Thiel SCS2 loudspeaker

"Its a dessert topping!"
"No, its a floor wax!"
"Dessert topping!"
"Floor wax!"
"Kids, don't argue—it's a dessert topping
and a floor wax!"

Twenty years later, this Saturday Night Live routine still rings true. Experience has taught me that very few products can do two things equally well. Remember those jaunty amphibicars that sported propellers on their rear decks, letting you drive them straight into the lake after a bracing spin along the back roads? Unfortunately, they could neither corner well nor handle even the slightest chop. As for Swiss Army Knives, well, I guess it's better to have a mediocre screwdriver/awl/magnifying glass/tweezers with you than none at all. And I've never seen a Veg-O-Matic in a professional kitchen, just mandolines, food processors, and knives.

So when a company like Thiel markets its SCS2 as a loudspeaker equally at home in high-end, music-only systems and high-end home theaters, experience tells me to expect considerable compromise in both applications. On the other hand, experience has also taught me that when it comes to Jim Thiel and company (footnote 1), one should expect extremely well-designed and well-built products that pretty much do what the firm says they will. Oh boy—a conundrum.

You can tell it's a Thiel...
Thiel has an enviable reputation in high-end audio. While the company's build quality and customer support have always been top-notch, much of that reputation stems from Jim Thiel's single-minded adherence to certain technical standards. All Thiel speakers, from the least-expensive Model CS.5 to the flagship Model CS6 and Model CS7, are floorstanding, with sloped baffles and first-order (6 dB/octave) crossovers to time-align the drivers. Sloped front baffles have become shorthand for "time-aligned" to the extent that many people assume any speaker with a slanting face is phase-and time-coherent.

In contrast, the SCS2 is a stand-mounted box enclosure with coaxial drivers, and it employs a second-order (12dB/octave) crossover—radical departures from Thiel tradition. However. these design choices represent clever solutions to maintaining phase, time, and amplitude coherence, the trinity that Jim Thiel has always held holy.

A floorstanding speaker eliminates one major variable from design consideration. Knowing the height—and, by extension, the angle—at which the speaker will be placed allows the designer to make certain assumptions concerning the path length of the signal. However, home theater's requirement for five channels makes the use of floor-standing speakers problematic at best. Thiel decided to employ coaxial drivers to ensure that no matter what height—or in which plane—the speaker is mounted, the drivers deliver the sound to the listener's ear at the same time.

Coaxial mounting, which places the tweeter in the throat of the midrange woofer driver's cone, is typically compromised by the reflection (and subsequent blurring) of the tweeter's energy off the midrange/woofer driver itself. This is also a typical shortcoming of horn-loaded speakers. Thiel claims to have gotten around this problem by designing a midrange/woofer with a short tube (into which the tweeter is inserted) that opens into a shallow-flare cone. In addition, the rubber surround is mounted on the rear of the mid/woof driver rather than on its face so its "roll" won't cause early reflections.

However, the tweeter's placement forces the midrange/woofer driver's geometry to be changed, so the mid/woof has less resonance control than a driver designed solely to reduce such resonances. Getting around this requires some canny design work, such as reinforcing the 6½" aluminum midrange/woofer cone with polystyrene backing. The driver's motor system employs an unusual short-coil/long-gap system that, according to Thiel, is capable of keeping the motor mechanism's inductance constant, even when the diaphragm is driven to extremes of excursion. The coil's short length and light weight dictate a more powerful magnet; Thiel has supplied two, with a combined weight of 1.4 lb.

Typical second-order crossovers are plagued by a 3dB rise in power response in the crossover region as well as treble lobing, which is exacerbated by changes in the height relationship between the tweeter and the ear. Thiel claims the coincidental mounting scheme used in the SCS2 eliminates the HF lobing outright, and the rise in power response from the crossover is mitigated by the reduction in power sensitivity caused by the midrange/woofer's increasing directivity as the frequency approaches the crossover region.

The result? A speaker whose accuracy in phase, time, and amplitude response can, despite its departure from company tradition, still be summed up in one word: Thiel.

This is also true of the cabinetwork. The rich veneer is matched on six sides and the boxes are dense and seemingly well-damped. They're certainly heavy; each speaker weighs in at 31 lb.

The SCS2 has two small ports on the baffle, flanking the centrally mounted drivers. These are "loaded" with foam plugs to increase their resistance. The plugs are removable, and Thiel encourages you to experiment. I did—and immediately stuffed the plugs back in. Without them, the speakers are under-damped and woolly, causing even moderate bass to become nimbly and undifferentiated. In addition, far too much detail is obscured with the plugs out. Perhaps the vise-like control exerted by an ultra high-end amp such as a Krell FPB 600 or a Mark Levinson No.33 would tell a different story, but I can't imagine that most people will employ those amps with these speakers. By all means, experiment—it's easy and it costs nothing—but based on my audition, leave the plugs in sounds real
If the SCS2 has a tonal signature at all, the speaker sounds a little dark and even a little closed-down on top. Thank goodness! By contrast, far too many speakers aimed at the home-theater market sound shouty and spitchy. The moment I installed five of the Thiels into my video system, I found myself relaxing into their soundfield as easily as a skin-temperature bath. No need to dip a toe in first or brace yourself for the plunge. The barrier between TV-land and reality was far less distinguishable than I had previously found it to be.

Footnote 1: Jim Thiel passed away in 2009.
Thiel Audio
Company no longer in existence (2018)