# Is 27dB-A loud or silent? Also is 32.4 CFM good?



## ADE

Is it like a like hum? What can I compare 27dB-A to? And is 32.4 CFM good?


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## magicman

I take it you're refering to a fan you're looking to buy or something. 27dB is audible but not intrusive, depending on where in your pc we're talking. 32.4 CFM is high for a 80mm fan but low for a 120mm fan. It's hard to accurately describe, without becoming subjective.


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## ADE

Its going to be an 80mm fan. and so the noise level will be hard to hear or easily noticeable?


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## magicman

Again, it's hard to say, as everybody's ability to hear it different, especially depending on how much loud music you listen to etc. But I would say you'll be able to hear it if you tune into it, but you'd most likely become habituated (accustomed) to it very quickly. It'll be less noticable if it's under a desk or something, or if there's other noise from either the pc (power supply often being the biggest) or something else in the room, but 80mm fans are conventionally more noticable than their 120mm alternatives. That's why people are opting for those where possible, and people are even buying mounts to convert a space for a 80mm fan into one for a 120mm fan.


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## ADE

cool. Its hard to here the standard 36 dB-A anyway. And they don't even get good CFM. Cool. Thanks for the info.


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## meanman

humans can here anything from 20db upwards


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## ADE

in what conditions?


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## Geoff

meanman said:


> humans can here anything from 20db upwards



Which is complete bs, the human threshold is 0dB.  10dB is a human breathing at 10 feet.

As for the original question, 27dB is on the loud side, and may become annoying.  I would look for something under 25dB (<20dB if possible), if you want a quiet PC.


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## r3dh3adkid

194 	-Theoretical limit for a sound wave at 1 atmosphere environmental pressure; pressure waves with a greater intensity behave as shock waves.
180 	-Krakatoa volcano explosion at 1 mile in air [1]
160 	-M1 Garand being fired at 1 meter (3 ft)
150 	-Jet engine at 30 m (100 ft)
140 	-Low Caliber Rifle being fired at 1m (3 ft); the engine of a Formula One car at 1 meter (3 ft)
130 	-Threshold of pain; civil defense siren at 100 ft (30 m)
120 	-Train horn at 1 m (3 ft). Perforation of eardrums.
110 	-Football stadium during kickoff at 50 yard line; chainsaw at 1 m (3 ft)
100 	-Jackhammer at 2 m (7 ft); inside discothèque
90 	-Loud factory, heavy truck at 1 m (3 ft)
80 	-Vacuum cleaner at 1 m (3 ft), curbside of busy street, PLVI of City
70 	-Busy traffic at 5 m (16 ft)
60 	-Office or restaurant inside
50 	-Quiet restaurant inside
40 	-Residential area at night
30 	-Theatre, no talking
20 	-Whispering
10 	-Human breathing at 3 m (10 ft)
0 	-Threshold of human hearing (with healthy ears); sound of a mosquito flying 3 m (10 ft) away

(Oh how i love wikipedia)


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## magicman

r3dh3adkid said:


> 180 	-Krakatoa volcano explosion at 1 mile in air


I'd really like to know who they got to measure a mile, then stand there with a decibel meter while an erruption was happening...


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