end audio has lost its way, who respond to the latest six- and seven-figure product price tags with understandable cynicism or just want to get off the product upgrade merry-go-round, this is a system you should hear. It may not answer every need or every question, but that it is an answer is indisputable and it may well be the answer to a question we’ve seemingly lost sight of: just what exactly should a high-end system do? In a world where so many products promise so much and deliver so little, where the gap between marketing hype and performance reality yawns ever wider, this is a system that does just one thing: it brings performers and their performances into your home -- and it does it brilliantly. It delivers on the promise of the products it contains and it delivers -- in the most straightforward, direct and uncomplicated way -- on the promise of high-end audio itself.

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