No person shall operate or use... any personal audio device in such a manner as to create an unreasonable noise.
Cool, so can we put half the city in jail? Because one of the most annoying things people (and I mean lots of people) do on the subway is crank their iPods way up so we can all hear the batteringly repetitious beat of whatever house song they chose to start the day with. Surely all reasonable people agree such noise is "unreasonable"? But perhaps the law should be more specific:
Unreasonable noise shall include but shall not be limited to... the operation or use of such a personal audio device on or in any public right-of-way [public place] so that sound emanating from such a device is plainly audible to another individual at a distance of 25 feet or more from the source.
I imagine this law was written to provide a legal basis for harassing kids with ghetto blasters and old men with their folding chairs and sports radios. Indeed, the definitions of a "personal audio device" are cute: "including but not limited to a personal radio, phonograph, television receiver, tape recorder or compact disc player." I don't know what any of those things are, but they sound a lot like antique versions of today's mp3 players and music-streaming devices.
Twenty-five feet sounds like a sizable distance, but most NYC subway cars are between 50 and 75 feet long, which means if you're standing exactly in the middle of a 2 train and you can hear the music coming from anyone's headphones, that person is breaking the law. Immediately notify a police officer, who will surely be familiar with the section of municipal law to which you're referring.