You all know how the song goes:

   I'm a real guy, I like real guy things
   Like boats, and guns, and onion rings,
   But household chores need a power resolution.
   I went to the store and I purchased a solution...
   ...I got a pressure washer.
   I like it a lot
   Cos it makes cleaning DESTRUCTIVE!

Well, last night I went to a shop, and bought... an infrared remote 
thermometer, and an environment meter that measures light, sound and 
heat. Now I can find out the temparature of EVERYTHING!! Muhuhuhu!!!

Actually, the light readings are gibberish, and the temparature readings 
seem rather suspect. The sound readings seem reasonable though.

A number of people have complained about how loud of lab is. So I 
thought I'd find out how loud it *really* is!

Obviously, the first problem is trying to define "loud". According to 
the infallible Wikipedia, there are four standardised frequency responce 
curves commonly used. Apparently the "A" curve was designed for quiet 
sounds and is really rather invalid for loud sounds - and yet, almost 
all legal constructs operate on A-weighted readings. Ho hum! Apparently 
the "C" curve is a much better one to use.

In some unscientific experiments today, I've found that the readings 
from the metal really don't change very much depending on what I 
percieve the loudness to be. (OTOH, dB is a *logarithmic* scale...)

Depending on whether I select A-weighted or C-weighted filtering, I get 
a figure between 60 dB and 85 dB. Various Google searches indicate that 
long-term exposure to levels around 85 dB or higher result in hearing 
damage. (But infuriatingly NONE of the articles say WHICH WEIGHTING 
that's with, so it's kind of meaningless.)

At any rate, you can argue over different frequency response curves to 
use and what is or isn't harmful. But it seems that you can probably 
conclude that the noise levels in our lab are high enough to be of 
concern, even if you can't conclusively say they are or aren't safe.

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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