I never quite realized how noisy an airplane is until I used a set of noise cancelling headphones for the first time.
When I took them off after a nap, I worried that something went wrong. Was there a breech in the fuselage?! What’s that horrible sound?
…oh, the engine.
Basically, in order to make the plane lightweight enough to fly, honeycomb structures are used to maintain the strength while reducing weight.
This membrane, created by a research team at NC state, would reduce the sound without adding the heft that traditional insulation would add.