Noctua fans in pull make a whirring/humming noise

[MonsterKiller]

Hello.

 

I have just gotten into water cooling and have purchased my first set of custom parts. I have a triple and single 140mm rad to use, for cooling CPU and GPU. When picking fans, the best recommended fans were Noctua ones, so I also purchase some NF-A14 FLX fans (with their hefty price tag). I wanted to use these in pull for 2 reasons, to hide their ugliness and to make the rad easier to clean. However, after putting the fans on the rad I noticed they made a bit of an annoying whirring/humming sound, but didn't when in push.

 

Audio recording of push: https://dl.dropboxusercontent.com/u/8117884/noctua-push.wav

Audio recording of pull: https://dl.dropboxusercontent.com/u/8117884/noctua-pull.wav

 

When listening to those, you can hear the noise in pull. However, the noise is a bit louder in person.

I tried using the low-noise adapter that comes with the fans, this reduced the noise but it was still slightly audible.

 

Is this normal?

[Artem]

It's not the fan, its the air turbulence. Whatever is in front of the fan is too restrictive. If you pull you rad out and try again in pull, I guarantee you wont hear that anymore.

[Artem]

Could be turbulance. Pretty common in situations where a fans intake path is restricted.

damn it lol

[MonsterKiller]

Could be turbulance. Pretty common in situations where a fans intake path is restricted.

 

 

It's not the fan, its the air turbulence. Whatever is in front of the fan is too restrictive. If you pull you rad out and try again in pull, I guarantee you wont hear that anymore.

 

 

I tested it on my desk, both sides were unrestricted (except for the rad ofc)

[Dragonzeanse]

I tested it on my desk, both sides were unrestricted (except for the rad ofc)

The radiator is causing the restriction. Your fans aren't generating enough static pressure to push air through its fins.

[MonsterKiller]

Not sure what you mean. But if the fan isnt making the noise in push but does in pull, then its turbulence causing the issue

 

Here's a picture oh how I did it.

 

Is there anything I could do to help the situation?

[TheProfosist]

I believe the flx models are the slower models that also come with the fand speed adapters. I would have gotten the pwm model. How thick is the rad? The reason I asked it because ive used a14 pwms on a h110 without any trouble at all.

[Dragonzeanse]

Here's a picture oh how I did it.

Is there anything I could do to help the situation?

Well, the air has to travel through a case, and possibly filtered intake, then through the radiator in order to cool components. That doesn't look like a particularly fin-dense radiator though; probably only about 7-10 fins per inch. That is a really bulky-looking radiator, though, so the fans need some good static pressure to travel through. What I find weird is that you're having issues with turbulence when you're not using the low-noise adapters, assuming that's the source of the noise and not just the fans speeding up.

[MonsterKiller]

I believe the flx models are the slower models that also come with the fand speed adapters. I would have gotten the pwm model. How thick is the rad? The reason I asked it because ive used a14 pwms on a h110 without any trouble at all.

 

Its a 60mm rad. I got the FLX ones over PWN because i was going to control them with a fan controller, which i cant plug 4 pins into and wont take advantage of PWM anyway.

[MonsterKiller]

Well, the air has to travel through a case, and possibly filtered intake, then through the radiator in order to cool components. That doesn't look like a particularly fin-dense radiator though; probably only about 7-10 fins per inch. That is a really bulky-looking radiator, though, so the fans need some good static pressure to travel through. What I find weird is that you're having issues with turbulence when you're not using the low-noise adapters, assuming that's the source of the noise and not just the fans speeding up.

 

7 per inch. I thought these Noctuas, being all "premium" and rad optimised, it wouldnt have had any problems

[Dragonzeanse]

7 per inch. I thought these Noctuas, being all "premium" and rad optimised, it wouldnt have had any problems

Like @TheProfosist said, I would have bought the PWMs. I would have just recommended you get different fans like Gelid Solutions WING 12s or Scythe Gentle Typhoons. If you can still return your Noctua fans, I would.

[MonsterKiller]

Quick update. I just tried the fans in push/pull on the rad but that just seemed to make the noise worse. The rad is a Phobya G-Changer 420mm V1.2 is that helps at all.

[TheProfosist]

7 per inch. I thought these Noctuas, being all "premium" and rad optimised, it wouldnt have had any problems

The a14's are not rad optimized the f12's are. Noctua doesnt have a 140mm fan thats rad optimzed (static pressure) yet, actually not many companies do and I cant think of one off the top of my head. I would have probably gotten push pull for a rad that thick. Also the pwm a14's are a whole 300rpm fastee but since their the same fan have the same specs at 1200rpm.

[TheProfosist]

Like @TheProfosist said, I would have bought the PWMs. I would have just recommended you get different fans like Gelid Solutions WING 12s or Scythe Gentle Typhoons. If you can still return your Noctua fans, I would.

Gentle typhoons dont come in 140mm and I assume that the 12 in the wing 12s means 120mm

[TheProfosist]

Quick update. I just tried the fans in push/pull on the rad but that just seemed to make the noise worse. The rad is a Phobya G-Changer 420mm V1.2 is that helps at all.

What speed are you running the fans at?

[MonsterKiller]

What speed are you running the fans at?

 

 I tried at full speed and with the low noise adapter.

[Dragonzeanse]

Gentle typhoons dont come in 140mm and I assume that the 12 in the wing 12s means 120mm

Right, 140mm. There are WING 14s from Gelid Solutions, but Scythe Gentle Typhoons don't exist in 140mm form factors. I'm not sure how well Phanteks fans work for radiators, but they're excellent as CPU cooling and case fans.

[TheProfosist]

I tried at full speed and with the low noise adapter.

Do you have other fan you could try even if their not 140mm and you just hold them up to the rad, this would tell you if its the rad causing it.

Also try holding the fan a bit away from the rad as this has been know to cut down on noise. You can get gaskets if this does work.

[MonsterKiller]

Do you have other fan you could try even if their not 140mm and you just hold them up to the rad, this would tell you if its the rad causing it.

Also try holding the fan a bit away from the rad as this has been know to cut down on noise. You can get gaskets if this does work.

 

I tried a Corsair SP120 on it and it actually did a similar thing. There was a noticeable whirring/humming when pulling air through it,

[TheProfosist]

I tried a Corsair SP120 on it and it actually did a similar thing.

Then its the rad causing it not the fans. did you try spacing the fans a couple mm off the rad? it might be intended to be used with a gasket.

[MonsterKiller]

Then its the rad causing it not the fans. did you try spacing the fans a couple mm off the rad? it might be intended to be used with a gasket.

 

It did come with gaskets but they didnt help.

 

I also read (whether this is actually true or not) that it could be because of the low FPI count?

[TheProfosist]

It did come with gaskets but they didnt help.

I also read (whether this is actually true or not) that it could be because of the low FPI count?

How thick is the gasket?

Could be? The lower the fin count the lower the pressue needed from the fans. Have you searched to see if anyone else had this issue on the rad?

[MonsterKiller]

How thick is the gasket?

Could be? The lower the fin count the lower the pressue needed from the fans. Have you searched to see if anyone else had this issue on the rad?

 

 

I cant see anything else.

 

I might see if I can get a different 420 or a 360 and use my SP120  fans on it.

[B NEGATIVE]

Use a 5-10mm shroud to lift the fan away from the rad,this will cure the whirring noise....

 

I really dont know why Noctuas are recommended for Rads...they are crap.

[TheProfosist]

I cant see anything else.

 

I might see if I can get a different 420 or a 360 and use my SP120  fans on it.

yea see if you can return it I think its just that rad since all different fans are doing it. Also a good alternative to corsair fans are the bitfenix ones. I personally dont like and cant recommend the corsair ones.