Happened to be off of work today and found the courage to plan ahead well enough to be down in Rockwall for the semi-monthly siren test. This unit is 7 miles away from my new house, and you can hear it most days when the weather is good. There are several closer T-128's which do drown it out. My new town doesn't have any sirens yet, but I don't think it will be very long before we get them.
Rockwall has a mixed system of ACA/ASC products including the T-128, Allertonic 8000, P-15, and P-50. I believe there are only 2 P-50's in the system. There is at least one! They test the 1st and 3rd Wednesday of each month at 2:00PM, which is outside the typical 12:00 or 1:00PM standard for the Metroplex. I believe Eric Green recorded video of one of their electronic units.
I have a couple close up videos of P-50's and one of a Cyclone, so I thought it would be neat to get one from several blocks away. I used my Go Pro for the 3rd time since I've had it (2+ years) to see how it would handle the volume. It came out alright but there is no zoom. That weird vibratory/reverb echo is strong with this one, though the camera didn't pick it up as well as it really was in real life. I was approximately a quarter-mile away. Maybe a little less. This siren is next to a Sonic on Goliad, South of downtown Rockwall.
https://www.youtube.com/watch?v=93dpoE0Hfy4