Thread: Noise Cancelling Foam

My initial post deliberately neglected to mention that in one way or another, I've had involvement in soundproofing and acoustic control in a recording/rehearsal environment for the last 8 years and while I'm not one of the countries' experts, I do know what does and doesn't work.

Hi Sean
Check this website out. Its just down the road from you at Slacks Creek. They specialise in sound deadening materials.
www.insulationsuperstore.com.au/location.php
Neil

Originally Posted by neilb

Hi Sean
Check this website out. Its just down the road from you at Slacks Creek. They specialise in sound deadening materials.
www.insulationsuperstore.com.au/location.php
Neil

And both noise oriented products state that effectiveness is dependant on the structure itself.

Guys, PLEASE understand, that regardless of what claims manufacurers or resellers of a product may make, acoustic/sound deadening batts, foams and sheets, etc., are only one part of the solution, by themselves, they will provide "some" benefit but ultimate control is dependant on the structure itself which provides the necessary mass and mechanical de-coupling.

Unfortunately, if you want or need true control of sound, there are no magic wands, no shortcuts and no cheap fixes.

i havent got much to add to this but completely right.. ive done some sound training latey and asked this question.. the answer was good insulation in the walls or carpet on the walls.. and foams like this are for frequency controlling

Originally Posted by HiString

Very loosely speaking, acoustic foam is designed for controlling sound (audio frequencies) in a listening or recording environment NOT for soundproofing, this is a totally different ball game and rarely is there much common ground. Soundproofing is incorporated in a structure, the foam or other "treatments" are applied after the structure is completed.

To reduce sound to any significant degree you need mass and to decouple the inner "walls" from the outer "walls" as much as possible, additionally, a soundproof "space" needs to be virtually airtight as even the most insignificant weakness there will allow a disproportionate level of sound to escape. If I ever get to make the CNC router I have the gear for, I'll be building an enclosure...........this will be in the form of a box within a box with minimum contact between the two, possibly neoprene blocks. Materials are likely to be heavy MDF (mass), the void between will be packed with Rockwool which is close to the most dense insulation "batt" available. The only point where this design may be compromised is where power and dust extraction have to be incorporated.

Meansy,

Not sure where you're getting your answers but by itself, insulation, good or bad, in a wall won't do much for soundproofing and carpet on a wall is no different to acoustic foam......it just affects marginally different frequencies.

Ultimately, regardless of the situation, anyone needing soundproofing, has to determine to what degree they need to reduce that sound, then they are in a better position to determine what is necessary to achieve that result.

HI Guys,

Just thought I would fill you in on what i am up to, I have welded up an enclosure 1.2 x 1.2 and 2 meters tall pic attached.

Did a a test on Sunday, what I did was take the Die Grinder and placed it in the fridge and turned it on.

I wont tell you what the wife said when she had seen what I was doing it was quite how would you say abrasive but it did prove that mass is something I will be thinking hard about for the next couple of days.

I think I am going to build like a sandwich on the outside of the enclosure and may make another inside if required as when the Die Grinder is cutting you get that wonderful high pitch noise and one layer of MDF wont do it and if its running for 6 hours straight I don't want to get shot by the wife or neighbours.

Thanks for the comments guys keep them coming I will post my progress as I go.

Sean

Sean,

Unfortunately, I can't see your pic........maybe a problem with my PC settings or it may not. Anyway, there's some info that may help at the following links...............

http://www.bradfordinsulation.com.au...=Design+Guides

.......and from that list....
http://www.bradfordinsulation.com.au...104pg30_34.pdf

Figures 20 and 28 in the second link may be relevant, although I'd replace the steel sheet with thick MDF.

Brilliant HiString just what I needed .

reaffirms what you have been saying.

Sean,

Something else which I don't think is mentioned in that info is that if you're "multiple sheeting" (ie: more than 1 layer of MDF, Gyproc, ply, etc.), it is more effective to use 2 different density products.........ie:thickish plywood and MDF...........the reason being that more "energy" is lost in the transmission/transition through the change of density (mass).

Originally Posted by HiString

Meansy,

Not sure where you're getting your answers but by itself, insulation, good or bad, in a wall won't do much for soundproofing and carpet on a wall is no different to acoustic foam......it just affects marginally different frequencies.

Ultimately, regardless of the situation, anyone needing soundproofing, has to determine to what degree they need to reduce that sound, then they are in a better position to determine what is necessary to achieve that result.

sorry bout that yer i realise wat i said wrong lol..

Another "amplification" of HiString's comments (which are all right on the money) is that if you do use layers, try to avoid fasteners like screws or nails that connect all the way through from the first layer to the last or into studs or framing. If you do, you're just coupling the inside layer with the outer and the framing. One trick we did in a recording studio was to use a double studded wall with the 2 x 4 studs on 2 x 6 plates off-set so one wall didn't touch the other, then we used 5/8 sheetrock, a layer of low density Celotex fiberboard that was just glued to the sheetrock, and then another layer of 1/2" sheetrock just glued to the fiberboard. We'd put up a layer with construction adhesive and screws, let the adhesive dry and then remove the screws. This was incredibly effective, even down to pretty low frequencies. As HiString says, mass and decoupling is what you need.