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

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Joan of Contention 😷14h ago

@dec23k

So, in the use-case scenario here, I'm on my bike, and I see that there's a person walking/wheeling ahead of me and they're wearing noise cancelling headphones.

Question:

Why do I need a bell?

Assumptions:

(a) If they're ahead of me and in my path, I'm either on a footpath, shared path, or carriageway;

(b) I have seen them.

Answers:

(b) I have seen them;

(a) If I'm on a footpath, I need to move; if I'm on a shared path, I need to wait; if I'm on a carriageway, I need to wait.

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Sam

@clickhere @dec23k My use case for bells is that there are people ahead of me walking in the road, and I want to let them know I'm there when I'm far enough away that I won't startle them when passing politely (assuming it is safe to do so). Some people prefer a bell to a call -- sometimes a bell announces "bicycle" rather than "runner" in a way people prefer.

I don't cycle on paths or the pavement.

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Joan of Contention 😷6h ago

@ravenbait @dec23k Oh yeah, in general, I use a bell now and then, in a fairly similar way.

But if I see that someone has noise cancelling headphones - or otherwise doesn't seem to have reacted to the sound of the bell (they may be deaf or hard of hearing) - then I'll adjust what I'm doing. (Like, I won't barge past, usually just take my time and wait for an opportunity to pass safely.)

But this over-engineered, highly specific use-case? Nah.