In theory, noise-canceling headphones are a brilliant idea. That is, until the "noise" you're blocking becomes important. Whether it's an ambulance siren or somebody shouting your name, some sounds are meant to be heard.
Amazon has a solution. The company just won a patent for noise-canceling headphones that are capable of letting certain sounds in. Just as the Echo smart speaker actively listens for you to say "Alexa" (or "Amazon"), the microphones on Amazon's proposed headphones could keep a virtual ear out so you're not left blissfully rocking out to Katy Perry as life-threatening danger–or your boss–approaches.
[Image: U.S. Patent and Trademark Office] JPT