Design idea for silent mATX case

Enclosures and acoustic damping to help quiet them.

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silentg
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Design idea for silent mATX case

Post by silentg » Sat Nov 26, 2011 7:33 am

At the moment my main computer is a 5 year old C2D desktop that I made fairly quiet. I'm thinking of replacing it with something new. One of the main goals is to have it completely inaudible at idle. (Maybe <16 dBA @ 1m?) I'd also like to have 4 HDDs suspended. I've looked for different cases from ITX to big towers but it is somehow hard to find a perfect one. Somewhat inspired by the Silverstone Fortress and Antec Lanboy Air I tried to put something together in Google SketchUp:

Side view: - - - - -Side view 2: - - - Top view:
Image - - Image - - Image

4 x 140mm fans in the bottom should provide decent airflow through the case. I'm thinking that i5 with big HS + passive GPU (something like 6770) + passive/semi-passive PSU might be cooled without any other fans?

Total dimensions of this design are 330 x 330 x 530mm. It turns out the the total volume of this case quite big for the mATX one - over 57 liters. There are some wasted space but if the bottom would be based on 4 x 120 fans, wouldn't the HDDs block too much airflow?

Haven't really figured out the top design of this case but I think I've left enough room for the IO cables that could be turned 90 degrees inside the case and exit from the side. There should also be room for optical drive, but I won't need it.

Not sure where the top ventilation holes should be placed for the air that gets out. I think I'd prefer to have these at the side because sometimes it is convenient to keep things on top of the case. It would also be nice to have usb ports and on/off button in the top.


Since I don't have a lot of experience in building things I not sure if going to build a custom case but it would be very interesting to know what spcr people think of this design?

edh
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Re: Design idea for silent mATX case

Post by edh » Sat Nov 26, 2011 11:53 am

That is BIG for a uATX. That's simialr to some EATX cases.

I'm not convinced that a 140mm fan setup will help as there is less choice of 140mm fans out there than 120mm fans. If youa re going to go bigger, why not go MUCH bigger and get a pair of Silverstone 180mm fans arranged side by side?

Why do the hard drives have to behung side on like that? Arranging them end on instead would still give you some airflow between them but with much less impedance of airflow to the other components. As it is, you're going to be blocking the CPU heatsink with a load of hard disks. I can't see why you need that much airflow around the disks? Unless you're running 15000rpm server disks (and even if you are) you're just putting far too much cooling over them. I assume mass storage is a requirement here due to the numbers of disks. What kind of disks were you considering and what volume of data are you planning for?

If you for a pair of 180mm fans at the bottom then position one blowing over the CPU and motherboard and another blowing over the graphics card, the disks and the PSU. This would allow a much narrow and shorter design with only a further 80mm of depth.

A passive PSU would get more than enough airflow to work well in such a setup.

Edit: for that matter have you looked at the Silverstone TJ08E?
http://www.silverstonetek.com/product.p ... 03&area=en

silentg
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Re: Design idea for silent mATX case

Post by silentg » Sat Nov 26, 2011 12:43 pm

Thanks for the feedback. I'm using use WD green 5400rpm HDDs, not server ones :)
For some reason I like cubed like shape where width and depth are same.. Sure, with two 180 fans volume could be decreased.

But in terms of airflow, would it also help if I move fans to the top the HDDs, so that these will be blowing air from HDDs to CPU/GPU/PSU?

Sunrise
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Re: Design idea for silent mATX case

Post by Sunrise » Sun Nov 27, 2011 4:46 am

How about basing it on the FT-03 but flipping the PSU on its side so it doesn't block the airflow, then using a single 18cm fan in the bottom, slightly off center to make room for the PSU?

You can have a spot for an exhaust fan above the CPU cooler in case it's needed. You'll need an exhaust grill there anyway.

Essentially this would be your case with the PSU moved below the CPU, against a side wall, and the HDDs near the wall opposite the motherboard. A bit more compact.

Lsv
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Re: Design idea for silent mATX case

Post by Lsv » Mon Dec 12, 2011 5:58 pm

They look like badass rock climbing hard drives. I'm all for that hanging crazyness :)

silentg
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Re: Design idea for silent mATX case

Post by silentg » Wed Dec 21, 2011 3:45 pm

Originally this design was just an idea and I wasn't sure what I would like to do with it. Then I turned this into a challenge and on the next weekend I ordered new computer parts and started working with the case. Fortunately I was able to use a small workshop for free where I could built the wooden frame.
In the beginning of the week I got the computer parts and started putting things together. Then I was very glad to see how well everything fitted. Actually my old GPU (Sparkle 7900GS passive) didn't fit with mATX board because the CPU heatsink was on the way but this was not a big issue. Got a secondhand 8600GT passive instead.
One of my biggest fear was mounting of the PSU. Since I also realized that 4x 140mm fans would make the case too large I went with the 120mm ones that I already had. Now I was almost certain that I would need to put PSU on top. But instead I was able to fit it right next to the CPU HS :D
After I got everything working I noticed that video card wasn't very securely mounted when it was just sitting on the mobo. I got an old case and then I was able to cut out a part of motherboard tray and install it to the wooden frame.

Anyway, enough with the talk, here are some pictures:

Image

So fans are also placed on the top of the HDDs which is different from the original design. The final dimensions of this frame are 299x299x580mm

And here is a list of parts that I used:
Intel G530 - 35.30 €
Intel DH67BL - 74.00 €
2x Corsair DDR 4GB - 31.40 €
Cooler Master HYPER 212 - 28.90 €
Crucial M4 128GB - 170.50 €
Seasonic X-400 - 119.90 €

Frame: pine slats + glue + screws + hooks + elastic cord - 22€

Parts I used from previous build:
3x 2TB + 1TB HDD (WD green)
4x 120mm Nexus fans with fanmate

Now I'm waiting for 22nm CPUs and 28nm GPUs because I'm only keeping G530 temporarily.
But this is really surprising how cool G530 runs. All 4 fans are running minimal speed with fanmate at ~450rpm. Even with the full load the heatsink gets barely warm.
The loudest parts of this build are HDDs that are still audible.

So far I'm very happy how everything has turned out so far. I've been running it for over a week without issues. But as you can see this build is not really finished. At the moment this is just a frame. I would also like to cover it with something.. But I'm not sure with what so I open to suggestions.

silentg
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Re: Design idea for silent mATX case

Post by silentg » Thu Jan 05, 2012 8:20 am

So no suggestion of what material I should use for covering the frame? I already tried with corrugated cardboard but it didn't really improve the acoustics. HDD's are still audible.
I could also try with a thicker cardboard. But in addition the cardboard itself should be painted or covered with something so it would be more aesthetically pleasing.

There are 2 additional things that I really haven't though over:
Grounding/static electricity - should the MB have separate grounding with PSU? And what about HDDs?

Dust filter - as long as I keep it as frame I will clearly see the dust and could easily clean it. But once I will have the cover on I would prefer to have some kind of dust filter in the bottom. But from where I'm able to get a 250 x 250 mm dust filter?

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Re: Design idea for silent mATX case

Post by CA_Steve » Thu Jan 05, 2012 11:57 am

Ok, that's pretty wild. :)

Consider getting some soft rubber feet to isolate the wood frame from your wood floor. Or maybe thick felt furniture pads will work..

One of the favorite ways to reduce the lower frequencies (eg: HDD vibration) has been to add mass loaded vinyl to the inside of a case. You could get a box of vinyl tiles and use them to cover your frame...it won't have the same level of density, but think of all the styles!

Open celled foam is used to dampen higher frequencies. You can glue it to the backside of the vinyl.

silentg
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Re: Design idea for silent mATX case

Post by silentg » Thu Jan 05, 2012 1:14 pm

I'm not sure if I need a lot of extra dampening. When building this case I was secretly hoping it would be almost inaudible. At the moment it is still very quiet so I'm not complaining.
Since HDDs are suspended there is no vibration. I believe the motors inside HDDs are the main source of noise. And to me it sounds like more of high frequencies noise.

But if needed I can also run this in 0db mode. I'll just need to unplug 2 sata power cables from PSU and disconnect fanmate. G530 can easily be run in passive under full load while the cpu temp didn't rise above 60C.

But coming back to material vinyl seems like a crazy idea. Has anyone used it in the case mods before?
Another crazy idea I had would involve LEDs and pieces from shattered tempered glass but this might turn out to be too complicated. Also generally I'd avoid any leds and windows so I'm not sure why I'm even considering this.

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Re: Design idea for silent mATX case

Post by MikeC » Thu Jan 05, 2012 3:21 pm

So... it works fine now & the noise level is OK?

In that case, putting a thick skin around it will only make the noise worse unless that skin is really solid. Why worse? Because the air in any enclosed space (even partially enclosed) has resonances which will make some of the noise more audible. 50~300 Hz is a pretty typical range of fundamental resonant frequencies for a box of that volume. And that's a very audible range.

Rather than anything solid, I suggest a skin of cloth. Maybe speaker cloth (which is nothing but stretchy knit poly). Just wrap it around, and staple it along one of the vertical corner posts, make that face the wall corner.

As for any whining noise from HDDs, before you try any "solutions" just make sure of the noise source.

ces
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Re: Design idea for silent mATX case

Post by ces » Thu Jan 05, 2012 5:17 pm

See NoiseMagic NoVibes for handling the hard drive problem:
viewtopic.php?p=536315#p536315

flemeister
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Re: Design idea for silent mATX case

Post by flemeister » Fri Jan 06, 2012 2:20 am

You could enclose each hard drive in silencing enclosures such as the Scythe Quiet Drive, Nexus Drive-A-Way or GUP Smart Drive. And then suspend each of them.

http://www.youtube.com/watch?v=DkAAgquVmbk
http://www.youtube.com/watch?v=QVePQSY4JGU
http://www.youtube.com/watch?v=0dp9-k6aV3k

Not sure how a custom enclosure for all four of the drives together would go, since you won't have a fan to cool them. Maybe a box with an offset intake vent? Here's a similar concept:

http://www.youtube.com/watch?v=-5vvtt_vwgo

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Re: Design idea for silent mATX case

Post by CA_Steve » Fri Jan 06, 2012 4:50 pm

MikeC wrote:Rather than anything solid, I suggest a skin of cloth. Maybe speaker cloth (which is nothing but stretchy knit poly).
If there is air flow through the cloth, won't it become a dust magnet? Upside is having a really large air filter, downside is vacuuming/cleaning the cloth.

Tetreb
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Re: Design idea for silent mATX case

Post by Tetreb » Fri Jan 06, 2012 5:13 pm

The dust wouldn't be as visible on gray cloth maybe.
I've had mostly problems with higher pitched resonaces. The wavelength of a standing wave inside a say 5" space is 1350Hz. That's what I can hear inside my case easily, which is internally about 5" wide.
Lower pitched vibrations come from the fans when turning over 1000RPM or when there is a resonance below.
Since you're going DIY, an outer shell made of acoustically absorbing foam could help.
Last edited by Tetreb on Fri Jan 06, 2012 5:43 pm, edited 2 times in total.

MikeC
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Re: Design idea for silent mATX case

Post by MikeC » Fri Jan 06, 2012 5:25 pm

CA_Steve wrote:If there is air flow through the cloth, won't it become a dust magnet? Upside is having a really large air filter, downside is vacuuming/cleaning the cloth.
I doubt this would happen because the cloth has more impedance than the open ends on top and bottom, so the air will naturally flow through those areas rather than the cloth. A cap of some kind is needed at the top, with perhaps a 2" gap all around just below it. Same ~2" gap at the bottom.

Actually, come to think of it, a tighter weave cloth or one that's thicker might work better, with less audio transparency & more absorption.

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Re: Design idea for silent mATX case

Post by CA_Steve » Fri Jan 06, 2012 8:41 pm

Use drapes! With a tiny pull string so you can give PC component viewings.

Sorry - friday night. Alcohol might have been involved.

+1 on using heavier cloth as a sound dampener/kill reflections. Especially as the PC is up against a wall/hardwood floor.

silentg
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Re: Design idea for silent mATX case

Post by silentg » Sun Jan 08, 2012 10:36 am

Thanks for the suggestions. Using some kind of cloth could be quite interesting option. At first I suspected that cloth won't suit very well, because I want to keep the airflow more directional. Meaning that the air should escape after it has passed CPU/GPU heatsinks. Remember that both CPU and GPU will be replaced with more powerful ones that will produce more heat. Most probably I will get i5 3450 and Radeon HD 77x0 once these will be released. But the power consumption of these should still be quite low. But there are some many different types of cloth in varieties of colors... It would be too difficult to pick one :)

But coming back to noise, the system is still very quiet. A single WD20EARS should be <14 dB. Now with four drives I guessing the noise might be 15-17 dB?
So I won't be doing anything with the HDDs themselves to make these more quiet.

But what I happen to get was some leftover wallpaper that has very interesting texture. So got thick cardboard (from the casing of previous PC case) and made a panel by gluing the wallpaper on:
Image

So far I have only made one panel too see how it would look. But it was very time consuming process. And the glue made the cardboard soft and it got slightly bent. I had the keep it under a pressure to make it straight again. Most probably gluing wasn't even necessary at all. I could have just taped the edges of the wallpaper on the other side of the panel.

Now I'm not 100% sure if I should make 3 additional panels form this wallpaper or maybe try some other materials like cloth..

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Re: Design idea for silent mATX case

Post by MikeC » Sun Jan 08, 2012 10:54 am

Like I said, any surrounding skin that is not acoustically transparent or extremely absorbent will cause lower frequency "box" resonances that will probably exacerbate the noise of your fans and HDDs -- they make noises in the right frequency range. Even cardboard is reflective enough that such resonances will occur (think, for example, of a cardboard tube or box).

If you wrap the cloth around the sides but leave a 1-2" gap all around the top, with a cap of something more solid like wood board, there would be no impedance whatsoever of the air flowing up & out.

silentg
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Re: Design idea for silent mATX case

Post by silentg » Sun Jan 08, 2012 11:32 am

MikeC , you might be right that the outer skin could cause resonance but I don't think it will be significant. At the moment I just tried covering it with some cardboard and it somehow made the noise more smooth. I believe it was also slightly quieter but it was hard to tell..

Anyhow I still might consider using some kind of cloth. But in addition to speaker type cloth would there be any other types of cloth that you would recommend?

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Re: Design idea for silent mATX case

Post by xan_user » Sun Jan 08, 2012 11:43 am

maybe thick foam sheeting? like stereo/TV's are packaged in..

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Re: Design idea for silent mATX case

Post by MikeC » Sun Jan 08, 2012 11:54 am

silentg wrote:MikeC , you might be right that the outer skin could cause resonance but I don't think it will be significant. At the moment I just tried covering it with some cardboard and it somehow made the noise more smooth. I believe it was also slightly quieter but it was hard to tell..

Anyhow I still might consider using some kind of cloth. But in addition to speaker type cloth would there be any other types of cloth that you would recommend?
I retract my recommendation on spkr cloth. Better something heavier, thicker, more absorbent. Even a cheap rug -- like those cheap woven Ikea rugs (from India, I think) -- http://www.ikea.com/us/en/catalog/products/30211360/

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Re: Design idea for silent mATX case

Post by CA_Steve » Sun Jan 08, 2012 2:48 pm

Or a thick window curtain/drape.

edh
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Re: Design idea for silent mATX case

Post by edh » Sat Jan 14, 2012 5:57 am

How about bubble wrap? Includes a layer of trapped air for isolation. No good for thermal conduction but thats what the fans are there for.

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Re: Design idea for silent mATX case

Post by ntavlas » Sat Jan 14, 2012 6:39 am

I like the idea of dressing it with cloth. It`s probably one of the best solutions regarding acoustics but I mostly like it because it would end up looking quite original.

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Re: Design idea for silent mATX case

Post by MikeC » Sat Jan 14, 2012 7:54 am

ntavlas wrote:I like the idea of dressing it with cloth. It`s probably one of the best solutions regarding acoustics but I mostly like it because it would end up looking quite original.
A bit like a tower speaker... depending on the kind of fabric used.

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Re: Design idea for silent mATX case

Post by ntavlas » Sun Jan 15, 2012 2:01 am

A bit like a tower speaker... depending on the kind of fabric used.
What comes to mind is vintage speakers where the fabric often had stripes or other simple patterns.

Image

Using a fabric cover could involve some extra work though. Some sort of supporting structure like a wooden frame would be needed, to keep the fabric uniformly stretched and to protect from wear and tear.

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