Dear Lew, I certainly understand your interest in speakers.
To understand this amazement about Ribbon speakers in
combination with ''ordinary'' kind one need to investigate
the work of Prof. Jurgen Scheuring designer of Ascendo
series of speakers with his Ascendo M-S as the top of
this series. There was a review in Absolut sound but I can't
remember when. Anyway it was an ravishing review. As far as
I remember the ''unusual'' construction consisted of ''band pass''
woofer ( Eton 11'' driver) 8'' Danish mid-driver and long ribbon.
The ribbon was time-aligned with an metal construction allowing
fort and back movement of the ribbon. One was assumed to
measure the distance to the sit position and adjust the ribbon
accordingly. Alas the price was such that I could not afford it.
The obvious difference with Syntax sample is that the later
ribbon can't be moved fort and back. I am sure you will be
very interested in Prof. Scheuring arguments and cross-over.