Wed Feb 03, 2016 7:08 pm
Since I've lived about two blocks from an STH-10 (it was installed in the Spring after I was born), I'm pretty familiar with how loud they are. I can assure you they are nowhere near 125dB at 100'. That's like comparing it to a Cyclone. They are, however, slightly louder than 2T22/3T22s, mainly because they have a much larger rotor. 2T22s are mostly projectors, volume wise.
As far as hearing one 6 miles away, there are a number of things to consider like ambient noise levels, wind direction, objects between you and the siren, etc. Yeah, maybe you can hear one that far away in calm and clear conditions, but it definitely would not be loud enough to be heard during a storm, which is when it actually counts. I personally find claims of sirens being heard at great distances a bit irrational, but if it makes you feel better, then have at it.
Federal Signal Model 2-240, Thunderbolt 1000AT, 3T22A
Federal Sign and Signal Model A
Federal Electric Type B
Sterling M Single Head