http://www.youtube.com/watch?v=R7ixJRPmjxA
Missed the wind up as I didn't know when the scheduled test days were. If today is any indication, than their testing is every second Friday of the month at 1PM. They test for 3 minutes and only use the Alert signal.
Recorded from my drive-way.
Pictures of the Siloam Springs, Arkansas sirens can be found at my DA page:
http://coyoteunknown.deviantart.com