Sound absorbing cupboard for 4 PCs

I went nuts from the irritating noise made by the 3 PCs in my livingroom. At a given time the irritation was enough to start doing something about it. I wanted to have a flexible solution for at least 4 PCs. Two web pages I found somewhere at the http://groups.yahoo.com/group/Silent-PC group inspired me. First of all Erik Forsbergs' http://www.lysator.liu.se/~forsberg/silence_box.html airflow and casing ideas and for the sound-absorbing half-box at the rear Larry Mingus' page at http://www.makeitsimple.com/projects/case_noise/ . Thanks guys !

This is the airflow model. Cold air gets sucked in below, flows through the PC's, and hot air leaves the cupboard at the top. The extra long air outlet is there to minimize the fan noise. All airflow shafts have a soundproofing material layer. Both the air inlet and outlet are at the rear side, to minimize the noise at the front. The PC's fans do not generate enough airflow in the cupboard by themselves, so I installed two extra (big, but slow revolving) fans.

My first thoughts were about something like a kitchen cupboard, but soon I realised that although 4 PCs might fit in there, the soundproofing material and the ventilation shafts certainly would not. I finally came up with a cupboard intended for clothes; the 'Kusk wardrobe' from (ahem) Ikea :-P

Here are the first steps of the transformation after the initial putting together of the cupboard:


I removed part of the middle wall so there is one big space for the PCs. You can clearly see the air-inlet below and the air-outlet in the middle.	The 4 vertical holes are to be filled with soundproofing material through which the cable muck is lead. This is not enough soundproofing here, I needed an additional half-box too, see somewhere below.

	Halfway ready, the two left PCs are operational again (hey, I need my 7x24 internet connection :) The doors are flattened with some cardboard glued to the white middle part, ready for the soundproofing material. The air outlets are not quite useful yet.
	Finished ! Nicely packed and prepared for a fourth noise generator :o) The shelve the PCs are standing on were shortened for the air to flow by on the front. Same for the screened shelve above the PCs.
	With some of the black sound absorbing material removed you can see the fan at the end of the green sound absorbing plate. It is simply stuffed in a hole I made in the green stuff. It is not blowing at full speed, but definitely needed. I should make its speed temperature dependent, but these two fans are linked 110 V AC ones (220 V AC here as you might know) that I had lying around somewhere, and I dont have the temperature dependent electronics for it yet.
	A not-so-nice photo of the half-box hanging over the 4 cable-outlet holes at the back of the cupboard. It is open at the bottom and works quite well in removing some additional noise. Its inner walls have the black soundproofing stuff glued to it. The need for this patch shows that the cupboard should have been deeper than the current 50 cm. I hope this helps you in choosing yours.

The air leaving the cupboard is 30°C, mainly caused by only one of the PCs, it needs a bigger power supply.

Total costs involved: 220 € (cupboard: 175 €, 2.5 m² iso-fix (the green 3 cm thick sound absorbing stuff): 27 €, 2 m² iso-top (the black 3 cm thick and lumpy sound absorbing stuff): 18 €)