exhaust drone/harmonic resonance

I have hedman short tubes into 2 1/2 wth dynomax super turbos no h pipe , out the back through stock tips , no drone at all . Am able to listen to the radio at highway speeds , from 1900 up to 3,000 . Have 3:23 gears and automatic , no sound deadner , just what came from the factory .
Bought the car it had cherry bombs on it , no drone , just loud !!
So many variables , hard to track down with all the combinations , motor , gears , tires and transmission.
Good luck getting rid of the drone .