DIY case that is very very quiet

Show off your quiet rig.

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tobsco
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Joined: Wed Apr 15, 2009 12:57 pm
Location: UK

DIY case that is very very quiet

Post by tobsco » Fri Jun 19, 2009 12:57 pm

This is my very DIY build. I've tried out many ideas along the way and it all was made up as I went so there are still many improvements to be made and features that no longer serve any purpose.

The end result is a resounding success, I have to try very hard, and often fail, to be able to hear it and I'm in a very quiet room. Plus it cost me very little to build, never a bad thing, and I enjoyed the process.

The key features are:

Low power cpu with a large passive heat sink. Pretty basic really, heat = noise.

2.5" hard drive in custom enclosure (the part I'm most proud of). I made a simple box out of 3mm aluminum then filled it with a mixture of brass swarf (the shavings that come off when machining) and flexible silicone sealant. I placed the drive in a plastic bag, put it in the middle and let it set. I was aiming to make something that would conduct heat but insulate sound and vibration, and I succeeded, particularly with the heat, drive is currently at 32 degrees and was at 28 when the front fan was on. Noise is reduced significantly though a slight whooshing noise can still be heard and vibration is all gone.
There are several large improvements I can think of with the making of this but I think fundamentally it is a very good idea. I wrapped it in lead a few days ago to try and get rid of that last bit of sound and it has helped a little.

Indirect air path in non resonant, sound absorbing case I started with a very simple wooden box as it is easy to work with and will absorb vibrations. the indirect sound path was one of the last features to be put on and made a surprisingly large difference. Definitely something to work on with the next build.

The hardware is

Athlon 3500+ Venice core
Asus Socket 939 motherboard
2Gb OCZ ram
Zotac 9400GT
WD Scorpio Blue 250Gb
ebuyer value psu with forgotten model scythe fan
scythe 1200 fan @ 3-4V
Nexus fan at 7V when used
Scythe Ninja

Not the fastest machine but I had to get rid of my opteron 175 when I learnt what TDP meant.

Temps are CPU - 26'C Idle, 52'C Load, HDD - 32'C GPU - 43'C Idle

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Front intake withindirect airflow path and foam
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Hard drive covered in lead
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Rear view
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Front intake fan, soft mounted to an old fan chassis via some rubber foam to give the air a longer path before it hits the front plate
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Side view
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Hard drive enclosure being built
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Hard drive enclosure before being wrapped in lead
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thejamppa
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Post by thejamppa » Fri Jun 19, 2009 1:56 pm

Very nice. I like the concept you made for front fan. Now its not looker, but its robust and aslong it works, that is the main thing. IMHO that is excellent start up for further imrpove the case.

I really like the HDD enclosure.

However Back fan muffler really needs soft pad and perhaps something more around, since as it is, sound just escapes from side and bounces back from the hard back plate.

But very original case that has a lot potential. I am sure information in this site will help you improve your case.

Hmmm... I kinda already see that PSU would be turned upside down so its intake would be on top, isolated from inside the case, having its on intake section.

psiu
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Post by psiu » Fri Jun 19, 2009 5:52 pm

I just want to point out that you, like everyone on here, are insane.

LEAD?!?!? :shock: :D 8) I love it!

ghitz
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Post by ghitz » Fri Jun 19, 2009 8:27 pm

I thought I have seen it all. Ghetto but original. :D

BillTodd
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Post by BillTodd » Sat Jun 20, 2009 6:27 am

Best thing I've seen here in ages :)

Love the HDD enclosure - I looked at Al turnings prior to playing with my gel packs, but using brass, a much better material since it is both springy and conductive, never occurred to me :)

Next, you have to move towards fanless cooling - build a chimney around that Scythe and see how much heat it'll move under its own steam ;)

Bill

Xobim
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Post by Xobim » Sun Jun 21, 2009 11:08 am

Ghetto mod indeed. I love the air deflector that's fixed with two thumbtacks. :)

And is that really lead, or straw? It looks like it is made out of very small shards that might enter your harddrive through its airholes...

theycallmebruce
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Post by theycallmebruce » Sun Jun 21, 2009 11:17 pm

Very nice, a lot of DIY spirit in this one! Any plans to paint it now that you're done?

I agree with BillTodd - try going fanless and see what your temps are like!

tobsco
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Joined: Wed Apr 15, 2009 12:57 pm
Location: UK

Post by tobsco » Mon Jun 22, 2009 2:33 pm

Thanks for all the comments, I think I'm going to start on a new case, though I will make a proper back plate with some foam on it as the one on there was only a quick test thing and as thejamppa pointed out, it's quite flawed.

I'm torn between going nice and open with extra heat sinks poking into a chimney, and going all out on the indirect air path idea, having the air snake round a channel on the outside of the case before entering the main body then have a fan suck the air out through the heatsink and through more gentle twists round foam. The second idea would be much more fun to build, so I'm leaning that way.

I'm also going to have another go at the hard drive enclosure, using a wider range of sizes for the brass to improve the packing density and a nice runny silicone to fill in all the gaps. And don't worry Xobim there is sheet of plastic to protect the hard drive from the brass shards, crushing the drive is what you have to watch out for.

And no, I've no plans for making this thing look good, though I might put some effort into the next one, maybe use a nicely veneered plywood with brass detailing. This guy http://steampunkworkshop.com/victorian-all-one-pc has some nice ideas.

BillTodd
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Post by BillTodd » Tue Jun 23, 2009 4:18 am

having the air snake round a channel on the outside of the case before entering the main body then have a fan suck the air out through the heatsink and through more gentle twists round foam. The second idea would be much more fun to build, so I'm leaning that way.
I suppose the question here is: Is the baffle arrangement going to restrict the airflow to such an extent that its sound reduction is offset by the need for a substantial fan to maintain the required airflow?

If you can get rid of the heat without fans baffles become unnecessary.

http://homepage.ntlworld.com/bill_todd/ ... part2.html

tobsco
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Post by tobsco » Tue Jun 23, 2009 2:02 pm

That is exactly the question. I have put a bid in for a huge heatsink on ebay, 300x180mm but still like the the idea of the baffle and have come up with this as an idea

Image

BillTodd
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Post by BillTodd » Wed Jun 24, 2009 4:54 am

At the risk of teaching granny...

You'll need to pay attention to sealing the box; making sure that there is no gaps where the sound can escape prior to being 'forced' along the baffles, and pay attention to the material used for the case to stop sound transmitting straight through the sides.

e.g.

Make it massive - just use thick ply or mdf (or chipboard)
Or, laminate dissimilar materials to increase damping - e.g. thin-ish ply with bitumen damping panels sandwiched in between.


Take plenty of pictures and post them here - I love DIY projects :)

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