Researchers design a new structure that absorbs all sound

Researchers design a new structure that absorbs all sound: In their work, the researchers have demonstrated how the designed structure achieves extraordinary sound absorption using an apparently contradictory strategy: the sound attenuation increases when the quantity of absorbent material is reduced. This way, a totally reflective surface becomes a perfect absorbent despite the fact that, for the most part, there is no material that absorbs sound.