EPFL researchers have developed a 100% effective, ultra-thin active noise cancelling system that uses an ionized air plasma propulsion system instead of speakers. A 17mm (0.6 inch) thick layer can block 20 Hz noise as well as a 4m (13 ft) thick wall.
I wonder if there’s a limit to how loud of sounds it can cancel? Can I have a mini rave in my garage without bothering my neighbors (I mean other than the chill out area forming on their lawn).