Thanks to those of you who have already done the experimentation. I have done some trials with my electronic crossover, and have settled on 160 Hz, along with a bit less gain on the low frequency side. There is now better bass definition, and better integration with the Fast 8. This all still falls in to the site stated definition of full range single driver, with 3 octaves to the powered subs and 7 octaves to the fast 8.