Sub is Reverberating/Rumbling

[igotcabada]

Having an issue with my sub (polk psw10) in certain parts of movies.

There seems to be a sort of vibration/rumbling coming from the port (i think) occasionally. I have it about 40% up on the back of the sub, the hz crossover dialed up all the way on the back of the sub, and the crossover set at 80hz on the receiver.

I have 2 subs hooked up, and it happens to both of them at the same time.

For an example, the exact opening scene of transformers with the osprey's flying it was happening. I played this scene over about 20 times with different levels, and couldn't get it to go away. when I dialed down the subs to about 20%, I could still hear it.lhttp://www.avsforum.com/avs-vb/showt...9#post13782559

I tried searching & reading the stickies, but most of that was in Greek to me

Anyone experience this? Is there a fix? Can my sub just not handle certain bass levels?