@mapman Wilson Audio's WATT/Puppy combo is a known example where the top two-way and the bass drivers are essentially separate speakers, but built to be a combination with matching crossover built in.
@avanti1960 Take a look at this chart:
Notice the increase in distortion at 200Hz and down (300Hz-700Hz range is what it is, no reasonable way to resolve that part) at these volume levels and up. By crossing over to a proper sub at 160Hz, I am offloading all of that from the LS50 Metas, and since the mid/low driver is the baffle for the tweeter (being a coaxial 2-way design), this also significantly cuts down on distortion for the higher frequencies as the tweeter's baffle is not experiencing very high excursion in order to produce deeper bass.
-Ed