Thiel 3.7

Thanks Unsound for alerting us. I've held off doing anything about upgrading my 2.2's for this long largely to wait and see what JT did with the 3.7. The last time I spoke with Shari about it he supposedly had just begun to sit down with the proverbial blank sheet of paper. I strongly suspected the new iteration would have to include some clear advances/evolutions over all previous models, and wondered how he could do that while still slotting the thing under the 6- and 7-series models. This model looks to address a couple of fundamental issues that I've been hoping Thiel would get around to in the next generation of new products, namely:

1) Continuing to utilize coincidental mid/tweeter geometry to reduce frequency lobing and expand the listening window, while moving to extend HF dispersion by getting the tweeter out of the horn-like concavity of a midrange cone (I believe only the 7-series has addressed this in the past). I'll be honest: my prefered theoretical solution was to see a mid/tweeter dome arrangment, with the two drivers forming a continuous-profile dome with the motor assembly, made small by the use of powerful rare-earth magnets and Thiel's shared voice-coil technology, placed within the dome. (Just picture it as a sonic breast with a nipple in the middle :-) I feel a dome shape for the midrange diaphragm must be somewhat stiffer (as is a cone) than any corrugated flat profile like was adopted here (not that you couldn't corrugate a dome as well for even greater stiffness), and also that a dome offers the widest dispersion for both mid and tweeter. This is not without challenges, since the whole driver unit would project forward of the baffle which is somewhat unusual, and achieving time-alignment with the LF drivers would then require a greater baffle angle, but only if we're assuming Thiel's traditional baffle arrangement paradigm, instead of moving to some sort of "baffleless" situation of the M/T driver, which may be inevitable down the road anyway.

2) Moving beyond the company's previous cabinet design, which, despite the angled and contoured baffle that was something of a watershed back when first introduced, continued to employ a traditional square-backed box made of MDF. The new model's rounded aluminum cabinet top (ending closer to the height of the M/T driver rather than extending higher up as on previous Thiels) and what looks to be a parabolic contour to the cabinet rear, were in my estimation the kind advances required if Thiel was not to fall behind some of their competitors in the area of modern cabinet design and appearance. Although I've never been crazy about the idea of resorting to 3" thick MDF for the baffle from the standpoint of internal diffraction (especially around the midrange driver -- I find the thinner, non-MDF cast baffles of Thiel's upline models to be a more elegant solution to the rigidity issue), positioning the M/T driver nearer to the cabinet top ought to provide image height/openness benefits, and the contoured back should be much stiffer/less resonant (and possibly reduce internal standing waves, though my own hunch is that other manufacturers of similar cabinet shapes may be overhyping this aspect to a degree). It also seems to look pretty good (not great necessarily, and maybe a little derivative -- natural convergence could be a factor here -- but I'll wait to see it in person), even if you can't any longer place an album jacket temporarily on top of the speaker! (I'm assuming this cabinet must also be shorter and deeper the the old design.)

I'll be interested to learn a few other things (and the price of course), such as whether the 3.7 uses a separate or shared voice-coil arrangement for the M/T driver (shared would've been my assumption, but then I'd expect the promo lit to trumpet it), where the crossover points are, how exactly the cabinet is formed and of what materials (I'd like to see horizontally stacked, die-cut ply for the back and sides if we're staying with wood, but suspect it's a ribbed and bent MDF/veneer laminate for now), and where Thiel will next take these new approaches with the remainder of the model lineup. Some other random observations:

The corrugated aluminum cone drivers remind me a bit of those used in Energy's upline speakers.

Thiel continues to favor aluminum, extending its use into the cabinet area (hardly a novelty, just new for them I believe).

Thiel doesn't yet abandon the use of wood structurally, along with an overall wooden furniture appearance. I do think this is an intermediate step, and that in the not too distant future all manufacturers serious about competing in the area of cutting edge cabinet design will have moved beyond the speaker-as-wooden-furniture paradigm, as several already have. This is usually not done without a cost penalty however, and I'm aware and thankful that one of Thiel's priorities is to provide a decent value.

I see that the 3.7 still adheres to placement of the active LF driver rather far down the baffle, near the floor and well below ear height. In most speaker designs this is not a problem, given where the crossover point is typically located and its slope. But in Thiel's 3-way designs, the LF crossover point is usually at least in the middle of the midrange (I believe anywhere from 600 to 1kHz depending on the model), and combined with the slow 6dB-per octave roll-off of a 1st-order design, this means that the large driver is putting out significant sound well into the upper mids. I know that with my 2.2's, which cross over at 800Hz, I find that having a driver responsible for that much of the midrange placed as low as it is, and spaced relatively far from upper midrange and HF drivers, can lead to what I perceive as a bit of "vertical discontinuity" of imaging and an unrealistically lowish image height for many instruments and vocalists.

To that end, I wonder if maybe the next generation of Thiel's 4-way model could feature a triaxial LM/UM/T arrangement (I think only Cabasse does this now, and they do it as a dome which as I said does appeal to me). In any case I would like to see Thiel pursue increased symmetry of radiation from the lower midrange and up in their floorstanding models, whether by going triaxial or employing some sort of D'Appolito-inspired symmetrical driver array in combination with the coaxial units, as they've done in a stand-mount design.

Thiel has not yet jumped on the more-exotic-than-aluminum tweeter or "super-tweeter" bandwagons.

I find it interesting that the passive LF radiator is now a corrugated aluminum cone instead of the previous stiff-core foam flat, and wonder what prompted the switch and what the sonic benefit is supposed to be.

I also wonder where the introduction of this model leaves the 6- and 7-series models. If I had to guess, I'd say the next-gen ones could feature some of Thiel's "SmartSub" technology built into the speaker and more extensive structural use of aluminum.

Ultimately I also wonder if/when Thiel will follow their overall sonic aims to what would seem to be their logical conclusion and make an entire speaker system that utiltizes line-level crossovers and multi-way amplification (perhaps digital, perhaps outboard, perhaps sat/sub) to better achieve their design goals without the limitations imposed by the traditional passive onboard crossover/component amplifier approach...

Hi Unsound, thanks for the greeting, nice to talk to you again too. I don't post much here anymore, except for sometimes when one of my old threads surfaces, and hardly ever look at the new threads these days, but every once in a while I do and just happened to catch yours -- lucky for me. Allow me to comment on some of your points:

"I like your thinking regarding a multi-dome MT. I suspect the biggest problem for Thiel would be maintaining correct time domain. I supposed an electrical (digital?) cross-over could compensate for that."

Actually, this is no problem at all in the analog domain if Thiel's shared voice-coil design is used. There can be no time-alignment discrepency between a single voice-coil and itself.

[This brings up a little side matter: I take exception with Thiel's terminology referring to the 2.4's M/T arrangement as a "mechanically crossed-over" multi-way driver, although I understand completely why they do so from a marketing standpoint. But the 2.4 isn't really a 3-way speaker at all -- it's a 2-way equipped with an upper driver able to shrink its radiating diameter with increasing frequency. There's only one voice-coil up there, two voice-coils in the speaker as a whole, and only one division point in the electrical crossover, ergo it can't be a 3-way speaker. (If the "upper crossover" were really a crossover, then the tweeter dome would be fed a high-pass-filtered signal.) The potential disadvantage to this arrangement (compared with real 3-ways) is that the HF driver is seeing frequencies well below what's typically fed to a dome tweeter (only about -6dB at 500Hz or so), therefore the issue of possible Doppler distortion of the higher treble may be raised. The benefit (compared with other 2-ways) is that the much lowered true crossover point means the LF driver is relieved of responsibility for the upper midrange and can therefore be made larger and go lower than is normally possible in a 2-way design. Personally, I think Thiel should have taken a stab at marketing the thing as a unique 2-way instead of a psuedo-3-way -- audiophiles like the idea of 2-ways -- but maybe they thought consumers would interpret that as being a regression carrying a higher price tag. Instead JT's talked about how the 2.4's design gives consumers a high-quality, wide-range 3-way at a price not much higher than what they might expect to pay for a good 2-way, and -- even disregarding the fact that there are $20K 2-ways and decent $2K 3-ways out there -- this tends to ring a false note with me. I think profit margin has a lot to do with the implentation of the "mechanical crossover" -- not that that's necessarily a bad thing, just something I wouldn't be loathe to admit as long as the sound quality justifies using it. But let's be honest: He managed to engineer a solution that eliminated one whole driver and half of the crossover network while maintaining high performance. It is ingenious, that's for sure.]

"From what I understand the drivers are corrugated to suppress resonances. I've heard claims of 0 (that's what I heard ZERO) unwanted resonances from both mid and tweeter to 22kHz! This may set a new standard for dynamic driver sweetness."

If true, the 22kHz figure would be quite a high first resonance point for a midrange diaphragm, but nothing at all to write home about for a tweeter, just the minimum allowable to my mind (many aluminum dome tweeters go a few thousand Hz higher before breakup -- in fact I'd be mildly surprised if this one didn't as well -- and some of the newer exotic domes are supposed to go twice that high). Anyway, in this case of the corrugated diaphragms, talking about reducing resonance and increasing stiffness are really two ways of talking about the same thing (as opposed to talking about reducing resonance through application of increased damping).

"Regarding your thoughts on the thinner baffle, many years ago I asked Jim Thiel why he didn't use a pyarmid shaped cabinet to reduce baffle width in accordance with driver size. He responded that he would prefer to use a wider baffle but was concerned that the market would object to a bigger speaker profile. He thought that having a wider baffle would offer more support for the drivers and the he could control dispersion better for the consumer, as the first reflections could be designed in rather than being dependent on the variances in consumers' rooms."

Here I think we're getting confused between what I was talking about, which was baffle thickness, and what you're talking about, baffle width. A 3" thick baffle restricts what kind of environment you can present to the rear of drivers mounted on it, and affects midrange drivers most. Speaking of baffles, I'd also like to see Thiel take a shot at covering theirs in a sound-absorbing material, at least in the vicinity of the upper drivers.

"I also share your concern about the woofers being so far from the other drivers. I suspect this arrangement mandates a farther listening position from the speaker for proper driver integration and less freedom to move about during listening. Perhaps the large distance does allow the bass driver to appreciate room loading better and may offer the critical mid range and in this case in particular the tweeter some more isolation from the woofers vibrations."

I doubt that the height the woofer is mounted at was influenced by, or has much effect upon, how its vibrations transmit to the other drivers. Of course being mounted closer to the floor could have advantages for the bass, but unfortunately that's not the only frequency range handled by the LF drivers in Thiel's 3-way designs. The listening distance is dictated not just by the driver spacing, but also the baffle angle, and the greater spacing allows the angle to be closer to vertical. One way around this to use stepped, rather than angled baffles and drivers. Personally, I have found the angled drivers on Thiels to contribute, along with the low positioning of the drivers in general, to a kind of "looking down into the soundstage" perspective unless you sit well away from the speakers.

"There have been rumours about a very expenisive flagship model that might be omni-directional."

It seems JT has been torn about whether to build a $$$ flagship for years. I think he'd like to try and see what he can do, and knows what kind of cache these things carry in high-end circles for better or worse, but I also get the feeling he's philosophically sort of against cost-no-object extravagance at the same time, both as an image thing and also from an engineering standpoint. Besides, it would divert resources from building products that more people could buy and own. But that such a speaker coming from Thiel could ever be omnidirectional is indeed news, even if it never gets made -- I thought he was dedicated to monopolar radiation in principle, at least as a practical matter. I wonder if he's considering use of horizontally-mounted drivers and acoustic "lens" reflectors a la that B&O speaker (not truly "omnidirectional" in the vertical component, but capable of being made time and phase coherent).

Hey! What happened to the old Shari?? This can't be good...

Looking closely at the photos on the website, I don't think the new compound driver uses the shared voice-coil design. It seems to have two adjacent inner suspension gaskets, one for the tweeter dome and another for the midrange diaphragm.

(Also, I'm thinking that passive radiator looks as if it's going to be a sore point for survivability problems with kids/dogs/vacuum-cleaners unless they provide some sort of screen for it behind the grille...)

Hi Dan, thanks for the info, you're another one I haven't communicated with in too long. I saw a thread recently about phase- and time-accurate designs where you mentioned you've moved on to Harbeths and are well pleased (I almost contributed to that thread too, but decided it would take too long a lecture to disabuse the Hardesty-clone true believers that what they hold so dear isn't as cut'n'dried as they idealize it). I never was convinced you were satisfied keeping the 2.4's, respected them maybe but not in love...feel free to elaborate :-)

LOL. (BTW, did you ever decide that you liked the 2.4 as well as you had the 1.6?) As for me, I think my main "issue" with speakers is what I would call trust: Whenever I hear a speaker that makes a certain disk or piece of music sound unusually great, I typically find that it isn't telling the truth and will be correspondingly not-so-great on other music or disks (not saying the Harbeth is this way - I don't believe I've ever heard a Harbeth, and anyway I thought they were supposed to be fairly "neutral" as the saying goes). I feel comfortable that the Thiels are pretty reliable messengers which I can trust, but at the same time realize that there are certainly aspects of the sound that my (after all relatively modest) speakers aren't capable of fully expressing (mainly having to do with the rich body, physicality, dynamism, ease and sweetness of real music). But I can't, unlike many audiophiles, be happy switching speakers often -- I need a consistent point of reference, and besides I'm also a cheapstake who isn't pursuing the SOTA. I started building this system by choosing my Thiels in '97, and have only recently really begun to think that I (and the rest of my system) might be ready to contemplate taking another step, which if/when it happens I presume would be "for keeps" for even longer next time...

Anyhoo, I've been thinking about the midrange driver on that 3.7, and it's occured to me that it might well not be driven at the inner or outer edge of the diaphragm, unlike typical cones or domes. The coil former might be attached at the center point of the ring, midway between the suspension surrounds, giving the diaphragm added rigidity by taking the form of a "T"-shaped cross-section. This would make a lot of sense in combination with the radial corrugation of the diaphragm visible in the photos, and very possibly indicate the kind of lightness and rigidity implied by the high first resonance point figure quoted by Unsound. (Lighter than could probably be achieved if the center-driven diaphragm projected forward in a similar-sized semi-toroidal ring, partly because the former itself can be made very short with the flat diaphragm.) If the flat corrugated ring is indeed center-driven, that would be one explanation for why the compound driver doesn't use Thiel's shared voice-coil technology. The only thing about this conjecture is that the driver is described as being 5" in diameter, which would make for an absolutely prodigously-sized voice-coil width-wise, though presumably very shallow in depth.

Danhirsh: That's a pretty expensive list of speakers you feel the 7.2 is better than :-) I wish my memory was as good as yours -- I can't remember what we talked about "some years back", but I'm glad to learn my credibility has survived it! Seriously, it's clear you've heard a lot more speakers than I have, so I can't imagine what I could've informed you about concerning Thiels, but your high estimation of them in such company as you've mentioned says more than I ever could.

If anyone cares to visit the ELAC speakers website and click on the 600 series under "Products", then click on the photo of the cutaway coaxial mid/HF driver (called the "X-Jet"), you'll see a view of a ring-diaphragm midrange design I'm guessing could be not dissimilar in overall concept to what's in the 3.7. There are obvious differences of course: the ELAC uses a honeycomb-sandwich diaphragm, is only 3" in diameter, and the tweeter it encircles is not a dome, but a Heil Air Motion Transformer variation. However, this picture does illustrate the type of centrally-attached voice-coil I'm hypothesizing might be used in the Thiel driver. (Oh and BTW, floorstanders featuring this compound driver from the German marque, intriguing as it is, are unfortunately priced a bit higher than the 3.7 will be, from about $12-20K USD. Never heard or seen one myself.)

Anybody hear these at the recent RMAF show?

Like buttah huh? Wow, that's over $1K higher than I was expecting based on earlier grapevine. But hey, long as it's bright and metallic sounding with the proverbial great bass (and this with tubes no less!), surely we dedicated followers of Thiel will be in clover ;^)

Mcteague, did you buy finished or build your own, and how'd you hear them first? Reading the Linkwitz website, the Orion does seem to be in opposition to some central Thiel design precepts. Have you found it necessary to do anything special in the way of diffusing the rear radiation? I enjoyed the way Mr. Linkwitz was unabashed in discussing other speaker makers, and even providing links to them -- certainly a first from what I've seen -- although I noticed no mention of some (such as Nola and Genesis) who also produce open-baffle/dipolar, dynamic-driver designs.

PS - Think Cinematic Systems might approve of you now? Nah, probably not -- being as they're not in stores he couldn't sell these either ;^)

Hmm...I *do* listen to a lot of mono recordings, maybe I can get by with just one...

Has anybody else noticed that some photos of this speaker show what looks like a second passive radiator in place of the conical-diaphragmed bass driver with comparitively mild corrugations that we first saw? With no obvious attachment point for a voice-coil on the heavily corrugated but seemingly essentially flat, dustcap-less diaphragm, might these just have been stand-in appearances by the passive for photo ops while the real driver was out being worked on? Or could the final bass driver in fact employ, similar to the midrange ring, a non-conical, non-dome, corrugated flat diaphragm, outwardly identical to the passive? That would be radical, although I prefer the differentiated look with the grille removed.

Some interesting stuff there. As I speculated about in my previous post, the actual woofer does indeed sport a corrugated flat diaphragm, outwardly the same as the passive and different from earlier photos. The blurb talks about elimination of cavity resonances with this shape, probably more of an issue for a woofer in a first-order design. (I notice that Thiel has now adopted the term "wave-shaped" to describe the woofer and midrange diaphragms. Guess that's more poetic than "corrugated".)

Also learned that the curved cabinet isn't made from scored and bent MDF, but 15-layer molded hardwood ply, a first for Thiel I believe and more unusual. And the baffle is aluminum, like the dome-shaped top. No details yet on the interior construction, but the back seems angled-back similar to the front, although not the same angle. They're specifying 90dB anechoic sensitivity, but a 2.8 ohm minimum impedance, so beefy solid-state would still seem to be the preferred amplification. Anybody hear this at CES?

Boy is that reviewer a lousy writer. I assume the photos showing the differentiated woofer and passive radiator diaphragms are out of date, as his description of the woofer diaphragm seems to conform with the more recent Thiel website photos showing it looking just like the passive, that is to say not dished.

He seems not to have heard any current Thiel models for quite a while. As Unsound said, some of his caveats about past Thiel models' sound seem a little weird, to the extent that Thiels have typically offered an acceptably wide sweet spot due to their wide-dispersion design, and I've never heard the bass described as being slow on any Thiel. (Obviously it's not news to say many people have objected that Thiels can sound bright, which they can, for reasons we needn't go into again.)

Prior Thiels not using a coaxial M/T do have a narrow vertical sweet spot however (true of any multi-driver first-order array), and since larger Thiels have featured strong bass using low-impedance woofers, it's possible to result in an overdone bottom end response with the wrong room/speaker/amp combination. But it's true, as he found, that the 1.6 is a sweeter-sounding, less-demanding (and somewhat less critically revealing) Thiel.