Orfield Laboratories” “anechoic chamber” in the U.S is 99.99% sound absorbentVolunteers see hallucinations after a short while. They say silence is golden – but there’s a room in the U.S that’s so quiet it becomes unbearable after a short time.

The longest that anyone has survived in the ‘anechoic chamber’ at Orfield Laboratories in South Minneapolis is just 45 minutes.

It’s 99.99 per cent sound absorbent and holds the Guinness World Record for the world’s quietest place, but stay there too long and you may start hallucinating.

The Anechoic Test Chamber at Orfield Laboratories was deemed the quietest place on Earth in 2004 – a record it still holds to this day

It achieves its ultra-quietness by virtue of 3.3-foot-thick fiberglass acoustic wedges, double walls of insulated steel and foot-thick concrete.

The company’s founder and president, Steven Orfield, told MailOnline: ‘We challenge people to sit in the chamber in the dark – one reporter stayed in there for 45 minutes.

‘When it’s quiet, ears will adapt. The quieter the room, the more things you hear. You”ll hear your heart beating, sometimes you can hear your lungs, hear your stomach gurgling loudly.

‘In the anechoic chamber, you become the sound.’

And this is a very disorientating experience. Mr Orfield explained that it’s so disconcerting that sitting down is a must.

He said: ‘How you orient yourself is through sounds you hear when you walk. In the anechnoic chamber, you don”t have any cues. You take away the perceptual cues that allow you to balance and manoeuvre. If you”re in there for half an hour, you have to be in a chair.’

The chamber is used by a multitude of manufacturers, which test how loud their products are.

MrOrfield said: ‘It”s used for formal product testing, for research into the sound of different things – heart valves, the sound of the display of a cellphone, the sound of a switch on a car dashboard.’

Silence is not so golden: The longest anyone has lasted sitting alone in the dark in the chamber is 45 minutes

It’s also put to use to determine sound quality.

Mr Orfield and his team will help companies such as washing-machine maker Whirlpool develop metaphors for what sound should, well, sound like.

Motorbike maker Harley-Davidson used the lab, for instance, to make their bikes quieter, while still sounding like Harley-Davidsons.

‘We record products and people listen to them based on semantic terms, like “expensive”, “low quality”, said Mr Orfield. ‘We measure their feelings and associations.’

Nasa, meanwhile, uses a similar chamber to test its astronauts.

They are put in a water-filled tank inside the room to see ‘how long it takes before hallucinations take place and whether they could work through it’.

As Mr Orfield explains, space is like one giant anechoic chamber, so it’s crucial that astronauts are able to stay focussed.

Mr Orfield admits that he can last a very respectable 30 minutes in his chamber, despite having an off-putting mechanical heart valve that suddenly becomes very loud indeed once he”s inside.