Thiel Owners

FWIW:

Bass depth and weight are experienced as very similar between the 2.7 and 3.7. Though there are tracks where you can definitively hear the 3.7 go a bit lower.

The main difference is the sense of scale and linearity. The 3.7 just creates larger sonic images and a bigger soundstage. What exactly to attribute that to is a bit of a puzzle to me as they share the same mid/tweeter and only differ slightly in woofer size. Is it JUST that extra 2 inches in woofer size? Or is it something about the bigger cabinet of the 3.7 as well? I don’t know exactly what causes this difference.  Confusing the issue a bit further: with the brief tests I've done integrating a sub with the 2.7s, the soundstage does seem to grow somewhat, but I don't think the image sizes expand in to 3.7 territory - and yet with a subwoofer that's adding another 10" driver and producing more bass than the 3.7!

I’ve also wondered why the 3.7 sounds a bit more linear all the way to the bottom of it’s range. It could be a difference in voicing to some degree (maybe the 2.7 was voiced with a tiny bulge to compensate for it’s slightly smaller size - though I don’t think that was normally the Thiel way. Thiel was never shy about keeping linearity even if it meant their smaller speakers sounding a bit base-shy compared to some other brands).

I’ve wondered if the added control/linearity has anything to do with the different woofer constructions. The 3.7 has that sort of dimpled woofer and passive radiator and it’s general shape was claimed by Jim Thiel to get rid of some common reflections around woofers. So I wonder if that contributes.

@thieliste , How to differentiate the generation of cross-over of cs3.7? I got a black pair recently.

Any recommendations of add-on sub to match 3.7 or 7.2? My current equipments included Linn DS, YBA 1 pre-amp and accuphase m-1000 mono with MIT MH-750 shotgun speaker cables. Mark Levinson ml-2 mono are on the way and I will try them even they only have 25 watt per channel.

Happy Friday -All.

As alluded to above via driver size, air-coupling is a factor in the experience of bass authority. The 3.7 10" woofer has 50% greater area to drive its wave-front, reducing compressive non-linearities of air. Bigger makes cleaner. The 3.7 cabinet is also more inert and its baffle is less compressive for attack transient integrity. Regarding prof's thought about bass voicing, the 3.7 was Jim's work, the 2.7 incorporated various outside engineering input. Jim tuned his bass alignment to Q.707. Many designers give a little slop for "bloom, bigness, warmth", etc. I heard the two speakers at Thiel at finalization and heard the 2.7 bass as tuned a little looser. Most designers try to second-guess popularity, expectations and so forth. Jim was fairly immune to those ways.

Also note that image is highly dependent on cabinet and driver edge effects. Prof mentioned the driver part. The 3.7 cabinet design (love it or not) is very highly functional regarding diffraction, even though the 2.7 might qualify for world-class, it is not as good. 

A factor that contributes to "great bass" is that of articulation which, in a first-order design, includes the low end of the mid-range driver. Jim's 3.7 XO treatment is much more sophisticated and uses better parts than the 2.7 due to budget constraints and designer choices. The 2.7 midrange is fed through a 400uF electrolytic cap, albeit with a PP and styrene bypass in parallel. The 3.7 uses a bank of 75uF polypropylene caps with a styrene bypass. Multiple smaller PP caps provide faster reactions and less distortion than a large electrolytic.

Unsound, the 3.5 equalizer addresses only the bass with a simple, shaped boost centered at 22Hz or 40Hz depending on selection. Our reference set-up during development was bi-amped with identical amplifiers and 4 identical wire runs providing no EQ pollution into the midrange-tweeter circuit. (We were subsequently amazed by how many ways users could screw things up with varying amp and cable configurations working at cross purposes. So the bi-wiring option went away.) The EQ circuitry is elegant enough, but the budget required utilitarian execution (and use of generally inferior interconnects) adding some grain and haze to the signal. Jim considered the ported solution (O2, O4, CS2) to be inferior to sealed-box bass and only grudgingly accepted the market necessity of the passive radiator rather than the equalized bass in aspiring products. We aired the possibility of an EQ for the CS5 (the CS5 followed the equalized 3.5) and we talked about a follow-up super edition with an equalized bass. But Thiel was a one-man development lab experiencing high growth, and there was not time to explore such niceties.

One intriguing reincarnation for a CS5 Super would be to add balanced equalizers to the CS5 bass driving a separate bass input. That bass section has three  woofers in two configurations loaded by two sub-enclosures. All bass frequencies up to 500 or so are covered by that subsystem.