Originally Posted by jackforceus
Thanks For the response.
- I have heard decent reviews who have installed db3 for their home theaters. Not sure it will be 100% helpful, but my thoughts being adding a layer of sound proof material could dampen the sound
- My goal is not hear any Low frequency sound coming from the subs (that bothered me a lot on my previous home theater where I didn't install any sound proofing)
- The room is 22 ft * 15 ft with 9ft ceining
- Do I need to insulate my floor as well?
Does this help?
As Bob mentioned, DB-3 is essentially mass loaded vinyl (MLV) and, as such, is more suited for places where the flexibility is needed. That's why it's so popular in automotive sound control as well as adding mass to irregularly shaped structures. It's almost never worth it if you can instead use something like drywall with Green Glue, since the combination of the two will outperform MLV and at notably less cost. Since you're already doing double drywall plus Green Glue, I'd just skip the DB-3.
But... if your goal is to not hear low frequency effects (LFE) from the subs, then you may very well be disappointed with the results of your efforts. LFE is notoriously difficult to fully tamp down. Really, the only thing that is guaranteed to work is a thick solid concrete wall.
Even then, though, it does depend on how loud you play movies and what level the subs are at. If you're hitting 105 dB at 20Hz, then yeah, it'll be a problem if you don't have a lot of mass in play. If you're typically above 50hz or so and maybe at only 80-90dB, then you have a chance.
The key is you are missing the decoupling part of the soundproofing. Please read the first post in this thread and the two main introduction links in there. That will give you a very solid basis for how this all works.
At the very high level, soundproofing is most effective in the following order : Decoupling, Mass, Damping, Absorption. You can create a solution using just Mass and below, but you're giving up a LOT of the attenuation by skimping on the Decoupling. That's what the clips and channel (or staggered studs or double walls) will give you.
But really, start with the intro to this thread. I think it'll answer some of your questions and possibly give you some new ones that you didn't think of.