Inside The Quietest Place On Earth

Our intrepid correspondent PAT PILCHER gets to hear his eyeballs move in a freaky alternate universe.

I’d never heard of an anechoic chamber. I certainly never expected to go inside one, let alone one that holds the world record for being the quietest place on earth.

The first thought that popped into my mind as I stepped in was: “What on earth is this anechoic chamber business, anyhow?” It turns out that an anechoic chamber isn’t the name of a weird 1980s new wave band, but is a sound-proof room that’s designed to absorb and deaden reflected sound.

This chamber is located in Microsoft’s mysterious Building 87, located on their vast Seattle campus. I say mysterious, because Building 87 is Microsoft’s top secret skunkworks. It’s where all their hardware gets designed, prototyped and tested. It’s also difficult to get access. Most Microsoft employees will never get to see inside of it.

The measures Microsoft took to ensure that their anechoic chamber is utterly silent are boggling. According to our guide, Dr Hundraj Gopal, the chamber is kept physically separate from the rest of Building 87. This ensures vibrations from any nearby foot and road traffic don’t create any noise. It also means there’s an air gap between the chamber and Building 87. Entering it requires crossing a small bridge.

To further isolate the chamber, it also sits on a bed of spring loaded shock absorbers. These kill stray vibrations. The air ventilation system has also had the silent treatment. All of its ducting uses baffles and sound absorbent coatings.

The chamber itself is quite striking. Its walls are lined with thousands of wedge-shaped baffles. We step onto a wire mesh floor. It’s there to ensure we don’t damage the floor baffles. It feels a lot like walking on a trampoline.

Once inside, audio levels drop to an inaudible -20.6 decibels. Short of being in a vacuum, -23 decibels is the theoretical lowest audio level possible. My voice sounds flat and a lot smaller. Conversation feels weird.

Our guide challenges us to stay in the chamber for five minutes with the lights out and the door closed. Once the airlock/bank vault-like door closes and the lights goes out, it’s dead silent; not just quiet, but absolutely and eerily silent. The effect is surreal. It’s a lot like what I’d imagine floating in space must be like.

It turns out that in a quiet environment your brain and ears adapt. So, the quieter things became, the more I could hear. Within seconds of the lights going out, the silence was deafening. I could hear my heart beating, my breathing, my stomach gurgling. Even moving my eyes made noises I’d never heard before (or hope to ever hear again).

So, why does Microsoft need such silence? The answer’s simple: they use it to test their keyboards and mice to ensure that they make a proper and satisfying click sound. The cooling fans used in their Surface computers are also tested to ensure they don’t make any unpleasant whirring/whining noises. The chamber is also used for testing their digital assistant, Cortana. Because the chamber is a about as close to a perfectly controlled audio environment as possible, Microsoft can introduce ambient noises and accurately test Cortana’s speech recognition capabilities in different acoustic environments.