Thiel Owners

Beetle - Stereophile's next publisher after Larry Archibald did not tolerate the editor producing content that put their major advertisers in dim light.
Andy - Design intent is 8' minimum distance. Farther away yields larger listening window.
Jon - power response is the energy dispersed through the whole room, which affects overall tonal balance, especially with phase coherent systems where reflected energy begins at the speaker as coherent waveforms.
Robert - I like the tenor of your observations. Keep it up.

As you all know, I am taking on the 3.5 after the 1.5. Both models are from the golden era and both sold more units to more loyal customers than any other products (the CS2 also fits that description, but its actualized design limitations and lack of parts takes it out.) My 1.5s are on their way. I'm looking for a pair of 3.5s to borrow or buy.

Tomthiel, PM sent.

Ok, let's try to keep the concepts clear. Time coherence is different from phase coherence and obtained differently. Thiel speakers are time coherent from an 8' distance as the drivers are set back in the baffle and the sound needs to travel some distance to fully integrate. In my measurements, I obtained time coherence within a few mm. at 8 ft among the drivers excluding room reflections by using freq dependent windowing.
Phase coherence in Thiel speakers is at best minimum phase, which means there is a phase shift that is measurable. The first order xo filters and the drivers have a minimum phase effect. This minimum phase effect can be reduced with dsp and other cancellation methods and linear phase can be approached above 100 hz. As Tom has warned, the preringing can become an audible problem so pick your imperfection.
Andy, if your point is that all speakers have some phase shift dependent on the frequency, there is argument. Thiel specifies it to be within 14 degrees which is considerably better then most alternatives. With dsp, the phase shift can be further improved if desired at the expense of potential preringing, although this effect can be mitigated to some degree with additional filters.

Rules - I like the term "time coincidence" as less confusing.Also note that the term of art 'minimum phase' includes the least possible, given all constraints. Note also that the phase lead vs lag in crossover regions does completely cancel each other to net zero. Bass tuning does not have that counteracting slope, so bass phase leads and lags with its resonant behavior. DSP can do stuff, no doubt, but with its own consequences.

Unsound - IF there were a boutique company refurbishing classic Thiel speakers, I think the CS2 would be a prime candidate. Let's spin a little: There were 5500 pairs made, built like little tanks, available for short money. One might probably insert CS2.2 drivers (as successors are developed) with necessary XO mods, or 3.5 tweeters and/or midranges. Solveable.  With today's tools, such as SpectraFoo and Klippel, a more robust anti-diffraction solution could be developed to replace the 1/2" MDF grille with perhaps a 1" equivalent like the CS1.5 AND the 04a rubber elastomer strips could be increased for very effective coupling. The CS2 has 6-9s coils and wire and styrene ultra bypasses around 1uF styrene bypasses for plenty of salvageable XO value. With my developing 'controlled wave-launch' baffle / grille technology, I am confident we could get class-leading performance.

The necessary ingredients are not in the design or technology departments, they are in the youthful vigor department - need of the right team to pull off the ongoing project. I'm working on that.

If you or anybody has a pair of CS2s, I hereby offer DIY coaching to hot-rod them.