[SOLVED] Noctua NH-D15 annoying sound

[kapula747]

I bought an Noctua NH-D15 cpu fan a month ago and it has performed very well.

But I've noticed that when both fans are spinning, it creates some kind of soft long-toned vibrating sound. The sound is very annoying. I've reseated the heatsink, reinstalled the fans, tried 2 different motherboards, done the screws tighter, but with no success. The sound is still there. But what's strange is that it only occurs when both of the fans are spinning, f.e. when I stop one of the fans the sounds stops. So my guess is that it's not a problem with the fans in particular. And I can't accept the fact that it should be this way because it's pretty darn annoying in my opinion.

I've got an Silverstone Primera PM01-RGB case.

You can hear the sound in the linked youtube video.

[video="https://www.youtube.com/watch?v=HaRTpkbCBHs&feature=youtu.be"][/video]

 

[Lutfij]

FYI, don't touch the fans like you've shown in the video as they can damage the blades and possibly damage the fans header.

On another note, what you're experiencing is known as resonance. This is happening because at high RPM's they air draft is hitting the next fan array and producing the acoustic resonance you're seeing. My question is what are your full system's specs? Compared to the rear exhaust fan, you're CPU cooler's fans are running, to me, at full blast.

 

[kapula747]

FYI, don't touch the fans like you've shown in the video as they can damage the blades and possibly damage the fans header.

On another note, what you're experiencing is known as resonance. This is happening because at high RPM's they air draft is hitting the next fan array and producing the acoustic resonance you're seeing. My question is what are your full system's specs? Compared to the rear exhaust fan, you're CPU cooler's fans are running, to me, at full blast.

Oh, I did not know that it actually can damage the fans when I force stop them like that.

Full specs:
CPU: I7-4790K
Cooler: Noctua NH-D15
GPU: GTX 1080 Strix
MOBO: Asus Z97-pro gamer
Ram: 16gb kingston dd3 ram
Fans: 3x140mm Silverstone fans as intake, 1x140mm Noctua fan as outtake.
Case: Silverstone Primera PM01-RGB case.

I should have mentioned it earlier but I had the rest of the case fans running on Standard mode so that I could show/record the sound of the CPU fan when on 100% speed. The acoustic sound also occurs when the cpu fans are running on lower RPMs. Is there any solution for this? Should I move the fans up/down or something?