Noise Reduction On The Cheap

[bigdawgfoxx]

Can u just pull the 40mm fan off?

[FlyingDutchman]

Hi Skillian,

Ok, let me first try to explain why your PC is kind of noisy right now.
Tomorrow I'll have time to explain how you can do it in a different way, and bring down noise considerably.

From your links i found the case has several venting openings, at the top, two in the rear, in the side, and in the front (low down).
I suspect you have 1 fan in the side pumping air in, one in the rear pumping air out, and the PSU pumping air out. Then there is the CPU fan recirculating air. Then you probably didn't close any openings not fitted with a fan. (Right so far?)

The supply of fresh air brought in through the side will manage to keep you CPU cool, but then the "polluted air" (It has been warmed as it has cooled the CPU, thus it is polluted) is allowed to spread freely through the case.

Now you have 2 fans expelling air from the case (PSU-fan + the case fan), and one feeding air into the case, directly to the cpu. The 2 expelling fans probably displace more air than provided by the fan in the side panel, so they will suck in some additional air through the other vents. It is a pity 2 of those vents are located right next to the expelling fans, so air will take the route of least resistance and enter the case right next to the expelling fans. You have a "cooling-air short circuit" here.

Your cooling is in-efficient and thus the fans have to work overtime to provide enough cooling.


I had to guess a lot here, so tell me where I guessed wrong.

The PSU's intake, is it all in the front (where the cables exit), or are there also holes at the top?

Originally posted by Skillian@5 April 2004 - 19:32
Main question is: should I replace the PSU fan with a thermally controlled case fan such as this Antecand stick the temp sensor to the side of the PSU or would this be dangerous?

The web site says: "Built-in temperature sensor" , so the sensor is probably located under the fan's hub. You would be very lucky when you could make yourself a good "temp controlled" PSU by modding it with this fan.

More tomorrow....


EDIT: 12 hours later.....

Finally found better pictures of the case in this review .
The review isn't very favorable, I mostly agree with reviewers.

Most 'bad features' can be cured though without spending loads of money.

[Skillian]

You were pretty much right about the assumptions you made. The vent at the top is pretty useless, not much room for air to flow and the turbulence this causes makes it noisier than it should be, so I don't use a blowhole. The front fan would have absolutely nowhere to draw any air from, so thats pretty pointless too.

Should I close the openings I'm not using?

The reviewer is right about the side fan, is doesn't flow over any important components, but it does let a lot of air in, and makes quite a difference to my temps. I also don't really seem to have a dust problem.

The exhaust fan grill again doesn't let enough air out and causes noise, but I use it because it does help, and I sometimes unplug that fan at night. I'd like to cut that grill out really, but I'm not sure I have the tools.

The power supply only has a grill at the back where the wires come out, nothing underneath unfortunately.

Thanks for taking the time to check it out for me, it's appreciated.

[FlyingDutchman]

Originally posted by Skillian+6 April 2004 - 20:43--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Skillian &#064; 6 April 2004 - 20:43)</td></tr><tr><td id='QUOTE'>You were pretty much right about the assumptions you

made. The vent at the top is pretty useless, not much room for air to flow and the

turbulence this causes makes it noisier than it should be, so I don&#39;t use a blowhole. The

front fan would have absolutely nowhere to draw any air from, so thats pretty pointless

too.
[/b]

You could reduce turbulence, and the sound it makes, by mounting a fan on top of an old fan-frame. Just take an old worn out fan, break out the spokes, and use the frame to mount the fan on.

Originally posted by Skillian@6 April 2004 - 20:43

Should I close the openings I&#39;m not using?

Generally speaking: YES &#33; , unless an opening has been identified as an air-intake of course.

Originally posted by Skillian@6 April 2004 - 20:43

The reviewer is right about the side fan, is doesn&#39;t flow over any important components,

but it does let a lot of air in, and makes quite a difference to my temps. I also don&#39;t

really seem to have a dust problem.

The exhaust fan grill again doesn&#39;t let enough air out and causes noise, but I use it

because it does help, and I sometimes unplug that fan at night. I&#39;d like to cut that grill

out really, but I&#39;m not sure I have the tools.

When fresh air doesn&#39;t reach "components to be cooled" and doesn&#39;t thoroughly mix with hot air before it gets expelled, it&#39;s just a waste of "expelling capacity".

Tools needed are "tin snips", a "nibbler" or a "dremel-like" gadget. Those that have worked with "tin snips" before swear by it. Be aware there are "right walking" and "left walking" tin snips.

<!--QuoteBegin-Skillian@6 April 2004 - 20:43

The power supply only has a grill at the back where the wires come out, nothing underneath

unfortunately.
........[/quote]
Not really a problem though.

I have to work on an answer for you, and can&#39;t do it tonight anymore.
You can start searching for low revving 80 mm fans (< 2200 rpm) available to you.
2 2800 rpm fans can be used too as rear-case-fans when you connect them in series, effectivly running them @ 6 Volts.
Don&#39;t buy yet, just see what is readily available.

I&#39;ll get back to you tomorrow, or the day after.

Regards.

EDIT:

See if you can find this Nexus-Real-Silent-Case-Fan.
It seems to be made for you. When you can&#39;t find it, that shop ships internationally.

[clocker]

Skillian,

After months of nonstop experiments with air cooling I have a few pointers....get out the salt.

1) If possible, always use a 120mm fan. It will move more air with less noise (especially if run on 5 or 7 volts).

2)Blowholes will work, but they need to be fairly large...in your case apparently a 120mm hole will remove the stock vents...I&#39;d do it.

3) Try flipping your rear fans to bring in air, your chip/heatsink should benefit. Remove the stock grillwork NOW.

4) At the same time reverse the fan on the back of your PSU so it is an intake.
(Do this only if you install the blowhole fan and your PSU has grillwork on the front for air to escape....)

5) Leave your stock front fan in place (ineffective as it may seem)&#39; it won&#39;t hurt.

Should you implement all these changes you will have a lot more air coming in (voltmod all these fans to run on 5/7v) and only one exhaust fan...the 120mm blowhole fan ( run this on a rheostat to balance flow/noise).

Such an arrangement has worked quite well for me...your results may vary.

[Skillian]

OK, the quiet fans I will have a look for - I did find these Zalman Stealth Fans - at 20dBA and a slightly higher airflow than the Vantecs they sound pretty good. I&#39;m thinking one for the PSU and one for the CPU.

I&#39;ve had a look around and I don&#39;t have any of the tools needed for cutting the grills or a hole in the top of my case. In theory I could buy them but I am trying to keep the cost down. What exactly would I need. Tin snips to cut the grill and some sort of sanding tool to neaten it up I guess. Those wouldn&#39;t suffice to cut a hole in the top though, as I would be cutting through sheer metal. Perhaps I could perform the easier modifications now and look at doing that later, when I have a bit more money and I can see clearer what needs further work as regards noise and cooling.

Remember my goal here is noise reduction, so I am wary of adding more fans, though I understand the concept that if the cooling is more efficient, less power would be needed to the fans, thus reducing the noise.

Do you think I should try reversing the exhaust fans even if I don&#39;t have a blowhole? I suppose that&#39;s something I could try and see for myself, I&#39;ll have a go tonight.

[clocker]

CompUSA sells a reasonable set of sheetmetal nibblers for ten bucks...they are what I have been using and work quite well.
With a bit of practise you can make a hole so neat that it really doesn&#39;t require any clean up to speak of.

The Zalman fans are quiet, but I&#39;d think twice about using one on my CPU...big performance hit with the low flow.

Go ahead and try the fan reversal...you have nothing to lose but time.

[Skillian]

Is that what I should ask for, sheetmetal nibblers? I don&#39;t want the hardware atore guy to laugh at me

I was also wondering if that airflow was strong enough. Does anyone know what the CFM of a stock AMD fan is (that&#39;s what I&#39;m using currently using)?

Is it fair to compare the air flow of a 60mm to an 80mm? i.e. if the airflow of the AMD fan is 30 CFM, should I expect the same performance from a 30 CFM 80mm fan?

[james_bond_rulez]

wow this is amzing....we are into the aerodynamics of the computer air flow now...

this is deep stuff

y&#39;all are here wastin&#39; ur time on expensive noise reduction ideas but in the end, ur attempts are all futile, with all the money spent modding the case and buying fans when you could&#39;ve bought a cooling system for the same amount of money.

Why not use a water cooling solution? it&#39;s quiet and doesn&#39;t require fans...well except for the psu

there is one on sale on ebay, grab it before somebody else does

Cooling System

btw i am not the seller, i am not that low

[Skillian]

These are cheap noise reduction ideas, not expensive ones. If I had loads of money I&#39;d probably get a Zalman Flower CPU cooler and one of those expensive low noise PSUs.