When the subs arrived, I decided to test them in three different ways. First, I would use one by itself to see how well it could handle a large room. Next, I’d use both subs, positioning them close together. Last, I’d put one sub each in my designated subwoofer locations in my room. The back of the Speedwoofer 10S includes three knobs—volume, internal crossover, and phase—along with a crossover bypass switch, stereo RCA in/out jacks (allowing you to daisy-chain another subwoofer with ease), stereo speaker-level inputs, a power switch, a detachable power cord, and a wireless pairing button. There’s also an LED that signifies the power status (red off/blue on), but I found it much too bright, lighting up the wall behind the sub; I like my room completely black on movie night. This is a vented sub, but in lieu of a traditional round port, there’s a slot vent along the bottom front. In Use My room is prewired for subs in multiple placements, so setting up the Speedwoofer 10S was a breeze. It performed best in my closest-to-the-listener position along the right wall, which surprised me given the sub’s size. Most small subs crave a corner placement to maximize room gain, but that definitely wasn’t the case here. After calibrating with my sound meter, I fired up some tunes to see what this little guy could bring to the table. First up was “Brass Monkey” from the Beastie Boys’ Licensed to Ill—yes, I really wanted to hear how well this sub could thump. I set my Marantz pre/pro to reference 0 and was shocked by how pronounced the bass was. In fact, I had to double-check that I had disabled my SVS sub—I was amazed that such a small sub could produce so much room-shaking bass. I’ve had other small subs in my room that could play loud, but I haven’t had one that could actually shake my subfloor till now; usually, only the big boys can do that! If one Speedwoofer could produce this much bass, what could two adjoining subs do? Out came the second sub, and I connected the two with an RCA cable from sub 1 to sub 2. I placed the second sub on top of the first and then side by side with it, to see if that made a difference—it didn’t, at least in my room. After recalibration, I resumed testing, and I found that the two subs together were even more impressive, with everything I threw at them. Knowing how two performed together, I then moved the second sub to my front left corner and ran a third calibration—and I really liked what I heard. This definitely evened out the bass response throughout the room on hard-hitting bass sequences from the Extended Edition Blu-ray of The Lord of the Rings: The Fellowship of the Ring, such as the appearance of the Balrog and the thunderous footfalls of the Nazgûls’ horses as they pursue the Hobbits through the forest. The trade-off was less overall output, since the subs were separated. Frankly, I’d love to have four of these in my room, two in each sweet spot—now that would be fun! Ultimately, though, the majority of my testing was done with one sub in the closest position, and I never found the bass lacking at modest listening levels—which is how I do the majority of my viewing and listening. It was only during some thunderous, bass-intensive scenes played at reference level that I felt the sub couldn’t keep up with my reference subs. Frankly, for a $399 sub to even be in the conversation is the highest compliment I can give it. I also tried the Speedwoofer 10S’s wireless option, a $50 premium. It adds a wireless transmitter, allowing you to place the sub anywhere in the room, as long as you have a power outlet nearby. For most people, this opens up new options for hiding the sub or getting the best sound from it, as you don’t have to worry about running wires through walls or under baseboards once you’ve found the perfect spot. Pairing the sub to the transmitter was a breeze, and once connected, they never lost sync during any of my tests. Some listeners worry about the audio delay that a wireless system might introduce to the signal, but I noticed none at all. When I put the two subs next to each other—one hard-wired, the other wireless—and played the same signal to both, the bass seemed to play perfectly in sync. Conclusion In all my tests, as expected, placing the subs together produced the purest output. In fact, the pair of these damn near matched the audible and tactile impact of either the Hsu or the SVS when used alone. Were there limitations to what they could do? Sure—the Speedwoofer pair couldn’t go quite as deep as the big boys, especially when playing some organ samples that dip below 20 hertz. But, truthfully, it’s rare to find bass this deep, and given the difference in cost and size between the Speedwoofer and my reference subs, that’s a pretty reasonable trade-off. I should also note that, early on, one of my two subs developed an odd, high-pitched whine that was only audible following extended use and after I’d turned off the rest of my system. RSL responded immediately with a replacement, and traced the issue in my sample to an out-of-spec component in the feedback circuit that was causing some oscillations. Damn them gremlins! In any event, RSL stood behind the product, and as an online company, they offer a 30-day in-home trial for all their speakers, along with free shipping (both ways, if you aren’t satisfied). Of course, in the end, it’s the sound that counts—and in this regard, the Speedwoofer 10S is a surefire winner. On music, the bass is tight, with no overhang to speak of. Not once did I feel the sound was sloppy or inarticulate. In a room as large as mine, I would ideally want four Speedwoofer 10S subs—two in each sweet spot—to satisfy me. But in many smaller rooms, one sub would be more than adequate. And two would be even better to even out the bass response; that’s one hell of a bargain for $800. Until I hear something better, when someone asks me to recommend a budget sub under $500, this will be the first I’ll mention. And a sub under $1,000? I’ll recommend two of them.