Noctua A14 resonance noise (~700rpm)

[SpittinFax]

I jinxed it. I've discovered my Noctua NF-A14 Chromax has a resonance issue, after saying that Noctua fans are great if you want to avoid intermittent noise issues.

Typically I get a high frequency hum around 700rpm (41% PWM) and I hear it briefly at other speeds too. The internet would suggest I'm not the only user with this A14 noise issue. Mine is a rear exhaust fan and I've tried every trick in the book to cure it, with the only working solution being to set a different fan speed. It seems like the motor itself is the source of the noise rather than the airflow.

The A14 is a pretty common fan, so does anyone else have this issue?

It's also worth mentioning that I have a Noctua P14S Redux that doesn't have any audible resonance issues. My Noctua NF-A9 92mm CPU fan and Be Quiet 120mm Silent Wings 3 PWM fans are also dead silent.

 

[tabascosauz]

Like any other fan, the resonance noise depends almost entirely on how and where your fan is mounted, so it's impossible to start extrapolating unless we have the exact same setup and case. I've not noticed anything specific at 700rpm for any of my 8 x A14s of various types.

The design of your case, how the fans are mounted in it, the material of your case, your case's feet, etc. I'll put the same fan say A12x25 in the NCASE, Cerb, TJ08 and Core p3 and it'll sound like 4 different fans. Out on the bench, the A12x15 on my Big Shuriken or the B9 on my L12 is noiseless - put it in the L5 and it's a different story.

For A14s you can experiment with rubber mounts and different screws. Loosening the screws a little (not so much that the fan starts wiggling or flopping around) can help. Pressed up against a case panel with tight screws doesn't help.

• When mounted as a case fan with screws, my A14 brown/Chromax/A14 iPPC-2000 all hum starting at 980rpm under the 280mm rad. SAV2 rubber grommet mounting is a little better but still around 1200rpm or so.
• Without the rad and just up against the case, the Chromax pair are okay up to 1250rpm or so. The iPPC just don't do so well after 1000rpm.
• When used on an open bench (laid on top of the C14S for example), all the way up to 1500rpm is dead silent for regular/Chromax/iPPC (barring the industrial's motor noise).
• Same with gasketed to a rad alone, A14s are good up to 1500rpm. BUT if attached with screws to the case on the other side of the rad, doesn't matter if there's a gasket, starts humming.

Other fans are definitely not immune. A9, A9x14, F12 (the worst), A8, R8, P12 redux. A12x25s were the biggest disappointment for me as case fans in this respect.

The only real exception are the couple 120mm Silent Wings 3 I have. They are dead quiet, probably something to do with the special corner design they have. Unfortunately, the SW3s are also nowhere near the amount of air I need to push.

Exhaust fans shouldn't usually be as loud though. If you haven't already, SAV2 grommets are worth picking up. Wouldn't hurt to pick up a second fan with a free return policy to see if it's just that specific fan you bought? I only see a Reddit thread and another crosspost by the same user about this 700rpm issue. As a low-speed exhaust fan, it should be dead silent if isolated properly with rubber.

 

[SpittinFax]

Like any other fan, the resonance noise depends almost entirely on how and where your fan is mounted, so it's impossible to start extrapolating unless we have the exact same setup and case. I've not noticed anything specific at 700rpm for any of my 8 x A14s of various types.

The design of your case, how the fans are mounted in it, the material of your case, your case's feet, etc. I'll put the same fan say A12x25 in the NCASE, Cerb, TJ08 and Core p3 and it'll sound like 4 different fans. Out on the bench, the A12x15 on my Big Shuriken or the B9 on my L12 is noiseless - put it in the L5 and it's a different story.

For A14s you can experiment with rubber mounts and different screws. Loosening the screws a little (not so much that the fan starts wiggling or flopping around) can help. Pressed up against a case panel with tight screws doesn't help.

• When mounted as a case fan with screws, my A14 brown/Chromax/A14 iPPC-2000 all hum starting at 980rpm under the 280mm rad. SAV2 rubber grommet mounting is a little better but still around 1200rpm or so.
• Without the rad and just up against the case, the Chromax pair are okay up to 1250rpm or so. The iPPC just don't do so well after 1000rpm.
• When used on an open bench (laid on top of the C14S for example), all the way up to 1500rpm is dead silent for regular/Chromax/iPPC (barring the industrial's motor noise).
• Same with gasketed to a rad alone, A14s are good up to 1500rpm. BUT if attached with screws to the case on the other side of the rad, doesn't matter if there's a gasket, starts humming.

Other fans are definitely not immune. A9, A9x14, F12 (the worst), A8, R8, P12 redux. A12x25s were the biggest disappointment for me as case fans in this respect.

The only real exception are the couple 120mm Silent Wings 3 I have. They are dead quiet, probably something to do with the special corner design they have. Unfortunately, the SW3s are also nowhere near the amount of air I need to push.

Exhaust fans shouldn't usually be as loud though. If you haven't already, SAV2 grommets are worth picking up. Wouldn't hurt to pick up a second fan with a free return policy to see if it's just that specific fan you bought? I only see a Reddit thread and another crosspost by the same user about this 700rpm issue. As a low-speed exhaust fan, it should be dead silent if isolated properly with rubber.

Okay, I will say it right now as clearly as I possibly can: Case is NOT a factor. I know this because the fan still clearly resonates outside the case. I even removed the Low Noise Adapter in case that was causing it, but no fix. No amount of grommeting or adding mesh to break up the airflow is gonna fix this. It's the motor itself.

Thanks for the info though.

Fuck it, looks like I'm gonna just have to replace it.

 

[HTC]

Okay, I will say it right now as clearly as I possibly can: Case is NOT a factor. I know this because the fan still clearly resonates outside the case. I even removed the Low Noise Adapter in case that was causing it, but no fix. No amount of grommeting or adding mesh to break up the airflow is gonna fix this. It's the motor itself.

Thanks for the info though.

Fuck it, looks like I'm gonna just have to replace it.

Noctua's costumer support is usually top notch: suggest you explain the situation to them and see what they say.

 

[sam_86314]

I jinxed it. I've discovered my Noctua NF-A14 Chromax has a resonance issue, after saying that Noctua fans are great if you want to avoid intermittent noise issues.

Typically I get a high frequency hum around 700rpm (41% PWM) and I hear it briefly at other speeds too. The internet would suggest I'm not the only user with this A14 noise issue. Mine is a rear exhaust fan and I've tried every trick in the book to cure it, with the only working solution being to set a different fan speed. It seems like the motor itself is the source of the noise rather than the airflow.

The A14 is a pretty common fan, so does anyone else have this issue?

It's also worth mentioning that I have a Noctua P14S Redux that doesn't have any audible resonance issues. My Noctua NF-A9 92mm CPU fan and Be Quiet 120mm Silent Wings 3 PWM fans are also dead silent.

I have also experienced this with my A14s. I think the only way to avoid it is to tune your fan curve accordingly.

 

[SpittinFax]

Noctua's costumer support is usually top notch: suggest you explain the situation to them and see what they say.

Yeah probably, I still have all original packaging and proof of purchase which makes such things easier. Apparently I purchased it 2 years 8 months ago.

Still I'm not against the idea of buying something else and swapping this into a secondary rig.

 

[tabascosauz]

Yeah probably, I still have all original packaging and proof of purchase which makes such things easier. Apparently I purchased it 2 years 8 months ago.

Still I'm not against the idea of buying something else and swapping this into a secondary rig.

Since it's just an exhaust fan, could you just get a Silent Wings 120 or 140? No need for pressure or a lot of airflow, and it doesn't get any better for noise and vibration isolation. tbh still using metal screws for Noctua or BQ fans is a travesty

 

[Batou1986]

A year or so ago I bought an A14 and an S12 for exhaust fans the A14 is just about as loud as any other 140mm fan of decent quality I was not very impressed for the $25 premium, the S12 is almost silent though its blade design seems to have very low static pressure.
In the future I think I will go with silent wings had a pair that came with my darkrock that where dead silent at all but the highest RPM's.

 

[SpittinFax]

Since it's just an exhaust fan, could you just get a Silent Wings 120 or 140? No need for pressure or a lot of airflow, and it doesn't get any better for noise and vibration isolation. tbh still using metal screws for Noctua or BQ fans is a travesty

Yeah there's a good deal at the moment for Silent Wings 3 140mm PWM fans (they top out at 1000rpm). They might move less air in a resistance application but it's hardly a problem for normal case airflow situations.

One thing I will criticize the Silent Wings 3 fans for is that they make the slightest rattle sound on startup and very abrupt changes in speed. But their strength is being dead silent at low speeds and civilized at high speeds. When running at speed with a typical ramp up/down delays, I don't even notice them despite within one foot of my ear.

A year or so ago I bought an A14 and an S12 for exhaust fans the A14 is just about as loud as any other 140mm fan of decent quality I was not very impressed for the $25 premium, the S12 is almost silent though its blade design seems to have very low static pressure.
In the future I think I will go with silent wings had a pair that came with my darkrock that where dead silent at all but the highest RPM's.

It does seem like now that I'm playing with fan curves, I'm noticing the A14 is a louder fan than I thought it was. Considering that my 140mm NF-A14 is just as loud at the same RPM as my 2 x 120mm Silent Wings 3 fans, which are also positioned closer to my ears than the Noctua. Obviously every fan in existence is audible at some point but certainly it seems like the A14 is underwhelming.

At this stage I haven't had issues with my NF-A4 (running at 2000rpm dead silent) and NF-A9 at 1000rpm, so no idea why there's something wrong with the A14 in particular.

 

[tabascosauz]

Yeah there's a good deal at the moment for Silent Wings 3 140mm PWM fans (they top out at 1000rpm). They might move less air in a resistance application but it's hardly a problem for normal case airflow situations.

One thing I will criticize the Silent Wings 3 fans for is that they make the slightest rattle sound on startup and very abrupt changes in speed. But their strength is being dead silent at low speeds and civilized at high speeds. When running at speed with a typical ramp up/down delays, I don't even notice them despite within one foot of my ear.

It does seem like now that I'm playing with fan curves, I'm noticing the A14 is a louder fan than I thought it was. Considering that my 140mm NF-A14 is just as loud at the same RPM as my 2 x 120mm Silent Wings 3 fans, which are also positioned closer to my ears than the Noctua. Obviously every fan in existence is audible at some point but certainly it seems like the A14 is underwhelming.

At this stage I haven't had issues with my NF-A4 (running at 2000rpm dead silent) and NF-A9 at 1000rpm, so no idea why there's something wrong with the A14 in particular.

Your ears are impressively sensitive! I have 3 Silent Wings 120s and I honestly have a hard time even hearing them at any speed. Though they are quiet enough I can just set them at a static speed without any curve.

The A14 is a rather old fan with old blades and an old motor. It's next in line in the roadmap to be replaced by a newer model. The industrial A14s are durable and unique (albeit cacophonous), but the brown and Chromax A14 aren't very special.

 

[claes]

I had a similar experience to OP with a few samples. IMO it’s one of the only duds in their line-up, though better than a lot of other 140mm fans.

Here’s an acoustic analysis FWIW:

First 140 mm Fan Roundup: Noctua, Phanteks, Xigmatek

140 mm fans from Noctua, Phanteks, and Xigmatek battle in our latest fan roundup with one emerging as a clear winner in both thermal performance and acoustics. May 21, 2013 by Lawrence Lee Last month we staged an epic shoot-out among some popular 120 mm fans. Some great sounding fans emerged but...

silentpcreview.com

 

[HTC]

Yeah probably, I still have all original packaging and proof of purchase which makes such things easier. Apparently I purchased it 2 years 8 months ago.

Still I'm not against the idea of buying something else and swapping this into a secondary rig.

IIRC, they have a 6 year warranty: @ least with CPU coolers that's the case.

 

[qubit]

@SpittinFax Sounds like the fan is faulty. Noctua have a reputation for excellent customer support, so report the problem to them and I'm sure they'll replace it with a new fan.

 

[GerKNG]

i had a lot of noctua coolers over the years (3x NH D15, 3x NH U12S, 1x NH U14S and one very old NH D14)
almost all fans had some kind of resonance noise at a certain RPM range.
the 120mm Fans on the NH U12S for example have it in the 1200-1250RPM range, NH D15 Fans at around 1300RPM.
the only fans so far that are literally perfect are the NF A12x25 (have 4 of them)


700RPM is VERY low and barely moving air.
why not just use it at 900-1100 RPM? they are barely audible.

 

[freeagent]

Indeed, the fans on my D14 were not quiet at all. They were clearly audible throughout their operational range.

They weren't terribly loud, but you could hear them for sure.

 

[SpittinFax]

Your ears are impressively sensitive! I have 3 Silent Wings 120s and I honestly have a hard time even hearing them at any speed. Though they are quiet enough I can just set them at a static speed without any curve.

The A14 is a rather old fan with old blades and an old motor. It's next in line in the roadmap to be replaced by a newer model. The industrial A14s are durable and unique (albeit cacophonous), but the brown and Chromax A14 aren't very special.

Thanks, I wonder if it's a low noise floor that makes them sound louder. I did some testing with my smartphone to see what the decibel meter says and these were the numbers I got:

• All system fans at 300rpm = 25dB (what I would consider to be dead silent)
• Noctua A14 at 700rpm = 32.5dB (resonating)
• Noctua A14 at 750rpm = 30dB
• Silent Wings 3 (x2) at 1000rpm = 29.5dB

I'm sure that measuring with a smartphone isn't very accurate but comparing the numbers definitely seems to support what I've noticed audibly. And I think from memory every +5dB is a doubling of the sound pressure level. Seems like a combination of a low noise floor and the A14 being particularly loud.

i had a lot of noctua coolers over the years (3x NH D15, 3x NH U12S, 1x NH U14S and one very old NH D14)
almost all fans had some kind of resonance noise at a certain RPM range.
the 120mm Fans on the NH U12S for example have it in the 1200-1250RPM range, NH D15 Fans at around 1300RPM.
the only fans so far that are literally perfect are the NF A12x25 (have 4 of them)


700RPM is VERY low and barely moving air.
why not just use it at 900-1100 RPM? they are barely audible.

Yeah good to know, I am considering an upgrade to the Noctua U14S which uses the same A15 fans as the D15. Sounds like they give less trouble.

 

[qubit]

Indeed, the fans on my D14 were not quiet at all. They were clearly audible throughout their operational range.

They weren't terribly loud, but you could hear them for sure.

I'm surprised at this. Mine have been working very quietly since I installed the cooler in 2011 and work as well today as they did then, no squeaks or rattles, which is nothing short of amazing. I've had them connected with the speed reduction resistors this whole time in an open case right next to me where they make a quiet whisper, rather soothing actually. In fact, the single fan in my PSU is louder - it doesn't switch off.