Vandersteen Model 2D?

non pistonic is out of phase behavior...they are same thing

I don't find the sound of a driver at break up mode the same as a speaker with a high-order filter, if that's what you're meaning. One is distortion and the other is a very subtle sonic signature. I would much rather have something like a Vivid B1 (pistonic but with out-of-phase filtering) than a Vandersteen 3 (phase coherent but not as resolved because of the non-pistonic diaphragms). You can "have it all" with the Vandersteen 7 but that product is just a bit out of my budget :)

Beetle....maybe....but perhaps we might compare speakers a bit closer to price parity 3:1
is a stretch even for the frugal Dutchman to overcome...

but yes, i would say the KEF and B& W alumni who believed in FFT and laser inferometry of drivers would have a bent for that..

the steep slopes make it easier to get pistonic behavior in the passband....

i am spoiled, admit it.....

search utube and you can find some cool video of Vandersteen 7 drivers and another brand X undergoing the lastest laser measuring technique...out of phase in RED, sometimes 10% of output... 

and yes I was being dramatic, I think understanding the trade ratio of pistonic vs phase and time accuracy might be interesting, especially as measured vs what we actually hear...

speakers a bit closer to price parity

Fair enough. My non-parity example reflects the dearth of both phase coherent designs and designs with pistonic behavior. Both of these groups are very small and the overlap seems to stop at the Vandersteen 7 (maybe 5 Carbon and out-of-production Thiel CS3.7)! But I stand by my point if we compare the Vandy Quatro CT and Vivid B1, which are at the same-ish price point.

the steep slopes make it easier to get pistonic behavior in the passband....

Yes, that’s what I implied earlier ("especially important with XOs using slow roll-off filters "). Even with steep filters you need a well-behaving driver.

I have lived with Thiels or Vandersteens for over 15 years. So, I am very familiar with phase coherent sound. But during that time I’ve listened to many other speakers. My favorites, alphabetically, are Avalon Ascent, TAD Ref 1, Vandersteen 7, and Vivid Giya. Only the 7 is phase coherent, although the Ref 1 has a coincident midrange/tweeter. But one thing these designs have in common is pistonic behavior. IME, that one factor best corresponds to high resolution and transparency.

yes i thought we were essentially on same page and if we use the 5a carbon it flips 2:1 ish the other way, also not fair...

not many choices IF one values both....

i am excited about some emerging technology in both materials and process that might get the rather significant cost savings needed to compete with woven prepregs, etc...

i think if we look at the real costs ( capital opportunity ) machined aluminum is pretty expensive
wish Jim T were here tho.....

i think at these  levels of performance ignoring the cabinet is perilous also...

not to beat a dead horse but it is freaking amazing the value in a pair of 7’s
just try to find a used pair....candy everybody wants to quote a band I enjoy