Author Topic: Soundproofing Air Ducts  (Read 13071 times)

MarkAnt

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Soundproofing Air Ducts
« on: January 04, 2011, 09:37:29 PM »
I'm in the process of soundproofing my bedroom, my new upstairs tenants are a little on the heavy side and the foot noise is killing me. I have ripped out my ceiling and I plan to insulate, mlv, sheet rock, green glue and another layer of sheet rock. I don't expect it to be silent but even a 50% reduction would keep me happy.
The other issue is that there is a shared HVAC system and their TV is placed near the air duct. So all their bedroom television noise is being rebroadcasted to me via my bedroom air duct. The ducts are rectangular metal vents that seem to transmit sound very easily. Anything I can do to the ducting to filter out some of the noise? 

Randy S

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Re: Soundproofing Air Ducts
« Reply #1 on: January 05, 2011, 05:44:52 PM »
First off...you had better use clips and channel between the mlv and drywall otherwise you will do little for your IIC rating or reducing the impact/footfall problem. A MUST DO! I promise you!

As for the vent problem you can either line the duct if its tin duct or you can line the entire cavity that the flex duct is going through with our 1/2" ssp foam mat...

you can contact me directly if need be.

Randy S.
760-752-3030 ext.104
Randy Sieg

Super Soundproofing Co
www.soundproofing.org
888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

MarkAnt

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Re: Soundproofing Air Ducts
« Reply #2 on: January 05, 2011, 10:14:01 PM »
How many inches will I lose in headroom if I use clips and channel for the ceiling?

The venting is tin duct, no flex is used anywhere in the system. How does lining the duct with foam mat prevent the sound from traveling? Isn't it passing from opening to opening?

Randy S

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Re: Soundproofing Air Ducts
« Reply #3 on: January 05, 2011, 10:45:53 PM »
If installed as directed you will lose 2 7/8" from the bottom of your joist with the 1/8" MLV / clips and 7/8" hat channel and double 5/8" drywall / green glue attached.


for a shared system you should line as much inside with 1/4" mat and then create a baffle system inside the duct with the same foam mat just 1" thickness. you need to create atleast 3 / 90 degree turns(like a rat maze) in order to get a 50% reduction.

Im surprised it is shared ducting....who gets to control the temp? ;)

Randy Sieg

Super Soundproofing Co
www.soundproofing.org
888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

MarkAnt

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Re: Soundproofing Air Ducts
« Reply #4 on: January 07, 2011, 03:52:58 PM »
I control the heat but they have a hot water baseboard so whatever they get from me is a bonus.  I will not be able to make any turns, my bedroom and theirs sit directly above the furnace so the ducting runs almost vertical to both rooms. Will a baffle make much of a difference by itself?

MarkAnt

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Re: Soundproofing Air Ducts
« Reply #5 on: January 07, 2011, 03:59:20 PM »
By the way.. Do you have any tips for installing MLV on the ceiling? I hear its VERY heavy and since its not ridged it must be a very hard trying to attach it to the ceiling.

Randy S

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Re: Soundproofing Air Ducts
« Reply #6 on: January 07, 2011, 05:06:01 PM »
Based on the fact that you will basically have a hole through the ceiling assembly it would be best if you contact me directly so we can discuss end results before you get started...you dont want to invest this money and end up with disappointing results.

Randy S.
760-752-3030 ext 104
Randy Sieg

Super Soundproofing Co
www.soundproofing.org
888-942-7723
Ph. 760-752-3030
Fax.760-752-3040