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Help choosing compression fan

qwertz
Level 9
Hi,
I have plans to mod pc so that in case only 2x 140mm compression fans that push air in and all holes in pc case closed , only air to pass trough cpu cooler.

It would be to achive maximal silence.

Gpu is the type that pushes heat out of case.


Should i look for bearing fans or some sort of soft anti vibration mounts to avoid noise transfer to case?

What fan is most silent and good for compression?
Will the forum bugs get fixed?
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15 REPLIES 15

davemon50
Level 11
qwertz wrote:
Hi,
...only 2x 140mm compression fans that push air in and all holes in pc case closed , only air to pass trough cpu cooler.

...Gpu is the type that pushes heat out of case.

...some sort of soft anti vibration mounts to avoid noise transfer to case?

What fan is most silent and good for compression?



I'm trying to get an idea of how you are configuring your system, but your first statement above has me worried for you. Do you happen to have a schematic of what you are trying to achieve?

You must have good case cooling for internal heat generation outside the CPU heat, especially if you don't have a liquid cooled GPU, so you can't close off the case, it needs to allow for either relief air or exhaust air, or both. Any case will have leakage, so you get relief air to some degree if the case is positively pressurized, but if you seal it without exhaust airflow you will stifle the intake fans' operation and they will ride their curves. When they ride their curves you get less airflow, and higher static and higher noise.

All fan manufacturers publish dBA for their fans, so for comparison look at their catalogued/tested max rpm and dBA, pick the best, and set your system to operate at their lowest possible rpm for the temperatures you are comfortable with.

Yes, on vibration mounts, because all fans transmit vibration to the case regardless of noise generated by blade tip speeds. Rubber.

A final initial thought is that there is a sound/noise benefit to more fans running a greater quantity of fans at lower rpm's for the same amount of cooling (lower rpm's of course meaning lower noise per fan). But be careful there too because more fans also generate more noise. For example, two fans running together at 38 dBA each actually generates more than 38dBA, it will be closer to 41 or 42 instead.

Perhaps you can share a schematic, or a little more on your configuration goals?
Davemon50

davemon50 wrote:
I'm trying to get an idea of how you are configuring your system, but your first statement above has me worried for you. Do you happen to have a schematic of what you are trying to achieve?

You must have good case cooling for internal heat generation outside the CPU heat, especially if you don't have a liquid cooled GPU, so you can't close off the case, it needs to allow for either relief air or exhaust air, or both. Any case will have leakage, so you get relief air to some degree if the case is positively pressurized, but if you seal it without exhaust airflow you will stifle the intake fans' operation and they will ride their curves. When they ride their curves you get less airflow, and higher static and higher noise.

All fan manufacturers publish dBA for their fans, so for comparison look at their catalogued/tested max rpm and dBA, pick the best, and set your system to operate at their lowest possible rpm for the temperatures you are comfortable with.

Yes, on vibration mounts, because all fans transmit vibration to the case regardless of noise generated by blade tip speeds. Rubber.

A final initial thought is that there is a sound/noise benefit to more fans running a greater quantity of fans at lower rpm's for the same amount of cooling (lower rpm's of course meaning lower noise per fan). But be careful there too because more fans also generate more noise. For example, two fans running together at 38 dBA each actually generates more than 38dBA, it will be closer to 41 or 42 instead.

Perhaps you can share a schematic, or a little more on your configuration goals?


Made the drawing to explain better.


Thanks for good answers.

Yesterday i closed all case holes/vents , but i am thinking about better compression fans and maybe should open some ports up to create more free airflow as i probably have stifled the intake fans' operation already. Lots of leak air comes out trough fan blade side area as it cannot pressurize all into case.

Measurable air only pass trough the watercooler and some pushes back trough fans, case is sealed quite well. Also i have noticed the pressure slightly lowered gpu temps.

Atm using corsair H110 280mm watercoolers default fans , but those are quite bad quality , vibrate alot of noise if tightly mounted on case and with years the bearings have got quite loose.

I dont know alot about pc fans but i am sure there are better fans for this purpose.

I see dBA stats but it would only be useful for comparing info if i know pressure/db or airflow/db graph.
Would be good if very well balanced fan , so less noise transfered/amplified by pc case. And good if it ball bearing or something that lasts.
Will the forum bugs get fixed?

davemon50 wrote:
I'm trying to get an idea of how you are configuring your system, but your first statement above has me worried for you. Do you happen to have a schematic of what you are trying to achieve?

You must have good case cooling for internal heat generation outside the CPU heat, especially if you don't have a liquid cooled GPU, so you can't close off the case, it needs to allow for either relief air or exhaust air, or both. Any case will have leakage, so you get relief air to some degree if the case is positively pressurized, but if you seal it without exhaust airflow you will stifle the intake fans' operation and they will ride their curves. When they ride their curves you get less airflow, and higher static and higher noise.

All fan manufacturers publish dBA for their fans, so for comparison look at their catalogued/tested max rpm and dBA, pick the best, and set your system to operate at their lowest possible rpm for the temperatures you are comfortable with.

Yes, on vibration mounts, because all fans transmit vibration to the case regardless of noise generated by blade tip speeds. Rubber.

A final initial thought is that there is a sound/noise benefit to more fans running a greater quantity of fans at lower rpm's for the same amount of cooling (lower rpm's of course meaning lower noise per fan). But be careful there too because more fans also generate more noise. For example, two fans running together at 38 dBA each actually generates more than 38dBA, it will be closer to 41 or 42 instead.

Perhaps you can share a schematic, or a little more on your configuration goals?


Made the drawing to explain better.


Thanks for good answers.

Yesterday i closed all case holes/vents , but i am thinking about better compression fans and maybe should open some ports up to create more free airflow as i probably have stifled the intake fans' operation already. Lots of leak air comes out trough fan blade side area as it cannot pressurize all into case.

Measurable air only pass trough the watercooler and some pushes back trough fans, case is sealed quite well. Also i have noticed the pressure slightly lowered gpu temps.

Atm using corsair H110 280mm watercoolers default fans , but those are quite bad quality , vibrate alot of noise if tightly mounted on case and with years of running cpu full load at nights the bearings have gotten quite loose and vibration/noise has gotten worse.

I dont know alot about pc fans but i am sure there are better fans for this purpose.

I see dBA stats but it would only be useful for comparing info if i know pressure/db or airflow/db graph.
Would be good if very well balanced fan , so less noise transfered/amplified by pc case. And good if it ball bearing or something that lasts.
Will the forum bugs get fixed?

qwertz
Level 9
The lower/bottom fan actually cant fit as PSU takes up too much space.
So could fit 2 compression fans on top of watercooler to take air faster trough cooler by having positive pressure on 1 side and negative on other
Will the forum bugs get fixed?

davemon50
Level 11
I modified your diagram slightly. If you don't already have it, try filtering your intake air for cleanliness of internal components. Not a sure thing but helps if you clean them regularly. If you plan to intake air at the bottom of the machine, that's the dirtiest air you will intake, so definitely filter that air.

Also, in the diagram you posted, you have 3 intake fans if you include the bottom intake. The third intake fan at the bottom is not a mistake (if filtered), but consider an exhaust fan if possible in the top rear of the machine as well or in lieu of. You mentioned in your last post that you couldn't fit the bottom intake fan in because of the PSU, so I would recommend the location shown in the adjusted schematic.

If you are getting vibration definitely get some rubber mounts to get the fan housings isolated from the computer casing.

Final thought: be very careful about changing out your H110i fans. If you choose to do this, know that those fans are designed for high static pressure in order to compensate for the radiator. You can use other fans there, but case fans are generally not high static fans so you won't get the same performance curve for those fans. Corsair designed those fans with the radiator in mind.
Davemon50

qwertz
Level 9
Yes those corsair ones 3.99 mm/h2o pressure, but bearings are not too good/reliable in my opinion ,

Would need help on choosing 4 similar quiet fans , 2 to compress air into case and 2 for top of radiator.

>Atm 2 candidates are corsair ML140 "featuring levitation" and noctua fans
Will the forum bugs get fixed?

qwertz wrote:
Yes those corsair ones 3.99 mm/h2o pressure, but bearings are not too good/reliable in my opinion ,

Would need help on choosing 4 similar quiet fans , 2 to compress air into case and 2 for top of radiator.

>Atm 2 candidates are corsair ML140 "featuring levitation" and noctua fans


Go and have a look at the Noctua site. They have rubber grommets for attachment which reduce vibration. They are very quiet.

S series are for static, F series for pressure and P for in between.

Also worth looking at their Industrial Fan series.

I won't confuse the issue by telling you about their new A series that aren't released yet!!!

qwertz
Level 9
I think that Noctua vs Corsair are about equal for quiet usage , corsair has higher rpm range and compression with more noise at top end but at similar speeds they seem to achive almost same results.
Will the forum bugs get fixed?

Korth
Level 14
Noctua's NF-A14 iPPC 3000 PWM fan is a truly magnificent beast. Note that it produces 41.3dB only at full 3000rpm, in practice it's virtually indistinguishable (in terms of noise output, airflow, and air pressure) from a NF-A14 iPPC 2000PWM fan when spinning ~2000rpm (aside from drawing more electrical power). Noctua's "Flow Acceleration Channels", "Advanced Acoustic Optimisation", "Stepped Inlet Design", and "Inner Surface Microstructures" - basically a bunch of calculated tiny notches and surface features and geometric twists and tweaks on each fan blade - actually do combine to reduce apparent (but not measured) noise output fairly significantly. (They essentially exploit "psychoacoustic perception" by shifting the noise towards audio frequencies where we have less sensitivity - and this trick works well on everyone, though better for some people than others.)

The IP52-sealed metal SSO2 bearing, high-precision minimum-tolerance construction, custom PWM IC, quality motors and magnets, silicone anti-vibration mounts, >150,000h lifespan (and 6-year warranty) are all just added gravy.

A downside on the NF iPPC fans is their plain appearance. But at least they're primarily black and have only hints of Noctua's trademark yucky brown/biege on the corner pads (and even these can be replaced if one finds them too offensive, lol). The other downside is high cost.

I'd be interested in any Corsair (or other brand) 12V PWM fan which can provide airflow of 269.3 m³/h (158.5 CFM) and static pressure of 10.52 mm/H₂O at (less than) 41.3dB(A).
"All opinions are not equal. Some are a very great deal more robust, sophisticated and well supported in logic and argument than others." - Douglas Adams

[/Korth]