Tours of the facility can be booked through its website , but it warns that visitors cannot be in the chamber alone for any significant amount of time without supervision. Journalists, however, have been left alone there, in the dark. Most lasted for less than 20 minutes, tortured by the absence of noise — apart from the sound of their own bodies.
If you fancy a sound-free session a little closer to home, there is an anechoic chamber at the University of Salford which is open to the public on a few dates each year; definitely worth a Google search I think!
This Microsoft research lab in the city of Redmond, Washington, is officially the quietest place on Earth, according to Guinness World Records. The silent space, created by the tech company for optimal audio and device testing, is an anechoic chamber — a room insulated from exterior sounds and designed to absorb all reflections of sound and electromagnetic waves inside, making it completely echo-free.
So there you have it! The top 10 quietest places on earth. Have you ever visited any of these eerily quiet spaces?
About Latest Posts. Craig Storey. Noise pollution and its effect on people. Cirrus Research plc Visit Cirrus Research for our range of sound level meters and noise measurement instrumentation. We camped at the foot of Kelso Dunes, in a barren, scrubby valley with dramatic granite hills behind us. Virtually no planes flew overhead, and only very occasionally did a distant car or freight train create noise.
Much of the day there was a great deal of wind, but at twilight and early in the morning the winds calmed down and the quiet revealed itself. Overnight I heard the silence being interrupted only once, when a pack of nearby coyotes howled like ghostly babies. Early on the second morning, while I was waiting for Diane to set up some recording equipment, I had a chance to contemplate real silence.
The ear is exquisitely sensitive. When perceiving the quietest murmur, the tiny bones of the middle ear, which transmit sound from the eardrum to the inner ear, vibrate by less than the diameter of a hydrogen atom. Even in silence, tiny vibrations of molecules move different parts of the auditory apparatus.
These constant movements have nothing to do with sound; they stem from random molecular motion. If the human ear were any more sensitive, it would not hear more sounds from outside. Instead, it would just hear the hiss generated by the thermal agitation of the eardrum, the stapes bone of the middle ear, and the hair cells in the cochlea. On the dunes, I could hear a high-pitched sound.
It was barely audible, but I worried that I might be experiencing tinnitus —that is, ringing in the ears, perhaps evidence of hearing damage caused by my excessively loud saxophone playing. Medics define tinnitus as perceiving sound when there is no external source. For 5 to 15 percent of the population tinnitus is constant, and for 1 to 3 percent of people it leads to sleepless nights, impaired performance at tasks, and distress.
Theories of tinnitus abound, but most experts agree that it is caused by some sort of neural reorganization triggered by diminished input from outside sounds. Hair cells within the inner ear turn vibrations into electrical signals, which then travel up the auditory nerve into the brain, but this is not a one-way street; electrical pulses flow in both directions, with the brain sending signals back down to change how the inner ear responds.
In a silent place, or when hearing is damaged, auditory neurons in the brain stem increase the amplification of the signals from the auditory nerve to compensate for the lack of external sound. As an unwanted side effect, spontaneous activity in the auditory nerve fibers increases, leading to neural noise, which is perceived as a whistle, hiss, or hum. Maybe what I was hearing on the dunes was the idling noise of my brain while it searched in vain for sounds. A former colleague of mine, Stuart Bradley from Auckland University, has visited Antarctica, another place devoid of vegetation where silence can be heard.
Stuart is a tall New Zealander, sporting a fine mustache like a soccer player from the s. Ironically, what Stuart does in Antarctica is make noise and briefly ruin the pristine natural soundscape.
He uses a sodar a sound radar system to measure weather conditions, sending up strange chirps that bounce off of turbulent air in the atmosphere before returning to the ground to be measured.
No life apart from me. So no leaves either. No running water. No wind noise. I suspect this is because, although it was incredibly quiet, it was also a very, very open vista. The valley walls were 1,—2, meters high, and the visibility was amazing! My university has one of those anechoic chambers : an acoustically isolated room that provides unchanging, guaranteed silence, uninterrupted by wind, animals, or human noise.
It never fails to impress visitors, even though the entrance is utilitarian and uninspiring. Just outside the entrance they see dusty metal walkways, and nearby, builders are often making lots of noise constructing test walls in a neighboring sound laboratory. Guarding the anechoic chamber are heavy, gray, metal doors. You have to go through three doors to reach the chamber, because it is a room within a room.
To make the place silent, several sets of heavy walls insulate the innermost room, stopping outside noise from entering. The chamber is mounted on springs to prevent unwanted vibration from getting into the inner sanctum. Inside, the chamber is the size of a palatial office. First-time visitors are usually circumspect, not least because the wire floor is like a taut trampoline.
With the doors closed, they notice vast wedges of gray foam covering every surface, including the floor beneath the wire trampoline.
When showing visitors around, I like to say nothing at this point because it is fun to watch the realization sweep across their faces as they adjust to this unbelievably quiet space.
But it is not silent. Your body makes internal noises that the room cannot dampen. The foam wedges on the floor, ceiling, and walls absorb all speech; there are no acoustic reflections. With no sound from the outside world allowed in, the almost absolute silence will gradually manifest itself as an unbearable ringing in your ears. In the outside world, our ears are always exposed to some level of noise. But in the chamber, there is no air pressure at all on the ear drums, because there is no echo.
Very faint sounds become clearly audible because the ambient noise is exceptionally low. You can hear yourself breathing and it sounds somewhat loud. Sitting atop an array of vibration damping springs, the isolated chamber is enveloped by six layers of concrete and steel, which help to block out all sound from the outside world. Fiberglass wedges cover the floor, ceiling and walls, breaking up sound waves before they have a chance to reverberate back into the room.
Inside, the measured noise level is negative decibels — to be precise,
0コメント