My Silent PC project
My old case had several problems. I decided to design and build a case that would address this. The needs would be:

Someone mentioned MDF board on the Silent PC list and then I decided to build the case in that material, and adding dampening mats.

There is too much expensive tools needed in building in metal, anyway. 1cm copper would be cool, though. :) The case I designed had:

The lid is the simplest design possible. It's just four sides of the case, with holes cut out in the front. No buttons or indicator lamps. I will do something with the outside later, because now it's, frankly, quite ugly.

I tried various fans for the box. The most quiet is the 12dB Papst. The 14-19dB Enermax is not quiet.

Now, what was the outcome? Did it help?

So I had to work more on the noise and the fans. First attempt was to run the Papst at 7 volt. They run fine at 7 volts, but the case is not cool enough. So I ran 4 fans at 7 volts and 1 at 12 volts. It worked, but the turbulence came back.

I found simple temperature controlled voltage regulators on the net. So I decided to buy components and build them.

This worked very nice. Now the fans run at 8-10 volt and it cools enough while not creating any noticeable turbulence. And the CPU fan is inaudible when the CPU is cool enough. I also added an air duct for the upper fans to enhance the air flow.

I also build a control box, with thermometers and indicator and stuff. It's connnected via a 25 pin d-sub, so I can unplug it at leisure.

It consists of

The voltage regulator was very easy to build, given the right components. It needs three components, the bar graph LED, the bar graph chip and a fixed resistor.

Here's the final result with all the stuff added:

Final outcome is rather nice. Maybe 5-15dB. Not inaudible, but I can't hear it from 5 meters away and I can't hear it if I open the window to get some background noise. A little more audible (10-20dB) when it's hot.

Things to note:

Physical characteristics:
What's inside the case? This is what to have to be cooled: For discussions about silent PCs, see the Silent PC mailing list.