Is this thing on? That’s likely what Hong Kong University of Science and Technology scientists thought, shortly after they’d developed a new system that absorbs 99.7 percent of all the sound that hits it.
Many systems use sonic insulators to deaden sound: materials which absorb sound, typically over a small range of frequencies. By combining different insulators into a composite, it’s possible to absorb a large range of sounds — but it’s difficult to create such a material that absorbs all the the frequencies. It would just be too big and complex. That means that there’s a limit to the amount of sound they can absorb.