I helped this other guy in another Forum that needed x-overs for his Founteks and 'modeled it with one second order LF/HF x-over that worked pretty well. The guys in the Forum were amazed because they had plenty of notchs and 4.order LF x-overs that we needed because the 6" midd-bass was peaking at 5/6KHz next to x-over frequency. The result was that going down in the x-over freq. to 2kHz helped, what gave it a beautiful curve down in the problematic area of the peaks in the 5K range. So, the guys were amazed because the second order x-over was giving them a third order slope and that was what everybody was looking after.
I think you 'stated' in your White Papers that it is the voice coil (inductance) 'working'.
Best Regards