Engineers create synthetic, sound-silencing structure that blocks 94% of sounds (Eurekalert)

Boston University researchers, Xin Zhang, a professor at the College of Engineering, and Reza Ghaffarivardavagh, a Ph.D. student in the Department of Mechanical Engineering, released a paper in Physical Review B demonstrating it's possible to silence noise using an open, ringlike structure, created to mathematically perfect specifications, for cutting out sounds while maintaining airflow.

https://www.eurekalert.org/pub_releases/2019-03/bu-brd030619.php
https://news.ycombinator.com/item?id=20377496