As it turns out, there is, and it’s one of the quietest places not only in the city but on the planet. It’s called an anechoic chamber, and it’s tucked away in the Vibration and Acoustics Laboratory at the Cooper Union for the Advancement of Science and Art, in the East Village. One recent weekday afternoon, I set out to experience it.
|41 Cooper Square; photo courtesy of waymarketing.com|
|Mechanical engineering student Keira Li and Professor Melody Baglione with a sound meter in the chamber|
This is because the walls, ceiling, and floor are designed so that sounds produced inside create virtually no echo (hence the term anechoic). For sound researchers and product developers, measurements taken inside constitute a baseline for theoretically ideal acoustic conditions in the real world. This isn’t the quietest anechoic chamber on earth, however: that honor belongs to the chamber at Orfield Labs, in South Minneapolis, which holds the Guinness World Record for the world’s quietest place. Also, they’re not all as tiny as this one. The Benefield Anechoic Facility at California’s Edwards Air Force Base is large enough to hold a fighter jet.
The walls of the chamber are lined in wedges of wire-mesh-covered fiberglass arranged in a checkboard of vertical and horizontal rows. The floor consists of a metal grid set over more foam wedges. Punctured balloons have fallen into the cracks from years of balloon-bursting experiments, which demonstrate the room’s acoustic properties. If the silence isn’t intimidating enough, the wedges appear to loom toward visitors like gaping jaws.
As Professor Baglione explains, “An anechoic chamber is designed to be almost 100 percent absorptive within a specified frequency range. When sound hits a surface, it is either absorbed, reflected, or transmitted. Fiberglass is porous, so when sound impinges on the wedges, it reflects back and forth in the air gaps in the fiberglass and the acoustic energy gets dissipated.”
|One of the fiberglass wedges that line the anechoic chamber and absorb sound|
The wedges’ shape and alternating orientations are intentional. As sound waves approach the V where two wedges meet, they bounce off the sloping wall of one wedge, then the wall across from it, gradually moving toward the juncture where they intersect, by which point all the sound waves have been absorbed. In the real world, the sound waves of the human voice decay after about 0.8 seconds; in here, they decay in .035 seconds.
|The floor of the chamber|
|The chamber’s jawlike door|
For more information on the Cooper Union’s anechoic chamber, please visit its website.