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

[Cameron Patrick]

On Wed, Dec 17, 2003 at 02:05:57PM +0800, Derek Fountain wrote:
| > The "rule of thumb" (that Cameron provided) implies that
| > increasing the intensity 400-fold would cause a 2.6-fold increase in
| > loudness. Derek's experience would seem to indicate that 400 machines
| > were not 400 times louder than one machine.
| 
| Obviously in a lab that size a lot of the machines were some distance away 
| from any one point - someone standing in the middle of the room might be 
| barely able to hear a machine in the furthest corner, even when the room is 
| otherwise silent.

Hence what I mentioned about the inverse square law ;-)  Given the size
of the room and assuming that the computers were evenly distributed you
could get a decent approximation of what kind of noise level you'd
expect from the computers, if not everything else in the room.

| And since the room also contained several thousand high performance
| disks spining at full speed, not to mention the extraordinary air
| conditioning required to keep everything cool, getting a precise
| handle on how loud the servers were probably isn't possible.

Yeah, fair enough.

| The theories and algorthims put forward in this discussion were
| interesting, but for this example they probably get washed out by the,
| er, noise. :o)

*grin*  We should at least have explained why it didn't seem to be 400
times louder, even if we couldn't agree on how loud it really should be
or take into account any :-)  Anyway, glad you at least found it
interesting.

| Actually, it's discussions like this one which sometimes make me wish I'd 
| studied physics or chemistry or maths rather than CS. I wish I understood 
| more!

Me too (wish I understood more, that is)!  Although there's no excuse
for anyone not studying maths :-) even if our education system
(including universities) seem to do their damnedest to put people off
it...

Cameron.