Why Aren't More Speaker Designers Building Augmented Widebanders?

Hi guys, I've been out of pocket for about a week, just saw this. 
@cellcbern  up front, I need to say that I've never heard your speaker... But, I have played with this 3 inch Tang Band and it is very good indeed. 
I agree completely with Erik about the 2K crossover point. In fact, might even argue that the 535 hz crossover quoted above could be harder to negotiate because it is clearly in the middle of the male and female vocals both.  In the end,  it is really up to the designer to be able to seamlessly integrate the drivers being used and as you have eluded to,  many cannot make that integration. 

Timlub- funny, I’m using the 3” TB W3-2141 for full range duties.  The 535 Hz crossover gave the flattest response without breaking the bank in caps and coils.  I can’t discern the crossover point when listening, and the speakers pretty much disappear.  But, it’s a challenge; I spent about 18 months with software, drivers, more filter designs than I can count and cabinet parameters before I got it right, to my ears at least.  

Here is a paragraph excerpted from Laurence Borden's July 2014 review of the earlier Bache 001 for Dagago. I think it gets to the heart of the augmented widebander advantage:


"In a typical 3-way speaker, the crossover point between the midrange and tweeter is typically between 1 and 2 kHz, which is smack-dab in the region to which our ear is most sensitive. No matter how well designed a crossover might be, the tweeter and midrange drivers invariably differ in their dispersion characteristics, transient response, and distortion characteristics. Making matters worse, the crossover often introduces phase shifts. Although these differences are often not recognized per se (except in especially poor implementations), they become apparent when they are absent, as they are in a speaker based on a wideband driver. As implemented in the Bache Audio speakers, the Tangband covers the range from about 100 Hz to about 10,000, or almost seven octaves. Not surprisingly, they are superbly coherent. As a result, music has a wholeness — or oneness, if you prefer — that makes it seem more lifelike. One has a sense of being more relaxed while listening, a trait I find very desirable in a speaker. Not surprisingly, instruments that span many octaves — like the piano — are especially well served, yet all instruments benefit".

Here's the link to the full review:

https://www.dagogo.com/bache-audio-001-loudspeaker-review

I don't remember it all perfectly, but I recall that the 3 inch or the 4 inch Tang Bands either one needed to be crossed around 200 on bottom and their  maximum usable frequency to keep within very tight tolerances was about 5k.... again on either 3 or 4 inch full range bamboo driver.  I guess that I could have played with other models, but at the time, there wasn't a lot of choices,  but from 200 to 5k, they were fabulous, easy enough to build a world class speaker. 

The W3 series, both ferrite and neodymium play out to 20 kHz.  The neo has a flatter frequency response, but they’re both very good drivers.  Going back to the OP, I think one of the challenges ( at least for commercial production) with crossing so low is that the crossovers end up costing more than the drivers.  Re-capping mine with Mundorf Supremes approaches $500.00.  But, I’ve built a few speakers with the typical 2nd order L/R at 2000-3000 Hz crossover- using pretty decent tweeters- and the wide banders come out on top.  I’m not sure why—they just sound more coherent.  And despite the fact that I’m using large values for caps and coils, the parts count is actually pretty low- not a lot of parts in the signal path- which might explain why they sound good.  Some of these designs use a simple first order x-over on the woofer and second order on the FR.  With impedance equalization you’re looking at maybe 5 components in the x-over, maybe less.  Compare that to the parts count in a 3-way.