Thiel Owners

Point Source has as well as time coherent have become rather loosely defined. Note the ports.

Point source, yes, absolutely, at least in their LS50 with no other drivers.  But that's only one non-essential attribute of full-coherence.  Vandersteens' achieve it all without any concentric drivers.  All Thiels except the SCS4 (?) have the wide-bandwidth woofer (and sometimes other drivers too) some distance from their coax mid/tweet.

I just bought a pair of LS50 Metas to supplement my 2.4 due to a hypersensitive deranged neighbor (no lower bass output and lower volume capabilities), but need more time for a thorough A/B to get the true measure of them, as my 2.4s over the past decade have become my reference in my long-term acoustic space. 

I'll report here when I can arrive at firm conclusions, as xyzsantabarbara loves his previous-gen LS50s and his 3.7s, and the Metas are getting serious accolades, many that I can confirm are compelling and actual.

@sdecker 
Thanks!  Reason I asked is that Kef (like Thiel) bills the Uni-Q as a point source.

jazzman7:   The KEF Uni-Q would seem to disqualify itself from this discussion due (at least) to their use of a second-order crossover.  Indeed, the step response plots from Stereophile look nothing like a time/phase coherent loudspeaker:
https://www.stereophile.com/content/kef-ls50-meta-loudspeaker-measurements

tomthiel

Thank You, as always, for another Thiel Audio history lesson.

Happy Listening!

A word of caution, Ohm no longer uses genuine Walsh drivers, and hasn’t  for some time now.

@tomthiel, As I understand it, though the Walsh driver is conical, the bending wave travels faster than the speed of sound, thus being able to produce step and square wave response indicating time preservation. The omnidirectional dispersion, while perhaps tricky for small room placement, is capable of charging the room rather uniformly. The original Walsh drivers were a difficult balance in that they required quite a bit of power yet could be damaged if overdriven. Modern versions claim to alleviate these issues, though extreme SLP’s still seem to be the forte’ of other designs, distribution seems somewhat limited, and they are not inexpensive. I have not heard any of these type of drivers in decades. I would welcome the opportunity!

Unsound maybe you found this.
With much info contained.
I would be interested in seeing how the driver is terminated on the edges so some polarity of the signal does not return into the path of the next uncoming signal.
Same thoughts on any of the Walsh drivers the inside and outside of the cone must react with some signal inversion. Tom.   https://www.bendingwaveusa.com/technology/

There's some explanations of the Walsh driver characteristics at Ohm's website - https://ohmspeaker.com/technology/

So a question, where would Kef's Uni-Q concentric driver array fit into this mix?

The ESL-63 uses (if I recall correctly) a cascading time delay crossover over concentric rings of the diaphragm to create a whole diaphragm motion with all points equidistant from the listener's ear. What brilliance!
"Walsh" - type drivers use bending in their method of creating the cylindrical column of moving air pressure waves. So bending is part of their basic system mechanics.

Discrete drivers attempt a uniform air propagation wave-front  via multiple driving sources, which must remain flat to engage the air mass properly.
Unsound - do you know if the Walsh-type driver actually produces intact step response at the listener's position?

I think the old Walsh and new DDD mostly bending wave drivers (there seems to some combined pistonic motion too) might prove that pistonic motion is not a requirement for time and phase accuracy. The Quad ESL ‘63 is another work around that would appear to dispel the notion of a pistonic motion requirement for time and phase accuracy, Of the above mentioned examples, It should be noted that none use 1st order cross-overs either. Though to be fair I think only the limited production Walsh A could be considered full range, and that model seemed to be plagued with reliability concerns. HHR Exotics claims their updated version of the Walsh drivers have addressed many of the concerns of the original Walsh drivers.

CT - a few general thoughts here. I am aware that Richard uses the term ’pistonic drivers’ and what he means my it, and agree that it is highly desirable; but there are many designers who don’t want it. There has been considerable convergence of thought around accuracy of reproduction since the 1970s when Richard and Jim were making breakthroughs. I say breakthroughs because at that time it was not widely accepted that ’truth in reproduction’ was a desirable thing. In fact, most designs were developed to deliver their particular euphonic flavor. Within that context, the Thiel / Vandersteen "everything matters, and accuracy is the goal" perspective was unique then, but quite widely accepted now. Note that Dunlavy and a few smaller designers also honored full coherence. The marketplaces of ideas and commerce have not generally supported the extra difficulties of coherence.

In the context of ’getting everything right’, drivers must move pistonically. And as time goes on, more and more do so. I don’t know whether RV has any actual corner on that claim, beyond coiling the term and using it in his promotion. But he does share his design values with John Dunlavy and Jim Thiel, requiring flexural rigidity. I’ll take a little memory trip here. Thiel’s coherence awakening came after the 01 and 02 (1976) which had normal third and second-order crossovers (all polarity-correct.) The 03 development began in that normal way, but veered to first order in an organic procession (which I’ve mentioned here before.) That development of a phase coherent system required the development of more pistonic drivers. Note that many (normal) designs use the flexural cone delay of the circumference lagging the apex as a way to mitigate the reverse-polarity negative going onset transient of the upper driver from the typical second-order, inverted polarity crossover. In other words, a floppy driver causes less of a particular problem than would a stiff driver in that common second-order/ inverted polarity design. But that advantage evaporates with a coherent first order crossover, while keeping the significant time, phase and harmonic distortions of that floppy driver.

So, back to 1978, the final 03 is coherent, but the drivers are ordinary. Next product in development is the 04, a 6.5" coherent two-way. Jim developed a double-cone woofer for that product, which was patentable (and eventually was Thiel patented.) The front cone is a curved flair and the back cone is straight, both driven by the same voice coil and to the same surround attachment. The double cone triangulates the weak circumference, creates double propagation paths (introducing self-damping), uses the air captured between the cones as an averaging medium - all producing a very stiff pistonic system of light weight and low cost. Alas, before the finalized 04 was introduced, one of the cones was discontinued, and no workable mates could be found until we grew enough to commission our own cones.

Please pardon my spotty memory, but as I recall, the first product to incorporate that double cone geometry was the woofer of the CS2.2 introduced in 1990. It took that preceding decade to develop the sources, solutions, patent and manufacturing infrastructure to make the concept a reality. That geometry is used in the CS3.6 midrange and probably other Thiel drivers. I left Thiel in the mid 1990s and don’t have first-hand information of the further trajectory of that double-cone solution.

RV’s solution using carbon fiber over a balsa core is very effective, along with very expensive.

As far as Jim developing his pistonic drivers, I propose that he made steady progress toward that goal throughout his career. In the early 90s, we conducted in-house cone development that significantly improved specific rigidity via material and profile and taper geometry. I further propose that Jim's statement pistonic driver, was the CS3.7 / 2.7 midrange with its radial corrugation diaphragm, which represents a conceptual and technical breakthrough. The 3" diameter voice coil bisects the radiating area such that there is equal mass distribution on either side of the motive force. In other words, the driving force is balanced rather than propagating from a voice coil at the apex to a passive rim at the surround. In cross-section, the (half) diagram is a T with the wavy diaphragm on the top and the vertical stem being the voice-coil former - driving the diaphragm from its centerline. The corrugations keep the diaphragm from bending for a near perfect piston. I would love to see comparative Klippel pix of the Thiel driver vs the Vandersteen driver. I bet they are both world-class and that the Thiel driver costs a fraction of the Steen. I hope that Jim’s driver might live on. I consider it his crowning achievement.

@jafant, ....”....measure richer....”....?

ctsooner

2nd Note- did you upgrade from stock fuse(s) in your AX-5 Twenty Amp?

Happy Listening!

ctsooner

Good to see here again. Thank You for sharing your thoughts.
Reading through this thread, I talked about how close the Vandy 3A Signature trailed a Thiel CS 2.4 loudspeaker. The CS 2.4 wins because of its inherent rich timbre. Moreover, I found the CS 2.4SE a measure richer which is unbelievable in presentation. 

What gear is in your system now?

Happy Listening!

Happy Weekend Jfant!  I have to share something that I've wanted to share for a while now.  Every time I listen to my Vandersteen Quatro's, I'm reminded of the CS 2's from the early 80's.  I find it so interesting that Richard Vandersteen and Jim Thiel both produced a bass EQ (first of Jim's designs) as well as phase and time correct speakers.  They each had a different sounding high end, but both are the most coherent speakers going (the original Thiel's).  If Jim was still alive as Richard is, he too would have come up with his version of the 'pistonic' moving drivers just like RV.  

To me, these are the two greatest speaker designers as it's impossibly to say that a time and phase coherent speaker isn't the most correct way to reproduce the sounds that we call music.  That's basic physics.  Even AJ Conte (of Basis Audio, RIP) loved these two brands for how they achieve their great sound.

Just wanted to share some random thoughts.  thanks folks.

Happy Friday! All

Heads up:  There's a

Conrad Johnson Premier 350SA

For sale on Audiogon right now.  Highly valued classic that rarely comes up and I'm not sure if it's in this thread or others, people have raved about the pair of Thiels with that amp.

I have read about these updated Ohm Walsh bending wave drivers before. Noticed their internal acoustic panels use a polymer sheet that incorporates steel shot..I would rather mix the shot into the cement and have the cement seal the wooden pores.

The most interesting German Physiks speaker line (I'd love to hear a pair!) use interesting cabinets, damping and drivers(!).
 
German Physiks Carbon Mk IV Loudspeakers — German Physiks (german-physiks.com)

I will experiment with the mix on some plywood first and see how the coating hangs on. After drying I may have to spray coat with a low shear acoustic paint I have been working with as a sealer over the Micro Bearing. Tom

A friend of mine has a patent on the selection of travertine stone to be used as an acoustic  sink for the endpin of cellos. The right tile removes the wolf tones present in almost every cello..You may research travertine stones and cut as Tom suggested. Debbie’s website is Cellostone.com

With the absence of the original Cascade Vbloc. I will experiment with quick set cement and mix in a quart or more of Micro Bearing steel and trough on like thin set. Careful to measure and match the amount laid out so the stereo pair have the same volume. Let thoroughly dry for a few days and then carefully vacuum out what may have fallen. Tom

.

jon - you're on it. When developing the CS5 cabinet I explored custom ceramic tiles for the interior, attached with a researched mastic adhesive - it worked extremely well. There were two big problems. 1: it was too heavy to ship and handle. Dealer home delivery was the deal breaker. 2: the tiles were not always flat and the ratio and durometer of the adhesive layer would change the tuning of the enclosure depending on adhesive thickness variability, thereby changing the final tweak voicing of the system.

For your in-place situation, #1 may not matter. #2 is a small issue (and no, I don't remember adhesives options or winner 30+ years on.) It's worth exploring. Also, you will change the acoustic volume of the enclosure, but it won't matter a lot. I suggest finding the most active surfaces with your fingers or stethoscope and treating those. High likelihood includes the top and halfway up the sides. Please let us know what you do and how it works.

If I were going to try to reinforce an mdf box the first thing I'd look at is porcelain floor tiles.  They're incredibly stiff and tough.  They don't resonate much but what little they do is at a high frequency.  I'd think combining them with mdf would be an ideal combination.

Tom,
Thanks very much for the detail.   I'm not a handy-man type so wouldn't do that myself, but I'm saving that info and maybe some day I can get a local speaker repair shop to do it for me (if not send them to Rob).


BTW, speaking of getting the 2.7s to "disappear":


I just tried a fascinating tweak with the 2.7s.


To backtrack, I spent a month several years ago putting together an isolation platform for my turntable.  I bought tons and tons of footers and various isolation material (hard and soft), testing most of them with vibrometer apps etc.   By far the most effective were the Townshend "seismic isolation pods."   They are a spring-based design that holds up the heavy turntable and layered platform.   Without the springs if you stomp around the equipment rack with a hand on the top shelf, you can feel tons of vibration.  Also a Seismometer app measures plenty of big vibration spikes with ringing.  



But with the spring pods under the platform, stomping around you can't feel anything getting to the platform, and almost nothing registers on the vibration app!   So quite objective verification that at least some register of vibration is not getting through.


That experience made me curious about the spring-based speaker isolation platforms sold by Townshend, which get great reviews (what doesn't?).    But those are pricey so I thought I'd try an experiment with some cheap spring-based footers on amazon. 



I placed them under the Thiels and just finished listening for over an hour.Wow, they work!  The effect was very similar to when you get a subwoofer dialed in really well - not extended bass but a perception of clearing up and tightening of the entire frequency range, starting in the low bass.  Bass instruments were tighter, floating better in their own space, every thing had a bit more clarity top to bottom, and the speakers disappeared better, the soundstage taking on more of that wide CinemaScope width of the 3.7s, instruments to the side less stuck in the speaker!


I certainly wouldn't say they suddenly sounded just like the 3.7s, but it sure was fascinating for a cheap tweak!
The problem is the speakers get a bit tippy on the spring footers so I don't think I'll stick with that particular solution (because I have a lot of foot traffic in that room right past the speakers to get in and out).   I'm sure with a bit of ingenuity one could make some outriggers using the footers for greater stability.   But I have a feeling I may pick up the Townshend speaker bars in the future.

Just in case anyone is interested, Saturday Audio Exchange in Chicago is listing a pair of CS 7.2 in teak for $4499.  They are also listing an MCS-1 for $899.

Prof - I’ve only heard the 3.7 and 2.7 once, when auditioning the final prototype 2.7 at the Thiel factory in 2012. We all heard what you are hearing.

There’s probably more to it than the baffle. A few years and $six figures were spent optimizing the 2.7 within its budget parameters. The aluminum baffle is a contributing element, but any upgrade would have to be from outside, since the interior has multiple shelf braces in the way. A person might route a pocket into the MDF baffle front to seat a custom aluminum plate. Serious undertaking that I doubt Rob would take on - but ask him. You would get significant improvement using counter-top laminate (Formica, etc.) rather than aluminum.
An effective and feasible upgrade addresses the 2.7 midrange xo feed which goes through a 400uF electrolytic cap as well as a series 20 gauge feed coil, without any shunt to ground. Jim never used electrolytics in series feed stations (after the 02 in 1976). That "caught in the box" effect is something that big E caps do. I have developed some substitutes from Clarity Cap 100uF x 160 volt CSAs. I doubt you have room in the enclosure for them plus they’re fairly expensive. Note that Jim’s solution for the 3.7 is a cap bridge with multiple 75uF PPs. The feed coil in that station in the 3.7 is 18 gauge for about double the current / resistance performance.
If I were in your shoes I’d consider the following:
Baffle treatment: remove the drivers and the threaded inserts (if any).Mount 1/2" (or larger) birch dowels into holes drilled into the edge of the driver openings, at least an inch and preferably farther behind the front surface. Wood screws into that side grain of the dowels will couple the drivers more tightly to a greater cross section of the baffle. Use viscous gasket goop behind the drivers (Permatex type 2 non hardening) to damp the natural interface resonance. That mounting on a formica face gets you pretty far up the performance ladder.
Crossover: replace that 400uF E-cap with 4 @ 100uF in parallel. Consider replacing the bypass caps with ClarityCap CSAs. While you’re in there I’d swap in some Mills MRA-12 resistors in that series midrange feed. Same for the series feed in the tweeter.
That’s some low hanging fruit and something that a good bench tech could handle if it’s more than you want to tackle. Rob may have suitable parts or advice, or you may contact me for specs and sources.
The 2.7 is a very nice speaker and in some ways easier to take on a broader range of material and amplification than the 3.7. But immediacy and detail are relatively compromised.

@tomthiel

I think I've brought this up before but...
One of the differences I heard between my 3.7 and 2.7s was a finer, more subtle sense of detail on the 3.7s and the 3.7s "disappeared" a bit better.So even if an instrument or voice was panned hard right to the speaker location, the voice would float around the speaker.  Whereas the 2.7s have a teeny bit more problem getting the sound "out" of the speaker in the same situations.

Apparently the baffle of the 3.7 was metal (aluminum?) where there was a bit of cost-cutting in the 2.7 so it was a less stiff material (wood? MDF?).    I presume that could be responsible for the observation.

It makes me wonder about a tweak for the 2.7s of re-enforcing the baffle from behind within the cabinet, say with metal or something that makes it comparable to the 3.7's baffle.

Is that something Rob could pull off?  I have no idea how difficult that would be.
Thanks

Happy Friday! All

beetlemania

No. I scored a sweet offer for an AX-5 in stock form. This is a very good thing, as I will send the amp back to AYRE, and enjoy a 2021 upgrade.
Any new gear headed your direction this year? 


Happy Listening!

Happy Friday! All

Resistor upgrades have been discussed and revealed on these pages for years. The greatest upgrade for me over 20 years ago was to replace all the resistors in my speakers with Vishay resistor bridges. This portion of the upgrade was larger than the cap and inductor upgrade..only thing of equal was to seal the interior of the cabinet with Cascade Vbloc..a cement like product that is drawn into the pores of the wood seals the wood and greatly reduces energy storage of the cabinet.also strengthens the corner joints that are the weakest. A speaker cabinet itself is a passive radiator..not only do the drivers  move and play but also the cabinet.

Poor quality speaker resistors become part of the feedback loop of the amplifier and become part of the signal. Upgrade the resistors.
Tom

@thoft I think V-1s were in the range $8-9k when new, depending on the version. So you might find one for about $4k or less? I think Ayre stopped making them shortly after the MX-R was introduced ~15 years ago. But I’ll bet they will still upgrade any version to the ultimate one, V-1xe.

@jafant 
I thought you already had a Twenty version?

Alright then, swapping in Mills MRA12s  is on my list. I might  need some technical pointers, but will post results when able. Give me a minute...

@beetlemania how much would a used v-1 cost? I swims if it drive 7.2’s it’ll drive 3.6’s just fine. Right? 32 fets per channel? Sounds amazing I want one.

tomthiel

Thank You for another year of hard work researching and developing (R&D) our beloved loudspeakers. Keep up the outstanding effort.

Happy Listening!

beetlemania

Good to see you, as always. I really must hear your upgraded 2.4s sometime for a sonic comparison. In the Spring, I will send my AX-5 to AYRE for the full Twenty Series upgrade.
I believe the previous AX-5/20 was a 2017 model. It is going to be interesting to compare mine against the previous Amp auditioned.

Happy Listening!

tmsrdg

Thank You for reporting your experience with Rob Gillum at CSS. 
He knows Thiel Audio loudspeakers.

Happy Listening!

I have bragged about those yellow caps as state of the art, and they were in their day

Oh, no! Time to remove the radiator again? Lol

 I do occasionally wonder about different bypass caps on the CSA coax feeds. We went with Multicaps but, in hindsight, I’m curious to hear something like the Audyn True Copper Max or Jupiter. Likewise, wonder how the Path Audio resistors better the Mills MRAs, if at all. Then again, that was a lot of work to make one change in one channel, wait for it to burn in, and carefully compare in mono. 
Maybe I’ll just listen to music and be happy rather than compulsive?
:)

With the 3.7, I wonder if Rob Gillum’s experience is related to those massive ELs which cannot practically be upgraded due to size and cost.  But, yeah, the Mills seems like low hanging fruit that is likely to make a nice sonic upgrade and for not much money.

Ayre power amps are also a great match with Thiel

100
My AX-5 Twenty and CS2.4s are singing. Years ago I ran a pair of CS1.6 with the AX-7. Also nice other than I yearned for more bass. And my only experience with the CS7.2 was paired with, I think, the V-1. That system was just short of the very best I’ve heard.

Tmsrdg - I can add a general perspective comment. The level and extent of exploration and custom development that went into passive components at Thiel was considerable. Many folks may consider Thiel's choices as strictly budget driven, but scores of hours were spent on each product to optimize and match the components both for sound and for cost balance. The biggest exception might be the resistors. Swapping in Mills MRA12s costs very little and has produced noticeable improvement in the several builds we've done recently. I have no direct experience with the 3.7, I'm merely extrapolating from general experience. 

Anyone used Vincent audio sp-331? Says it can handle 2 ohms no problems. 1,000 watt ring core transformer 300 at 4 ohms. Buddy is using one for his legacy audio signature 3’s.

I had a discussion with Rob G. several weeks ago about replacing caps in my 3.7s. He basically said don't bother, it won't be worth the effort. He sent me a couple pictures of designs he has tried with the 3.7 and maintained the sonic improvement was minimal compared to cost. If anyone else here has modded the 3.7, it would be nice to chime in at this point!

Myself and others have applied an opposite or different method to the mounting of crossovers internal to the cabinet.. We do secure the individual components to the board using rope caulk or other soft adhesives as well as zip ties. Instead of slowing down and storing some of the vibration inside we direct couple the slowed and misdirected energy to the floor or wall of the cabinet. I use small brass Audiopoints and the brass coupling discs. The board rests on these devices and the board can be secured with brass screws to the cabinet base. We have an extended method that allows for resonance tuning from outside the cabinet. This method while more invasive the improvement can clearly be heard by using a hex tool..To provide a continuum of thoughts on this mechanical conduit we set the speakers on our Audiopoints or our Sistrum Platforms and speaker stands. We use the same materials and geometry to maintain the capture and redirect direct the  exit speed of resonance to the largest mechanical ground plane..the floor. There is also a similar method that can be applied to bass and midrange drivers which also allows for resonance tuning outside the box. Tom

Thoft - I've been messing with the 3.6s for the past few months. I consider their stock components highly optimized and am therefore investigating other upgrades in priority over component upgrades. That said, there are ongoing DIY upgrades happening behind the curtain on this forum - perhaps someone might comment.
I can recommend the fruits of our research, which lands on replacing series feed caps with ClarityCap CSAs in the highest voltage you can fit or afford. Swap resistors to Mills MRA-12s, especially in feed stations.

As background, I have bragged about those yellow caps as state of the art, and they were in their day - tin foil on styrene film, they measure and sound quite good. However CC's CSA invention replaces the normal zinc spluttered end caps with a copper-containing matrix, and updates the geometry to wider and shorter, for a significant performance upgrade. BTW, I've compared the CSAs and CMRs to many of the sexy caps out there, and I believe the CCs are as good as it gets in terms of truth and accuracy, especially at their affordable prices.

Another nearly free upgrade you can DIY is to re-mount the crossover panels on rubber standoffs to reduce vibration in the crossovers.

Jimi - I recommend restoring the CS1.2s as a very fine little speaker. I use the CS1.2 drivers in an 02 cabinet to compare components,wire and cabinet treatments. Rob at Coherent Source Service has parts. I think you'll be glad you did.

Is there a recap kit available for the 3.6? Also my thiels aren’t bright like many keep saying the 3.6’s are. Very smooth. Yes the tweeter works I tested that with my hearing aids. Anyways my amp search may be pushed back yet again due to my car having exposed metal on the rocker panel that I only noticed after I took it to a car wash. (Dried Salt spray and bare metal/primer hide each other well). So more time to look for amps. Still trying to find out what the adcom has. 60+ amperes and more than 300 watts is the recommendation right? I wish there weren’t so many possibilities. More than a few people on Facebook are recommending class d amps. Will those have the power to drive thiels current wise and headroom wise? Trying to stick to class a/b personally