What Does Silence Really Sound Like?

By Marisa Taylor, Ode. Posted July 19, 2008.

The sky is bright and cloudless: another perfect day in the San Francisco Bay Area. But I'm about to spend part of it inside a windowless, soundless room called an anechoic chamber in an attempt to experience what silence is really like -- and to find out whether it even exists at all.

The word "anechoic" means "without echoes," and an anechoic chamber -- the walls of which are generally lined with wedges of foam to prevent reverberation -- is a room that prevents echoes of the sounds made inside it. Anechoic chambers are used to test microphones and other audio equipment, but the lack of reverb creates a peculiar effect on the ears. They feel stuffy and plugged because, in jarring contrast to the noise encountered throughout the day, the ears aren't getting any feedback from the environment. After sitting in a confined space devoid of echoes for long enough, some people report hearing their own heartbeats, respiration and other bodily functions, a phenomenon termed "auto-emissive noise."

I have to admit I haven't spent much time thinking about silence. With so much noise in the form of honking horns and ringing cellphones plaguing us in everyday life, who has the time -- or the opportunity -- to listen, to wonder what it would be like if the only sound you could hear were your own heart beating? Moreover, who really wants to experience complete silence?

I've heard from others who've spent time in anechoic chambers that it's creepy. It can make you kind of crazy.

So it's with a sense of apprehension as well as excitement that I journey across the Bay Bridge from San Francisco to visit the laboratory of retired University of California, Berkeley psychology professor Ervin Hafter to see the anechoic chamber his team uses for research.

As I approach Tolman Hall, a building nestled among pine trees on a serene corner of the U.C. Berkeley campus, hordes of carefree co-eds spill out the door, finished with morning classes and on their way to lunch. I leave the pleasant sunlight behind and fight the stream of students to enter the building.

Descending a gloomy concrete stairway, I find myself in a grey basement. I'm buzzed into Hafter's subterranean laboratory, and a research assistant leads me down a hallway and into the main office, where a mess of computer equipment and piles of papers dominate the windowless room lit by fluorescents. I'm a bit taken aback by the sterile surroundings and the isolated atmosphere of the basement.

The assistant introduces me to Hafter, who's tall, with solemn brown eyes and wild, wiry tufts of grey hair sprouting from the sides of his head. His khaki-colored button-down shirt still has the fold marks in it. Since 1966, Hafter has studied auditory perception, spatial hearing and the effects of reverberant environments on users of hearing aids and cochlear implants. The anechoic chamber, along with a highly complicated set-up of computer programs and speakers, is required to test human subjects in his laboratory.

"There is no such thing as zero when it comes to sound," he explains as he leads me to the chamber. While zero decibels is technically demarcated as the threshold for the human ability to hear sound, some people can decipher sounds in the negative decibel range. The lack of echo in the anechoic chamber won't change that. The shaggy-haired research assistant, Swapan Gandhi, a musician, tells me he likes being in the chamber because "you hear things that you don't normally pay attention to," like the sound of your own pulse.

Such was the experience of the late avante-garde American composer John Cage, whose trip to the anechoic chamber at Harvard University in Boston, Massachusetts, was the inspiration for his most revolutionary work -- 4'33'', in which a pianist sits silently before a piano for four minutes and 33 seconds. Cage later wrote of his experience that he "heard two sounds, one high and one low. When I described them to the engineer in charge, he informed me that the high one was my nervous system in operation, the low one my blood in circulation."

In Cage's piece, not one musical note is played. Instead, the audience is left to revel in its own subtle sounds and to realize, perhaps, that silence doesn't actually exist.

I'm a musician myself, so Cage is on my mind as Hafter heaves open the door of the chamber, which is about six feet wide and resembles some sort of meat locker. Dim light emanates from two bulbs dangling on either end of the ceiling. My ears immediately feel plugged, as if they've been stuffed full of cotton, probably because the walls and ceiling are lined with rows and rows of fiberglass wedges that absorb all sound waves.

See more stories tagged with: noise pollution, sound, silence

Marisa Taylor is a freelance journalist who lives in San Francisco.

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