# Placement of rockwool- In front or behind perforated gypboard



## venkataraman manu (Dec 11, 2011)

Hi, Shaksters,
I am in the process of panelling my HT room. I am using gypsum perforated boards from St.Gobain and pine wood panels. My question is- Can I use the rockwool 2" or 4" _behind_ the perforated panels or should I frame and hang them in front? 
It is esthetically nice to hide the rockwool behind but my doubt is, will it still be acoustically effective as absorbers? I have visited my friend's HT where he has used them behind perforated boards and it is working there.Clap echos are not there.Clarity of voice is quite good too.No measurements done in the room though. Must I increase the rockwool thickness (to make it more effective) in case I place them behind the boards?
Any experience on it for you to share?
Thanks:blink:


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## Ile (Nov 23, 2010)

venkataraman manu said:


> Can I use the rockwool 2" or 4" _behind_ the perforated panels or should I frame and hang them in front?
> 
> It is esthetically nice to hide the rockwool behind but my doubt is, will it still be acoustically effective as absorbers? I have visited my friend's HT where he has used them behind perforated boards and it is working there.Clap echos are not there.Clarity of voice is quite good too.No measurements done in the room though. Must I increase the rockwool thickness (to make it more effective) in case I place them behind the boards?
> :


Placing wool behind panels is pretty much products whole idea. Low to mid frequency absorbtion is pretty same that bare wool. Behind panels doesn't absorbt high frequencies as effective, that is usually only good thing when big areas are covered so you won't absorbt high end too much.

Most gyptones measurements are made without and with 2" wool behind panels.
As you can see using 2" wool behind panel will save some space against just huge air gap.


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## venkataraman manu (Dec 11, 2011)

Thanks,Shakster,
But there are others ( Brian Pape, lead acoustician GIK acoustics for instance ) who feel that 
it must be in front and not behind.
So it is not as clear cut as you make it to be, it looks like:dontknow:


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## bpape (Sep 14, 2006)

If it's perforated relatively densely, it will provide some overall decay time control. I wouldn't want to use it that way at reflection points and the minimal thickness of a wall isn't going to be sufficient for deep bass control.

Bryan


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