Why would you say I "hate Americans"?

You live in a country that has a lot of issues and crime, yes, but as I always keep hearing in gun debates, "it's not most of the country". So are you really saying America is in such a state that trying to talk to a neighbour is too dangerous for anyone? That's horrible. I would help if I could. Which is for instance why I very often argue for reasonable gun control which would help with your situation.

And again, doesn't change that an anonymous letter informing someone that their morning music seems loud will work better than disconnecting a speaker.

The latter will only confuse the person who will fix the speaker connection or get a new one.

Dude, as an American it just sounds like you have an anti-everyone else hate and fear boner because you're antisocial, scared, and paranoid. The other dude is absolutely right that there are more civil and diplomatic ways that will be much more effective than not. At my girlfriend's last apartment there was a dude who lived below her her apartment who would occasionally play music really really loud. I had seen him openly carrying his pistol in the building. I went down there and knocked, and when he opened the door his gun was hip holstered and ready to be drawn. I just asked if he could turn down the music a bit as we were trying to sleep and he apologized and all was good. He turned down the music and there was no confrontation; he may like his music loud (as do I sometimes, my hearing can be bad at times) but sometimes we need a reminder to be considerate of others. You can argue we shouldn't need that reminder, but we're all human and to be human is to be fallible. At the end of the day, communication will always be the quickest way to solve a conflict or issue. It is only not an option when one or more sides refuses to cooperate in communication. But that's honestly not as common as you'd think and it doesn't help you nor anyone else if you immediately close that avenue of resolution.