Modulator and annoying siren

[CTsirenhunter]

Well, it doesn't seem to have as many horns, but otherwise it seems similar. The first thing that I think when I see the siren in Corey's post is "dual-tone", in the sense that it seems to have four horns of one size and two of another. Of course, I don't mean dual-tone in the usual siren sense, and I'm sure I'm just plain wrong about that horn anyway...

[SirenMaster2000]

Wow, and I thought the sound of that thing was creepy! That first picture is creepier still! I don't want to see one of those in person *shudder*

[Matt]

Found picture of one of these:


and another video of the "Kockum KTG-9"

http://www.youtube.com/watch?v=tYqMpzNaxBw


So they're basically just a bunch of airhorns tuned to quasi-scale that sound alternatively?

this reminds me of my schools thor guard

[Daniel]

I think they use a rotating baffle-type valve system similar to musical automotive air horns. I suppose the point is to give a rising-falling sound between two set frequencies that imitates a siren but has the penetration of an air horn. That is the only siren sound I've heard that really gives me the creeps.