The specially constructed chamber is hidden in the depths of Building 87 at Microsoft’s headquarters in Redmond, Washington, where the firm’s hardware laboratories are based. Microsoft’s engineers built the room – known as an anechoic chamber – to help them test new equipment they were developing and in 2015 it set the official world record for silence when the background noise level inside was measured at an ear-straining -20.6 decibels.
To put that in context, a human whisper is about 30 decibels while the sound of someone breathing normally comes in at just 10 decibels.
“It is a very unique experience inside with the door closed,” says Munroe. “When you stop breathing, you can hear your heart beating and the blood flowing in your veins. I don’t stay inside with the door closed very often.”
Richard Gray in BBC.