How does it work

The new technology does not use ordinary speakers, as is often the case in similar situations – the developers used an ionized air plasma unit. A 17-millimetre (1.7-centimetre) layer of air can block out noise at 20 Hertz, as well as a 4-meter-thick sound-absorbing foam wall!

First, it’s worth understanding how active noise canceling (ANC) works. The idea of ​​this process is that microphones measure the sound waves, and then the system produces the same pressure waves in the opposite direction and plays them through the speaker. At the same time, the new wave extinguishes the old one. But part of the sound always passes.

The main idea in the new design was to overcome the heavy weight of the membrane in the speakers so that anti-phase could be produced more flexibly and quickly. Therefore, in their design, the engineers replaced the membrane with ionized air, which was previously placed between the electrodes. As a result, air particles can respond to commands and interact with sound vibrations.

These columns work as ion thrusters, using an electric field to ionize the surrounding air into a plasma, creating positively and negatively charged particles. These ions are then accelerated by a magnet and strike the surrounding air, creating pressure waves. You can instantly change the air jet force by changing the applied voltage.

EPFL has already licensed the described technology. It can be used on the walls of buildings, car bodies and airplanes in the future. But the most important thing is that such a noise suppressor is extremely cheap to manufacture.