On: Sound-suppressing silk can create quiet spaces

[ghusbands]

That's active electronic noise cancellation - there have been many of those described and very few delivered over the past thirty years. Presumably because it's the sort of thing that is angle-sensitive and hard to set up and maintain.

The thing I saw was just a pane of glass or plastic with large round holes in it to attenuate/dissipate sound waves while allowing significant airflow.