420 Magazine Background

How to dampen noise from PC fans

SmokeyMacPot

New Member
If you are trying to make use of a PC case fan, but finding it gets quite loud, this is for you!

You will need the following:
* Insulation foam strip (any thin foam should do)
* Heat-shrink tubing (from any electronics shop)

Step 1 - Preparing your mounting screws

Take your heat-shrink tubing and cut 4 pieces - each around the width of your fan mounting (Picture 2). Insert the screw into the tubing and shrink to fit (Picture 3).

You now have rubber coated screws to dampen some of the vibrations.

Step 2 - Mounting the fan
Take your foam tape, peel off the backing and place along the edge of your fan (the side facing the wall). Make SURE that all sides are covered!

As you can see, overlapping the tape is fine.

Screw the fan to your box wall tightly! The foam will compress leaving an air-tight seal around the edge of the fan.

The rubber screws coupled with the foam seal will stop vibrations from the fan, leaving only the sound of air passing through it. This can be reduced to silence by running the fan at 9 volts!

Contributed by: aallonharja
A much simpler approach is using one of those camping mats made of polyurethane. Cut a strip of the mat that’s long enough to run 3 times around the outer sides of the fan.

Make an opening for the fan that is slightly smaller than the fan with the mat, OR depending on your setting, make an frame for the mat/fan combo that you can fit on the inlet/outlet hole (out of wood or whatever).

Stuff/slip/slide carefully the fan - mat combo into the opening - simultaneously insulating any light and air leaks AND very effectively sound dampening the fan. It’s also possible to run wires through between the mat layers as it flexes to accommodate wiring.

Usually its possible just to make the opening and slip in the fan-mat combo, no screws etc needed. If the strip of mat extends in front and back of the fan, the sound of the fan (blades) and air rushing is also dampened.

Contributed by: Nexsus6
If mounting and noise are an issue, another great damper is silicone. If your fans are not near a direct heat source (unaffected by high temp silicone mixtures), you can effectively run a bead around all contact surfaces prior to tightening...Silicone maintains a certain elasticity after curing. Allows vibration to dissipate and holds screws tight.

Author: Steen / aallonharja / Nexsus6
 
Last edited by a moderator:

Roman

New Member
My fans are completely silent, the problem is the air flowing out the back of the duct. I extended the duct which cut down alot. But I was curious if their was a silencer of sorts a person could make to cut down on the sound of the air as it comes out the duct?
 

nova2006

New Member
im in the same boat atm, i have one big one pushing air in the box (from the back of a case,,
and a smaller more powerful one pushing the air out, ( was on top of processer)

the smaller of the 2 has got an annoying whine!, cut the end of a peat pot off
taped it ova the top, reduced a noise a lil.

will try ure heat shrink idear
regards
nova
 

Roman

New Member
Curious what does an accuator do? I noticed on the S&P fan site that they mentioned somethingn about one but never really understood what it was.
 

Lemon Paradise

New Member
I play with computers for my main job..lol
I have had the need to use fans for other purposes and to get it to run a little quieter, I will run a 12V fan off of a 9V adaptor, the rpms will be slower, and will make less noise...

You could also use the 120mm case fans, as they move more air, but at a lower rpm, so noise will be less as well..
 

SciFi

New Member
Silent PCs were all the rage a few years ago, and I learned quite a few tricks from building them.

You don't want the fan directly on any rigid surface. Anything you mount it to should have an insulation layer between it, and the fan, and that includes the screws.

I've seen lots of ways of doing this, from what he stated above with heat shrink tubing, to a friend who got a mud flap off the side of the highway (that had fallen off a semi-trailer), and punched out his own heavy duty rubber washers.

But as he pointed out above, the bigger the fan, the more amps you use (the more HEAT you put into the air too!), the less noise you get, as you're performing less RPMs to move the air. Those tiny 1"x1"x.5" server fans scream like a banshee.

Also to note, if a fan is rated for 12V and you're running it at 1-11V, and it's counting on those RPMs to cool it's own moter... It CAN cook itself, or shorten it's life.

Also to note.. the sleeve or shaft bearing on PC fans tend to be louder and wear out quicker. If you can get server grade, ball-bearing PC fans, you'll be much happier with less noise, and they last longer then the sleeve bearings.
 
Last edited:
As of today one of the best cooling fans from the computer world for cooling is the Noctua NF-F12 PWM Cooling Fan . They are the 120mm size and are made to run super quiet and have a 5 year warranty behind them. I am running a pair side by side in a box I built and they are silent when I run then at a reduce power setting. The fans come with load reducing cables built to take them from full power to about 75 % without buying an additional speed controller. I bought the speed controller as well but after trying the cables that came with the fans I rarely use it. I have them pushing air up and out thru the top of the box and into a homemade charcoal filer setup I made to cover the pair. Seems to work very nicely and and with the box in my bedroom it does not keep me awake at all as it is dead quiet unless I am standing at the doors of it.
I also insulated the box with 1/2 inch foam and covered that with 7mm Mylar.
The fans are mounted to the wood with 1 inch wide door insulation striping that is sticky on one side. I put 2 layers of it on the fans and the screws are installed thru a squirt of silicone in the screw hole to help with that part of the sound deadening.
 
Top Bottom