looking for guide/how to/or general advice on dampening

Enclosures and acoustic damping to help quiet them.

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aowen512
Posts: 104
Joined: Mon Jun 20, 2005 6:34 pm

looking for guide/how to/or general advice on dampening

Post by aowen512 » Fri May 05, 2006 7:57 am

questions

1) What are good/best materials for dampening?
1a) Will packaging foam that you usually get when you have something shipped work pretty well?
1b) If not, what is the bang for buck material I can buy?
2) How to correctly place the materials. Looking for a guide/how to place the materials in the best way to reduce noise. Pictures are a huge plus! Basically, am I to just cover every inch possible(not including intakes and parts)??

Anything you guys can throw my way would be awesome!

Thx

aowen512

Trunks
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Location: Baton Rouge, LA

Re: looking for guide/how to/or general advice on dampening

Post by Trunks » Fri May 05, 2006 1:10 pm

1.Depends on your case. I would say Acoustipac is great. But not cheap.
1a. I don’t know what that is, I normally get Styrofoam nuts or paper… they are all bad.
1b. Carpet pad foam.
2 over every surface that is not needed for ventilation.

aowen512
Posts: 104
Joined: Mon Jun 20, 2005 6:34 pm

Post by aowen512 » Fri May 05, 2006 3:21 pm

carpet pad foam, should i be going to lowes or menards or is there something online that you can give me a link to?

Trunks
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Location: Baton Rouge, LA

Post by Trunks » Fri May 05, 2006 3:38 pm

carpet pad
the lows near me has it for ~$0.65 per foot.
they will have several types. "Slab Rubber" type is the best.
Rebond Foam is very good too... for being cheap.

Felger Carbon
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Post by Felger Carbon » Sat May 06, 2006 3:22 am

The discussions on this topic appear to focus on only one type of noise reduction: that achieved(?) by lightweight foam, of the sort that lines the walls of high-end acoustic studios in very very thick layers.

While this obviously works in very very thick layers there isn't room for that in a computer case. I wonder whether stuff that's an inch thick or less (or much less) can really attenuate noise much. I won't say it doesn't because I haven't personally tried it.

What's absent from this topic (so far) is any consideration at all of mass loading, typified by Dynamat Extreme (DE) on one end and cutting up and gluing in pieces of vinyl flooring tile on the other end. I have tried DE and it works well for me. I have also used McMaster buna and DickBlick rubber blocks, which have their points.

Thick rubber blocks HDD whine by absorbing the sound as it tries to pass thru, and when bonded securely to the thin chassis sheet steel, prevents resonance and also serves one more vital function:

In a typical computer case, a vibrating HDD serves as the voice coil and the thin sheet steel serves as the loudspeaker cone. The combination works all too well to efficiently deliver acoustic noise that originates in the vibrating HDD. When DE (or other mass loading) is applied to the thin sheet steel, the efficiency of this defacto loudspeaker drops considerably, thus reducing the acoustic noise caused by the vibrating HDD.

My experiments with mass loading indicate that vibrating HDD noise can best be treated by applying mass loading to the motherboard support plate, inside the computer, while HDD whine and fan whine are best treated by applying mass loading to the skin of the computer, thus absorbing the sound as it tries to escape the computer cavity.

Let me repeat: I have not tried lightweight foam. It may well work very well indeed and I'm missing out on a very good thing. Or not. I can personally attest that mass loading works and works well.

Trunks
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Location: Baton Rouge, LA

Post by Trunks » Sat May 06, 2006 9:20 am

Felger Carbon wrote: ...Dynamat Extreme (DE) on one end and cutting up and gluing in pieces of vinyl flooring tile on the other end. ...
Let me repeat: I have not tried lightweight foam. It may well work very well indeed and I'm missing out on a very good thing. Or not. I can personally attest that mass loading works and works well.
I agree Dynamat Extreme works very well. It is also very expensive.
Carpet pad is fairly dense, it helps mass load if glued in place.
I would not say carpet pad, slab type or rebond type is the “bestâ€

Felger Carbon
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Post by Felger Carbon » Sat May 06, 2006 10:03 am

Trunks wrote:I agree Dynamat Extreme works very well. It is also very expensive.
Expense is relative. The 12 sq ft 2-door kit 10435 can be found online for $60 or less. That's enough to treat 3 chassis at $20 per chassis. Some folks here at SPCR think nothing of spending $40-$60 for an HDD enclosure that mostly heats one HDD.

As you say, it works well. A good workman is worth his pay. :D

krille
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Post by krille » Sat May 06, 2006 2:22 pm

So would Dynamat Extreme (DE) and Vinyl combo be superior to say Acousti Products AcoustiPack Deluxe V2? Or is it just "cheaper"?

(I already have some Nexus DampTek but in my other thread the consensus seemed to be AcoustiPack was better, so I'll use the Nexus Damptek for another rig and buy something better for my main computer I use the most.)

Accordingly, I'm also in the business of looking for noise reducing material/sheets/foam/whatever for my P180 SPCR I intend to buy. Cost isn't a big issue (AcoustiPack is 100% fine, costlier stuff would indeed be 100% fine too), it just needs to work in the P180 with my sig rig in it and it shouldn't be too hard to apply.

Thanks!

~ Kris

BrianE
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Post by BrianE » Sat May 06, 2006 5:42 pm

krille wrote:So would Dynamat Extreme (DE) and Vinyl combo be superior to say Acousti Products AcoustiPack Deluxe V2? Or is it just "cheaper"?
I haven't used products like Dynamat Xtreme, but I wouldn't say one is better than the other, just different. It's a bit of an apples and oranges comparison since mass dampers such as Dynamat, Brown Bread, Peel 'n Seal (roofing tape), etc. are meant to dampen panel vibrations, while porous foam products such as Acoustpack, Damptek, carpet foam, etc. are intended to absorb sound.

Think of using solid, heavy products like Dynamat as adding on more sheetmetal or making the panels heavier. They go over this a bit in the product description: http://www.dynamat.com/technical_specs_ ... treme.html

If I had enough room and was going all-out, I might actually be inclined to use both.

aowen512
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Post by aowen512 » Sun May 07, 2006 2:51 pm

BrianE, from your post, it seems that I need to figure out how my noise is being generated and go from there. Its either vibrations, or fan/hd seek noise. I need to control the fan noise. So I should be in search of Acoustpack, Damptek, carpet foam correct?

Thanks for the replies and if you have anything else to add/comment please keep this thread alive!

thx

BrianE
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Location: Vancouver, BC, Canada

Post by BrianE » Sun May 07, 2006 9:44 pm

My opinion would be that if you're sure the fans (and anything else moving...) are soft-mounted or not contributing vibration, then yes, I'd suggest foam.

That's just my $0.02 though, based on limited experience.

krille
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Location: Sweden

Post by krille » Tue May 09, 2006 7:16 am

Actually AcoustiPack and Nexus DampTek both feature a "barrier" layer, 2mm and 1.5mm thick respectively, featuring a
massive high-density (~2500kg/m^3) material.
Component: Acoustic Barrier Mass

The dark grey/black flexible acoustic barrier mass is manufactured from an EVA-based polymer compound incorporating additional components to increase the product's mechanical strength, density, durability and fire resistance. Our uniquely developed acoustic barrier material is a non-PVC based compound that is bitumen free and therefore does not give off undesirable odours or vapours when warm. It is very dense at approx. 2,500Kg/m³, and does not contain unrefined aromatic oils, lead, chromium, cadmium, or mercury. It is designed to add mass to computer casing; for example, sheet aluminium, steel, alloys and non-glossy plastic surfaces. The mass of the material acts to absorb sound energy at a molecular level as an acoustic absorption barrier, significantly reducing noise transmission and also reducing any natural resonant frequencies of the substrate to which it is adhered.
http://www.acoustiproducts.com/en/materials.asp
The DampTek® barrier layer is a flexible, sound-insulating synthetic sheet made from thermoplastic, unvulcanized rubbers (EVA-copolymers) and mineral fillers. Its high relative mass makes the DampTek® barrier layer an excellent isolator of the noise in the PC. The barrier has a self-adhesive backing.

* Excellent sound insulation characteristics /.../
* Specific mass: 2450 kg/m3
http://www.nexustek.nl/damptek.htm

As for how it performs, I don't really know. Both manufacturers provide their own numberss, but they should probably be taken with a pinch of salt.

~ Kris

lucienrau
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Post by lucienrau » Thu May 11, 2006 11:02 am

The best you can expect out of dampening is a marginal improvement. Brown Bread/Dynamat/Roofers Tape is good for dampening in an aluminum or thin steel case. It basically gives you the same effect as having bought a thick steel case to begin with. I had dynamat in a Lian-Li PC60 and then moved to an Antec case. They were much the same effect. Do not put this on if you plan on taking it off again. It's not worth it as it is a tar/bitumen substance.

There are some posts around here about the Damp-tek that you might search for. It seems to be fiddly and not that effective seems to be the consensus. Acoustipak seems to be the best from what I"ve heard, but it's not going to give you an extreme difference. I think the review said about more or less 1DB, which is great, especially for getting that last little bit of noise out of the system, but not as significant as getting quiet components to begin with, using fanmates, quieter fans and suspending drives (the best bang for your buck.) Acoustipak has both a mass barrier and foam absorbent layer.

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