Crossover-less Speakers

I did but have not heard any single driver that I could unconditionally recommend. All are idiosyncratic and you have to accept each's limitation, just like any speaker.

I am now leaning to 2 way / no x-over like Epos, Andra I, etc. or Shadorne's suggestion of active.

My dream would be Audio Technologies Flex driver run full range and hi-pass a tweeter over 6kHz. Note that these drivers are in the $20,000 Peak speakers.

Tbj, let us know how like like the Feastrex thanks.

"Different parts of the cone respond at different frequency,"
Assuming the cone is not behaving like a piston. But you don't know that. Even multi-way speakers, 1st order x-over included, can exhibit this. If you cannot hear the improvements in dimensionality and PRAT with a time and phase coherent speaker then stay with multi-way.
Perhaps this is one reason people like tubes. Put some dimensionality back in what the non-time and phase coherent speakers take out.
Further, Tannoy has a white paper on this, when you have 2 or more non-coincident drivers dispersion is compromised. In some areas the drivers cancel each other out. Read any of JA's analysis of speakers and you will see you have to listen below the tweeter's axis or a large suckout develops. A single driver or coincident drivers like Tannoy give the most even dispersion patterns.