# Soundproofing in a 2nd floor theater



## Upstairs Cinema (May 18, 2010)

Hello again all,

Most builds on here are basement builds, with very few exceptions. I am hoping to do the full Clips/DD+GG on my walls and ceiling (so much for headroom lol) but im not sure about the floor. Most have cement, and im obviously dealing with Joists. Due to flanking i figure if im gonna do all the rest i may as well do the floor. Whats the best method?

Just another 3/4" plywood layer with GG over the existing subfloor?

Are there clips to decouple the plywood subfloor from the joists?


This is gonna cost me a fortune :/ But I've been looking into the Klipsch THX Ultra 2 speaker setup, and I think soundproofing will be very necessary, if not for my house, for my neighbors lol.

Cheers


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## bpape (Sep 14, 2006)

On the floor, there are a couple of things you can do. 

U-Boats (or equivalent) spaced on the joists below the floor and then laying 2 layers of subfloor over that will certainly help. There is some disagreement over the effectiveness of the U-Boats but I've had good luck with them - not to mention giving you a little additional depth in the gap of the ceiling below.

As with anything else, the more mass, the better in terms of subfloor.

If you're going to have your speakers and sub on a stage, then you will also want to decouple that from the floor to help minimize direct transfer to the floor structure from the sub(s). Filling the stage with sand will help a lot but you'll want to make really really sure that the floor will hold the weight. Might want to bring in a structural engineer.

Bryan


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## Ted White (May 4, 2009)

Good question. You'll have to do something with the floor. 

"Are there clips to decouple the plywood subfloor from the joists?"

Does this mean you have not laid the subfloor yet? You could install joist isolators on the joist tops, then float double OSB subfloor (with damping) on them.


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## Upstairs Cinema (May 18, 2010)

Thanks bpape, Ill look for those U-boats. 

Honestly, I dont think im gonna have space for a stage. Just gonna have a screen wall with the speakers all behind it. 8' ceilings be moo :/



Ted White said:


> Good question. You'll have to do something with the floor.
> 
> "Are there clips to decouple the plywood subfloor from the joists?"
> 
> Does this mean you have not laid the subfloor yet? You could install joist isolators on the joist tops, then float double OSB subfloor (with damping) on them.


The house is complete, but i will pull up what floor is there if needed and just replaced with thicker stuff.


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## Ted White (May 4, 2009)

Ha! We're all online at the same time!

Per Bryan's comment about these isolators, they are good to deploy on top of the joists. There are other applications where they are not best deployed, but in your case, they're fine.


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## tonyvdb (Sep 5, 2007)

Placing the speakers and sub on some sort of raised platform really helps with sound transfer. It does not have to be high even 6" would be enough.


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## bpape (Sep 14, 2006)

If no stage, you might want to consider something like a Sub-Dude or equivalent. That's just basically a small platform that helps decouple the sub from the structure.

Bryan


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## Upstairs Cinema (May 18, 2010)

Theres something called a Sub-dude?? LOL :rofl:

I have shrank my huge screen aspirations from 142 to 126, but with the carada Masquerade screen frame + Clips on the ceiling and extra flooring, there isnt a whole lot of room to play with. Was hoping to lay the subs horizontally under the screen. Its a sealed box, so im hoping it wont fail miserably if an inch or so of the woofers is behind the Carada frame. WTB 9' ceilings.

THanks for the replies all! You guys are fast!


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## tonyvdb (Sep 5, 2007)

How far back from the screen will you be sitting? 126" may actually still be too large for your viewing distance.


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## Upstairs Cinema (May 18, 2010)

Front row is a hair over 10'6" back. Probably too big for most, but its a 16:9 screen. In 2.40:1, its only 120, and is OK. Since most movies nowadays are 2.40, I am going for the larger 16:9. We've been sitting 10'6" away for a few weeks now, and its actually just fine at 134", but it just doesnt look like the room is there for it in the end.

We prefer the immersive theater experience. Back row viewing of a 92" screen is very 'meh' to me.


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## tonyvdb (Sep 5, 2007)

10 feet back and 126" (16:9 at 110") is going to be a bit uncomfortable, most dont go larger than 96" at that distance. You will find that you will be missing some of the action on the sides viewing that large. But in the end its all about what you want and like.


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## Upstairs Cinema (May 18, 2010)

Yea i hear ya, I get that alot. I must have better peripheral vision than most or something, cause I have no issues seeing the whole thing at once.

At any rate, I'll look into the U-Boats, OSB, and sub-dudes. Thanks all


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## Upstairs Cinema (May 18, 2010)

Actually, since i've already started the topic, Tedd I have a question for ya. I was reading on your site about a dedicated floating floor, and it states that it raises the floor 4 3/4". How would one handle this regarding entry into the room? Just a raised door jamb? Not sure if there are code requirements with that. If i can afford a 7" overall loss between floor and ceiling, that seems like a pretty nice setup. 

Looks like it would cause a triple leaf effect though, with the 2x OSB --> space to original subfloor --> Space in joists to the ceiling below.


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## Ted White (May 4, 2009)

Different application compared to what Bryan and I were describing. Stand by for incomming transmission of a graphic that describes better...


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## Ted White (May 4, 2009)




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## bpape (Sep 14, 2006)

Good diagram of the stud isolator method. 

Note that the 2 layers of OSB run perpendicular to each other.

Bryan


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## Ted White (May 4, 2009)

It's hard to see that, but yes they do. Also, this floating floor isn't suitable for load bearing construction. You should run this by the building inspector, if you've pulled a permit.

If you had double layers of 3/4" T&G OSB, you would use 1 1/4" screws to cinch the two panels together. You cannot screw back to the original joists.


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## Upstairs Cinema (May 18, 2010)

Thanks Ted! I didnt see any rubber isolators for anything larger than 2x6. Floors are 2x10 i believe? 
Unless non-load bearing is very strict, i dont see it as too much of an issue. Build inside the existing walls, the only thing it would hold is a false screen wall and the riser/seats.


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## Ted White (May 4, 2009)

The isolators fit on the 2x dimension, so 2x4, 2x6, 2x10... doesn't matter. It fits them all


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## Upstairs Cinema (May 18, 2010)

Ted White said:


> The isolators fit on the 2x dimension, so 2x4, 2x6, 2x10... doesn't matter. It fits them all


LOL, doesnt that show the day im having? 

/feels like an idiot.


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## Ted White (May 4, 2009)

No worries.


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## Upstairs Cinema (May 18, 2010)

Ted White said:


>


I havent checked my local codes on this, but how does one deal with the floor once it goes up 3"? The door has to be moved up and a 3" landing built? I imagine some sort of sill would need to be built to seal the floor height difference between two rooms.


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## Ted White (May 4, 2009)

The floor would normally go up 3/4" with standard subfloor. In addition to this, you would have anoter 3/4" subfloor and 1/2" for the rubber joist isolator. There's no code for the height of the floor, but you would accomodate this height difference with something like a small step, or a gradual rise in the floor outside the room (like on the hallway sub-floor)


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## dusnoetos (Jun 1, 2010)

I have worked in commercial construction for a number of years. I have seen a number of methods for sound soundproofing a room. One of the most effective methods I have seen for both floors and walls is a laminate design. (from bottom up) ¾ OSB, ¾ drywall, Lightweight Vinyl Sound Damping Sheet  1" MDF, and a carpet of your choosing with a thick pad. The key here is mass. Sure this method is very pricey but very effective in my opinion. Of course you will want to have the OSB, dry wall and MDF overlapping by at least 2 feet. 
I have know idea if the building inspector would squawk at this method (the building inspector on the job we used this method was actually impressed) - but I guarantee that this method is very strong. (just make sure your floor joists can handle the extra weight.) Also - as far as I am concerned - this is your house - you do to it what you want. And if you do it right no one would be the wiser. 
Well that is just my 2¢


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## Upstairs Cinema (May 18, 2010)

dusnoetos said:


> I have worked in commercial construction for a number of years. I have seen a number of methods for sound soundproofing a room. One of the most effective methods I have seen for both floors and walls is a laminate design. (from bottom up) ¾ OSB, ¾ drywall, Lightweight Vinyl Sound Damping Sheet  1" MDF, and a carpet of your choosing with a thick pad. The key here is mass. Sure this method is very pricey but very effective in my opinion. Of course you will want to have the OSB, dry wall and MDF overlapping by at least 2 feet.
> I have know idea if the building inspector would squawk at this method (the building inspector on the job we used this method was actually impressed) - but I guarantee that this method is very strong. (just make sure your floor joists can handle the extra weight.) Also - as far as I am concerned - this is your house - you do to it what you want. And if you do it right no one would be the wiser.
> Well that is just my 2¢


What do you mean by overlap at least 2'? Lost me there. Heres the gig. Completed 2nd floor. I dont have an upstairs hallway, but more a 6' wide by 19' open space with doors all around it. If i pad up the theater floor inside the decoupled walls and seal with caulk, id imagine it will do well. the problem lies in mating the higher floor with the hallway outside. It will make for a really awkward outer hallway area (im also flipping the theater door to swing out into the hall, since there is a ton of room). it may end up just being a compromise of soundproofing and being able to practically mate it to the rest of the house. Wish i could just have the door swing out 3" above the hallway floor and have ppl step up into the jamb, but i think code is against that.

Yea pricey is the word, of my whole build, I have a feeling trying to treat walls will be 3/4 of the budget. Ill have to build the shell, and then save for the equipment at this rate.


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## Ted White (May 4, 2009)

Upstairs Cinema said:


> Wish i could just have the door swing out 3" above the hallway floor and have ppl step up into the jamb, but i think code is against that.


Per my dimensions above, the height difference would be 1 1/4", not 3"


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## Upstairs Cinema (May 18, 2010)

Ted White said:


> Per my dimensions above, the height difference would be 1 1/4", not 3"


Yea that was in response to stacking drywall and more plywood and all.


Have you heard anything about the Homosote 440 or w/e its called? Is that stuff worth it, or is GG between the plywood layers more than enough?


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## dusnoetos (Jun 1, 2010)

Just make a slight slope and paint it bright orange so people see it.

What I mean by over laping... you do not want the seams of the boards to match up.

How loud do you plan to have your system? If you listen loud enough to bother your neighbors you may be damaging your hearing. How close are your neighbors? Will there be other people in the house that would be bothered by the sound when you are watching a movie? In other words Do you really need to go through this much work? I assume this room will have no windows. that in and of its self should be enough to isolate the sound from your neighbors. (unless they are only a 10 or less feet apart.) As for the floor, you may be surprised how much damping a nice thick carpet with a double pad would provide (plus is so nice to walk on). I also agree with some others - decoupling the subs makes a big difference. 

I don't mean to sound critical. I have just seen a number of people build a home theater and just go way over board on the project - spending way more $$ than needed. But if you require complete sound proofing be prepared to shell out the money.

Something else I just rememberd... If you can get a decent damping from spray on foam insulation. See here http://www.thefoampros.com/sounddeadening.html


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## Upstairs Cinema (May 18, 2010)

dusnoetos said:


> Just make a slight slope and paint it bright orange so people see it.


:rofl:


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## Ted White (May 4, 2009)

Upstairs Cinema said:


> Yea that was in response to stacking drywall and more plywood and all.


There's no need for more than what's in the diagram




Upstairs Cinema said:


> Have you heard anything about the Homosote 440 or w/e its called? Is that stuff worth it, or is GG between the plywood layers more than enough?


The product won't do anything in this application


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## Upstairs Cinema (May 18, 2010)

Ted White said:


> There's no need for more than what's in the diagram
> 
> 
> 
> ...


Excellent. I will plan for joist isolators, and an extra sheet of drywall with GG. If anything that helps preserve height since id like to use clips on the ceiling. Thanks a ton Ted 

At only 1 1/4", id just have ppl step up into the jamb /shrug


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## Ted White (May 4, 2009)

Upstairs Cinema said:


> Excellent. I will plan for joist isolators, and an extra sheet of drywall with GG. If anything that helps preserve height since id like to use clips on the ceiling. Thanks a ton Ted
> 
> At only 1 1/4", id just have ppl step up into the jamb /shrug


Extra sheet of subflooring, not drywall...


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## Upstairs Cinema (May 18, 2010)

Ted White said:


> Extra sheet of subflooring, not drywall...



Yar, 3/4", thats what I meant... :/


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## dusnoetos (Jun 1, 2010)

dusnoetos said:


> Just make a slight slope and paint it bright orange so people see it.
> 
> Something else I just rememberd... If you can get a decent damping from spray on foam insulation. See here http://www.thefoampros.com/sounddeadening.html


Yes the slope statement was a "slight Joke". In a commercial application you would have to do something like that.


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## Ted White (May 4, 2009)

The ramp would only need to be 1 1/4", so if you have enough space outside the theater, the rate of rise isn't too bad.


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## Ted White (May 4, 2009)

dusnoetos said:


> Something else I just rememberd... If you can get a decent damping from spray on foam insulation.


Not to be critical, but foam really has no place in a sound isolated environment. It does not damp, and results are much better with simple fiberglass in the stud or joist cavities. I'm sure that seems counter-intuitive, but true nonetheless.


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## Upstairs Cinema (May 18, 2010)

My only aversion to a ramp of any kind would be that it would be across the opening of the hall. So if someone wanted to go to the restroom from a bedroom, there would be something to trip on in the hall unless they remembered/went around.

I need a WATCH YOUR STEP mat in front of the door that is a 1" thick padded rug lol.


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## MatrixDweller (Jul 24, 2007)

I just thought I should mention that if the floor has already been laid it could be glued and screwed down. That will present quite the challenge to pull it up and would most likely damage the tops of the joists. Locating the joists, drilling big holes and blowing insulation in might be a lot easier. Then green glue a couple layers on top of it.


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## tjambro (Jan 16, 2007)

Ted White said:


>





bpape said:


> Good diagram of the stud isolator method.
> 
> Note that the 2 layers of OSB run perpendicular to each other.
> 
> Bryan


I agree, Ted has a lot of cool diagrams! :T


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## chiltown (Jun 29, 2010)

If you are going to use wood flooring, use cleats instead of staples. Likewise, consider lots of area rugs.


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## Ted White (May 4, 2009)

For the reduction of footfall impact, I'm much more of a believer in the carpet and pad than I am with exotic pads that do the same thing. When we talk about membranes and composites, under carpet, I think of great waste.


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## getech (Mar 4, 2010)

uild ceiling and walls. Soundproofing walls essentially amounts to making them thicker, although not necessarily denser. Sound can be dampened when it is forced to move through several layers of material at different densities, so it is in your best interest to create these layers. There are two main methods to go about this, both of which can use your existing walls.
Use soundproofing compound (notably, Green Glue). This is a magical substance which converts sound energy to heat energy, effectively absorbing the sound rather than simply dampening it. It is applied like caulk and can be used to essentially laminate an existing wall or ceiling. This is a good option if you do not have the space to expand a wall or ceiling out several inches. [1] It can also be used in combination with the second method, however.
Use double walls and drop ceilings. The other option is to use thicker walls and ceilings. Build a basic wall frame and attach it to your existing surface, anchoring it to the existing studs. This will be covered with a new layer of either drywall or sheetrock (the lighter the materials the better, with ceilings). You can leave simple empty space in the new gap or you can fill it with soundproofing insulation. Finish the new wall in whatever way you want or add soundproofing panels.


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