Well, I now have ear wax remover fluid and ear plugs in, so I can't hear it anymore. Maybe he turned it off, maybe not.
I get along with this guy, and his family has been here since I moved here in mid-2000. I found and brought home one of their dogs one night, and we chat from time to time, but rarely. We just don't know each other that well. I think this is the first time that I've ever noticed him do this...I just hope it doesn't become a thing. I know that I listen to things fairly quietly, so me saying something is loud gets taken with a grain of salt - but this was loud. And really out of character, both for this guy and the neighborhood. We tend to be pretty considerate to each other.