Anechoic chamber - A quite unfamiliar word right!
It makes the Orfield Laboratories in South Minneapolis, United States the quietest place in the world.
How quiet? 30 db, 20 db or 0 db? Guess…
No, it is minus 9 decibels (-9 db). It’s 99.99% sound absorbent and holds the Guinness World Record for the world’s quietest place.
It achieves its ultra-quietness by virtue of 3.3-foot-thick fiberglass acoustic wedges, double walls of insulated steel and foot-thick concrete.
When it’s quiet, ears will adapt. The quieter the room, the more things you hear. You'll start hearing your heart beat, sometimes you can hear your lungs, hear your stomach gurgling loudly.
You will also start hearing the sound of blood running through your veins and arteries. Guys like Derek Muller have stayed there for an hour and have experienced these kinds of sounds.
Space is like one giant anechoic chamber, so it’s crucial that astronauts are able to stay focussed. NASA uses these types of chambers for training. Astronauts are true heroes right!?