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Discussion Starter · #1 ·
I want to use 3/4 Birch Plywood for the Floor of the Stage with 2x4 16" on center studs.



Do I need to put another sheet of 3/4" Plywood below the stage??????


2nd Question. I plan on LIQUID NAILING the Stage on the floor. Is this a good IDea?



Final Question. Should the stage touch any of the 3 walls it will be set up to????




Thanks You



Abe
 

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Birch plywood is a little overkill. Regular plywood is fine and I would use 3/4 inch then 1/2 THEN 3/4". 3 layers on top. The bottom just needs some roofing felt 30 lbs. Glue and screw EVERYTHING is the rule of thumb. I would NOT let it touch the walls. I in fact, COATED the outside of my 2x6's with acoustic sealant to decouple them from the walls.


Greg
 

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Discussion Starter · #3 ·
What if I put 3/4 Plywood on the floor, stud 2x4 for fram, and another layer of 3/4 plywood on top. The walls have already been completed. How would I but the stage againts the wall?




Abe
 

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Here is a cheap and easy alternative for decoupling.....There is a roll of foam insulation that is used for sill plates on manufactured housing. Cost about $3.00 a roll....Big roll, you can use double runs....I just rolled out this stuff, cut it -glue it on if you feel the need.....This seals the space between the stage & wall - since it gives and takes - plus decouples it nicely.....I used this for the back and bottom - effectively decoupling it from the wall and floor......


Of course, this may be a terrible idea :) but it seems to work nicely....


Dave
 

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The reason you want multiple layers on the top of the stage is to make it stiff and heavy to limit sound transmission through the stage floor into the space below. For even more weight consider using MDF in place of plywood, and possibly using gypsum board sandwiched between two layers of MDF. You may also want to use roofing felt in the sandwich to help limit sound transmission down through the stage floor.


You don't want that space under the stage to like a resonating chamber (such as a guitar's body). In addition to the multiple layers for the stage floor, you should put either fiberglass insulation or better yet sand, inside the stage to absorb any sound leaking into the stage structure. Note the amount of sand required is very heavy so if the HT room is not in the basement or on a slab, make sure the floor can handle the weight of all that sand.
 

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Quote:
Originally posted by settopguy
Note the amount of sand required is very heavy so if the HT room is not in the basement or on a slab, make sure the floor can handle the weight of all that sand.
Speaking of which.....How is everyone buying their sand and hauling it to your basement? Does it come in bags (like 50lbs)? Roughly, on an average sized stage, how many pounds are we talking and what is the apx cost?
 

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I'm new to this, so be nice ---


my question is about the sand --- if possible, why not use concrete, and build the stage out of concrete? You could pour the stage at the same time as the concrete floor and walls. Help me if I am confused. Okay, I am confused.
 

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robertmee,


My stage is about 24' X 5' and built on 2X12's. I'm in the process of putting it together now. The estimated amount of sand to fill it is seven tons. The cost of that sand in the form of dry 100lb bags is $2000, whereas the cost of washed "mason's" sand in bulk is about $200. I went for the bulk sand (duh), but drying it out in my climate is not going well.
 

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Jmanthy,


$2000?!? Holy Crap!


If it comes to that much for dry playground sand, I'll stick with insulation. Even $200 bucks seems high :(


At 100lbs a bag (quickly does math in head), that's 140 100lb bags. If you think I'm carrying 140 100lb bags down stairs to my basement, you've got to be kidding :(
 

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At 100lbs a bag (quickly does math in head), that's 140 100lb bags. If you think I'm carrying 140 100lb bags down stairs to my basement, you've got to be kidding !!!





well, that is why I asked about concrete.


Concrete could be pumped at the same time as the floor and/or walls. I'm thinking about pouring concrete walls for my HT, to keep sound in, and to make the room very quiet.


Any opinions?
 

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Does concrete resonate?
 

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Consider dividing the stage into two or three parts. If you know you'll be placing the sub on the far left side of the stage, section off that left 1/3 or 1/4 and fill it with sand. Space the rest of the stage a bit away from this small sub platform so it's de-coupled and fill the balance with insulation.


If the surface is covered with carpet, there's not enough contact to carry the vibration from the sub platform, and you'll avoid any resonance with thye use of the insulation.


Ted
 

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pocatello,


If you are going to the expense of concrete walls I would look into structural insulated panels (OSB laminated to foam) They may have better sound qualities and would make nice straight walls. They can even be ordered with sheet rock already installed. Has anyone out there use them for a theater or know how they would perform?
 

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Hey magelsen, what is OSB and structural insulated panels? I have not heard those terms.


Thanks
 

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Pocatello,

OSB = Oriented Strand Board sometimes called wafer board. it is the material you commonly see as sheeting on exterior of new construction homes.


The structural panels are made of 2 skins of OSB laminated under pressure to a core of foam (I belive polystyrene). the panel comes in different sizes and thicknesses. They have high insulation factors for the given thickness as there are no (or minimal depending on design) studs to transfer noise or energy from one side of the panel to the other as with standard construction. In addition, the panels are stronger than conventionally constructed walls. The thicker panel are also used for floors and roofs. The panels can be manufactured to spec. and generally include vertical and horizontal chases in the foam to act as conduit for wiring. Several companies manufacture them the one I remember off hand is R-Control. I visited one of their plants several years ago in Phoenix. Heres an address if you are interested.
www.rcontrol.com


Ben
 

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Ben ---


thanks for the link. It was helpful information.
 

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Why does the stage need to be decoupled from the side walls?


Does this apply to a raised seating platform as well? About to build mine and dont wanna screw it up.
 
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