The Daily Circuit

In Minneapolis, the world's quietest room

by Tom Weber, Minnesota Public Radio

10:50 AM, April 3, 2012
10:45 AM, June 21, 2012

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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."

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