Our system is all 2001s as of right now. I believe the system exclusively warns of tornadoes, and during storm season they are silent tested. After a pretty horrible tornado destroyed a huge portion of this town, as well as killing many people who didn't take the warning seriously/were numb to sirens sounding because it was often a false alarm, measures have been taken to limit exposure to the sound so one doesn't build up an immunity.
I grew up in a small town in upstate NY! And all the sirens were omnidirectional and the bulk of them were fire station sirens. There are two that appear inactive and their purpose is unknown, but I suspect they were from the cold war era since that city was apparently a significant target at that time.
One of the fire sirens would sound for a noon whistle every day for many years!
And one creepy foggy day, an STL-10 sounded in attack and was audible from my house. I still don't know at all what it was warning for, but it was pretty awesome to hear. There's 2 STL-10s in the area, one of them being a fire siren and the other an apparently abandoned cold war, like I said. The cold war one is closer and likely more audible, which is interesting, meaning it is likely still in use? For what, I don't know!
Both of these towns are also college towns and both have sirens on campus to warn in case of dangerous incident like shooting events. One is a Modulator and the other is an ATI
sincerely yours, a weird siren obsessed deer