Fire alarms from the 1980s and 1970s sounding like scoreboard buzzers.

I have commonly seen the sound of fore alarms from the 80s and 70s compared to scoreboard buzzers. People say those alarms sound like scoreboard buzzers.

I’ve seen people get confused by dryer buzzers in home economics rooms…

It goes back further than the 70s. Those kind of alarms were also common from the 40s to the 60s! I would imagine some people may get confused at my high school’s gymnasium; they have two Daktronics scoreboards from the 90s set up with Federal Vibratone 350s, and the fire alarm signals in said gymnasium consist of four Simplex 4040 horns and NO visual signals. I’ve often talked about how my high school’s fire alarm setup was VERY loud and VERY antiquated. Before starting college, I was mostly familiar with fire alarms sounding like said buzzers due to all my public schools having older systems like those in place (with my middle school being the oldest, using Federal Signal explosion-proof horns on a Gamewell fire alarm system from 1957!) Once I started college, I started to deal with the more modern electronic horn/strobes, and it was quite a difference (and I was kind of surprised to learn those electronic horn/strobes are nowhere as loud as those older buzzer-like electromechanical horns; not even the SpectrAlert Advance or TrueAlert can match or surpass the volume of an older Vibratone horn!) And speaking of my college, that confusion would definitely not happen nowadays; like my high school, the gymnasium in the Field House building is equipped with two Daktronics scoreboards made in the 90s with Vibratone 350 horns, but the fire alarm signals consist of four SpectrAlert Advance horn/strobes with protective cages over them (to avoid damage from basketballs and such.)

The alarms that sound like scoreboard and dryer buzzers are all AC-powered alarms. The reason they sound like that is because of AC current in the United States and Canada oscillates back and forth at a rate of 60 Hz. The horns will vibrate once each half-cycle, causing them to produce a 120 Hz buzz (roughly equivalent to a B note). You’ll hear a similar sound coming from certain appliances.

https://www.youtube.com/watch?v=2WFdyLAAzB0 - Electric arc at a US power station

https://www.youtube.com/watch?v=qynkLDvFb0E - Federal 30A fire alarm horn

In the UK, AC cycles at 50 Hz, giving you a 100 Hz buzz (~G note).

https://www.youtube.com/watch?v=ak6dQ8TfnDs&t=37s - Gent Tangent horn (rebranded Adaptahorn)

https://www.youtube.com/watch?v=Zj0j1HmKmZw&t=55s - Extreme buzzing on a UK transformer

I never really knew that Adaptahorns were sold in the UK after they were rebranded. That is interesting!

You know, it took me forever to figure out why AC buzzing sounded different in other parts of the world, then I finally figured out that 50 hz in the UK and 60 hz in the US sounded different. That’s why electricity produces a B flat note in America and a G note in the UK.

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