The BIG Picture Review:

Sponsored in part by:

SVS PB2-ISD a.k.a.
"Powered Box, Dual ISD Woofer"

Reviewed by Jeff McNeal

Something wonderfully wicked, this way comes...

When SVS shipped their large bass tube to us for review a couple of years ago, it was a revelation. Resembling a gigantic cat scratching post (but our two cats never dared venture near it, thank goodness), the SVS 20-39PCi was a futuristic monolith that became quite literally, the cornerstone of our sound system here at The BIG Picture, and a welcome fixture at that. Frankly, we couldn't imagine how SVS could have improved on the performance. While by no means was the SVS 20-39PCi at the top of their product line, we were suitably impressed with the huge difference in performance and improvement over an older, typical amplified "cube" subwoofer in roughly the same price range that we had been muddling by with for years prior to the arrival of the SVS 20-39PCi. This was a speaker that surprised us by outperforming more expensive subs.

I was speaking with a home theater vendor not too long ago, and he related the story of a wealthy doctor who ordered a set of $30,000 high end speakers for his home theater (gulp) but made the stipulation that the SVS subwoofer was to remain in the system and not be replaced. So what does the good doctor know that you don't? The same thing that we've discovered for ourselves around here.

SVS, an American firebrand company, has managed to figure out how to gather the finest components from various sources, nowadays from SVS custom specifications, then assembles these components into durable, well-designed speaker cabinets that rival the most expensive in the world, at a fraction of the cost. When we say "gather", we don't mean to imply that SVS hangs out at the swap meet on Sundays picking up surplus parts off a card table. In the earliest days of the company, they looked for ready-made components, but that was when they were a brand-new start-up. These days, SVS has an active hand in the design of all the components, not just the cabinets. Take for instance their North American built amps (does that suggest Canada? -- you bet it does). These BASH amps are slick, efficiently designed power plants that run cooler and pump out more usable power than a lot of what's on the market, when combined with the elegant and efficient cabinet designs that SVS installs them in. While the speaker magnets may come from Asia, the woofers themselves are built in places like San Diego, or as in the case of the ISD drivers used in this product, Las Vegas, Nevada. All to SVS design specs, naturally.

The current line-up of eight self-powered SVS products feature five custom digital amps and six speakers of varying power and design -- all proprietary to SVS that you won't find in any other manufacturer's box. Even the shipping boxes are subbed out and unique to SVS. In summary, it takes a great coordinated effort to come up with this product -- and SVS is obviously up to the task. They're taking back a market share once dominated by Germany and Japan with their aggressive designs and marketing strategy. There's one other nice "fringe benefit" of buying through SVS. You can proudly point to your new sub and proudly state "Designed and made in the U.S.A., baby."

Though SVS has forged their reputation on their tubular subwoofers, they now offer consumers a choice with their line of "cube-ular" cabinets. The PB2-ISD is such a cabinet, employing two, large, downward-firing drivers and not one, not two, but three tunable bass ports, that allow you to tailor the frequency of the lowest bass you want, given your room configuration and personal preferences.

Recently, Ron Stimpson, who wears the hat of Director of Customer Service at SVS, asked if we could tear ourselves away from the 20-39PCi long enough to give the PB2-ISD a try. Are you kidding? That's like asking someone on the Atkins Diet if you can throw a lobster on the grill after they've been feasting on filet's for awhile.

We weren't quite sure what to expect in terms of size and weight, but were suitably impressed by the great struggle that the delivery man had as he grunted and groaned bringing the box into our theater room on a large hand truck. If you've never seen an SVS product in person, the first thing you will notice, and no doubt be impressed by, is the packaging, which they have assembled with the same care and foresight as the audio component that's so very well-protected inside. Although we weren't sure we'd be moving to another location in the middle of our review, we kept the packing materials and boy, did they come in handy.

Once we cut the straps and got inside the box, we noticed even more dense foam packing material in two of the three bass ports. These are actually used to "tune" the bass response from the sub. With no ports blocked, you get a low bass frequency extension down to 25Hz. By blocking just one of the three ports, you get a bass note extension down to 20Hz and with two ports blocked, the bass notes can be heard as low as 16Hz, which you really don't hear as much as feel. Yup. You guessed it. We settled on blocking two of the three ports. SVS includes a handy, color-coded frequency response reference chart with each sub that helps you visualize what happens when the ports are blocked or opened up.

The unit it itself is large and extremely heavy (roughly 150lbs), with 1-inch thick enclosure walls in the construction. Due to the size and weight, you really need two people to get it into position, preferably in a corner of your room. Whereas the tube subwoofer was wrapped in sort of a felt material, the PB2-ISD is housed in a lightly textured finish in what appears to be heavy gauge ABS plastic. To stress the sturdiness of construction, we would have no aversion to standing atop this thing to change a light bulb if we had to -- not that we ever would, mind you. The PB2-ISD beautifully designed and built -- think of it as the Humvee of subwoofers. Amazingly, this rectangular shaped cube, with soft rounded edges, disappears nicely into the corner of the room and is even less conspicuous than a tube subwoofer that takes up less than half of the same floor space. Controls on the back panel include volume/gain, crossover frequency, phase, line in/out, auto on, crossover enable/disable switch, high level ins and outs in case you don't have line level outs on your receiver or amp. Not to be cruel, but if your sound system doesn't have low level outputs, it's time for a new receiver or amp. However, not to spoil anyone's joy, SVS includes those binding posts anyway -- just in case.

My only complaint about the construction are the little adhesive backed rubber feet that can be attached for hardwood or tile floor installations. They simply do not stay in place very well and if you make the mistake of trying to shove the PB2-ISD even an inch or two, the feet are going to fall off. Frankly, it's hard to think what SVS could have done differently to get around this problem, but I like to think that I'm a creative guy, too -- and I've come up with an idea: Countersink permanent rubber feet into the bottom of the case itself. Another option would be to have threaded fittings in the case and screw in optional rubber cones on threaded studs like the ones that are used to align the hood (bonnet) assemblies on old Triumph Spitfire sports cars. SVS, if you're reading this, I've got a cheap source of these threaded rubber cones if you're interested. I need to stress that the adhesive backed rubber feet were my only complaint about the otherwise outstanding construction.

Bass port tuning takes a bit of experimenting with before you find the threshold of sound pressure you're most comfortable with. By plugging the ports and forcing a lower response, you'll be limiting the high bass frequencies to enhance the imaging of the lower frequencies, which don't occur as often, but when they do! After adjusting levels both on the back of the sub and on our receiver, we finally settled on blocking one port to emphasize the range of frequencies around 20Hz for awhile (we eventually opted to block off two ports for even lower bass response). This seemed to solve an annoying problem we've been living with for a long time It seems that our wood double-hung windows love to shake, rattle and roll at about 25Hz or some frequency above that threshold. By using the bass port tuning to direct mainly 20Hz or lower frequencies for emphasis, we hardly ever rattle the windows anymore, but we certainly manage to feel the vibrations in our chest cavities. Correction -- my son reported that his bedroom window -- about 30 feet away -- rattled during the earthquake scene in FREAKY FRIDAY.

The SVS owner's guide is a decidedly low budget affair in keeping with a stealthy company that would rather devote their energy and resources to their product line, but it's written in an extremely user-friendly way without a lot of techno-jargon. We wish that it included a tiny bit more information, like technical specs, for example. While a nice line graph to show the effects of bass port tuning is included, I'm the sort of guy who likes to know how many RMS watts that black beauty in the corner has stashed inside it. Whatever it is, it seems to be plenty -- and then some. One of the first truths of audio reproduction that I learned is that it's always better to have at least half as many watts of power available than you will actually need or use on a regular basis. The end result is usually a smoother, less distorted sound. SVS is a bit coy on the power rating for their BASH amplifier, but stress that the power outlet should be able to handle a "minimum" of 600 watts. The sub employs dual, 12-inch ISD (Improved Standard Driver) woofers housed in a 115 pound, 18W x 25T x 28D cabinet, with those detachable rubber feet for placement on hard flooring surfaces.

One of the questions I receive the most are from audiophiles wondering how well these subs handly the subtle nuances of musical performances. As impressed as I was with the 20-39PCi, I was expecting great things from the PB2-ISD and I certainly wasn't disappointed. This, coming from a guy who has been involved in professional audio production for over a quarter century, as of this writing. Music was important to me long before films on DVD were, and so one of the many "real world listening tests" I put this sub through involved listening to music. Because of the way my receiver/amp is configured, the only way to get signal to the sub channel is to either listen in Dolby Surround or Dolby Digital 5.1 modes. The subtle refinement of the bass response mentioned above lends itself exceptionally well to music. I listened to the 5.1 surround mixes of several audio CD's I have, including THE DOORS and FLEETWOOD MAC'S RUMORS. I plopped myself in the middle of the room and sat there listening with a stupid grin on my face for a few hours one afternoon. One thing that struck me was that I didn't have to re-adjust the volume on the subwoofer as I've usually had to do when switching from movies to music. It just didn't seem necessary this time. Musically speaking, I'd have to sing high praise for the precise, crisp way that the PB2-ISD handles the bottom end of the music I've heard so far with it.

After living with the PB2-ISD for about a month, the differences between it and the 20-39PCi became readily apparent almost immediately Due to the dual large-cone driver configuration and beefier amp, and perhaps the cabinet design and port system as well, lower bass notes that escaped our attention before are more readily noticed (and adored) now. Far from being an overpowering or distracting presence, we would describe these "newly unearthed" bass notes as being more refined and subtle than any subwoofer we have ever heard to date.

Besides hearing more bass than ever before, the most important thing we can stress is that it sounds more natural then we've heard before as well. Take the lion that roars at the beginning of every MGM movie. For the first time, Leo actually has some balls to go with that famous growl. We watched a wide variety of DVD's, from music to film, and came to the conclusion that as much as we love the groove tubes that SVS have made so many audiophiles happy with, we're going to go"cube-ular" for awhile. One interesting aside -- while the bass response seems richer to our ears, we're not getting as many complaints from the room next door, perhaps owing to the fact that we feel like we can get away with less volume than we did before, yet retain the same "oomph" that we've come to know and love.

This review was originally slated for publication in February, 2004, but a massive hard disc crash wiped out our first draft, prompting a total re-write. In one sense, we're very glad it did, because we hadn't yet viewed MASTER AND COMMANDER on DVD in February. All I can tell you is that when coupled with the SVS PB2-ISD, the soundtrack nearly becomes a religious experience. The opening battle scene astounded us as no other soundtrack we've tested with this speaker has to date. The low frequency rumbles are so pronounced at louder listening levels, that we've had guests inquire about the "bass shakers" installed under our floors or under our couch. Only thing is, we don't have any bass shakers installed. Just the PB2-ISD, which at around $900, outperforms other subs costing significantly more. Shakers? We don't need no stinkin' shakers!" My sister, who fancies herself an audiophile (and has a home theater setup that confirms it), said "this sounds better than our subwoofer -- and we paid a lot more for ours than that!"

There is no question that SVS is a leading purveyor of all that rumbles -- and rumbles well. This is one wicked subwoofer, and even if you have to stretch your budget to attain one, I can assure you it will be worth it -- and you will thank me later.

If you have more questions and would enjoy further objective discussion about the SVS PB2-ISD powered subwoofers, enter our discussion forum here at and let's talk about it!