The Art of the Anechoic Chamber

Microsoft currently holds the world record for the quietest anechoic chamber, measuring at -20 decibels. The quietest sound in the world is -23 decibels, which is the sound of particles moving. Normal conversation usually occurs around 60 decibels, and the loudest noise in the world is around 170 decibels. Microsoft has their chamber placed in Building 87 in Redmond, Washington. They use the room to test the noise levels of their devices as well as test their personal assistant Cortana. They use the room to control the noises that are distracting the AI so that they can improve it's programming. 

The design of the room includes foam wedges that are specifically placed to absorb sound, not allowing for the natural echo. The main design team consisted of a psycho-acoustician, a sound engineer, and a fiber-optic engineer. Each had pioneered or excelled in their fields of work and were hand selected to design the room. The room is spaced about a foot away from the main walls of the building, standing as it's own little chamber inside a room. The floor of the room is springy, almost like a trampoline, and contains more wedges underneath.