# What Fan Db Value Is Quiet ?



## jancz3rt

Hey I have a question regarding the noise that case fans and other fans make. The manufacturers say that 28DB is quiet. However I heard that 24 is what could be considered quiet. What do you guys know about that? I need to know cause my old fans are NOISY!!!. I mean it sounds like a tornado!

JAN


----------



## imjacktoo

Check this out.....

http://www.sidewindercomputers.com/tecar.html


----------



## Lorand

Nice music...  
Usually the noise level of a fan is proportional to its airflow. So Quiet = Ineffective.


----------



## kof2000

wow wee, mines sounds like a JET ENGINE


----------



## imjacktoo

It also depends on how the air is flowing,, check it out...

http://www.longwin.com/taf.htm


----------



## Praetor

A couple approaches to "quiet fans"
1. Outfit your computer with stealth fans, typically stealth is accepted as 27db or less (which includes most "stock" fans) or 24db or less (which only encompasses special "stealth" fans)

2. Get a fan controller. This way you _can_ get uber-loud fans which can help to evacuate air from the case real fast when you need it (i.e., movie encoding, video games etc) but tone it down to stealth-levels when you dont need it  The best of both worlds


----------



## jancz3rt

*Thanx a lot!*

I wanna thank all of you for providing me with a guideline with regards to the Db values. Thanks. I think my PSU fans both make like 40Db of noise. It's awful! Anyway I love the link with fan noises audio files.

JAN


----------



## Praetor

Glad to help


----------



## jancz3rt

*Yeah...thanx again.*

I just wanted to add that I replaced my noisy fans with 23db ones and believe me they are quiet! The only thing left that makes some noise is my CPU cooler. It runs at 4200rpm and has a 40mm fan! It makes over 30db of noise yet keeps my cpu temp below 40Celsisus .

JAN


----------



## DUK

*-oo-*

quietpc.com also makes quiet fans. More air flow does NOT always mean more loud... You can have a small fan spinning at 3000 rpm, an a large (120mm) fan spinnin at 900 rpm olny to find that they both pump the same volume of air and the large is completely un-noticeable. 
I have an athlon 1.4 with a 120mm fan spinning at 1000 rpm and you can sleep like a baby during the night with the PC left on if you want to... 
Controllers are nice as somebody said. You can tweak the fans during the day, and 'stealth' them during the night... 
The noise (in db) depends on the position of the fan also. Be warned, that if you have two fans that make 25db each, you will not get double the noise, nor still 25db. It is a logarithmig scale and you have to make some sums if you want to put everything right...


----------



## Praetor

> More air flow does NOT always mean more loud... You can have a small fan spinning at 3000 rpm, an a large (120mm) fan spinnin at 900 rpm olny to find that they both pump the same volume of air and the large is completely un-noticeable.


Yes but within a same size-class its a fair statement to say "the more airflow the greater the noise" 



> It is a logarithmig scale and you have to make some sums if you want to put everything right


Is it still O(log n) when you include crossblowers and vortex fans?


----------

