A lot, if not most people, buy their music for THEM to hear, not others outside the vehicle.
Every system I've had, people have always told me that they could hear me coming from a long way away. Thats not what I wanted, it just happened like that.
Some of my friends have ported setups that are tuned too high, and for some reason I can't hear theirs until they pull up. But my friends with sealed setups, and reasonably tuned ported boxes can be heard from pretty far away. My guess is, it's the lows that they hear. The lower the bass note is, the longer the wave is. So it probably carries further.
My friend has 2 12" L7s tuned to about 38hz. I can hear him from about a block away when his windows are down. When I had my setup with my box tuned to about 35hz, people told me when I pulled up, that they could hear me turning corners a couple of streets over, and that they could tell about how far away I was by how loud it got. I only turned up like that when I was trying to shut my friends up from bragging about their crappy systems. I never listened to it that loud for normal listening. Plus when I had it up that loud I had earplugz in //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif
Right now your in a stage that I hope you grow out of fast enough to keep most of your hearing. People that think like you do concerning car audio usually don't give a care that the music is hurting their ears, they just want to get attention when they pull up. And believe me, if you want attention, you'll definately get it when you get about 35 and wear hearing aids //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif
Snap out of it.