# Acoustics Treatment Materials



## nzone (Sep 20, 2010)

From the research that I have done so far, it seems that OC 703/705 is the popular/prefer material to use for bass traps and acoustical treatments, why? When looking at http://www.bobgolds.com/AbsorptionCoefficients.htm :

OC 703 3"
3.0 pcf (48 kg/m3)	0.53	1.19	1.21	1.08	1.01	1.04	1.10

Safe n Sound 3"
2.5 pcf (40 kg/m3)	0.52	0.96	1.18	1.07	1.05	1.05	1.05

Both materials acoustical absorption properties are very similar. I know that OC 703/705 are rigid vs Roxul semi-rigid, but if one builds a frame for it, isn't that a wash? The OC is very hard to find locally vs easy to find Roxul at Lowes or HD. Cost wise, Roxul is a 1/3 the cost of OC. 

Is rigidity the deciding factor?


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## bpape (Sep 14, 2006)

Either can be used just fine. As you said, the mineral wool is not as rigid and some people have the fear of it 'slumping' over time. 

The 703 is also MUCH easier to work with in terms of cutting it cleanly if that's required.

Bryan


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## SAC (Dec 3, 2009)

An easy solution to supporting the material is to use cheap plastic orchard bird netting (available at the WalMart garden center) to help support the material - Just staple it to the frame.


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## nzone (Sep 20, 2010)

bpape said:


> Either can be used just fine. As you said, the mineral wool is not as rigid and some people have the fear of it 'slumping' over time.
> 
> The 703 is also MUCH easier to work with in terms of cutting it cleanly if that's required.
> 
> Bryan


Great! Thanks BPape for the confirmation. According to Roxul, the Safe'n'Sound maintains its shape for decades and won't slump or settle over time. 

For constructing the panels, can I make everything broadband or cover some with 4/6 mil vapor barrier plastic and fabric to allow high frequency reflect back to the room?


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## nzone (Sep 20, 2010)

SAC said:


> An easy solution to supporting the material is to use cheap plastic orchard bird netting (available at the WalMart garden center) to help support the material - Just staple it to the frame.


Is that the insect screen?


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## SAC (Dec 3, 2009)

No. It is orchard bird netting... a more open mess plastic bird netting used to cover fruit trees and keep the birds out in order to protect the fruit.

It is sort of like a smaller version of chicken wire.

It is a common farm/garden resource, although most may not be familiar with it.

Just do not buy the premium versions designed to last seasons in UV environments. You just need 20'x 25' panels available for about $4.50-$6.00 each. Less if you catch the season end sales.


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## nzone (Sep 20, 2010)

SAC said:


> No. It is orchard bird netting... a more open mess plastic bird netting used to cover fruit trees and keep the birds out in order to protect the fruit.
> 
> It is sort of like a smaller version of chicken wire.
> 
> ...


I've never planted anything in the backyard. :bigsmile: This is the one? Orchard Bird Netting


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## SAC (Dec 3, 2009)

Yup. That will work.


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