One of the most significant innovations in personal audio has been noise cancellation. With the tech now ubiquitous in headphones and even earbuds, we find ourselves eliminating noise bleed, improving the sound of our audio, and even finding it easier to sleep on planes.
However, noise cancellation has its drawbacks too. Most prominently, the elimination of environmental sounds can cause hazards for pedestrians with their headphones on as they can’t hear automobiles or bicycles passing by. And in a world where we’re disconnecting more and more, increased obliviousness isn’t necessarily a good thing.
Coming out of the Czech Republic, Škoda Auto has a solution, at least a small one, for cyclists who just want to get your attention. It’s a bell that cuts through your ANC headphones, and the tech has just been open-sourced.
Back to the Beginning
Before Škoda was building Octavias and Kodiaq SUVs, it was building bicycles. Václav Laurin and Václav Klement launched their Slavia bicycle brand in Mladá Boleslav in 1895, and the company didn’t pivot to cars until a decade later.
The Frequency Fix
The DuoBell came out of a collaboration between Škoda’s U.K. team, creative agency AMV BBDO, and acousticians at the University of Salford. They figured that standard bike bells get filtered out by ANC systems because those systems generate counter-sounds that cancel incoming audio signals. The research team went looking for a gap, and they found one, a narrow frequency band between 750Hz and 780Hz that consistently slips through ANC filters.
The bell itself is entirely mechanical, meaning no battery or electronics. What separates it from a standard bell is a second resonator tuned to a higher frequency, paired with a striking mechanism that produces rapid, irregular impacts rather than a clean, predictable ring since ANC algorithms have a harder time locking onto and canceling erratic sound patterns. The result, per Škoda’s two-week trial with Deliveroo riders in busy London streets (where reportedly 54% of headphones sold have noise cancellation), is that pedestrians wearing ANC headphones could react up to five seconds sooner and from 22m (~72ft) farther out than with a traditional bell.
The dual-tone design also covers non-headphone wearers, with the higher resonator doing the work for anyone simply walking around sans accessory.
Up for Grabs
This is still a prototype. Real-world conditions vary considerably from controlled trials, and ANC technology continues to evolve rapidly. What defeats today’s headphone algorithms may need recalibrating against tomorrow’s.
Škoda has been transparent about this, publishing their findings as an open-source white paper rather than keeping the tech under wraps. This allows any company out there to make their own bike bell or otherwise that will contribute to the safety of both pedestrian and cyclist. As of now, the DuoBell isn’t headed to retail, but the research is out there for other manufacturers to run with.
Spec Sheet
Model: Škoda DuoBell
Type: Mechanical bicycle bell (no battery or electronics)
Technology: Dual-resonator system; secondary resonator tuned to 750–780Hz ANC-penetrating frequency band; irregular-strike hammer mechanism
Developed With: University of Salford, AMV BBDO, PHD Media, Unit 9
Performance: Pedestrian reaction time improved by up to 5 seconds; audible up to 22m further than standard bells
Release Status: Prototype; research published as open-source white paper
Pricing & Availability
The DuoBell is currently a prototype and isn’t slated for commercial release yet. Škoda has made the underlying research publicly available, so the road from concept to something you can actually bolt onto your handlebars depends largely on whether the broader cycling industry picks it up.
Recap
Škoda DuoBell
Škoda built a fully mechanical bike bell that actually cuts through noise-cancelling headphones by targeting a frequency gap that ANC systems can’t block. Still just a prototype, the Czech brand has open-sourced its findings for others to manufacture.
