Perhaps two sheets of material, one that acts as a high resolution two dimensional microphone array, the other that acts as a high resolution two dimensional sp

Perhaps two sheets of material, one that acts as a high resolution two dimensional microphone array, the other that acts as a high resolution two dimensional speaker array with the microphone array a fixed distance from the speaker array. The microphone array detects sounds, the distance between sheets equals the processing delay as it relates to the speed of sound, and the speaker array cancels the wavefronts. Maybe two layers of microphone arrays would be needed to estimate the angle of arrival of the sound pressure fronts. That wouldn't help the problem of sound that travels through walls, ceiling and floor to the other half of the room (or to a different room). You'd need sound cancelers in front of or behind every room surface in every direction, and bass traveling through a floor seems difficult to stop since it would require a lot of energy. Still, a vibration isolated bed with these magic sound canceling sheets surrounding it might be fairly effective. Letting the sound of smoke alarms, air raid sirens, police sirens, etc. through in emergencies could be an issue. Sounds expensive using today's technology though, one sheet might require a fair amount of computer processing for say a 10,000 x 10,000 array of microphones and the same size speaker array. Starting with proper sound isolating construction might be cheaper. Though if mass produced the cost may eventually go down a lot. It doesn't necessarily have to solve all sound problems, just the ones some people find annoying. Perfect silence is in fact fairly spooky and freaks some people out (if you've ever been in an anechoic chamber).