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  • Dallamarr - Sunday, June 15, 2008 - link

    i can 100% confirm that the multi drywall layers is what movie theaters use. I worked for one from 99 to 01 and in that time we had some construction done on one of the houses and was able to view the cross section of a wall that was cut out.

    3 layers of 1/2" drywall over metal "studs" with standard insulation inbetween the studs. with that crappy carpt over the drywall. theater was bulit in early 99.. about 3 months before I started there.

    if anyone ever has some balls and brings a flashlight with them... goto the front of the theater before you show starts and there should be a "curtain" at the bottom of the screen you can lift up and get behind the screen. it might be tight squeeze, I am 5'10" and I had to crawl under to get back there. (the contracted night crew used leaf blowers to push all the trash to the front for clean up, lot of nasty junk got pushed behind)
  • xxPaulCPxx - Friday, January 25, 2008 - link

    Instead of doing a regular installation of a single set of double door, double your door layer. Have one set of doors flush with the outside of the jam, and another pair flush with the inside. Each set only needs a full handle on the exterior face, the interior can have a low profile inset pull. The slabs themselves should be solid core, of course.

    If you don't have enough room for doors to open on each side of the opening, you can make one set a surface mounted sliding door. Basicly it is an exposed pocket door with hardware hidden in trim. Hafele makes this kind of hardware and would hav some great examples. You could finish the sliders the same as the walls if you wanted them to be less noticable.

    Using double closed doors makes a tremendous difference in our house, where we have loud playing kids and lazy napping adults!
  • TW - Saturday, January 26, 2008 - link

    Paul is right on the money regarding the double doors. The pocket door or flush mount isn't going to be sealed, so that makes it not such a prime option. If you can install two (solid core) door slabs and seal them with heavy weatherstrip, you are off to the races.
  • Shazam - Saturday, January 19, 2008 - link

    Too bad you've already drywalled. You should've used QuietRock drywall. That would've removed the need for two layers of drywall (not really effective, actually) - one layer of QR is equivalent to EIGHT layers of standard 1/2" drywall.

    Metal studs should've also been used instead of wood. Roxul Safe'N'Sound should've been placed between the studs.

    Sound insulating mats should've been placed between the studs and joists and the drywall.

    And weight has little to do with blocking sound transmission - density changes in materials is much, much more effective.

    Blocking should've been placed where you wanted to place speakers.
  • TW - Wednesday, January 23, 2008 - link

    And SOund Isolation mats I assume is a reference to Mass Loaded Vinyl. Which is just mass. Nothing more, nothing less. Effective? Sure. About as effective as another sheet of drywall. Again, it's just mass.
  • TW - Wednesday, January 23, 2008 - link

    Also, standard fiberglass performs as well as anything. Check out the exhaustive research on this topic done by the NRC in Canada. Finest Acoustics facility in North America, perhaps the world. Their conclusion (see the data for yourself) is that fiberglass had a slight edge in the lower frequencies, while mineral fiber had an edge in the upper frequencies.

    Since that wall is decoupled, heavy and insulated, higher frequencies are not the concern... low frequencies are. So plain old fiberglass isn't just the cheapest option, it's also the best for this application.
  • Shazam - Saturday, January 19, 2008 - link

    Oh, and you should've used 2X4 studs, staggered on a 2X6 plate.
  • strikeback03 - Wednesday, January 23, 2008 - link

    Did you read earlier posts? He said the room was framed before talking to the sound guy, thus no staggered studs and the mettal on rubber thingys.

    Is that a fireplace visible to the left through the double door opening?
  • TW - Wednesday, January 23, 2008 - link

    Disregard the ner-sayers. Fact is that the wall you are building is superior to what you would have seen with Quiet Rock. Your wall is heavier, and better damped and cheaper. There is fully certified lab data to back that up. Not an idle claim.

    Regarding the "1 sheet of quiet rock = 8 sheets of regular" there's no lab data to support that anywhere. It's a marketing line. Too bad, because it's not a bad product line.
  • xxPaulCPxx - Friday, January 25, 2008 - link

    If it works as well as 8 sheets that's pretty good. Unfortunatly 1 sheet of QuietRock costs as much as 10 sheets of regular drywall!
  • TW - Saturday, January 26, 2008 - link

    It does not perform as well as 8 sheets is my point. Never been tested, and likely never will.

    Standard drywall = $8
    quiet rock 530 = $120
  • paperfist - Monday, February 11, 2008 - link

    There's a show on Discovery Home called Holmes on Homes where they used that product to replace standard drywall between 2 homes with a shared wall. I don't remember the dB readings but they blasted a radio on one side of the wall and measured the sound on the other side. The results were nearly silent. In the previous state both home owners complained they could hear each others conversations clearly even in other ends of the house.

    Personally I used the double drywall 'trick' as recommended to me by my insulation contractor. What a waste that turned out to be, there's virtually no difference in noise transmission and the added costs both in materials and labor have to be considered to hang 2 sheets vrs one quiet rock sheet.

    I'm def trying it out in the next room remodel :)
  • TW - Wednesday, February 13, 2008 - link

    I saw that show also. Not the full story. To really analize what works best, you have to remove all the variables possible and have tests done in certified acoustic labs.

    As it happens, when you do this, you see that quiet rock isn't at the top of the food chain, is expensive and don't forget you have to throw away an average of 12% as waste.
  • paperfist - Tuesday, February 19, 2008 - link

    Per your post below I assume you mean bat fiberglass as in insulation? I spent a lot of money on that stuff and it didn't remotely live up to expectations to dampen sound between floors.

    As far as lab testing and variables go I'm not sold. They played a radio between 2 walls and the sound transmission was obvious. They ripped the drywall down, insulated, used a sound deadening tape on penetrations and then finally used quiet rock. They replayed the radio and the difference was night and day.

    True I'm sure there's some stuff going on behind the scenes, but lab testing means nothing to me. The EPA would like you to believe your car is going to get 30 MPG...in a lab. In the real world many of us know those numbers to be useless. In a lab or even on paper my SATA drive is suppose to wipe the floor with my ATA drives. It's not the case.

    I never used quiet rock, but as I've said I'll be redoing my living room shortly which will include ripping down everything to the studs. If I can get my hands on the stuff I'll try it out. I don't remember the exact figure, something like it's like using 15 sheets of drywall? I'm certain they are stretching the truth on that one.

    What do you consider to be the top of the food chain? From experience I can say the fiberglass bat insulation designed to deaden sound and double drywall didn't work for me.
  • TW - Tuesday, February 19, 2008 - link

    Paper,

    Labs are the only way to isolate variables. Otherweise you have no idea at all what works and doesn't because of the dozens of possible contributing elements.

    Quiet rock certainly works, but the "1 = 8" is just plain BS marketing.

    There are only 4 things that can deal with sound:

    Mass: like drywall, MLV, plywood, cement. All really heavy

    Absorption: Generally used in hollow areas such as stud and joist cavities.

    Decoupling: This separates the drywall from the studs or joists for example.

    Damping: This is what quiet rock, green glue, etc do.

    The problem with your ceiling project was that you had no decoupling. The footfall vibration completely overwhelmed what you did. Very common.
  • ltfields - Friday, January 18, 2008 - link

    I hear ya on the Drywaller complaints, when I had a drywall contractor finish off my basement (since everyone I talked to said contract it out), they were a pain to deal with. They didn't want to drywall the underside of my staircase, and I fought with them on speaker mounts in my home theater as well(though I didn't do the isolation and gluing you did). If they didn't do such a good job, I'd be more angry, but it's like pulling teeth sometimes...

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