Author Topic: Basement Home Theater  (Read 4014 times)


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Basement Home Theater
« on: November 20, 2008, 07:40:02 PM »
I am in the final stages of completing my basement home theater and would like to soundproof it from the rest of the house.  My question is with regards to using mass instead of resilient channel to significantly reduce sound.

Since the home theater occupies the corner of the basement I was thinking of attaching a layer of cement barker board directly to the studs on the inside of the home theater on the 2 interior common walls. Then regular 1/2 inch drywall would be glued onto the cement board to crate a finished interior.  These walls will be insulated  and covered on the other side of the studs with a layer of 5/8 inch drywall and finally glued to it a layer of 1/2 inch drywall.

In summary; from the inside of the home theater out to the rest of the basement would be as follow:

1/2 inch drywall -- glue -- 1/4 inch cement board screwed to wood studs with roxul noise reduction insulation between the studs --5/8 inch drywall screwed to wood studs -- glue -- 1/2 inch drywall. Will this configuration give me a significant stc improvement over a basic resiliant channel installation, or not?

The ceiling would be conventional resilient channel/drywall.

Your comments are sincerely appreciated.



  • Guest
Re: Basement Home Theater
« Reply #1 on: November 23, 2008, 12:48:25 AM »
The best result is by using both: mass (extra drywall, etc.) and decoupling (resilient channel).  Also, cavity absorption (insulation) and sealing the wall are important, too.

You can put up ridiculous amounts of drywall on a stud wall and get better soundproofing, but without some kind of decoupling (resilient channel, staggered studs, double studs) you still have a direct mechanical connection from one side of the wall to the other, a 'path of least resistance' for vibration transfer. 


A regular stud wall (1/2" drywall, studs, 1/2" drywall) has an STC of 32-33.  Let's say you were shooting for an STC of 55, a pretty good value.  If you were to just add mass to reach that goal, you'd need to double the mass for every 6 point increase in STC.  To get an additional 22 points and get you to your goal, you'd need to 'double the mass' 3.66 times over, or increase the total mass by a factor of 12.7 (2^3.66).  That means adding an additional 13 layers of drywall to each side.  Pretty ridiculous, don't you think?

Whereas, if you use mass+decoupling correctly, you can achieve the same thing with a lot less materials, not to mention money.  A well-sealed wall with resilient channels, two layers of 5/8" drywall and insulation in the stud cavities rates an STC of 59, and even higher if you use SSP clips (sold on this site) plus hat channels instead of RC-1.  You can get an STC of 64 with that method, about the same value as if you built double walls.