I'm not going to look it up for your state, but in CA if the music is heard more than 50' from the operating vehicle, then it is in violation of the Vehicle Code. I suspect that is the same in PA as well. I doubt it requires decibels so much as it requires distance.
One does not have to possess aftermarket speakers to be playing their music too loud.its absurd you could even be pulled over and still given a ticket when they can very clearly see there is no aftermarket stereo in the car.
- Carl

