Best loudspeaker with coincident/coaxial driver

One more idea to consider. Coaxial drivers or single drivers are one way to skin this cat. However, certain multi-driver speakers have either no electrical x-over network or a minimalist x-over. To my ear, this may be more critical to coherence than driver placement. One such design, from Reference 3a, uses no x-over on the midrange driver. This deCapo monitor only employs a really minimal network to protect the tweeter.

A slightly different example is the Gallo Strada reference. It has limited deep bass due to the lack of a true woofer. However, its twin mid-bass drivers are run full range and are augmented by a very robust tweeter with no electrical x-over network at all.

The other thing to consider is x-over frequency. Adding a subwoofer to the Strada (necessary IMO) adds a crossover, but it's below 100hz where IME it's less likely to disturb a sense of "coherence" (provided that it's an appropriate sub and integrated to the mains properly). Similarly, some of the older, large Ohm designs use a main driver that is run "almost full-range", crossing to a tweeter at 10khz, again well out of the high sensitivity zone.

just food for thought.

"09-30-15: Mapman
The only thing alone that has a good chance of assuring anything is a large number of very happy users."

That's exactly what my aunt says when she takes these little blue pills she's always popping. Her dog likes them too.

The OHM CLS Walsh driver might be considered coincident but its not coaxial. The Wide range Walsh driver used is what makes it special. Crossover is at high frequency and very simple as well. Most coherent sounding! Hence the name CLS (Coherent Line Source) driver. Also highly omnidirectional.

The only thing short of the "holy grail" is its not full range single driver20-20Khz but a functional close approximation if you look at the frequencies where most music we hear occurs. That and maybe the taget audience is the masses of music lovers not audiophiles so cost is a factor in the design.

ZD,

Well, there you go....

I can understand why the OP chose the subject line that he did, as his 14 X 13 room is a bit on the small side (with other potential issues as well). If the speakers need space from rear and side walls, driver integration might become an issue; and ergo coherence as well.
I would recommend Thiels, but the 3.7's might be a bit much for such a small room, perhaps some of Thiel's other smaller offerings might be a more appropriate fit.