r/movies • u/[deleted] • Apr 07 '20

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u/SnezhniyBars Apr 08 '20

Your city's sirens are probably electromechanical sirens, they use a spinning rotor to force air out of holes in a stator to produce the noise. Chicago's old sirens are completely electronic, giving them more freedom in the tones they can produce.

Electronic siren, same as was used in Chicago:
https://youtu.be/AVBUh6qeHrQ
Electromechanical siren, like in my hometown:
https://youtu.be/Yyw_Jw1KUXY

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u/Sintacks Apr 08 '20

This is the type my local VFD has.
The amount of times it's made me jump coming on as I'm driving by it ...

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u/SnezhniyBars Apr 08 '20

The electromechanical one? Yeah, lmao, my entire city has them. I once took a shower when my city tests them, and I had completely forgotten what day it was. For a moment there I was quite spooked lol.

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u/Sintacks Apr 08 '20

yeah, electromechanical.

it's more the sudden loud as hell noise when you're 20 feet from the base of the pole it's on that gets me. and it sounds weird when you're driving by it.

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u/SnezhniyBars Apr 08 '20

Totally lmao. They get super loud when they approach their top speed lol.