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Help with my potential custom case build :-)

Posted: Fri Sep 07, 2007 3:12 pm
by WBaS
First off, I'd like to say that this design is a direct result of the DIY project cases/mods I've seen on this site, I'd like to thank all of you, you've been my inspiration. My current computer is very loud, so I figured it's time to change that.

Current rig:
Processor: athlon 64 x2 6000+ (stock HS)
GFX Card: xfx 7900GS (stock HS)
HDD: Old Western Digital PATA 7,200rpm 80GB
Optical: Not too important in this case, Phillips DVD/CD burner (loud when full speed, which is rarely running)
Mobo: Gigabyte M61P-S3
Sound Card: Sound Blaster X-Fi
Case: X-Superalien (which I fully reget buying, but hey... it was my first time haha)
edit: Forgot another important part!
PSU: corsair hx520 (decided to buy it after reading your review)

I don't have a lot of money to spend so I'd like to stick with my current components (with the exception of the case obviously).

As you can see I drew a quick sketch in paint to show you what I am thinking of doing.
The brown coloring represents wood (probably plywood), the material that I wish to use to make the case. The HDD would be suspended using the elastic rope method. The fans will either be attached using the foam/elastic method or the zip tie/rubber hose method.

My questions are:
1. Will this provide enough airflow for my system, I'm thinking of using the scythe 120mm fans recommended on this site :?:
2. I saw in the "Bluefront's Lanboy, Part 3: Acoustically Muffled Case Fan Box" article that "safety mats" can be used for sound damping. In my case would this be the best option, or would something like car roofing insulation, or vinyl tiling work better :?: I would like to keep weight to a minimum (but still inhibit vibrations) because I do move my computer back and forth from college on occasion.
3. This being my first attempt at a custom case & silencing a pc, could you also please comment on the effectiveness of this potential case with my current rig :?:

Thanks everyone, hope to hear from you soon! :D


Posted: Fri Sep 07, 2007 3:43 pm
by ddrueding1
That looks pretty good. The only thing I would recommend right off is to move the HDD somewhere near some airflow. Suspending it in the air duct underneath would work better. Be sure that your GPU gets some of that direct fresh air as well, perhaps with a small duct?

Posted: Fri Sep 07, 2007 3:54 pm
by WBaS
Great ideas thanks! What about the damping material (question 2)?

Posted: Fri Sep 07, 2007 4:12 pm
by ddrueding1
Damping is an interesting question. Are you just trying to prevent the sound from escaping via vibration/resonance? If so, the plywood itself should do just fine. If you are trying to absorb the sound inside the chassis, so less escapes through the openings, that is a much bigger problem. Different materials absorb different frequencies with different degrees of success. In this I am certainly no expert, but I would be interested to hear what others around here have to say.

I'd imagine the first step would be to identify the characteristics of the noises your machine will produce. The PSU and 120mm fans will likely be negligible, leaving the video card and the hard drive. The hard drive can be buried deep in the system, making it less significant. But the video card will certainly be the loudest thing in the case; and it's small, high-speed fan with produce a higher-pitched whine than anything else in the system. It's also right near the back of the machine and can't be easily isolated.

Posted: Fri Sep 07, 2007 4:28 pm
by kittle
Your going to want some kind of sound deadening stuff on the plywood itself -- otherwise it will endup vibrating when you least want it to. if not from inside noises, then from outside ones.

a few options:
1 - dont use plywood. Get some MDF (Medium Density Fiberboard). Heavy but very vibration free.

2 - Use thick plywood - 5/8 to 3/4 inch thick. Somewhat heavy, also probably cheaper than MDF, but potential to vibrate more.

3 - For thinner plywood, visit a car stereo store and look into adhesive sound deadening materials they have available. It wont take much to cover the inside of your case. however this stuff can also get heavy.

4 - go visit a carpet store and get some carpet pad remenants for free. Or visit Home Depot and buy a couple square yards for very little. Staple this to the inside of your case and it will help stop any resonance from building up inside your case.

Options 1 and 2 should not need anything attached to the inside of your case.

Other things you can try is to buy foam rubber from a craft store or some 'snow' from blocks from a craft store. One thing I did for making DIY speakers (they need internal damping too) is to buy a cheap foam mattress pad and cut it up. A twin sized pad cost about $17 and was WAY more than I needed, even for 4 full sized speakers.

GL & please post pictures when your done!

Posted: Fri Sep 07, 2007 4:41 pm
by WBaS
Ok on the pictures, I might even post a revision of this one by the time I'm ready to build.

I was thinking of using 1/2" plywood with some kind of lining material. I am definitly a fan of making this as cheap as possible so the carpet pad solution looks pretty good. I also like the matress pad idea. If I go with one of those, I might even try using something else as another layer, just to add extra resistance for a wide frequency range. I'm really interested in these "safety mats" that Bluefront was using. Does anyone have any experience with those :?: The sound stero store isn't a bad idea either, but I think it's too high class for me 8) .

Posted: Fri Sep 07, 2007 8:20 pm
by Auberon
I'm thinking, if you want to undervolt that fan and the PSU doesn't normally push out a lot of air to start, that you might want to rethink forcing the air downwards out the back. A little bit might be fine, but forcing it halfway down the case might just lead to a very hot computer.

So you could extend the top of your baffle, add some more foam at the top, and leave a largish slot for the hot air to escape through more naturally.

Posted: Fri Sep 07, 2007 10:29 pm
by VanWaGuy
Hey WBAS, nice start on a system design,

I like the angled intake air fan, focusing on the GFX card looks clever.

Some day, I will have to learn some woodworking skills and attempt this too.

The baffle on the output air side looks like it should capture some sound.

As was already mentioned, try to get the HDD into the air flow.

On the input air side, I might consider making the case a bit taller so that it could accomodate another fan. At first I thought maybe right above the filter blowing up, but that might get blocked by the cound card, so maybe a bit towards the front. (I think a second fan will help make sure that the system is positive pressure, hopefully not allowing any dusty air to get sucked in around the drives, etc.)

Filters can really cut down on the airflow, so I might be tempted to also try adding more air input filter area. Adding another filter on the back, front or between the current filter and the front wheel would probably help with the restriction that the filter will cause.

Except for the hard drive, I bet things would work pretty well, just adding ideas that I would think about trying if this were mine.