The silk sheet from the article is a loudspeaker. The solution proposed in the article requires a microphone, and would have a tough time dealing with multiple

The silk sheet from the article is a loudspeaker. The solution proposed in the article requires a microphone, and would have a tough time dealing with multiple sources. It basically records the room, then plays the room back via the silk sheet, but out-of-phase. Because it's out of phase, it cancels out.