Whelen 2910+VisuAlert & Modulator 4016 siren test, North Chicago, IL 

0:04 - Test message
0:55 - Alert (Lake Bluff's 2001-130s heard prior)
4:23 - Test message (Lake Forest's 4004s heard in the background)
5:22 - Naval base Modulators start up in wail
6:24 - University Modulator voice & alert
These two sirens are located at Rosalind Franklin University on Green Bay Road. The 2910 is owned by North Chicago and the Modulator is owned by the university. The 2910 is a mere 220 ft from the Modulator, but was installed after the Modulator when North Chicago got their new system in 2011. The Modulator has been up since around 2008. The VA hospital nearby owns a 2806 and 2802 that are tied into North Chicago's system which you may be able to hear at points in the background. The other Modulators heard in the background doing wail are owned by the nearby naval base.