Originally Posted by TechEnthusiast
Indeed. My original plan would have had little effect on sounds entering and leaving the room.
You're correct. It's a small storage room at the center of my home.
Thank you for the clarification. I now have a better understanding of what a "room within a room" means.
You and Deewan are correct. Turns out I didn't know the real definition of "room within a room." To be clear, it's a simple storage room at the center of my home.
If I were to tear down the drywall and isolate the stud walls from the ceiling as well as install clips and a hat channel, I suspect that I might still need to do a lot more. The cars, trains, and airplanes are quite loud. Perhaps I should just move and build another home from scratch? On the other hand, how about sound isolation booths/enclosures (e.g., WhisperRoom, VocalBooth, StudioBricks)?
What's highly problematic is the feeling that most low frequency sounds produce. Would GG and three (or four) layers of drywall make a noticeable difference in terms of mitigating the physical sensations generated by low frequency sounds as well as reducing those in the mid- and high-frequency range?
So far I have scrapped my original idea. I am also deterred by the prospect of tearing down walls and installing layers of drywall. No guarantee that it'll work...or be done correctly.
I wouldn't be so deterred. If you tear down the drywall and add clips and hat channel, then layer on drywall and green glue, it WILL noticeably reduce the sound leakage. Even if you did a bad job, you would have to so significantly screw up for it to not be noticeable. The mistakes you (and all of us) make would minor in absolute terms, they are only significant in a value way. You put a lot of time and money into sound isolation, you don't want silly mistakes to cost you precious STC points. Remember that STC is a kind of weighted average of the transmission loss, in DB's, over a specified frequency range. That isn't an intuitive concept, but db's and volume is. If your mistakes lead to a penalty of 3db's at 1khz, well, let's be realistic, that is noticeable but not huge.
The mass and the CLD will help dissipate some of the energy, so its not for nothing. I would need to know a lot more about your theater equipment, subwoofers, and house construction to fully answer your questions. Vibrations travel through solids readily (as does sound). In many homes, the floor has joists that connect multiple rooms together (running most or all of the length of a span of the house). For example, the kitchen and living room in my house are on the same set of joists, as is half of the dining room. The dining room is completely separated from the kitchen and living room. Further, the joists are connected to the next "group" and could transfer that energy. As such, the interconnectedness of the floor allows vibrations produced in one area to travel throughout the first floor. Thankfully, energy is "shed" as it travels as a result of friction. The vibrations dissipate over time as they travel farther out, they also spread in a circular arc and so the inverse square law states that for a doubling in distance, energy is 1/4th. There are things that can make that not true, but lets just pretend like it is. What that means for you is that if you are feeling the vibrations intensely, even a fully soundproof room may not have fully isolated all paths for sound and energy to travel, and so you may still feel the bass.
Before going down this road, I would consider a few things. First, you may need to decouple your floor. A cheap starting point may be to try decoupling the subwoofers from the floor to see if that helps. If it does, then you need to decouple your entire media rooms floor. Second, that you may want to consider heavy duty soundproofing since your concern is primarily bass. That is by far the hardest area to address, so consulting experts can be helpful. In general though, the best LF isolation is possible when your airgap is large, your wall mass is great, damping is high, and the outershell is stiff. This has the best potential to "contain" lf energy.
p.s. look up decoupled floor. If ripping drywall down scared you, that will be worse. Again, its not as bad as it seems.
P.P.S. even with new construction the effort to do this is significant and fairly expensive. Most houses aren't built for soundproofing.