Maybe it’s my Yankee roots showing, but Lexington, Kentucky isn’t the first place that pops into my head when I think about cutting-edge speakers. Yet it’s down there in Bluegrass Country where, for more than 30 years, Jim Thiel has been quietly pushing the envelope with his designs. The versatile SCS4 speaker and SS1 subwoofer are just the latest creations that demonstrate his often unconventional approach to handling vexing speaker-design problems.

The importance of time-aligning the drivers in a speaker has been known for decades. Yet the traditional solutions of mounting them on a sloping baffle or introducing phase compensation in the crossover will only work if both the speaker and the listener are positioned optimally. Move off-axis, or place the speaker either higher or lower than expected, and all of that careful driver alignment goes out the window. But if you mount the tweeter in the center of the woofer, the drivers will remain in perfect alignment, no matter what angle you listen from. This arrangement also brings the speaker much closer to the fundamental ideal of a point source, which helps to create a focused, spacious soundstage.

The SCS4, as its name suggests, is the fourth generation of Thiel’s Small Coherent Source (SCS) line. The twist with this latest version is that by having most of the components made in China (only the final product assembly and testing are done in Lexington), the SCS4’s $1,980-per-pair price undercuts that of the older, now-discontinued SCS3 by more than $800.

With a 61⁄2-inch metal-cone woofer incorporating a coaxially mounted 1-inch metal-dome tweeter, the SCS4 is designed to work equally well whether it’s positioned vertically on a stand, lying on its side as a center channel, or mounted up high as a surround speaker. Twin ports flanking the drivers continue the symmetrical layout, while a removable metal-mesh grille partially hides the drivers. A big, chunky pair of binding posts will accept just about any type of cable termination. (There’s no second set of binding posts for biwiring or biamping.) The cabinet has a solid-aluminum baffle for rigidity, while the sides and back use 1-inch-thick medium-density fiberboard with an especially attractive real-wood veneer in natural or dark cherry, or black ash.

The SCS4 itself has pretty satisfying bass extension. But testing the speaker in a stereo pair, we decided to include Thiel’s smallest subwoofer, the SS1, to check out how well the two models worked in tandem. The SS1, which omits most of the controls usually provided to blend a subwoofer with other speakers, is another example of the company’s lateral thinking. Rather than employing the generic crossover built into your surround processor, the SS1 is designed to be partnered with an external Thiel-designed crossover tuned specifically to the main speakers you want to mate it with. This eliminates most of the hit-or-miss tweaking required to achieve a seamless blend, although you do lose some basic controls, like a main subwoofer level adjustment.

Thiel offers two external crossovers: the active SmartSub Integrator and a passive model, the PX05. The Integrator lets you tune the settings for a wide variety of speakers, while the passive model comes in a dedicated version for whichever Thiel model you plan to use. To connect the passive crossover, you configure the main left and right outputs of your preamp/processor to a full-range (large) setting and run a parallel set of speaker cables from your amplifier to the crossover’s inputs. A line-level signal then runs from the unit to the subwoofer’s input. The sub also has a second line input with a level control, but Thiel recommends that you use this for your processor’s low-frequency effects (LFE) output. With 500 watts on tap to drive the long-excursion 10-inch metal cone, the SS1 packs quite a wallop.

Anyone who’s experimented with subwoofer positioning knows that a sub’s output level and frequency extension will vary depending on the distance between the sub and the room’s walls. As the sub is moved closer to each room boundary, its output increases, with a corner position delivering the maximum level. Rather than asking you to twiddle a volume control until things “sound right,” the SS1 has a pair of controls that let you dial in the distances of the two nearest walls. This alters both the sub’s level and response so that it will create a seamless blend with the main speakers.

SETUP

I first used two SCS4s alone and then added the SS1 to make a 2.1-channel system. With the SCS4s sitting on 24-inch-tall stands, I found that they could conjure up a massive soundstage with remarkable focus and precision almost regardless of where I placed them. After some experimentation, I ended up putting them about 2 1⁄2 feet from the side walls, but only about a foot from the front wall, as I found this helped to flesh out the midbass and the lower midrange.

The SS1 subwoofer’s boundary-distance controls worked pretty much as advertised. But I still achieved the best results with the sub in my usual position, close to the front wall and just to the inside of the left speaker.

MUSIC & MOVIE PERFORMANCE

Small speakers are often particularly good at imaging, but the SCS4s proved to be truly exceptional in this respect. Before I got around to any serious listening, I used the speakers for TV-watching to help break them in. At one point, I was watching practice for the Spanish Grand Prix early on a Friday morning when I heard some jerk outside my window racing up the street. I soon realized that the sound wasn’t coming from the next block, but all the way from Spain.

With bass that reaches down to a little below 50 Hz before dropping off, the SCS4s performed just fine without the SS1 sub. Rather than pumping up the midbass to give an illusion of deeper bass, the SCS4s are quite neutral through the midrange and down to their low-frequency rolloff. They also showed exceptional detail and transparency. For example, on “Song for Bassanio” from Jocelyn Pook’s soundtrack for The Merchant of Venice, the harp’s leading-edge attack, followed by the body of each note, combined with singer Ben Crawley’s clear, bell-like voice to deliver an astonishing sense of realism.

Firing up the SS1 filled in the system’s bottom octave seamlessly. Listening to Keith Richards’s bass line on “Words of Wonder” from his Main Offender solo album, the low end sounded tight, tuneful, and seemingly bottomless.

It was on subtle material that the SCS4’s movie sound came across. For instance, when watching Pan’s Labyrinth, I was impressed by how enveloping the sound was during the quiet forest scenes, considering I was using only a 2-channel setup. Then, when I decided to give the SS1 sub a home theater workout, the plane-crash scene in Flight of the Phoenix (2004) demonstrated that it could deliver the goods, although its emphasis was clearly more on tightness and dynamic punch than on bass quantity.

BOTTOM LINE

By using unconventional thinking and not shying away from complex manufacturing challenges for its SCS4, Thiel Audio has created a speaker that delivers exceptionally fine performance for the asking price, with an emphasis on sound quality over sound quantity. While adding the SS1 subwoofer is an expensive proposition, it rounds out the system and makes it a true full-range package that’s awfully hard for even this Yankee to criticize.

Frequency response (at 2 meters)
Front left/right: 96 Hz to 20 kHz ±4.8 dB
Subwoofer: 17 Hz to 163 Hz ±3.0 dB

Sensitivity (SPL at 1 meter with 2.8 volts of pink-noise input)
Front left/right: 90 dB

Impedance (minimum/nominal)
Front left/right: 3.4/4 ohm

Bass limits (lowest frequency and maximum SPL with limit of 10% distortion at 2 meters in a large room)
Front left/right: 40 Hz at 79 dB
Subwoofer: LFE 20 Hz at 83 dB

101 dB average SPL from 25 to 62 Hz
107 dB maximum SPL at 50 Hz
Bandwidth Uniformity 94%

All of the curves in the frequency-response graph are weighted to reflect how sound arrives at a listener’s ears with normal speaker placement. Measurements were made at a full 2 meters with the SCS4 on a 6-foot stand, which gives anechoic results to 200 Hz including full effects of cabinet diffraction and front panel reflections.

The SCS4 has falling low frequency response yet is still capable of providing low distortion sound pressure at 40 Hz. Directivity is tightly controlled, but basic response shows an octave-wide dip of 5 dB between 4 and 8 kHz and a 1.5-dB elevation between 500 and 1,500 Hz. Impedance is relatively low but shouldn’t present a problem to most electronics. The SS1 Smartsub Bass Limits were measured with it placed in the optimal corner of a 7,500-cubic-foot room. In a smaller room, users can expect 2 to 3 Hz deeper extension and up to 3 dB higher sound-pressure level (SPL). Bass Limits and frequency response were tested with both the LFE Input and the Passive Crossover.

The subwoofer has relatively extended low frequency extension at low sound pressure levels but its overall dynamics are just average. The Passive Crossover begins rolling off response by 12 dB per octave at 75 Hz, which reduces upper bandwidth artifacts by about 15 dB. The Sidewall response function simply increases output centered on 32 Hz by 1.9 dB at the 1.0 position, 3.4 dB at 1.5, 4.0 dB at 2.0, and 4.2 dB at 2.5. In a similar fashion, the Rear Wall function increases output over the whole subwoofer bandwidth by 2.2 dB at the 0.5 position, 3.6 dB at the 1.0, 4 dB at 1.5, and 4.2 dB at 2.0. Bass Limits were essentially identical using either the LFE Input or the Passive Crossover, although there was some difference in the frequency of maximum SPL (107 dB @ 32 Hz for Passive and 107 dB at 50 Hz for LFE) between the two inputs.

— Tom Nousaine