Right? This feels like an "arms race" similar to scraping vs. anti-scraping; countermeasures will be developed, likely due to the action of actors entirely disconnected from what you're doing, but to block something else in the ecosystem... and you'll need to re-engineer your approach entirely. Rinse and repeat.
(The amount of innovation in anti-anti-scraping that's resulted from "sneaker bots" - automated scalping of limited-edition shoe releases - is astounding, and somewhat relevant here in how an environment can become adversarial in ways that impact broad ecosystems. I suppose the equivalent here would be environmental ads that seek to penetrate noise-cancellation in a similar way.)
I suppose, though, that all this is good news for a company that wants to turn your bicycle bell into a subscription product!
I think there's a broader indication of an arms race between noise cancellation systems and things that want to be heard, like advertising. And this just-happening-to-exist bandpass that the DuoBell is depending on could easily become collateral damage in that fight.
I was going to make a joke about advertisers working in some kind of ultrasonic modulation to their audio so it breaks ANC (I'm aware this wouldn't really work) but then thought, whats more likely, advertisers doing that, or advertisers partnering with 80% of ANC chip makers to just let them by-pass with specific tone markers...
Then we'll be hacking our headphones with specific 3d printed clip-ons that involve a particular brand of coffee filters that happen to attenuate the "clear freq" enough for the headphones to miss it.
(The amount of innovation in anti-anti-scraping that's resulted from "sneaker bots" - automated scalping of limited-edition shoe releases - is astounding, and somewhat relevant here in how an environment can become adversarial in ways that impact broad ecosystems. I suppose the equivalent here would be environmental ads that seek to penetrate noise-cancellation in a similar way.)
I suppose, though, that all this is good news for a company that wants to turn your bicycle bell into a subscription product!