Scientific Reports has published a description of a new device that reduces the volume of sounds passing through an open window. It can be installed in two-pane sliding windows and will reduce the volume of outside noise by 10 decibels.
The device consists of 24 small speakers (each 4.5 cm in diameter), assembled in a grid pattern, and one external sensor. When the sensor detects noise outside the window, the speakers emit "anti-noise" at the same frequency - but with inverted sound waves. Thus, anti-noise dampens external sound and reduces the amount of acoustic pollution that enters the room.
In the course of numerous tests, the developers recorded the fact that the volume of sounds passing through an open window was reduced by 10 dB. The experiments used acoustic waves with a frequency higher than 300 Hz, which corresponds to the noise of road traffic and passing trains. The authors of the development hope that their device will enter the market and will be able to actively reduce the level of sound pollution in large cities.