Mastodawn

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 thread

Slash909uk 1d ago

@dec23k interesting.

From the paper I understand the 750Hz tone is around 3dB less attenuated, but only in quiet areas with already not much noise, like parks.

In noisy areas, any tone that is distinct from the noise is more easily heard. But everything is attenuated and the warning distance is considerably lower already.

I wonder if these ANC headphone makers are obliged to support 'emergency' vehicle tone detection and not blank it out? Does anyone know?

Or there is the air horn solution🤪

Show thread

Dec [{(

)}]

@Slash909uk
Regular DTMF tones (played loud) might be close enough - the number 6 includes 770hz and 1477hz.

The higher tone is a courtesy to make it sound more like a bicycle bell, so it's not critical for getting past ANC.

666 FTW? Anyone?