Quieting Down the HT room

Discussion in 'Home Theater Projects' started by Jeremy.H, Sep 9, 2005.

  1. Jeremy.H

    Jeremy.H Auditioning

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    My wife and I just bought a new house and we're planning on turning part of our unfinished basement into a home theater room. The place where we want to put the room at is about 12ft x 16.5ft. Three walls are already studded and 2 already have insulation. We'll have to stud the last wall.

    I know right now from reading posts on here I'm going to put in a floating floor and use an insulated exterior door. However I'm not sure what to do for the walls. I've seen people use normal insulation or acoustic panels. I'd like to do as much as I can to dampen the vibration and sound, while keeping it cost effective.

    I'm open to suggestions, recommended products or vendors.

    Thanks in advance,
    Jeremy
     
  2. chris_everett

    chris_everett Second Unit

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    First of all, it's important to separate the two relevant areas of accoustics that your talking about

    1. Accoustical Treatment. I.E. the stuff that makes your theater sound better.

    2. Accoustical Isolation. I.E. the stuff that keeps the sound _in_ your theater.

    Isolation must be dealt with during construction, so I'll talk about that first.

    There are three keys to making a soundproofed room

    1. Airtight. Your already addressing this with the exterior doors, but it's also important to seal any seams in the drywall, around boxes, etc. It's important to make sure that your door threshold is truly airtight. The air in and out of your theater should be limited to the actual ventilation ducts. (Due to the twists and turns in ducting, along with the air flowing through them, sound coming through ducts is usually minimal)

    2. Dense wall partitions. This can be accomplished with multiple layers of drywall, mass-loaded vinyl (MLV), mineral fiber insulation (normal "pink stuff" insulation is poor, but it's better than nothing). Dense wall partitions take more energy to move and vibrate

    3. Separation, or "de-coupling". Room within a room construction is the best example of this. Your addressing some of this with the floating floor, and if you can build a second set of walls on it, and build a ceiling on top of that you would have a near completely isolated room. Short of that, products like resilient channel, and even foam tapes can make a big difference.

    Although we say "sound-proof" we should really say "sound-resistant" The amount of sound that your willing to allow to leak is the biggest factor in how much time and money you want to invest. I used a foam tape on my studs, dual drywall, MLV, some mineral fiber around "weak" spots, and you can't tell I'm watching a movie in 90% of my house. Only in the immediately adjacent rooms can you tell something is playing.

    That brings us to accoustical treatments.

    There are many commercial products available to help you, or you can make your own. The basic goal is to reduce or eliminate reflections of sound. Because of the number of speakers in a theater, we want to be in the "near-field", that is, hearing only the direct sound of the speakers. Accoustical foams and panels, bass traps, and the like are all used. Remember that the lower the frequency, the more difficult it is to absorb sound. I used accoustical foam on my ceiling, and a strip around the walls at ear level.

    A couple of recommended sites:

    www.soundproofing.org Information and products, related(surprise) to soundproofing. The site looks weak, but the info, products, and people are very good.

    www.auralex.com Information and products mostly related to accoustical treatment. Their primary market is studios, but the information and products are useful to anyone.

    www.realtraps.com Information and products mostly related to accoustical treatment. An alternative type of product to the foam that auralex offers. Run by Ethan Winer, probably one of the best minds in the industry, and an occasional contributor here

    http://www.ethanwiner.com/basstrap.html Ethan's home page has some info on how to build your own version of his "pro" absorbers here.
     
  3. Jeremy.H

    Jeremy.H Auditioning

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    Thanks for the informative reply. I checked out the websites and I'll be spending some money at soundproofing.com for sure.

    Where is the best place to get mineral insulation?

    Thanks much,

    Jeremy
     
  4. chris_everett

    chris_everett Second Unit

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    I ordered mine from auralex, but I don't know that I'd call them the "best" place for that. If you can get it locally, I would.
     
  5. SteveLeach

    SteveLeach Stunt Coordinator

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