Thiel Owners

Rules - my comment addresses the presumption among many that zero or linear phase response is without problems. I admit that its problems are indeed minor and in the real world may be a best choice solution. For your enjoyment here's a very brief synopsis of the elements including the psychoacoustic reference to pre-ringing being more disturbing than post. I will add that today's DSP execution of all filter types with optimization is far better than my experience a decade and more ago. Enjoy. 
https://ccrma.stanford.edu/~jos/filters/Linear_Phase_Really_Ideal.html

Rules - you may be interested to know that Jim's 2nd choice was 2nd order. The 01 had been 3rd order, the 02 was second order, but not inverted polarity like Wilson, but rather both drivers in positive polarity with the X points fudged to lower the amplitude hump. It's pretty convincing; there are others here who agree. The phase transition is not abrupt and I believe you could massage a second order slope via DSP for a pleasing result with less strain on drivers and an easier time to find off-the-shelf units that would work.

Sdl4 - this discussion fits a template deeply ingrained in the mainstream engineering community: if you can't prove it, it's not real. The article is embarrassing, but beyond that it doesn't explore much of what Jim knew because Gene wouldn't admit such empirical as valid.  I will add that years later, after Jim's death when Kathy had sold Thiel Audio, I saw first-hand that same template applied to Jim's lifetime work. "None of it matters because it can't be proven and is therefore definitionally untrue."
I'll point out that one of Gene's arguments about aerospace engineering knowing more than audio hacks is especially rich. We were first exposed to the subtleties of wire by cousin Ted via GE Aerospace avionics having identified just such subtle wire effects as causing problems in Jupiter Space Probe signal propagation resolution.

They don't recognize that their thought process and assignment of burden of proof categorically negates much of the progress made in subtle technical arts.

JAFant - would you please supply a link to the Olsher article? I didn't find it searching the Absolute Sound site.

JA - On to your question. Our first speaker wire, including the 1978 CES where we introduced the 03, was home-brew made from #0 stranded welding cable configured for lowest conventional problems.  It measured well and looked impressive. Jim was also a skeptic by nature as well as we all being over-booked for time to explore elements like wire, which was a brand new arena at the time. It was probably spring CES 1978 that Ray Kimber showed us his prototype $1K / pair foot braided 6-9s silicone sealed, jacketless cable. We made a double-blind comparison, including measurements, between our welding cable and Ray's new wire. The conventional measurements were inconclusive, but certainly our welding cable didn't exhibit big problems. The listening test was not subtle. Ray's wire blew everyone away.  Guests included the editor of Audio Magazine (professional journal). Details aside, we developed an ongoing relationship with Kimber.
We also developed a relationship with Bill Low who later founded AudioQuest, and his products were always in our evaluation mix. Noel Lee of Monster Cable was in our mix, and Monster branded and sold Jim's patented user-selectable load low-output moving coil headamp. The Monster Cable products never made the cut for us,somehow including distortion mechanisms that masked the music. An important ally became Dave Salz and Steven Hill of StraightWire (together at the time) who became the distributor for the ultra ITT wire that we used. StraightWire developed teflon jackets, polished drawing dies and other leading edge technologies. It is possible that we got best pricing from SW because those guys claim that hearing the Thiel 03a is what made them decide to pursue high-end audio as their career.

There were other wires, winners and losers in our context, but I don't clearly remember the brands. I do remember that when Bruce Brisson introduced his Music Interface Technology cables and tried to interest us, their multiple samples contained defects, either of design or execution. We didn't go there. I also remember in the mid 80s, my opinion diverged from Jim's about "best wire". I included the teenage girl contingent in my comparisons and Jim developed an attitude of himself being the arbiter of choice. (Jim had begun smoking before he was a teenager and I believe he didn't hear high frequency anomalies as problems. Just sayin'.)
I left in the mid 90s and don't know much about external wire thereafter. I do know that StraightWire's best 18 gauge 3/inch twisted pair in teflon remained the internal hookup wire. The coil wire was by then sourced by Rudy at Acoustacoil who was winding all our coils by then. Ultra-best wire became unavailable after the space projects closed. But Thiel continued to use best-of-available. I remember reading some reviews where Thiel used Goertz Flat Wire to develop the 3.7 (or perhaps an earlier speaker). I never remember reading of Cardas or Transparent wire although Jim had relationships with Karen @  Transparent via Kathy in industry politics as well as with George Cardas. I heard that Jim experimented with silver wire, plated and solid, but its sonic signature was so different as to necessitate a choice based on likely user selection. Thiel's price-class was always modest and silver wire is in a different league, he went with copper.

That's about all I remember. We routinely evaluated new wire configurations and brands and most of them were judged as overpriced and compromised. We were dumbfounded by the margins we saw in the wire sector of the industry. Dick Olsher and Jim had a mutually respectful association. We thought our stable of commentators and reviewers to be first-rate in their approach and understandings.

JA - thanks for the link. I'll cover some ground, perhaps repeating some stuff from previous posts. Wire was an essential element in Thiel's adoption of first order coherence. We sweated blood for a year and a half in 1977 - 1979 to decide to adopt first order slopes over the second order alternative. Second order was so much more forgiving, partially because the steeper driver rolloffs made their work more benign, but also because we came to learn that coherence required the ear-brain to assess the musical information as REAL and therefore deserving far higher scrutiny than reproduced music. With that backdrop, we were stuck. The coherent speaker showed far more unexplainable problems than the less coherent second order speaker. Beyond the statement that everything mattered, I'll point out two elements that mattered most:1: wire and 2: driver basket material.

First #2: all our baskets, like most everyone else, were stamped steel. No matter how much epoxy and damping we applied, there was an audible sonic problem. Jim wondered out loud whether there might be eddy currents in the basket. We found some aluminum baskets and the problem vanished, even when the aluminum basket was demonstratably more resonant than the reinforced steel. Short version.
Next #1: Wire was not in the vocabulary yet. We were using first-rate Electrolytic Tough Pitch, like everyone else, both for hookup and coils.I previously recounted a visit from our aerospace physicist cousin Ted Lyon who listened to our demonstration of the problem we couldn't solve in the coherent system and how it vanished in the non-coherent system. Ted recounted a rather elaborate program whereby GE found wire crystal margins to be causing subtle distortions which acted a lot like what we were describing and hearing. He got us a sample of ITT's 6-9s ultra wire, fixed the problem and the rest is history. Lots of interesting history, but too much to recount here.

So our modus operandi going ahead was that everything mattered and our job was to determin how to proceed rather than trying to prove anything to any logician. Manufacturers are not research institutes, we willingly collaborated with anyone who wanted to understand anything, but drew a line before getting involved with anyone who tried to prove the negative. Deep in our corporate culture was that the ear-brain was far better at detecting naturalness than any scientific instrument or theory. 

Sdl4 - very well stated. There exists an arrogance of intelligence which imagines it knows everything when it can explain anything. Thiel's founding attitude and guiding principle was that we only understood a small corner of what we were dealing with and that we better remain open-minded and humble if we were to make progress - making progress on all fronts was at the core of our work ethic.

Although I and Kathy were integrally part of the early decisions, directions and perspectives, it was Jim who took the bit in his teeth to create the electro-acoustic solutions. And he got better and better. My chief contribution was building a company and creating a manufacturing platform and capacity to support and manufacture Jim's designs. A manufacturing company defines itself by what it can actually accomplish as well as the designs it sets out to make. Our plant could make things with high precision and repeatability at low cost, which allowed fairly sophisticated designs to be translated into real world products at affordable prices. Additionally, I developed a very capable "project shop" for in-house prototyping, including hydro-spinning cones, machining motor assemblies, making production tooling and producing finished products, troubleshot and production-ready. In my travels, I've never seen anything like it, especially at such a small scale. Thiel remained under $10million / year with 50 or fewer employees. That's tiny for our high level of vertical integration.

8th-note - gotta go soon, so you get the short answer. Do some practicing with a vacuum cleaner and then pull your dent out with vacuum. If you don't hear voice coil rubbing, you're not doing damage. When it's as smooth as you can get it, put the grilles on. The speaker was meant to have them, plus you won't see the dust-cap.

Sdl-4 - FWIW, Straightwire remained an active / interactive supply partner with Thiel from early 80s when they began until 2013 when Thiel was sold. SW knows quite a bit about wire, although they sometimes seem slighted in the market for lack of eber-expensive products. I would be most interested in learning how you guys consider SW and their products. I also hope for any feedback about Morrow, which is where I landed with little to no meaningful comparisons. Any thoughts?

Sdl-4 - I think it is considered a solid value and they also sell into the pro market. Harmon among others use their products.

JA - In my wire investigations I have learned that 6-9s wire is nearly extinct and even 5-9s is practically unaffordable. As the world changes toward miniaturization, highly complex component circuitry and wireless data and signal transmission, wire is less critical. It seems that some of the best sources (both audio and aerospace) are using 4-9s with careful casting, drawing, gauging and coating technologies. To your question, Thiel maintained a steadfast commitment to using the best wire available. I know that solid 18 twist isn't very sexy, and I am now comparing alternatives with coaching from wire guys, but that 4-9s x 3 twist in teflon certainly performs well. Over the years it was routinely tested / listened to against many alternatives. Remember that, unlike external speaker cable, Jim had the advantage of developing each driver's crossover as an entire system from input to driver, to include all wire effects as part of the global circuit equation. In other words, the inductance, capacitance and resistance and their subset effects were accounted for by measuring the global system.

Jim was trying to make that point in the interview, but Gene wouldn't allow it to really go there as a stepping stone to further investigations. It's quite easy to pot-shot any designer's values and approach. But I can tell you that Jim milked very high performance out of complex circuits that could only be afforded by scrutinizing the cost / performance ratio of every single element.

Prof - it would be helpful to me to know what interconnect and speaker cable you are using in your system, as well as the other components as well as your comments about strengths and weaknesses. I am calibrating my experience and understandings from a perspective of long absence from the arena. Your perspective, especially on cable, would inform my thinking.

George - I am especially interested in learning your methods of comparison or evaluation.
(This inquiry is an honest one)

Prof - your opinion is quite useful to me. I'm casting a wider net than my personal, usually quite old, experience. I presently have bought a long run of unterminated ProCo cable 12 x 4 which resembles your links. Bluejeans' welder sounds wonderful. Terminations are serious business. I have not tried AC cables; although my queue has some shielded hospital cables to compare with "normals". I can imagine EMF interference issues. I have an EMF meter and was amazed by the levels of EMF around my gear. I installed 2 new outlets and simplified routing which significantly reduced those levels. I think I heard a more relaxed musical presentation, but I had no assistant and no way to A/B, so the result is merely a move in what seems to be a good direction.

Thank you. Tom

George - I'm out the door till Friday, so just a quick response. Thank you. I suspect a lot of audiophiles envy you . . . listening to music for god's sake! I see our job as equipment providers as serving just that desire, to hear the whole envelope. The devil is in the details and turns out to be a big challenge.

I'll eventually muddle through. Thanks again.
Tom

thosb - vertical lobing is a central draw-back from first order crossovers. Your ear must be at the right height to receive proper integration. The closer to the speaker, the more critical is the correct spot. Target design was 35" at greater than 8'. (I heard that 35" migrated to 36".) My studio doesn't have a couch or living room seating and the lowest setting for my adjustable chairs gives 42". My solution uses a drywall square - a big aluminum T. I clamp it to an inside speaker face with the long arm centerline at 36" off the floor and tilt the speaker until I am sighting straight down the square's long arm. Vertical tilt is much more important than toe-in due to the vertical arrangement of multiple sound sources. Coaxes are more forgiving than individual drivers, but still interact with the woofer.

FYI: part of the mechanical upgrade is a threaded front spike for easy tilt adjustment. 

Beetle - I took your advice and ordered Cardas internal wire, same as yours. Not yet had the opportunity to compare. Thanks for the nudge.

All - a little progress report from the hotrod garage. This past week I got first batch items of both the new terminals and the heatsinks. I think I mentioned the high purity copper bolts for terminals. But, heatsinks you ask? I know that heat is broadly everlooked as a problem in hi fi, since we’re not filling stadiums at 120dB. But, heat is a problem nonetheless, and it keeps showing up as audible.
I knew we replaced lots of burned voice coils at Thiel. I knew there were charred masonite crossover boards. I knew that styrene caps melted when too close to crossover resistors. And I knew that Jim actually goosed the Smart Sub output to compensate for VC heat to compensate for reduced output, with a thermistor feedback circuit to the amp. Good and fine remedies as far as they go. But it got really real when I was experimenting with crossover components hung by twine to mess with proximity and directionality for my new layouts.

Allow me an aside here. Over the years we explored feeding coils from ID or OD and gradually landed on OD feed and ID tap. That’s opposite from received wisdom; but my present experiments confirm. I like confirming experiments and conversely hate coming up with any different result than Jim did. So, I’m happy. But here’s an interesting thing: it seems that the coil orientation in geo-space seems to matter. I placed the coil under test quite distant from any interacting fields, and the sound changes as the coil is rotated and turned in space. I don’t know if I’ll gather actionable knowledge, but stuff does get weird. Everything is audible.

Back to business. All that handling with pink noise and music at 100dB, and guess what? The coil got hot enough to start unravelling when hung by a lead wire, and hot enough to burn my fingers when I caught it. That’s hot. Further experiments confirm serious heat in various places in the XO. This is fairly old news that I’ve reported before. But where it lead me is quite sweet. Both the speaker and the XO network will have heat sinks. The speaker’s 'hot snowflake' sink will be on the outside of the cabinet behind the drivers - which comes later. Now, I am building out various levels of XO and by a twist of fate, all will have spot heat sinks, rather than a hot snowflake on the top models only. The trick is scrap. The layout of the hexagonal trapezoids for the hot snowflake on the cabinet yields some offal which lends itself to individual small sinks near heat generators in the XO, which being outboard, can dissipate heat to room air. I had already decided to replace the final output solder lugs of each driver section with bolt-down terminations in conductive grease. Performance seems as good as solder, plus each board can come out without de-soldering. Each of those three bolt terminals (hot lead for each driver) now has a round pin heat sink on the opposite side of the board. Soon I’ll know if I can now touch those coils and resistors without getting burned. At any rate, we’ll dump considerable heat at the XO spot sources before sending the signal down the wire to the speakers.

The heat sinks and the pure copper bolts for terminals showed up this week.

Thosb - Since you haven't gotten a response to your Dunlavy / Thiel query, I'll throw in some observations. I have not directly compared the two brands, but I do have some experience with Dunlavy which might be relevant. In my consulting work after Thiel Audio, Dunlavy was among my contacts, where I saw first-hand how they approached the work. I would call John's approach nearly identical to Jim's, with Dunlavy having more investment in equipment, patents and broader background in the art.

The company started as Duntech in Australia where John D. worked in the high-energy antenna realm, holding multiple patents - that company had considerable government support as they piggy-backed the loudspeakers into the antenna infrastructure and contracts. They moved to Colorado Springs as a private enterprise for more direct access to the North American market, with the financial backing of John's patent attorney as partner. Their facility was enviable - including two anechoic chanbers and considerable interactive production measurement / analysis tools. Every speaker was developed and tested with multiple / near, mid and far-field mic arrays. Their crossover layouts concentrated on stray electromagnetic interactions. They were net first order, like Jim's with similar attention applied to similar methods and outcomes.

Another departure was their cabinets, which is why I was there. They allowed vibrating panels (like British monitors), incorporating those resonances into the sound sculpture, and ignoring the resulting time-domain slurring. Similarly, the square edges introduced diffraction, which seemed of little concern to them. However, I see that more recent models paid considerably more attention to those aspects which I had assessed as weaknesses.

I note in the reviews, that John Dunlavy (a rather commanding presence) pushed back very effectively against the misleading close-miked measurements by Stereophile. Thiel took a "gentleman's attitude" and rarely if ever commented publicly on the misrepresentations of such measurements.

Dunlavy aimed for higher retail prices against lower manufacturing costs than Thiel for a solid profitability, and thoroughly well executed designs. Dunlavy seemed a one-man-show on my visits, much like Thiel. The ability to carry on without the founder's focusing vision and unique talents is very difficult. There are only a few products beyond Thiel which interest me and which I recommend when asked. Dunlavy is one of them.

Prof - I saw his live vs recorded setup, although never witnessed a test. His large anechoic chamber had one wall that opened onto a larger space. The combined space had a pair of speakers set-up and could accommodate a chamber or jazz ensemble positioned between the non-operative speakers. He was equipped to record (at that time it was direct to DAT) which he would then play back without any one or anything moving. The set up was beyond reproach and something like what I envisioned for Thiel in my dreams, but we were never flush enough to implement. Not shy at all, but his products delivered. I only heard them there at his factory around 1995, which was first-generation early goods. I'd like to hear a pair of SC-Vs or VIs.

Prof - I only saw the setup in the factory and did not witness a demonstration. But John's explanation did not include a blind component, rather it was a live vs recorded comparison tool. The "band" would play and be recorded live to listeners, and then that recording was played back immediately to the same listeners in the same place - very few uncontrolled variables.

I have read about show demos with a guitarist, etc. between two speakers who may or may not have been playing the strings as the recording of the previous verse may or may not have been coming through the speakers. That's second-hand hearsay, but the boldness itself is impressive.

Jafant and Prof - I don't know if it is well known that Thiel and CJ had a very close relationship to the extent of many visits as well as trade of equipment, ideas and methodologies. We used each others' equipment both publicly and privately as well as cross-polinated ideas and solutions. Although Thiel generally used SS equipment at shows for its neutrality, dependability and bass control, we used tubes quite a bit for development. Our critical listening / explorations most often were carried out with CJ and ARC amplification with the SS amps for verification.

In my first 20 years time-frame the CJ x Thiel relationship was by far the closest peer interaction that we had. Kathy and Dawn stay at Bill's house in DC in their travels there.

Prof - my personal AHA moment was somewhere around 1981, possibly with the introduction of the original CS3 at Chicago CES. We used Tim DeParavicini's Esoteric Audio Research pre and power amp. I was dumbfounded. Jim dismissed the pluses because he couldn't get past the minus of insufficient deep bass control. BUT, I never really heard such magic again, probably because I got so deeply immersed in factory-building that I lost track of the musical experience.

We usually had a latest CJ and ARC model in our listening room. All those amps seemed to vanish before the bankruptcy auction except the Krell FPB-600 in Jim's lab.

Arvincastro - my comments might be from left field, since I don't have much direct comparison to hi fi gear. For my work upgrading classic Thiels, I wanted 3 dissimilar amps for cross-checking upgrades. My main amps are Classe DR-6 pre and a pair of DR-9 power amps, which I have used for 30 years, know very well, and mate well with Thiels. In 1990 they were pretty decent entry-level high end with strong reviews. In addition I recently bought an Adcom GFA-555mkII, which to me represents a mid-fi amp with some hi-fi cred. My reference amp settled as a pair of Benchmark AHB-2s. That amp is primarily a pro amp, turns up in a lot of mixing and mastering studios, plus got Class A ratings from Stereophile, Absolute Sound, etc. Its claim to fame is absolute neutrality and vanishing distortion in a small, affordable, Class H package. I don't know what hi-fi aficionados think of it; I have asked here to no response, and I haven't seen it in the chatter. I am pleased with it as a colorless, honest straight wire with gain. FWIW.  

Todd - I can't answer that question due to the radical divergence of individual needs. Big room and/or loud level can magnify power requirements by large multiples.
That said, unlike other circuit topologies, the power stays absolutely clean until it quits - limited by fast protection circuitry.My situation is unusual in that my studio has 2 real, exterior walls, but the interior walls are porous, allowing few reflections or standing waves. The ceiling and floor are normally framed and therefore somewhat lossy. The studio occupies a corner of a 30'x50'x8' space which is open to similar spaces above and below it. So my listening environment is effectively quite large. My peak listening volumes never exceed 100dB, usually around 85.

In normal 100w/c stereo mode, the clip lights have rarely flickered, but have never tripped. In 400w/c bridged mode I have not reached any limit. So, the AHB-2 acts like a larger amp than it measures, probably due mostly to staying clean all the way to max, rather than gradually increasing distortion as most amps do.

Benchmark offers a generous home trial audition. I suggest you A/B it in your system with full send-back guarantee.

Clear and Beetle - thanks for the good question and the excellent answer and sorry to compress both into such a short two-word summary "radical divergence".

ronkent and sdl4 - thanks for your feedback. I'm getting one and will let you know what it does in my system.

Guys - I would like to hear your opinions regarding the PS Stellar Gain Cell Pre and DAC for possible purchase as an affordable alternative to my sole Classé DR-6 preamp.

Among my requirements of detail and so forth is that neutrality is very important to my work. Please advise and comment.
Thanks, Tom

SDL4 - Thanks for the tip. I have not gotten my mind around power cords except in one way. My Electromagnetic Field Meter registers large and variable EMF fields around all the equipment. It seems possible that shielding those fields via a shielded cord might clean up the supply signal. But I don't even know whether Audio Power Cords use a shield. So, I am ignorant of the power cord debate and don't have the mental resources to wade in; I'll stay with Prof on the sidelines. But, someday I'll give something a try, and that is likely to be your Forte F3. Thanks again.

Awhile back, Rob told me that 7.2s "never" come up for sale and "almost always" are still owned by the original purchaser; as well as "most" CS7s were upgraded to 7.2 status with new Thiel drivers and XO modifications. Seems like they're keepers. I hope to hear a pair some day.

jafant - I would suppose he has everything, but please check with Rob and let us know. I believe the 7.2 shares its high coax with the 2.3 and the other drivers were Thiel design and in-house manufacture.

Batmanfan - I claim ignorance of what preamp Jim used for the CS3.7 development. He used the Krell FPB-600 and Goertz flatwire.

How he approached equipment, in general, was to work with the obvious allies in the business, those brands which would be demonstrated and sold with our speakers. They included Audio Research, Bryston, Krell and Levinson - I remember the Pass Aleph 0 that Nelson developed to drive our speakers well; there may have been others later or fallen through my memory lapses. There was never time to play with toys. Thiel generally borrowed and lent so that latest versions of those amp brands and our speakers were in each others' stables.

Batmanfan - I have been told that one of Jim's primary preamps was the Sonic Frontiers 2-piece gold unit. But I don't know if it was used for the 3.7s. I know that at shows we never mixed and matched pre and power amps, seeming poor form from an industry allies perspective.

Ovinewar - do you have original CS5 or improved CS5i speakers?

Prof - Paul Hales is very talented and precisely educated. He got his degree in mechanical and electrical engineering for the purpose of designing loudspeakers.

Rossw - To me, the 3 / 3.5 seems the quintessential Jim Thiel design, before he had to cave to ported bass for practical reasons. We were breaking new ground in those early days, and I am pleased the early products stand up today. The 3.5 is near the top of my list.

Ovinwar - the CS5 was Thiel's first application of in-house Finite Element Analysis, applied to all aspects of development. The original CS5 tweeter (also used in CS5.1, 3.6 and 2.2) was wholly developed in-house and represents a giant leap ahead, beyond what we could buy in the marketplace. The other drivers, MB dome upper mid, Focal lower mid and both Seas upper and lower woofers were the closest to our goals that we could get from those various suppliers. After introduction, we developed custom motor manufacturing which we applied to those non-tweeter drivers for considerably lower distortion and greater clarity.

Most CS5 owners upgraded to the CS5i, which might be available from Rob Gillum at Coherent Source Service. However that settles might influence the level of performance you seek in your ancillary gear. The CS5 was our state of the art, but the bar was raised significantly by the CS5i, which could justify ultra-performance signal purity.

Kenazfilan - the Bose 901 was a huge marketplace success at the time we were developing our initial ideas and prototypes. Audiophiles and specialty stores nearly universally rejected them as gimmicks, but there were some valid ideas in there. The crossoverless multiple driver does preserve phase relationships, which are only partially obscured by the small differences in distance to the reflecting walls. The short distance between the speaker and wall minimizes the distance difference between the reflected wavefront and front-firing direct radiator. The equalizer does not introduce phase shift and the sealed bass rolls off at 12dB / octave, which is quite benign. I concur with your speculation that the design might sound like hash with higher order crossovers introducing baked in phase shifts. 
I would love to see impulse response and other "normal" tests on the 901.It might fare fairly well at low levels in a highly damped room. But, those CTS drivers were driven far beyond their linear excursion and the dust-cap "tweeter" was very ragged, and the room perimeter drive is inherently problematic and so forth and so on. I am amazed at their success. Bose spent more on advertising than on product. And it worked for them.

 The 901 was, I believe, the only speaker that Jim dissected to see how other designs coped with the intrinsic constraints and trade-offs of the art. It definitely served as encouragement that we could do better.

Jazzman - I know a little which I'll be glad to remember. You might read Stereophile's 1995 review when it was introduced, https://www.stereophile.com/floorloudspeakers/223/index.htmlI find it nearly incredible that this little, inexpensive speaker performed so very well - compare that review with products costing high multiples of its $1k+ / pair. The .5 was my last production engineering product before leaving Thiel for New Hampshire. It got the same 1" MDF walls and interior cabinet bracing, which resulted in the deadest of any Thiel product ever. The Vifa drivers were entirely Thiel-designed with the fancy magnet structures, and the "paper" woofer cone actually had multiple-fiber reinforcement and damped coating, which made it behave extremely well. The crossover, although quite simple, has the same high-purity copper coils, polypropylene caps and low-induction resistors as the rest of the family. The .5 got a full technical paper, and its attributes, performance and measurements could easily be read as applying to a $10K speaker with the exception of its bass extension. The CS.5 was an exercise is how inexpensively we could produce an full-bore Thiel speaker.
On a personal note, in 1997 I introduced a pair to the resident musical theatre producer of my new-home rural New Hampshire village, which led to more pairs, and the founding of a small local Performing Arts Foundation. I am on the board and produce musical events at our Arts Center, using Thiel speakers, which were originally borrowed .5s, then my 2.2s and now 1.6s since my 2.2s are in the redevelopment studio.

Your son is very fortunate to ge those .5s. There are plenty of spare drivers and parts to last his lifetime. I have .5 drivers here for comparative analysis and they are really exceptional. Do note that electrolytic caps can deteriorate in storage and might best be replaced before putting them back into service if more than 30 years has elapsed. I'm glad you asked.

George,
It's been my pleasure. For the record, I concur that the 2.7 is the mature work of masters of the craft, what tool-heads call ' a clean machine '. Any performance gains will come with significant expenditure. I'm happy to have you enjoying them. Best regards.

Beetle - I agree, one would not expect a paper cone to act that way. But it isn't truly a paper cone, but a multi-fiber cone with cellulose as one of the fibers. Jim developed that driver for the CS1.5 in parallel with another more expensive solution, which was chosen. I understand that the CS.5 was created to make use of that woofer.
And that decay plot also speaks to the solidity of the cabinet. Small is beautiful.

Dspr- regarding the CS5 vs CS5i. The late 80s was when Jim was exploring electro-magnetic field effects for higher resolution driver motors. Thiel developed new magnet and pole piece geometries which were applied to the CS5 midranges, woofers and sub-woofers. Also, the mass loading of the subs was changed from rubber mats to a central plug. The global result of the new motor geometries was greater definition and articulation through the lower and mid ranges. Unchanged were the upper midrange and tweeter, and no crossover changes were required.

Rob has driver rebuild parts, which are universal for 5 and 5i.ScanSpeak no longer makes those Thiel drivers.
I remember a marked improvement in articulation / resolution in the CS5i, but the impedance requirements and resulting amplification requirements remained unchanged.

Kenazfilan - regarding back to back CS5s. Jim made that comment at the press conference introducing the CS5 in response to a question as to why he didn't provide a second set of inputs. It was not a thought-out position, but rather offhand: "if you want to spend an additional $10K for a second run of expensive cable, you'd get better results with a second set of speakers". The response begs the question of the cost of amplifying the second set of speakers, their cable, etc.
Anyhow, back in the listening room after the show, we tested the idea, and it has merit. The 2 speakers per channel act as bi-polar radiators which comes close to omni-directional radiation into the room. The polar response becomes extremely uniform and the sound-field becomes immersive. One caveat is that the room must be well damped, especially at the launch-speaker end so that the additional reflected sound-power does not overwhelm the direct radiation from the front speakers. We had perhaps 8' to the front wall and perhaps 6-7' to each side wall. The front and back speakers need not be the same model. For demonstration-testing I used a Yamaha P2200 professional power amp with adjustable gain for the back speakers so that the direct vs reflected sound could be blended on the fly. Each speaker is producing half the sound while coupling better to the room for a very big, impressive presentation.

It would be hard to imagine incorporating this idea into a normal residential-sized room, and also the extra amps and cables would have to be found. But . . . I still have that Yamaha amp and a bunch of speakers in the hot-rod garage. I'll try to find time to try it out. 

rules - I for one would be very interested in your journal.

jimi handtrix - likelihood is very high that your tweeter is "blown". You can test it by taking it out and applying 6 volts DC via a battery. When you touch Tweeter Plus (red) to Battery Plus you should hear a small click and feel the dome against your finger move outward. If nothing happens, the tweeter has failed and we here can help you get a new one.
The woofer should move a lot at high frequencies because it rolls off at only 6dB / octave above around 3K± (guessing).

Rules & Unsound - I, for one, would be very interested in looking in on your discussion. Rules, I commend your work highly. Nicely done, both the work and the report.

Jacksky -  nearly all CS5s have been converted to CS5i with upgraded lower midrange, woofers and subwoofer. Rob @ Coherent Source Service has conversion kits for your drivers. I suspect that your exaggerated / loose bass may be caused by the near 1 ohm infrasonic load and sub 2 ohm load through 50 hz. If you have two 7bs, you could split the woofers and run them with one channel and the upper 3 drivers on the other channel.

Jimi - work with Rob. A voice coil is connected to the dome and surround as a moving system. Moving systems are specific to their end-use with varying mass, compliance, impedance, wire gauge and geometry. Your CS1.2 tweeter was made by Vifa, and I don't know about its repair particulars, but Rob will.

Jimi - excuse me, the 1.2 tweeter might be Seas. But either way, it is not a generic tweeter. Long ago and far away, details blur.

Not at all safe. Thiel tweeters are not ordinary in that Thiel demands response down below 200Hz. Please find out from Rob and let us know here for our records.