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Discussion Starter · #1 ·
I've been considering building speakers and subs with two layers of MDF, and a layer of cork between them.

However, I found out that cork expands and contracts with small water exposure (fear: humidity).

And I want to give my projects a mirror finish, so I can't have it expanding and cracking my auto paint/clear.


Is there another material that I can use, in the place of cork?

And because this isn't a speaker building forum, I will explain the purpose of cork: It's a dissimilar material, compared to MDF. It's softer, and resonates at a lower(?) frequency.
That should reduce the noise that gets 'out' of the box.
 

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Not knowing anything about speakers or how exactly you are sandwiching the cork, what about foam core board or other rigid foam insulation?
 

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icor1031 said:
I've been considering building speakers and subs with two layers of MDF, and a layer of cork between them.

However, I found out that cork expands and contracts with small water exposure (fear: humidity).

And I want to give my projects a mirror finish, so I can't have it expanding and cracking my auto paint/clear.

Is there another material that I can use, in the place of cork?

And because this isn't a speaker building forum, I will explain the purpose of cork: It's a dissimilar material, compared to MDF. It's softer, and resonates at a lower(?) frequency.
That should reduce the noise that gets 'out' of the box.
There are sound deadening sheets available. JCWhitney used to catalog them, as well as Crutchfield.

Amazon has some from 3m and FatMat

If you know a commercial roofer they may have scraps of EPDM sheet roofing that would work.
 

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Discussion Starter · #5 ·
Not knowing anything about speakers or how exactly you are sandwiching the cork, what about foam core board or other rigid foam insulation?
Foam doesn't work well at sound absorption. :boat:
Also, I think it's called laminating. I will glue the layers together.





For interior use, and especially being sandwiched, cork may not be that subjective to whatever minor swings in interior humidity. If you want to consider an alternative, Homasote board may work.
I looked up Homasote, and it has the same problem. Do you think it has similar or better resistance to swelling? Homasote is about the same price as cork, and easier to get. I think I would prefer that.

And if you think that with it being sandwiched it won't swell enough to cause problems, I may do that. :thumbsup:

http://cs.trains.com/mrr/f/11/t/81402.aspx
But it is hydroscopic and will swell notieably in high humidity.


There are sound deadening sheets available. JCWhitney used to catalog them, as well as Crutchfield.

Amazon has some from 3m and FatMat

If you know a commercial roofer they may have scraps of EPDM sheet roofing that would work.

Unless I'm looking at the wrong thing, those are much too thin.

Thanks, everyone!
 

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I looked up Homasote, and it has the same problem. Do you think it has similar or better resistance to swelling? Homasote is about the same price as cork, and easier to get. I think I would prefer that.

And if you think that with it being sandwiched it won't swell enough to cause problems, I may do that. :thumbsup:

http://cs.trains.com/mrr/f/11/t/81402.aspx
I've never paid much attention to whether there was a problem with it that way. I don't remember any. I would think that having it sandwiched between plywood, and sealed in with a finish, that it would be fairly well protected. It would have to move the plywood, and that's asking a lot.






.
 

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icor1031 said:
Foam doesn't work well at sound absorption. :boat:
Also, I think it's called laminating. I will glue the layers together.

I looked up Homasote, and it has the same problem. Do you think it has similar or better resistance to swelling? Homasote is about the same price as cork, and easier to get. I think I would prefer that.

And if you think that with it being sandwiched it won't swell enough to cause problems, I may do that. :thumbsup:

http://cs.trains.com/mrr/f/11/t/81402.aspx

Unless I'm looking at the wrong thing, those are much too thin.

Thanks, everyone!
I don't think you need all that thick of a layer. And I'm not sure you need anything. The MDF, is pretty solid stuff. But, it doesn't really resonate well due to the variation in internal densities of the particles.
 
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