Thiel Owners

unsound - points well taken. Thanks for your linked reminders. And a comment here. My thought was more from the perspective of the extreme difficulty of producing so much bass with the dynamic range and extension possible with today's digital techniques without running out of steam somewhere, especially at the lower reaches of the midrange driver. My hypothetical suggestion would include placing the stereo subwoofer pair to create proper time arrival with the main speakers. The main speakers would be relieved of their heavy chore of reaching all the way to 20 (or 40) Hertz.
All that said, I really love the 3.5s I recently got via this thread, and do consider them, like others here, to be Jim's quintessential work in many ways. I also apply that to the (unsuccessful) CS5 short series. Of note is that those speakers are truly minimum phase transducers, all the way to the deepest bass - and the sound underscores it.

More later. A guest just arrived.

A Renaissance 3.5 would require all new drivers. The extant woofers are bulletproof and decent, but lack the sophistication of later designs. They are a 1985 solution. The replacement midrange needs to be a full range driver, which is findable, we just haven't yet succeeded - same with the tweeter. The XO upgrades I have been developing this past year all apply to the 3.5 to up the performance league dramatically.
The EQ could also be executed better. It is all discrete, and therefore upgradable, but it is likely that a talented circuit designer could do the job better today. Now, IF the EQ could be a requirement rather than an option, then other possibilities emerge. The midrange / tweeter could run on one channel with no boost to its low end. The equalized woofer would run on the other channel for good power balance. The crossovers could be incorporated into the EQ before the power amplification stage. It is possible that the woofer, or all the drivers could run crossoverless for direct, lossless feed, or with driver-specific and tweakable elements installed in an outboard XO near the cabinet. Such an active-crossover analog solution would squarely fit Jim's approach and sensibilities, and indeed one of the original design pilots which was deemed unfeasible in the company's fledgling state.

As an aside from history, I really like the 3.5 cabinet which shares technologies with the CS2 and 3 but obsoleted by the 2.2 and onward. Those early cabinets used MDF only for the baffle for its sculptability. The walls are 1-1/8" industrial particle board laminated both sides - for about 1.5x the stiffness of later 1" MDF cabinets. For production management reasons we landed on 1" MDF as our sole cabinet material. But the particle board is better.

Obviously, I am personally more excited by this potential upgrade than by pairing the non-eq 3.5 with a sub. But it would take lots of doing by someone(s) with youthful talent and vigor to pull it off. BTW: the CS3 cabinet is functionally identical to the 3.5; the combined 3 and 3.5 models sold about 7000 pair, and the 03, 03a adds another 2000 pair build of 20mm FinPly (better than BalticBirch or ParticleBoard). Hmmm.

Excellent discussion and an exchange of ideas moving the 3.5 into 2020 and beyond.  The addition of subwoofer(s) seems a logical progression given that critical parts for the older EQ might not be readily available.I can remember  1985, a long time ago, indeed.
Happy Listening!

tomthiel
Keep up the outstanding Renaissance Thiel work.
Happy Listening!

@tomthiel, as usual an excellent response.

I do think that 40 Hz is not too much to ask of a 10" woofer.
Of course, as has been discussed before these suggestions could double one’s amplifier budget. And, with 1st order crossovers there would be quite a bit of overlap, suggesting that even more so than with other configurations, using identical amps would be preferable. It might be more palatable if there was an upgrade path from 2 channels to 4. Or more?
It’s quite a testament to all at Thiel Audio that a 30+year old speaker is still so relevant today!

Other than the huge amplifier requirements and depending on perhaps too complicated a crossover when a more thought out baffle arrangement might have sufficed, I don’t consider the CS5’s to be unsuccessful. When properly powered, in the right room, they are still amongst the best I’ve heard. Perhaps you mean from a marketing perspective?

Could your suggestions applied to an updated 3.7 with a sealed box and woofer drivers from the smart subs might be a consideration? As I understand it, as is common with so many integral self powered subs with Class D amps, the amps are often problematic. Would the sub drivers have huge power requirements? Too much to be practical with Class AB amps?

@jafant , I don’t believe eq parts would be a concern.