Well, I have a small sub in my car that sound great inside, but can't even be heard outside. How about the fact that the owners of those big, loud kickers also have their windows down. This must make it sound better. Also, have you ever noticed that a car behind you sounds louder and gets quieter as it passes you, even if it's stopped. Something about the sound propagation. And if it takes 28 feet for the sound to "develop", why can I here that 22Hz note in my 19x15 livingroom so well? Can barely hear it outside the house.
Annoying sounds from cars at stop light
What causes the stereo in the car next to you at the stop light so loud and annoying with over the top bass and how can the driver stand it?