Thiel CS3.6 loudspeaker
The inherent tradeoffs in various designs make it difficult to find a loudspeaker that does everything well. This ideal loudspeaker may not quite reach the pinnacle of performance in individual areas offered by other designs, but its overriding virtue is that it comes close in all areas.
The Thiel CS3.6 is such a loudspeaker. It provides a very high level of overall musical performance and has no serious flaws. Although the CS3.6 may not have the imaging of the Ensemble PA-1 Reference, the bass extension and precise LF articulation of the Hales System Two Signature with a Muse Model 18 subwoofer, or the liquidity of the best electrostatics, it nevertheless approaches the best performance of each of these designs without their inherent sonic tradeoffs or cost. In addition, the CS3.6 is surprisingly inexpensive for the superb performance it offers.
The Thiel CS3.6 proves that you can have it all.
The CS3.6 is a medium-size floorstanding loudspeaker with the familiar Thiel sloping front baffle. In fact, the 3.6 looks very much like a smaller version of Thiel's flagship CS5, which was reviewed in June 1990.
The three-way CS3.6 uses a 10" woofer, a 4.5" midrange, and a 1" metal-dome tweeter. A 10" passive bass radiator extends the CS3.6's LF range, replacing the sealed-box loading of its predecessor, the CS3.5. (Unlike the 3.5, no LF equalization is used.) As with all Thiel loudspeakers, the crossover is a true acoustic first-order (6dB/octave) type. A black grille covers the drivers and curved baffle; the cabinet is available in a variety of wood veneers. (My review samples were finished in amberwood (footnote 1).) A single pair of five-way binding posts on the loudspeaker's bottom panel provides signal connection. Thiel believes that bi-wiring can cause detrimental interaction between the cable and loudspeaker, and therefore offers only a single input (footnote 2). Three carpet-piercing spikes—one in front, two in back—couple the CS3.6 to the floor.
All the drivers in the CS3.6 were designed by Jim Thiel and built to his specifications by Vifa in Denmark. The metal-dome tweeter, the same unit used in the CS5, features a long excursion (±1.5mm) and has a high resonant frequency (27kHz). This driver is crossed over at 3kHz to the 4.5" midrange driver, which features a unique design that is the subject of a patent application. The midrange's diaphragm is constructed of two cones of different shapes. The outer diaphragm has a greater flare, creating a pocket of air between it and the inner diaphragm. This structure is said to be stronger than a single diaphragm of the same weight. In addition, the lowest resonant frequency is higher than with a conventional diaphragm. The result is reportedly flatter frequency response and less energy storage in the diaphragm. The midrange also employs an innovative mechanical structure, including a short voice-coil in a long magnetic gap. This reduces non-linearity at high excursions caused by the voice-coil leaving the gap. The entire assembly is mounted in a cast magnesium basket.
Footnote 1: Thiel uses farmed wood veneers exclusively.
Footnote 2: Thiel also believes that a single run of high-quality cable is better than two runs of lesser cable. Further, they often don't hear a benefit when bi-wiring their loudspeakers. Finally, bi-wiring offers the potential of degrading the performance if users try bi-amping with amplifiers of different gains, or—perish the thought—if an external crossover is used.