1st Telecommuting Complaint

We have new neighbors. They are perfectly nice, I'm sure. (I still make it a point not to know the people I live near. Old habits die hard.) Today they are playing music in the room adjacent to mine. It's so loud the bass is rattling my windows. I tried knocking on their door and ringing their bell, but no one answered. So I left them a polite letter asking them to turn it down. I realize they probably won't get this letter until much later, but at least they know in the future to keep it down. I feel like an old curmudgeon, and I feel bad about leaving the letter. But if this is what I have to deal with from now on, I will have a rage blackout.