My system has low sensitivity (89 dB) speakers all around, so to lower the load, I started crossing over my speakers at 80 Hz to lower the load on my somewhat challenged amp, even though all would indeed run full range. For my system (two subs) and tastes, this was a good solution. I achieved a higher SPL, with a minor bump in the frequency response. I would only suggest this if you have an overtaxed amp and low efficiency speakers, as that is my case. If I had more power to play with, I would attempt to run my speakers full range. Personal taste is always a factor, though.

S.