Videos of pedestrians being hit by cars, motorbikes and bicycles because they didn’t hear the horn or bell have gone viral on social media. All because they were wearing headphones and earphones with active noise cancellation (ANC). This is why many audio accessories now have a pass-through mode to prevent this “accidental deafness” incident that endangers safety.
Czech automotive company Skoda Auto has developed the DuoBell bicycle bell, which is specifically designed to pass through the ANC system of audio accessories. In their study with scientists from the University of Salford, sounds at frequencies of 750–780 Hz cannot be filtered out by all ANC systems. So the DuoBell bell is designed to ring at this frequency.
Meanwhile, the bell has a secondary echo chamber and an uneven hammer mechanism to produce a sound pattern that is difficult for ANC to block. In real-world tests using Deliveroo delivery partners on bicycles, the bell’s ringing could be heard up to 22 metres away or 5 seconds earlier. This allows pedestrians to avoid being hit by a bicycle.
The Skoda DuoBell is just a prototype and is not for sale to the public at this time.
