PC Resonating

I had this on a cheap Coolermaster Elite 331 case. It resonated badly but because it didn't have many moving parts you could find what was causing the noise. It's most likely anything that can rattle or be loose that will cause the noise. Unless all the fans are operating at the case's natural frequency. It's odd as Fractal cases are quite nicely made, wouldn't have thought you'd get that off a solid case.
 
Relentless81 said:
Really? That's going to make a hell of a lot of hot air just sat in the case, I could try it to see if it makes the noise go away though
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Hot air cannot 'set in the case'. Think of case ntake and exhaust fans as push/pull fans on a cooler. Cooler still works with jsut one and is usually on 1-2c warmer. ;) For air to flow it has to move both into and out of case. If no air leaves case, no air can come in.
 
Ok, ill disable the rear exhaust but have to be tomorrow, so far tonight I've ran it without the front filter and moved the PC away from its usual place but no dice, the noise is still there drilling into my mind
 
Relentless81 said:
Just did a quick test with exhaust fan disabled, noise is still there and cpu got hotter:(

Man this grim
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I feel for you. I've chased similar things and it is sometimes very hard to identify the source. I chased a intermittent hum in my hi-fi once for 6 months .. until I realized it was the refrigerator about 30 feet away and two room over. ;)

The possibilities for harmonic vibrations originate from vibrations generated by fan impeller imbalance and/or alignment .. and possibly by vibrations in fan blades when they are too close to a surface. Some fan & cooler companies have spacers for use on cooler fans when they are in pull orientation. This is because the impeller / blade is 3-5mm closer to mounting surface when mounted to pull than when mounted to push. There is also a slim chance the impeller is creating a low frequency sound that is causing case to resonate, but that is not likely the case. Physical vibration from imbalance or impeller alignment are most likely.

Bottom line, it almost has to be one of the fans, so systematically disabling and reconnecting them until you find the one (possibly more than one) that is causing the problem.
 
Think I might have sorted it in the last hour after another night of messing but its too weird to be sure, been gaming for the last hour and the noise is gone all I can hear now is normal fan noise.

The bottom intake fan causes it when it runs at high RPMs, all I can think of is the GPU is a millimetre away from it and it causes turbulence or something, disabled it and the sound went away but the system got really loud trying to compensate for the missing intake so I fitted a low noise adaptor to it and set it to silent in the BIOS and it seems to be working with the annoying noise not happening in the last hour. The fan itself is fine as the noise follows the location of the fan.

Really strange and could just be coincidence but hopefully its finally sorted if so I'll be made up
 
That sounds like a likely scenario.
But I have to ask how can the GPU only be 1mm away from the fan? Is fan mounted to PSU cover insead of bottom of case?
 
doyll said:
That sounds like a likely scenario.
But I have to ask how can the GPU only be 1mm away from the fan? Is fan mounted to PSU cover insead of bottom of case?
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I might have spoke too soon to be honest, think it started doing it again as soon as I submitted that post just not as loud and not under load so its like I've just changed the scenario that the noise occurs , need to confirm tonight was too tired last night.

its a Define C case with a Fury Nitro which is a long GPU. The clearance between the bottom front intake and the GPU is literally a millimetre or two

the PSU is at the back of the case under the a shroud
 
Have you mounted a fan directly above the PSU. Which way is your PSU mounted? From the pictures, it looks like the PSU could be mounted inverted. You should not need a fan in that position. Try removing the fan and inverting the PSU.
 
Quartz said:
Have you mounted a fan directly above the PSU. Which way is your PSU mounted? From the pictures, it looks like the PSU could be mounted inverted. You should not need a fan in that position. Try removing the fan and inverting the PSU.
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Not sure what you mean, PSU intakes from the bottom of the case and is fitted at the back of the case
 
Sorry, I misunderstood. I assumed when you said 'bottom intake' you were referring to on on bottom vent in Define C case. ;)

Maybe remove the case PSU cover and either move your 'bottom intake' lower down on the front or to vent in bottom of case. Or maybe remove case PSU cover, lower bottom front intake and add another intake in bottom vent.

Is it obvious I'm not a big fan (no pun) of full length case PSU covers? :p
 
I really like PSU covers for looks but if I could remove it to test I would, the fan wont go any lower because the 3.5 drive caddy is directly below it though

I've sorted the issue with a manual fan curve, the lower fan doesn't go over 50% which stops it from spinning up fast enough to cause too much air against the gpu and the noise but still enough to feed the GPU some fresh air, surprisingly its now completely silent at idle I can barely tell its on and under load its better too, temps seem the same if not 1 or 2 degrees better somehow
 
It might be also that PSU shroud which starts vibrating as it has big flat surface likely without mass damping.

Tiny case if there's barely room for standard length cards...:p
 
Could set something dense like a .. hockey puck or maybe a big magnet in middle of PSU cover and see if that stops it from resonating. Just don't get magnet less than 3" away from HDDs. :p
 
Fans in series only achieve directional flow, they don't actually increase the flow by much at all, so yes you can remove the extraction fan. Especially with two 140mm fans as intake you won't notice any difference in temps. Fans are a dark art. In general though positive pressure is a good thing so extraction fans are bad unless you are deliberately trying to force where the air exits. An absorption pad somewhere. Neoprene should do it. Can you place a neoprene pad on the floor of the case or on the side ( if not glass or acrylic )?
Also.. have you noticed that fans make more noise when an object is close to the vacuum side? Are you using the fans to push air through the radiator or to pull it through. You might like to try swapping it round, whichever you are using. Another way to reduce noise is to use a spacer between the fan and the radiator. An old fan with the motor blade assembly removed makes a great spacer.
 
Relentless81 said:
Turns out this was my desk all along, not sure how a desk can cause the noise but its definitely the desk
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Are there are metal panels on your desk? Because they can easily

Pocah said:
Fans in series only achieve directional flow, they don't actually increase the flow by much at all, so yes you can remove the extraction fan. Especially with two 140mm fans as intake you won't notice any difference in temps. Fans are a dark art. In general though positive pressure is a good thing so extraction fans are bad unless you are deliberately trying to force where the air exits. An absorption pad somewhere. Neoprene should do it. Can you place a neoprene pad on the floor of the case or on the side ( if not glass or acrylic )?
Also.. have you noticed that fans make more noise when an object is close to the vacuum side? Are you using the fans to push air through the radiator or to pull it through. You might like to try swapping it round, whichever you are using. Another way to reduce noise is to use a spacer between the fan and the radiator. An old fan with the motor blade assembly removed makes a great spacer.
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Stacking fan in series has on effect on directional flow, but their combined static pressure rating almost doubles if there is something (radiator) between them to straighten their airflow .. and almost doubling their static pressure mean if a single fan was struggling to overcome airflow resistance doubling the static pressure will dramatically increase the airflow.

If you are using the term "fans in series" for a case having intake and exhaust, then this kind of 'series' is can both increase case airflow and help channel the airflow from intake to cooler and on to exhaust fan, or from intake toward top of case. But the latter often draws GPU heated exhaust toward top where it mixes with and warm the cool intake air going to CPU cooler.

While what you are saying shows some knowledge you do not really understand how fan and case airflow application funtions. actually flow It seems you have just enough knowledge of fans and case airflow to think you know what you do not know. You really need to learn more about fans, the working of case airflow and optimization of case airflow before you start trying to tell others about it. Here is an old guide to airflow and optimizing case cooling / airflow.
https://forums.overclockers.co.uk/t...-i-put-my-temp-sensor.18564223/#post-26159770
You can read it or not, but if you do and have questions please start a thread and we can discuss it more.
 
doyll said:
Are there are metal panels on your desk? Because they can easily


Stacking fan in series has on effect on directional flow, but their combined static pressure rating almost doubles if there is something (radiator) between them to straighten their airflow .. and almost doubling their static pressure mean if a single fan was struggling to overcome airflow resistance doubling the static pressure will dramatically increase the airflow.

If you are using the term "fans in series" for a case having intake and exhaust, then this kind of 'series' is can both increase case airflow and help channel the airflow from intake to cooler and on to exhaust fan, or from intake toward top of case. But the latter often draws GPU heated exhaust toward top where it mixes with and warm the cool intake air going to CPU cooler.

While what you are saying shows some knowledge you do not really understand how fan and case airflow application funtions. actually flow It seems you have just enough knowledge of fans and case airflow to think you know what you do not know. You really need to learn more about fans, the working of case airflow and optimization of case airflow before you start trying to tell others about it. Here is an old guide to airflow and optimizing case cooling / airflow.
https://forums.overclockers.co.uk/t...-i-put-my-temp-sensor.18564223/#post-26159770
You can read it or not, but if you do and have questions please start a thread and we can discuss it more.
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Basically i made a simplified statement that I felt OP could remove the rear fan without any great detrimental affect on the system and you come back with that? Seriously? What is your problem?
You assume from that one statement that I know nothing about fans. I have a degree in physics and electronics. I have a excellent understanding of airflow, fans and thermodynamics and have spent many years in the electronics industry, and even many, many hours real world testing of fan setups for cooling PC's. Seriously, you should learn more about people before you start assuming what they do or do not know. But most importantly, why the incredible aggression? I find it utterly staggering that you would be so rude without really knowing who you are talking to, and without any real reason?
 
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