Allowing free flow of air while simultaneously blocking/ absorbing >86% of sound across frequency spectrum from 300 to 6000 Hz

https://techxplore.com/news/2026-02-physics-principle-absorption-barriers-ventilated.html

"sound-absorbing foam/ fiber solid/ porous blocks ventilation, overcome with destructive interference balancing structure's monopole/ dipole resonances... traps sound waves, causing dissipation into heat... Figure of Merit evaluates absorption bandwidth/ material thickness/ air channel openness relationship... jet engine roar reduction while maintaining intake/ exhaust efficiency, silent fans/ heat sinks for computers/ servers, noise barriers for highways/ tunnels allowing natural wind passage/ preventing heat buildup"