[OT] Decibels and the ear [was: Re: [plug] Hot and bothered CPU hankers for cool breeze]

[James Devenish]

In message <Pine.LNX.4.58.0312171452310.28723 at ob.golden.wattle.id.au>
on Wed, Dec 17, 2003 at 03:00:58PM +0800, Mike Holland wrote:
> On Wed, 17 Dec 2003, James Devenish wrote:
> > > lost. 400 fans are 400x louder.
> >
> > Well no. This is what I was saying (but I didn't realise Cameron had
> > beat me to it). 400 fans produce 400 times the noise. But whether that
> > is 400x *louder* is a consequence of our physiology (or physio-
> 
> I'm not sure I agree. If you want to know when two notes of different
> pitch are the same loudness, thats physiology. But what does it mean to
> say one noise is twice as loud as another?

As far as I know, "loudness" is "measured" my asking people about their
perceptions. "Is that too loud?" "Is it loud enough?" "Is that as loud
as the the other one?" "Does it hurt when I do this?" :)

> If you asked to turn the volume knob "twice as loud", would people act
> consistently?

Apparently that is what people study at University :)

> The only sensible interpretation of "n times as loud" I can think of, is
> to say it "sounds as if there are n times as many sources". The problem
> is, we rarely have the chance to hear such comparisons, and judgement is poor.

Right, but it is the only sensible interpretation. "Too loud", "not loud
enough" and "didn't notice the difference" are perceptual. Aren't they?