Thiel Owners
Tom and Dsper I began my Audio hobby in 1950, and was a devoted tube guy until the quality of KT88s and other amplifier tubes went South. If I wanted a matched set of 88s (or other final tubes) I had to spend a minor fortune (for me.) Switching to solid state was both a monetary and aural decision. I got so paranoid that I hated tube hum in my system. |
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"Acoustic Suspension" is a distinct variation on "Sealed" and I’m still not certain why that went so entirely out of favor for ported designs nearly universally decades ago. Make the cabinet a little bigger, power through a couple dB less efficiency, use a bigger woofer (or two), and get cleaner bass that rolls off at 12dB/octave instead of a ported 24dB/octave for far greater real-world extension without any phase shifting. With modern cabinet and cone materials and motors, I can't imagine a larger-diameter AS woofer with less excursion wouldn't play as loud with less distortion than a smaller ported woofer trying to move that much air though excessive excursions. I had two of the best examples of AS prior to Thiels, but there were so many apples vs oranges the lower and percussive bass response was merely ’different.’ |
Pretty much all speaker designs are a balance of trade-offs. If there was a perfect formula then all speakers would implement that design. Sealed bass enclosures are generally considered to sound the most accurate and that is certainly what I hear. But sealed boxes are limited in extension and ability to play loudly. IMO, Jim Thiel’s passive radiators are a bit short of SOTA sealed boxes in terms of quality (think CS5, for example) but nevertheless are a highly satisfying solution, especially at their price point. |
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. |
i just purchased Thiel CS6's and yes i hear a huge difference when i flip the phase. I use my Sonic Frontiers Line 2 preamp to do this. I would guess its because the passive radiator is inherently our of phase with the rest of the signal. when the woofer cone moves out to create a mid-bass hit the passive radiator must move inwards. and i think the speakers were designed so that the natural physical crossover between the woofer and the passive radiator is at a common junky room resonance node (so he could hide the absence of some bass). When I flip the phase I like them better because the low bass hits first, but you will then encounter one resonant room node in your upper bass. And it makes the stereo image recess instead of come forward. They would be insanely amazing if they had actual cones driven for the low bass. |
Last weekend I had the chance to visit Glenn Poor's Audio and Video in Champaign IL, had some questions about my BAT VK-55, and luckily Geoff Poor was in the house. I told him about my set-up, he said he sold Thiel back in the day, loved their speakers, was complimentary of my amp/speaker pairing (salesman alert!), and then, unprompted, he offered up that "most people don't remember, but Tom Thiel was a true craftsmen, the fit-n-finish of his cabinets were always superb, and what a lot of people don't realize is the enclosure and cabinet design and manufacture was a good part of what made the speakers sound so good." Then he had me listen to some new Quads and I was blown away, even with the flash-drops. Enjoy your weekend listening to music! |
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. |
@sdecker My analog section is decent: Kenwood 500 (direct drive) mounted with BenzMicro ACE, tonearm wiring replaced with Cardas feeding an Ayre P-5 . . . But I almost never use it. Until this week, I hadn’t used it at all since probably last winter. 24-bit files sound superb through my DAC, all the textures of vinyl combined with the dead silent digital background. Best of both worlds. I am planning to try Tom Thiel’s solution but probably not until after my “new” DAC settles in. Thanks for your observations about the baffle morphology on the 2.3 v 2.4. Very interesting! I’m motivated to experiment. |
I've never been certain how the 2.4 steel frame grille plate affects the diffraction 'problem' as it tightly surrounds the coax with 3 cuts at about 20 degrees, 0 (vertical), and 30 deg. But the steel still presents as an edge, a discontinuity, for the coax wavefront. It is just closer to the coax than the baffle edge when the grilles are off. If you removed the grille cloth off the steel frame, it would more-clearly visibly *appear* to be problematic wrt 90 degree discontinuities closely around the coax. I'm happy to entertain the soundstaging differences are from something unrelated to the baffle differences, which appear to be such an obvious contributor. I've had my 2.3 coaxes in my 2.4s for extended periods waiting for replacement 2.4 coaxes, but beyond an interesting change of frequency balance, couldn't discern any soundstaging differences... |
Fellow Thiel-ers. RE: 3.5's and amplifiers. Just a post for whatever it means to you. I've replaced a series of SS amps with a pristine used VTL ST-85 (paired with a Counterpoint SA-1000 preamp and a Counterpoint SA-2 headamp. Magic! This amp is much better than the Audio Research D90b I used to use with these speakers (before the SS's.) The 85 is optimized for 5 ohms, exactly what the 3.5 needs (impedance 4 ohms to 6 ohms over most of its range.) The amp is rated and delivers 85wpc at that impedance, and has an absolutely flat power response down to 20hz according to the QC chart that came with mine. Bass of course is not equal to the SS's, being less controlling and tight. But oh my, the naturalness and 3D of these pieces even with less than optimum speaker environment is superb. And the power is sufficient to have normal listening levels in the next room when I am working at my computer. BTW, the VTL also sounds superb with my 2 2's which are even more transparent, but I was expecting that. It is with the supposedly power hungry and "veiled" 3.5's that the surprise happened. As I sa id, make of it what you will. |
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. |
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. |
@andy2 That's exactly my concern, problematic diffraction effects for the sake of "aesthetic appeal" fly in the face of all I came to know of Jim Thiel's design ethic. And yes, he was alive and kicking throughout the CS2.4 project. @beetlemania If your analog front-end is up to par with what I read earlier of your amplification, it would seem vinyl would be at least the equally-good source for critical listening! I guess I'll be paying a visit to a tailor for the first time in decades (!) to try some of these materials. Perhaps I could just put the felt around the coax's metal perimeter, up to the surround, as there isn't enough space to mill out the grille metal to the left and right of the coax baffle area. That would seem to defeat the idea though, as I'd be attenuating all the coax output that isn't straight-ahead, vs allowing it to freely disperse unobstructed. Which takes me back to the compromised 2.4 baffle in its entirety of construction :-| |
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. |
@twoch I've done tie-dye once but fail to see how that is relevant to this thread. @tomthiel @sdecker OK, you now have me very curious to try a baffle treatment. But my DAC is away getting an upgrade (I'm currently rediscovering my LPs), so I'll have to let that settle in before I can do a fair test of changes to the baffle. |
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. |
@tomthiel Sure wish I could post images directly. Doing a google image search on the speakers in question will produce a few with the correct angle to view the issue at hand, below. The 1.6 (and 1.7) are similar to the 2.4 about my concern of the recessed baffle. The 1.5 is a very different mounting strategy from the 2.3. The 2.7 baffle is again different from both the 2.3 and 2.4. I will play with your felt solution with my 2.4, but in their case, this will disallow use of the grilles w/o some klugy modifications: most of the grille weight is supported by a pin above the coax, requiring the grilles remain flush against the baffle; the magnets help support the grille perimeter. In my home, the grilles must remain on. Here are quick and dirty links to reasonably good views of the 2.3 and 2.4 baffles: https://www.alibaba.com/product-detail/Thiel-CS-2-3-Hi-End_11195163.html http://www.hifi4sale.net/t38695-thiel-cs-2-4-used |
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). |
tomthiel, "...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..."Tom, please bear with a couple of basic questions: 1. Reducing hiss then, is around acquiring quieter components in the chain. This would then also reduce the noise floor and allow more detail to be heard? 2. If I want to check if I have CS5's or CS5i's, I simply unscrew one of the woofers and look at it? Thanks for your advice! Dsper |
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. |
the 630V caps and far-more-expensive Mundorfs et al were simply too big for the space on the XO boardThe higher voltage versions, with thicker film, are reported to sound better. I didn't compare different voltages on the coax feeds but did directly compare 160 and 250V versions on the woofer shunts. Some say that shunt cap quality makes little, if any, difference in SQ but, to my ears, the higher voltage version sounded a bit more relaxed and with more bass heft and impact. A subtle difference but one I am willing to pay for. In my case, the larger caps were not an issue because I started with completely new boards/layout. So, no need to fit a new cap into an existing space. |
Thanks for your post, Tom. Interesting that Rob found the ESAs to sound worse. My experience was that nearly every change improved the sonics. Perhaps because I had a good coach ;^) I am considering those electronic upgrades as end of project decisions. My focus is on re-bracing and re-baffling which is progressing well.As you know, I'm a big fan of upgrading the passive parts. And I think a lot of the improvement I hear can be had for less money. That said, I'm looking forward to trying your baffle treatment. |
Hi All, I have a couple of CS5 questions for the Thiel experts. 1. how does one determine if they have CS5's or CS5i's? I read somewhere, I think on this thread, that there is no marking on the outside of the speakers to tell? My serial numbers are 1225 and 1226. 2. When I turn my system on with the preamp allowing no volume, I can hear different sounding "hisses" from each of the three small speakers on the top. This is audible only with my ear within six inches of each speaker. Is this normal? Or is it a sign that something is wearing in the crossover, etc. Or could it be coming from another piece of equipment like a tube preamp? Thanks for listening, Dsper, |
