Wind Noise From Grills: Caused By Intake or Exhaust??

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xenithon
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Wind Noise From Grills: Caused By Intake or Exhaust??

Post by xenithon » Mon Jul 18, 2005 9:35 am

Just a quick question: the wind noise associated with stock chassis grills - is that from the intake fans or from exhaust fans (ie. wind blowing out of grill or being sucked in through the grill)?

I am looking into reducing fan speeds (either 5V/7V mod or fan controller) as I do not want to cut my chassis, and wondering which would be more effective to slow down.

Cheers,
X

Tephras
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Post by Tephras » Mon Jul 18, 2005 2:07 pm

Both, but mostly from exhaust.
Keep in mind that the fan grills negative impact on the airflow will be of more concern with a slow running fan.

publicENEMY
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Re: Wind Noise From Grills: Caused By Intake or Exhaust??

Post by publicENEMY » Fri Mar 23, 2012 6:42 pm

i also wondering the exact same thing

i use noctua 120 pf fan on my norco 120mm fan blade and was expecting truly silent operation. instead i heard a noticeable woosh sound. the fan grill is on the intake. by switching the grill to be on the outtake/exhaust, does the woosh sound reduce? if it only takes 5 minutes to swap, i would do it no problem. thing is it takes hours to do so.

from what i read, it seems that the grill is better to be at outtake/exhaust. but i need confirmation(like scientific facts).

thanks.

kuzzia
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Re: Wind Noise From Grills: Caused By Intake or Exhaust??

Post by kuzzia » Sat Mar 24, 2012 11:46 am

I have these experiences:

PSU with SlipStream 1200rpm undervolted to approx 4-500 rpm. It pulled air through air vents on the bottom of the NZXT H2. Really annoying noise which disappeared when I flipped over the PSU which would then take air in from inside the case, i.e. with no air restriction.

Same fan setup as above as exhaust in NZXT H2. I can easily feel that much heat is trapped by the honeycomb metal in the rear fan position.

ces
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Re:

Post by ces » Sat Mar 24, 2012 4:50 pm

Tephras wrote:Keep in mind that the fan grills negative impact on the airflow will be of more concern with a slow running fan.
With a slow running ran (low CFM) you may be concerned about losing CFM, but a grill will have less impact on CFM. The impact of the grill multiplies exponentially as the speed of the air increases. If all you have is a 300rpm fan giving a slight drift to the air, the fan grill is not likely to have much of an impact, if at all.

tanassi
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Re: Wind Noise From Grills: Caused By Intake or Exhaust??

Post by tanassi » Mon Mar 26, 2012 12:49 am

The worst is actually intake, at least when I tested. I creates some odd backdraft that you can really notice, even at lower voltage (3,5V) with all the elite fans.

I ended up not using a side in take but using the slot in the bottom of my case (Fractal 3000). That solved it.

NeilBlanchard
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Re: Wind Noise From Grills: Caused By Intake or Exhaust??

Post by NeilBlanchard » Mon Mar 26, 2012 5:58 pm

If the grill is too close to the intake side of the fan it will make a lot of noise.

Without grills, you can often slow the fan even more, and still get decent temperatures.

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