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.
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.