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Can you "hear" absolute silence? - Page 6

post #76 of 78

 

Btw I read an article online once linking diet and obesity to tinnitus.

 

 

It said kids are getting more tinnitus these days, but they are also fatter.

post #77 of 78

Necro-bump...was looking up what folks here when they are alone and in a quiet place...I hear a very faint hissing noise myself.

 

An interesting note: John Cage the experimental composer was profoundly influenced by an experience he had in an anechoic chamber.

 

An anechoic chamber is meant to be the most soundproof environment you can get. He was fascinated by silence and so arranged to get a session in one to experience "true" silence. While in the chamber he heard a faint rushing noise and wondered what it was. The technician informed him that the experience was common. In absolute silence, we can never achieve absolute silence. The rushing noise he heard was the sound of his own blood pumping through his veins.

 

We will never be able to achieve true silence in the physical realm.

post #78 of 78
Quote:
Originally Posted by Aizura View Post

 

So tell me people, do you hear absolutely nothing when there's no outside noise? Or do you also always hear some faint noise coming from inside your head?


I haven't read the thread in its entirety, but I thought I'd add a little science to it. In 24/192 Music Downloads are Very Silly Indeed there is a section discussing dynamic range, 16 bit vs 24 bit, and absolute hearing thresholds. While it's relative to the human ears, there is such a thing as an absolute threshold of hearing (i.e. "absolute" silence), a sound level below which humans do not hear a thing. So there is such a thing as sounds you cannot hear.

 

"First, we measure the 'absolute threshold of hearing' across the entire audio range for a group of listeners. This gives us a curve representing the very quietest sound the human ear can perceive for any given frequency as measured in ideal circumstances on healthy ears. "

 


 

It's worth remembering that dB is a relative measure of sound intensity:

WordNet (r) 3.0 (2006) (wn)
Db
2: a logarithmic unit of sound intensity; 10 times the logarithm
of the ratio of the sound intensity to some reference
intensity [syn: decibel, dB]

 

 

The loudest sounds we can hear are really LOUD:

"Revisiting your ears

We've discussed the frequency range of the ear, but what about the dynamic range from the softest possible sound to the loudest possible sound?

One way to define absolute dynamic range would be to look again at the absolute threshold of hearing and threshold of pain curves. The distance between the highest point on the threshold of pain curve and the lowest point on the absolute threshold of hearing curve is about 140 decibels for a young, healthy listener. That wouldn't last long though; +130dB is loud enough to damage hearing permanently in seconds to minutes. For reference purposes, a jackhammer at one meter is only about 100-110dB."

 

And for the most interesting part for this thread:

"Environmental noise

Few people realize how quiet the absolute threshold of hearing really is.

The very quietest perceptible sound is about -8dbSPL [11]. Using an A-weighted scale, the hum from a 100 watt incandescent light bulb one meter away is about 10dBSPL, so about 18dB louder. The bulb will be much louder on a dimmer.

20dBSPL (or 28dB louder than the quietest audible sound) is often quoted for an empty broadcasting/recording studio or sound isolation room. This is the baseline for an exceptionally quiet environment, and one reason you've probably never noticed hearing a light bulb."

 

The human ear can actually hear sounds less loud than the humming of a light bulb... For reference:

"120dB is greater than the difference between a mosquito somewhere in the same room and a jackhammer a foot away.... or the difference between a deserted 'soundproof' room and a sound loud enough to cause hearing damage in seconds."

 

 

Testing yourself for absolute silence can be tricky unless you have access to some soundproof room. And even there you will be subject to environmental noise, your heart beating, stray mosquito's, working light bulbs and so on...

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