Thiel CS3.7 Speaker System
Defining the Possibilities
Speakers sometimes remind me of cars. The marketing campaigns are built around uniqueness, but in a larger sense, most are far more similar than different. Most cars have combustion engines, four wheels that go around, and options that are more distinguished by the jargon that describes them than by their functionality. These days, many speakers are assembled from materials that are purchased from a handful of well-known source component companies. They often have much more in common with each other than people are led to believe.
Thiel’s philosophy on driver materials, crossover topology, and other key aspects of speaker design are far more unique. Thiel’s current flagship CS3.7 ($12,900 per pair) is the culmination of all that chief designer Jim Thiel learned in his 30 years of designing and building world-class speakers. I don’t know if any single area of this speaker’s technology is a true revolution. But I believe that the sum of these evolutionary steps adds up to a significant advance in the current state of the art in loudspeaker performance.
The Thiel Way
Thiel is now one of only two major companies that manufacture time- and phase-coherent speakers. In a conventional speaker, the tweeter and midrange typically reach the listener before the sound from the low-frequency drivers. Typically, speakers also use steep-slope crossovers, and some drivers operate in opposite polarity relative to one another. For example, instead of moving in and out in unison, the woofer moves out while the midrange moves in. Most manufacturers either don’t believe that time-domain issues are audible to most listeners, or they don’t like the tradeoffs that other areas of performance require to deal with them. Listeners who think that the time domain matters believe that time- and phase-coherent speakers can offer superior imaging and more natural instrumental timbre than conventional designs.
Thiel uses 6-decibel-peroctave first-order crossovers that minimize phase shift compared with steeper rolloffs. Thiel’s floorstanding speaker cabinets gently slope back, and a proprietary coaxial-mounted midrange/tweeter physically time-aligns the drivers’ output (all drivers are wired with the same polarity). The coincident driver technology frees the floorstanders from the narrow vertical listening window that’s found in some first-order, time-aligned designs (which some people call the “head in a vice” factor). First-order crossovers place a heavy demand on a loudspeaker’s drivers because the drivers must operate over broader frequency ranges. To meet its performance requirements, Thiel’s CS3.7 uses solely proprietary aluminum-diaphragm drivers, not off-the-shelf OEM drivers. More on those in a bit.
Thiel also employs underhung voice coils. To oversimplify, a speaker diaphragm moves when its voice coil is energized in a magnetic gap. Distortion can occur when a voice coil’s movements become nonlinear because of changes in the gap’s magnetic strength as the coil’s position in (or partially out of) that gap changes. Thiel believes that shorter or underhung coils in a longer magnetic gap maintain more uniform movement and therefore produce lower distortion and less dynamic compression.
The CS3.7: The Ultimate Thiel
In the simplest terms, the CS3.7 is a three-way, floorstanding speaker. The CS3.7’s cabinet is a gorgeous, domed tower that might best be described with artistic language. It doesn’t have any hard angles; the visual impression it makes is of curvature and grace. But there’s a close marriage between its form and its function. The shape minimizes edge diffraction, which can occur when sound waves leaving the drivers encounter the discontinuity between a cabinet edge and the open air of the listening room.
This often results in response anomalies and a defocusing of the soundstage. The curves in the domed head and the richly textured wood-veneered panels reduce parallel surfaces, which can minimize internal standing waves. The rigid aluminum front baffle stifles potential bending modes as the drivers move. The molded top feels so dead, I was surprised to learn it’s made of cast aluminum. It seems too dense and inert to be metal. Your knuckles will not win that contest. Although it’s a large floorstanding speaker, it’s gorgeous enough to put out in the room as industrial art. Maybe that’s a stretch, but I think they’re as pretty as speakers get.