REDMOND, WASHINGTON – Within the walls of building 87, located at Microsoft’s headquarters near Seattle, Washington, you will find a very quiet room. The room is so quiet, in fact, that it was just deemed the Quietest Place on Earth from the Guiness Book of World Records.
In two independent tests, the room measured an unbelievably quiet -20.1 dBA and -20.6 dBA. An impressive feat, considering that its creators were hoping for -16 dBA.
The new record beats out one previously held for several years by Orfield Labs in Minneapolis where, among other things, hearing aid research is conducted.
Why the Silent Room?
Microsoft’s new super-quiet room is what’s known as an anechoic chamber, meaning that it is a room designed to completely absorb reflections of sound and also be insulated from any exterior sources of noise.
Anechoic chambers have been used for years in a variety of research and development purposes in many different industries, including the hearing industry (for hearing aid and audiological research).
“Microsoft uses these super-quiet acoustically-controlled chambers to test products such as Surface tablets, HoloLens, etc., to make sure that sounds generated by the devices themselves during use, are as quiet as possible.”
Microsoft uses the room as an acoustic research lab for several of its products and components, including speakers and microphones. Currently, the company is using the acoustic lab to test Cortana, the company’s voice assistant—adding background noise in the room while simultaneously asking questions, to measure and ultimately improve upon performance of Cortana.
Impressive New Record
According to Microsoft, the same company who built the previous record-breaking room for Orfield Lab, Eckel Noise Control Technologies, helped create the new room for the company.
Microsoft’s Audio Lab itself actually consists of multiple anechoic chambers, with the largest sitting on top of springs in order to keep the amount of outside noise to an absolute minimum.
Highly specialized instrumentation from Brüel & Kjær was used to analyze and measure the room. A two-microphone coherent power measurement technique was used to achieve the extremely low ambient noise level measurement.
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