Most noise-blocking headphones fall into two categories: they use some kind of material to absorb or scatter noise, or they use active cancellation that creates a signal to oppose the noise signal. As you’ve probably noticed, both of these approaches have limitations. Now, Swiss scientists think they have a new method that will work better. In Nature Communications, they describe a noise cancellation system that moves air by using ionization instead of a conventional transducer.
With the cool name plasmaacoustic metalayers, the technique uses a controlled corona discharge to create very thin layers of plasma between a metal grid and thin wires. With no voltage, sound passes freely. Applying a voltage across the assembly produces ions and moves air with very low inertia, unlike a typical speaker. By controlling the reverse pressure of air, the system can cancel incoming noise picked up by a microphone.
Ultimately, this turns out to be like active noise cancellation with a better transducer than the typical speaker. While it isn’t exactly the same, it did remind us somewhat of how electrostatic headphones work.
Will we see better headphones from this work? Too early to tell. But it is an interesting way to create a speaker-like transducer, and it may even have uses other than noise cancellation. If you build anything using this technique, be sure to let us know about it.
Amazon wants to make your noise canceling keyword sensitive. But you can always go cheap and just block outside noise as best you can.
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