Damping Panels

Kizz · Post by **Kizz** » Fri Oct 28, 2005 3:58 am

I'm thinking about making a damping panel for behind my case to absorb some of the noise, as it blows out right onto a concrete wall - not great for absorbing sounds - as such I took a look around to see what material I have at hand - and found 3 likely candidates, as well as a bunch of ~3mm board to use as a base -

-Some pretty soft ~1" blue foam, that compresses to about 0.5" when it's squidged hard

-A bunch of old carpet, not really that thick but with most of the fibre still on it

-A whole load of rubbery carpet underlay with rounded ridges - seems pretty thick

I'm thinking that would be kinda the order they would go from best-last for sound absorbtion, just wondering which would be the best, and if they would affect heat dissipation at all (maybe stick a layer of aluminium foil behind to reflect heat?). Or maybe use a mixture such as carpet-underlay-foil sandwich?

Thanks

brickout1 · Post by **brickout1** » Fri Oct 28, 2005 4:31 am

Heat dissipation won't be a problem behind your case since all of the surface area involved has access to air at ambient room temperature, so don't mess with the foil. I also wouldn't mess with the rubbery stuff since dense material is usually used to stop vibrational noise, and that won't be a problem on the concrete. I would just use the foam, as all that is reflecting off the wall is sound energy, and the 1" thick soft foam would be the best IMO for stopping most of that. You can also try turning the pc slightly so that the sound energy is directed at the wall at an angle, which will increase the distance it has to travel through the foam to reflect back into the room.

Might also want to try using two layers of the foam on the wall...Just my $.02.

Good luck!

Kizz · Post by **Kizz** » Fri Oct 28, 2005 6:25 am

Alright great thanks. The best methodology will probably be subjective anyway, so I'll create a panel with one layer of foam, then add another see if it has any noticeable benefit. Hell, I might even have enough to make some side ones too.

hofffam · Post by **hofffam** » Fri Oct 28, 2005 6:47 am

I don't understand your question about heat dissipation. Do you want the material to absorb heat or reflect it? Or is the concrete warm and you want to insulate it.

The don't know about that blue foam. How good it is depends on the size of the pores. If it looks like the kind of foam they sell for loudspeaker use (like this: http://www.partsexpress.com/pe/pshowdet ... ak=260-515 it might be good.

I agree the rubber stuff doesn't sound promising. It is probably too reflective.

One way to test it is to use your audio system. Place a piece of material at a 45 degree angle in front of a loudspeaker. Play some music at a moderate level. Listen from the side (as if the foam or carpet were a reflector). Don't change the volume and pick whichever material is quieter. I wouldn't be surprised if the carpet ended up best but it obviously depends on the pile/design of the carpet.

Post by **Ralf Hutter** » Fri Oct 28, 2005 6:51 am

I've been using some 2" Sonex behind my case for years. It's not a "be-all-end-all" solution, but it's cheap and easy and does cut down a bit on the noise that reflects off the back wall.

Kizz · Post by **Kizz** » Fri Oct 28, 2005 7:00 am

Well it has smallish pores, and looks to be a better sound absorber than the carpet (which is pretty flimsy anyways) so I'm going ahead and fabricating a panel - I'll give it a roll and see how it fares, maybe even create some form of an enclosure since I don't have much to do and the weather sucks out.