Thanks for the link. That was the one I found (1st), but I didn't see it at the bottom.You are correct about the crossover, but the manual gives the slope. The crossover is fixed at 100Hz and the slope is 12dB. My understanding is that you can bypass the built-in crossover.
Here is the manual and brochure for download:
Anyway, 100Hz, 12dB (LR, Butterworth?) isn't likely to be correct for the majority of HT sub installations, so it's not much of a feature.