The Siren Board

Since the invention of the air raid siren, there has been a few models with square horns.
Here are all the square horn siren models I have heard of:
thunderbolt, STL-10, sentry 20V2T, ACA hurricane MKl, and SoCal Edison model 120.


If I missed a siren, please let me know.

There are a few examples of square horned ATI's. One example I know of is the one at the University of Alabama.

OK. Here are some sirens with horns modified into square:

Whelen vortex and Alertronics too.

Oh. I guess I was not thinking electronic

federal signal 3t22 wrote: ↑

Tue May 06, 2025 7:30 pm

OK. Here are some sirens with horns modified into square:
download (15).jpeg
download (16).jpeg

The ATI's are factory, not modified.

UOO Jyri siren. Rather obscure and one of my favorites! I’m a fan of sirens with square shaped projectors.

PS : the images will not load unless you click them and click "open in new tab" then they will download.

some french sirens came with square horns, albeit insanely rare, here are a few square horned units (please note these are not my pics) :

square horn CICCA, only one know, might be a hackjob


square horn CEN, one of a few known to exist, most likely not a hackjob


square horn PTR, definitely a hackjob


square horn CEN (2), most likely a hackjob


square horn CEN (3), 10 ports, definitely a hackjob


square horn CEN (4), most likely a hackjob (siren has been moved to a unknown location since picture was taken)


square horn unknown siren, no information available

In london ohio, we used to have a custom square horned Federal Signal 500 AT, it was CUSTOM, but the horn broke so the horn got replaced by a round one around ~2 years after the unit was installed because the city didnt feel like making another square horn

Kaleidoscope wrote: ↑

Wed May 07, 2025 1:01 pm

In london ohio, we used to have a custom square horned Federal Signal 500 AT, it was CUSTOM, but the horn broke so the horn got replaced by a round one around ~2 years after the unit was installed because the city didnt feel like making another square horn

Is there any reason why they went with square horn, and also are there any photos? I am interested now