I know this video is rather late, but I didn't have my camera on me for over a week after this test, and when I finally got it again I had to motivate myself to upload this video.
Anyway, this T-128 is located next to the water tower on Connemara Trail in Rosemount, and indirectly replaced a Thunderbeam several years ago. This siren was retrofitted with Federal Signal CommanderOne not long ago, and now has FS controls. It ended up being louder than I expected, and you can hear several other sirens in the area after it winds down.
Sirens in Dakota County, like most of Minnesota, are tested on the first Wednesday of each month at 1PM.