This. In many cars, especially the ones with full tailpipes, the drone isn't from noise out the tails - it's noise resonating through the body of the muffler, then into the floor pan of the car. Since we tend to try to fit the largest mufflers under the car, and install them as close to the floor as possible, this tends to increase the possibility of an exhaust drone. To over-simplify - sound doesn't pass "through" the muffler body, the noise inside is sound pressure waves that flex the metal body, resulting in sound pressure waves that are created outside the muffler body, and are then transmitted to the floor pans, causing a drone. And yes, sometimes changing or adding mufflers can remove the drone, by changing the sound pressure waves in the system. But I've had better luck removing drone by insulating the body of the muffler than by changing them, or adding a resonator. I usually do a layer of header wrap covering the muffler body sides, a layer of 22 ga stainless sheet, and repeat for a total of 2 layers of each, holding them on with the metal header wrap straps. I've also used old welding fire blankets and hi-temp fiberglass sheet for the sound deadener.

I can't guarantee this will fix every instance of exhaust drone - I'm just offering another method of eliminating it to consider that has worked well for me in the past.