Hugh Pickens DOT Com writes "Industry Tap reports that there is a place so quiet you can hear your heart beat, your lungs breathe and your stomach digest. It's the anechoic chamber at Orfield Labs in Minnesota where 3ft of sound-proofing fiberglass wedges and insulated steel and concrete absorbs 99.99% of sound, making it the quietest place in the world. 'When it's quiet, ears will adapt,' says the company's founder and president, Steven Orfield. '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.' The chamber is used by a multitude of manufacturers, to test how loud their products are and the space normally rents for $300 to $400 an hour. '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.' But the strangest thing about the chamber is that sensory deprivation makes the room extremely disorienting, and people can rarely stay in the dark space for long. As the minutes tick by in absolute quiet, the human mind begins to lose its grip, causing test subjects to experience visual and aural hallucinations. 'We challenge people to sit in the chamber in the dark — one reporter stayed in there for 45 minutes,' says Orfield who says even he can't stand the quiet for more than about 30 minutes. Nasa uses a similar chamber to test its astronauts putting them 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.'"