Subwoofer Reviews

Even if Thiel hadn't given their new subwoofer line the slick name of SmartSub, I'd still say most subwoofers are stupid. Make that stoopid. Granted, I've had some good ones in the last few years, and that's no accident, since no reviewer would willingly submit to stoopidity. But, in an electronics marketplace where everyone's looking for a deal, the quality of the average sub that moves from a chain store into the home of some unsuspecting sap is dreadful. The average sub is a one-note gas box that loads up bass pitches with layers of spurious overtones and distortion. You needn't be a golden-eared audiophile to find it oppressive.

As Jim Thiel started work on the SmartSub series, three design imperatives sat on his drawing board. One problem he wanted to resolve was poor integration of subs and speakers. His solution, though not reviewed here, is a series of active and passive crossover products—if you're buying an all-Thiel system or integrating Thiel subs with other manufacturers' speakers, ask your custom installer about these.

Another problem Thiel identified was room interaction. This problem is showing up on lots of radar screens, if the growing number of room-equalized subs and receivers is any indication. However, full-spectrum room EQ sometimes creates more problems than it solves. Thiel focuses on bass-related problems—the area where most rooms are deficient. They diagnose them not as room resonances, which are hard to solve without a bulldozer, but as boundary-compensation problems, which are more predictable. The result is a pair of boundary-compensation controls, one for the side wall and one for the back wall.

Finally, Thiel zeroed in on what he described as output, distortion, and uniformity problems. In other words, most subs just can't carry a tune (or focus a detonation). Among their responses are an aluminum driver, large magnets, high-excursion surrounds, and a short voice coil operating in a long gap. The SmartSub SS1 is designed to deliver pitches, not to flap, rattle, or bleat.

Beneath the Veil
Thiel SmartSubs have a unique appearance. The pale metal driver is visible behind a translucent black metal grille and seems to hang in space. The red (off) or green (on) glowing LED is also positioned well behind the grille surface, making it appear like a little colored specter. My review sample came in the amberwood finish, a rich dark brown wood veneer, with rounded corners and gold screws securing the front panel.

The back panel includes RCA-type mono line-level inputs and outputs and two XLR jacks for use with the Thiel passive crossover and SmartSub Integrator. Absent is any crossover-frequency or phase control. As I mentioned above, Thiel prefers to handle these functions in a separate box, although the sub will work with the built-in crossover functions in the surround processor or receiver. If you have Thiel speakers, Thiel's passive crossover would tailor the sub to the speakers. The company also offers a SmartSub Integrator that can provide either augmentation or crossover with any other brand of speakers. I stuck with the 80-hertz crossover in my reference receiver, a Rotel RSX-1065. However, if I were using an all-Thiel speaker-and-sub array in a dedicated theater, I probably would opt otherwise.

There are three controls on the back panel. I blindly stumbled across the uniqueness of the volume control when I cranked it with a test tone, finding that it took a larger-than-usual percentage of volume range to fill my 19-by-14-foot room. I asked about it and got the following e-mail from Jim Thiel (you know you're in the big leagues when you get e-mail from Jim Thiel):

"You have done nothing wrong. I have intentionally made the functionality of the gain controls on our subwoofers a little different than most others. I have taken pains to make our control accurately logarithmic so as to make level setting more easily and accurately tunable. This means that a particular amount of turning, say 50 degrees, causes a particular amount of gain change, in this case 10 decibels, regardless of whether you are at the bottom or the top end of the control's range. By contrast, many subs' gain controls are linear instead of logarithmic; therefore, the control is far more sensitive at the low end of the range than at the high end.

"With these controls, the range from the 12 o'clock position to maximum makes only a 6-dB difference in level and, when set at 10:30, is only 10 dB below maximum. This makes it tricky to make a setting of, for instance, 15 dB below maximum. In comparison, our control covers a 25-dB range from 12:00 to maximum and the –10-dB setting is at 2:30. Your usual setting of one-third of max is about –10 dB of max on a linear control. The same –10 dB on our control is at about 2:30. I believe you will have enough gain available to achieve the level setting you desire." And, of course, I did.

Smart Woofin'
I experimented only casually with the SmartSub SS1's boundary-compensation controls, having already been satisfied enough with the bass response (rated down to 17 Hz with an LFE input) with both of them off. They're designed to correct both level increases and cancellations at certain frequencies. Until now, I've always assumed that my room had a standing wave—an acoustically magnified midbass hump—despite my almost religious avoidance of any placement near a corner or wall. With the SmartSub SS1 replacing my usual 12- and 8-inch subs, somehow the standing wave ceased to exist. Anyway, I pumped a 40-Hz tone into the sub at a low volume, sat on the floor next to the sub, tried the boundary compensators, and listened. I could hear the tone changing in character, as well as volume.

Low tones often signal excitement in movie soundtracks, but the quality of the tone affects the experience. In Kontroll, the story of beaten but unbowed ticket inspectors in the subway system of post-communist Budapest, the roar of the trains impressed me less than a synthesized tone that kept kicking the musical soundtrack into high gear. Instead of the blurred blare I'd expect from a brute-force, big-box sub, I heard a precise pitch. It didn't pound—it hummed threateningly, giving chase scenes a different emotional feel. It created less anxiety and more excitement.

Toy Story has a few great little subwoofer-borne moments, from the simple blam of a backyard firecracker to the bass parts of Randy Newman's cheerful score. The SmartSub SS1 didn't overplay any of them, and I appreciated that.

Tony Levin was the focus of my musical demos. What better way to celebrate first-class bass than with a first-class bassist? I've always loved his part in "On the Air," from Peter Gabriel's second album. As I ran through it again for the first time in years—on vinyl, no less—the familiar sound of Levin running like a panther in a pack of wolves was just as I'd remembered it, but I'd forgotten about his supple playing beneath the song's midsection. His bass lines swoop up and down a fair amount, and the SmartSub SS1's disciplined aluminum driver assisted by holding it all together, preventing the higher pitches from swelling out of proportion to the lower ones.

That gig helped get him a job in King Crimson. On Discipline, the first Levin-enhanced Crimson album, he switches on some tracks from bass guitar to Chapman Stick. The Stick is a long, hollow fret board that a musician taps rather than plucks. The shimmering solo Stick introduction to "Elephant Talk" is as good as anything anyone's ever played on the instrument, and, despite the absence of a Thiel crossover, it made the jump between the Thiel sub and my main speakers quite coherently. Just as impressive was the Stick's majestic growl on "The Sheltering Sky." Because the Stick's richly woody hollow-bodied harmonic signature is so different from that of a bass guitar, the SmartSub SS1 was influential here, as well. My cat endorsed this track by lying down in front of the sub.

Levin has made his fortune as session man to the stars, substituting sensitivity for anonymity. His touch transforms songs like "Watching the Wheels," from Double Fantasy by John Lennon and Yoko Ono, and again the Thiel sub maintained its proportion when those powerful hands moved momentarily from the lower strings to the higher ones.

Back to Unreal Reality
Occasionally, a product comes along and sweeps away all expectations, and the Thiel SmartSub SS1 did just that. It reminded me how crucial a player the subwoofer is in a home theater system. Even if you can't spend $2,900 (or more) for a subwoofer, you should still find yourself a Thiel dealer, audition the SmartSub SS1 or one of its larger brothers, and hear what genuinely deep-pitched and taut bass sounds like. You might find your expectations for bass performance slipping up a notch. Maybe the first step toward attaining the system of your dreams is to dream a better dream.

* Mark Fleischmann is the author of Practical Home Theater, available through www.quietriverpress.com.

Highlights
• Delivers clean, low pitches, and, in a sub, that's what it's all about
• Substitutes subtlety for brute force
• Corrects for some room-acoustic problems