[plug] Hot and bothered CPU hankers for cool breeze

James Devenish devenish at guild.uwa.edu.au
Tue Dec 16 21:50:21 WST 2003


In message <20031216124328.GA8482 at erdos.home>
on Tue, Dec 16, 2003 at 08:43:28PM +0800, Cameron Patrick wrote:
> On Tue, Dec 16, 2003 at 08:40:54PM +0800, Derek Fountain wrote:
> | I'm intrigued! Why do 400 boxes not sound 400 times louder than 1 box?
> My understanding is that a 10dB increase corresponds to ~2x louder,

Hmm...are we talking about intesity or power? In the case of intensity,
~3dB corresponds to 2x more intense and 10dB corresponds to 10x more
intense. (Power presumably involves the square of intensity, so it would
be typical to calculate 20log(f(P)), as opposed to 10log(f(I)).) Of
course, talking about power might be more practical since it relates
readily to energy. But I think "louder" would be a perceptual
phenomenon and we'd have to ask the audiologists.

In message <20031216124752.GD7965 at erdos.home>
on Tue, Dec 16, 2003 at 08:47:52PM +0800, Cameron Patrick wrote:
> And from this we deduce that either I don't have a clue what I'm talking
> about, or James slept through his Physics classes :-)

I'm not sure that the 'semantics' of aural decibels are well defined for
anything other than 0dB. That is, I have no intuitive reason to think
that we can relate increases in intensity or power to perceptions of
noise in a proportional fashion.





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