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Soundproofing a set?

Discussion in 'Scenery, Props, and Rigging' started by beachcombah15, Feb 14, 2009.

  1. beachcombah15

    beachcombah15 Member

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    Hey guys, just trying to gather some ideas over the weekend before I got back to school (during our weeklong february break) and put the finishing touches on our competition play. With that, we have built a totally off the hook set that has to be able to fit through a normal door frame and must be loaded in fro m the wings of any theatre in 5 minutes.

    At this point the only problem that still hasn't been resolved is how loud the noise factor when walking up the ramps that we have built leading up to our midpoint platforms which are also very loud. The ramps were built out of a 4' by 8' by 1/2" sheet of OSB and framed by 2 by 4's. And basically the same deal with the platforms.

    I had the idea to tack on foam insulation right under the OSB to help absorb the sound of the actors feet. Does this seem like a plausible idea? The only reason that this is a pretty major thing is that the pieces are actually supposed to be poured concrete...and the last time I checked, concrete is NOT hollow.

    Thanks for any and all
     
  2. DaveySimps

    DaveySimps CBMod CB Mods Premium Member

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    You might want to try 1/4" Masonite on top of the platforms. This helps to deaden the sound. Underside insulation works well. I have always used normal household fibergalss insulation for that (your typical Owens Corning stuff).

    ~Dave
     
  3. museav

    museav CBMod CB Mods Departed Member

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    That may help with some resonance and the hollow sound, although I would use fiberglass batts for that purpose rather than foam insulation, but ti will probably do little to reduce the actual footfall noise. That will take some combination of stiffening, such as doubling up on the plywood, and/or damping. For the latter you might want to try some of the damping materials like DynaMat that they sell in the car stereo sections at electronics stores, applying that to the bottom may reduce the impact noise.
     
  4. Footer

    Footer Senior Team Senior Team Premium Member

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    You need to hit is on two sides. First, put a layer of homasote on the top of the OSB, then add a layer a 1/4" maso for the walking surface. If that does not get rid of most of the noise, add carpet padding to the underside of the platform.
     
  5. beachcombah15

    beachcombah15 Member

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    I realize that using fiberglass batts would be ALOT better. BUT, my director insists on not using fiberglass because she's of it falling, getting on people etc as its a traveling set. So i guess what I'm asking is, would the foam have any affect on it?
     
  6. museav

    museav CBMod CB Mods Departed Member

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    A negligible effect, as would carpeting. Look at this, Commercial Acoustic Systems: SelectSound® Black Acoustic Board, it's a semi-rigid fiberglass board that is also black, great for many theatre applications. They also make a standard batt version, alos black.

    Is the problem more a 'thud' or the initial physical impact, like the clicks from high heels? A simple and inexpensive treatment for the latter is to cover the walking surface with carpet or carpet tiles, even thin carpet can help.
     
  7. beachcombah15

    beachcombah15 Member

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    It's more of a thid. The only problem with putting some kind of layer on top such as carpet is that it has already been painted and grafitti'ed, bottom line, I would be digging my own grave if I suggested to the powers that be to put a layer on top...
     
  8. icewolf08

    icewolf08 CBMod CB Mods

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    For future reference: Platform=Giant drum. Sound deadening is generally something that people build into platforms at the outset.

    In your case, remove the plywood lid, add a layer of Homasote or Celotex and put the lid back on top. You may need to re-cut your legs to account for the extra height, but it should help deaden the noise.
     
  9. BillESC

    BillESC Well-Known Member Premium Member

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    Acousticfirst Corporation offers the solutions you are searching for.

    This product is a sound blocker featuring 1" of foam with an 1/8" barrier and a 1/4" decoupler.

    [​IMG]
     
  10. beachcombah15

    beachcombah15 Member

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    Good thing it wasn't my set design! And better yet, nobody that has the power to, is willing to order any of this stuff! They always find an excuse as to why we can't order this or that! I hate it when people ask you to do something but don't give you the right tools for the job!!
     
  11. bobgaggle

    bobgaggle Well-Known Member

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    Cheapest best solution ever.... have the actors walk the ramps on their toes. Just walk toe heel (it can look natural) and it'll be a lot quieter. maybe rubber coat the soles of their shoes (if its a hard sole)
     
  12. museav

    museav CBMod CB Mods Departed Member

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    Just wanted to point out that impact noise, structureborne noise, airborne noise isolation and airborne noise absorption are all different things. You can convert one into another, e.g. structureborne noise can become airborne noise, and a source may generate more than one type of noise, but you often have to address these quite differently and materials made for one purpose may be quite ineffective at others, for example a soft, lightweight material may absorb noise and make the space under the platform less reverberant but it would provide little airborne noise isolation and have little or no effect on structureborne noise.

    Your situation sounds like an impact (footstep) causing structureborne noise that is then radiated as airborne noise into an area below where it reverberates. Typically the most efficient approach in any noise reduction effort is to start at the noise source, in this case to reduce the initial impact with carpet, soft heels, reducing the actual impact of the footsteps, etc. Next in line would be reducing the structureborne noise resulting by approaches such as stiffening the platform construction, adding intermediate supports to reduce the span and so forth. After that comes making the conversion from structureborne noise to airborne noise less efficient, for example applying damping materials to the bottom of the structure. Then reducing the reverberant nature of the area under the platform via fiberglass or other highly absorptive finish materials. The last step might be to try to contain or isolate the noise from the listeners, but that sounds a bit impractical in this situation.

    Because you may not be able to do any one treatment in a manner to sufficiently address the entire problem by itself, it may take some combination of treatments.
     
    kicknargel and (deleted member) like this.
  13. themuzicman

    themuzicman Well-Known Member

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    Try using homasote to tack on to your platforms. To further the noise, over the homasote, tack down a layer of muslin or canvas.

    Homasote is a great way to block out a lot of noise for cheap!
     
  14. museav

    museav CBMod CB Mods Departed Member

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    I'll just say that my view differs on that but I've now seen several references to Homasote when Homasote is a company that offers a range of products from roof decks to flooring underlayments to wall construction materials to fabric wrapped panels to materials to lay over ice surfaces. Homasote is a brand and not a specific product. In this case I'm not sure if it is Sound Barrier 440 or 4-Way Floor Deck or ComfortBase being referenced.
     
  15. themuzicman

    themuzicman Well-Known Member

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    From Wikipedia:
    Homasote is a type of wallboard similar in composition to papier-mache, made from recycled paper that is compressed under high temperature and pressure and held together with a glue. It is 1/2 inch thick and comes in sheets 4 by 6 feet

    [​IMG]

    That is a picture of the sheets that have been referred to homasote in two different shops I have worked in.
     
  16. hsaunier

    hsaunier Active Member

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    Just a thought. Consider spraying a treatment of self expanding foam insulation underside. Would have sound dampening porperties and should be able to withstand the traveling aspect of the set piece. Also consider placing a baffel across the middle of the underside, creating two smaller resinating boxes instead of one large one.
     

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