Bob Brines made a statement of fact. He said, "Single-driver full-range speakers have a limited dynamic range." This is true of all speakers, but I think what he meant is that single driver speakers are limited more because of their unique characteristics. It wasn't about a particular implementation, it was about any speaker with a single driver.

By the way, what was used to come up with those SPL figures you quoted? There is a lot of specific information in your post, so I'm sure you must have this information handy. Point source sound falls off at the rate of 20 log d1/d2, so you can see that 108dB at 14 feet is about 120dB/M - pretty strong stuff. Those are prosound levels, amazing from a 4 inch full range speaker.