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RetroScience: The World's Quietest Room

The Secret Life of Scientists and EngineersThe Secret Life of Scientists and Engineers

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Want to travel back in time? In our weekly “Retro Science” series, we’re digging up visual artifacts that capture fascinating moments from science history, including surprising studies, outdated inventions, and breakthrough achievements. By recapturing science’s impressive feats and most amusing flops, RetroScience will remind us of how far we’ve come, and how far we have yet to go.

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1940: A Bell Laboratories scientist performs an acoustic experiment in the Murray Hill Anechoic Chamber.

This room may look like a modern art installation, but its stunning design actually has a unique purpose: to block out as much sound as possible. Built in 1940 by Bell Laboratories in Murray Hill, New Jersey, this chamber was then considered the world’s quietest room. The chamber was ‘anechoic,’ meaning ‘without echo,’ absorbing over 99.995% of the incident acoustic energy above 200 Hz. Large fiberglass wedges were mounted on the walls absorbed sound reflections. Thick cement and brick walls surrounded the exterior, blocking out outside noises. The room floated above a sunken pit, resting on a shock absorbing wire grid to negate any external vibrations.

The first of its kind, the Murray Hill wedge design is still used today in anechoic chambers around the world. The chamber has been used to test sound and electromagnetic equipment, perform psychoacoustic experiments, and even simulate concert hall acoustics, as shown below. Research in the chamber also led to the establishment of the standard loudness contours that we use today.


A scientist takes psychoacoustic measurements relating to loudness in the Murray Hill Anechoic Chamber.

Original funding for "The Secret Life of Scientists and Engineers" was provided by the Alfred P. Sloan Foundation.