Isolating stuff with foam

Enclosures and acoustic damping to help quiet them.

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tm
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Isolating stuff with foam

Post by tm » Mon Jan 06, 2003 11:44 am

I recently picked up some foam strips (used for windows normally, I think), and I was thinking of putting the stuff to use in isolating the P/S from the case, or at least have something absorb vibrations from the P/S fan. I was also thinking of lining foam where the panels come in contact with the case frame.

On second thought, for the P/S fan vibrations, I can remount the P/S fan with fan isolators and get the same benefit. But I can do the foam too! I'm wondering what people's experiences are with using dampening materials to absorb vibrations at the interfaces of things like the panels and the case frame or the P/S and its mounting brackets inside the case.

Any thoughts? Is this a useless waste of time? Is this something only for the truly obsessive? Has anyone actually bothered to do this? :)

Gandalf
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Post by Gandalf » Mon Jan 06, 2003 12:08 pm

I personally wouldn't put foam or anything in my PSU, there's already not a lot of space there for the air to move and it does get pretty hot there. If you're willing to try it feel free to do so and let us know whether it burnt or not though :P.

Putting foam on the spots where the panels are mounted on the frame would probably do away with quite a lot of vibrations, but I'm wondering how on earth you'll pull that off without your panels sticking out of your case :?

tm
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Post by tm » Mon Jan 06, 2003 12:21 pm

Gandalf wrote:I personally wouldn't put foam or anything in my PSU, there's already not a lot of space there for the air to move and it does get pretty hot there. If you're willing to try it feel free to do so and let us know whether it burnt or not though :P.
I guess I wasn't clear. I would not put foam IN the PSU, but on the little "shelves" and other places the PSU comes into contact with the case. It wouldn't be a lot of foam, I think, and I would be careful not to block any vents. I know many people have replaced their PSU fans, but have any used fan isolators when they did the replacement?
Gandalf wrote:Putting foam on the spots where the panels are mounted on the frame would probably do away with quite a lot of vibrations, but I'm wondering how on earth you'll pull that off without your panels sticking out of your case :?
Heh. I may have to use thinner slices of foam overall, though I'm not sure how to handle the "latches" (ie, where little "hooks" on the panel latch into slots on the case) or the grooves on the panel that slide onto the case. It will require some more thinking and looking carefully at the way the panel interfaces with the case :) The PSU-case contacts are also going to be tight, probably tighter than the panel-case contacts. I might have to use a pretty low density foam that can squeeze into these tight spaces. I'll try it out this weekend when I get a spare moment.

AlexHu
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Re: Isolating stuff with foam

Post by AlexHu » Mon Jan 06, 2003 6:32 pm

tm wrote:Any thoughts? Is this a useless waste of time? Is this something only for the truly obsessive? Has anyone actually bothered to do this? :)
I did just that, with the window foam strip. It seems to remove a little bit of vibration. Not much, but I FEEL better with the strip that.

Asmordean
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Post by Asmordean » Mon Jan 06, 2003 8:17 pm

Back when I first started trying to go silent I did the same thing. I've discovered that it was a waste of my time.

Why? Yes, fans do vibrate but the vibration of a fan with good bearings and balance produces so little noise versus the airflow that you would have a hard time hearing any change. A HDD will overpower any gains.

If your fan is vibrating to the point that you need to isolate it, then I suggest you get a new fan and undervolt it a little.

seishino
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Isolating vibrations vs encouraging them

Post by seishino » Tue Jan 07, 2003 10:20 am

One of my first experiments in silencing was to isolate the fans in the case with layers of double-sided tape and thick, soft foam. The results were disasterous. The foam wasn't firm enough to keep the fans held in place, and they began to oscillate rapidly in place. The resultant turbulance made the fans quite loud and annoying.

If you are just isolating a full-power fan without getting a balanced high-quality one and undervolting, then you may be asking for trouble...

-C

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Post by powergyoza » Tue Jan 07, 2003 11:12 am

Here's a previous thread that dealt with your concerns: http://forums.silentpcreview.com/forums ... highlight=

And another one: http://forums.silentpcreview.com/forums ... =2412#4214

Happy decoupling!

Destron
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Post by Destron » Wed Jan 08, 2003 9:52 pm

I would not recommend going to the effort for the reasons posted above, and because the rubber grommets you say you might place between the fan and the power supply (on the inside) will reduce vibrations enough that any more foam between the PSU and the case would be un-useful.

Think of the law of diminishing returns.

Ralf Hutter
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Post by Ralf Hutter » Thu Jan 09, 2003 5:21 am

I wouldn't recommend putting foam inside a case at all. All the foam I've ever worked with tends to break down and turn to powder when it's in proximity to heat and ozone (from electricity). I work around noisy machinery and have seen many different methods of noise-control during the last twenty years. Any of them that involved foam worked initially but didn't last long during actual use.

My 2 cents, FWIW.

spudston
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Post by spudston » Mon Jan 20, 2003 1:13 pm

Ralf, how long in your experience did the foam last? I've just insulated my HDD from my case using foam and the noise reduction is amazing (the screwless case clamps did not hold it very securely so it vibrated). I work in construction and a diesel generator on my site uses foam sound insulation, so I wonder if there is special heat resisistant foam used there. I know loudspeaker foam surrounds rot away after about 15 years but no way will I have my computer that long! :)

Ralf Hutter
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Post by Ralf Hutter » Tue Jan 21, 2003 5:07 am

spudston wrote:Ralf, how long in your experience did the foam last? I've just insulated my HDD from my case using foam and the noise reduction is amazing (the screwless case clamps did not hold it very securely so it vibrated). I work in construction and a diesel generator on my site uses foam sound insulation, so I wonder if there is special heat resisistant foam used there. I know loudspeaker foam surrounds rot away after about 15 years but no way will I have my computer that long! :)
It depends on the enviornment that the foam is in. Heat, ozone and oil tend to break it down faster.The foam in our electrical cabinets at work starts to get noticeably harder (it loses it's resiliency) after just 6 months and starts falling apart after a year or so. I have some foam on my walls at home that I use for acoustical purposes that lasts for a few years before it starts falling apart.

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