Microsoft has broken a Guinness World Record (another one!) to become officially recognised as home to the quietest room on Earth. Staff at the company’s Redmond, Washington campus in the USA, beat the standing record of minus 13 dB(A), earlier this month, after the company’s anechoic chamber proved to have an ambient background noise level as low as minus 20 dB(A).
Tests were carried out with assistance from measurement expert, Brüel & Kjær, which provided Microsoft with instrumentation and analysis software to assess the room, including a LAN-XI 3050-A-060 data acquisition module, the Type 2831 LAN-XI battery, two low-noise Type 4955 microphones, the Type 7708 Time Data Recorder, and Brüel & Kjær’s PULSE Software.
Alongside personnel from BlackHawk Technology, Brüel & Kjær used a special, two-microphone coherent power measurement technique to achieve the extraordinarily low ambient noise level measurement.
Microsoft’s Dr Hundraj Gopal, Speech & Hearing Scientist, Human Factors Engineering commented: “Anechoic chambers are special rooms containing sound-absorbing and sound attenuating material in the walls, ceiling and floor that are designed to absorb 99.99% of the sound, ensuring the space is free from echoes. 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.”
Following the successful tests, David Formenti, BlackHawk Technology and Vince Rey, Brüel & Kjær said: “The Brüel & Kjær high-quality transducers, data acquisition system and analysis software make a unique tool for these high performance measurements. Using these tools, we were able to repeat the ambient noise measurements - in the chamber - multiple times. It was a great experience and opportunity to be able to apply these special measurements and signal processing techniques, to prove that Microsoft had beaten the world record for the quietest place on earth in their anechoic chamber!”