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post #1651 of 2427 Old 08-31-2016, 12:59 PM
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Thanks, just to clarify on some points.

So the leak came from my fridge (upper floor) and leaked down to the basement, damaging a lot of my blu ray collection and then the water also followed a soft bendable vent which caused the damage in the soundproofed room. Special note: dont buy or use fridges that have the water/ice function. the contractor that came to assess and try to minimize damage informed me that a high number of their water damage calls are related to this type of issue.

So yes, the sheets are staggered in order to cover the joining gaps. obviously now when the repair work is done, i will lose that staggering. I will be ordering some acoustical sealant to cover those seems this time around.

so the leak must have been going on for approximately 12 hours. I then cleaned everything up and the company came in order to place de-humidifiers and fans to dry as much as they possibly could. the DW on the other side of the wall, dried completely fine, however the double DW still shows high humidity after 2 days of drying. the way he explained it to me, is he thinks water got stuck in between the 2 sheets and is just sitting there, so this is why they want to break it down. And yes, we will also be removing and replacing the insulation that has gotten wet. were not taking any risks.

back to my original question though, the reason why i was asking, they are coming tomorrow to tear down the walls. it is the workers that are affiliated with my insurance company, the same ones that have setup the fans and de-humidifiers.
I am certain they have never had to tear down DW setup of this kind. I know the screws will need to come out for sure, but will they need to break and crumble all the drywall around the screws? I used quite a bit of screws. they cant just rip it off the way they would normally do.
I dont have any experience in demolition, this is a first for me. I will be there to supervise them, I just want to make sure they dont cause any damage to the existing channels.

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Originally Posted by HT Geek View Post
Sounds like you don't have a choice but to remove screws. I'm not sure why you'd be averse to that either.

Anyway, are your sheets mis-aligned so the seams are not lined up? Presuming the seams are staggered (they should be), it will be easier for you to have the 4x8, 4x6 sections cut out and then put back the drywall in those places without worrying about the seams. Just live with it for that section being non-optimal is my suggestion. Less work and chances are it won't make any difference with regards to sound-proofing (just be sure to caulk the seams around the new DW pieces). And me personally, I would make the 4x6 a 4x8. Two fewer drywall sheets to cut.

What is the source of the water leakage? And how long was your DW wet before the problem was discovered?

You may need to remove insulation behind the damaged area, depending on how long it's been wet and whether or not the moisture has been fully mitigated. Since it sounds like you have not yet removed the affected drywall, IMHO you should plan on replacing any insulation behind it as well. Unfortunately, insulation is a good harbor for mold growth after it's been saturated. That's presuming you have 'pink fluffy' behind the DW. If you have Roxul you may fare better. Maybe not. I'd replace any insulation period. All the insulation manufacturers claim their products don't promote mold growth. And they don't. However, water does and anything attached to the insulation (e.g. wood, dirt, paper facing, etc.) will promote mold growth. Trust me, I've been down that road (drywall in basement flooded for 2 weeks due to hurricane and I was on vacation at the time).

Bottom line: I know this is a big P.I.T.A. for you atm, but you will have to deal with an even bigger problem long-term if you don't act aggressively to mitigate the issue as soon as you can. Also why it's important to clarify the cause of the damage.
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post #1652 of 2427 Old 09-01-2016, 06:01 AM
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Originally Posted by skads_187 View Post
so the leak must have been going on for approximately 12 hours. I then cleaned everything up and the company came in order to place de-humidifiers and fans to dry as much as they possibly could. the DW on the other side of the wall, dried completely fine, however the double DW still shows high humidity after 2 days of drying. the way he explained it to me, is he thinks water got stuck in between the 2 sheets and is just sitting there, so this is why they want to break it down. And yes, we will also be removing and replacing the insulation that has gotten wet. were not taking any risks.
That's good. You'll be fine.


Quote:
back to my original question though, the reason why i was asking, they are coming tomorrow to tear down the walls. it is the workers that are affiliated with my insurance company, the same ones that have setup the fans and de-humidifiers.
I am certain they have never had to tear down DW setup of this kind. I know the screws will need to come out for sure, but will they need to break and crumble all the drywall around the screws? I used quite a bit of screws. they cant just rip it off the way they would normally do.
I dont have any experience in demolition, this is a first for me. I will be there to supervise them, I just want to make sure they dont cause any damage to the existing channels.
Explain to them they need to use a Drywall saw, Saw-zall, or similar tool to cut out the sheets because they are glued, screwed, and staggered. They may need to poke around a bit to verify where the columns of screws are. A magnet sometimes works to identify where they are without damaging the drywall, if you/they have one handy.

Your insurance company is obligated to pay for repairs and "like-kind" replacement. Technically, you could argue they need to re-do the entire wall because the wall won't be completely staggered when they are done - as you've pointed out. Personally, I would live with it as long as they take care to minimize the damage in the demo process and someone takes ample acoustic caulk to the seams when the pieces are replaced.

If they are resistant, I would not let them do the work, call your insurance adjuster and bitch.
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post #1653 of 2427 Old 09-01-2016, 06:05 AM
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One more thought... normally, under state law you have the right to choose the contractor. If you hired a particular company to build the walls in the first place, I'd strongly consider/suggest hiring that company to fix your wall. And in that case, you may consider re-doing the whole wall after all to preserve the staggered pattern. You'd need to negotiate that with your insurance company first of course, but your original contractor could vouch for the construction method and provide an expert opinion on why the entire wall needs to be re-done (and possibly the soffit as well). If you line that up, they can't say no (if they do, you can sue them and file a complaint with your state Attorney General's office, and your state insurance comptroller.... insurance companies don't like to get letters from those folks).

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post #1654 of 2427 Old 09-01-2016, 07:06 AM
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Quote:
Originally Posted by HT Geek View Post
One more thought... normally, under state law you have the right to choose the contractor. If you hired a particular company to build the walls in the first place, I'd strongly consider/suggest hiring that company to fix your wall. And in that case, you may consider re-doing the whole wall after all to preserve the staggered pattern. You'd need to negotiate that with your insurance company first of course, but your original contractor could vouch for the construction method and provide an expert opinion on why the entire wall needs to be re-done (and possibly the soffit as well). If you line that up, they can't say no (if they do, you can sue them and file a complaint with your state Attorney General's office, and your state insurance comptroller.... insurance companies don't like to get letters from those folks).
so yes, I will be actually getting my own contractor, so at the same time I can help explain exactly how to put it back together.
but at the same time, I will leave the current workers complete the destruction part of it, because they want to make sure that there is no more water left anywhere.

So far, as far as I am concerned, they will be giving me exactly the same products/quality that Ive had before, but that is to be seen in the next few days when the quotes for repair will be submitted.

just an FYI, im in Canada and not in the US.
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post #1655 of 2427 Old 09-01-2016, 07:18 AM
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Originally Posted by skads_187 View Post
so yes, I will be actually getting my own contractor, so at the same time I can help explain exactly how to put it back together.
but at the same time, I will leave the current workers complete the destruction part of it, because they want to make sure that there is no more water left anywhere.
Makes sense. I forgot the mitigation phase is independent of the re-construction phase.


Quote:
just an FYI, im in Canada and not in the US.
Ah... well, I'm sure Canada has some sort of rules on the subject. Sounds like you are on top of it.

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post #1656 of 2427 Old 09-01-2016, 07:53 AM
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Quote:
Originally Posted by HT Geek View Post
Makes sense. I forgot the mitigation phase is independent of the re-construction phase.




Ah... well, I'm sure Canada has some sort of rules on the subject. Sounds like you are on top of it.
I hope so lol, im just a bit frustrated that they need to redo the whole flooring in the whole basement, and I will now need to undo everything i just recently did. a real pita, but i guess it could have been worse, they just better give me the money I need to replace my blu-rays!
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post #1657 of 2427 Old 10-30-2016, 07:41 AM
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Question

Guys, looking to greatly reduce noise moving through a small wall (~8H x 6W)... where the prior owner built the wall with only a 1" gap between it and the HVAC/Furnace/Blower

The blower & furnace sounds/vibrations go directly through the wall.

Access between the wall and furnace is VERY difficult but I was thinking I may be able slip one or two of these panels between to stop the noise... at less cost/effort vs redoing (or even just adding GG + Mass to) the wall. I will be remodeling in 10-12 months so this is a stop-gap but I don't want to spend money if it will not really work.

Anyone ever use Quilted Fiberglass Panels for sound mitigation? I might be able to get these pretty inexpensively...
Singer Safety Sound Stopper 4'W - 1" Thick Double Faced Panel - SC-123
-- http://www.singersafety.com/catalog/...erglass-panels

And I was also thinking I might hang some MLV since I have a spare 4x8 roll

Interested in anyone having experience with doing anything like this?

Thx!

________
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setup: Kodi, Paradigm-Velodyne-SVS, 120" DIY Spandex Screen, Sony 45ES
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post #1658 of 2427 Old 10-30-2016, 01:45 PM
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I am a novice in the area of soundproofing but have been reading everything I can get my hands/eyes on. I am concerned about whether modifying my original approach to soundproofing my listening space in a more cost effective manner will result in a failed effort.
My sound system is on the lower level of our home. My wife uses the living room directly above my listening space. She can't hear the TV or speak on the phone when I hit higher volumes with my system.
We are seeking sound reduction, not sound proofing.
I intend to close off the open listening space with an attractive glass wall (has STC rating in the mid 50's) which will reduce much of the vocals and higher frequencies from traveling up an open staircase into the living room area.
Heavy Crestron (Rose Co.) drapes will be hung in front of the glass wall.
The plan is to tear out the ceiling and stuff it with Roxsul them install a channel system.
It seems side to side noise is not an unlivable situation as my wife can make a phone call in the next room when the system is played loudly. So noise and vibrations traveling upstairs is my issue.
I spoke to a rep from one of the soundproofing websites who suggested not going the full distance on the walls as well as the ceiling. He felt a majority of the benefit to soundproof the upstairs area would be realized by doing the ceiling properly. Perphaps adding another layer of wallboard with Green Glue right over the existing wallboard would suffice and save me money?? I have seen some benefit from blowing dense insulation into the walls can add some STC value as well.
I am open to suggestions.
Thanks.
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post #1659 of 2427 Old 10-30-2016, 06:26 PM - Thread Starter
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Quote:
Originally Posted by Livin View Post
Guys, looking to greatly reduce noise moving through a small wall (~8H x 6W)... where the prior owner built the wall with only a 1" gap between it and the HVAC/Furnace/Blower
The blower & furnace sounds/vibrations go directly through the wall.

Access between the wall and furnace is VERY difficult but I was thinking I may be able slip one or two of these panels between to stop the noise... at less cost/effort vs redoing (or even just adding GG + Mass to) the wall. I will be remodeling in 10-12 months so this is a stop-gap but I don't want to spend money if it will not really work.

Anyone ever use Quilted Fiberglass Panels for sound mitigation? I might be able to get these pretty inexpensively...
Singer Safety Sound Stopper 4'W - 1" Thick Double Faced Panel - SC-123
-- http://www.singersafety.com/catalog/...erglass-panels

And I was also thinking I might hang some MLV since I have a spare 4x8 roll
The proper solution to this would be to add mass and more mass plus try to decouple that wall as much as possible. The latter definitely falls into a "remodel" perspective, though, not a stop-gap.

In general I wouldn't assume that those fiberglass panels would help in the way you'd hope. Those fall under the absorption umbrella which is the weakest of all the soundproofing types. There's a reason the website says that they should be used in conjunction with other noise control solutions and also refuse to give any sound ratings for the 1". There's simply not enough of it to affect anything but the higher frequencies.

MLV isn't often recommended just because it's very expensive for what you get, compared to solutions like drywall+GG and the like. But it absolutely does work and if you already have it, by all means hang some up and see how much it helps! That'll help far more than the fiberglass solution would.

Now... you did say that you could get the fiberglass sheets inexpensively. If so, then it might be worth getting a few panels of those and combine those with the MLV. I can't guarantee any specific amount of noise reduction but you'd certainly get something.
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post #1660 of 2427 Old 10-30-2016, 06:38 PM - Thread Starter
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Quote:
Originally Posted by BP View Post
I am a novice in the area of soundproofing but have been reading everything I can get my hands/eyes on. I am concerned about whether modifying my original approach to soundproofing my listening space in a more cost effective manner will result in a failed effort.
My sound system is on the lower level of our home. My wife uses the living room directly above my listening space. She can't hear the TV or speak on the phone when I hit higher volumes with my system.
We are seeking sound reduction, not sound proofing.
I intend to close off the open listening space with an attractive glass wall (has STC rating in the mid 50's) which will reduce much of the vocals and higher frequencies from traveling up an open staircase into the living room area.
Heavy Crestron (Rose Co.) drapes will be hung in front of the glass wall.
The plan is to tear out the ceiling and stuff it with Roxsul them install a channel system.
It seems side to side noise is not an unlivable situation as my wife can make a phone call in the next room when the system is played loudly. So noise and vibrations traveling upstairs is my issue.
I spoke to a rep from one of the soundproofing websites who suggested not going the full distance on the walls as well as the ceiling. He felt a majority of the benefit to soundproof the upstairs area would be realized by doing the ceiling properly. Perphaps adding another layer of wallboard with Green Glue right over the existing wallboard would suffice and save me money?? I have seen some benefit from blowing dense insulation into the walls can add some STC value as well.
I like that you differentiate "sound reduction" from "sound proofing" since, well, that's all we can really do anyway. The only true sound proofing is to build a theater in space -- everything else is just reduction.

The Soundproofing Company used to have a pretty comprehensive page on the different ways of treating ceilings but I can't find it anymore. Their new page is much more limited but still useful:

https://www.soundproofingcompany.com...oof-a-ceiling/

Note how much of a dramatic difference adding the channels makes and then bumping it up significantly again just by adding more mass in the joist bays themselves. Having two sets of two layers of drywall/wallboard with GG on each side of a decoupled connection can make a difference far outstripping what the simple material additions suggest.

Anything beyond what is suggested in their SPC Ceiling Solution 3 tends to be cost prohibitive and/or requires notable remodeling (e.g., floating ceilings and the like).
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post #1661 of 2427 Old 10-30-2016, 08:13 PM
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Hi granroth:
Appreciate your response.
Yes, looks like SPC2 or SPC3 is the ceiling solution I need. Do I understand correctly that the difference are the boards placed in the rafters against the upstairs floor? And this is a way to reduce footsteps, etc from above disturbing the listening space below? If so, I am OK with SPC2 because noise from above is not an issue.
I was planning on removing the ceiling board, stuffing something like Roxsul in the rafters then adding a clip and channel solution to remount 2 layers of ceiling wallboard on.
Is this similar to SPC2?
I am also interested in your opinion about treating the walls to get some benefit but without removing them. I guess adding mass would help; such as 2 layers of wallboard with Geeen Glue. Should any insulation be blown into the walls also? Will doing this type of treatment to the walls help reduce transmission of noise or vibrations to the living room above my listening space?
Thanks!!
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post #1662 of 2427 Old 10-30-2016, 11:09 PM - Thread Starter
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Quote:
Originally Posted by BP View Post
Yes, looks like SPC2 or SPC3 is the ceiling solution I need. Do I understand correctly that the difference are the boards placed in the rafters against the upstairs floor? And this is a way to reduce footsteps, etc from above disturbing the listening space below? If so, I am OK with SPC2 because noise from above is not an issue.
I was planning on removing the ceiling board, stuffing something like Roxsul in the rafters then adding a clip and channel solution to remount 2 layers of ceiling wallboard on.
Is this similar to SPC2?
The difference between SPC2 and SPC3 is, indeed, the two sheets of drywall+GG installed between the rafters. The website stresses their importance for footfall traffic but that's only because that's the focus on ceilings that they are promoting. They will absolutely help even in your case and by a pretty significant amount -- witness the rise from 66 STC to 76 STC with the addition of those layers. It's worth noting that STC doesn't measure anything at all like footfall traffic and thus that increase of 10 STC is all about reducing the sound coming from your theater to the room above.

So what it comes down to is that if you absolutely cannot install those extra sheets (or even one more sheet, which would give you 72 STC) then you will still be getting a very excellent score of 66... but if you do have the access and the time money and will to install them, then the upgraded solution will be even better!

And yes, your existing plan is pretty much SPC2, as long as you are using Green Glue between the two layers and are using 5/8" Type X drywall (or the equivalent, if different locally). Your results will be dramatically different if you skip the Green Glue step or if you use 1/2" or "lightweight" drywall.

Quote:
Originally Posted by BP View Post
I am also interested in your opinion about treating the walls to get some benefit but without removing them. I guess adding mass would help; such as 2 layers of wallboard with Geeen Glue. Should any insulation be blown into the walls also? Will doing this type of treatment to the walls help reduce transmission of noise or vibrations to the living room above my listening space?
Ah, this is where it gets a little more nebulous and harder to predict measurable results. What you'd be attacking by treating the walls would be the "flanking" problem. This is where sound will travel up the studs in your walls and travel through the joists to the floor above, completely bypassing all of our soundproofing efforts. Flanking can absolutely be a huge problem and is a leading cause of soundproofing efforts not delivering the results that you expect.

But... it's hard to predict in advance just how much a problem a specific flanking case will make! You could forgo treating the walls and discover that your expected sound attenuation was far below what was expected... or skip treating them and find that it made no difference in the end. Likewise, you could treat them and have them make no difference (although you wouldn't know).

The issue is that we're in full chaos theory mode trying to track all of the variables that would come into play in order to predict the outcome of those connected pieces.

The end result is that it would never hurt to add a couple layers of DW+GG and if you can afford it, you won't regret it. But you won't know in advance if it's actually required or not.

As far as blown insulation goes... it's essentially not done in any typical professional soundproofing environment, as far as I know. I did see a video a few years ago comparing using densely packed cellulose vs fluffy fiberglass for soundproofing and the video showed a vast improvement with the blown material. In the real world, though, it doesn't appear to work that way. The mass of the material just isn't enough even densely packed to make any notable difference in that regard and the absorption isn't significantly better, either. Worse yet, the packed material will very often settle over time, leaving gaps in the coverage. That could dramatically diminish your attenuation over time.

That's why the standard recommendation is to just install batts of fluffy fiberglass. It holds its shape in filling the bay; is inexpensive; and does a good job of absorbing sound for its size. If you don't want to tear down your existing wallboard, though, then that wouldn't be an option.

Honestly, I wouldn't bother. The absorption part would mostly come into play with sound traveling through the wall and would have little effect to sound traveling up the wall. You've already said that side-to-side sound isn't a problem and so I don't think you'd notice any difference one way or another. It would be the added mass and damping that would prevent the sound from getting to the studs in the first place, thus reducing your flanking.
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post #1663 of 2427 Old 10-31-2016, 01:01 PM
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Hi granroth:
I think I am starting to get a handle on this effort. Shortchanging the wall effort may defeat my entire goal if low frequencies find their way up the walls and around the treated ceiling. So the walls will have to come down. Too bad but likely worth it in the long run.
I decided to call The Soundproofing Co today and spoke at length with Ted. What a knowledgeable guy who enjoys sharing his expertise. I am now comfortable with the concept of having my contractor work with Ted to obtain the needed results. My dealer who quoted big $ will not be so pleased...but our 40 year friendship will survive.
The ceiling rafters will be stuffed with insulation and then a clip and channel setup to attach the 2 layers of wallboard with Green Glue. The walls will either get a new staggered set of studs or S clip and channel setup.
The most interesting part of our discussion was about a glass wall to close off the listening space. It appears Ted has potentially provided a much more cost effective solution for me to use that will provide a significantly higher STC value. The dealer solution has an STC in the mid 50's. Ted thinks his solution will get me into the 70's. Further research to come and I hope, confirm this estimate.
Does it seem I am on the right path?? Hope so! I am so enjoying learning about this aspect of audio.
Thanks!!
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post #1664 of 2427 Old 11-03-2016, 12:02 AM
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Below are a few pictures of my soon to be theater. I am building this along with my brother, and being in Alaska, our resources are limited for this type of information, so this site has been very helpful with planning. I'm just hoping I'm not getting to the point of overthinking everything!

The front screen wall (turret) and one of the main side walls is 8" ICF. The other main wall is a 2X6 bearing wall and I've built a 2X4 wall next to it for separation, so I've got about 9" of depth. My back wall is 2X4 framed, and my ceiling is 12" floor joists. The level above the ceiling (main dining room) is plywood with 1&1/2" of gypcrete. The floor is a concrete slab. I plan to stuff insulation into each wall, the second row seating platform and throughout the ceiling.

Basic room dimensions are 24' deep by 13' wide. The ceilings are 100" and I will be building a ~8"X16" soffit (mostly for looks) on all walls except the screen wall. The screen wall will be built 3'-4' out from the back of the turret and I will be using an AT screen with a shelf holding the front speakers and possibly the subs. I will either be installing a 5.2.4 or 7.2.4 Dolby Atmos system. The door is the only opening in the room, and I do have an air supply duct not too far from the door opening. In the first picture, you can see that I have also installed bracing between the floor joists to firm things up.

I'm looking for some guidance on how I should handle this room for some basic sound proofing. I know some of the basics from reading through these forums, but I'm hoping for some pointers specific to my setup. This room is in the basement and two stories below the main bedrooms.

On the bearing wall, I can't go much thicker than 1&1/4" of finished wall beyond where it currently is due to the door opening. What I do on the bearing wall I'd like to match on the rear wall since the door is centered at an angle between those two walls. Right now I'm thinking 1/2" OSB with 1/2" drywall, then install acoustic panels over the finished wall. Our drywall up here is about $18 per 4X8 sheet of 1/2", so the $21 per sheet of OSB isn't too much more and would give me a solid nailing surface for acoustic panels and any other treatments. I'm wondering if I going to have any sound issues due to 1/2 of the theater being ICF and the other half wood framed?

Thanks in advance!

Jerry
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Jerry
Fairbanks, Alaska
DIY In Progress Home Theater Build: http://www.avsforum.com/forum/19-ded...tic-build.html
Star Ceiling Build: http://www.avsforum.com/forum/19-ded...am-boards.html
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post #1665 of 2427 Old 11-03-2016, 09:49 AM
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Jerry,

I'll share my thoughts with you, FWIW.

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Originally Posted by arcticbowman View Post
... my ceiling is 12" floor joists. The level above the ceiling (main dining room) is plywood with 1&1/2" of gypcrete. The floor is a concrete slab. I plan to stuff insulation into each wall, the second row seating platform and throughout the ceiling.
How thick is the concrete of your dining room floor?


Quote:
The front screen wall (turret) and one of the main side walls is 8" ICF. The other main wall is a 2X6 bearing wall and I've built a 2X4 wall next to it for separation, so I've got about 9" of depth. My back wall is 2X4 framed, .... <snip> .... Basic room dimensions are 24' deep by 13' wide.... <snip> .... The screen wall will be built 3'-4' out from the back of the turret and I will be using an AT screen with a shelf holding the front speakers and possibly the subs.
The shape of your turret wall will give you a bit more interesting acoustics to sort out, relative to sound travelling from the sides and rear of your front side speakers. Just something to keep in mind. You can reduce the potential for issues with that by either very thickly padding those walls with absorption and/or choosing speakers with polar plots that show little rear/side reflections. That said, you might not even notice an issue. I'm just mentioning this because those walls will reflect sound and in your case they will provide non-right angles so it's going to make those reflections different than the norm. Maybe it will help out; I really don't know for sure (if one of the audio gurus here chimes in, then we'll know).


Quote:
.... The ceilings are 100" and I will be building a ~8"X16" soffit (mostly for looks) on all walls except the screen wall.... <snip> .... I do have an air supply duct not too far from the door opening.
HVAC vents: My advice... come up with a plan (before you install drywall) that 1) creates at least 2 supply vents in the room; 2) adds a return vent; 3) ensures equal air pressure in/out of the room; 4) allows for reduced velocity of air flow in and out of the room (<250 fpm); 5) places the vents where they are not in direct line of sight of the screen; and 6) supply vents are not near the PJ.

Soffits: 8" deep/tall is relatively short (mine are 10"). Presuming that is your outside dimension, that's about the minimum to fit HVAC flex duct of a reasonable width. Basically you won't be able to fit insulated HVAC flex duct any larger than 6" (add a minimum 2" for the insulation around it). You need insulated flex duct for supply vents. You can ditch the insulation wrapper for the return duct, so long as it is insulated for a few feet before entering any unfinished space (e.g. attic). Just going between floors in your home, you could likely get away with un-insulated. What happens if there's an issue? Condensation. Water where you don't want it. This is only an issue if you have significant temp differences between air spaces. That is what the insulation is for (to prevent the coupling of these temperature differentials, such as cooled air in a hot attic.


Quote:
On the bearing wall, I can't go much thicker than 1&1/4" of finished wall beyond where it currently is due to the door opening.
That's fine. 2x 5/8" = 1-1/4"


Quote:
Right now I'm thinking 1/2" OSB with 1/2" drywall, then install acoustic panels over the finished wall. Our drywall up here is about $18 per 4X8 sheet of 1/2", so the $21 per sheet of OSB isn't too much more and would give me a solid nailing surface for acoustic panels and any other treatments.
After having built a room with 1x OSB (5/8") + 1x DW (5/8"), I recommend NOT doing that. Why? For one, it's a bigger PITA than hanging drywall. Second, at least in my case it created less even-ness (for lack of a better word)... let's say less uniformity of the 1st layer on the studs. What I ended up with were slight variations in various places. It essentially resulted in a little extra work to get the drywall layer nice and even, and smooth. The result was more time spent putting up the walls. I also caulked in between the 1st layer of OSB, which I recommend you do as well if you go that route (i.e. before you put the drywall over top of it). Also, be sure to have the SMOOTH side of the OSB facing INWARD - into the room (guess how I know not to use the rough side? LoL).

My alternative suggestion: Use an OSB backer for the 1st layer when you know you'll need to adhere something to the wall (such as a column), and you know that whatever it is will not be wide enough to straddle the studs. Another idea is to put horizontal cross-braces between the studs in these locations, but that obviously requires very accurate planning of where you will put nails or screws in the future. I also suggest using 5/8" OSB and not 1/2" to keep the thickness consistent with the drywall (plus it's more mass, which is good for absorption).


Quote:
I'm wondering if I going to have any sound issues due to 1/2 of the theater being ICF and the other half wood framed?
Maybe. What is on the other side of those walls, respectively?

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Originally Posted by HT Geek View Post
Jerry,

I'll share my thoughts with you, FWIW.



How thick is the concrete of your dining room floor?

- It is 1&1/2" gypcrete over the top of the plywood.


The shape of your turret wall will give you a bit more interesting acoustics to sort out, relative to sound travelling from the sides and rear of your front side speakers. Just something to keep in mind. You can reduce the potential for issues with that by either very thickly padding those walls with absorption and/or choosing speakers with polar plots that show little rear/side reflections. That said, you might not even notice an issue. I'm just mentioning this because those walls will reflect sound and in your case they will provide non-right angles so it's going to make those reflections different than the norm. Maybe it will help out; I really don't know for sure (if one of the audio gurus here chimes in, then we'll know).

- Interesting point on the rear and side deflections. I will take that into consideration when narrowing down the surviving speakers on my list. I believe only a couple of them have any side or rear ports.


HVAC vents: My advice... come up with a plan (before you install drywall) that 1) creates at least 2 supply vents in the room; 2) adds a return vent; 3) ensures equal air pressure in/out of the room; 4) allows for reduced velocity of air flow in and out of the room (<250 fpm); 5) places the vents where they are not in direct line of sight of the screen; and 6) supply vents are not near the PJ.

Soffits: 8" deep/tall is relatively short (mine are 10"). Presuming that is your outside dimension, that's about the minimum to fit HVAC flex duct of a reasonable width. Basically you won't be able to fit insulated HVAC flex duct any larger than 6" (add a minimum 2" for the insulation around it). You need insulated flex duct for supply vents. You can ditch the insulation wrapper for the return duct, so long as it is insulated for a few feet before entering any unfinished space (e.g. attic). Just going between floors in your home, you could likely get away with un-insulated. What happens if there's an issue? Condensation. Water where you don't want it. This is only an issue if you have significant temp differences between air spaces. That is what the insulation is for (to prevent the coupling of these temperature differentials, such as cooled air in a hot attic.


- I'll discuss this with my HVAC guy (brother )




That's fine. 2x 5/8" = 1-1/4"




After having built a room with 1x OSB (5/8") + 1x DW (5/8"), I recommend NOT doing that. Why? For one, it's a bigger PITA than hanging drywall. Second, at least in my case it created less even-ness (for lack of a better word)... let's say less uniformity of the 1st layer on the studs. What I ended up with were slight variations in various places. It essentially resulted in a little extra work to get the drywall layer nice and even, and smooth. The result was more time spent putting up the walls. I also caulked in between the 1st layer of OSB, which I recommend you do as well if you go that route (i.e. before you put the drywall over top of it). Also, be sure to have the SMOOTH side of the OSB facing INWARD - into the room (guess how I know not to use the rough side? LoL).

My alternative suggestion: Use an OSB backer for the 1st layer when you know you'll need to adhere something to the wall (such as a column), and you know that whatever it is will not be wide enough to straddle the studs. Another idea is to put horizontal cross-braces between the studs in these locations, but that obviously requires very accurate planning of where you will put nails or screws in the future. I also suggest using 5/8" OSB and not 1/2" to keep the thickness consistent with the drywall (plus it's more mass, which is good for absorption).


- Great ideas, thank you. I'm still wondering if going 5/8 vs 1/2 really yields that much more of a benefit when double layering. I think more than anything, I'm dreading having to haul more 5/8" rock down to the basement, I thought I was done with that! I am presuming I can get away with a single layer of 1/2" on the ICF walls.


Maybe. What is on the other side of those walls, respectively?

- On the other side of the ICF walls is dirt, this is a below grade basement with the top 3' or so is exposed to outside. The forms are ~2" foam on each side with 8" of concrete in the center and the foundation is a poured monoslab.


Opposite of the bearing wall is the main gathering area for the man cave. It's around a 700 square foot open area.


Opposite of the rear 2X4 wall is the bar which is around 120 square feet
.


Thank you very much for the input, I really appreciate it.


Jerry
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Jerry
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1. 1-1/2" thick gypcrete should be ~14 to 16 psf, if I recall correctly. Prolly closer to 14. Regardless, that is very dense when it comes to residential floors that are not on grade. That's good for this purpose, though concrete tends to conduct LF fairly well (a minus). With an air gap above a double-DW ceiling in your HT room, plus some insulation in there.... That ought to work well. Plus how often do you use your dining room anyway? Most people hardly ever use it.

2. My comments about speakers and their audio dispersion (polar plots) don't have anything to do with the ports. What I was referring to is every speaker has a pattern with which it disperses sound - in a 360 degree arc on each axis (x, y, z) - creating a sphere of sound projecting outward. The most intense/loudest sound comes of course in the front, where the speaker's sound-emitting portions are pointed. However, all speakers "leak" sound in other directions as well, such as from reverberations of the speaker cabinet, and just plain the way sound travels. My point was simply that some speakers are better than others at directing as much as possible of the sound/noise forward. Some are very "leaky" per se and tend to pump out more sound at different frequencies at other angles. You want to try and avoid the latter. The only way you'll know, however is by looking at polar plots.

And I want to add that this is really a micro attention to detail for most people. If you had your speakers right up against the wall, it might be a bigger issue. The only reason I mentioned this is because as I said above, the angle of your wall behind the front side speakers is going to direct those reflected sounds at unusual angles into the room. It could theoretically be something you want to deal with. However, if you have a lot of absorption behind and to the side of those speakers, I believe you'll have no issues. You may wish to consider using a baffle wall, as an example.

3. Is 5/8" better than 1/2" drywall? Yes. Is it a HUGE difference? No. You're talking less than a handful of STC points. That said, the more layers, the more the difference is amplified. If you don't need absolutely the best sound proofing then you'll likely be fine with the 1/2". I understand the motivation of not moving 5/8" sheetrock. The key is really to use a dampener in between - a viscoelastic compound; e.g. Green Glue, Quiet Glue, TiteBond, etc. (btw, don't use TiteBond).

Presuming a 2x4 wall cavity with wood studs, insulation in the walls, and the sheetrock attached directly to the walls (i.e. no clips & channel, etc.), the delta between 1x 5/8" sheetrock and 2x 5/8" sheetrock with no glue in between is 2 or 4 STC, depending on your source of info (i.e. who's test you're reading). The delta between 2x 5/8" with no viscoelastic glue and 2x 5/8" DW with Green Glue in between is 7-11 STC. If you use clips & channel + viscoelastic glue, the delta jumps to 20-23 STC (a SUBSTANTIAL difference).

4. I would recommend clips & channel at least on your common (interior) walls. Ideally, you'd have either a) complete room-within-a-room (double stud wall and independent [floating] ceiling); or b) clips & channels on all walls and ceiling. That would be your best isolation. If you like to play movies and music loud and your significant other hates that, this would be your best bet (including viscoelastic glue in between 2x DW layers on all surfaces). You could still skimp a bit and go with 1/2" sheetrock. The isolation offered by the clips & channel + viscoelastic glue will do more for you than the extra mass of the 5/8" drywall (though mass is a big helper in absorption).

If you don't blare your content super loud all the time, you could compromise and use more isolation for those common walls. It would save you time and money. Just depends on your priority. The biggest factor is it's obviously very difficult to re-do anything in the future if you feel you didn't do enough the first time around.

Many people on this forum will tell you to goto the max with isolation, but IMHO one needs to be practical if you're not an ADHD audiophile and this is your home. Like I said, it all depends on your priorities and needs/wants.

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I want to do some soundproofing in between my ceiling joist. I see it's best to do DD with GG. I will be using 5/8 DW. I can't get this in between every joist with the existing duct work installed. I have about 24 joist going across and I can get about 20 done leaving 4 that I can't get 2.

1)So should I still do the 20 or would I be wasting my time and money since I can't do them all.

2) can I not do the GG just double up on the drywall?
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Originally Posted by ncabw View Post
I want to do some soundproofing in between my ceiling joist. I see it's best to do DD with GG. I will be using 5/8 DW. I can't get this in between every joist with the existing duct work installed. I have about 24 joist going across and I can get about 20 done leaving 4 that I can't get 2.

1)So should I still do the 20 or would I be wasting my time and money since I can't do them all.

2) can I not do the GG just double up on the drywall?
I understand your conundrum, but it's a bit of a loaded question as you put it above. By that I mean - for example - if your room's ceiling is attached to the structural ceiling joists, then what you are proposing will have a minimal benefit because sound will travel via the ceiling joists to which your drywall is directly attached.

Now, if let's say you have some sort of isolation (such as clips & channel) between your ceiling joists and your drywall ceiling, then at that point doing what you propose begins to become more effective as you are blocking some of the sound traversing through the open cavities in the ceiling between the joists.

All that said, if you still want to consider implementing your plan, a diagram would be helpful for other folks to ascertain the potential effectiveness. Photographs would be even better. Some folks on AVS will tell you it's an all-or-nothing proposition, but I personally believe the devil is in the details. There are some cases where not having 100% of the joists dampened might not be a big deal. So, if you have photos or a diagram, please share so that we can do a more thorough job of advising.

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Originally Posted by HT Geek View Post
1. 1-1/2" thick gypcrete should be ~14 to 16 psf, if I recall correctly. Prolly closer to 14. Regardless, that is very dense when it comes to residential floors that are not on grade. That's good for this purpose, though concrete tends to conduct LF fairly well (a minus). With an air gap above a double-DW ceiling in your HT room, plus some insulation in there.... That ought to work well. Plus how often do you use your dining room anyway? Most people hardly ever use it.

With the ceiling I think I will do a single layer of rock using the clips and channel, stuff the 12" cavity with insulation and call it good. With the added plywood and gypcrete on the dining room level, I'm keeping my fingers crossed that it will be sufficient. I also think I will go a little larger on the soffit. Right now we have it at 8" high by 16" deep, however the last 6 of depth" is going to be a channel for rope lights. I may lower it a couple inches to 10". I don't think I will be doing much more with HVAC in that room. I have a 4X10 supply line to feed the room with a little fresh air, but we hardly use the HVAC.

2. My comments about speakers and their audio dispersion (polar plots) don't have anything to do with the ports. What I was referring to is every speaker has a pattern with which it disperses sound - in a 360 degree arc on each axis (x, y, z) - creating a sphere of sound projecting outward. The most intense/loudest sound comes of course in the front, where the speaker's sound-emitting portions are pointed. However, all speakers "leak" sound in other directions as well, such as from reverberations of the speaker cabinet, and just plain the way sound travels. My point was simply that some speakers are better than others at directing as much as possible of the sound/noise forward. Some are very "leaky" per se and tend to pump out more sound at different frequencies at other angles. You want to try and avoid the latter. The only way you'll know, however is by looking at polar plots.

And I want to add that this is really a micro attention to detail for most people. If you had your speakers right up against the wall, it might be a bigger issue. The only reason I mentioned this is because as I said above, the angle of your wall behind the front side speakers is going to direct those reflected sounds at unusual angles into the room. It could theoretically be something you want to deal with. However, if you have a lot of absorption behind and to the side of those speakers, I believe you'll have no issues. You may wish to consider using a baffle wall, as an example.

Thank you for the further explanation on this. I'm wondering if it would be safest to drape velvet directly over the styrofoam of the ICF to keep the hard surfaces at bay. I do need to darken it up back there. I will have about 8" of the angled turret remaining in front of the screen once the screen wall and speaker shelving is built. I could build a baffle wall on each side to eliminate the angles, but I'm thinking that could cause odd deflection as well. Maybe it's just one of those things I should leave well enough alone.

3. Is 5/8" better than 1/2" drywall? Yes. Is it a HUGE difference? No. You're talking less than a handful of STC points. That said, the more layers, the more the difference is amplified. If you don't need absolutely the best sound proofing then you'll likely be fine with the 1/2". I understand the motivation of not moving 5/8" sheetrock. The key is really to use a dampener in between - a viscoelastic compound; e.g. Green Glue, Quiet Glue, TiteBond, etc. (btw, don't use TiteBond).

Presuming a 2x4 wall cavity with wood studs, insulation in the walls, and the sheetrock attached directly to the walls (i.e. no clips & channel, etc.), the delta between 1x 5/8" sheetrock and 2x 5/8" sheetrock with no glue in between is 2 or 4 STC, depending on your source of info (i.e. who's test you're reading). The delta between 2x 5/8" with no viscoelastic glue and 2x 5/8" DW with Green Glue in between is 7-11 STC. If you use clips & channel + viscoelastic glue, the delta jumps to 20-23 STC (a SUBSTANTIAL difference).

I think I'm sold on the double dry wall with clips and channel. I do need to get educated more on how to properly do the clips and channel, so I will research that some. I'm sure a search in this thread will yield something educational for me, but if you know of a specific thread or search that I should do, I would appreciate it. I will plan to do this on all of the wood framed walls. I'm scratching the OSB idea, so my final dilemma is 1/2" vs. 5/8". Unfortunately the basement is finished too much to bring down 12' sheets anymore, but I'm not overly upset about that.

4. I would recommend clips & channel at least on your common (interior) walls. Ideally, you'd have either a) complete room-within-a-room (double stud wall and independent [floating] ceiling); or b) clips & channels on all walls and ceiling. That would be your best isolation. If you like to play movies and music loud and your significant other hates that, this would be your best bet (including viscoelastic glue in between 2x DW layers on all surfaces). You could still skimp a bit and go with 1/2" sheetrock. The isolation offered by the clips & channel + viscoelastic glue will do more for you than the extra mass of the 5/8" drywall (though mass is a big helper in absorption).

If you don't blare your content super loud all the time, you could compromise and use more isolation for those common walls. It would save you time and money. Just depends on your priority. The biggest factor is it's obviously very difficult to re-do anything in the future if you feel you didn't do enough the first time around.

Many people on this forum will tell you to goto the max with isolation, but IMHO one needs to be practical if you're not an ADHD audiophile and this is your home. Like I said, it all depends on your priorities and needs/wants.

We have a very open design on our house, so I'm thinking I better do the sound control right the first time around. I'm at the stage where it is easy to do, so I don't want to be kicking myself later on down the road.
Thanks again for all of your assistance! Obviously you've got an open invite to check out the theater when it's completed. Decent excuse for a trip to Alaska, don't ya think?

Jerry
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Quote:
Originally Posted by ncabw View Post
I want to do some soundproofing in between my ceiling joist. I see it's best to do DD with GG. I will be using 5/8 DW. I can't get this in between every joist with the existing duct work installed. I have about 24 joist going across and I can get about 20 done leaving 4 that I can't get 2.

1)So should I still do the 20 or would I be wasting my time and money since I can't do them all.

2) can I not do the GG just double up on the drywall?
Yes, it's all just a matter of degrees and wether or not a solution meets your requirements. If you are expecting X results but your solution just provides Y, then you'll be disappointed. But if you only expected Y from the start, then anything more is overkill.

Let's start with the fact that doing anything is going to be measurably better than doing nothing. Filling 20 of 24 joist bays will absolutely make a difference as that will attenuate a significant amount of sound energy. Some will absolutely flank around the treated bays into untreated ones but very possibly not enough to bother you.

Likewise with using drywall without GG. The additional mass is the bulk of the benefit anyway and the GG just adds an extra "kick" with its damping. I've always put GG in the "very nice to have if you can afford it" category vs the "must install" like extra mass.

Let's take a step back, though... why are you wanting to treat the inside of the joist bays? Is this just an extra step in addition to the primary treatment of the ceiling itself? If it's a standalone treatment then... well, it will certainly do something but it does get less likely that it'll do enough to satisfy what you have in mind. Handling the joists bays is traditionally the last little bit done to eek out the final bits of performance out of a comprehensive solution and almost never done standalone.
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Yes, it's all just a matter of degrees and wether or not a solution meets your requirements. If you are expecting X results but your solution just provides Y, then you'll be disappointed. But if you only expected Y from the start, then anything more is overkill.

Let's start with the fact that doing anything is going to be measurably better than doing nothing. Filling 20 of 24 joist bays will absolutely make a difference as that will attenuate a significant amount of sound energy. Some will absolutely flank around the treated bays into untreated ones but very possibly not enough to bother you.

Likewise with using drywall without GG. The additional mass is the bulk of the benefit anyway and the GG just adds an extra "kick" with its damping. I've always put GG in the "very nice to have if you can afford it" category vs the "must install" like extra mass.

Let's take a step back, though... why are you wanting to treat the inside of the joist bays? Is this just an extra step in addition to the primary treatment of the ceiling itself? If it's a standalone treatment then... well, it will certainly do something but it does get less likely that it'll do enough to satisfy what you have in mind. Handling the joists bays is traditionally the last little bit done to eek out the final bits of performance out of a comprehensive solution and almost never done standalone.
Your your points. Next year I'm tearing out the ceiling of an already finished basement (prior owner did it). Hoping the below plan gets me the 80/20 rule on 'cost & effort' vs 'benefit' to isolate footfall/impact sound (main concern) and sound leakage from HT into living-room above (secondary concern)

Current plan...

1. Leave the current, standard, 1/2" DW walls - doing nothing new
2. Replace the stairwell hollow core door with solid core. Stairwell is folded, so sound must turn 90 degrees to get both in and out of the room, so it is already darn good attenuation even with doors open
3. Tear out all of existing the ceiling
4. Replacement ceiling:
a. add 5/8" DW between joists, a much as possible... not every cavity is possible due to vents/wiring - not planning to use GG
b. add 2x4 cross bracing between joists to increase joists 'stiffness'... thinking less flex = less vibration
c. hang 5/8" DW/GG/DW on basic clips/channel
d. install roll insulation in all joist cavities where possible (not possible to in vent cavities)
e. build DW/GG/DW "boxes" for the 4 atmos ceiling speakers
5. Thick drapes/window coverings over windows & glass doors
6. a few (minimal) absorption and dispersion DIY panels on walls/ceiling (no idea where these will go until the room is complete)

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post #1673 of 2427 Old 11-04-2016, 10:55 AM
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granroth and other knowledge ones:
I am finally giving up on this process. It appears I will be wasting my money.
As granroth suggested leakage will be an issue. And make me feel the effort was wasted.
I think the world of Ted White. After digging into my project he advised me that "holes" created by frames of large sliding glass doors and a stairwell would negate all my planned soundproofing efforts, including an expensive glass wall.
Just adding a layer of wallboard to increase the mass will be all I should try.
He didn't even suggest GG!
So I guess I am revising my objective to deal more with mid and high frequencies.
Not sure if it's stil worth Roxsuling the ceiling and even 1 rear wall anymore.
Count me as depressed!!
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granroth and other knowledge ones:
I am finally giving up on this process. It appears I will be wasting my money.
As granroth suggested leakage will be an issue. And make me feel the effort was wasted.
I think the world of Ted White. After digging into my project he advised me that "holes" created by frames of large sliding glass doors and a stairwell would negate all my planned soundproofing efforts, including an expensive glass wall.
Just adding a layer of wallboard to increase the mass will be all I should try.
He didn't even suggest GG!
So I guess I am revising my objective to deal more with mid and high frequencies.
Not sure if it's stil worth Roxsuling the ceiling and even 1 rear wall anymore.
Count me as depressed!!
bp


I can attest personally to the fact that simply stiffing multiple layers of SafeNSound does very little to reduce sound transmission. I've had to completely rebuild the room and isolate tonget good results


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post #1675 of 2427 Old 11-04-2016, 12:18 PM
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Puzzled by my options....

I am a long time lurker and done a ton of reading here but I still have a few questions. I am in the planning stages of my theater and struggling with soundproofing. Most of my problems result from the width of my room. It is rather narrow, being a couple of inches shy of 12 feet from foundation wall to interior wall. On the foundation wall I was planning 2 inches of foam insulation, a one inch gap, a 2x4 wall (stuffed with insulation) and two sheets of 5/8 drywall with GG. I figure right there I am losing almost 8 inches. I live in a cold climate so don’t want to lose the insulation and the foam doubles as a vapor barrier. The opposing interior wall is pre-existing and follows a beam. It also hides the support posts. I can’t easily move it and would prefer not to lose space to clips and channel. I might be able to recess the clips into the wall on blocking but it is built on steel studs and I am not exactly sure how that would work. On the other side of the wall are my furnace room, bathroom, and games room. I don’t really care if some sound leaks to these spaces but would become concerned if it was enough to get picked up by the duct work or bleed substantially through the ceiling. I am not aiming for perfect sound proofing but enough that I can watch movies at a reasonable volume, while others sleep on the second floor. Having spewed all that background here are my questions:

1. Is it acceptable to frame the foundation wall on 2x3s, attached with IB-3 clips and have the insulation bridge the one inch gap to the foundation wall rather than use 2x4s and a one inch air gap?

2. On the interior wall if I just use IB-3 style clips, instead of clips and channel, would it block enough sound so as to not get picked up by the ducts? I can’t seem to find STC or other ratings for these clips. I am thinking of IB-3 clips, double 5/8 drywall with GG on the theater side and a single layer of 1/2 on the outside. These walls are already finished on the non-theater side but I think I can shorten them in place and install IB-3s. My gut is this is fine as it will still be much better than the door….

3. If the answer to number two is “No” is it acceptable to use clips and channel on the outside of the wall (inside the furnace room, bathroom, etc.)? I would rather not have to tear out and rebuild these walls but I could.

I am of course open to any other ideas that will help me achieve my goals of maximizing width and sound proofing. Thanks in advance for any advice.
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post #1676 of 2427 Old 11-04-2016, 01:41 PM
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Quote:
Originally Posted by healthnut View Post
I can attest personally to the fact that simply stiffing multiple layers of SafeNSound does very little to reduce sound transmission.
Just adding/clarifying that Roxul Safe'n'Sound has the greatest effect in 500+ Hz frequencies. If one wants more uniform absorption, Rockboard 80 comes to mind and it has a relatively consistent damping effect across the whole spectrum. That said, insulation is going to have the least significant impact compared to isolation, mass, etc. But it's not without merit.

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post #1677 of 2427 Old 11-04-2016, 02:22 PM
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Originally Posted by arcticbowman View Post
With the ceiling I think I will do a single layer of rock using the clips and channel, stuff the 12" cavity with insulation and call it good. With the added plywood and gypcrete on the dining room level, I'm keeping my fingers crossed that it will be sufficient. I also think I will go a little larger on the soffit. Right now we have it at 8" high by 16" deep, however the last 6 of depth" is going to be a channel for rope lights. I may lower it a couple inches to 10". I don't think I will be doing much more with HVAC in that room. I have a 4X10 supply line to feed the room with a little fresh air, but we hardly use the HVAC.
IMHO, that's a good plan for your situation, based on what you've described so far.

6" sounds like a rather wide light tray, FWIW. You could also consider placing it externally to the soffit. Here's an example. Food-for-thought.

Regarding the HVAC vent: just a suggestion you take into account your total cubic volume of the room, how you will control heat/cooling into the room, and how your equipment and max # people in the room at one time may impact your comfort. Other factors to consider include noise. I'm just suggest you don't overlook HVAC from several perspectives. And since you are building a soffit anyway, one option would be to re-locate the single existing vent to vents in either side soffit as a means to control air flow, noise, etc.

Another factor related to HVAC is the fact that doing a good job of sound-proofing your room also entails making it air-tight. Thus, your HT room's air will become stale pretty quickly while watching a long movie or other activities. This is also why you should place a return vent in your HT room. Think of your HT room as a mini-climate ecosystem.


Quote:
I'm wondering if it would be safest to drape velvet directly over the styrofoam of the ICF to keep the hard surfaces at bay. I do need to darken it up back there. I will have about 8" of the angled turret remaining in front of the screen once the screen wall and speaker shelving is built. I could build a baffle wall on each side to eliminate the angles, but I'm thinking that could cause odd deflection as well. Maybe it's just one of those things I should leave well enough alone.
It's not a bad idea to drape something over the ICF, however I'd suggest MLV (Mass Loaded Vinyl). You'd need to figure out a suitable way of affixing it to the ICF (e.g. concrete screws with big washers). That would be much more useful than velvet as it would attenuate all the frequencies before and after they bounce off the ICF.

Having that wall extend to the sides of your stage may exacerbate the concern I raised about sound deflection off that wall. However, it's also an opportunity to turn it into a style choice relative to your stage. For instance, you could create triangle shapes on the sides of your stage and place your side speakers outside the screen real estate, such as this theater design. Just an idea.


Quote:
I think I'm sold on the double dry wall with clips and channel. I do need to get educated more on how to properly do the clips and channel, so I will research that some. I'm sure a search in this thread will yield something educational for me, but if you know of a specific thread or search that I should do, I would appreciate it. I will plan to do this on all of the wood framed walls. I'm scratching the OSB idea, so my final dilemma is 1/2" vs. 5/8".
There's lots of info on AVS, as I'm sure you know. This thread will help get you started tho.


Quote:
We have a very open design on our house, so I'm thinking I better do the sound control right the first time around. I'm at the stage where it is easy to do, so I don't want to be kicking myself later on down the road.
Yes. Agreed.


Quote:
Thanks again for all of your assistance! Obviously you've got an open invite to check out the theater when it's completed. Decent excuse for a trip to Alaska, don't ya think?
Thanks! I may take you up on that offer in July when it is 110 here in Austin. LoL.
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post #1678 of 2427 Old 11-04-2016, 02:28 PM
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This is perhaps a bit better example of upward soffit lighting (versus my previous post).
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post #1679 of 2427 Old 11-04-2016, 06:05 PM
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Originally Posted by HT Geek View Post
I understand your conundrum, but it's a bit of a loaded question as you put it above. By that I mean - for example - if your room's ceiling is attached to the structural ceiling joists, then what you are proposing will have a minimal benefit because sound will travel via the ceiling joists to which your drywall is directly attached.

Now, if let's say you have some sort of isolation (such as clips & channel) between your ceiling joists and your drywall ceiling, then at that point doing what you propose begins to become more effective as you are blocking some of the sound traversing through the open cavities in the ceiling between the joists.

All that said, if you still want to consider implementing your plan, a diagram would be helpful for other folks to ascertain the potential effectiveness. Photographs would be even better. Some folks on AVS will tell you it's an all-or-nothing proposition, but I personally believe the devil is in the details. There are some cases where not having 100% of the joists dampened might not be a big deal. So, if you have photos or a diagram, please share so that we can do a more thorough job of advising.

I will post some pictures soon.

Sorry I did forget to mention I will using a channel for the ceiling and will also add some roxul sound insulation in between the joists.

I know I won't have complete soundproof. Just want to do the most I can with what I already have.
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post #1680 of 2427 Old 11-04-2016, 06:08 PM
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Yes, it's all just a matter of degrees and wether or not a solution meets your requirements. If you are expecting X results but your solution just provides Y, then you'll be disappointed. But if you only expected Y from the start, then anything more is overkill.

Let's start with the fact that doing anything is going to be measurably better than doing nothing. Filling 20 of 24 joist bays will absolutely make a difference as that will attenuate a significant amount of sound energy. Some will absolutely flank around the treated bays into untreated ones but very possibly not enough to bother you.

Likewise with using drywall without GG. The additional mass is the bulk of the benefit anyway and the GG just adds an extra "kick" with its damping. I've always put GG in the "very nice to have if you can afford it" category vs the "must install" like extra mass.

Let's take a step back, though... why are you wanting to treat the inside of the joist bays? Is this just an extra step in addition to the primary treatment of the ceiling itself? If it's a standalone treatment then... well, it will certainly do something but it does get less likely that it'll do enough to satisfy what you have in mind. Handling the joists bays is traditionally the last little bit done to eek out the final bits of performance out of a comprehensive solution and almost never done standalone.
Sorry I forgot to mention I will be using channels on the ceiling and most likely DD. I will definitely be adding roxul between the joists.
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