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What part of the world are you in? I am in the midwest, so I am putting up 1" of foam insulation, with 1" air gap, then 2x4 stud will. That's just general wall construction in our area for a basement. If you want to do soundproofing you could decouple the walls with IB-3 clips or clips and hat channel. Then 2 layers of Type x 5/8" drywall with Green Glue between the layers. If do this with the IB-3 clips you are looking at around 6.75" to 7" from the foundation wall lost. If you do the clips and channel you will about about 1 1/4" or so.

Check out Soundproofingcompany.com for more information.
here a bit further north, i'm doing 2 in of foam insulation, 2x4 in front of that... fill with pink fluffy.

it's possible to do the ceiling and walls such that the ceiling is contiguous and sealed, but the walls don't need double drywall because that seal is kept on the ceiling... you essentially do the ceiling first, then drywall with double/gg... then the top plate of the wall is attached to the ceiling with IB3...
 

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What part of the world are you in? I am in the midwest, so I am putting up 1" of foam insulation, with 1" air gap, then 2x4 stud will. That's just general wall construction in our area for a basement. If you want to do soundproofing you could decouple the walls with IB-3 clips or clips and hat channel. Then 2 layers of Type x 5/8" drywall with Green Glue between the layers. If do this with the IB-3 clips you are looking at around 6.75" to 7" from the foundation wall lost. If you do the clips and channel you will about about 1 1/4" or so.

Check out Soundproofingcompany.com for more information.
Thanks man. I'm actually being super conservative in the end and say that it will all take 10" from foundation wall. So that is 10+10(insulation for two sides)+125"(four theatre seats with loveseat)+30+30(aisles)= 17', which is the width of the foundation pour. Cutting it a bit close but I think it is ok.
 

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As an aside, I’m trying a new product from isostore for my new build... should be interesting if it works well... I’ll be able to use a combination of slightly different techniques than with hat and channel... the channel ends up being furring strips... it’s also slightly cheaper when ordering bulk from them too... anyway, good luck!

https://isostore.com/hushframe-raft-connector.html
Hello!
Thanks for this link. I'm about a month or two out from needing to buy the clips & channel to put up the ceiling and these seem interesting. Would you mind posting about your experience?

Thanks!
 

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Hello!
Thanks for this link. I'm about a month or two out from needing to buy the clips & channel to put up the ceiling and these seem interesting. Would you mind posting about your experience?

Thanks!
I will do that shortly! I should be installing this weekend or next depending on how work goes... full steam ahead for me currently with work, so not a lot of time to make progress.... the shipment and ordering was great, and the customer quality seems good so far... I ordered 325 of them for my roughly 750 sq. Ft basement project. I need to get a build thread going one of these days. The principle is the same as hat and clips... instead of rubber and metal channel, these are bonded with a rubbery compound... theoretically they have even more damping material between the structural element and furring strip, but the big reason I want this route was ease of installation... I can screw the right to the side of my joists to get a 1/4” gap to the drywall... to do that with hat and clips would take blocking all over the place, all cut to different lengths, etc... (joists are twisted and uneven ). I’ll get some pics as I go through it and maybe Crete a dedicated thread for these...

I won’t be able to comment on how well they work vs hat/clips, but I’m hopeful they are “good enough” given my other compromises.

Thanks for asking!

And the prebuilt boxes (I got 4 for atmos speakers ) are very nicely built!
 

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Has anyone ever built speaker backer boxes and just glued them in place on the top piece of drywall, then put it up in place as one unit? Seems a lot easier than a separately suspended box. I would add more clips in the area around it. But, maybe the weight would still be too much?
A quick, back of the napkin calculation shows a 12"x12"x6" deep backer box with 2 layers of plywood or drywall will weigh about 13-15Lbs. On a ceiling, drywall screws are spaced 12" apart when they go into studs, so each screw is supporting about 2Lbs. Strictly from a weight standpoint, you could make an argument for 6-8 extra screws to support the backer box weight. I think the bigger question is whether or not the extra weight will cause the drywall to sag.

It's not too hard to support your backer boxes on the back side (the side opposite from where the drywall mounts) of the hat channel. That way the drywall and backer box will move together and you will not have to worry about sag or screws pulling out. I'm not sure if screw spacing is different when you are screwing into 25g hat channel.

Mike
 

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A quick, back of the napkin calculation shows a 12"x12"x6" deep backer box with 2 layers of plywood or drywall will weigh about 13-15Lbs. On a ceiling, drywall screws are spaced 12" apart when they go into studs, so each screw is supporting about 2Lbs. Strictly from a weight standpoint, you could make an argument for 6-8 extra screws to support the backer box weight. I think the bigger question is whether or not the extra weight will cause the drywall to sag.

It's not too hard to support your backer boxes on the back side (the side opposite from where the drywall mounts) of the hat channel. That way the drywall and backer box will move together and you will not have to worry about sag or screws pulling out. I'm not sure if screw spacing is different when you are screwing into 25g hat channel.

Mike



Yeah it might be more trouble than it's worth... getting it aligned right, and making sure you catch enough near by hat channel to add extra screws.



You're right, the easiest thing is to just bridge the top of the hat channel, but my problem is I am going to be recessing my clips and running the channel parallel to my joists. I am trying to lose as little ceiling height as possible. First layer of DW will only be about .300" below the original joists. ;)



I've come up with a way to mount the boxes. It can be done with an RS1c type bracket, but they're expensive and clunky. I am going to use small rubber isolation mounts mounted on right angle brackets. See my models attached. If anyone would like more details on this let me know. It works out a lot cheaper and I think a lot cleaner than using an RS1cDC04 type bracket.


In my situation, I am actually going to combine my speaker backer box and recessed light. Placement for me at least will work out ok, and I only have to mount 4 boxes.
 

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Has anyone got a link to construct the backer boxes? Been through a few threads tonight but not found anything yet. Seen the one of Bigs resting on the channel.
 

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Has anyone got a link to construct the backer boxes? Been through a few threads tonight but not found anything yet. Seen the one of Bigs resting on the channel.

Here is soundproofing company's write up. https://www.soundproofingcompany.com/wp-content/uploads/2011/06/CIM-backer-box-installation-web.pdf


They do OSB with cement board, GG in between. I suppose for fire code with can lights.


I'm doing MDF with 5/8DW, with GG. I figure the DW is fire rated, and I've seen others do it like this. I also feel like mdf with DW is denser for better soundproofing, that's just a guess though.
 

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double drywall + GG between the joist

Need some opinions on drywall between the joist in a room that is not going to be decoupled due to space limitation. All walls will just be double drywall and GG but the designer did mention i could do drywall between the joist for help with noise from the kitchen above. Should I be concerned about the weight of the drywall causing possible sag? Is it worth the effort? The kitchen is overhead but most of the time when watching movies nobody will be in there. When they are, its loud.
Thanks foe any recommendations.
john
 

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I feel like one layer and decoupling is better than two layers and no decoupling. Considering most of the sound transfer is through vibrations, which will be directly from the drywall to the joist to the upper floor. But i'll let sound masters jump in.
 

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I feel like one layer and decoupling is better than two layers and no decoupling. Considering most of the sound transfer is through vibrations, which will be directly from the drywall to the joist to the upper floor. But i'll let sound masters jump in.
Thanks for sharing!
 

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I feel like one layer and decoupling is better than two layers and no decoupling. Considering most of the sound transfer is through vibrations, which will be directly from the drywall to the joist to the upper floor. But i'll let sound masters jump in.
I asked this question to the Soundproofing Company: "I was thinking of decoupling the walls with IB-3 clips and using clips and channel on the ceiling with two layers of 5/8" drywall. NO GREEN GLUE. Would be decoupling and adding the second layer of drywall help without the Green Glue? Or should I just build it like a normal room with one layer of 5/8" drywall. Trying to save where I can."

They recommend that if you're on a budget, just stick with fiberglass insulation and double 5/8" Type X drywall. If you skip the Green Glue, I'd skip the clips also.

So I am leaning toward just using two layers of 5/8" Type X drywall. The extra mass in the second layer will help more then the decoupling. Guess it depends on your budget. By skipping Green Glue and clips/channel I can put the money towards other things.
 

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I was more concerned with footfall above, which the clips reduce greatly. So that's why I did clips and one layer. clips and two layers would have made the ceiling too low for me.
How much height did you reduce with the clips and one layer?
I also really want to know if the double drywall between the hoist is worth it?
 

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I was more concerned with footfall above, which the clips reduce greatly. So that's why I did clips and one layer. clips and two layers would have made the ceiling too low for me.
How much height did you reduce with the clips and one layer?
I also really want to know if the double drywall between the hoist is worth it?
I mean 5/8” plus GG. But my ceiling is super low and I can’t afford much.
 

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How much height did you reduce with the clips and one layer?
I also really want to know if the double drywall between the hoist is worth it?
There are ways to reduce the height loss by going between the joists more work but it can be done. If you go fully under the joist you are looking at about 3" with clips, channel, and 2 layers of 5/8" drywall.

Re DD between the joists I will share my experience. I did not do this and in my scenario, the theater is under the mstr bath/closet not a huge deal. Having said that you can faintly hear foot fall from the bathroom tile floor. Knowing this if the theater is going to be under a high traffic area that has, or will have, tile/hardwood, etc I would seriously consider doing it. If I had to do over I would have done it.
 

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There are ways to reduce the height loss by going between the joists more work but it can be done. If you go fully under the joist you are looking at about 3" with clips, channel, and 2 layers of 5/8" drywall.

Re DD between the joists I will share my experience. I did not do this and in my scenario, the theater is under the mstr bath/closet not a huge deal. Having said that you can faintly hear foot fall from the bathroom tile floor. Knowing this if the theater is going to be under a high traffic area that has, or will have, tile/hardwood, etc I would seriously consider doing it. If I had to do over I would have done it.
Thanks! Looks like ill be doing it.
 

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drywall in stud cavity to add mass?

Hi y'all,
I'm soundproofing what was formerly a garage space. The exterior wall has cedar plank on the outside face, so doing double drywall isn't an option as its outdoors.

What I'm wondering is if I could add a layer of 5/8" drywall in between the studs inside the cavity? Then I'd put in the insulation and add isolation clips/hat channel, 2 layers of 5/8" drywall with green glue for the wall inside the room.

Is there any reason this would be a bad idea? I'd lose a little bit of the air space in the cavity, but would still have about 4" between the inner and outer drywall layers.

Any other ideas how to add mass on that outside wall? The room isn't really big enough for double stud.

Thanks!
 
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