https://m.youtube.com/watch?v=kRCdnqgGoTc
https://m.youtube.com/watch?v=GzdlAw82DYc
https://m.youtube.com/watch?v=XQJ1UrYovVQ
Up until about 5-10 years ago, it peaked at the normal speed. And then, it was suddenly very muted sounding, and you couldn't hear it inside the house across the street. And then, they took the siren down and apparently fixed it, resulting in the way it now sounds. It is still very loud, but not quite as loud as it was originally. The neighbor, who doesn't know anything about sirens, thought the siren broke and they got a new one that wasn't quite as loud, but still did the job well. I know it's the same siren. It's not single phase-3 phase with a rotary phase converter. Maybe something went wrong and they fixed it, but accidentally wired it backwards?