Re-ran Audyssey a few weeks ago and loved the results after following scrupulously all the instructions for mic-placement, etc. here. I had added some bass traps and broadband absorption across my front wall, so I thought I'd re-run Audyssey.
Wow, the result was wonderful across the board until I hit scenes with ultra-low hz material. Those scenes are way too hot now for my Ultra.
For example, in Transformers where the choppers fly in at the start--now I'm getting room-rattling extension and power like I never have before. Also, Spiderman 3 with the spinning sand pit machine is just unbelievable. However, in both those movies where other scenes have lower hz stuff, the Ultra makes bad noises--it is clearly being over worked and it make those frightening (in a bad way) mechanical noises.
Honestly I like the overall effect on everything else except the sub 20hz scenes. BTW, I'm running my Ultra in 15hz mode, no room-compensation, in a 2,700 sq ft room (15' x 27' x 7.8'). My processor is the Onkyo 875 being used as a pre/pro.
The only thing I can figure is that there is some over-cooked boosting going on down in those lowest frequencies.
Earlier today another Ultra owner (with duals) reported having the same experience in another thread! I'm kind of relieved because I was worried I just needed to get another Ultra to compensate for the infrasonics.
I actually posted some weeks ago about the "hotness" of Transporter 3, but it turns out that everything I play which has very low hz material just overwhelms the sub.