TL;DR Skoda has developed the DuoBell, a mechanical bicycle bell designed specifically to be heard through noise canceling headphones. Research identified a frequency “gap” between 750Hz and 780Hz where ANC algorithms are least effective at suppressing external noise. The bell also uses a dual-resonator system and an irregular striking mechanism, helping prevent ANC algorithms from processing and blocking the sound. Active Noise Cancellation (ANC) has gotten really good on headphones and earphones.

As more and more users upgrade to newer products with even more effective ANC, there’s a growing second-order effect: people are becoming inattentive, especially when walking on the street, increasing their chances of colliding with cyclists whose mechanical bells are no longer effective.

Czech car manufacturer Skoda (which started off by manufacturing bicycles) is tackling the ANC menace with the new Skoda DuoBell, the first bicycle bell designed to penetrate ANC on headphones. The Skoda DuoBell is a fully mechanical bell that deceives ANC algorithms and significantly increases the likelihood that pedestrians will detect its sound. Through acoustic testing, Skoda and a group of scientists from the University of Salford identified a narrow frequency band between 750Hz and 780Hz where ANC is least effective. The DuoBell can emit sound at this frequency. To further enhance its efficacy, the DuoBell also features an additional resonator tuned to a higher frequency.

There’s also a specially designed hammer mechanism that delivers rapid, irregular strikes.

Combined, the DuoBell generates sound waves that ANC algorithms cannot process quickly enough to suppress. Perhaps most impressively, Skoda has documented the entire process, from lab testing to live street trials, and has opened it up to everyone. You can download the research from Skoda’s website to learn more. Given the ever-increasing popularity of ANC headphones and earphones, such simple, mechanical gadgets are the need of the hour.

However, it wouldn’t be surprising if audio companies further improve their ANC to reduce and eliminate the safety gap. For the safety of all involved, I hope the entire industry comes together to agree and maintain such a “safety gap” for the safety of all consumers. Thank you for being part of our community. Read our Comment Policy before posting.