The longest that anyone has survived in the anechoic chamber at Orfield Laboratories in South Minneapolis is just 45 minutes.
It’s 99.99 percent sound absorbent and holds the Guinness World Record for the world’s quietest place.
It achieves its ultra-quietness by virtue of metre-thick fibreglass acoustic wedges, double walls of insulated steel and 30cm-thick concrete.
The chamber is used by companies all over the US, including NASA, which tests its astronauts there by floating them in a water-filled container to see how long it takes before hallucinations take place and whether they can work through it.
The chamber is also used by a multitude of manufacturers to test how loud their products are.
Harley-Davidson used the lab to make their bikes quieter, while still sounding like Harley-Davidsons.
