Pete: Do you think that the purpose of the insulation material in the front reflex chamber is to help mitigate the chuffing from the inner ports? The frequency content seems about right. I wonder if anyone could have done a design like that in the days before CAD? If you are going to test a new blade, you'll want to do a better job avoiding the magnets than the Crutchfield guy. When he first started cutting there were a lot of sparks.