...I think where the O.P is coming from is setting off the sirens from the control panel, computer or what ever his county/city uses, under the supervision of who ever is in charge of doing so, present.
As far as what the experience would be like....depends ....
Here in Shawnee Co. Ks. if they where activated from either the 911 dispatch center or the Emergency Management office you would not hear them. If they where remotely activated via the lap top , then you could be standing right next to the siren.
I petition that everyone who joins the board should have to put there age or year of birth in thier signature...32 here
....54 for another year