Sound or no sound creates industries
 

Our hearing is a subjective measure of sound; or is it an objective measure of sound level? I think it is loud. No, I disagree; it is not as loud as I thought. When a Plant Manager said it is not loud enough to wear hearing protection ear-plugs, he may well be cited by OSHA for violations. Both way, we pay money to create and we pay to eliminate, sound. Let´s take a look at how much noise FANs inside a PC make.

http://www.madshrimps.be/gotoartik.php?articID=268

Should have done this earlier. Let you judge what is silent, quiet or dead silence relative to dBA numbers you have read.
Base level of my room noise is 37.2 to 37.8 dBA.