[old_tv_nut]

I don't know of any way a crossover could change the sensitivity unless it was wired entirely wrong and sending the wrong frequencies to the wrong drivers. Plus, in that case, it could only decrease sensitivity, not increase it. So, I'd think your speakers and crossovers are fine.

I don't know if the clipping before you get near max could be a clue, or not. But, what if there's a bad connection in the receiver where something should be loading down the signal more, or should be producing negative feedback to simultaneously reduce distortion and signal level?

Do you have other speakers to try and see if they are too loud also?