AVS Forum banner

3181 - 3200 of 3549 Posts

·
Registered
Joined
·
773 Posts
Yes, it will help more with higher freqs vs. LFE.


Horse stall mats and rubber mats in general are helpful, and they will mitigate some of the sound. However, loud and deep bass is going to pass through easily. It's really tough to say ahead of time if you'll be satisfied with the result. I can tell you IMHO, with a 2nd floor theater room, the floor in the HT room is the biggest challenge. Your best bet with that floor would be to rip out the sub-floor and de-couple the room's floor. I know that is a huge pain and easier said than done.

Presuming you don't do that, even with a floating floor, you're going to get considerable pass-thru sound (LFE in particular). Lay down a double-layer osb/rubber/osb/rubber combination (or similar) if you have the means. Anything you do above and beyond a normal floor will help. Thick carpet pad would be helpful as well. Just don't expect a miracle. :)

You'd have to contact Kinetics and ask them if they have a reseller local to you, or if they would sell direct. It's not cheap, but thought I'd throw that out as an option.




I concur.

Why would ripping out the existing subfloor and decoupling a new subfloor from the joists necessarily be better than leaving the existing subfloor and decoupling it from a secondary subfloor laid over it?


My impression is that the primary reason not to put down a secondary decoupled subfloor is that I've got some untreated walls that will create a flanking issue, especially for lower frequency sound.


And if I had to guess, putting down rubber-second subfloor-rubber-third subfloor would yield only marginal improvements over the more basic rubber-second subfloor. If anything, if I were looking for a more involved floor treatment, I'd think rubber-second subfloor-Green Glue-additional subfloor sandwich would be a better bet, creating a single more massive suspended subfloor and damping it to boot. Anyway, this is all hypothetical, because if the case for a simpler floor treatment is tenuous, it's all the more so for a more involved treatment.
 

·
Registered
Joined
·
1,599 Posts
Why would ripping out the existing subfloor and decoupling a new subfloor from the joists necessarily be better than leaving the existing subfloor and decoupling it from a secondary subfloor laid over it?

My impression is that the primary reason not to put down a secondary decoupled subfloor is that I've got some untreated walls that will create a flanking issue, especially for lower frequency sound.

And if I had to guess, putting down rubber-second subfloor-rubber-third subfloor would yield only marginal improvements over the more basic rubber-second subfloor. If anything, if I were looking for a more involved floor treatment, I'd think rubber-second subfloor-Green Glue-additional subfloor sandwich would be a better bet, creating a single more massive suspended subfloor and damping it to boot. Anyway, this is all hypothetical, because if the case for a simpler floor treatment is tenuous, it's all the more so for a more involved treatment.
It's a matter of degree. As in... to what degree you think you want to mitigate sound leaving or entering the HT room, and to what degree you are willing to invest the money and/or time in attaining the goal? And of course, what are the ramifications if you miss your goal?

Your floor is the biggest surface that is going to resonate most directly toward the area in which you (I believe) would prefer to mitigate sound traveling (i.e. to the room below).

Yes, you're still going to have side-flanking issues. I was thinking of ideals (re: floor). If you are directly below the room, you will hear it better than almost anywhere else in the house.

Are you thinking it's not worth it to invest a lot of effort into the floor because you've already decided not to go all out with the walls and ceiling? I'd say it's a reasonable argument to ask whether it's worth bothering with just one surface if you're not truly addressing the other surfaces. But, again it's a factor of degree. You *might* get some benefits through partial treatments here and there, but then again it might be a waste of time and resources. There's really no way to know unless you're going to try and conduct a true A/B test (almost impossible outside a lab).

Perhaps we are splitting hairs here, but I was just trying to point out that unless you are willing to go to extremes, the benefits (re: floor) are going to be very limited no matter what you do.
 

·
Registered
Joined
·
1,599 Posts
Good to know, why I never like to rely on 1 single source of truth, also trying to find things that apply to Canadian code as well vs U.S Code.

For the insulation,based on my picture, would i be better off to cut down the middle of that insulation and have it more "wrap" over/under the duct work vs having it slightly compressed above it? The insulation is 6" thick it notes, but above the duct it may be compressed down a bit to more like 5".
Cut it and wrap it. You should avoid compressing it.

I'll try and give you a brief primer on the relevant theory. Insulation - when loosely packed - reduces the velocity of sound waves traveling through it (good for HT rooms). However, if you squish that insulation together and compress it, then it functions more like a solid, which tends to be better at resonating (conducting) sound (bad for HT rooms).

Likewise, loose insulation around your HVAC ducts will help to muffle any normal operating noise emanating from them, and help keep sound in your room from vibrating the ducts.
 

·
Registered
Joined
·
42 Posts
Cut it and wrap it. You should avoid compressing it.

I'll try and give you a brief primer on the relevant theory. Insulation - when loosely packed - reduces the velocity of sound waves traveling through it (good for HT rooms). However, if you squish that insulation together and compress it, then it functions more like a solid, which tends to be better at resonating (conducting) sound (bad for HT rooms).

Likewise, loose insulation around your HVAC ducts will help to muffle any normal operating noise emanating from them, and help keep sound in your room from vibrating the ducts.
Perfecto! Shall cut and wrap where needed!
 

·
Registered
Joined
·
607 Posts
Soundproofing an Existing Finished Basement

Thanks to some sloppy craftsmanship and general shortcut-taking, I'm looking at needing to tear down my HVAC soffit and the surrounding ceiling to replace some HVAC ducts.

As long as I'm going to be tearing "some" down, I'm considering whether I should tear the whole thing down and do some soundproofing.

Room is 7'2" high, so I'm not sure I can even consider decoupling and using double sheetrock / green glue. At a bare minimum, I know I can at least use Roxsul to fill the cavities, despite knowing this isn't a very good solution at all.

There's current zero insulation between floors. But there's also plumbing and electrical to consider. My primary consideration is limiting sound from the basement leaking upstairs. I'm not too concerned about impact noise from the floor above.

Wondering if this fine forum might have some tips on how to think about the issue and get the wife on-board.
 

Attachments

·
Registered
Joined
·
58 Posts
Simple question (I hope).

If you double layer plasterboard or, as I’m planning, OSB then Plasterboard, how do you fix the second layer?

Presumably the uprights at 16’’ centres and associated noggins are correctly placed for the first layer. If you stagger the layers then the second layer will miss the studs.

If I use OSB, can I fix the plasterboard layer to the OSB or does it need to fit a stud?

No channel etc involved as it’s an isolated stud frame.
 

·
Registered
Joined
·
85 Posts
Simple question (I hope).

If you double layer plasterboard or, as I’m planning, OSB then Plasterboard, how do you fix the second layer?

Presumably the uprights at 16’’ centres and associated noggins are correctly placed for the first layer. If you stagger the layers then the second layer will miss the studs.

If I use OSB, can I fix the plasterboard layer to the OSB or does it need to fit a stud?

No channel etc involved as it’s an isolated stud frame.
Hi,
With 2layers of drywall, both layer have to hit the channel or 2x4 or 2x10 behind the 1rst layer. You have to carefully mark them. The cnrc have a example of the screw pattern they used for their testing of the wall isolation. Look it up.

With osb as the first layer, I think you still should screw the 2nd layer directly into the joist to avoid any sagging. It's even more important if you are using hats and channel because the connection of screws and channel are not that strong. On the walls you could screw the 2nd layer with no respect to where your studs are behind because the lateral force are very little.

Now the fun thing with 1layer osb is that you can add anything and screw anywhere and it will hold.

It takes a little bit more time to do properly, but I the end, I think it's worth not having to fix it.

-Matt
 

·
Registered
Joined
·
1,599 Posts
If you double layer plasterboard or, as I’m planning, OSB then Plasterboard, how do you fix the second layer?
You still need to screw it into the studs. Alternate your screw offset. Ceilings normally have more screws, but depends on the installer.

Either way, as an example, offset 6" from ceiling and put a screw every 12" or so. Then on your 2nd layer, start at a 2 or 3 inch offset and alternate 12". Using that technique, you can use fewer screws in the 1st sheet if you like since the 2nd layer screws go through the first. 1" + drywall thickness for 1st layer and (+ drywall thickness for 2nd layer). Figure 1-5/8" and 2-1/2" screws respectively, or perhaps something close in wood screws for first layer. Drywall screws usually work well enough tho under the circumstances (1st layer). Make sure you dimple the 2nd layer screws. There are special drill bits you can find that make it easier.

If you stagger the layers then the second layer will miss the studs.
You just need to line everything up where you can. If you use enough screws where there are studs, it won't be an issue. Use some extra screws if you have fewer joists to attach to.

If I use OSB, can I fix the plasterboard layer to the OSB or does it need to fit a stud?
Yes, it still should be attached directly to a stud. BTW, using OSB for the 1st layer is more challenging than it might seem beforehand. It's more difficult to cut and line up compared with drywall, and it's more challenging to create smooth seams. I would recommend staggering the drywall over top of it.

Also, it does not help you from a sound proofing standpoint. There is a benefit to hanging things, as you mentioned.
 

·
Registered
Joined
·
1,599 Posts
Thanks to some sloppy craftsmanship and general shortcut-taking, I'm looking at needing to tear down my HVAC soffit and the surrounding ceiling to replace some HVAC ducts.

As long as I'm going to be tearing "some" down, I'm considering whether I should tear the whole thing down and do some soundproofing.

Room is 7'2" high, so I'm not sure I can even consider decoupling and using double sheetrock / green glue. At a bare minimum, I know I can at least use Roxsul to fill the cavities, despite knowing this isn't a very good solution at all.

There's current zero insulation between floors. But there's also plumbing and electrical to consider. My primary consideration is limiting sound from the basement leaking upstairs. I'm not too concerned about impact noise from the floor above.

Wondering if this fine forum might have some tips on how to think about the issue and get the wife on-board.
There's a lot of, "Well, it depends..." thoughts going through my head based on your comments. If you're looking for general advice, I would suggest you stuff some "pink fluffy" insulation in there after you complete repairs rather than Roxul. It's cheaper and more malleable in that type of situation.

If it's unclear what you are going to do with this space in the future, I'd stop there for now.
 

·
Registered
Joined
·
607 Posts
As long as I'm going to be tearing "some" down, I'm considering whether I should tear the whole thing down and do some soundproofing.

Wondering if this fine forum might have some tips on how to think about the issue and get the wife on-board.
There's a lot of, "Well, it depends..." thoughts going through my head based on your comments. If you're looking for general advice, I would suggest you stuff some "pink fluffy" insulation in there after you complete repairs rather than Roxul. It's cheaper and more malleable in that type of situation.

If it's unclear what you are going to do with this space in the future, I'd stop there for now.
So that's pretty much where I'm at, and my major concern is just having to do demo and reno twice.
 

·
Registered
Joined
·
1,599 Posts
So that's pretty much where I'm at, and my major concern is just having to do demo and reno twice.
So, do you have plans for this room to be converted to a home theater room?

Based on the constraints you described previously, I'd suggest considering a drywall/Green Glue/drywall sandwich. It can be done within 2". That would limit your height loss and keep you within 7', which will satisfy building codes in most of the country.

OR

Another option is to wait. There are some short height clips out there. You could do clips + hat channel + 1 sheet of 5/8" = 2"

 

Attachments

·
Registered
Joined
·
58 Posts
You still need to screw it into the studs. Alternate your screw offset. Ceilings normally have more screws, but depends on the installer.

Either way, as an example, offset 6" from ceiling and put a screw every 12" or so. Then on your 2nd layer, start at a 2 or 3 inch offset and alternate 12". Using that technique, you can use fewer screws in the 1st sheet if you like since the 2nd layer screws go through the first. 1" + drywall thickness for 1st layer and (+ drywall thickness for 2nd layer). Figure 1-5/8" and 2-1/2" screws respectively, or perhaps something close in wood screws for first layer. Drywall screws usually work well enough tho under the circumstances (1st layer). Make sure you dimple the 2nd layer screws. There are special drill bits you can find that make it easier.



You just need to line everything up where you can. If you use enough screws where there are studs, it won't be an issue. Use some extra screws if you have fewer joists to attach to.

Yes, it still should be attached directly to a stud. BTW, using OSB for the 1st layer is more challenging than it might seem beforehand. It's more difficult to cut and line up compared with drywall, and it's more challenging to create smooth seams. I would recommend staggering the drywall over top of it.

Also, it does not help you from a sound proofing standpoint. There is a benefit to hanging things, as you mentioned.
Appreciate all the input. That’s much clearer thank you.

I know osb makes no difference for sound proofing but figure it’ll make fixing soffit and wall mounted surround speakers a lot easier. Appreciate dry wall cuts easy but hopefully not too bad with decent circular saw etc.

If I stagger all the seams and top layer is drywall hoping seams shouldn’t present an issue?
 

·
Registered
Joined
·
1,599 Posts
Appreciate all the input. That’s much clearer thank you.

I know osb makes no difference for sound proofing but figure it’ll make fixing soffit and wall mounted surround speakers a lot easier. Appreciate dry wall cuts easy but hopefully not too bad with decent circular saw etc.

If I stagger all the seams and top layer is drywall hoping seams shouldn’t present an issue?
Yes, it can be a plus for certain things. Really depends on the details, but it may be helpful. Regarding cutting and fitting it, what you'll likely find is it's the detailed trimming that becomes a pain, such as in a corner. With drywall, you can cut and snap in place much of the time. Even if you can't do that, it's quicker and easier as you don't need a saw, etc. Another factor is you can patch the drywall if you nick a bit here and there, if necessary. YMMV. I have been there, done that and I would probably not do it again. It was just more work. I do agree that especially on the walls it can be a plus, but only if you know you will be hanging things and want/need the extra support vs. 2x drywall layers.

The OSB seams don't line up quite as nicely as drywall, but since you will have the drywall over top if it, should be non-issue regarding the finished product. With respect to the OSB seams, they're not smooth like drywall and they aren't as easy to seal as drywall seams (e.g. sound proofing caulk).

Just plan to spend more time installing the OSB than you would for a drywall layer and you should be OK.
 

·
Registered
Joined
·
607 Posts
So, do you have plans for this room to be converted to a home theater room?

Based on the constraints you described previously, I'd suggest considering a drywall/Green Glue/drywall sandwich. It can be done within 2". That would limit your height loss and keep you within 7', which will satisfy building codes in most of the country.

OR

Another option is to wait. There are some short height clips out there. You could do clips + hat channel + 1 sheet of 5/8" = 2"

Very helpful. Guess the next question is if one is a much better option than the other? I've been doing as much reading as I can on the subject, and wondering if clips might be better for "impact noise" but the double layer w/ Green Glue might be better for "airborne noise"?

I'm not turning the room into a dedicated theater, but it is a media room / kids play room that I'd love to be as quiet as possible (within reason). I'd like to be able to watch a movie or listen to music at night without the sound travelling to the 3rd floor. Not too concerned with foot traffic.

With the limited wiggle room I have on the ceiling height, I could consider something like a low-profile clip, which might give me the space I need for a double layer. https://www.acousticalsurfaces.com/rsic_clips/rsic-1-low-profile.html

I realize there are a few ways to approach the issue, and you're 110% right. "It depends" is all over the place. It depends on how much of the ceiling really needs to come down to fix the HVAC. If its ultimately "not that much," then tearing the whole ceiling (and possibly walls) down seems like a bad investment of time and money.

Thanks @HT Geek. I really appreciate your input and thoughtful consideration.
 
  • Like
Reactions: HT Geek

·
Registered
Joined
·
813 Posts
Hi all

Airgap importance?

Trying to decide on:

Solid wall (light concrete) + airgap(rockwool) + clips/channels + dual plasterboard + GG

Difference airgap 2" vs 4"?

And how about a 3rd layer of plasterboard?

Basicly I am trying to make the slimmest possible soundproofing "cost no object", and I cannot find any way to calculate the benifit of a larger airgap?

Any other solution I should look at other than what I often see used here which is 2 by 4's + clips/channels and plaster/GG?

/Regards
 

·
Registered
Joined
·
85 Posts

·
Registered
Joined
·
1,599 Posts
Well... If you want to see a different approach, there's is this guy that is using mud and stray bale.

https://r.tapatalk.com/shareLink?url=https://www.avsforum.com/forum/showthread.php?t=2997154&share_tid=2997154&share_fid=47413&share_type=t
Soon to be known on this forum as "brown scratchy," cousin of "pink fluffy" and coming soon to AVS... "The Hay-Fever Theater Build."

Building inspectors around here would just love the Romex sandwiched in between straw whilst we're in the midst of burn ban and the air is 100+ and about 25% humidity.

LMAO when she gets out the chainsaw. I might have to try that the next time I need to cut some drywall... not.

https://youtu.be/A7u76MyqR6s?t=300

I also don't understand why she mentions CO as an issue. I think that would be the last of my concerns. At least unless it's a by-product of the house being on fire. Hmm.....

Hopefully, no one in the house is a smoker... better have a good electrician too... would hate to have a short or loose wire... sheesh.... Drywall is a bad enough "fire resistant" material (B.S.)... I'll stick with my 30-90 seconds to GTFO out of a burning house, thank you. Better than zero.
 

·
Registered
Joined
·
1,599 Posts
Hi all

Airgap importance?

Trying to decide on:

Solid wall (light concrete) + airgap(rockwool) + clips/channels + dual plasterboard + GG

Difference airgap 2" vs 4"?

And how about a 3rd layer of plasterboard?

Basicly I am trying to make the slimmest possible soundproofing "cost no object", and I cannot find any way to calculate the benifit of a larger airgap?

Any other solution I should look at other than what I often see used here which is 2 by 4's + clips/channels and plaster/GG?
To answer your core question, there is no benefit to a 4" air gap vs. 2". I would not consider anything less than 1/2" absolute minimum. You need a bit of space to allow for variations in materials. A 1" gap is a good general guideline for most builds.
 

·
Registered
Joined
·
1,599 Posts
Very helpful. Guess the next question is if one is a much better option than the other? I've been doing as much reading as I can on the subject, and wondering if clips might be better for "impact noise" but the double layer w/ Green Glue might be better for "airborne noise"?
Do you mean clips with 1 layer of drywall vs. 2x drywall/GG sandwich directly attached to studs and no clips?

Without digging up lab tests to get a definitive answer... I would say your best bet for both problems is likely to be doing both: i.e., 2x drywall/GG sandwich attached to clips. They can hold the weight with no issues when the clips are spaced properly.
 
3181 - 3200 of 3549 Posts
Top