Dec [{()}]1d ago

Skoda developed (with the University of Salford) an all-mechanical bicycle bell that bypasses active noise cancellation (ANC) in headphones.
https://www.skoda-storyboard.com/en/skoda-world/skoda-duobell-a-bicycle-bell-that-outsmarts-even-smart-headphones/
It's tuned to 750hz, which is a "blind spot" in most ANC headphone processing.
There is also a resonator for a higher frequency, and the hammer produces irregular strikes, confusing the ANC further, and making pedestrians look behind them faster.

Video:
https://www.youtube.com/watch?v=zDaVPfpQvPI

Research:
https://cdn.skoda-storyboard.com/2026/04/Skoda-DuoBell-Research-final_cf127752.pdf

#BikeTooter

Škoda DuoBell: A bicycle bell that outsmarts even smart headphones - Škoda Storyboard

Pedestrians wearing headphones are exposed to an increased risk of accidents. In an effort to reduce collisions with cyclists, Škoda Auto, in collaboration with scientists, introduces an innovative bicycle bell whose sound can penetrate even active noise cancellation systems. In doing so, it helps prevent injuries to both pedestrians and cyclists.

Škoda Storyboard
Show threadMoz1d ago

@dec23k that is very cool. But I can't buy one!! Hopefully people start manufacturing them because the noise cancelling problem exists in Sydney, Australia as well.

#SkodaDuoBell #DuoBell #BikeTooter

Show threadDec [{()}]1d ago

@moz
It should be possible to build a simple battery-powered electronic 'horn' that pulses a tone around 750hz, and another tone in the typical 'bell' range.

I have a few ways of generating 750hz from a portable device, but no noise cancelling headphones (of my own) for testing.

Show threadSupermoosie1d ago

@dec23k @moz

Or a 115 decibel bike air horn will just over power their headphones, make them jump 4 ft in the air and shit themselves.

https://www.ansco.com.au/air-zound-xl-bike-horn-pet-cannister

Air Zound XL Bike Horn

AirZound is a loud 115db, the Air Zound Bike Horn refills quickly and easily with a bike pump or compressor.

www.ansco.com.au
Show threadDec [{()}]23h ago
@SuperMoosie @moz
Crikey!
But also, that does look like it's intended for use in mostly vehicle traffic.
Show threadSupermoosie

@dec23k @moz

Yes, traffic is what I used to use it for.

But one day a guy wandered across botany road in right front of me. He thought he was about to be hit by a truck.

Apr 8 at 9:46amWeb
Show threadDec [{()}]22h ago

@SuperMoosie @moz
I like how the possibilities in the research included mechanical (possibly wheel-powered) air sirens. I have used a hand-crank air siren; there's a lot of stop and start needed!

But regular DTMF tones played loud over a Bluetooth speaker might be close enough - the number 6 includes 770hz and 1477hz.
The higher tone is just a courtesy to make it sound more like a bicycle bell; it's not critical for ANC.

666 FTW anyone?