STH-10, 2001, then SD-10

[kswx29]

STH-10 in Alert, 2001 in Attack and when they wind down you can hear a SD-10....this is most likely from the Springfield, MO area.
http://www.youtube.com/watch?v=82JGeGemEY4

[dboyle]

the SD-10s have a slight Penetrator or Allertor sound to them... especially during the wind-up. while they're running, the tone is off by just a hair.

[Thunderbolt 612]

That's because the SD-10, Allertor, and Penetrators used 9/12 rotors.

[Rheems1]

I believe the Penetrator, the Allertor and the Cyclone all have 8/12 rotors in them... so Dan would be right... it is a bit off from the SD-10.

Dave

[SirenMadness]

The Cyclone and the P50 definitely have eight-to-twelve rotors, though most Allertors have nine-to-twelve rotors; American Signal used to have their rotors built by Federal Signal, and I'm not sure as to whether they still do.

[holler]

It sounds like whoever is filming this was VERY close to that STH-10, you can hear almost hear it wind down completely.

[dboyle]

I think the Cyclones have 8/12 port rotors. I don't know for sure, next time I drive by one, I'll take a count. my closest TMI cyclone siren is a block and a half away.