Thiel Owners


Guys-

I just scored a sweet pair of CS 2.4SE loudspeakers. Anyone else currently or previously owned this model?
Owners of the CS 2.4 or CS 2.7 are free to chime in as well. Thiel are excellent w/ both tubed or solid-state gear!

Keep me posted & Happy Listening!
jafant

Showing 50 responses by tomthiel

Cascade - I can't remember his or his shop's name, but I remember playing the first-tier Thiel speakers for him in his shop in 1977. He was complimentary and said he wished he were younger because a new world was unfolding for the young. He showed me his reflective speakers, which pre-dated Bose by many years. Bose had threatened him (cease and desist) and he responded that he would not sue to invalidate Bose's patent if Bose left him alone. And so it was.
Arvin - what a delightful lyrical moment to share, when things are 'just right'. Since such moments are so rare, I would appreciate, as might others, knowing the particulars of your rig, your room, and your reflections about how you arrived at this lovely place.
Hey guys - I would like to share a link that my daughter Dawn sent me for these times of darkness. Music feeds the soul. 
https://www.youtube.com/watch?v=ph1GU1qQ1zQ&feature=youtu.be
Arvin - thanks for sharing your synopsis. I'm curious how you landed on 30 - 32" seat height.
George - I had hoped you had gotten relief by now! I presently, since December, am struggling with similar symptoms. Reducing electromagnetic fields, especially microwave from wi-fi router and smart electric meter have helped. Brain electro-chemistry is wonderful when it works.
Shubert - Yes Dawn is wonderful. You may have "met" her virtually as Thiel's international sales manager from mid 90s to 2013 collapse.Masi- consider trying to stabilize the speaker on the stand. Three coins (back corners and front middle) serves to unitize the speaker with the base. Please report back. Also, small wire gauge can smear the bass. 
Arvin - FWIW, the design ear height is 3' and distance 10'. Closer than 10' means greater sensitivity to height. But, some folks prefer the more mellow presentation of lower listening heights.
Rob - please remind me what model speakers you have. The separation that you are describing was, in my day, standard practice. We always separated the twisted pairs to reduce capacitive coupling of the wire runs. Has anyone else noticed whether their runs were parallel or separated? I would like to figure out what's going on.
Rob - that sounds like someone replaced your original wire. Thiel wire was unmarked Straightwire (oxygen-free, 3 twists / inch, teflon jacket,etc.) . Did you buy the speakers second hand?
Rob - I can only speculate. Rob Gillum would know if your wiring was stock or not, since all the 2.7s were built by him in Lexington. I suggest that you query Rob and report back to us what you learn.
Andy - the baffle angles are similar because the design parameters are similar. But each takes its own particulars into consideration and yields a slightly different resultant angle. Notice that some models have slight wave-guides which differ from one driver and model to another, determined by target radiation pattern to equalize power response through the crossover. Also, distance between drivers makes a difference. Bottom line is whatever angle produces co-temporaneous arrival time at the design target (about 10' out x 3'up x 10° off axis). The CS2.2 has about 11° baffle tilt, others more and less.
Rob - I have also been unsuccessful contacting Rob G. Perhaps he'll re-emerge when the virus weakens. Re bankruptcy: I am in contact with the court, which seems to operate on Tennessee Time.
Unsound - you're right. Tennessee is decidedly the South, where things can move pretty slowly. Kentucky is "a place betwixt and between", with elements of many cultures and none in predominance. Lexington feels like a small cosmopolitan city, whereas Nashville feels like a southern town driven by country music.
Reubent - a general note: The 2.3 was the first generation of the passive coax. That coax and the woofer were bettered by the 2.4. But the crossover topologies are the same, and many of the values are same or similar. Eventual performance upgrades will apply to both models, and 2.4 drivers should become retrofittable to 2.3s with appropriate XO changes.
Andy - thanks for the article. I would mention that some of the statements are broad enough in nature that they don't apply to any specific loudspeaker in its use conditions. Of course, I mean Thiel. Toole's statement that off axis (vertical and horizontal) integration always suffers (paraphrase) is such a statement. Indeed it is true. But it is also true that a Thiel speaker 30° or 60° off axis is linear in both phase and amplitude. It is clearly true that the 1st order vertical axis lobing requires a single vertical listening position, ear height 3' up at 8' plus distance. But the up-tilting driver orientation and the resultant off-axis listening axis serve to create an average in-room phase and amplitude power response that is quite respectable, often bettering non-aligned counterparts.

As to the obvious dynamic range limitations due to large driver excursions - granted. First order slopes don't work well for stadium coverage or high-amplitude monitors. Driver overload is the Achilles Heel that we constantly fought and gradually improved. Drivers burn out or fatigue when asked to cover large frequency bands. But for livingroom hi fi, Thiel developed drivers that did well enough.

Despite the claim of near or no audibility of phase correctness in real playback rooms, Thiel demonstrated it over a long period of years to our complete satisfaction that phase coherence was audible enough to merit tackling all the hassles that came with it. And for some jujitsu, phase coherence made other anomalies much more obvious, requiring solutions to problems that would have remained invisible in normal phase-compromised systems.
Thanks for mentioning that. Those studies assume that anything that is scrambled can be descrambled with no deleterious artifacts. Part of my profession has been pointing out those "inaudible problems" in mixes and masters. I and my clients can hear the difference between a correct, unaltered take, vs one that has been "linearized", etc.

You know, a big part of the demise of "New Thiel" was that they chose to believe Toole, et al rather than construct their own comparisons. I offered to participate in those comparisons, and they said "no thanks"; they said knew what they were doing.
I agree about the 'special sound', as we have discussed here. My take focuses on the brain power that is freed up by not having to descramble the phase errors in other systems. I find the difference significant as do some others. "The Industry" (Toole et al) dismiss it in various ways as trivial.

I know for certain that many amp, cable and source practitioners and critics use Thiel as a tool to "see into" the source chain. I find that significant.
Nuzzi - I’m having a memory lapse even though it's only been 37 years. Please tell me if your CS3 equalizer is in a wood or metal case.
Thanks,Tom
Andy - it's good to point out not only the article's conclusion, but also other aspects such as why are they doing it, and what is significant to whom. As a whole, the professional community thinks that wire doesn't matter. Audiophile sensibilities and nuances are often not on their radar. If a factor doesn't hold up to ABX scrutiny, they dismiss it out of hand. I have developed a neurological model showing how ABX is irrelevant to nuance. And many top-drawer pro audio practitioners know that they must "live with" a component or solution for a week or two in order to "get it". That's a different world than ABX, where a snap judgement is made regarding whether X matches A or B. It is their gold standard, but I believe it is testing the judgement priorities of the subject rather than the subtle, complex merits of a component or solution.
sdl4 - Thank you. As you know, our undertaking was more heart and soul than the standard business model. We took pride in how long people used our speakers, sometimes for generations. Subtlety and nuance was a requirement, not a nicety.

I agree with your ABX comments and can add a couple more. You are not alone in "shutting down". I believe the judgement process is not only nearly impossible with the auditory chain, but actually misleading. I believe that several key factors are overlooked in the ABX model. Central among them is that the auditory processing response is closely linked to fight-flight / survival. We must immediately recognize the size, shape, weight, direction and speed of whatever made that noise in the woods. Sound is wired globally in our being. As such, the cognitive analysis of the sound is specifically shut down, especially in the right ear. Analysis is a luxury that the primal being can’t afford. So by applying ABX analysis and judgement, we are trying to short-circuit our primal experience of the sound (music).

I believe that the global direct experience in fact contains the information that we need as designers and want as music listeners - connection to the stream of energy. I still use a refinement of the evaluation process we developed in the 1970s at Thiel Audio. Here goes a story demonstration:
Some of you might remember Natasha, my young friend who listens to bats talk. Tasha happily has found love and moved out of town, which is great news for all concerned. But my ageing ears still want help. Good news is that I have found Marina Harris, a young singer-songwriter musician with outstanding natural hearing abilities. She is taking well to learning and relishing the listening that Tasha left behind. We have had two productive sessions, which served to underscore a very important element. That is Trust. Until she became secure that I was not "pulling a fast one" by repeating the musical segment with the same conditions, she was somewhat shy about proffering her opinions, and indeed could not really form them well. Once we established and she believed that I would always tell her the truth, and there would be no "fast ones", then she leaned into the task.
The procol goes like this:
Describe and agree on the protocol.
No idea what we’re testing for.
Play A while taking listening notes.Play B while taking listening notes(B has advantage of second hearing of same cut).Play an agreed part or all of A again - taking notes.Play same selection of B again - taking notes.Compare notes and discuss.Describe and discuss what we are testing for, such as doubling up the speaker cables, swapping an interconnect, speaker iterations, etc. including some description / speculation about how our notes relate to the systems under test.Then, armed with this experience and learning:Repeat A / B, A / B and discuss again.
Note that by design at no time is a commitment required, and at no time can the listener be "caught out". ABXers consider that a cop-out. I consider it a necessity and my experience is that a valid session is always (and must be) replicable after scrambling A and B double blind. In other words, a third party can re-assign channels and substitute different audition material before the subsequent validation test.

This protocol produces a wealth of information from many aspects including, technical, performance, emotional, memory/evocative, etc. I use it in evaluating recording sessions, mixes and masters as well as equipment and rooms. It makes ABX seem thin and poor.

As a historical note, in the early 80s, when developing the CS3, we had developed a relationship with the University of Kentucky. They were willing to collaborate with us using medical, music and engineering students, if we were willing to use the ABX protocol. We did some trial runs, which served only to muddy the waters, and provided little if any productive information. Therefore, we opted out. I am convinced that if we had gone down their path, we would have ceased refining our multi-faceted development process. Plus we didn't have the time to indulge their ABX plan unless it provided valuable information for us, which it did not.

I hope you’re all enjoying your opportunity for seclusion. I’m getting more time in the studio since the phone stopped ringing.Tom




Rob - for clarification, my experiment at your suggestion was to double-up my Morrow SP-4 cables. Each cable contained its traditional + and -, and that cable was paralleled with an identical + and - as in normal bi-wire, but with single pair of amp and speaker terminals.

Your new concoction makes each entire cable either + or -. I compared this morning and must say that I am intrigued. I will listen more and defer any comments  until after Beetle has commented. I also encourage others to make this comparison because it raises many questions. It can be carried out at any cable quality, as long as you can conjure 4 identical cable runs. I would love to hear comments from cable skeptics.

Fascinating. So much to learn, so little time.
JA - Covid-19 is not rearing its head badly here yet. The NH governor took swift, decisive action and people are being very cautious. I hope all of you do well. How's it down south?
It might add value to describe my approach to the cable differences. First, a disclaimer. I do not claim to know how the variables of cable interact with each other. I am apprised of the textbook basics of capacitance blocking low frequencies, inductance rolling of highs, etc. And I know that dielectric absorption matters and a few conversational recommendations. And I also know that those things don't explain for me, and it seems for many very expert engineers, what we hear.

Today is not about what I think I might be hearing. It's about my setup, which might provide food for thought or questions, especially from more knowledgeable folks. Here goes. One corner of my studio has a corner baffle with floor-level bass vent into other space. This corner measures well. My amps are overhead with multiple jacks and knife switches for setting up quick-change tests. My chair is about 6' from the V point of the L-shaped room, so there is little reflection from behind. The mic is right in front of me, so it hears about what I hear. For this test, two CS2.2 are side-by side, one meter from the diagonal baffle behind them. My chair is 2.5M (100") back and the mic is 2M - I get usable measurements and hearing in this setup. In this case I have wired speaker A with 2 runs of Straightwire Octave II in standard configuration: + and - in each cable. So there are 4 wires running in 2 cables, each containing a + and a -.
The B speaker has the same cables, but one cable is ++ and the other is --. Those cables are separated by more than 12" in configuration B, and they are taped side-by side in configuration C. Today I am listening to Rory Block's "I'm Every Woman" which has enough of everything I need.

I also run FuzzMeasure through the system to document A, B and C. More coming after lunch.


If we had the luxury of the Great Symposium where we could hash these issues out with George Cardas, Bill Low Audiouest, Steve Straightwire and various astrophysicists of our choice, we could learn a lot. But in real life, we must make whatever progress we can make, learning from experience and limited knowledge and paying attention to lots of leads.

Here's a memory of such a lead. The CS5 had a huge crossover that included 2 huge bucket brigade delays in addition to 4 crossovers for the 5 drivers, which had huge magnets. Talk about a pot of soup. We used our usual solid 18 gauge tight twist in teflon. Jim always included the speaker wire runs in his calculations and tests. In other words, those wire runs add resistance, inductance and capacitance to the crossover circuits, and he included that in his design / execution work. OK. In final (4 months long!) listening tests, those crossovers came in and out lots of times. The workhorse pair used straight single wires from the XO terminals to a terminal block mounted on the side of the cabinet. Eventually the twisted driver runs were hooked directly to the XO, and there was "a sound" that couldn't be accounted for in electrical terms nor in concept engineering terms. We chose the final 9" to 12", depending on which driver,  to be left untwisted. Something about how the wire-fields were interacting with the "pot of soup" made that configuration sound better. It is possible that Jim gained additional knowledge as time went on, but at that time none of us nor anything we could learn could explain much of anything about the heard phenomenon.

We may be in a similar situation with these cable runs. I ran tests on A, B and C as described above. All the tests in my kit - to see if there were changes introduced by the different configurations. I can't detect any. So far I have listened to Morrow SP-4 and Straightwire Octave II. Both exhibit similar differences. Both are sophisticated cables. I have not yet tried my ProCo (Beldenesque) HiPure 4-conductor "normal" stranded cables. What I learned from the SW, is that the 3 configurations measure as "identical". There are no measured differences that I can identify to account for the heard differences. So, whoever goes comparing, you can dismiss the potential cause of measurable frequency response changes, or impulse or phase changes. It's something else.

As an end user, Rob can choose whichever he likes better. Fair enough. As a designer, I must pursue understanding that might be applied in the internal wiring as well as fodder for this user mill's advancement.

I'll be calling Steven Hill and George Cardas to pick some brains. I'll be very interested in what Beetle reports. Any other input is also much appreciated.
Rob, Thiel Audio would have used such information, but Jim died in 2009. His active projects after the 3.7 were the 3.7b (Chinese XO), the SCS4 and CS2.4SE, and the CS7.3 which was not developed. He didn't work on the CS2.7. 
Beetle - No, No I didn’t mean it!JA - Ray is a good idea.All - I continued my comparisons re cabling and noticed a deep bass rumble / congestion with the C arrangement: ++ and --, taped together for close parallel run. Rather than side by side, I put each speaker individually against the corner fill and compared measurements. C had a 10dB rise below 30Hz to the cut-off at 10Hz compared to B, which continued its normal bass rolloff. I confirmed with listening in that corner position. Now, a bass reflex cabinet is rolling off at 24db/octave. There must be powerful resonant mojo in that cable configuration to produce that much deep bass. Anyhow, the B - separated runs - sounds cleaner and more articulate.I’ll repeat this morning and scratch my head.
Rob - I am a sucker for tracking down stuff I don't understand. I think I will try taping A and A to see what happens. My interest stems from the tendency to replace a wire with a better wire and like it better. Often throwing money at a problem makes it better, even if just in our own minds. I do know that Jim took internal wiring very seriously and tweaked it for years. I don't want to blunder into undoing any of his work by substituting a different solution. On the other side of that coin, I think it highly likely that Beetle, you and others have bettered the outcome. I must quantify such betterments, assess potential pitfalls and decide how to proceed. The puzzle is eternal.
Beetle - crossing at the amp has fewer consequences than parallel. More distance is better, but not by a lot due to inverse square law of distance.

Andy - I have previously addressed the single input thinggy. Thiel wanted to side-step the pitfalls involved, both in unmatched cables and the illusion that the added cable expense was needed for designed performance. I am adding a second input pair with good copper shorting plates.
Unsound - yep. The ’why not’ gets slimmer once the ’single’ barrier has been broken. And your suggestion puts the user in the driver’s seat. If we’re thinking a la carte, then the extra cost of a good pair of posts becomes user selected. I am reminded of the CS3, which split the tweeter from the other two combined drivers. That decision was partly due to the equalizer boosted bass with contributions from both the woofer and midrange drivers. But there was also input from Nelson Pass for the advantages of a very sweet class A tweeter amp. Jim prototyped such an amp with gain control to match any full range amp. Separate amps would allow low-level crossovers, before power amp stage where ultra-quality components would cost far less. Plus each cable set would be free from intermodulation from the other bands. No end to the possibilities.

Your idea brings to mind something we wrestled with at that time, an 'ultra' line with even more lovely cabinets, special veneers, hand scraped and rubbed finishes and whatever level of exquisite sound quality that might be imagined. The idea didn’t go very far for lots of reasons, but in the early 80s Thiel had very strong and enthusiastic support from reviewers, the editorial press, dealers and consumers. I suspect a market was there, and Thiel could have addressed it. One very tricky part would be how to keep the ’normal’ line from seeming like a poor cousin to the ultra line.

At that time Thiel was being courted by Mark Levinson and other expensive brands to develop and build such speakers under their brands. Thiel didn’t have the scope or desire for such undertakings. During my 20 years, and probably onward, Thiel grew at a maximum pace. We couldn’t have grown more if we had wanted to, which we really didn’t. We wanted to do a good job supplying our niche, and affordability was central to that self-image.
Yep - the electrical aspects of the stock twisted pairs is burned into the design. If wire configuration is changed, then xo changes will be required to compensate.
Hello folks. I've been scanning this thread as time permits but life is short. By way of introduction, I was a founding partner and for the first 20 years was the director of manufacturing of Thiel Audio. I was intimately involved in all aspects of product development and company-building. I hope to contribute some elements of perspective to this conversation, especially where speculation lacks sufficient knowledge.

I want to clarify Jim's attitude about passive parts quality. From the beginning in the mid 1970s, we became very aware of the subtle but significant improvements via better parts. In fact we were an early innovator re film caps and bypassing with small values of better caps. We introduced long-crystal, six nines wire for our air-core inductors to the industry. I'll spare the details, but Thiel understood that landscape before it was considered an issue. So, the speculation that Jim was strictly a measurement-guy is incorrect. The reason for less-than-best caps is that they can be cost-prohibitive for highest value per cost engineering.Thiel was always about finding the optimum point on the cost-performance slope so that real music lovers could afford our products.

Regarding the measurement tells all idea, we found our way via intense, systematic, long-term music-listening and then Jim engineered solutions that had to also pass scientific rigor. Once the understanding about any particular issue was in place, the measurements contained the information; and the chosen solution was always closer to the scientific optimum. We could see the results of our work in the measurement data, but the converse was not true: the improvements could not be made predictively via the data. By the way, Jim designed and built test equipment that was way beyond what was being used for the purpose.

On the issue of hot-rodding existing Thiel products. I wholeheartedly recommend it, knowing the value / cost parameters of Thiel products. Rob hopes to offer upgrade services. Madisound is also a resource. I upgraded my (original 1989 prototype) CS2.2s with boutique signal-path caps. Wow. Keep in mind that the original caps were all carefully chosen for type, geometry and manufacturer and often bypassed by even higher grade capa. So, don't indiscriminately change everything. The best bang for your buck is in tweeter feeds. Note that (real) Thiel inductors are air-core (contrary to someone's post) and the wire is as good as it gets. Resistors are likewise selected to be very good. But improvement can be made there also. Solder is silver/tin, which requires more care than usual. Hookup wire is six nines with teflon jacket and proper twist density.

Another thread here has been the electrical vs acoustic first-order crossover. By "acoustic" Thiel simply means the net resultant system performance. That final slope of that driver in that cabinet with that insulation, wire lengths and other factors including eddy-currents, reflections, propagation distortions and other factors . . . all end up on a slope of 6 db per octave to produce a phase and time coherent crossover that passes a square wave and/or impulse - intact right through the crossover frequency. That fact of coherence allows the ear-brain to consider that signal as real rather than as puzzle to be interpreted in the fore-brain. I mention that because small system changes are more easily heard in a first-order system than in any other system. So, when you change caps, resistors and the like, be careful not to inadvertently change system parameters. As an example, some types of resistors exhibit different induction and capacitance than other types. Some capacitors exhibit different induction . . . and so forth . . . everything matters.

Take care with your upgrades and I believe you'll be amazed at the improvements in rendition of subtle detail.

To close, be assured that Rob is doing his best to ensure the best care of all you supporters who kept this little company producing these extraordinary products for all these years.

Best regards, Tom Thiel  
I apologize in advance for what might be spotty participation. I travel and am highly involved in multiple projects.  But on the other hand, I do appreciate this forum and the enthusiastic involvement you folks have in the sport.

Regarding phase / time integration: An optimum axis exists where the drivers' acoustic centers are equidistant from the ear. Thiel designs for a 38" ear height as a seated average. Since the objective is a point source, the coaxial / coincident upper range driver obviates time arrival problems there. But the woofer is distant in order to place it on the sloped baffle at the proper distance from the average-height ear. The closer you get, distance error becomes more likely, but not necessarily so. (a three or more element system would have only one solution, but this 3-way with the coincident mid-tweeter makes it a 2-element system with multiple solutions.)  A measurement from your ear to the tweeter and the dust-cap of the woofer should be identical. If not, adjust your ear height  or speaker tilt accordingly. Pink noise is also a helpful tool in finding the sweet spot.

Subwoofer placement presents many problems; room mode minimization competes with other listening factors. A previous question about the "below 80Hz" crossover frequency is germane. The lower the frequency, the less the ear-brain specifies position. Bass waves are long, so bass is everywhere. However, the real-world crossover slope allows the subwoofer to contribute into the mid and upper bass where the ear-brain does specify position. I like Thiel's augment mode where the crossover to the woofer is first order and only the subwoofer is higher order. By the way, that is tuned as a 4th order Linkwitz-Riley. (Note: this stuff is from long-ago memory and I am not fact-checking as I write.)  I use a stereo pair of Thiel SmartSubs and place them at the proper ear distance for best integration and use the room-boundary controls to adjust for early wall reflections. I find the system amazingly accurate and effective and the result surpasses any other system of which I am aware. Keep in mind that when conventional subwoofer integration is employed, the frequency response at the listener position is optimized at the expense of all other positions in the room. Therefore the average power response in the room is wrong and the resultant sound is artificial. Remember that the ear-brain is synthetic, we create or fabricate the sound we are hearing and when the sound doesn't match the room, that is unsettling. Bass is especially subject to needing "psychoacoustic rightness" in order to be emotionally gratifying. Note, I realize I am skating into my personal research and conclusions with insufficient contextualization, but I want to get the concepts on the table for your edification.

Bottom line: I think that bass-generation position is very important and I position my subwoofers where they are distance-correct and let any room problems be addressed via Thiel's sophisticated distance controls or room treatment. Remember the magic of corner-positioned bass dumps. Pressure develops at the (normal) 8 corners of the room. Make holes / dumps there and room problems are drastically reduced. (Open a door or window, install a vent, and so forth.)

Regarding music: I was a singer-songwriter and recordist, which partially led to the formation of Thiel Audio. I prefer acoustic, authentic, ethnic-folk music with stellar production values. I appreciate all forms of music. I like live or live in the studio recordings and find the current multi-miced and processed amalgums to be generally uninvolving and unsatisfactory, no matter how well done. Our early research that led to our phase coherent products was validated by the high level of emotional connection to the music when played via a coherent solution as opposed to the normal, hi-fi, higher-order crossover solutions. Long story, short answer: Coherent Sources are perceived as real.

I presently design and build acoustic guitars with related research, teaching and mentoring. Tonewood creation and sales are also part of my offering. I am presently creating a high-resolution record-playback system to record and store sound samples of guitars under development for direct A-B comparison via selective playback exactly where recorded. Earthworks mics and preamps, yet unchosen ADA conversion, REAPER DAW on Mac, Classé DR-6 pre and pair of DR-9 power amps (hot-rodded) with Sennheiser HD800S open and Beyerdynamic 770 closed headphones, all six 9s solid wire configured in house. The recording rig will be used mobile and in this multi-purpose studio. We build guitars in the recording-listening space.

That's about all for now. Back to work.
Here's a thought from the archives about "bright Thiels". RonKent's observation re same system, different speakers . . . Within very close limits, the models represent nearly identical frequency response performance. But Ron's experience of increasing "smoothness" is correct. All sorts of hash accumulates in the high frequencies and coherent speakers permit the ear-brain to perceive that hash considerably more audibly than other speakers. I perviously alluded to this phenomenon . . . it is a deep and interesting arena where future psychoacoustic research will validate Thiel's approach (IMHO). Anyhow, the original CS2 is the last model that used fundamentally off-the-shelf drivers which we tweeked in-house to suit our purposes. That Audax soft-dome tweeter was highly regarded, but had far less sophistication and produced more "sonic edge" than than any future Thiel-designed driver. Similarly, many audiophiles removed the CS2 grille (just because.) That grille frame contained the anti-diffraction machining and the fabric tamed the resonant peak of the dome. Furthermore I might venture a guess that Ron may have upgraded cables and/or other equipment as he upgraded his series 2 speakers.

From the beginning Thiel chose to produce the most authentic reproducer of the signal supplied to the inputs. Most companies pull some punches to make the listening experience more palatable. I find it instructive that in all the years of exhibiting around the world with all manner of associated equipment, I never experienced these artifacts of "brightness, hardness", etc. We and our various associates vetted ancillary equipment against both technical and listening tests.
I am interested in what caps are chosen by upgraders among you. I am presently researching my cap upgrades for the two pair of PowerPoint 1.2s I use for my mixing and mastering monitors, due to space limitations. That 6"x 1" coaxial is the same as the SCS 4. And in that near-zero diffraction ceiling-mount sealed cabinet, their performance is surprising. Mine are late, Chinese-made, printed circuit, non Acousta-coil, etc. with lots of room for improvement. I have high hopes for the upgrades on outboard point-to-point boards. Note that the 2.4 SE only replaced two Solen mylar feed caps with Clarity SAs. Today there are much better caps available today from Clarity, Mundorf and other brands. My personal experience (via consulting for other brands) is that the upper end of the woofer circuit is sonically important, especially with Thiel's first order filters, and that budget is the only limitation to sonic improvement in a high-resolution system. I'll keep you informed as I finalize and test my conversion. I suspect that hot-rodded Thiels of many models might make beetle's list. My apology for using the "B" word regarding caps. I meant esoteric high performance, not snobbery.

Speaking of Esoteric. A real eye-opener for me was hearing the newly introduced CS3s at the 1983 CES, paired with Esoteric Audio Research (EAR) tube amps. Astounding 3-D performance. Jim didn't like the under-damped bass that is hard to overcome with tube designs, especially with the increased demands of the CS3 equalizer. I love big tube amps with well-damped bass, or side-stepping the issue with a powered subwoofer. Of course there is the cost to consider.
Unsound - later today (or tomorrow) I hope to directly compare some wire of interest to you.
• Original OCOS / double runs• Straightwire Octave II which Steven Hill recommended as their best bang for buck cable• Morrow SP-4 copper / double runs
I have been using the Morrow and Straightwire, so I have a baseline for the OCOS.
Beetlemania is right that the ClarityCaps were only used in the coax feed for the 2.4SEs.  Jim and Gary and others performed extensive listening tests to isolate those 2 tweeter caps as the most critical improvements, and I am not second-guessing their business decision. That driver is significant in not having an electrical crossover for the tweeter, which is the most critical driver for cap quality. So, two feed caps effectively handled the midrange and tweeter. However, I am suggesting that further although more subtle improvements will surface when feeding the woofer with higher-performance caps . I am testing that prediction with my PowerPoints and may then modify my CS2.2s as the experiment dictates. 

Prof, passive parts upgrade improvements are hard to describe without sounding cliché. You will hear them in terms of naturalness, ease, fluidity, three-dimensionality and such qualitative adjectives. The improvements relate to dielectric absorption and are therefore in the time domain and result in slight smear and sonic residue.  I have performed such upgrades in speakers, amps and preamps, but not yet on my own well-known speakers in my own well-known system. 

I should add that the most obvious crossover upgrade I can remember is when we identified a need and found great copper in the development of the 03 in the late 1970s. There was no going back from that discovery. All coils and internal wire have been six nines, long crystal, etc. since then. We were the industry wire pioneers as far as I know. 
Sorry for the sloppy writing. I meant that the problems of inferior caps cause those distortions which are mitigated and clarified by more nearly perfect capacitors. 
TT
Oops, that response was for for unsound. From very early-on, perhaps the beginning, but at least the CS3 in 1983, Jim built zobels into the crossovers to stabilize the impedance load for amps. 
Pops - I don't have their Zobels. These OCOS cables have been with me since about 1990 when Thiel Audio "upgraded" to more something better. I believe it was Straightwire coax prototypes with similar geometry but better wire and dielectrics. I don't know whether SW still makes such cables. Over the years, using these OCOS in many situations, with many amps and speakers, they seem to stay neutral however they're used. Coax cable claims such characteristics. I have double pairs, but have had to hotrod the termination plugs with hard-wired ends. The ends break tabs, etc. and Sumiko no longer services them.
As a point of clarification, the CS2.4 tweeter feed has a 13mF PP in parallel with a 1mF Styrene to total 14mF, plus a 27mF PP with a 1mF S > 28mF total. I believe those even-integer values are available on the market.
beetle, it is likely that my CS2.2 cabinet design persisted to the CS2.4. If so, the enclosure bottom dismounts with screws from the bottom of the base to expose the crossover mounted on the inside of the base.
Guys, it's official that Rob Gillum has bought the service business from the Nashville owners of Thiel Audio, who are officially closing. Rob needs a couple of weeks to transition. He will have a new phone number and email address which he will post on this forum when he's back in the saddle.

Rob has been with Thiel since 1988 and has done nearly every job during that time. As you have experienced, he is a first-rate guy on all fronts, and he will appreciate any and all support that you can send his way. He intends to develop upgrade kits for any Thiel products to meet demand. Other original Thiel operatives and myself intend to pitch in to help him succeed.

Thank you all for your ongoing enthusiastic support of the Thiel brand.
sdecker et al, it is important to keep the cap values consistent with the original design. Judging by your description, the 1uF bypass caps were left in place and the main caps replaced with SAs, thus keeping the total paralleled capacitance correct. Regarding outboard crossovers, tread lightly. The crossover network works in an environment of the woofer magnetic field and the close proximity between various crossover inductors as well as vibration. When finalizing a model, some values were sometimes slightly tweeked to adjust for that in-cabinet environment compared to the open-air development environment. Sharing our experiences will help in learning this subtle landscape without the resources of a full development lab.

I am hot-rodding my PowerPoint 1.2s for studio monitors and must outboard the crossovers due to insufficient interior cabinet volume for the larger upgrade parts. I expect performance improvements from the combination of outboard mounting, greater proximity isolation (increased footprint), lack of woofer EM field and vibrations, point to point wiring, six nines hookup and choke wire . . . in addition to the higher-performance caps. Note, my PowerPoints are late-date manufacture from China. Although care was taken to spec first-rate parts, I can't know if the Chinese manufacturer used parts as sophisticated as Thiel in-house manufacture did.  I am upgrading with all original-Thiel parts and techniques. I will journal my results by comparing an unmodified pair with the modified pair in the same system.
I am not expert on what manufacturing moved to China and when; I have not been involved with the company since the mid 1990s. At that time the only off-shore components were some European electronic components. My general impression is that the hi-fi music products were always assembled in Lexington, although some parts, including drivers, were made partly or wholly in China. Home theater products were made at increasing levels in China, more so after Jim's death in 2009. Testing and QC remained in Lexington throughout. These are my opinions developed from various conversations, but are subject to correction.

I know from other involvements that it has become increasingly difficult to impossible to source many sophisticated components from North America / Europe due to changing market conditions.
It seems the site ate my detailed response.
In summary, just be careful because you don't know what you don't know. Thiel (Lexington) parts selection was rigorous and knowledge-based. Don't assume you can get a whole-system improvement by throwing more money at it. Compare notes among ourselves. I will share what I find out in my upgrade efforts.

Jim chose ClarityCaps SAs at that time, all things considered. CC replaced those with ESAs and now CSA's. I'll look closely at them. Mundorf recommendation came from Madisound based on wide comparative evaluation and user feedback.  Dave Garretson is known among you as a trusted source of good information. Use him. Be very careful of unknown recommenders. Rob Gillum will make knowledge-based decisions.

I will share the results of my PowerPoint 1.2 upgrade as it develops. Can photos be posted on this forum?
fitter468 re PowerPlanes - I have never lived with PowerPlanes, but I have and use PowerPoint 1.2s, which are the same PowerDriver 6.5"x 1" coax. Pretty special. The woofer has dual front and rear cones with a styrene filler core, and the tweeter is the same as the 3.7, etc. I imagine that your PPlanes will have similar performance to the PPoints, which I call excellent by any measure. FWIW, I revised my installation to now have acoustic ceiling panel on the previous 1.5" felted foam roofing insulation, on 1/2" drywall on 2x6 studs, braced at their mid-point. It's a structurally rigid wall with progressively absorbent skin.

I now have a SS2 in the wall under the left speaker and hope to get my SS1 repaired for a right-channel matching subwoofer. The PPoint is -3dB at 80Hz with sealed box 12dB/ octave and the Thiel SSub Passive XO matches that transition for as seamless a hand-off as I've heard.

As you might have guessed by now, my installation is weird. My PPs are in a corner at 3' each from the corner with their tails near the ceiling. ( I couldn't get 4' due to physical constraints.) Their 45° vertical and horizontal launch from the symmetrical corner fills the room with little to no modes. A couple of potential problems were addressed. The vertical corner between them is filled with a 16" wide 45° floor to ceiling baffle. At the ceiling, there is a corner baffle at 45° to the ceiling for mounting drivers under test. The ceiling and floor behind the corner baffle have holes to vent back-pressure to the attic above and workshop below. That corner triangular void  is insulated in the back 2 walls, plus acoustic cellulose on the back of the plywood baffle. I can measure no resonances in it. The bottom 2' has no plywood front face, but rather solely a piece of acoustic tile to dump the 3-plane floor-corner walls bass pressure into the insulated corner void and leak into the attic above and the workshop below. The room ceiling is finished in drywall. Both exterior walls are finished with acoustic tile on foam board and the interior finish on the 45° baffle is F11 wool felt on acoustic tile. This setup is my third (and final!) iteration of the idea of a quiet corner. I can test drivers or musical instruments or recorded voice / ensemble in this corner and play it back in the same environment. Very revealing of what's going on. I like it.

The PowerPoints (and probably your PowerPlanes) produce a very solid, dense image with no discernible room or cabinet edge effects. Since they take no floor space, and present wonderful sound into the whole room and beyond, I would be happy with them as my sole playback source. Let us know how your PowerPlane installation shapes up.
Thiel has worked with Madisound since the 1970s, so they know that we want unflavored, technically accurate caps and resistors. I went to them for advice for my PP rebuild and they recommended Mundorf as the "winner" in their customer experience. Mundorf has a deep range of solutions and I have not yet chosen mine along their continuum. Thiel routinely bypassed good Solen PolyPropylenes with a smaller value of Styrenes. Styrenes are very expensive due to manufacturing losses; they have been replaced by higher-performance PPs. We coveted, but never used in my time, Teflon bypasses which are extremely clean, neutral and stable over a wide current range. If I were hotrodding an upper end Thiel, I would consider a Teflon bypass in the tweeter feed.

My "lost" post included a note about hookup wire. I have seen people "upgrade" Thiel hookup wire. I don't buy it. Thiel (lexington) hookup wire is 99.9999%, long crystal, teflon jacket, 3 twists per inch. I've never heard or measured better from any boutique / branded wire. The only thing I am considering, because I must increase my lengths for my outboard crossovers, is Paul Spelz's AntiCable 3.1 for hookup wire. It is high-grade copper with only enamel insulation, similar to our six nines coil wire. Dielectric absorption is the problem. Teflon is great. Less coating is even better.
Yes, the hookup wire came from Straightwire, which is a price / purchasing convenience. The relevant particulars include the wire, the jacket and the twist, which trumps the source.
Cardas makes great cables. My hope is to supply subtle information that may not be obvious to all. Crossover networks can be very easily scrambled via changes with unintended consequences.

Speaker cables are designed for unknown load characteristics and environments. These hookup wires operate in very specific conditions, and this particular wire configuration has been optimized via meticulous design.  
On another matter, I am looking to buy a Thiel SS2 ( or SW1) subwoofer for our non-profit village arts center. We mentor developing regional performers using better-than-expected sound equipment. I placed an Audiogon want-ad. If you know of anything out there, please send them my way. Thanks, Tom