Thiel Owners

Unsound - wave guides might have merit in the right designer's toolkit. But I am not that guy. The famous "lobing" is caused by vertical offset between the tweeter and midrange as a function of wavelength and crossover slope mating. The 3.5 drivers are very close, providing a pretty large vertical window for any seated listener more than 8' away. I consider that set of parameters as baked in to the fundamental product design. Wide horizontal energy dispersion is also quite good in the stock product; I'm keeping stock geometry.I'm working with surface treatment to absorb the energy propagating along the baffle surfaces.

I do not know Bau's or Dunlavy's later work, but your near triangle makes good sense. Before I left Thiel Audio, I experimented with tapered cabinets, which require CNC router-cutters with differing angles per each taper angle. In a production environment, quite a bit of complexity is added, plus no matter how sophisticated the cutter, the sharp veneered panel edge is somewhat damaged. We stuck with rectangular panels where the CNC-mounted saw could cut precise, sharp mitres.

We have identified a replacement midrange, with a new tweeter in the works - giving me the courage to address this classic model, which sold more than 5000 pair in a 5 year run from 1987 to 1992. That in many ways was a high-point of connection with our audience and market. At this point, I cannot address the equalizer. And today there are good subwoofers to augment the 3.5's extraordinary sealed bass.

Prof - thank you for your thorough comparisons and commentary.I have read Stereophile's reviews of the Joseph Perspectives and admire the outcome. I am a big fan of magnesium as  a driver material - the SEAS Graphene material seems great to me. Thiel products never got to that level of refinement with their associated costs. But in my fantasies, I would develop a tweeter with such a diaphragm to take the breakup above 40K Hz without electronic intervention. My experience with microphones says that magic would flow.

For the record, we can improve the 3.7 performance with passive component upgrades (like Beetlemania's 2.4s) and a little baffle treatment. Don't sell them yet.

tomthiel,
My post was also meant to justify my interest in whatever possible upgrades show up for the 2.7s.  It would be intriguing if a bit more of that "sonic purity" I hear in the Josephs could be introduced in to the 2.7s.(Even *some* movement in that direction would be intriguing).

Prof - there is some low-hanging fruit for the 2.7 upgrade. A 400uF electrolytic midrange series feed cap (although well bypassed) is certainly limiting the clarity-directness. Other XO tweaks too. The 2.7 baffle is nicely optimized, but I bet we'll gain some harmonic delicacy with treatment.

Yes, I’ve also wondered before about what might happen if the 2.7 baffle were further re-enforced. Though not being a speaker designer, I wouldn’t know the trade-offs. I’d imagine that if, say, you tried to re-enforce it from within, adding thickness with some material behind the baffle, you start intruding on inner cabinet volume, which could screw up some other parameters of the design?

BTW, I’ve now heard the much lauded Kii Three speakers twice, which use DSP to correct both for frequency response and time/phase coherence.

Maybe I still haven’t had a good demo of those speakers, but in neither set up did they sound as timbrally natural to my ears as my Thiels, nor did they image with the specificity and density of the Thiels.