Crazy? or not...

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rafezetter
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Joined: Sat Feb 09, 2013 6:51 am

Crazy? or not...

Post by rafezetter » Sat Feb 09, 2013 8:02 am

Hi - first post of first visit, - I've been thinking about building a pc enclosure or a wooden framed PC as part of a dedicated desk build for a while (to build it once and allow space for any and all possible PC builds after - even with these crazy sized graphics cards) and I've been looking at various ways to deaden the sound and I had a bit of a crazy idea.

Obviously for many of the exposed wooden parts where nothing is attached i'd use some form of acoustic deadening material - yet to be fully decided on as budget is tight..

But for some of the other areas like the backer for the mobo and HD / DVD drive enclosures and other fiddly places I had a bit of a notion - painting those areas with rubberised floor paint, the non slip kinda stuff put in work areas, which might reduce the resonance of the wood and provide a bit more sound deadening.

is that a crazy idea or anyone think it might have some sound (scuse pun) basis for application?

also as this thing will be as tall as a normal desk (28inches or 700mm give or take) - because it will form one side of the desk support - should the larger side sheets have some form of bracing attached to stiffen them and reduce harmonic resonance there too?

If anyone wants to throw in any ideas or suggestions, or tested/proven techniques please feel free - anything to narrow down the list of possible build materials, sound deadening options and all manner of things I've been seeing over the last year or so. Any threads here or elsewhere you can point me to for any possible idea or advice is also welcome - I only want to build this once and would hate to miss something once I have. The woodworking I do a lot of so that isn't a problem.

I'm using this thread I saw ages ago as the basis for this idea:

http://www.silentpcreview.com/article237-page1.html

I'm not trying for silent, silent, but reduce it enough so that when my GPU fans spin up to max it doesn't bleed through my over ear headphones - and hopefully gives me the option to ramp up the case fans with a controller to max - or close to it, when gaming to ease the CPU and GPU a little.

rafezetter
Posts: 10
Joined: Sat Feb 09, 2013 6:51 am

Re: Crazy? or not...

Post by rafezetter » Sun Feb 10, 2013 6:30 am

Another idea..

I saw this posted here in '04 in a reply to a frequency question and wondered if anyone could add any info on things like thickness required etc?

"Nothing will stop noise below ~200Hz except things like concrete"

I ask as I have used a roofing tile that looks like slate and is about 5mm thick, but is made of concrete, could this be a possible alternative to a thick slab of MDF as a mass dampener?

Edit:

I've found this info

MDF approx 700 kg/m^3
Concrete approx 2400 kg/m^3

being that concrete is roughly x3 denser, it might be feasible that a section constructed of 3 x 5mm concrete tiles with a silicone washer in between them provides the same mass dampening as 45mm of MDF.

I wonder if there's any sound engineer types here that might be able to advise on this?

mercyfull_fate
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Re: Crazy? or not...

Post by mercyfull_fate » Sun Feb 10, 2013 10:15 am

i'm a bit short in time so i will say it a bit simple, but basicly is you want to stop sound from going trough a panel/wall, you want it as have but as flexibel as posible. concrete works because of its weight, brick is a bit worse because of less weight with the same stiffness. 2 brick walls with air space between them works very well because you double the weight, but not the stifness. But if you use 2 gypsem boards with lead between them it works just ass well as the 2 brick walls with air because it is very flexible and heavy.

and ass for frequencies:
higher frequencies are less bound by the before mentioned as it can pass easier through small holes, so for higher frequencies its more importent to minimize holes and increase absorption of the sound

xan_user
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Re: Crazy? or not...

Post by xan_user » Sun Feb 10, 2013 10:57 am

If anyone wants to throw in any ideas or suggestions, or tested/proven techniques please feel free
build with quiet components, and sound proofing is not necessarily. what video card? is there an aftermarket cooler that can fit it?
Last edited by xan_user on Mon Feb 11, 2013 9:12 am, edited 1 time in total.

rafezetter
Posts: 10
Joined: Sat Feb 09, 2013 6:51 am

Re: Crazy? or not...

Post by rafezetter » Sun Feb 10, 2013 6:04 pm

TY mercifull_fate - to answer you I intend to use a sealer - caulk or similar between each panel joint to seal any small gaps, and a letterbox draught excluder (http://www.amazon.co.uk/Internal-Letter ... 65&sr=8-13) at the back of the case for the wires to go into as the connectors will be inside, which might help reduce noise leakage out the back, although I'll also be putting some form of absorbancy there too.

For the graphics card currently it's a 560ti twin frozr 3 - with 2 small fans that are very effective if a lil loud under full load, but I'm trying to design either an enclosure OR a frame to attach the internal parts to without the need for a separate case inside that will last for many upgrades to come.

I have used quieter case fans instead of stock, but my plan is to use 3 200mm sidefans near the bottom and angled upwards that spin 700rpm for 110 CFM's that are facing the mobo for even better direct cooling instead of the front to back system, as my GPU fans already push UP instead of OUT, and my CPU cooler is also orientated UP to direct the flow out the top 140mm casefan.

Hopefully the angled UP and OUT the top venting will remove the issue of sound waves coming out the back of the enclosure and hitting the wall the desk is in front of.

I may also have it so that it vents UP into another chamber above (as there will be 7-8 inches of extra vertical space) that can be used for storage or something but also insulated for sound a bit.

I've considered water cooling, but I'm not all that comfortable with that idea yet..and as for immersing in mineral oil...YIKES!

fastturtle
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Re: Crazy? or not...

Post by fastturtle » Wed Apr 10, 2013 9:01 pm

I've been looking into this for a while and the one thing I've found is that isolation is pretty much the key to a quiet system. Using a standard size wood box - ensure that your mobo tray and such has as little contact with the case. This alone will drop 90 percent of the system noise. The next is high frequency sound as that attenuates quickly. Ensure good sealing of the box - a single 100 cfm fan behind a good filter should handle most if not all of the air flow needs (positive pressure design). The exaust area is where you'd run your cables into the box if needed using a scotch brite pad to handle the remaining high frequency sound. Don't forget to use a light baffel setup on the exhuast to help and you should be just about golden.

Wood itself is a very good material though I'd toss the MDF out the door. It's durability leaves lots to be desired and it's actually more costly then real wood for little to no gain. Right now, a basic 24inch wide by 36inch long Pine board (single piece) is less then what the same size MDF would cost and it looks much better. A pair of boards that size (no cutting needed) along with a set of 12-18 inch pine boards for the front/back and you've got almost everything needed for the case itself and I think you can go from here.

idbash
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Joined: Thu Jun 13, 2013 6:01 am

Re: Crazy? or not...

Post by idbash » Fri Jun 14, 2013 8:52 am

I feel there is a very big piece that is being missed with this, it is not about stopping sound from penetrating that you are going to need to worry about, it is reflection. All the aforementioned materials will stop a sound through reflection. IE, the soundwaves are still alive and well, and will keep bouncing until they run out of energy essentially, meaning that when they will bounce then out of all your exhaust ports and get to your ears again. Wood will keep most of the sound inside, but you need to then absorb that sound before it can reach you. Low frequencies are hard to absorb due to the sheer size of the wavelength. You could build a absorption tube for low frequencies, but they are big an annoying (everything bass trap in 1 page http://en.wikipedia.org/wiki/Bass_trap). That said, low frequencies are not the main concern as they are not as painful because ears lose low frequencies first, and mids-highs are the easiest to hear.

Now all that said, what you will most likely want to do on a budget is add some cheap foam (example, http://www.amazon.com/Auralex-Studiofoa ... ZH42S8YU3C) and add it inside the box in crossing patterns... this will trap the lo-mids to highs very well, which are the primary sounds coming out of the case.

As far as the bleed points go, make tunnels that lead to the exhaust points that have foam around the sides to trap as much of the sound before it leaves the case. I would also add a filter on the end of the tunnels that you can remove and clean as well as make it look nicer since taking your computer outside and blasting the dust out is not so easily done....

Finally, when you finish, POST PICS!

Biff Tannen
Posts: 1
Joined: Thu Sep 19, 2013 6:54 am

Re: Crazy? or not...

Post by Biff Tannen » Thu Sep 19, 2013 7:01 am

OR a frame to attach the internal parts to without the need for a separate case inside that will last for many upgrades to come
How would this be http://www.lian-li.com/en/dt_portfolio/pc-t60/ it is a test bench to mount a mobo an such.

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