Beetle - I concur with your results and consider the passive parts to be important and know the work Thiel put into finding best bang for buck, always knowing that more bang could be bought. The shunts are in my experience more important than generally thought. In an AC resonance circuit all parts are in play. I am approaching the physical stuff first for practical reasons; I can compare multiple speakers with various treatments to gain experience with less investment.
Dsper - the hiss is coming from the amp chain, not the speaker.The CS5 has rubber pads on the upper and floor woofer and the 5i has center weights.
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sdecker - I don't have those models to inform any opinions. But I am messing with the CS1.5 and 1.6, which exhibit similar baffle differences. The 1.5's grille board mates with the baffle to form a flush surface with 1" radiused round-overs. The 1.6 has much larger round-overs outside of a shallow (1/8" - 3mm) pocket which holds the metal grille panel with cloth over it. I believe the 2.4 and 2.7 are like the 1.6. Within all those variables, I have isolated a sonic and measured glitch caused by that grille 1.6 pocket, either the edge of the metal panel or the edges of the pocket with the grille off. Filling that pocket with 1/8" F11 wool felt eliminates the glitch and the speaker sounds larger, the image lifts and comes out of the box. With the felt in place, the treble balance sounds right without the attenuation of the fabric. The grille magnets work through the felt for protection when needed.
This discussion segues into the grille cloth thing. A manufacturer must decide how to present its products to market, and Thiel chose wood cabinets with fabric grilles, for better and worse. Reticulated foam (model 01, and a Wilson special order) is more transparent, but not very cool-looking imho. Our fabrics got more and more sheer as they became available, but it is still there as Andy mentioned. I believe most audiophiles would prefer no fabric. In fact Thiel offered grille frames with no fabric and extra finishing to match the baffle. Nice, direct sound, but with more high-end sizzle. We could have, but chose not to modify the XO to knock down the treble. A hot-rod shop such as Thiel Renaissance could offer such mods to make the purist happier. I am presently experimenting with solutions that optimize sound quality and aren't physically objectionable.
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dsper - noise floor reduction is an element of greater dynamic range, but the ear-brain is very good at inferring musical signal that "should be" buried in the noise floor. Yes, quieter is better, but it isn't everything. I suggest classic troubleshooting - find some other components to swap and determine where your noise is coming from. Could be tube noise.Speaker noises can include a throaty hissing, usually under load, if capacitors are failing, but I would rule out the amps first.
No need to unscrew anything. Take off the grille and inspect the bottom and third (sub) woofers for rubber mats (CS5) or center weights (CS5i).
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sdecker - thanks for the photos. On my 1.6s I put a strip of aluminum at the bottom of the pocket to support the weight of the grille. Of the various felts I have tried, the best is F11 pressed wool from Sutherland. F15N (needle punched) is nearly as good and costs half as much. I have tried 1/8" and 3/8" and don't hear or measure much of any difference. Probably land around 3/16" depending on physical parameters.
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Andy - my experiments show that a felt edge at the driver surround is not good. It causes its own reflection / diffraction effect. Good results have come from beveling the felt edge and by covering everything up to the surround with Ultrasuede for an uninterrupted surface. Other designers have cut star or odd shapes for the drivers to peek through. But I don't like that either. I may have spoken too soon. I am in the middle of this stew and perhaps you might sit tight and learn from my progress as things get clearer.
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Oops, that reply should have been to sdecker.
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Beetle - FWIW, my experiments have led to a 2-layer system as having sonic synergy. Not ready for prime-time, but anyone is welcome to play.1/8" F11 (or F15N) felt plus top layer of Ultrasuede LT (lightest grade 0.6mm thick). And the clencher is covering the driver plates or bezel rings with Ultrasuede LX (stretchy), right up to the surrounds. Together these surfaces make some magic, both heard, as inner harmonic detail, and measured as lower group delay, harmonic distortion and waterfall decay. Problem is that samples of these materials are hard to get and alternatives (fake Ultrasuede or other felts) do little good. Still working.
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sdecker - let's not conclude that the baffle pocket is a sonic problem. In fact, the 20 gauge steel grille plate with its fabric fills that pocket to be flush with the edge curves. The inner edges are not parallel or concentric with the driver, and therefore probably produce little, if any reflections / diffraction.
My work is not to fix anything that was broken in the original design, but to look for ways to add more subtle solutions. One such solution is in the SoftLaunch of the baffle supported wave. I have not dealt with how to incorporate the grille into that scheme, but rather how to optimize the driver / baffle / surface interface. On the earlier speakers the curves are continuous with the front flat baffle and the grille frame is outboard. That's my present sandbox. On the 1.6, I had imagined a solution like the 2.3, which I have not yet seen, but such a solution would also work for the 5, 6 and 7. It's all a puzzle.
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Rules - by "just as good", I believe Warren refers to sound quality. See this audiogon thread regarding some pros and cons. https://forum.audiogon.com/discussions/thiel-3-5-equalizer-adviceEven if the Thiel EQ or Golden Flutes alternative were completely sonically transparent, we are left with the problem of extreme woofer and lower midrange excursion which introduces various distortions including Doppler Shift and large excursion non-linearities. No matter where you land on this controversy, it certainly represents a major historical shift away from low-order, sealed bass tuning to higher-order, ported tuning with the passive radiator. Originally Thiel speakers were going to use ports and passives in the 1 and 2 series, and equalizers and/or active woofer or subwoofers in the 3 and higher series. Jim struggled with the issue, felt some resentment with what sometimes seemed un or thinly founded critique and lack of appreciation for what the EQ brought to the table. I personally felt that the passive radiators in the upper models, even though superbly executed, gave up a unique signature bass performance. A matter of history interjects itself: in the 70 and 80 there was less knowledge and willingness to solve room resonance issues. The speakers were often blamed for room problems, since they went so powerfully deep. Warren - As you know, I consider the 03, 03a, CS3 and CS3.5 to be cognitively the same design. As such, as replacement drivers and solutions are developed for the 3.5, they will be applicable to the other models in the early 3 series. By the way, I believe those early 3 cabinets were the quietest that Thiel ever produced and, with some added bracing and SoftLaunch baffle tweaking, can be brought nicely into the 21st century. The grille frames suck more than I realized at the time. They're getting attention. Also, the modern grille fabric seems better than nothing and does not alter the frequency response appreciably if at all. |
JA - if and as a small company might be created to keep Classic Thiel speakers updated, all models are in the mix. What emerges as upgrade solutions will apply to all models because the design goals and methodologies of all models share their DNA so closely. My beginning point is early models for many reasons, but eventually I hope we can also shed light on newer models.
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Dsper - not to worry, eventually we'll make them sing. |
Brett - what you say has merit. Deciphering phase / polarity behavior has a lot to do with the ear-brain's reference, and having the deep bass delayed does affect the overall sonic fingerprint. But keep in mind that the vast majority of speakers introduce such phase distortion at every crossover point. That global, full-range scrambling may obscure the phase picture enough for the ear-brain to stop caring, drawing attention to Thiel's polarity sensitivity. I concur with your observation.
JA - I think that Jim's passives were spot-on, textbook best implementation. And the frequencies are low enough to be out of the critical midrange area. It is solid bass. The only real compromise is the inherent phase lag of the ported / passive deep bass driver.
Brett: "They would be insanely amazing if they had actual cones driven for the low bass." That debate was real in our company. Jim began the subwoofer development project with hopes of incorporating active bass into the model 3 (4) and 5. Class D was in its infancy, and that project took further years to bring to fruition, so the model 3.6 was developed with a passive/ported bass and further models followed suit. I personally lobbied for keeping sealed bass in the model 3 with an implementation of bi-amp possibility for the woofer with a higher output woofer for the model 3 and develop a model 4 with the additional low-woofer for a sealed 4-way to fill in to the sealed 5-way model CS5. The lower-priced models 1 and 2 could use the ported bass.
Those decisions were made by Jim as CEO and Kathy as Marketing Director. As we all know most speakers on up into $6-figures employ ported bass as a cost-effective solution for deeper bass with higher output capability. But I, and it seems you, and possibly many others think that the otherwise seamless coherence of Thiels above the low bass spotlights that timing inconsistency of the ported bass alignment.
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Rob - I saw and heard the first pair of 2.7s at the factory in 2012. I believe there was an angled dividing board between the lower (woofer) and upper (midrange) chambers.
I should add a thought to the insulation riddle. Many people assume that wool is best, the other synthetics are next and fiberglas is worst, due mostly to cost, where fiberglas is the least expensive. I've previously mentioned that Thiel's fiberglas is a best of form type. I don't think that I've mentioned my reasons for confidence that it's pretty good, perhaps best for the task.
In the late 80s during development of the CS5, I took on the project of comparing, contrasting, testing and choosing an 'optimum' batting / insulation scheme for the CS5. Such research always trickled down to less expensive products where an as cost-effective. I had some pretty luck help. Toyota was coming to town with their Camry plant. Also IBM keyboard products was down the street and the University of Kentucky had developed a School of Advanced Engineering in support of Toyota's success. I've mentioned the happy quirk that Thiel Audio was a 5th member (of 5) of UK's Advanced Manufacturing Roundtable, to which I was Thiel's representative. Lots of stories there, but today's is that Toyota, of course, was bigtime in the sound deadening business as was IBM. In addition to picking their brains, I brought my cousin Teddy (the GE Jet Engine guy) to the party for his knowledge of aircraft noise abatement. Needless to say, there was horsepower in play. Less likely, is that the scheme we had originally developed in the late 70s won the day.
Many of the reasons for choosing other materials have to do with odor or fungus or handling or airborne particulates. Those issues were all manageable and wool felt and fiberglas is what we kept. There are many new subsequent products and concepts. Thiel never approached constrained layer damping or suspended case in case construction. But we did explore various surface damping schemes. I found nothing to make any appreciable net improvement over what we had. And it seems that future products kept on keeping on. Although I am investigating air movement and panel resonance, I haven't considered re-addressing the original wood felt / fiberglas batt chamber damping. For now at least.
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Yes, indeed - there are personalities who go crazy knowing that each and every day their tubes are getting noisier and noisier . . . and when is proper time to replace them and on and on. Makes solid state easier to love.
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Nice room dimensions.
Don't switch anything until you know if there is a polarity problem.Disconnect the cables at the power amp. Connect 6V battery - minus to black wire and touch + plus to red wire. The coax and woofer should both move out. Repeat on other speaker.
Your symptoms could be created by 1 woofer being polarity reversed.
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Lemming - what's your ceiling height?Are all drivers working? Finger on the cone test.You can check driver polarity with a 6 volt lantern battery. Best test is battery plus to wire at the disconnected cable at the power amp. All drivers should move out into the room.
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that's amp end of the disconnected RED wire.
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JA - recovery was immediate, since re-entry does not say no. I wish I had more time with Rob, but our schedules only overlapped by a couple of hours. We're on firm ground with mutual goals. The trip also included other contacts and prospects. Getting away is good for perspective. Happy Holidays.
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You can use the battery to gauge woofer movement. Are both channels moving similarly with the 6 volt signal?
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Put your preamp in mono if you can. Even if you can't, both woofers should be moving about the same amount.
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GS - you might call Rob Gillum at Coherent Source Service about this matter. Tinsel leads do eventually fatigue, and Rob has replacement moving systems on hand. The little I know about ferrofluid is that there are many types and quantity is critical. I don't see advantage to preemptive repair. I'm still using mine from
1989 CS2.2 prototypes with thousands of hours on their odometer.
Let us know what you might find out from Rob about FF replacement and other issues.
I am presently working on that tweeter via faceplate surface and diffuser modifications. That tweeter was Thiel's first ground-up design which was for the 1988 CS5 (with trickle-down to 2.2 and 3.6).
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Rob,,
Sealing between the chambers is important for impulse integrity. If open, the woofer air pressure yanks the midrange around - not good. You can temporarily seal well enough with Mortite or bowl putty.
When I came to New Hampshire in 1996, we had local long-hair wool production in the village. I looked into it for speakers as a venture prospect. I also read the British, etc. opinions which are widespread and respected. But I was never convinced given my own experience. I anecdotally attribute the "British Bloat" partially to the tendency of wool to decouple below about 100 Hz. Changing batting isn't on my radar, but who knows? We never know.
Wire gauge is part of the resistance equation. All design measurements and listening is done with the selected gauge. But there is another element in play. Skin effect / signal penetration depth is frequency dependent. 18 gauge is optimum for tweeter frequencies. Larger gauges are suitable for lower frequencies. Your change from 18 to 15.5 will add a harsh coarseness caused by propagation eddy currents. What I am doing with Straightwire is replacing the 18/2 with 18/4 in a star quad twist. We keep the optimum skin depth while halving the resistance and multiplying common mode noise rejection - these cables are in an electromagnetic soup from the drivers and crossovers. I am assuming that final level tweaking will be required due to resistance changes. I am applying the same star quad regime along with progressively larger gauges to the other drivers, all with promising results.
Carry on and keep us posted.
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Sdl4 - this is the first time I've heard of one leg being disconnected. They all three should hold the center plug in place. If those tweeters were mine, I would repair them with aluminum filled epoxy. You might consult Rob before doing anything and see what he thinks.
That fore-structure performs multiple functions. It protects the fragile dome. It also spreads the on-axis energy for broader dispersion at the high end. It also acts something like a phase plug in that it retards the leading energy at the apex of the dome to average it with the circumferential energy closer to the surround. The hex shape of the center plate is engineered as superior to a round one.
Considerable effort went into developing that structure, so I find it interesting when various pundits recommend removing it. I suggest trusting Jim's work, those kinds of details represent the meticulous care he took in the design process.
What I am looking at is the sharp edges on the back side of the structure, both the 3 arms and the plug. We didn't address that level of detail in the 80s, but I wish we had, and I now am attending to unfinished business. I do not yet have confirming measurements (working on it), but I (believe that I) can hear improvement via contouring the edges of all members and coating with soft agents. Work in process.
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Just a thought. I suggest running the 3.5s wide open with no EQ. I remember the bass loading as critically damped, so it should approximate 12dB / octave. (But that's old memory) If you can match that rollout with a sub, the sub HF will operate in the directionality range, so 2 subs is better than 1. I for one am most in your progress.
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Jan - thanks for your comments. I am looking forward to including the 2.4s in my queue. They seem to be the audiophile darling in lots of ways, and I hope to calibrate how they stack up with the other models in my rotation. In particular my present work seeks to tame the consistently reported brash congestion with less than best recordings. That problem is not only the recording - the speaker can also be made to handle that situation better.
All - I'm looking forward to what 2020 will bring to these old Thiel classics. Merry Christmas
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jafant - I bought the SCD-1 because it is an iconic product, it had been Thiel Audio's, and it had been upgraded. The few discs I heard on it were wonderous. I'll keep it until I get PS Audio's new PerfectWave player early 2021 and ascertain it does everything I need. The Sony machine is devoid of soft source inputs, which are becoming commonplace these days.
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For the record, wool acts quite differently than fiberglas, as does polyester fiberfill or spun mineral wool, especially in transition to the deep bass. Final placement and voicing of damping was always made by results. Listen to it, and if you have the means, measure the output smoothness. Insulation schemes will unload at various frequencies due to complex resonant behavior, especially in reflex systems. Fiberglas behaves more simply and predictably than any other scheme we found.
In my time, and possibly onward, the first reflection of the midrange driver off its rear enclosure wall was absorbed with dense pure wool felt - it worked the best for that purpose and its considerable expense was worthwhile. Our evaluation of wool batting for absorption was not as good as fiberglas.
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Unsound - I concur with the merit of balanced EQ, and balanced operation in general. I am not the guy to develop that solution; I hope that someday we might find that resource. But the issue of over-driving with "modern" high-impact music and effects still persists. Getting THAT much output from a 10" woofer and 5" midrange with first order slopes is a really tall order.
I'm prototyping a grille that looks stock (for history), but is made of 1/4" round bar outboard and proper roundings inboard. Should be pretty transparent. Also, a properly rounded inboard frame with no outboard element - no fabric, just finish the baffle curves like the CS2.2. Come to think of it, the 3.5 development prototype had just such a half-frame.
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Unsound - I'm not even close to time-lining. I am spitballing lots of areas to establish meaningful measurement techniques, audibility and suitability selection. I can say that the grille is a surprise and is suitable for work - worth pursuing, and that I have 2 first-approach solutions to try. Also, the chosen solution must and therefore will be cost effective. It will re-use the top and bottom wood struts, and the two round steel cross struts. The side frames will be replaced with either Baltic Birch frames with more complex, angled routed openings and steel reinforcement to allow contouring of the inboard (baffle-side) member. Or the side frames could be replaced with steel round-bar frames. New, more transparent fabric in either case.
If you or someone you know is handy with such things, I could tutor you through the considerations and you could DIY a solution or two for our mutual edification. Otherwise, I suspect sometime in 2020 with a justifiable and reasonable price.
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Unsound - I'm not in a position to manufacture new frames, but we'll work on getting yours hotrodded.
Catalysis - Thanks for your kind words about the CS3.5; I'm confident that we can upgrade some of the weak links in them. From a historical perspective the 3.5 represents Jim's pure vision, before HT, Digital sources, etc. demanded ported bass or more elaborate and expensive solutions than we were able to shoulder. Remember that Thiel was only 5 years out of the garage and 7 years total in its start-up. Regarding fruit, it's looking like the CS3.5 is my first project (with other models as lab rats and workhorses as supporting cast.)
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And I am pleased with upgrade progress in the studio.
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Strindl - I love your system. I also resonate with your musical tastes. I believe it worth saying that your desire to derive meaning from your music was at the very heart of the Thiel Journey. What we struggled to find and execute was a vehicle for connection. For Jim the focus was the musical web. For Kathy and myself the lyrical realm mattered as much. Walter tuned in to the drums and rhythm and Fred went right to visualization and the out of body experience. The communal aspect kept the dance alive full-time.
As time went on, those intangibles took a step behind the relentless work of continual developments and growth. But the founding value of access to soul by musical journey remained in the products’ DNA .
My present renaissance work seeks to hold sacred that goal of connection. I find a joyful dose of contemplation in the systematic discoveries every day.
My hope is that the meaning and message in your music will become even more accessible and real through the next generation updates. |
Andy - the debate hinges on the criteria for superiority. The mainstream represented by Mark Mason include some aspects at the exclusion of others. Jim’s approach was that everything matters. |
Mr Bill - the CS1.7 is a real pot of soup. It represents the final battle in Thiel's hope for survival. I have patched together the story from reliable insider sources and first-hand evidence, and here's the thumb-nail. The 1.7 was codeveloped along with the 2.7 by Kathy's home team and the Canadian consultants previously outlined in this forum. The 2.7 was introduced in the fall of 2012 as a re-statement of Jim's design goals by his surviving company. The 1.7 was being readied for introduction at January 2013 CES, after the purchase by New Thiel. They pulled it for Mark Mason to "design a better speaker" on the 1.x platform. The resulting 1.7 had a more robust tweeter and 4th order crossovers. An argument ensued as to whether they could-should call it a "coherent source", since they owned the trademark; but the loyalists insisted it wasn't a coherent source, and I concur. Heads rolled the Dawn and Gary and Steve DeFuria and Bob Brown (the leading loyalists) got fired. Lana and Rob kept their heads low and stayed on. And the circus commenced which led to the liquidation bankruptcy which is still incomplete.
Stereophile stayed out of it and didn't review the 1.7. I have seen no other reviews. I know the cabinet was beefed up. I know the tweeter was improved - quite good I understand. The slotted port is the same as the 1.6 and the woofer had been developed by old Thiel. The 1.7 as introduced has a smoother frequency response and it handles more power due to the 4th order slopes. Its anechoic tonal balance peaks at 100Hz and falls about 6dB to treble, so it's balanced like a B&W rather than flat like a Thiel.
In the world of magic and speculation, interested loyalists might acquire the few extant pairs of 1.7s for later conversion to the 2013 first order crossovers and have a final tribute to Jim Thiel's design legacy. If I live long enough or am able to create a successor organization, I would relish that possibility. In the mean time, the current CS1.7 is a bit of a hybrid, mostly Thiel with a core dose of PSB/Mark Mason/New Thiel crossover slopes, which by world standards is what is expected in a modern speaker.
Happy New Year and New Decade, all
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I like Beetle's perspective, and the two factors are fundamentally linked. Early-on, I wanted to work toward an ongoing entity that would transcend any and all founders' contributions. Jim disagreed. He wanted a vehicle to support his research and development ideas. "And when I'm finished, it's over". That stance caused the lack of successors to his chops, which in turn caused the lack of interest from qualified buyers, since history is but a small fraction of viability. An extensive multi-year worldwide search turned up NO qualified buyers. The denouement was thoroughly predictable because it was embedded in the company's genes.
The paragraph above is a short snippet of a 40 year scenario that was quite difficult to live through. A company, even a small entity like Thiel Audio, orchestrates significant life events and outcomes for scores of people spanning dozens of years. A primary motivation for my re-entry into this story is to soften some of the rough edges of the company's trajectory.
To Andy's point: New Thiel demonstrated quite clearly how a marketplace responds to non-focused strategies. New Thiel spent $10Million trying to do the standard job really well. Their tower speaker got 5 stars from Brent Butterworth and did the standard thing at least as well as X,Y and Z. But who would buy a Thiel Standard, when you could buy the real X,Y or Z Standard from PSB, B&W or anyone else in the field. Primary among the reasons we chose first order slopes is the uncanny rightness of sound, which I have previously addressed in this forum. For those who "get it", there is often no going back. Count me in that camp in company with many of you. Another reason was the extreme difficulty. By the time of the 03 and 04 in the late 1970s, there were companies (Japanese and European) buying them for competitive evaluation. I, as external affairs liaison, would follow up those encounters. Frankly, we were afraid that companies with comparatively unlimited resources would take our ideas and leave us in the dust. A senior executive at Dynaudio relieved our angst by saying: "What you are doing is impossible, expensive and invisible. Don't worry about others trying it." He was right, and we changed stragegy from patenting innovations to running as fast as we could on our own course. That seemed worth doing, and still feels good.
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Dynaudio was a close, interactive supplier, and lots of mutual respect developed between us. No put-down intended. The point is that we did our thing.
Regarding viability: companies form around and live their goals. Ours was to make musical tools that mattered. FYI: Thiel’s demand was always beyond its ability to produce. In the first 20 years, that growth was a huge burden. Later it became a choice. 50 people is a manageable number that allowed innovation and large enough scale to pay the bills.
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Altx - your CS2s are early.. You might consider talking with Rob Gillum at Coherent Source Service about an update that addressed the upper midrange. CS2 was most popular model ever.
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I know audiophiles don’t admit physical aesthetics. But the 3.6 and 3.7 are as different as it gets in the Thiel line. Another thought is that the 3.6 drivers are completely Thiel design and build. OK the tweeter was assembled by Vifa, but it’s all-Thiel, unlike the 3.5 which were modifications of normal, pre-FEA era. |
sdecker - regarding the 2.4 vs 2.7, I can supply some contextualizaion and personal observations. I don't know either speaker well, but I heard both in September 2012 when the 2.7 was finalized, although our working comparisons were between the 2.7 and 3.7, which is a different story.
I think the 2.7 is an extraordinary speaker, but built and priced by a different standard than Jim's ethos. I also think that it veers away from the traditional role of the model 2, which was the svelte little sister to the model 3 big brother. The model two had always used a smaller diameter midrange than the three, along with the smaller woofer with higher crosspoint - resulting in less doppler distortion, lower inertia, and a more nimble, lithe personality for the model 2.
The 2.7 was developed under different circumstances and therefore different rules. Thiel needed a new product after Jim's death to demonstrate that they could produce a credible contender without him. I say it is a success, but not the same contender that Jim would have designed, because Thiel no longer had his considerable chops and long-range vision. Jim was working on a CS7.3 with a new, improved coincident, passively coupled high driver. (The CS7's high driver was developed in the CS2.3). That 7.3 high driver would then be tumbled down to the 2.5 - the way Jim Thiel did things. All those plans went on hold when Jim died and a successor engineer or company was not found to carry the torch.
A far simpler and executable fall-back plan was to take, as you mentioned, the extant 2.4 bass system including the woofer, passive and enclosure volume and mate it with the extant 3.7 wavy high driver, making XO changes to accommodate. One circumstance is that the higher woofer to mid crosspoint necessitates a very large capacitance coax feed. The 2.4 has 30uF feed capacitance and the 2.7 has 416uF, including a 400uF electrolytic. That's the only electrolytic feed cap since the 1976 model 02, as far as I know.
So, yes, the CS2.7 is a valid Jim Thiel tribute design with first order slopes, minimal diffraction and lots of learning rolled in. And it is good. Some forum members here and elsewhere choose it over the 3.7. But it is in some ways less elegant and demure than the next model 2 from Jim would have been.
Enjoy the ride, wherever you go.
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Rob - I will be most interested in your 15.5 to 17.5 gauge comparison.
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It's probably caulk - I don't know what kind. In my time we used acrylic latex painter's caulk with good results, and sometimes hotmelt adhesive to build a mound. But, sealing was always be a big hassle; hotmelt and caulk are both permanent, which leaves few options when a leak develops. so I am experimenting with something else. Permatex type II non-hardening sealant from the automotive store. It softens with heat for removal and resealing. I'm working the Ptex between the wires, putting a Mortite dam on the bottom / outside, and adding a Ptex mound inboard, then hitting it with hot air to settle it. So far, so good.
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sdecker - you are asking the right questions. And I have no answers. Remember that I had no involvement or insider information from 1995 to 2012. I'll tell you what little I have pieced together. Please pardon any repetition for the long term readers.
Thiel created the CS2.7 to develop and demonstrate their ability to produce valid products without Jim. They auditioned multiple inside and outside engineering solutions and landed on Warkwyn - Toronto, a full service design development firm with full access to the Canadian Research Center which develops most of the Canadian brands' products. The concept design was developed by Home Team Thiel, and Warkwyn did the engineering and prototyping. The results were not acceptable to HTT, and that process went on for a couple of years and cost mid $six figures. I got the impression that engineering decisions, such as you iterate above, were not on the table for discussion for reasons I can only speculate.
I will say that Jim never used a cap larger than 100uF, even in parallel circuits. I will say that Jim was very cognizant of beaming and its power response implications. And it seems to me that the core personality of the 2.7 became conflated with the 3.7 to a much greater degree than previous model generations. The 3.7 was designed to play louder into larger spaces with deeper bass; whereas the 2.7 was to be more intimate in smaller spaces with less bass extension to not distress those smaller spaces, at considerably reduced cost. Such gestalt overview seems to have suffered as time went on - the 2.7 / 3.7 seem far more similar to me than the CS2 / CS3.5.
Your suggestions above seem well considered to me. I wonder with you why such basic considerations didn't make it into the product. Notice that there is a convenient slot of 2.5 - 2.6 in the line-up. Who knows what the future might bring?
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Correction: In the second last paragraph I mis-typed 3.7 and 2.7 where I meant to say that the model 3 was designed to play louder . . . and the model 2 was to be more intimate . . .
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Warren - I lack the direct comparison of SS2 vs SS3, but can share some relevant experience. I have one SS1 and two SS2s, which I have mixed and matched and moved around. First, my room is weird. It is my guitar-making and music studio and speaker workshop rolled into one. Its acoustics are good, but unusual, so YMMV. In the corner of a second floor residential-construction building with 12K cuft with open stairway connection at far corner to identical space below and smaller attic space above. Lots of volume. Playback is intelligible anywhere in the whole envelope. The studio walls enclose 3600 cuft in an L with front and left exterior walls solid and other walls porous - non-reflective with lots of diffusion. Virtually no room modes. Speakers in the assymetric L corner, listening in the 15’ wide top of L. It’s weird, but it works and presents neutral sound and smooth measurements.
In this context I have experimented with Thiel subwoofers.
SS1 between speakers and in solid corner (front left). Thiel PXO sums R&L channels. Dedicated XOs for PPoints, CS1.6, CS2.4 (used with my CS2.2s) and CS3.6. The PPs and 1.6 are substantially upgraded by deep bass. The 2.2s and 3.6s additional deep bass is nice, but not musically necessary for me. Same speakers with pair of SS2s. The musical experience is qualitatively improved with all speakers. The art of mixing includes collapsing to mono without cancellation, but that business is difficult and approximate at best, as Unsound noted. Note that using a pair of subwoofers driven by a single PXO was substantially inferior to using a pair of PXOs, one for each channel, which keeps the bass information of that channel with the speaker for that channel, as Unsound observed above.
Regarding replacing an SS2 with SS3, I believe the only reason would be if your space / loudness requirements are overloading the SS2. I don’t overload my SS1 in the corner (best coupling) at robust loudness levels into an effectively huge space. Any model SS's low frequency extension is lower than musical content for all practical purposes. My experience is that a pair of SS1s or SS2s with 2 PXOs provides a highly satisfying musical experience for 2 channel music. I plead ignorance of HT .1 channel.
Note that someone here previously reported a big step up by using Thiel’s Sub Integrator whereby you can tailor a sub to woofer crosspoint at a higher frequency and custom slopes. I want one, but haven’t seen any on the market. Perhaps your Marchand might provide that function. I consider all of these options as more satisfying than going to an SS3, UNLESS you have a very large room, listen at loud levels, and are running out of steam with the SS2. I vote that two SS2s in any placement driven by two separate PXOs would be worth an audition.
Enjoy,
Tom
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FWIW - I think the SS2.2 is a post Jim Thiel alteration , much like the CS1.7 was. Does anybody here know if the SS2.2 has the room boundary compensation.? |
Warren- wow. Let us know how this venture unfolds. Are you a closet headbanger? |
Correction: I have read that the SS2.2 was introduced when Kathy was still president, so it would be an update of Jim's design. The conversation and questions I am remembering must have come later in the game.
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Unsound / Warren - a woofer designed for sealed box loading is a different animal from a ported unit. What you propose is very interesting to me. I would like to take a 3.6 and replace the woofer for a sealed box loading to make a super 3.5. That would be a worthy undertaking in my estimation.
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Unsound - I believe that the wavy driver completely eliminates lobing at its cross point, leaving only the lower cross point to lobe. And the 3.7 lower point is so low that beaming is quite minimal, so the on and off axis response is effectively very similar, leaving only on axis ear height as a constraint, which is easily solvable - sit on a couch or easy chair. The flat wavy disc practically solves the hollow tweeter launch environment. Can you tell that I’m a fan?
My main reason for addressing the older models is due to their geriatric needs, the large quantities, and the greater room for improvement. |
Robrink - 02A doesn't sound like a Thiel model. Can you tell us anything about it?
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