Low air resistance, low fan speed, low noise technique

Enclosures and acoustic damping to help quiet them.

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GuyClinch
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Re: Low air resistance, low fan speed, low noise technique

Post by GuyClinch » Tue Jun 28, 2011 2:04 pm

2) If higher airflow is needed, then the more open vents probably work better. There's something really annoying about the effect of air resonance in a mostly closed case with higher speed fans (or higher level of component noise); the noise becomes tonal. Personally I prefer the case to be completely open if the fans/noise is higher, this tends to keep the noise more broadband. Enclosing this noise just causes too much "booooom" effect.
This is a very good point.. I make no bones about it - I never go for 'silent' builds - I go for QUIET builds. I think actually a nice quiet 'woosh' type of noise is pretty pleasing. If you greatly restrict the intake you end up with the CPU or GPU fan really cranking up to compensate (if you are running a high powered build). And this is very annoying. I'd rather have several fans spinning at comfortable levels then one or two fans spinning like crazy.

Also the woosh type of noise will cover up HD seeks to some extent - and that is a pretty annoying noise as well - best to use a SSD if you can for this reason..

So the question is how much wattage is your build going to pull. Someone doing a Zacate build will likely be okay not moving much air.. OTOH I run a 6950.. So I really like to have my intakes blowing right to that video card..so it doesn't have to spin up much.

I don't agree with the OP theory on filters at all though. They are very beneficial. If you use both positive pressure and easy to clean fan filters you are going to have a very nice and neat case. The FT02 tested out to be one of the QUIETEST cases and one of the BEST COOLING cases on the market - and it uses this theory. But you can do that with many regular cases too.. I mean who really needs optical drives nowadays... one external one is fine for me. I barely use em.

Mr Spocko
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Re: Low air resistance, low fan speed, low noise technique

Post by Mr Spocko » Mon Aug 01, 2011 4:24 pm

I use no fan filters reason?

Unless the entire case is sealed dust will get in somewhere. But I'm not in a very dusty environment so that might also be a factor. I see cases with filters and then gaps letting unfiltered air in (new Silencio review noted!) pointless to have that. The Sonata original filtered at the front and nice holes drilled in the case to let lots of dust in! I could go on there are many examples.

Spaces between drives suck dust in too.

ces
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Re: Low air resistance, low fan speed, low noise technique

Post by ces » Mon Aug 01, 2011 5:50 pm

Mr Spocko wrote:I use no fan filters reason? Unless the entire case is sealed dust will get in somewhere.
That is not applicable if you maintain positive air pressure in the case. Then the air leaks outward.

NeilBlanchard
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Re: Low air resistance, low fan speed, low noise technique

Post by NeilBlanchard » Tue Aug 02, 2011 4:02 am

Dust still gets into positive pressure cases, through the fans. Where there is air flow, there will be dust.

ces
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Re: Low air resistance, low fan speed, low noise technique

Post by ces » Tue Aug 02, 2011 1:31 pm

NeilBlanchard wrote:Dust still gets into positive pressure cases, through the fans. Where there is air flow, there will be dust.
Exactly... that is why you should use filters on incoming fans. The original comment was about not using filters.

Mr Spocko
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Re: Low air resistance, low fan speed, low noise technique

Post by Mr Spocko » Tue Aug 02, 2011 3:56 pm

Dust still gets in via other areas suction pulls it in even if all the intake fans have filters.
You could argue it's less and I won't disagree..

But as I pointed out some cases have some obvious openings which let quite a bit of air/dust in and thus rendering any dust filters of lesser use. I'm not against them per but it's just something I've found over the years. The OP was suggesting that filtered fans have to work a bit harder/faster thus generate a bit more noise. I can't say that is an illogical point of view to take.

The original Sonata case was popular built quite a few of those (people like the look) but it was a disaster dust wise as the front filter was pretty much useless because the drilled out ANTEC holes just let tons of dust in near your PSU! (never mind the front USB/headphone/mic sockets another dust collector) For what it was worth all the front filter did was stop airflow going to the HDD's and mobo. That is a stand out one of the worst dust wise I have used the Mk II Sonata not so bad as they didn't have the holes on the case sides.

Sooty
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Re: Low air resistance, low fan speed, low noise technique

Post by Sooty » Wed Aug 03, 2011 6:06 am

Just carried out a similar experiment as Katana did, holding a Nexus 92mm (1500rpm) against an Antec P150 (same as Solo afaik) filter assembly. Air flow reduced by about 70% when trying to pull air through the filter. Shocked! :o Even pulling through just the honeycomb metal filter holder, there seemed to be a little reduction in airflow. The filter’s going in the bin, and I might cut out the grille.

mistaspeedy
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Re: Low air resistance, low fan speed, low noise technique

Post by mistaspeedy » Sat Jan 05, 2013 5:43 am

I totally agree with many of the points raised in this thread.
I have cut away the mesh on my side panel, front panel and rear panel... my fans are now a lot quieter and push more air.

I have a Spire Sonex case: http://www.spire-corp.com/main/product_ ... rodID=1154

To me, the front panel has a number of design flaws that can easily be rectified with a bit of work. For the benefit of those who have this case or will buy it, I'll go through what to do. It may also give you ideas on what to do with your case.... as each case is different and has its own advantages and flaws.

#1 - When you take off the front mask, you will notice that the front intake fan is attached to the front mask, and not the metal of the case. (it probably looks a bit better this way, and reduces noise in comparison to if it had been mounted on the mesh).
1a - the entire front mask has dust filters on it, including each 5.25" and 3.5" bay, and in front of the intake fan. But they put a hole on both sides and the bottom so air can bypass the filter! Why on earth put so much effort into dust proofing when dust can just get in that way?
1b - the intake fan does not make contact with the mesh on the case when the mask is attached, and therefore a lot of airflow gets lost.
1c - the intake fan is about 20-25% higher than it is supposed to be, blowing air into solid metal for 20-25% of its height.
1d - the mesh allows little air through and makes the fan somewhat louder (when you actually place the fan where its suppoed to be).
1e - the supplied fan is relatively quiet if your system is not too quiet, but if you have a very quiet system you will notice noise from it.

The solution:
I cut away the mesh on the front panel. (with a pocket knife). I detached the fan from the front mask and attached it exactly where it is supposed to be - making contact with the hole I cut (I cut the mesh out) at the proper height (there were screw holes there, a simple matter of just screwing the fan on there).

Sticking my face down inside the case I notice a huge difference. (system noise and temps fell too). There is now actual airflow coming in from that fan, as opposed to before.
As for the dust getting in, I am not worried about it... I will periodically clean out my system.

The last step will be to buy a really quiet fan for the front intake which I will control with a fan controller.

Here is a pic of the front with the mask off, and my side panel off so you can see it: http://i.imgur.com/DR8jB.jpg
I will add another side panel fan and cut the remaining mesh off too, and will smooth off all the edges and probably add a finger guard to each fan.

The end result is a very quiet pc that has enough airflow :)

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