I didn't go out to record anything up close, but I do have this recording from my grandpa's back porch. They tested the sirens in the usual 3 minutes of Alert, but about 40 seconds after the main test, they sounded them in Attack for about a minute for some reason. This is a system recording featuring 3 Thunderbolts, and some other sirens in the background. I was hoping for better siren ambiance, but the wind direction prevented that.