Whining Noctua P12?

Dee! · Post by **Dee!** » Mon Oct 13, 2008 8:35 am

I think my Noctua P12 is emitting a whining sound. Is this normal? It's a mid-range whine (a constant "ooooo" sound), not seriously loud but just enough to be annoying. One thing -- it's hooked up on the back of my Lian Li PC-V1010 case as an extraction fan. The case has an inbuilt 3-speed fan controller which I set it to mid speed most of the time, or low speed when I want a little more peace and quiet. Could the fan controller cause this? I swear the stock Lian Li fans were quieter on mid-speed, so now I'm wondering if I have a dodgy P12 on my hands. This is pretty annoying because as you all know the Noctua fans are expensive. I've had good luck with them in the past, but only used 80mm's.

ntavlas · Post by **ntavlas** » Mon Oct 13, 2008 9:56 am

I doubt that the fan controller is responsible for this.
Sometimes a nearby (especially in front of the fan) object can interact with a fan. I had a similar sound emmited by a fan that was normaly quiet. I had tomove it a couple of sentimeters for the sound to dissapear.

didi · Post by **didi** » Mon Oct 13, 2008 10:15 am

SPCR's review of the Noctua NH-U12P cooler talks about this particular fan.
http://www.silentpcreview.com/article850-page5.html At 9V the fan makes this particular noise, they compare it to an aircraft engine (bad comparison if you ask me, it's not nearly as loud

).
I've got that cooler, and yes, at certain speeds, the fan indeed makes a whining sound. Run the fan only a notch faster or slower and the whine disappears.
My guess it has to do with the notches in the fan blades. Really nothing wrong with the fan, the controller or any proximity to the fan.

walle · Post by **walle** » Mon Oct 13, 2008 10:39 am

didi wrote:I've got that cooler, and yes, at certain speeds, the fan indeed makes a whining sound. Run the fan only a notch faster or slower and the whine disappears.
My guess it has to do with the notches in the fan blades. Really nothing wrong with the fan, the controller or any proximity to the fan.

Excellent observation, after having tested this myself (though without reaching an accurate conclusion) (I own two of them) it seems to make perfect sense, would be nice if your findings /conclusion where to be included in the review.

Modo · Post by **Modo** » Mon Oct 13, 2008 1:31 pm

I doubt it's the notches. The NF-S12, which has no notches on the blades, shows the same symptoms. I believe the overall design, i.e. maximized measured airflow to fan speed (and thus measured noise) ratio, is causing this.

Dee! · Post by **Dee!** » Mon Oct 13, 2008 4:57 pm

Interesting stuff. Thanks for the replies. The only thing nearby is my CPU cooler, a Thermalright Ultima-90 with a Scythe 92mm fan on PWM mode. I might try moving the Noctua to another spot and see how it goes. Cheers again.

EDIT: It appears to be the fan's plastic housing. When I press my fingers on the back of the fan (where the Noctua sticker is) it stops the whining sound. I took the fan out of the case and have pretty much ruled out the possibility of anything in close proximity interfering with it because it still whines when free-standing or suspended in the air.

Not sure what to do now. It only happens at the speed I want to run it at, which is 1100 RPM. Typical! No problem with lower or higher RPM's.

didi · Post by **didi** » Tue Oct 14, 2008 11:22 am

In their review (link above) SPCR say they have the whining at 9V. This makes the fan run at 1060rpm (see voltage/noise/rpm table). That's only a very small difference to your 1100rpm. So it makes perfectly sense.
Why not run it at <1000rpm instead ? The loss in airflow is almost negligible and the fan will be much quieter.

Dee! · Post by **Dee!** » Tue Oct 14, 2008 2:21 pm

I can't run it at 1000, it's either 1100 or 900. I feel 900 is a little too slow. It's kind of like having a dog breathing on you! Too weak. This is an overclocked E8600 system @ 4.33GHz and silence isn't my main priority, I just want it quiet but still effective.

I have two low noise adapters that came with the fan. These knock the speed down by 200 RPM and 400RPM. I have a fan controller built into the case, and these do exactly the same thing. My only other option, if I want to run it closer to 1000 RPM, is to purchase a separate fan controller such as the Zalman Fan Mate.

I guess I'm stuck with this fan now if the whining is "normal" behaviour. I'm quite shocked, actually. I wouldn't expect something like this from such an expensive fan.

jaganath · Post by **jaganath** » Tue Oct 14, 2008 3:36 pm

I guess I'm stuck with this fan now if the whining is "normal" behaviour. I'm quite shocked, actually. I wouldn't expect something like this from such an expensive fan.

just because something is expensive, don't assume that automatically = quality. I could charge you Â£500 for dog cr@p, but that doesn't make it any better. as always, caveat emptor and all that.

didi · Post by **didi** » Wed Oct 15, 2008 10:32 am

Saying the fan is lacking quality would not be fair. It's very well constructed and fairly quiet ... at lower speeds and away from the whinging frequency range.

Dee! · Post by **Dee!** » Wed Oct 15, 2008 7:47 pm

Yes, the quality is top-notch and apart from the sound @ 1100 I'm happy with how it performs. I've had several Noctua products and they've all been very good. Today I also spoke to a guy who owns a few of these fans and he says his work fine at all speeds, no whine. I assume there's a bad batch floating around or something. This could happen with any fan.

thejamppa · Post by **thejamppa** » Thu Oct 16, 2008 12:23 pm

The Noctua blade designs cause the howl at the cortain speeds or when in high pressuer situation like pushing / pulling air thru filter. This was talked earlier in SPCR. this how made me return 2 x 1200 rpm noctuas. I can say out of my 4 1200 noctuas and 800 RPM Noctua's have holwed in certain speeds.

In my P182 my back noctua holwed in certain speed, when I opened the door howl stopped. When door was closed it howled again. Now in different speed it might now howl when door was closed but then it might howl when door was open unless running very slow speeds.

Quality is high but if you're sensitive to high pitched noise in certain situation these fans may not be the best.

Big SturL · Post by **Big SturL** » Sat Oct 18, 2008 12:06 pm

I'm running the fan at 5V and it is inaudible.

yamahaSHO · Post by **yamahaSHO** » Sat Oct 18, 2008 9:54 pm

Both of mine make this noise.... It's annoying me to the point that I'm swapping them out for some SlipStreams.

At full speed, they were too loud.... Period. With both the LNA and ULNA, they sounded about the same in my NSK-2480. Since I leave my computer on all the time in the living room, I can hear them and it's finally annoyed me.

I'm rebuilding my P180B here this week and I'll order some extra SlipStreams to swap in.

The Noctua's definitely are not a fan I would recommend for a quiet application. There are FAR better choices and MUCH cheaper prices.

Koolpc · Post by **Koolpc** » Sat Nov 01, 2008 2:18 pm

yamahaSHO wrote:The Noctua's definitely are not a fan I would recommend for a quiet application. There are FAR better choices and MUCH cheaper prices.

Which ones?

yamahaSHO · Post by **yamahaSHO** » Sat Nov 01, 2008 8:38 pm

Koolpc wrote:
yamahaSHO wrote:The Noctua's definitely are not a fan I would recommend for a quiet application. There are FAR better choices and MUCH cheaper prices.
Which ones?

I've got the newest ones (P12)... I'm out of town, but when I get home, I've got some SlipStreams ready to go.