What does silence really sound like? Step inside an anechoic chamber to find out.

Marisa Taylor | July 2008 issue

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-coloured 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 (see also page 80). 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 fibreglass wedges that absorb all sound waves.
The floor of the chamber is covered in wedges too; we’re walking on a springy suspended floor made of cross-hatched wire, with tangles of electrical cords and the same pattern of wedges spanning the actual floor of the chamber a few feet below us. I’m teetering all over the place on the wires, as my boots have kitten heels. I begin to hear a high-pitched ringing in my ears. It’s eerie in here.
As I try to focus on what Hafter is telling me about the architecture of the chamber, I notice my chest starts to feel tight, out of nervousness. What surprises me is our voices don’t sound muffled. For some reason, I’ve pictured our mouths moving but no sound coming out, like we’re in some kind of a sound vacuum.
After a few minutes discussing his research, I tell Hafter I hope to hear some of the auto-emissive sounds I’ve read about. He’s skeptical, because the anechoic chamber isn’t completely attenuated, meaning that it doesn’t totally shut out noises from the outside world, though it does come close. But if I stay still and quiet, he says, “You’ll hear breathing. You’ll hear stomach gurgles. You’ll hear all kinds of stuff.”
On that note, he leaves me to sit down in the lone chair in the chamber and promises I can stay inside the thing for as long as I want. The longest time he’s ever been inside is probably half an hour, but it doesn’t bother him. He’s used to it. “Call me before you come out because I don’t want you to fall,” he says, concerned about my wobbly boots. “Light on or off?”
“Um, on,” I say, giggling nervously.
Before I know it, the door has slammed shut and I’m alone in the dim light. Hafter can hear me from outside the chamber if I speak, but I can’t hear what’s going on in the rest of the laboratory. While it’s comforting to know I can just yell and I’ll be fetched immediately, something about the isolation feels disconcerting.
I try to remain still and quiet, as Hafter has instructed. I become conscious of my own breathing—it sounds loud, clumsy, like Darth Vader. The tightness in my chest has increased and spread to my upper arms. I sit and wait for five minutes, 10 minutes, and still I’ve heard none of these so-called auto-emissive sounds. Why can’t I hear my heartbeat? This is what it must feel like to do hallucinogenic drugs, I think, waiting for the effect to kick in.
After about 30 minutes, I realize I’ve zoned out into some kind of a meditative state, just listening to the rhythmic sounds of my own breathing. I hear an occasional single or double pulse in either ear; perhaps they’re adjusting to the lack of noise? Or is it my heartbeat?
I’m hyper-aware of my body: the occasional gurgle from my stomach, the wheezing sound the air makes as I breathe in and out of my nose. I sense my body temperature has risen slightly, and think how good cool liquid would feel going down my throat.
Some minutes later—at this point, I’m not sure how many—I become a little dizzy. My ears are stifled, like I’ve put on a pair of fluffy earmuffs. I feel completely solitary, as though time has stopped. The scientists know I’m in here, and all I have to do is yell, I tell myself, but I can’t help feeling paranoid. The ringing in my ears and the tightness in my chest are getting unbearable. The pulses in my ears are more frequent, my breath more wheezy.
Unlike John Cage, I don’t feel inspired. In fact, I’ve never felt so alone.
Steve Orfield could probably tell me a thing or to about why the silence has made me so uncomfortable. At his laboratory in Minneapolis, Minnesota, Orfield conducts what he calls “perceptual market research”; in other words, the measurement of sound quality.
From the roar of a Cessna to the rumble of a Harley to the clicking noises coming from your computer’s hard drive, every product makes some kind of noise. Dozens of Fortune 500 companies have come to Orfield Laboratories to figure out, through extensive consumer tests, how the sounds of their products can denote power, or quality, or expense.
But consumer testing is only part of the picture at Orfield Labs. On the grounds of his facility, complete with auditorium, acoustic simulation lab and reverberation room, is an anechoic chamber that Guinness World Records has deemed “the quietest place on Earth.”
This dubious distinction wasn’t something Orfield ever planned when he opened the laboratory as an architectural and lighting consulting firm in 1971. He stumbled into sound quality research during the dour economic times of the 1970s after realizing his business might not survive. Years later, he purchased the anechoic chamber from the Sunbeam Corporation in Chicago, Illinois. “It’s as if you are sitting in a room that was lined with a foot of fabric on all sides—the floors, the ceiling and the walls—there’s just nothing to create a reflection,” Orfield explains.
But this particular anechoic chamber is special, and much more sound-tight than the facility in Berkeley. The six-sided room floats on springs in a concrete pit, which is surrounded by another chamber, which is surrounded by another concrete structure that’s about three metres (10 feet) thick. When the manufacturer of the chamber took a sound measurement of –9.64 decibels, he decided to contact Guinness, and, well, the rest is history.
Orfield emphasizes that in technical terms, the quietest place on Earth, like Cage’s symphony, isn’t actually silent. It’s really just a place where sound can’t reverberate—the opposite of, say, a cathedral or a sports arena. Still, the Guinness distinction warrants that people often want to come by and visit. If nothing else, it’s a study in sensory deprivation.
“We’ve offered to give anybody who will sit in there for 45 minutes in the dark a case of Guinness,” Orfield explains. “But no one’s ever taken us up. People are kind of frightened of the room.” Even he won’t do it. “If I sat in there for a half an hour, I would be uncomfortable. If I did it 10 times in a row, I would still be uncomfortable.”
While I’ve beaten steve orfield’s record time, I was no less frightened of the room for having stayed in it so long. Plus I had to leave the lights on.
Gerry Popelka, chief of audiology at Stanford University’s School of Medicine in California, and inventor of the digital hearing aid, can explain why silence is so spooky. The ears don’t make any kind of physical adaptation to it, he says. And people are so accustomed to excessive noise that it just feels odd to be in a place that eliminates reverberation or outside noise, like an anechoic chamber, because no one ever experiences it.
“We walk around in environments that are naturally noisy,” Popelka says. “And as we live in more mechanized societies, there’s even more noise. Now you remove all of that noise and you have a different sensation. But your ears didn’t change at all. The idea of hearing your own blood rushing through your arteries is odd. It’s only odd because you haven’t listened to it before. But it’s always been there.”
Moreover, Popelka continues, there’s an emotional and psychological reaction connected to such a dramatic change in the sensory environment. It’s kind of like having a fear of climbing to the top rung of a ladder, only to practise it a bunch of times and find your bones didn’t become less brittle as you practised; you just became less afraid of falling and hurting yourself. The shock to my system, then, has to do with the fact that I’m not accustomed to this form of silence.
“Hearing is strongly associated with language and communication,” says Popelka, “but it also connects us with the environment.” Being cut off from that environment so completely is, well, scary.
Experts like Orfield and Popelka say young people today will likely suffer from more severe hearing loss than their Baby Boomer parents, simply because they’ve grown up in the era of the Walkman and the iPod. And the more damage to the ears that occurs from wearing ear buds or headphones, the more a listener will turn up the volume, rather than adjusting to a lower volume based on diminished hearing abilities. With advances in technology and a constant need for convenience, perhaps younger generations face a whole new concept of silence—or, rather, a whole new concept of noise.
After spending more than an hour in the Berkeley anechoic chamber, I’m in a daze for the rest of my visit to the laboratory, until I’m able to bound up the concrete stairs and burst through the doors into the sunlight. As hyper-aware as I’d been of my breathing and the muted sensation in my ears inside the chamber, I feel equally aware now of the sounds of people’s voices and cars driving by.
In fact, I’ve never been so thankful for noise, glorious noise.
Having come of age at a time when silence wasn’t golden but a sign that your Walkman was out of batteries, maybe I’m less in tune with unheard melodies. However hard peace and quiet are to come by these days, I’d probably miss the hum and buzz of daily life even more. The beauty of silence is in the ear of the beholder.
Marisa Taylor is a freelance journalist who lives in San Francisco.