I happened to have some time in my schedule to get in a first Wednesday test. There were some other sirens in the ATL area that I wanted to record, but I opted to record this par since the systems test at the same time. They sound pretty interesting running in alert together. This is my second video of an I-Force, and honestly it isn't half bad. It's pretty much on par with a 2904.
For those not familiar with the area Cobb County's system consists of various Whelen Vortex R4's, WPS-2810's which supplemented and eventually replaced a system of older Federal sirens: Thunderbolts, SD-10's, at least one RSH-10, an assumed Loudoun ES-1000 (people call it a Whelen, but it sounds nothing like a WS-1000), Sterling M-10, etc. KSU's system consists of these early model I-Force STi-1600's, an I-Force 2400 and E-Class EC2, and a setup of Ultra HyperSpike speakers and a 2904 at the Marietta campus that replaced a STH-10 and pulls double duty as a county siren. Dobbins AFB has a system of E-Class EC8's and I believe an EC4 that replaced a system of Loudoun ES-2000's and at least one Loudoun, possible ES-1000 with round horns, set up as a bidirectional siren, which apparently replaced a system of Model 2's. Lockheed apparently maintains a system separate from Dobbins consisting of a couple of 2910's, one replacing a 2001-SRN, and a 2904. Smyrna also has a system of Vortex R4's that replaced STH-10's, Thunderbolts, and another assumed Loudoun ES-1000.
Cobb County and KSU test on the first Wednesday of the moth at noon. Dobbins's and Smyrna's systems are augmented with Motorola ACE3600's like the county's system, so it's possible that they are tied into the system and test at the same time. Lockheed's Whelen's appear to be operated by the plant and don't use the RTU's, so it's up in the air as to when this system is tested.
https://www.youtube.com/watch?v=m7NHZbVKQms