How can you tell if someone can hear your car stereo more then 75 feet away from ur car? The state of Arizona has done studies that say you cant. Each person hears sound in differant ways. Just because I can hear it 75 feet away doesnt mean you can hear it 75 feet away. The only way to make this ordinance right is to get a devise that can measure sound. I dont think the City of Decatur has one, and if they do they are not using it. Every police officer should carry one if they want to keep th...