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how much noise???

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Nov 13, 2002
cheshire, uk
Does anyone know anything about acoustics??

I mean, how much noise will 2 '40dba' fans make when running together? Is it 80dba, 40dba or somewhere in between.:eh?:


AMD Athlon 2000+XP (Akasa AK-785CU H/S+fan 35dba)
Coolermaster SAF-S82(Exhaust, rear)
MSI KT4 Ultra SR
Geeforce2 MX440
256 PC333
40G 7200rpm
8G 5400rpm
Liteon writer
Budget ATX case with 400W P/Supply
Windows XP Pro
Temp's = Load 57 C(cpu) 41C(case)
Idle 53 C(cpu) 38C(case)


Senior Member
May 10, 2002
Los Alamos, NM
43 dBA

dB are a log function of the power so 40dBA + 40dBA is really a doubleing of the power. I believe there is a short write up on the OverClockers front page within the benchmarks or beginners guides there.

The human ear can generally detect a 1 dB increase and a 3 dB increase is clearly heard by most. A 3 dB increase would not knock your socks off but you'll know it happened if you listen to one and then the increase. :cool:
Last edited:


Aug 20, 2002
I thought that an increase of one decible, meant that the noise was doubled? So, if you had two fans rated at 25dB, they'd have a combined noise output of 26dB. Is this wrong? Is there something more that has to be done to find out the true decible output?