The red means it is exceeding xmax. Reduce the power in max spl until the problem in the middle goes away. Most of the time the max spl sim shows over excursion below cutoff so that is where I set my HPF, but the middle parts I try to eliminate. That will reduce the SPL of course. My Faital Pros in 1850s start having over excursion over 300 watts even though the speakers are rated for 1000 watts RMS.