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Soundproofing master thread - Page 6

post #151 of 351
Thread Starter 
Quote:
Originally Posted by BasementBob View Post

BuildWall2_gap_mudtape.gif

BuildWall2_zigzag4.gif

Right! I meant to talk about these at the time, but got distracted.

Let's contrast the Zig Zag description with the Soundproofing Company's Soundproofing Tip: Ceiling to Wall Seam Intersection. They also recommend a zig-zag pattern BUT, crucially, they differ by saying "Note that we want solid drywall to drywall contact. Don’t try and leave a gap." That makes sense to me... why would leaving a gap be preferable in this case?

Both recommendations say to use acoustical caulk. I'm not seeing the advantage of using that over normal drywall mud in any drywall-to-drywall seams, though. Both have roughly the same density and both should seal any air gaps for the long term.

Also, what is the thinking behind using mud only if a drywall seam has recessed edges but caulk, otherwise. Simply aesthetics (no bulge) or is there another reason?
post #152 of 351
I disagree with BB's diagram of drywall on the wall, You end up with butt joints which are harder to tape and make disappear. You can reverse the sequence or just do all the panels vertically and stagger the seams.
post #153 of 351
Granroth:
re post #151

Think about what is required to get acoustical sealant into the vertical gap in:



If it's a big ceiling you might get away with coating one or two edges of the drywall with acoustical sealant, but odds are you'll have gaps that it gets scraped off for one reason or another, and once its up there's nothing you can do about it. But the problem isn't with the first piece where you have oodles of room -- its the last piece of ceiling drywall where your tolerance is so small you're guaranteed to scrape off the goop (acoustical sealant) as you put it in place.
In a closet or narrow up/down soffit spot such as near an overhead pipe/duct or I-beam/joist, you might have to coat three edges or even four. There's no way to lift drywall with four edges covered in goop without scraping it off on the walls on the way up.
Similarly, you might be able to do the ceiling, but you can't also do the floor -- one side or the other, you'll be scraping the goop off by putting the close fit drywall in place.
That said, sealant is kind of sticky, and you might get away with running the goop in the corner before putting the drywall into it, and hoping it'll squeeze into the gap rather than uselessly as most of it ends up behind the large flat side of the drywall sheet -- not remotely optimal, but better than having it scrape off on the walls.

There's also some drying possible with acoustical sealant -- but if you have lots of it, it will stretch nicely. A quarter inch, is about optimal.
Note that too much gap doesn't work at all, within a few months the sealant will fall off one edge or another -- that's why the backer rod has to be in there so the sealant is 1/4" deep as well as tall -- acoustical sealant lasts really well in 1/4 inch gaps. (the backer rod provides no soundproofing of itself, its just there to keep the acoustical sealant optimal)


The acoustical sealant is for where cracks in mud/tape tend to appear -- look at your own house, I'll bet you'll see more cracks in corners than on long walls. There's more movement in corners than in long walls.


So my (Rod's) drawings are acoustically and 'structurally' sound -- 'structurally' used here to mean it'll last.
They're also much easier for tired stupid helpers to put up without creating failure.

FYI, my two drawings were based on some writings of Rod Gervais, and were subsequently modified a few times until Rod Gervais approved them. The second one for example is named 'zigzag4.gif'. That's because he rejected 'ziggaz1.gif', 'ziggaz2.gif', 'ziggaz3.gif' which matched his post, but not what he understood.

If someone can get Brian to look at this and say Rod is wrong, I'll accept it. But no one else from the soundproofing company trumps Rod in my opinion.
Edited by BasementBob - 2/22/14 at 10:16am
post #154 of 351
Hoping someone can settle a debate I'm having. I have already framed wall 1" from basement foundation. My good friend does spray foam insulation. My thought is to move wall 2" off foundation, spray 1" with foam, 1" gap, pink fluffy for stud cavity and isolate wall from floor joists above with clips. He thinks should leave studs as is, spray foam to fill gap and 1/2" into stud cavity and then use fluffy for rest of stud cavity and clips for joists above. He thinks foam will stop sound by stopping studs from vibrating. Either way we'd also use DD+GG. Any thoughts?
post #155 of 351
don't listen to your friend, he may know foam, but he doesn't understand mechanical isolation in the context of soundproofing. Stopping rattles can often mean transferring the vibration to something else.
post #156 of 351
Thread Starter 
Quote:
Originally Posted by Gnaw em Gophs View Post

Hoping someone can settle a debate I'm having. I have already framed wall 1" from basement foundation. My good friend does spray foam insulation. My thought is to move wall 2" off foundation, spray 1" with foam, 1" gap, pink fluffy for stud cavity and isolate wall from floor joists above with clips. He thinks should leave studs as is, spray foam to fill gap and 1/2" into stud cavity and then use fluffy for rest of stud cavity and clips for joists above. He thinks foam will stop sound by stopping studs from vibrating. Either way we'd also use DD+GG. Any thoughts?

Nope. Honestly, this isn't even really a debate in the classic sense -- your friend is just completely wrong. So wrong, in fact, that I'm genuinely curious where he even got the impression that sound vibrations work that way. Ask! I want to know. biggrin.gif

The method you describe is pretty much the standard way to do this, so stay the course.
post #157 of 351
All foam is rigid. It can be used to couple two leaves together if there's a triple leaf problem.

There's open cell foam and closed cell foam. Open cell has some sound absorptive abilities like fluffy fiberglass pink. Closed cell is a better insulator and a vapor barrier. Basements, and most foam installers, usually use closed cell foam to give a thermal break and vapor barrier.

Using both foam and fluffy may move the condensation point out between the two, and create mold there. Here in chilly Canada the rule is vapor barrier on the room side of the insulation, which is usually at the drywall -- but closed cell foam without fluffy is its own vapor barrier which is fine by itself. Mold is worse than noise pollution. Two vapor barriers (one closed cell foam on the concrete, and another 6mil poly at the drywall), is worse again. If you use both foam and fluffy fiberglass, ensure that whatever you make the wall out of is moisture and mold proof, and that any moisture has some place to go.

If the top plate of your stud wall is attached (touching and nailed) to the bottom of the joists, then your decoupling isn't complete anyway and you'll get so much flanking through that path that foam connecting the concrete wall to the studs probably isn't going to make much difference.
If you're using wall sway braces with neoprene isolator pads on your top plate (and thus the top plate not touching joists or wall), then coupling the studs to the concrete wall with foam would be a mistake.
If your stud top plate is free (not attached to anything, and no sway braces) you may be violating building code -- which is a nice way of saying your walls may move enough that the ceiling may separate or fall.
If you use clips both on the ceiling and the studs, then it doesn't matter if your studs are coupled to the concrete wall with foam or coupled to the joists.

If you use clips on the ceiling, but not on the studs, then you want the studs decoupled as much as possible -- which means no foam attaching to both the concrete wall and studs.

If your foam guy can do one inch of foam on the concrete and not touch the studs, he's a real artist at it. More likely he'll accidentally hit the studs in some bits, and you'll take a drywall saw and separate the foam off the studs.

If I were building a basement for living, I'd use closed spray foam without fluffy -- lots of closed spray foam.
If I were building a basement for theatre, I'd skip the spray foam completely, just use 3"+ fluffy and vapor barrier.

If you must use both foam and fluffy, use as little fluffy as possible. You don't need much fluffy to get the most soundproofing benefit, and the less thermal insulation the fluffy provides the more likely the condensation point will be inside the closed cell foam somewhere which is just fine. For example, 3" of closed cell foam, 1" air gap, 1" fluffy in the studs, would be fine just about anywhere.
Edited by BasementBob - 2/23/14 at 1:25am
post #158 of 351
I am going to have to read far more in this particular thread as it is proving very educational for my next project.

In the meanwhile, I have a situation that perhaps some folks here would be able to give me some options, guidance or sites to read up on to help with a particularly troubling scenario -

I live in a rented flat that has AC units on the roof. They not only make "air noise" I can hear in my flat but also mechanical noise which for me is far worse. Since I cannot really open up the walls, is there any treatments that can be done to the interior walls and ceiling that are also cost effective? The noise and vibration often kills some of my music and movie experience and afterwards culminates into going to bed with the sound of a "dishwasher" above my head and down the walls and then some (including the flat below me having its air circulator making my floor slightly vibrate along with noise it creates0.
post #159 of 351
they do make rubber isolation pads for mechanical equipment which might help a little bit, it is hard to know without looking at the AC units. As far as treating your flat, it would probably be cheaper to move. That is the beauty of renting. In the mean time get a good pair of surround headphones.
Edited by BIGmouthinDC - 2/23/14 at 9:38am
post #160 of 351
Thanks BIG, granroth and BB. Helpful.
post #161 of 351
Quote:
Originally Posted by BIGmouthinDC View Post

they do make rubber isolation pads for mechanical equipment which might help a little bit, it is hard to know without looking at the AC units. As far as treating your flat, it would probably be cheaper to move. That is the beauty of renting. In the mean time get a good pair of surround headphones.

I suppose you are correct about moving (a serious consideration). I admit being frustrated to be recipient of these noises without any recourse and was hoping there was a possible way to add some dampening or absorbing material that didn't cost a fortune. Thanks for the "move out" suggestion as it is honest and logical.
post #162 of 351
Phrehdd, your description of the problem leads me to believe you could spend several thousand dollars on materials and labor to tame the noise you hear and still not have a guarantee that you will be happy with the result.
post #163 of 351
Quote:
Originally Posted by BIGmouthinDC View Post

Phrehdd, your description of the problem leads me to believe you could spend several thousand dollars on materials and labor to tame the noise you hear and still not have a guarantee that you will be happy with the result.

I am sure you are correct. - A rather frustrating matter for anyone to pay rent and continue with the level of noise. Sadly, I am sure there is little legal recourse (as opposed to doing internal fixes myself). Again, thanks for the honest and straight forward response. I'll just say when the place is quiet I get a great deal of joy out of my equipment whether watching movies or playing 2 channel and multi-channel music. In the meanwhile, I'll read through all these posts to get some ideas for what I guess will most likely in the near future be my new residence.
post #164 of 351

Changing the direction of conversation for a brief moment please?

 

Unlike the current discussion problem I have a below ground and separate from my house (below the patio) basement area made of concrete blocks without any chance of sound interference from anywhere - I even have a solid fireproof door!

 

My question is given that the whole room is made out of concrete blocks and my projector will be in a separate projection media 'room', what sort of Soundproofing should I be considering. I realise that most of the discussions in this thread relate to 'wood or stick built' houses and apologise in advance if I am out of order. I am located in Cornwall, England where everything is made from Granite! Also I am going to put in a sub floor to run the cables and electrics through and I will be raising the back area so I can get in two rows of seats?

 

I intend to plaster the screen wall and paint it with an appropriate paint once I have chosen a projector. I do have to insert a ceiling so any advice or guidance will be much appreciated. I am intending to post the whole design and build process in the Forum but as I am at the pre-design stage I thought I would get all my ducks in a row before being given a lecture in my mistakes before I start by the likes of BigMouthinDC (Jeff Parkinson)

 

In anticipation - Many thanks

post #165 of 351
sounds interesting, I suspect your biggest problem will be sound quality rather than sound proofing. I imagine that currently the room is very reverberant with all the hard parallel surfaces.
post #166 of 351

The actual Room dimensions of the Theatre seating is 20 ft by 12 ft with a finished ceiling height of 7ft 4 inches (6.11 x , 3.76 x 2.25 metres) I have attached a  preliminary layout which might help explain.. Any thoughts will be much appreciated. 

As for the sound... I have decided to go down the 2:1 Audio route using some very impressive Event Opals which are Active Studio Monitors being driven either by an Oppo 105D or via my HTPC.

 

 

 

 

post #167 of 351
My question is what is above the room and how is that constructed. Poured concert slab making it truly a bunker or is it conventional floor joists? If standard joists with a room above you will have the flanking issues to the rooms upstairs. It that space is your attic you will still have the flanking to the rooms beside and behind the theater. That would need to be addressed.
post #168 of 351

Hi there cw5billwade - The construction of the ceiling / roof is of Pre stressed Concrete T Beams in-filled with concrete Blocks with a poured layer on top of waterproof concrete. I have attached a few Photos below to help one understand the problem..

 

The top picture is  a close up of the T Beam infilled with the concrete block.

The second is a view of the room scheduled for converting into a Home Theatre as per the earler post. The photo below shows a view of the conservatory which sits above and on the concrete T beam floor. The Theatre is below the Patio which is highlighted.

post #169 of 351
We bought a higher end house that was built in 2008. We bought the house a year ago and renovated the main and upper floors. Its now time to start planning and building the media room area

One thing we've learned living in the house is that sound from the basement is easily heard on the main floor. There is no way that we could use a media room in the basement the way it is without it being noisy on the main floor. Basically we need a way to soundproof the ceiling in the basement.

The basement is fully framed, dry walled and painted. The media room area is nothing more than walls, ceiling and floor at this point. Its just a big room with no screen, lighting, carpet, etc. We intend to make some significant changes in the room.

The basement has 9 foot ceilings with 1/2" lightweight drywall on them. The main floor has good quality 3/4" plywood underlay covered with brazilian cherry hardwood. There is no rug anywhere on the main floor. The floor joists are about 16" tall. There is no insulation between them.

So... is there an easy way to soundproof the basement ceilings without ripping them out and starting over ?

Is it better to tear out the existing ceiling and insulate between the joists and then put up an isolated ceiling or leave the existing ceiling in place and put up a sub ceiling and insulate between the two ceilings ?

Thanks
post #170 of 351
marvoroberts:

Years ago I got some theatre projection room glass (optically perfect glass for projecting an image through).
I don't remember where I got it from. It was 6"x6" (15cm x 15cm).
With your projector in a different room, you'll probably want something similar to put into the wall behind your seating -- for soundproofing reasons to reduce the noise of the projector or anything else you might have in the media room (such as a PS3-bluray with a noisy fan).
Edited by BasementBob - 2/24/14 at 12:30pm
post #171 of 351
marvoroberts:

I'd start with the concept of a noise floor [e.g. 25db(A) to 35db(A), or NC rating]. If the room is quiet enough, you won't be turning the volume up to hear the quiet bits which would otherwise be masked by noise (signal-to-noise ratio of 70dB is fair, 80dB is preferred, 95dB is more expensive). Where the noise floor is, is a design decision to be made (NC 100 noise floor is really cheap [paper bag], NC 5 noise floor is extremely expensive [demolish your house and start over]). If you're practically deaf, and play everything loud all the time, you can also have a higher noise floor.
The THX ratings are something like: "The steady-state theatre noise floor should preferably be below NC25, with NC30 the worst case acceptable. Intermittent increased noise floors should not exceed NC35."

How quiet is the room now? Can you hear aircraft, bus/truck traffic, hvac/plumbing/dishwasher? Put a boom box (portable CD player) on a chair on the patio, and measure the sound loss. Put a subwoofer in the basement, and measure the sound in the room to determine the transmission loss through the fire door. If the sound transmission loss is already high enough to knock the central heating blower's basement noise under your noise floor, then that's great.

If you put a subwoofer into the room and play it loud [90db @20-70hz], can you hear it in your house, particularly the bedrooms? Do the kitchen dishes rattle? Do the neighbours hear it?

If you can't hear outside noise, and the outside can't hear you, then you're already done soundproofing, except for hvac (which is both a noise transmission conduit, and a source of wind/blower noise).

In otherwords, measure what you have now, then engineer what you're going to do to fix it. If the diagnosis is that you're already fine, then do naught.
Edited by BasementBob - 2/24/14 at 12:52pm
post #172 of 351
Quote:
Originally Posted by marvoroberts View Post

Hi there cw5billwade - The construction of the ceiling / roof is of Pre stressed Concrete T Beams in-filled with concrete Blocks with a poured layer on top of waterproof concrete. I have attached a few Photos below to help one understand the problem..

The top picture is  a close up of the T Beam infilled with the concrete block.
The second is a view of the room scheduled for converting into a Home Theatre as per the earler post. The photo below shows a view of the conservatory which sits above and on the concrete T beam floor. The Theatre is below the Patio which is highlighted.

Quote:
Originally Posted by BasementBob View Post

marvoroberts:

I'd start with the concept of a noise floor [e.g. 25db(A) to 35db(A), or NC rating]. If the room is quiet enough, you won't be turning the volume up to hear the quiet bits which would otherwise be masked by noise (signal-to-noise ratio of 70dB is fair, 80dB is preferred, 95dB is more expensive). Where the noise floor is, is a design decision to be made (NC 100 noise floor is really cheap [paper bag], NC 5 noise floor is extremely expensive [demolish your house and start over]). If you're practically deaf, and play everything loud all the time, you can also have a higher noise floor.
The THX ratings are something like: "The steady-state theatre noise floor should preferably be below NC25, with NC30 the worst case acceptable. Intermittent increased noise floors should not exceed NC35."

How quiet is the room now? Can you hear aircraft, bus/truck traffic, hvac/plumbing/dishwasher? Put a boom box (portable CD player) on a chair on the patio, and measure the sound loss. Put a subwoofer in the basement, and measure the sound in the room to determine the transmission loss through the fire door. If the sound transmission loss is already high enough to knock the central heating blower's basement noise under your noise floor, then that's great.

If you put a subwoofer into the room and play it loud [90db @20-70hz], can you hear it in your house, particularly the bedrooms? Do the kitchen dishes rattle? Do the neighbours hear it?

If you can't hear outside noise, and the outside can't hear you, then you're already done soundproofing, except for hvac (which is both a noise transmission conduit, and a source of wind/blower noise).

In otherwords, measure what you have now, then engineer what you're going to do to fix it. If the diagnosis is that you're already fine, then do naught.
I think Ted at sound proofing company said that concrete was very good at transmitting sound waves far and wide i.e. my flanking comment. Now that we know you have a bunker it may make it worse than better. For sure I cannot answer this but I think the tests Basement Bob mentioned are worth a try. I am just wondering if putting insulation or ridged fiber board between your concrete T beams would help? Correct me your height is already limited so room in room is out?
post #173 of 351
Quote:
Originally Posted by elmerfudII View Post

Is it better to tear out the existing ceiling and insulate between the joists and then put up an isolated ceiling or leave the existing ceiling in place and put up a sub ceiling and insulate between the two ceilings ?

Thanks
I think this is the only way to go but you can reuse the DW you take down if you are careful in the demo. Use two layers with green glue in between make sure you only use 1 1/4” screws on first layer and 1 3/4” screws on second layer or you will couple it to your hard wood above. R 19 in the ceiling joist than IB-1 clips, hat channel, and two layers of 5/8" DW with GG You will need to decouple the walls as well. Sound proofing is an all or wasted your money doing half kind of thing.
post #174 of 351
Quote:
Originally Posted by cw5billwade View Post

but you can reuse the DW you take down if you are careful in the demo.

This is something I would need to see to believe. IMHO drywall is one of the cheapest building materials and not worth the time trying to remove each piece intact.
post #175 of 351
Thread Starter 
Quote:
Originally Posted by elmerfudII View Post

The basement has 9 foot ceilings with 1/2" lightweight drywall on them. The main floor has good quality 3/4" plywood underlay covered with brazilian cherry hardwood. There is no rug anywhere on the main floor. The floor joists are about 16" tall. There is no insulation between them.

So... is there an easy way to soundproof the basement ceilings without ripping them out and starting over ?

Is it better to tear out the existing ceiling and insulate between the joists and then put up an isolated ceiling or leave the existing ceiling in place and put up a sub ceiling and insulate between the two ceilings ?

You actually have quite a few options. Yes, one of the options is to just drywall over the existing ceiling (with Green Glue) and that will help a little. You're going to get a lot more bang for the buck if you take that (very cheap) layer of drywall down, though. Here's a good lineup of treatments that you can do, along with how effective they are: How to Soundproof a Ceiling

But the fact that you have 9 ft ceilings brings up another possibility. If you don't have a lot of stuff between the joints (pipes, HVAC, etc), then you always create a set of "floating" joists in between. That is, you would create an interior set of walls that don't touch the outside walls and then put new joists resting ONLY on those walls. They would be between your current joists and dropped down by an inch or so. That's the absolute gold standard for sound insulation, and it would only cost you a few inches.

Some details here: Building a Room Within a Room
post #176 of 351
Thread Starter 
Quote:
Originally Posted by BIGmouthinDC View Post

This is something I would need to see to believe. IMHO drywall is one of the cheapest building materials and not worth the time trying to remove each piece intact.

Seconded. I'm a big proponent of "deconstruction" as opposed to "demolition" and reuse and recycle as much as I can. But I draw the line at drywall. I attempted to save it during my first major renovation and the found that while yes, it is theoretically possible to save some of the drywall (mostly if it's screwed and not nailed), it's not even CLOSE to worth it. Those panels would need to be ~$100 each to justify the hours you'd waste dealing with them.
post #177 of 351
Quote:
Originally Posted by BIGmouthinDC View Post

This is something I would need to see to believe. IMHO drywall is one of the cheapest building materials and not worth the time trying to remove each piece intact.

You guys are right that drywall is cheap, but the labor to put it up, tape it, sand it and paint it certainly isn't ! Having just done a whole bunch of small drywall jobs in the house, its a major pain to hire people to do drywall.

Having said all that, I think you guys are right that the ceiling needs to come down.
post #178 of 351

Hi there cw5billwade

I have attached a cross section of this basement project - you can see that the basement has been constructed as a complete stand alone structure. It is free standing and has lose pea gravel and polystyrene insulation on all four walls to take away any water etc. Have a look see and then maybe we can agree as to how one should proceed.

 

As for noise transmission - All I can say is that if I tied you up and locked you in the basement I doubt you would ever be heard. We are talking about 300mm of blockwork and insulation all round....

On top of the patio have a basalt tile system which sit on plastic feet to allow the rain to permeate to the waterproof membrane (Paint and then 

 

 

concrete screed) So there will not be any transmission of sound downwards. The only potential area for sound coming into the theatre is the MVHR (Mechanical Ventilation and Heat Recovery / Air Conditioning). But I have done a sound test and on the low setting I can not hear the fan which is isolated by a flexible insulated baffle.

 

So all up I am pretty happy about the sound proofing. What really interests me is given that I have to build the floor I would like to know what treatment I can incorporate in the design to deaden any potential unwanted sound /echo coming from the speakers.

post #179 of 351
Quote:
Originally Posted by BIGmouthinDC View Post

This is something I would need to see to believe. IMHO drywall is one of the cheapest building materials and not worth the time trying to remove each piece intact.
LOL I know but I did say CAREFUL!
post #180 of 351
marvoroberts:
It really is a bunker then. I need one of them at my house but for tornados. I think that standartd building practices for the floor using presure treated lumber for the riser and stage if you build tem is all you need check Stockmonkey200's Desert Sunset Theater build. he did a really good job documenting his floor during his build. Then check out the Acoustical Treatments Master Thread, . you will diffently need som deading from reverberation.
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