Notes:

This is based off how System Sensor's SpectrAlert Advance series of fire alarm signals are one of THE most common fire alarms used throughout the USA. It's gotten to the point where they've even replaced the first fire alarms I've ever heard in my life, at my first elementary school (they were Simplex 4051+4050-80 horn/lights; they got replaced when the original Simplex system from 1974 started failing and had to be replaced, going with a Notifier system), and they're also common at my college campus (again, Notifier systems, in some cases even replacing those same old Simplex alarms my elementary school had!)
And yes, SpectrAlert Advances are one of the loudest electronic horn/strobes out there (alongside the Wheelock AS and the Simplex TrueAlert), but they can't beat those old electromechanical horns and vibrating bells in terms of loudness!
They were mostly discontinued recently in favor of System Sensor's new L-series alarm signals that sport a more streamlined design, and sound similar to the Advance but somewhat less harsh-sounding; those will probably soon become just as common within five years!