TTI exhaust too loud

I have 2 small block Challengers, Both with 2.5" TTI exhaust and Dynomax mufflers. One with the "H" pipe has the drone you are talking about around 2000 rpm. The "X" pipe system while a little quieter out the back at idle, has NONE of this drone. I guess something about the "X" eliminates it. I have also eliminated it on past cars with the round glasspacks installed next to the fuel tank.