annoying about neighbours' air-con engine noise

Posted: Fri Aug 29, 2008 7:55 am

This is my new designing studio in Hong Kong, in commercial building on 15/F.

the bigger one is for control room, smaller one is for tracking.
At the beginning,
the back side of tracking room are windows,
I block this windows by using three layers, each layer contains two sheets of plasterboard, 4cm between the layers.

However, after I build this room,
I hear some "WO~~~" sound,
this should be the vibration of neighbours' air con engine.

In this moment, I have only constructed the plasterboards with rockwool,
without adding the absorbing and diffusing materials.

How can I reduce this noise?

I can give more information if needs~~
please give me your opinions thanks~[/img]

Posted: Fri Aug 29, 2008 10:08 am

From you have described, you have a triple leaf in the window. This would have terrible sound isolation at it's MA... frequency. More information on the window blocking and wall construction is needed to confirm. The first thing would be to tear down the current window blocking and build it as two leafs. Or remove two of the leaves and build the second one with 4 layers of gypsum.

Andre

Posted: Fri Aug 29, 2008 7:15 pm

Andre,

it's actually a quad assembly - the windows themselves become the last leaf.

Very not good assembly.........

Rod

Posted: Fri Aug 29, 2008 10:49 pm

as I don't know a theory about two leafs are better than triple.
Is it the issue of even/odd number of leafs?

for wall construction,
I will confirm it and post it later~~

thanks so much~

avare wrote:

From you have described, you have a triple leaf in the window. This would have terrible sound isolation at it's MA... frequency. More information on the window blocking and wall construction is needed to confirm. The first thing would be to tear down the current window blocking and build it as two leafs. Or remove two of the leaves and build the second one with 4 layers of gypsum.

Andre

Posted: Fri Aug 29, 2008 11:32 pm

More than two leaves reduce the TL at the low frequencies of the (smaller) cavities. A search of the forum for "triple leaf" should give much information.

Andre

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