[Advice needed]Wooden case build using the Silverstone RV03

Enclosures and acoustic damping to help quiet them.

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Peonforevah
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[Advice needed]Wooden case build using the Silverstone RV03

Post by Peonforevah » Sat Jan 14, 2012 11:15 am

Hello there,

I have been thinking for some time about building my own pc case (for gaming), I don't have the tools and skills required though. So I wanted to cut some corners using the RV03 case which I think is pretty slick airflow / heat management efficiency wise due to upwards airflow (90 degree rotated mobo) -> heat rises.

I have a great watercooling kit already which I don't want to throw away although you guys seem to love air cooling more. I use high wattage hardware so as silent as possible is the way I am going for.

The stuff I learned sound wise on this forum is trying little air restriction and indirect sound paths from the source. Since a picture can say more than 1000 words:

Image

The wood I'm going to use is MDF (20 mm thick) which is used in speakers alot, Isn't expensive and it's dead wood (it doesn't shrink or expand).

What do you think about the design? Soundpath wise, air restriction wise? What should I do about the Power Supply? Since I haven't designed an output hole yet. The harddisks and pump will be suspended by elastic.
I am using the Radiator as intake, many people say thats bad since you will get hot air inside your case. But I can't see that being bad, Thermodynamic wise the heat exchange will be the same. If I use the Rad as outtake it will suck in ''warm'' air so my CPU and GPU will be cooled less. So I think it's just about what priority you have (CPU+GPU vs Mosfets etc.). Or is my logic wrong?
The 180mm Air Penetrators from Silverstone are blowing straight up right now, won't it be better to put it under a slight angle facing the mobo? Instead of blowing way past the motherboard it will touch it more in my reasoning (Like the Silverstone FT03)
Using the optional fan for my harddisks like my picture shows?
Doors are in my opinion awesome, but I know doors always will have gaps. I don't like gaps! :D Any solutions for this? I don't like screws on the outside of my case.

More pics to give you the idea of my design:

Image
Image
Image


Any ideas? Spew it haha

Greetz,
Peon

MikeC
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Re: [Advice needed]Wooden case build using the Silverstone R

Post by MikeC » Sun Jan 15, 2012 11:19 am

Nice drawings, decent concept. But something is unclear to me. When you say -- "So I wanted to cut some corners using the RV03 case" -- does that mean you want to replace the panels on a RV03 w/ wood? Or just use the RV03 case designs as a template for your own all-wood box?

Peonforevah
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Re: [Advice needed]Wooden case build using the Silverstone R

Post by Peonforevah » Sun Jan 15, 2012 2:27 pm

I really love the frame of the RV03, I hate the rest of it (visual design + plastic). So I'm not going to use the flimsy panels / front / top. I am replacing those all by wood. So this -> ''you want to replace the panels on a RV03 w/ wood''.

A friend of mine told me I shouldn't care about the air restriction and came up with an idea for total silence. Though it really makes the case enormous. (90 cm's tall lol)

Image

Purple = sound absorbing material

Image

The height of the airducts are 10 cm's, is that enough? (the minimum area which air can go through is 19.1*10= 191 cm^2 - for comparison, 1x 180 mm fan = 254 cm^2)

Thank you Mike for allowing my topic ^^

MikeC
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Re: [Advice needed]Wooden case build using the Silverstone R

Post by MikeC » Sun Jan 15, 2012 3:19 pm

OK, understood.

I actually built a huge 5/8" medite board box with tunnel in/out vents like yours, not as a PC case but as a cabinet to put a PC into. Very similar to your concept. It was built around a tubular steel frame, the thing weighed ~120 lbs. The PC I put in there was already quiet, probably not much over 20 dBA/1m.

The end result was virtual silence. The only thing that remained was the fundamental frequency of the fans that spun in there -- I think I may have had 2 or 3, one in the PSU running super slow, a couple buried in one of the tunnels. But this became a problem over time.

Why?

Without any white/pink noise to hide the fundamental tones of the fans, the noise became pure a tone -- like a note on a synth played continuously at very low level. Say 300Hz (or lower), at 15 dBA/1m, maybe less. This may have been exacerbated by the air resonance of the tunnels themselves. Still, very quiet right? Yeah but when it is the only sound, it somehow gets into your head & bounces around till you go nuts.

I abandoned the box in a few mos and went to a PC with slightly higher overall noise, but no tones, it was virtually all broadband sound -- ie, pink noise. I'm much happier with this. In fact, I often prefer the sound of completely unenclosed fans and HDDs over the same noise sources inside a case. The enclosed air in the case causes resonances which often have tonal elements, and those bother me much more than a low level whoosh. Hence my preference for a HTPC with components that sit on a board, completely open. When you get within a meter, it's easily audible, perhaps 16-18 dBA, but the overall noise signature is perfectly smooth, without any peaks (tonal sound). Most people have no idea this is in the TV stand. (Deep shelf dark colored, hard to see, not much to hear)

So my advise is to ditch the tunnels. Your first drawings will work better.

Peonforevah
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Re: [Advice needed]Wooden case build using the Silverstone R

Post by Peonforevah » Sun Jan 15, 2012 3:45 pm

Thanks for your advice! Is the wood needed at all then? The main reason I wanted to go with thick wood was for silence, but since you recommend having a pc out in the open I can just use the flimsy metal doors aswell, or thinner wood for the sake of originality. And alot of mesh to cause open air? Should I ditch the indirect soundpaths aswell?

Not having a case is what I have right now :p I don't like it haha, very hard to go on a LAN now and then.

According to your information this is what I have in mind right now:

My first picture but:
Thinner walls
Mesh for my power supply
Suspended HDD's / Pump
A gasoline like intake for easy filling loop
Intake / Outtake all around the case for less restriction (instead only rear)-> Fans can turn slower
Doors on hinges (which isn't sound / air proof)
I don't like the round design, I'll make the design square eventhough it weakens the feet.
I should keep the bottom -> top airflow right? Cause there are also fanholes for front -> rear. So I could combine...

Would this be the bomb?

MikeC
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Re: [Advice needed]Wooden case build using the Silverstone R

Post by MikeC » Sun Jan 15, 2012 4:01 pm

Well...

1) if you are going to replace the steel panels, go with something better, too thin a wood board will still want to vibrate, like the steel. I think 20mm medite will make the whole case so heavy you won't be going to any LAN parties unless you have a hulking sidekick. Maybe go with 15mm or lighter. Or marine plywood? (if it is lighter)

2) Not sure why you need a mesh for your PSU -- there is already a filter for the intake, no?

3) Looks like the HDDs might be low on airflow; you could add a little deflector inside that diverts some of the inflow from the bottom towards them instead of adding another fan under the HDDs. Takes very little fresh airflow to keep HDDs cool.

4) Keep the bottom-to-top airflow scheme, don't add any spurious holes, as this only diffuses the effectiveness of the airflow.

This would indeed be da bomb.

Peonforevah
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Re: [Advice needed]Wooden case build using the Silverstone R

Post by Peonforevah » Sun Jan 15, 2012 4:25 pm

MikeC wrote:Well...

1) if you are going to replace the steel panels, go with something better, too thin a wood board will still want to vibrate, like the steel. I think 20mm medite will make the whole case so heavy you won't be going to any LAN parties unless you have a hulking sidekick. Maybe go with 15mm or lighter. Or marine plywood? (if it is lighter)

2) Not sure why you need a mesh for your PSU -- there is already a filter for the intake, no?

3) Looks like the HDDs might be low on airflow; you could add a little deflector inside that diverts some of the inflow from the bottom towards them instead of adding another fan under the HDDs. Takes very little fresh airflow to keep HDDs cool.

4) Keep the bottom-to-top airflow scheme, don't add any spurious holes, as this only diffuses the effectiveness of the airflow.

This would indeed be da bomb.
1. Don't know much about plywood vs mdf, I read mdf was good sound dampener and cheap and easy to toy with. I just googled and it seems plywood is stronger and lighter. The few times I hassle a computer case 60 pounds in total is fine;)

2. The RV03 without mods has a meshpanel for the outtake of the power supply, my idea was to put the power supply further behind towards the ''cable door'' so that it can spew air against the main door which will then go up eventually (convection)

Image

3. deflector is a great idea. what do you think about angling the 180 mm fans towards the mobo and the one on the right slightly towards the hdd's?

Thanks for the advice Mike^^.

Peonforevah
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Re: [Advice needed]Wooden case build using the Silverstone R

Post by Peonforevah » Mon Jan 16, 2012 6:15 am

Hej Mike do you mind (if you have) posting some pictures of your baffle system which gave you tonal sounds because of the enclosed air? My friend didn't experience such thing and thought it completely silent. He assumes you didn't use sound absorbing material in your tunnels. So now I 'm curious :D

Greetings,
Peon

MikeC
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Re: [Advice needed]Wooden case build using the Silverstone R

Post by MikeC » Mon Jan 16, 2012 7:35 am

Peonforevah wrote:Hej Mike do you mind (if you have) posting some pictures of your baffle system which gave you tonal sounds because of the enclosed air? My friend didn't experience such thing and thought it completely silent. He assumes you didn't use sound absorbing material in your tunnels. So now I 'm curious :D
Of course I used damping materials!

You have to keep in mind that the little hum I referred to was extremely low in level. Anyone who visited my home office would remark on the extraordinary quiet in that room w/ the computer on. The general opin was that it was silent, inaudible.

It's only after I worked for many hours daily, many days weekly, and many months in a row in close proximity to the system that this little hum became annoying.

I didn't have all the measurement tools then that I do now, but I'd venture to say that if the system were to be measured for SPL and frequency spectrum in my anechoic chamber today, this would be the result:

1. before enclosure, the SPL would probably be 15~18 dBA/1m, with a broadband signature and perhaps a single narrow band peak of a couple dB, somewhere in the 120~300Hz range.
2. after enclosure, the SPL would probably be 10-13 dBA, with a broadband signature and perhaps a single narrow band peak at maybe 15-16 dB, somewhere in the 120~300Hz range.

The key here is the average broadband level. After enclosure, it dropped below the background level of my working room, which meant that the remaining peak was left standing by itself (subjectively speaking), and thus audible as a pure tone. Prior to enclosure, the broadband (white/pink) noise of air turbulence, which was audible above the background noise of the room, masked the peak enough so that it was not audible as a pure tone. Or perhaps the peak/tone developed as a result of the tunnel/enclosure resonances.

The issue with tunnels (any enclosed or semi-enclosed space) is that the air in them always has resonances. If you have any noise makers in them with output at or near those resonances, their noise will be exacerbated. So while the overall noise and measured SPL of a fan at 600rpm might drop by say 6 dB inside one of those tunnels, let's say it has a fundamental at 250 Hz which happens to coincide with a peak in the tunnel at that frequency. Then, while the damping material might bring the level of that fundamental down by a couple dB, the resonance might bring it back up by the same level. Now, with all the masking broadband noise no longer audible (because it is below your room ambient), that peak becomes a pure tone.

Ditto HDDs, btw, which have fundamentals at 90Hz (5400rpm) or 120Hz (7200rpm)... and secondary tones at multiples of those frequencies.

Peonforevah
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Re: [Advice needed]Wooden case build using the Silverstone R

Post by Peonforevah » Mon Jan 16, 2012 11:25 am

Thank you for the detailed explanation!:D

I am going to make the bottom and top modulair, so I can easily make ducts if I do want to try it and install them / remove them. Because maybe I still think my case is to loud without ducts and really curious to the results since my ears might not pick up the single spike of 18 dBA.

Has anyone ever tried magnets to keep casedoors / io panels locked? My case had a little magnet in it so I searched on the web, and they are cheap and seem safe to me as long as you use weak magnets and don't put them near the electronics. Any opinions about this / horror stories / good findings?:P

cordis
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Re: [Advice needed]Wooden case build using the Silverstone R

Post by cordis » Mon Jan 16, 2012 12:45 pm

I built myself a wooden case using the rotated orientation, but it was a full custom build, not using any existing case framework except for the motherboard tray. Here's the thread about it: viewtopic.php?f=14&t=61400
I haven't had any problems as far as resonance goes, the air paths are a fairly straight shot and have lots of turbulence causing bumps along the way, so I doubt a resonance could form. You might have one in a cavity that's clean that you're just using for moving air. As far as closing it up went, I used the brass clasp type things. They work fairly well, and I made sure that the damping material I put inside had a little more overlap than the doors. Magnets could hold them shut, but I'd be worried too much about my hard drives to try them. To get a good seal on the door, you'd want them to be strong. The rotated motherboard is really good for air cooling, not sure about how it will work with water. Good luck with it, anyway!

Peonforevah
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Re: [Advice needed]Wooden case build using the Silverstone R

Post by Peonforevah » Mon Jan 16, 2012 5:57 pm

Yes I agree, if the doors have to press the isolation material 1.2 kilos of force won't be enough. Stronger magnets won't be good for my harddrives, do you mean those clasps people use for the backyard door? :p haha thanks for the reaction ^^. I'm trying to find some '' push to release'' switch, don't know for what word to google though ;)

ps. that box is little! haha itx mobo, I've got to much stuff I want to fit :(

pps. if people wanna know here are the names for different kind of latches ''push to release /close'' etc.

http://www.southco.com/browse/concealed ... -7329.html
http://www.gripwell.com.sg/products/eng ... tches.html

hahaha I can't find the dutch word for it :D going nuts lol, soon I'll just have to import from the UK xD

cordis
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Re: [Advice needed]Wooden case build using the Silverstone R

Post by cordis » Tue Jan 17, 2012 1:12 am

No, the things I'm talking about are brass hasps like this: http://www.lowes.com/pd_311955-1277-890 ... facetInfo=
And hey, the box can hold a full size ATX motherboard. I have an overclocked i7 980x in it with a Noctua NH-D14 on it, and dual gtx 460s, and I'm upgrading it to dual 560 Ti's this weekend. Now if you're interested in a bigger box, I did a version in brass too, (here's the thread: viewtopic.php?f=14&t=59803&hilit=brass) it supports 8 slots, and hold 14 hard drives. Kinda huge though.

As far as the 'push to open' switches go, yeah, could work. We have some of those on some cabinets at the office, they seem to wear out and get harder to use. But you probably wouldn't open it that often, I suppose.

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