在煩囂都市生活的人，常想渴望有寧靜空間，但原來若待在全球最靜的密室中，感覺並不好受，更會出現幻覺，人類最高極限為僅能在這密室中捱過45分鐘。
美國南明尼阿波利斯有一間獲健力士世界紀錄評為全球最靜的密室，以3.3呎厚的玻璃纖維吸音楔、雙層隔音鋼板和1呎厚石屎製成，能99.99%靜音，待久了會產生幻覺，最高紀錄是有人能在密室捱45分鐘。
聽到心跳肺起伏胃發響
研發人奧菲爾德（Steven Orfield）表示：「我們邀請挑戰者坐在黑暗的密室中……當一切寂靜一片時，耳朵會適應環境，當周遭環境愈靜，你能聽到的愈多。你會聽到自己的心跳， 有時你還能聽到肺部的起伏和胃部的響聲。在密室中，你是一切聲響的來源。」奧菲爾德稱，這是一個很迷失的經驗，使人倉皇失措，必須坐下才能捱過。
可訓練太空人集中力
這間最靜密室用途多多，除了能讓商戶測試產品聲效和音量外，還可讓美國太空總署的太空人在密室中訓練他們的集中力。
This morning, we're talking about noise pollution and the negative health affects it can cause. In Minneapolis' Seward neighborhood, you can find the world's quietest room.
The room, which holds the Guinness World Record designation, is located in the Orfield Laboratories. The recording studios where "Funkytown" and Bob Dylan's "Blood on the Tracks" were recorded are also in this building.
The world's quietest room is called an anechoic chamber, which means there is no echo as it absorbs sound. Sound doesn't bounce off the walls the way it does in a regular room.
A typical quiet room you sleep in at night measures about 30 decibels. A normal conversation is about 60 decibels. This room has been measured at -9 decibels.
Orfield Labs uses the room to test products, including switches that go on car dashboards and the sound an LED display makes on a cell phone to make sure they're not too loud.
To get into the anechoic chamber, you go through two bank vault-like doors. The floor in the room is mesh like a trampoline so there's nothing on the floor for the sound to bounce off of. The walls are lined with sound-proofing wedges that are a meter long so they absorb the sound.
"When you sit in any rooms a person normally sits in, you hear the sound and all its reflections," said Steven Orfield, president of Orfield Labs. "When you go into an anechoic chamber, there are zero reflections. So if you listen to me talk and hear my voice, you're hearing my voice exactly. And if I turn around and talk, the only thing you'll hear is the sound bending around my head."
