I have the Magnepan MG-3.6/R, with a freq resp of 34hz-40khz. Since they are dipole planar, which loads the room very differently than enclosure based woofers. That is why I am going as low as possible on the crossover freq in order to preserve the sound of the maggie bass.
I don't use the Meridian's crossover because it follows THX's crossover scheme of 2nd order HP and 4th order LP. The crossover in Hsu's amp is 4th order HP and LP.