Soundproofing a great room in new construction

Discussion in 'Home Theater Projects' started by Triad Caniac, Aug 30, 2004.

  1. Triad Caniac

    Triad Caniac Auditioning

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    Jarrett
    I am having a house built and the only real option for the home theatre is in the great room. It is a fairly open floor plan that certainly isn't perfect, but will have to do.

    I have a decent system (Denon 5803 with 7.1 Atlantic Technology System 370THX speakers), so it can get loud and can easily be heard outside. I thought about soundproofing three walls and the ceiling to help reduce noise outside the room. My only concern is to help prevent the neighbors from calling the cops when watching a movie. The one adjacent home will be fairly close, so I want to minimize sound travelling to them as much as possible.

    I did some research and read about Acoustiblok and QuietRock. I contacted three local CEDIA certified installers and asked some general questions and price ranges. All of them suggested the heavy vinyl treatment on the studs before the sheetrock goes up. My builder is fine with that, he will simply call me when they get to a point and then the outside contractor can come in. Problem is, two installers estimated $15,000 and one said under $3,000.

    When speaking with the one on the low end, he said he can install heavy vinyl (not Acoustiblok brand) in 54" wide 30 ft. rolls for $199/roll. He said to estimate $25-$30 per roll for additional materials and labor. Based on my measurements, I have about 900 square feet to cover, and I can get out with around 7 rolls. That's within my budget, $15,000 is not.

    My questions are:
    1. Is this going to work in the end?
    2. Any ideas on the large cost difference between installers?

    Any other thoughts/suggestions are greatly appreciated.

    Thanks in advance,
    Jarrett
     
  2. Wayne A. Pflughaupt

    Moderator

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    Jarrett,

    First welcome to the Forum!

    It’s hard to tell from your post if you’re only trying to keep sound contained inside the house, or out of other rooms as well. Since you’re using an open family room, I wouldn’t expect to accomplish much with the latter.

    The cheapest and most effective way to soundproof (i.e., keep sound contained) is double-walled construction like they use in recording studios. Here is an old post of mine that gives the particulars.

    Here is a link to another post with other soundproofing ideas and materials.

    Keep in mind, however, the further away you move from full double-walled construction the less containment you can expect. And as you can see from what these contractors are quoting, you’re also paying more for less.

    You didn’t really define what you mean by “close,” but if both you and your neighbors have brick homes I don’t expect you will have a problem disturbing them, irrespective of aggressive build-out techniques.

    Consider what you already have for “free”: The outside walls are normally extra-thick, coupled with the added density of brick or siding. In addition, the house is virtually airtight, which is another very effective soundproofing technique. Then you have some open air space between the two structures, which serves as an excellent diffuser of sound waves. After that you duplicate the neighbor’s construction again. That’s an awful lot for sound to penetrate, even problematic low frequencies.

    Regards,
    Wayne A. Pflughaupt
     
  3. chris_everett

    chris_everett Second Unit

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    $199 a role is a very good price. Almost too good. On the other hand, $15,000 is absurd. I don't know how they can justify that kind of cost (Or anywhere close). I would expect $5-6000 for the job would be reasonable. The purpose of Mass loaded vinyl is to make wall partitions more dense, which it does do very well. It's also more forgiving of mistakes than double walled construction or resilient channel (IMHO) Although it takes a full double wall construction to have studio-level isolation, (60db +) a "compromised" install will still be very effective for HT.

    The three keys to soundproofing:

    Airtight.
    Dense wall partitions.
    Dead Air-space between walls that are accousticly seperated.
     
  4. Triad Caniac

    Triad Caniac Auditioning

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    Thanks for the tips so far...

    I'm really just trying to keep sound inside the house and away from the neighbors. The houses will be less than 30 feet apart, maybe closer. The part of the home facing the neighbors will be vinyl siding.

    The home we have now is very close to the neighbors, about 20-25 feet, and has vinyl siding. I don't have any soundproofing and I'm on a crawlspace, so when watching movies in the -17 to -10 range it can easily be heard outside in their driveway. I'm pretty sure they can hear it inside their house as well as they've commented (but never complained) about the noise. The new home will be part of a homeowner's association, so I certainly don't want to get fined just for watching movies!

    One other question I thought of after reading some of the other threads...I will most likely be on a slab foundation and I understand that changes the bass response. Will that help to reduce some of the low level noise they might hear/feel?

    Thanks again for everyone's help!
     
  5. anth_c

    anth_c Stunt Coordinator

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    Jarrett,

    Another avenue to investigate are the window and exterior doors: similar to heating and cooling, the quality of the windows and doors will have a large impact on the amount of sound that is transmitted to your neighbors.

    The same things that increase energy efficiency will reduce the amount of sound transmission:
    -Windows that have double or triple pane glass
    -Windows tightly installed and caulked
    -Exterior doors that are solid core wood or metal with insulation.
    -Exterior doors that have weather stripping on all four sides.

    Will the walls be 2x4 or 2x6?

    How many walls of the great room are exterior walls?

    I think installing double layers of drywall or resilient channel on these exterior walls and installing quality windows and doors would significantly reduce the amount of sound that escapes the house. This would also provide a good cost/benefit point...going beyond this will start to get really expensive.

    Anthony
     
  6. SethH

    SethH Cinematographer

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    In addition to the recommendation above, you should put weatherstripping around your exterior doors to make them as air-tight as possible. This will reduce the amount of noise leaking out and may save you a couple bucks on your heating/cooling bills.
     

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