How Do I Build A Room Within A Room?

Discussion in 'Home Theater Projects' started by Foster_G, May 25, 2005.

  1. Foster_G

    Foster_G Agent

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    I'm about to start the planning of my new home theater addition. I want to achieve good acoustical performance throughout the space. Problem is I don't have experience in drywall, isulation, sound proofing, etc. As of right now, my idea is to have a room within a room (As I have heard it called). The room will also be on slab foundation and connected to the house on the entrance wall.
    Anybody know how such construction is achieved? Is it worth the money? Or am I barking up the wrong tree entirely and need to do something else acousitcs-wise? Since I am still looking at a wall of studs, I am not limited to going one direction or another.

    The room dimensions I am looking to have are 9.5'Hx18'Wx22.5'long.
     
  2. Michael Whitney

    Michael Whitney Stunt Coordinator

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    Yes,

    Typically it is said that you build it so that the inner room is totally isolated from the external room.

    Your looking at putting another set of studs inside the current ones. Typically you want a makeup like this:

    Drywall>Drywall>Stud(filled with sound insulation>Drywall>Drywall Air Space Drywall>Drywall>Stud(filled with sound insulation>Drywall>Drywall

    Hopefully , you can picture this. Some may say that so much drywall is overkill, from what I see you use it for creating mass that cant vibrate as easily.
     
  3. Foster_G

    Foster_G Agent

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    Actually, that does make sense. My only question is that if I have an air space between the "two" rooms will that still allow sound to travel around and possible get out?
     
  4. Michael Whitney

    Michael Whitney Stunt Coordinator

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    Given that room will have a door, you will always have some sound escaping. Thats the weakest link next to windows. I forget the STC of that config I put up above. Something like 60-65, where an average room is in the 30's. If you can double heavy duty door w/weatherstripping and seal up little holes with caulk you should be very quiet. Just make sure to get good ventilation, Any electronics, projectors and 5+ people could get warm in a truly "tight" room.

    Whats the intended reason for the soundproofing?

    I have seen some setups on the sites, that get pretty pricey to truly isolate.
     
  5. Foster_G

    Foster_G Agent

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    The reason for the sound proofing is the door to the home theater is slated to be in middle of the back of the room. One side of the wall will be shared with the master bedroom, while the other will be shared by our three year-old daughter's bed room. I don't want to bother my wife or my daughter if I am ever inclined to watch a late night movie, or a late night game.
    The idea of that much drywall is pretty staggering. Judging from the drywall sheet count from above, that would increase the drywall amount to 6x the normal amount. Would doing the room-within-a-room on just one wall be sufficient and maybe adding something on the walls inside the theater to absorb sound work (i.e. carpet on the walls)?
     
  6. Michael Whitney

    Michael Whitney Stunt Coordinator

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    Seems like a tough spot to put theatre if you like it loud. Hmm, you seem to have a good width on the space. Possibly you could cut down on the sheetrock and do singles on each side. The main element is the isolation of the studs from the house.

    Possibly also a cheaper alternative would be using headphones on those late night times. Depending on how far away the equip rack is, corded or wireless. Got some good new technology with some surround capabilities out now.

    Typically the rugs on the wall ideas really knocks down the sound level inside the room and can also play havoc with the frequencies. Granted you may neeed some softer materials to help eliminate reflections, but not as alternate solution to problem.

    Anyone else got any ideas?
     
  7. Dan Keliikoa

    Dan Keliikoa Stunt Coordinator

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    Would sheets of corkboard under a sheet of drywall help?

    Cheaper, lighter, absorptive, easier to work with than all that sheetrock.
     
  8. BlakeN

    BlakeN Stunt Coordinator

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    You can buy soundboard which goes under sheetrock which is supose to absorb sound or you can install a resilient channel. It works sort of like room in room where you hang your outer sheetrock on metal channels that are attached to your studs. The metal chanels are screwed on through rubber gromits.

    You could also build a wall like this but it would be pretty expensive.

    http://soundproofing.org/images/wall_2d.jpg

    Here is a nother site that sells pretty much everything you need and will give you a good estimate of what it would cost.

    http://www.truesoundcontrol.com/prod...dproofing.html
     
  9. Paul_C

    Paul_C Stunt Coordinator

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    If you have the space to do a room within a room thats great. If you don't then do a staggered stud wall. You still get separation of the room and there is only a physical connection at the top and bottom plates.

    Instead of using two sheets of drywall on the theater side of the wall use 5/8" or ceiling board. This will keep costs down but you still get a more rigid wall and some soundproofing at a slightly higher cost.

    Good luck.

    Paul.
     
  10. Michael Whitney

    Michael Whitney Stunt Coordinator

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    Wanted to thank Blake for that 2nd link above. On that website, they have a great primer on acoustics. Interweaved with their product info, but very helpful anyway.
     
  11. Wayne A. Pflughaupt

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    Don’t worry, you don’t need all that sheetrock, as this is not how room-in-a-room construction is typically done. Think about it: It would be impossible to sheetrock the interior of both walls. Remember, they’re only a couple inches apart, so how would you get the sheetrock up on the second interior wall?

    I supposed the interior wall could be constructed as fully pre-fabbed sections with the interior sheetrock applied before the wall section went up, but that’s not the way it’s typically done.

    The construction is most typically double 5/8” drywall, stud, stud, double 5/8 again. The soundproofing is mainly accomplished by the two walls being physically decoupled, not by the additional sheetrock.

    And actually room-in-a-room construction done correctly – i.e., for maximum soundproofing - is much more than simply building a second wall. Check this post for more information.

    Regards,
    Wayne A. Pflughaupt
     
  12. Foster_G

    Foster_G Agent

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    Wayne that solution sounds like the most economical choice. I hate cutting corners on things that I have spent a lot a years dreaming about having. Going through your post I followed a link to Erik Farstad theater construction. From Blake's post I was noticing some of the products from TrueSoundControl, I am wondering if the asphalt sheeting Erik is using is practical and would work as a thin sound absorbing membrane between the studs and the double drywall which I think might be the best way to go money-wise.

    I know nothing about roofing materials, but would something like that work inside a room without any complications, if any?
     
  13. Wayne A. Pflughaupt

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    Can’t help you there, Foster; I’ve never used any of those materials.

    Regards,
    Wayne A. Pflughaupt
     
  14. ChrisWiggles

    ChrisWiggles Producer

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    First, the original post mentioned acoustics, while the question is directed towards isolation. These are two different things.

    For room isolation, as mentioned this is very difficult to do very well, you really do want a decoupled, sealed, double-walled room all the way around. This is worth hiring a professional to make sure you are doing it right and not wasting time, effort, and money by not knowing what you are doing. This is no minor project if you really want a completely isolated room. You can do this more reasonably as well. As for the isolation, the "absorption" of these materials is minimal. The whole point for isolation is a barrier, not absorption really at all. You want decoupled MASS. This blocks sound. To have any reasonable hope of absorbing bass from passing through a wall, you'd need many many MANY *feet* thick of dense absorption. Much easier to build a pair of heavy decoupled walls as a barrier than trying to absorb that energy.

    In-room acoustics is a different discussion entirely, and *that's* where absorption comes into play...
     
  15. BlakeN

    BlakeN Stunt Coordinator

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    I think the staggered stud wall would be a good idea. That would give you quite a bit of isolation and it would be a heck of a lot easier.

    Wayne - so how would you get the sheetrock up on the second interior wall?

    you build the wall on the floor attach the inner drywall and then put it up. In other words a great big pain in the butt.

    Wall in wall is just a mamoth Diy project. If you can afford to have somone do it for you then I wouldn't bother. Build a second single car "garage" and have your HT completely isolated from your house.
     

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