Pangit’s PC Silencing Project “On the Cheap”

Last updated: 24 Aug 04

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Filtering

Updated 24 Aug 04

I recently moved house and the new one is very dusty for some reason. As a result the inside of my PC (particularly the main heatsink) was getting clogged with dust and sending temperatures up. So rather than clean it our every month, I decided to go for a filtering solution. Taking inspiration from Silent PC Review as usual and particularly the guru of filtering, Bluefront, I found a pleated paper Briggs & Stratton filter from my local lawn mower shop.

Here is my first attempt, attaching the filter to my front intake (previously a gaping hole, see below).

Of course for filtering to work, you have to seal up all other holes in your case. So I diligently taped up every single gap or hole I could find, including gaps behind input ports, PCI cards and around drives. Although I have an intake fan this is a slightly negative pressure case (due to the exhaust fan + 120mm fan in the FSP300-60PN), so there is a risk of dust being pulled in through the optical drives. Fortunately they both have rubber seals on the drawers so this shouldn't be a problem.

Once I fired the system up and run it for a while, as expected the CPU temps were up by a few degrees. Hard drive temps have not changed much which is good.

However, the temperature controlled fan in the PSU started ramping up sooner and making considerably more noise than before. This was obviously due to the restricted air intake, so I figured that by using a bigger air filter to compensate for the restriction. Following Bluefront's lead, I decided to put another filter in the bottom of the case, being the only place with enough area to do this. I actually found two larger filters which would fit in the available area (the same Briggs & Stratton ones), cut large holes in the bottom of the case and taped them to the bottom. I also raised the whole case up on castors to provide an air gap under the case. This increased the total intake area from about 81cm2 to over 300cm2, a four fold increase.

Here is the finished article: Naked! Fortunately this ugly mess of duct tape is covered by the bezel:
Inside: Underneath:

Right side, showing ribbon cables neatly tucked out of the air flow: 		I've also recently upgraded my PSU to a Fortron Source FSP300-60PN, with the 120mm temp controlled fan, as seen here:

While it's still not as quiet/cool as filterless, it is definitely acceptable now and no noticeable dust inside the case. I've only been running it like this for a few weeks, so I'll see what it looks like in a couple of months.

Hard Drive Suspension/Ducting Mod

Updated 07 Jan 04

I finally decided to put my Hard Drive suspension/ducting idea into action.

I created this drawing when bored at work a few months ago, based on various ideas on the www.silentpcreview.com website, particularly Aphonos' 2 Drive suspension system. I decided to develop it a bit further with a few other ideas I wanted to incorporate.

I have two drives, a reasonably quiet Seagate Barracuda V 60GB and a noisier Barracuda 7200.7 120GB. My most important consideration was cooling the hard drives without restricting airflow to the rest of the case (they are the most important components on my system), closely followed by quietness.

The main things I wanted to achieve were:

Here's how I did it:

  1. I cut the hard drive mounting brackets out of an old case, and cut them to the size I wanted, just big enough to hold the drives with a gap big enough to mount an 80mm fan at one end.

  2. I drilled mounting holes for the drives and cable clamps. I kept them separate simply because I didn't have long enough screws to go through the cable clamps and hard drives, but this also means I can remove a hard drive without taking the whole thing apart.

  3. The fan is mounted at the rear end of the hard drives with rubber bands looped through the fan holes and hooked onto the cable clamps, which effectively decouples it. I angled it up towards the graphics card by looping the rubber bands through different holes. I have recently reolaced the HSF on my Radeon 9000 Pro with a passive HS, so the fan should help keep it cool. However I may remove it completely once I've done some testing as it may not be needed at all.

  4. I also decided to completely open up the front vent on my PC case, since I was removing the front fan anyway and wanted to match the opening up to the hard drive duct for maximum airflow. As usual I duct taped any other holes to prevent air leakage.
     
    Here you can see right into the duct, with the two hard drives at the top and bottom, and the fan at the far end. The brightly coloured bits are cardboard (taken from a Cheerio's packet!) to block the gaps on either side of the fan.

  5. I put strips of foam between the duct and the front of the case, partly to prevent direct contact with the case, and partly to seal around the air intake.

  6. I cut the bottom off the original 3.5in drive rack to leave more space below it for the new system, so it now only has room for 2 drives. [before & after photos]

  7. I mounted the frame of an old dead floppy drive just below the real floppy drive, and ran the elastic shock cord from this, through holes drilled in the bottom of the case and up the other side. This is held under moderate tension and can easily be adjusted. The whole hard drive assembly was then attached to the elastic with the cable clamps.

  8. I took a few tips from Ralf Hutter's excellent cablegami work, to keep the cabling as neat as possible and out of the way of the airflow. Both hard drives now run off separate IDE cables so I can route them out of the way of the fan. I've given up on home rounded cables (except for the floppy drive), as this seems to work and look better.

The finished article. You can also see my other recent mods: the large passive heatsink on the graphics card (note the fan pointing towards it), the SLK-800A, the panaflos, the hole in the PSU, and the old 486 heatsink to passively cool the northbridge.

Here it is from the outside:

You can see the hole I cut in the front bezel to improve airflow into the intake (there is no fan behind the chrome grille). The slot in the bottom of the bezel has been widened too. The hole in the side of the case has now been blanked off. I may re-do the duct from the side to the CPU fan, but that may mess up the airflow into the case at the front intake, which relies on negative pressure caused by the exhaust fans.

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