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PostPosted: Tue Apr 10, 2012 4:15 am 
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With the wall being 0.5 m thick it has a weight of 800 kg/m2.
More correctly, that is surface density, not weight.

With a surface density of 800 kg/m2, transmission loss will be around 45 dB at 60 Hz, rising to about 65 dB at 4 kHz, theoretically. STC for that would be somewhere around 70-something, I guess.

But that's just the wall itself. Those windows don't look to be very substantial (even though you say they are double-glazed), and I doubt that their TL is more than about 30-something, so the total TL for that wall is about 30-something. The isolation of the brick is irrelevant. All that counts in that wall is the isolation of the windows. Without properly sealing those, adding mass to them, and then adding an inner leaf, your total isolation of the room is limited to whatever those windows are capable of producing.

That's the point I was making originally: if you only do three sides of that room as two-leaf decoupled MSM, then you have no isolation. Without the forth side being done correctly, your total isolation is the same as that of the weakest wall, which in your case is the monstrously massive but irrelevant brick, and the far less impressive windows.

One possible solution: take out the windows and brick up the gaps to the same level as the rest of the wall.

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PostPosted: Tue Apr 10, 2012 4:50 am 
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Location: Dresden, Germany
Hi...
I didn't know that word in english sorry...its a little bit different in german...
I understood the point you were making in your first post.
But, I don't need any isolation at that wall at all. At least not to the outside.
My only concern is how much sound will be transmitted along that wall to rest of the house. Is that called flanking transmission..?
Best regards
Daniel


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PostPosted: Tue Apr 10, 2012 5:41 am 
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My only concern is how much sound will be transmitted along that wall to rest of the house. Is that called flanking transmission..?
So no other rooms in the building have windows in them? There are no doors to the outside?

Yes, sound moving through the structure itself, and bypassing your isolation, is called "flanking" sound. But so is sound that goes out through those windows, then comes back in through the windows in the room next door... Or that gets into the windows or doors of other rooms in other parts of the building, or to buildings close by.

That's why the room must be isolated to the same level on ALL sides. Isolating only 3, 4 or 5 sides is not enough: Once sound gets out of the room, by ANY path (maybe even through your electrical system, or ventilation system), then it is out, and there is nothing you can do to stop it. If it is out, then it will be heard in all other locations that are not isolated. This is especially important for low frequency sound, where the wavelengths are very long.


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PostPosted: Tue Apr 10, 2012 7:20 am 
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Soundman2020 wrote:
So no other rooms in the building have windows in them? There are no doors to the outside?


I understand what you mean.
Sure there are windows at this side. No doors though.
But since there is almost nobody else in this building I don't think that its neccessary. At least not yet.
Even then sound would have to travel through the windows, outside air and through windows again.
And not one single room with windows to this side is currently in use.

Regarding your suggestion to take out the windows and bricking up the gaps....
The windows are approx. 40 cm built into the wall. Wouldn't that leave me enough space to double them?
This should improve isolation and I'd still have daylight inside which I am really looking forward to.

Thanks for your help and clarification so far.

Best regards Daniel


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PostPosted: Sat Feb 02, 2019 7:01 pm 
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For the construction of a live room, you may take advice from the developers who help you with your project. Best luck.


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PostPosted: Sat Feb 02, 2019 10:51 pm 
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renupicker wrote:
For the construction of a live room, you may take advice from the developers who help you with your project. Best luck.

Oh dear. It looks like you posted on a dead thread from seven years ago, which is a sure sign that you are a spammer....
Oh dear. It looks like your spam link got messed up somehow!
Oh dear. It looks like you got banned and blocked somehow!
How strange....

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