Hey I installed a pair of polk 6x9's in the rear deck the other day. They were causing some serious vibrations back there, so as a temporary fix, I had some old dynamat laying around and decided to cut rings out of it and stick it to the rear deck to create a "barrier" between the speakers and the metal rear deck of the car. It sort of helped . My issue now is the bass resonance seems waaay off. The speakers don't sound nearly as warm as the factory ones I had in there before did. Any suggestions on how to fix this permanently? My current idea is to put some butyl rope on top of the dynamat and try and create a better seal there but not sure if it will make a difference. Any comments r welcome! Thanks!