Thiel Owners

Thielrules - it all depends. A very big deal is running out of power. The Adcom and Benchmark have overload LEDs. Listening at 95dB peaks at listening position, the Benchmark overloads consistently in stereo with one amp channel driving the woofer and the other the mid-tweeter. The bass amp can be bridged and its input sensitivity reduced to match the stereo upper amp. The upper stereo amp then becomes the overload limit, so it also must be used in bridged mono. Clipping is unacceptable. The Adcom at twice the power is better, but marginal on the mid-tweeter. It has no input sensitivity selector and therefore in stereo it cannot be easily gain-matched to the bridged woofer. So no go for tri-amping. Classe DR9 has similar power to AHB, so I assume it clips even though it doesn’t give LED proof. If you had 4 amps and could dedicate one to each woofer and one each to the two mid-tweeters, that is theoretically better than a single bridged amp to all three drivers, at twice the amp/cable expense. I am personally at peace with a Bridged Benchmark driving each channel with 3 separate cable runs or two runs: one to the woofer and another to the mid-tweeter.

To your question of best configuration - Because low impedance loads cause higher distortion in normal (non AHB) class A/B amps, I would prefer a stereo amp with one channel for the woofer and the other for the mid-tweeter. Those amps would need to be a few hundred watts minimum per channel into 4 ohms in order to stay clean. My amps in my space don’t deliver the goods satisfactorily in stereo mode.

Let’s do some history. As you know, the CS3 was set-up for bi-amping / bi-wiring. It separated the tweeter from the rest of the signal because the equalizer boosted the bass which included contribution from both the midrange and woofer, so they couldn’t be segregated to different amps. Audible improvement was gained by separating the tweeter. But the preponderance of users chose small SET or tube amps for the tweeter with no consistent way to gain-match the low frequency amp. Solving those variables would have required a different kind of dealer. Jim assessed that we didn’t have that expertise in the field to his satisfaction and removed the bi-amp /bi-wire option.

The scene is different today in that remaining Thiel users are likely to commit to getting it right or staying on the sidelines. It is tricky business, especially in the absence of clipping lights and with uncompressed and/or otherwise very dynamic music. Underpowering makes distortion and distortion fries drivers. Be careful.

tomthiel

Thank You for the history lesson. Keep up the excellent work via hot rod garage and studio. I can tell that you have made great strides while having fun.

Happy Listening!

JA - what a trip indeed. Circumstances have prevented progress in ways that many here assumed or wished for. I’m not yet discouraged; and I’m stirring the pot every day. My personal interest drives me to decipher some of the mysteries of Thiel and the idiosyncracies of its product performance. As you know, I have speculated that phase coherence allows the audio-brain to scrutinize sound differently than non phase coherent sound - as I formerly have written here. I beleve that, but many elements don’t neatly fit into that narrative, including the opinions of knowledgeable practitioners to the contrary. My search and questoning have taken unexpected turns.
An early assumption of low-hanging fruit was crossover component upgrade. Indeed good results were gotten there; similarly hookup wire and softening the wave launch surfaces on the baffle. But a derail occurred serendipitiously on a flight of fancy when I fantasized with an audio friend about some aha moments during early product development experiences in the 1970s. We identified the let-down when the ’hanging sculpture’ of the free-air crossover-in-development was nailed down and put in the cabinet. Magic went missing. Long story shortened, we re-created a bird’s nest crossover hanging in space. And, guess what - magic.

I have developed and tested some hypotheses and solutions and identified some obscure aspects of performance that migrate the musical experience from somewhat canned to substantially transparent. A relevant result is how ancillary equipment interacts with my speakers under test. Thiel fans have spent enormous time, effort and funds finding source equipment that works. And when it works, it works well. Shortened story: the outboard crossover has opened doors not only to better music, but to finding solutions to some pretty subtle problems, including broadening the range of acceptable drive components while increasing the level of detail, transparency and 'rightness'.

Anyhow, in moments of nostalgia for a company history that never was, I wonder about what we might have built if we had asked these questions and found these solutions in parallel with Jim’s relentless progress in the areas of his interest and expertise - where his innate comprehension of physics met his unique engineering ability to convert his best ideas into uniquely satisfying products. But, there is always more potential, isn’t there. What a trip finding some buried gems hiding in plain view within the platform he created.

@tomthiel, I wish I could share your faith in Thiel users getting amplification right. It seems that many seem to choose to ignore the basics. It’s not entirely their fault. I’ve seen different dealers offering what to me where incredulous demonstrations. Such as powering CS 3.6’s with 20  Watt intergrateds or CS 5’s with 50 Watt amps all the while resorting to their cheezy salesmanship gimmicks of grinning with crossed arms, nodding their heads up and down, tapping their foot,...all at barely audible listening levels. They were none too happy when I increased the volume to much, much less than typical listening levels. They would then lower the volume some and say that at these volumes the amps were sufficient, all the while the sound was of crunching distortion.
 Your points about radiation patterns and room placement were spot on. And let me clarify that even with DSP it would be preferable to work with a speaker that already was designed for a specific predictable placement rather than against it. Even if we’re not quite there yet, I firmly believe that DSP is the future. Though we may have to abandon previous notions to embrace the advantages of a new paradigm.
 The shared insights as to why the Thiel’s tend have low impedances was most interesting. In that there are still a few amplifiers to choose from that are up to the task justifies the gains in cohesion, ease of placement, and especially reducing lobbing effects.  I am continually impressed by the latest flat co-axils.
 Your comments about free standing cross-overs was most interesting. I seem to recall reading an article where Richard Vandersteen had the same “AhHa” moment with similar circumstances of free standing first order cross-overs. I never gave it much thought before. Perhaps vibrations, EMI, RFI, all, some combination, or none of the above? I’d be most interested in following your research on the matter. I’m still curious about your research on baffle reflections as well. Thanks so much for maintaining the research progress of our favored Thiel’s.
 

Unsound -
As you say, sufficient power is an absolute requirement. I may be naive, but I'm thinking that with good used equipment available at bargain prices, education would be fruitful because many folks could actually afford good to great solutions.
In addition to EMI and RFI from the interactions between the crossovers and the drivers, there is the proximity to metal driver frames and pressure fluxuations. A big deal is that cabinet vibrations necessitate every component being glued down to avoid microphonic and fatigue vibration. Plus the cabinet is a closed cavity, so heat generated by the crossover losses as well as the driver motors, wh heats up everything, changing the component values and circuit functions. It's not subtle. By outboarding I can dump crossover heat at the crossover and driver heat via heat sinks and thermal malpractice and compression are greatly reduced. each component can be mounted for maximum cooling.

The baffle stuff is quite intriguing - newly developed plate resonators to quiet and organize the launch waves. Coupling of driver motion to proper air waves is less than trivial as well is the chaos of early diffraction. Thiel paid lots of attention to that, but more attention is fruitful.

Here's an aside. I can play a woofer in a cabinet adjacent to its mate with the mid-tweeter. Same feed signal. Taking the woofer-induced vibrations out of the (upper) cabinet cleans up the high end considerably. Imagine that. I thought the CS2.2 cabinet was quite quiet, and it is by comparative standards. But better is better. I can remove the cabinet top and bottom to doctor the cabinet walls, newly accessible from taking the crossover outboard. Two versions under development. Underslung Crossover places the 3D network in a vibration-insulated and ventilated chamber under the cabinet while the Outboard Crossover version puts it in a free-standing enclosure about 3' behind and connected by an umbilical to the drivers.

To your point about the flat coaxes. Jim wanted coaxes from the very beginning for their solutions to placement and lobing problems. It took till the SCS in the late 80s to execute the coax and gradually get the outer cone more and more shallow to minimize the squak-effect. The flat-wave solves so many issues.