why do different road surfaces resonate differently through the car, with some being extremely quiet to others being very loud?

Most road noise has to do with the air your car is pushing out of the way underneath it’s tires. As your tires roll forward not all the air can get out of the way and it stacks up on itself creating an area of high pressure. When that area of high pressure is pushed into a crack or crevice in the road as well as your tires it has nowhere to go but out the sides or released from under the tires when it rolls off creating that “woosh” sound.

Newly paved roads are smooth with very little in the way of defects and cracks leaving very few places for the air to be trapped. This means the air is just pushed out of the way and produces less road noise. Though it will still produce some because of the air trapped in the tire tread.Older roads or roads with more porous material (for drainage usually) will trap more air and make more road noise.

Rougher roads also cause tiny vibrations in your tire and car creating just a little bit more noise, but not as much in comparison to the air interacting with your car and the road at high speeds. Also a bridge can make road noise louder since the ground isn’t there to absorb the vibrations in the road, that translates to more noise surrounding the bridge.

Vibration. If you roll a tube down you bench u can barely hear it. If you “roll” a square boxes down the bench it will go clunk, clunk, clunk.

So the rougher the road Surface is the louder it will be.

Answer: Tire thread and/or porosity of the road…

My Hot-rod’s tires are loud on concrete roads.

BUT… My Lawyer’s Lexis is quiet… Unfortunately, I paid for both ;-[