Weird fan problem driving me crazy, please help!

[imported_mlt]

So I finally got my new i7 system ready in a Coolermaster Silencio 550 case (which is great!). Picture: http://inc.kuvat.fi/kuvat/i7silencio/silencio01.jpg

I soon noticed that the original 120mm fans on the case make a annoying clicking sound. This was also mentioned in some reviews of the case.

So I replaced the fans with couple of Scythe slipstream's, but the front fan made a loud weird airplane like sound. So I thought the new fan was broken, I took it out and tested it on the table and it was dead quiet.

When I put it back in front of the case's grill, it makes the loud whirrrrr sound again. It seems like the airflow makes this sound when the fan is put on top of the grill.

The grill looks like this: http://inc.kuvat.fi/kuvat/i7silencio/silencio08.jpg
I tried all the fans I found in my house: http://inc.kuvat.fi/kuvat/i7silencio/fan_problem.jpg

The original is the most quiet but the clicking sound is so annoying and is the most hearable sound coming out of the quiet case. I know this sounds stupid, but can anyone recommend a low rpm (800) fan that might work better (quieter!)?

 

[jhansman]

This fan http://www.newegg.com/Product/Produc...82E16835426016 is extremely quiet, and while it does not move a ton of air, my system is staying cool. I have one one CM 212+ cooler and one venting my case; if I had room for another, I'd add it. Cannot hear either (truly) and am most pleased with them.

 

[beginner99]

Maybe mount the fan with anti-vibration mountings? (rubber thingies)
They usually come with "silent fans". I prefer bequiet!silentwings mounting system. fool proof.

 

[C1]

When this happens I just reduce the fan rpm till any noise becomes bearable. They are pretty large fans and so that should still work out okay. Make sure that something in or on the case isnt vibrating first though. If the fan blade is not balanced well then that will be an issue.

 

[Zap]

Either reduce fan RPM until it becomes quiet, or use fans made to have more static pressure. Notice how the Cooler Master blades are really wide?

 

[deimos3428]

See if you can get some more space (even 1/8") between the fan and the grill with rubber washers or whatever. The increased airflow may be vibrating the grill itself, and even a small bit of space can make a huge difference.

Also, try using the low or ultra low noise adapter that came with the Noctua. Mine aren't at all noisy at 5V/~900 RPM, and still provide pretty good airflow.

 

[jhansman]

One note about the Gelid fans-they come with 3-pin connectors, so they cannot be controlled. No problem for me; as I noted earlier, they are silent at 800+ RPM, so I wouldn't mess with the speed even if I could. They also ship with those rubber mount thingies, so no vibration noise either.

 

[Rinaun]

To answer your questions quickly:

The Noctua might as well be an airplane. They aren't the best quiet fans. I'd avoid them.

Secondly, buy this to control the voltages: http://www.svc.com/fsa-75.html . They are your best friends.

Thirdly, it is not the grill causing your sound issues. Those fans are pretty loud full-speed (the scythes).

Last, if you are going to replace the fan anyways, I'd suggest this one: http://www.svc.com/tr-fdb-12-1000.html
It's cheaper than the $20 noiseblockers, and it also comes in 1300 and 1600RPM.

Hope I could help.

 

[imported_mlt]

Thanks for the help.

The grill was actually what caused the sound issue. When you put a certain kind of fan on top of a grill with small holes, the air makes funny sounds when the blade moves so close to the holes.

I moved the fan a bit further away from the grille by making ~4cm "foam frame" between the fan and the grill. Sound went from loud to almost dead silent, and the air suction is still the same. I'm a bit surprised why the cases don't have some kind of tube inbuilt in them to avoid this.

The scythe 800rpm fans are actually so effective moving air so much air that the airflow is the only sound coming out of my case. When I turned them off (front intake and back exhaust), you can barely hear the PSU, CPU and GPU fans.

How can I run my 800rpm fans at 600rpm to test if the sound level goes a bit more down? Can I use wires or maybe the motherboards inbuilt fan controllers (Asus P8P67 EVO)?

EDIT: the adapters that came with the noctua fan seem to work, the rpm went down and so did the noise levels.. I'll monitor the temperatures to see how much the low rpm will cost in cooling efficiency

 

[deimos3428]

I moved the fan a bit further away from the grille by making ~4cm "foam frame" between the fan and the grill. Sound went from loud to almost dead silent, and the air suction is still the same. I'm a bit surprised why the cases don't have some kind of tube inbuilt in them to avoid this.

Looks like you've built your own custom fan shroud! For future reference there's an easier way, though: just take an old fan of the same size, and remove the inside bits -- instant 25mm shroud.

EDIT: the adapters that came with the noctua fan seem to work, the rpm went down and so did the noise levels.. I'll monitor the temperatures to see how much the low rpm will cost in cooling efficiency

The adapters provided with the Noctua just contain resistors to decrease the voltage from 12V to either 7V or 5V. That's what the small bump in the wire is, and you'll note it can get hot to the touch as it converts that excess voltage into heat.

These will work with any 3-pin fan, but be warned that some fans may not be able to spin up at 5V. (It takes more voltage to start a fan spinning than it does to keep one spinning.)

Check after installation that they'll start from a dead stop, or you may cook your system thinking they're running when they aren't.

 

[imported_mlt]

Looks like you've built your own custom fan shroud! For future reference there's an easier way, though: just take an old fan of the same size, and remove the inside bits -- instant 25mm shroud.

The same thing crossed my mind, I just didn't have any bad enough fan to destroy.

Check after installation that they'll start from a dead stop, or you may cook your system thinking they're running when they aren't.

Thanks for the advice! Seems to work now but have to keep my eye out..