Author Topic: Sound proofing has made the noise worse  (Read 755 times)

Offline batman diver

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Sound proofing has made the noise worse
« on: May 10, 2017, 07:49:25 AM »
I am hoping I can find some insight please, at work the neighbors are behind a dry wall this has been insulated and poses no problem, but the sound is now coming through the suspended ceiling, so we added some isotherm, that worked a bit ....
We then added cavity batt and built a cavity batt "wall" between the two rooms in the ceiling ( we put the cavity bat on its side )

This has made everything much worse ..... does anyone know how or why ?


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Offline DRNB

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Re: Sound proofing has made the noise worse
« Reply #1 on: May 10, 2017, 07:55:45 AM »
Mainly because a cavity is actually a good insulator.

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« Last Edit: May 10, 2017, 08:25:51 AM by DRNB »
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Offline batman diver

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Re: Sound proofing has made the noise worse
« Reply #2 on: May 10, 2017, 11:03:06 AM »
Hmmmm so i must maybe try take the "wall" down and leave just the flat pieces

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Offline DRNB

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Re: Sound proofing has made the noise worse
« Reply #3 on: May 10, 2017, 11:13:08 AM »
Haha... Funny thing is for good insulation some afsorbsion inside the dry wall is good. But you need the cavity as well.
Ideal would be drywall panel, absorbsion, cavity, drywall panel.
What you could do now is to leave it as is, but add another drywall panel against the wall, but with minimal direct contact to the existing wall.

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Offline d0dja

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Re: Sound proofing has made the noise worse
« Reply #4 on: May 10, 2017, 04:35:42 PM »
The main thing to look at is what the sound can use as a medium. Sound travels. Dry well through certain solids. It may be that the wooden bracing for your firewall has created a physical coupling between your neighbour's ceiling and your ceiling.

There are two ways to stop sound energy moving... damping (ie turn sound energy into heat in a material like isotherm), or creating a large discontinuity between materials (ie the sound bounces back from the discontinuity, can't cross it).

If your structure gives sound a pathway to get around the damping or discontinuity, it will take it. 

Offline Ricketysmurf

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Re: Sound proofing has made the noise worse
« Reply #5 on: May 14, 2017, 09:13:45 PM »
I am hoping I can find some insight please, at work the neighbors are behind a dry wall this has been insulated and poses no problem, but the sound is now coming through the suspended ceiling, so we added some isotherm, that worked a bit ....
We then added cavity batt and built a cavity batt "wall" between the two rooms in the ceiling ( we put the cavity bat on its side )

This has made everything much worse ..... does anyone know how or why ?


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Sounds like you gave the sound a channel by connecting the two walls with the cavity batt. A rubberised strip to stop the cavity batt touching the walls should help.
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Offline mustang76

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Re: Sound proofing has made the noise worse
« Reply #6 on: May 31, 2017, 10:21:15 PM »
The main thing to look at is what the sound can use as a medium. Sound travels. Dry well through certain solids. It may be that the wooden bracing for your firewall has created a physical coupling between your neighbour's ceiling and your ceiling.

There are two ways to stop sound energy moving... damping (ie turn sound energy into heat in a material like isotherm), or creating a large discontinuity between materials (ie the sound bounces back from the discontinuity, can't cross it).

If your structure gives sound a pathway to get around the damping or discontinuity, it will take it.

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Offline d0dja

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Re: Sound proofing has made the noise worse
« Reply #7 on: June 01, 2017, 10:44:04 AM »
" Sound travels. Dry well through certain solids."

This is obviously meant to say "sound travels very well...". Damn autocorrect.

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