Hidden deep within Building 88 on the Microsoft campus in Redmond, Washington, lies what’s officially certified to be the quietest room in the world.
In 2015, an anechoic chamber on the campus of Microsoft broke the world record with a measurement of −20.6 dBA.
The human ear can typically detect sounds above 0 dBA, so a human in such a chamber would perceive the surroundings as devoid of sound. Anecdotally, some humans may not like such quietness and can become disoriented.
Once the door to the chamber is sealed, you immediately notice the difference: Your voice stops carrying, at all, because it’s not bouncing off the walls. All background noise totally fades out. Just talking normally felt like shouting into a pillow, as the noise barely traveled at all.