Thiel Owners

@tomthiel

Prof, as a technical note, that wavy driver behaves better than any of the previous cone drivers as well as supports the tweeter wave-form launch very nicely. Therefore the direct series crossover path is simpler than any previous Thiel driver. Jim had always corrected for slope anomalies in all the drivers, which puts additional components in the signal path. In the x.7 models, fewer components are required because the fundamental driver performance is so good. Part of what you hear is the thrill of nothingness.

Sorry I missed responding.

Thanks for that info. Very interesting.

It’s been a while since I read up on first order time/phase coherent crossovers, but I remember that one of the detriments can be some form of interference, or cancellation, I think between the tweeter and midrange driver if I remember. In any case, although I also really liked the old Meadowlark speakers (first order time/phase coherent) this cancellation is something I really noticed. Sit at just the right position or height and it was great. But move, especially vertically getting up from the chair and there was this weird hollowing and a sort of odd "shifting" of the sound, that turned me off. I forget whether I ever heard this from the Dunlavy designs.

I did perceive a very slight hollowing out of the midrange on the old Thiel CS6. But as I’ve said, to my ears this last generation coax by Jim nailed it. It’s just totally coherent, in a way almost no other box speaker I’ve heard can manage. No apparent suck-out or discontinuity, and from a large listening area as well, tonally.


In another forum thread I’ve been detailing an extensive list of speakers I’ve been demoing. Every time I come back to the Thiels they just show up the speakers I just heard in terms of utter coherency and disappearing as obvious forms of distortion or as sound sources. The truly amazing trick with the Thiels is that they not only "disappear" effortlessly as sound sources in a way most speakers are aiming for, but they don’t end up with the wispy sound that many "disappearing" speakers conjure. Instead the sonic images of the Thiels have such density. The impression I sometimes have is that the field in between my Thiels have been replaced by more speakers making sound!

hi Guys,  just added a few more pics. https://systems.audiogon.com/systems/7226Jeff asked about room size and i was really lucky with this room.  When i bought my home back in 1997,  i was single and i wanted to make sure that i had a great space for my listening and for the gear.  This room has a cathedral ceiling which eliminates a lot of issues with standing waves.  the wall to the right of the listening position is so far away that it really is not a factor at all.   the only parallel surfaces are the walls  behind the speakers and the listening position and they are about 15' apart. So the room is a nice big size and great for orchestral sound as those big Thiel's create a giant wall of sound.

Prof, you're right about the "hollowing effect". Phase cancellation is a central problem making first-order implementation very treacherous. The output of 2 combined drivers produces a lobe which cancels or augments output when the "listener" is not on the proper vertical axis to integrate the two signals correctly. The ideal way to implement phase coherence requires a true point source, as in the coincident upper drivers of more recent Thiel designs. Short of that coincident solution, the closer the driver spacing the better; notice the touching/clipped perimeters of Thiel mid-tweeters. Plus, the crossover frequency must be as low as possible because the beaming of the upper end of the larger (lower) driver interferes with and is discontinuous with the radiation pattern of the lower end of the upper (higher) driver, making for a room power response different from the on-axis driver response. To wit: Thiel upper crossovers are very low, lower than considered feasible by most; Thiel tweeters cross in around 3KHz. Such a bold XO frequency requires a tweeter that behaves all the way down, below 100 Hz. At these low frequencies there are bound to be resonances which would destroy the tweeter if not mitigated with notch filters, which are themselves costly. Broadband drivers are a design feat as well as a management challenge. Most experts, including those at the "New Thiel" deem the task "impossible".

You are correct: the coincident drivers do a better job than the older multi-driver solutions. But those multi-drivers are themselves extremely sophisticated and allow very low crossover points and both physical and electronic resonance control. Part of Thiel's low impedance (which we love to hate) is that each resonance correction lowers the system impedance, and the global system is really not serviceable until all resonances are effectively eliminated.

As I perform my XO upgrade investigations, I am continually surprised how good all these Thiel drivers are. As an example, the non-resonant bandwidth of the 3.6 midrange spans 7 octaves, with similarly stellar performance from every driver in the stable.  Part of my decision to reach back no farther than the CS2 2, is that previous drivers were merely modifications of off-the-shelf units from Dynaudio, Seas, and so forth. Newer drivers incorporate new sophisticated technologies toward success in first-order systems.

Back to the lab.