Thiel Owners

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.

Perhaps a little off subject here but I just stumbled upon a “new” product from McIntosh, the MA252 Hybrid Integrated amplifier.  

While it has been stated here that some Mc amps limit current - a definite drawback to those of us who’ve owned or own Thiels - this new thing puts out 100 watts into 8 ohms and 160 into 4;  nothing is mentioned in the literature regarding their famous/infamous autoformers.  Admittedly the piece is super cool looking as well. I suspect some constraints on current delivery because every other amp I’ve owned pretty much doubled down into 4 ohm loads. 

I mention this first because while I love the look of McIntosh I am not necessarily a fan.  I found their customer service to be extremely lacking when I had a minor issue with an MC275 Mark VI amp, and I truly found the 6700 receiver to be a disappointment. That being said, this little beauty goes for $3500 full retail - a veritable bargain in terms of McIntosh given the power rating and features.  Sheesh. 

It IS purty. 

Anyone here with McIntosh/Thiel?

PS:  This is by far and away the best thread in the A’gon forums.  The recent addition of Tom has been amazing.  Carry on!

I hasten to add that while the addition of Tom’s technical insight to Thiel excellence is equally fascinating and utterly insightful, I am a total ignoramus in this regard. Is it reassuring or disappointing that mere “consumers” can “get it” just by hearing them for the first time?

Hmmm....