New Case design, fan config, comments

LaidbackluxLaidbacklux New Haven
edited June 2003 in Hardware
I am working on a case, outside 1/2" red oak, inside diamond plate aluminum, and I was originally going to have a 172 rotron intake and a 172 rotron exhaust (both undervolted to push about 150cfm each). But then the whole series/parallel thing came up (see fan series/parellel...thread) and I redesigned to have two rotrons as intake.

Instead of having front intake, i am designing a horizontal divide about 10cm from the bottom of the case where I will put two fans blowing air upward (with a sandwiched HD inbetween). Vents on both sides of the case (below the divide) will let air in and 3 vents on the rear will serve as exhaust. The bottom chamber will be divided in half so that the fans will won't be drawing from the same air source. The intake vents area is approx 392 sq cm. The rotron fans have a combined open area of about 353 sq cm and the exhaust vents and psu exhaust add up to about 423 sq cm. The intake will be filtered but other than that i am hoping that the equal open areas will reduce any static pressure effects caused by only having intake fans. Now the case is wide, wide enough so that i put my psu on its side to the side of the pci slots. Its an antec true usually pumping no more than 30cfm and has a 92 intake and an 80mm exhaust, I am hoping that the minimal draw will ensure air flow over the non-oc'ed video card. AIr flow should be straight up with the positive pressure pushing air up and out toward the top of the rear. Positive cases are not that common and dead air space is I guess the biggest drawback, but please take a look at how i configured everything and let me know if this would work/what might work better.

The other thing to consider is that with a lot of open areas, sound will easily escape. The case is thick wood, the rotrons are supposed to be quiet when undervolted, the hard drive will be sandwiched, and the cpu fan is a papst, I may even splurge on some sound absorbing material, but is there any material i can cover the vents with that is sound absorbent yet still porous?

Any and all comments are appreciated and welcome. :)

Posted are a back view, an inside side view and a top down view of the horizontal divide. The vents are in the shape of a PG logo (perpetual groove, check'em out).

Comments

  • dNA3DdNA3D Brunei
    edited June 2003
    Whoaa!! Why don't you just go watercooling/phase change cooling. That way you'll be able to sleep.
  • EnverexEnverex Worcester, UK Icrontian
    edited June 2003
    I agree with dNA, if you are going to go through that much effort and have that many fans, I would go WC would be alot quieter and would pay off better.

    NS
  • LaidbackluxLaidbacklux New Haven
    edited June 2003
    I am seriously considering watercooling, just don't want to spend $200 plus for it. The rotrons are near silent when undervolted, as is the papst cpu fan. The noise can escape but there's not that much noise to begin with. Just a note in case i was unclear, there is space for fans on the rear but no fans will go there, they are just vents (using fan size dimensions will make finding premade filters easier...don't want gaping holes in the back).

    For the effort, watercooling will need maybe 2 or 3 less cutouts but would cost way more. Better cooling but i'm going for quiet not OC. The case is being built from scrath either way, in other words, effort is not really a reason for me not to use a fan solution. Noise level is really the currency here, i know water cooling is quiet but its not silent, a passively cooled water system would with be immensely expensive or require out of case solutions that I don't really want.
    So the 2 options would be the pictured above option with 3 fans (just the 2 rotrons and the cpu) all very quiet or the watercooling with a quiet fan and a quiet pump and an empty wallet. I am weighing both options, how loud do you think the above design would be? and can anyone suggest a water cooling solution, quietness over effectiveness, and on the cheap side?

    Thanks
  • dydxdydx Cymru, UK
    edited June 2003
    Water cooling need not be expensive.

    You can water cool for as little as $50. Unaclockr from #athlon wrote an article somwhere on watercooling done cheap.

    Ill dig arround and see if I can find it for you.

    Youll get better cooling performance, with less noise this way.


    mD
  • Geeky1Geeky1 University of the Pacific (Stockton, CA, USA)
    edited June 2003
    What exactly are you hoping to accomplish- absolute silence, or just a computer that's very quiet? There's absolutely no way you'll get a silent computer using air cooling. You can get pretty close, but any time air moves and it hits something, it's gonna make some noise...

    I WAS going to try recording one of the rotrons @ 12v, but guess what? The mic wouldn't pick it up from ~2" away... all I got was wind noise... They aren't silent, but they're quiet. Not nearly as quiet as an 80mm Vantec stealth (I have to hold the vantec up to my ear to hear it easily. The rotron I can hear across the room) but they're nowhere near as loud as a Delta
  • Geeky1Geeky1 University of the Pacific (Stockton, CA, USA)
    edited June 2003
    What exactly are you hoping to accomplish- absolute silence, or just a computer that's very quiet? There's absolutely no way you'll get a silent computer using air cooling. You can get pretty close, but any time air moves and it hits something, it's gonna make some noise...

    I WAS going to try recording one of the rotrons @ 12v, but guess what? The mic wouldn't pick it up from ~2" away... all I got was wind noise... They aren't silent, but they're quiet. Not nearly as quiet as an 80mm Vantec stealth (I have to hold the vantec up to my ear to hear it easily. The rotron I can hear across the room) but they're nowhere near as loud as a Delta 8k rpm fan either. I'd guesstimate they're around 35dba. However, they produce a very low frequency sound (think of one of those oscillating ac fans on low) so they aren't nearly as irritating as the smaller, higher-pitched fans you normally see in computers...

    you might try buying one of them from bgmicro and hooking it up to your computer to see if it's too noisy or not before you put all the work into building the case... you'll need some wire or something to hook it up tho, since it doesn't have a standard 4-pin molex connector (I just soldered some on...)

    As for the case itself, there are a couple issues that I see that may be a problem...

    1. Bottom intake fans are probably not going to be as effective as front intake fans because a good amount of the air is going to slam into the PCI/AGP devices and so it won't ever reach the cpu... ideally, the fans would blow air between the pci slots, either by mounting them above the motherboard, or by mounting them in front of the motherboard. Unfortunately, this has the side effect of adding noise, since the fans have a direct path to the room... Have you considered putting the fans in front of the motherboard, inside the case, and ducting them to the bottom of the case? That way you'll stop most of the noise, and get better cooling.

    2. You're gonna hate yourself for putting that PS there at some point. I'd put it either under or over the motherboard.

    3. What hard drive do you have? I don't know how you plan to enclose it, but any modern hard drive would be better off with some kind of airflow across it. Hell, my 4200rpm laptop hard drive gets hot after extended periods of use (e.g. a defrag, a big download, etc.) 5400rpm drives can probably get away without active cooling, but for 7200rpm+ drives, I'd be much more comfortable with some kind of fan blowing across it...
  • Geeky1Geeky1 University of the Pacific (Stockton, CA, USA)
    edited June 2003
    Gah! stupid keyboard :(

    anyhow, those are my ideas...
  • LaidbackluxLaidbacklux New Haven
    edited June 2003
    Thanks Geeky, helpful as usual, to answer some of your questions in reverse order.

    3. I have a Western Digital 7200 Special Edition, its the loudest thing in my computer at the moment. Its loud and outputs 7.8watts of heat. I saw several links to DIY sandwiches that resulted in a quieter and cooler HD (2 aluminum plates and paddining on the sides). The original setup (pictured above) has it getting decent airflow as it it between two fans(be it indirect flow).
    2. The mobo is removeable (pcmods sells a lian li tray). So hopefully the psu won't really get in the way of sliding the tray out. Prelim measurements suggest it would not.
    1. Ducting is a good idea, working on a modified design. But the original design has the two bottom fans far enough in front to just catch the corner of the pci and psu (see divide view) and I was hoping this would not be too disruptive, maybe even put some plastic to redirect to make flow better.

    My goal here is quiet as possible, my pc is too loud for me right now with a 120papst a 120 Panaflo L, a 92 zalman at 7V, and that loud WD HD. Case temps are about 1-2C above ambient, CPU about 19-21C over case. Since I am building a new case I thought i could take advantage of the larger more efficient fans and get better air flow from them, keeping the system quieter and cooler.

    Geeky, if i could request one more thing, a comparison between the rotrons @12v (or lower) and a 120 panaflo L or 120 papst fgl. That would be very helpful.

    Thanks again
  • Geeky1Geeky1 University of the Pacific (Stockton, CA, USA)
    edited June 2003
    Thanks. No problem. I just ran my only Papst (a 120x30mm 4312L) back-to-back w/one of the rotrons, and the Papst is quieter- it's essentially silent from a few feet away, while the rotron produces a hum which is audible but generally blends into the background noise of my room (aquarium, windows open, etc.) pretty well... it's still noticeable, but I don't find it irritating...

    I was just looking @ the original design again, and I think you're probably right- the PCI cards/PSU wouldn't be too big of a deal given the size of the fan in question. I'm not sure you need (or would really benefit) from that 2nd fan (the one closest to the front of the case) but the only way to tell for sure is to experiment with it...
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