Hi there. I'm new to this site and quite frankly I am overwhelmed with the amount of useful info. Unfortunately the construction of my project has already started and I'm afraid I don't have time to sift through everything in time to prevent my contractor from making an irreversible mistake.
I am building a soundproof recording room in my basement. The soundproofing goal is to stop the sound from getting into the room from the outside (rather than from inside out). The two major noise sources are the furnace/ac/water heater and the first floor above (foot steps). The basement is approximately 24' x 24' x 8.5'. There is a metal I-beam running through the middle of the room at about 7' height and 2 metal poles supporting it.
To combat the furnace/ac/heater noise we are building a wall closing off the space with the utilities. Originally the wall was designed as follows (from the outside in):
drywall/resilient channel/2x4 wood stud with IIG MinWool insulation/resilient channel/mass loaded vinyl/drywall
I spoke to some experts and was told that RC should be only on one side of the wall. The design was revised as follows (from the outside in):
drywall/RC/2x4 wood stud with IIG MinWool/drywall/MLV/drywall
My first question is: is this the most efficient wall design given the materials used? Would another configuration be more efficient? Would Green Glue in place of the MLV yield better results? Feel free to suggest different materials/configuration (keep in mind the stud frame has already been completed).
To combat the noise from the footsteps on the first floor above we are building an independently suspended ceiling. The studs are suspended from two concrete walls and the I-beam in the middle. They are wood 2x4' 12' long on one side and (I believe) 10' long on the other. They are not touching the joists of the first floor. The initial ceiling design was as follows (from top to bottom):
2x4 wood stud
drywall
MLV
RC with an air gap
drywall
When I was ordering MLV I was told that having an air gap like that is a no-no because it would create a reverberation chamber and actually make things worse. The revised design is as follows (from top to bottom):
2x4 wood stud
MLV
RC with an air gap
drywall
Green Glue
drywall
My second question is: which design is more efficient? Given the materials described is this the best configuration? Is there a way to improve it using other materials and/or a different construction?
The problem is the construction has already begun. The contractor has built the frame for the wall and the ceiling and the electrical wiring and air duct work has been completed. I know we already didn't do it right - should have nailed several layers of drywall between the joists of the first floor. Too late for that. I have halted the construction until I find out the right way to do this but I can't put it off for long. A prompt answer would be greatly appreciated. Once again, the goal is to stop the sound from going into the room. The budget for the special insulation materials (MLV/GG) is about $2000. I could spend more if absolutely necessary.
Thanks much
Please help me with my walls and ceiling. Urgent.
Originally posted at johnlsayers.com, topic 12367.
I suggest you to STOP , and make a safe and clear plan of your construction. You could be wasting a lot of money and as I see in your first lines, you are building a 3 leaf system which is NOT any good.
Please stop and design your studio carefully
Yes, I did stop. I just can't hold it for too long. I appreciate your reply although I would like to see more specific recommendations. Such as given the materials I listed in the post how would you suggest I use them to maximize the sound coming into the room. Thanks.I suggest you to STOP , and make a safe and clear plan of your construction. You could be wasting a lot of money and as I see in your first lines, you are building a 3 leaf system which is NOT any good. Please stop and design your studio carefully
cancel the mass loaded vinyl if its not too late. mass is mass. MLV is very costly mass and there are many much cheaper alternatives.
also you MUST search 2 leaf wall constuction and know how critical it is.
very basically a 2 leaf wall is: leaf one: mass (layers of drywall on 2x4 framing)
air: air cavity with insulation in all framing)
leaf two: mass (layers of drywall on separte 2x4 framing)
ideally there is no connection at all between leaf one and two, and no air pockets or air gaps in the layers of drywall for each leaf. Each layer of mass is air tight.
Adding a third leaf makes isolation worse.
I haven't ordered any of the materials yet (except for some minwool fiber insulation that my contractor already got). I thought that one of the main properties of the MLV is it's limpness. And that's something that would enhance significantly the performance of the wall/ceiling. Am I wrong? Actually I am a lot more concerned with the ceiling than with the walls. Unfortunately I can't make 2 2x4 framings for the ceiling. It's already down to 6' on one side. Could you suggest the best way to configure the ceiling on an independent single 2x4 frame? Most likely we can't place anything on top of the studs - there are air ducts that come within 1/4" to the studs. The construction needs to be under the studs. I can see losing another inch or even a couple of the ceiling height if it makes things significantly better. Please post your suggestion. Thanks much.cancel the mass loaded vinyl if its not too late. mass is mass. MLV is very costly mass and there are many much cheaper alternatives. also you MUST search 2 leaf wall constuction and know how critical it is. very basically a 2 leaf wall is: leaf one: mass (layers of drywall on 2x4 framing) air: air cavity with insulation in all framing) leaf two: mass (layers of drywall on separte 2x4 framing) ideally there is no connection at all between leaf one and two, and no air pockets or air gaps in the layers of drywall for each leaf. Each layer of mass is air tight. Adding a third leaf makes isolation worse.
1 :add airtight mass to floor assembly above up between joists ( or from upstairs laid onto the floor if that is a possibly)
2 install new ceiling joists isolated from the rest of the structure suppoted by the new framing for the room walls (your metal I beam is not isolated and neither are your cement walls which will lessen isolation)
3; insulation
4:add air tight mass to the new ceiling studs.
or, hang new ceiling mass onto some sort of islation hangers or resiliant channel attatched to the existing structure instead of the new ceiling joists.
in both cases make sure the structure can handle the load added or you risk a collapse. A structural engineer is needed to tell you how much mass you can add.
You seem to be getting plenty of good advice already, so I'll just echo what others are saying, and add my 2 cents worth:
Forget the MLV. Drywall is much cheaper per unit of mass, and what you need is just mass.
Correct. Well, you COULD put it on both sides, but it would be a waste of money. The purpose of RC is to decouple one side of the wall from the other. If yo put RC on one side of the studs, then the entire wall is already decoupled. Putting more RC on the other side won't gain you anything.I spoke to some experts and was told that RC should be only on one side of the wall.
I'd make it: drywall - drywall - RC - studs with wool - drywall - drywall.drywall/RC/2x4 wood stud with IIG MinWool/drywall/MLV/drywall
Then they aren't actually suspended! :) Since the are in contact with both the I-beam and the walls, they are fully coupled, and will therefore flank. There are several methods you could use to do what you want, but probably the easiest in your case is to take down that wasted wood that isn't doing you any god at all, beef up the underside of the floor above, put RC across the existing joists, fill the air space with mineral wool or fiberglass, attache 2 layers of 5/8 drywall with Green Glue in between. Seal. done!The studs are suspended from two concrete walls and the I-beam in the middle.
It doesn't matter if they are directly touching or not: they will still flank, since they are touching the I-beam and the walls. Also, a 12 foot span sounds like an awful long distance for simple 2x4s that is going to have a lot of weight hanging from it! Did a structural engineer give you the OK for that?They are wood 2x4' 12' long on one side and (I believe) 10' long on the other. They are not touching the joists of the first floor.
True, but not just because it creates a resonant cavity: also because you need several inches of air gap behind RC in order for it to work. A thin gap like that is basically useless. The revised design is as follows (from top to bottom):When I was ordering MLV I was told that having an air gap like that is a no-no because it would create a reverberation chamber and actually make things worse.
That's just as bad! Your air gap there is the thickness of the RC! No use. You need about six inches of air gap for optimum isolation with RC. Once again, dump the MLV, use drywall strips to beef up the underside of the floor above, fill the air gap with wool, put the RC on the studs, and hang two or three layers of 5/8 drywall. Or better yet, build a proper "room within a room", where the ceiling rests on the inner leaf and does not touch the outer leaf at all.2x4 wood stud MLV RC with an air gap drywall Green Glue drywall
For ISOLATION, mass is mass. The higher the density, the better. It doesn't matter how that mass is made, as long as there is plenty of it, and very dense. The sound waves don't care how much you paid for the mass! All they see is mass. The mas that you get in a sheet of drywall is an awful lot cheaper than the same amount of mass in a roll of MLV. Do the math. Now, if you were building some kind of limp membrane acoustic treatment within your already-isolated room, then I guess MLV might be of some use. But it doesn't help much for isolation. Isolation and treatment are two entirely different things.I thought that one of the main properties of the MLV is it's limpness. And that's something that would enhance significantly the performance of the wall/ceiling. Am I wrong?
You could build it inside out! By that, I mean that your ceiling can sit on top of your inner-leaf walls, but put the drywall on TOP of your new ceiling joists, instead of underneath it. That gives you the space between the studs for room TREATMENT, which you will need anyway, so in effect it gives you several inches of extra headroom., for FREE! :) But the best advise of all came from petrovinksy: "...make sure the structure can handle the load added or you risk a collapse. A structural engineer is needed to tell you how much mass you can add." Absolutely! You need a structural engineer to tell you if you actually can hand all that extra mass from your existing structure. - Stuart -I can see losing another inch or even a couple of the ceiling height if it makes things significantly better. Please post your suggestion.
Stuart, thank you for such comprehensive reply. That's a lot to re-think and re-do. My budget is really stretched as it is and I don't know if I can afford undoing what has been already done (including the HVAC and electric jobs). But I will talk it over with the contractor. A couple of days ago I collapsed with a flu and still haven't recovered. I will post more after I discuss this with the contractor.
If I understand you correctly you're suggesting a one-leaf construction. Wouldn't a 2-leaf construction be more effective? What other methods I could use to do what I want?There are several methods you could use to do what you want, but probably the easiest in your case is to take down that wasted wood that isn't doing you any god at all, beef up the underside of the floor above, put RC across the existing joists, fill the air space with mineral wool or fiberglass, attache 2 layers of 5/8 drywall with Green Glue in between. Seal. done!
Actually, what I described above really is a 2-leaf system: The RC (resilient channel) decouples the drywall from the joists, which makes it into two leaves. It would be one leaf if you did not use RC, or if you used hat channel by mistake, instead of RC, or if you used battens of some kind, or anything else that does not decouple. It has to be proper RC in order to work, or it can also be hat channel PROVIDED THAT you attach the hat chanel with RSIC clips. Hat channel will not work on its own. RC will.If I understand you correctly you're suggesting a one-leaf construction. Wouldn't a 2-leaf construction be more effective?
The only other method is to hang the new ceiling directly from new inner-leaf walls. That would be even better, since it gives you better decoupling than what RC can give, but it means that you will loose some ceiling height, or you will have to build the ceiling inside-out. - Stuart -What other methods I could use to do what I want?
According to another poster a leaf is mass. Is it not so? And then RC would be used to decouple one leaf from the other. I definitely need two layers of mass with an air gap in order to silence the foot steps from above. Would this work (from top to bottom): RC (across the floor joists) drywall green glue drywall 2x4 battens RC drywall green glue drywall Also what do you think of http://www.kineticsnoise.com/arch/icw/index.aspx or http://www.kineticsnoise.com/arch/ksch.aspx instead of the RC (for suspension from the floor joists)?Actually, what I described above really is a 2-leaf system: The RC (resilient channel) decouples the drywall from the joists, which makes it into two leaves. It would be one leaf if you did not use RC, or if you used hat channel by mistake, instead of RC, or if you used battens of some kind, or anything else that does not decouple. It has to be proper RC in order to work, or it can also be hat channel PROVIDED THAT you attach the hat chanel with RSIC clips. Hat channel will not work on its own. RC will.
How would you construct the ceiling in this case? (top to bottom) Thanks.The only other method is to hang the new ceiling directly from new inner-leaf walls. That would be even better, since it gives you better decoupling than what RC can give, but it means that you will loose some ceiling height, or you will have to build the ceiling inside-out.
existing flooor above leaf 1
RC (across the floor joists) leaf 2
drywall
green glue
drywall
2x4 battens leaf 3
RC
drywall
green glue
drywall
^^^^ you don't want this ^^^^^^
you want this::
Leaf 1:
existing floor above
as many layers of drywall as the
structure an safely carry attatched directly to floor above.
(up between joists against bottom of floor)
Air: between joists filled with insulation
Leaf 2:
layers of drywall with green glue if desired.
hung on Resiliant channel on existing joists or new ceiling joists supported by the new walls.
The floor above is the main source of the noise I am trying to block out. I don't think it should be considered a leaf. Even if I manage to beef it up with several layers of drywall (which is questionable and in some places simply impossible) it still will produce noise when stepped on (mainly low frequencies). I am trying to build a 2-leaf structure that will block out the foot steps. Any suggestions?you want this:: Leaf 1: existing floor above as many layers of drywall as the structure an safely carry attatched directly to floor above. (up between joists against bottom of floor) Air: between joists filled with insulation Leaf 2: layers of drywall with green glue if desired. hung on Resiliant channel on existing joists or new ceiling joists supported by the new walls.
Azzzy, I built a room years ago based on what I "thought". It didn't turn out well.I don't think it should be considered a leaf. Even if I manage to beef it up with several layers of drywall (which is questionable and in some places simply impossible) it still will produce noise when stepped on (mainly low frequencies).
azzzy,
Impact noise is your issue. Maybe you just require someone to say what has already been said with more authority.
Produced by the U.S. Department of Housing and Urban Development:
http://www.toolbase.org/Building-System ... ors-stairs
Page 19 goes directly to what you are dealing with and why with the same suggestions to correct it. If it still isn't enough...then you will just have to read David Harris book, Noise Control Manual for Residential Buildings, for yourself.
It takes a lot longer and the same answer will still come back at you;)
Hope this helps.
I am sorry, but how is this relevant to what I said? Did you think the same thing as I am thinking now? Which is that two layers of mass with an air gap in between is better than one layer of mass? If something is the source of the noise how can it be considered a leaf in the soundproof system?Azzzy, I built a room years ago based on what I "thought". It didn't turn out well.I don't think it should be considered a leaf. Even if I manage to beef it up with several layers of drywall (which is questionable and in some places simply impossible) it still will produce noise when stepped on (mainly low frequencies).
Thank you for the link. Unfortunately page 19 (as well as the whole guide) is geared towards rebuliding the house, which in my case is simply impossible. I can't rebuild the floor - not enough money. My only choice is to build a barrier between the impact noise from the floor above. From what I understand (in large part from reading around on this site, as well as from my own common knowledge) two layers of mass with an air gap would be more effective than a single layer of equal mass. Is this not correct? Now I need to figure out how to construct those layers/leafs and how to suspend them underneath the ceiling. My choices for suspension are 1. the way it is done now - directly from the concrete walls into the I-beam in the middle of the basement, 2. from the floor joists using RC or other (more expensive) suspension devices I mentioned in an earlier post. 1. I think that the concrete walls and the steel I-beam are stiff enough not to transmit the impact noise from the wooden floor. I, of course, may be wrong. Besides the whole structure built at the moment does not instill confidence as to its ability to carry the weight. However if that's the route I can go I need to know how to layer the drywall/MLV/RC/2x4/GG, etc. 2. Sounds like that's actually a better way to go. Definitely more secure (although that adds more stress to the floor itself). It will cost me a lot more money (because I will have to take down what's already been built and pay extra to re-do the electrical work) but if I am assured that the way #1 is not going to yield the results I need, I will spend the extra money. Still I need to know how to layer the materials, whether I can use RC for the first leaf (counting from up to bottom), then 2x4 battens and RC for the second leaf.azzzy, Impact noise is your issue. Maybe you just require someone to say what has already been said with more authority. Produced by the U.S. Department of Housing and Urban Development: http://www.toolbase.org/Building-System ... ors-stairs Page 19 goes directly to what you are dealing with and why with the same suggestions to correct it.
My contractor has a very good idea of what to do when it comes to residential buildings. Alas noise levels acceptable in residential spaces make a recording space completely useless.If it still isn't enough...then you will just have to read David Harris book, Noise Control Manual for Residential Buildings, for yourself.
What exactly is the answer? To hang a single layer of mass (drywall/GG/drywall) with RC and seal it? That's not going to be enough. To rebuild the house? Not going to happen due to financial issues. So... what is the answer?It takes a lot longer and the same answer will still come back at you;)
What kind of floors ya got upstairs? (wood, tile ,carpet??)
and you got me thinking. If the noise source originates from the first leaf of a 2 leaf system (stomping on the floor) wouldn't it only be the second leaf blocking the sound???? hmmm.....
but if the same noise source (stomping) originates from leaf one of a three leaf system with the second and third leaf fairly close together (less than 4" as proposed in your details) would the isolation of the sub 200hz be better, worse or the same??
Hardwood. And that cannot be changed.What kind of floors ya got upstairs? (wood, tile ,carpet??)
I'm not sure if you're asking me or everybody else (I hope the latter). I am thinking of a revised construction described in an earlier post. Let me recap. There are 2 versions possible. The first would be utilizing the 2x4 frame that's already built from the concrete walls to the I-beam (from top to bottom): MLV 2x4 battens with insulation RC Drywall Green Glue Drywall The second version would be suspended from the floor joists via RC or springs http://www.kineticsnoise.com/arch/icw/index.aspx (from top to bottom): RC or springs Drywall GG Drywall 2x4 battens with insulation RC Drywall GG Drywall What do you guys think?and you got me thinking. If the noise source originates from the first leaf of a 2 leaf system (stomping on the floor) wouldn't it only be the second leaf blocking the sound???? hmmm..... but if the same noise source (stomping) originates from leaf one of a three leaf system with the second and third leaf fairly close together (less than 4" as proposed in your details) would the isolation of the sub 200hz be better, worse or the same??
azzy - this is the simplest and cheapest way to isolate a basement studio from the upper floor.
It's called an inside/out ceiling in that the ceiling frames are made on the floor, drywall layers added, then it's lifted up into place atop the outer walls. As you can see nothing touches the upper floor PLUS you end up with a treated ceiling which is always a problem in basements because they are so low.
here's a pic of how it comes out - this is a studio in Cyprus before the cloth was added.
John, thank you very much for replying to my thread. This is kinda what we were striving towards (except we did it backwards). I do have a few questions: How do I make a free standing wall? We do have soundproof walls put up (to isolate the AC/furnace/heater) but they are anchored to the concrete walls on the sides. How do I make it not touch anything but the floor? Won't it collapse? My room is about 24' x 18'. Do we construct the entire ceiling on the floor or is it done in sections? How do we get it up? Is there somewhere on this site where I could read about the process in detail? There is a steel I-beam running in the middle of the basement. 7' high (I think). We will have to build a soffit around it and some air ducts/pipes that run underneath the floor joists. Would you suggest orienting the battens along the I-beam? Or is it OK to run them across the I-beam and to anchor them on the concrete walls and the I-beam? The beam and the concrete walls are stiff and massive and I don't think they will transmit much of the impact noise from the hardwood floor above. What kind of insulation would you recommend? My last question is: if I can afford extra expense, for soundproofing purposes would it be better to use two layers of drywall with Green Glue in between suspended on RC instead of the cloth for the bottom leaf? Would mass loaded vinyl be better than cloth? I am not too concerned with the treatment for the ceiling. Besides it's supposed to be a finished basement for generic purposes as well and I expect my girlfriend (whose house this is) would strongly protest against it. Thank you very much for your input.azzy - this is the simplest and cheapest way to isolate a basement studio from the upper floor. It's called an inside/out ceiling in that the ceiling frames are made on the floor, drywall layers added, then it's lifted up into place atop the outer walls. As you can see nothing touches the upper floor PLUS you end up with a treated ceiling which is always a problem in basements because they are so low.
check out this thread - it's all inside/out :)
http://johnlsayers.com/phpBB2/viewtopic.php?f=11&t=6968
It is a leaf, no doubt about that! The entire set of "mass-air-mass-air-mass" acts together as a tuned SYSTEM, not as individual parts. The entire system has a resonant frequency at which it is not only transparent to sound, but actually boosts sound transmission. at roughly 1.4 times the resonant frequency the entire system is merely transparent to sound, and at roughly twice the resonant frequency it starts isolating sound decently. So clearly, you MUST create a system where the resonant frequency is as low as possible, and well outside the range of human hearing, so that twice that frequency is the lowest frequency that your system needs to isolate. If you have three leaves in your system, then that INCREASES the resonant frequency, which is something that you do NOT want to do. If you increase the resonant frequency of the entire system by adding a third leaf, then there are only two ways open to you to get good isolation: Increase the size of the air gaps considerably, and increase the mass considerably. so if you have your heart set on building a three-leaf system, then I'd suggest that you need to at least double your air gaps, to leave 8 inches between your sub-floor and second leaf, then another 8 inches from their to your third leaf, and also to double the mass of each of those extra leaves. That would roughly compensate for the higher resonant frequency that you will be creating by making it into a three-leaf system. Plus there is also the matter of the huge amount of mass that you would be adding to your floor: how much more load can it take? What did your structural engineer say when you asked him if it is safe to add tons of extra load to that floor? On the other hand, what you could do for a lower total cost and much less loss in ceiling height, is to just build a two-leaf system, like everyone here has been suggesting, which intrinsically has a much lower resonant frequency. In your case, one of the leaves is a source of impact noise, so you need to isolate your second leaf really well, and you also need more mass on BOTH leaves, a larger than normal air gap, and plenty of insulation in the air gap.The floor above is the main source of the noise I am trying to block out. I don't think it should be considered a leaf.
What stuntbutt was trying to say, I suspect, is that just "thinking" that something might be so is not a good way to design a studio: you need to make certain if it actually is so, not just think that it is so. The issue here is that the entire set of components acts together as a tuned circuit, not individually, which is what you "thought". If you open up a radio and decide to add an extra capacitor to the tuning circuit, since you "think" it will help to make your reception better, all that you will succeed in doing is tuning it to a totally different band. The capacitor by itself, as a single component, does nothing. But as soon as you add it to the circuit, it becomes part of the system and affects the way that system works. Adding a third layer to your ceiling is exactly the same as adding a capacitor to your radio tuner: it changes the frequency response of the entire system.I am sorry, but how is this relevant to what I said?
Built is as ONLY two leaves (not three, which is what you are proposing), build it as a totally decoupled structure, build it with a lot of extra mass (more than normally recommended here), and build it with a large air gap (more than normal) that is totally full of insulation. Nothing else will work as well at a reasonable cost. There are other ways to solve your problem, but they are not cheap, and you would not like them anyway, I think!Even if I manage to beef it up with several layers of drywall (which is questionable and in some places simply impossible) it still will produce noise when stepped on (mainly low frequencies). I am trying to build a 2-leaf structure that will block out the foot steps. Any suggestions?
That is correct. The only place where you are going wrong is thinking that the existing leaf is not actually a leaf, when in fact it is. so you only need one additional leaf, not two.From what I understand (in large part from reading around on this site, as well as from my own common knowledge) two layers of mass with an air gap would be more effective than a single layer of equal mass. Is this not correct?
Correct: you are wrong. :) Stiffness does not PREVENT impact noise from traveling through a medium. In fact, the opposite is true: Limpness damps transmission, stiffness increases it. If you tap on a steel beam with a hammer, then you can hear that sound on the beam a really, really long way away, precisely because the steel (which is much stiffer and denser than wood) transmits the sound really well, and really fast. You really can hear a train coming from MILES away, if you put your ear to the track.... How many miles of steel beam do you think it would take to stop sound getting through your floor?1. I think that the concrete walls and the steel I-beam are stiff enough not to transmit the impact noise from the wooden floor. I, of course, may be wrong.
MLV??? Why would you want to use MLV? Didn't you say that money was an issue, and you did not want to waste it? 2x4? There is no way on this planet that 2x4s are going to support the kind of mass you are talking about here. 2x6, 2x8, 2x10, or something like that is what you will need. Once again,m your structural engineer will tell you what dimension you need to use for the load that you need to carry.However if that's the route I can go I need to know how to layer the drywall/MLV/RC/2x4/GG, etc.
Really? Why are the laws of physics not going to be enough for your build? Please could you explain why a decoupled two-leaf MSM system will not work in your case, whereas a fully coupled three-leaf system will work. I'm finding it hard to understand the logic in that. You might well need several more layers of drywall on that second leaf, and a larger air gap, but the basic MSM principle is what will make it work. Decouple the leaves fully, use a large air gap that is fully damped with 48 kg/m3 insulation, and put plenty of mass on each leaf. The laws of physics will work just as well for you as they do for anyone else.To hang a single layer of mass (drywall/GG/drywall) with RC and seal it? That's not going to be enough.
Worse. The whole is greater than the sum of its parts. The entire structure acts as a single tuned system. The parts do not act on their own. Changing any of the parts changes the tuning. Adding a third leaf is like adding an extra inductor and capacitor to an existing tuned circuit: it will not necessarily change the total resistance (impedance) of the circuit, but it most certainly will change the tuned frequency and the roll-off.but if the same noise source (stomping) originates from leaf one of a three leaf system with the second and third leaf fairly close together (less than 4" as proposed in your details) would the isolation of the sub 200hz be better, worse or the same??
Why do you want to decouple twice? I also doubt that your top RC will be able to handle all that mass that you are proposing to hang below it... And once again, you say that the existing joists are only 2x4, so there just is no way that they will be able to handle the huge additional load that you are planning to hand from them.RC or springs Drywall GG Drywall 2x4 battens with insulation RC Drywall GG Drywall
No, that would create a third leaf, which would increase the resonant frequency of the system, as described above, thus making your low frequency isolation worse, not better. In John's design, the cloth is not a leaf anyway: it has negligible mass and is acoustically transparent. It is only there for aesthetic purposes, and is not a leaf at all.My last question is: if I can afford extra expense, for soundproofing purposes would it be better to use two layers of drywall with Green Glue in between suspended on RC instead of the cloth for the bottom leaf?
No, that would cost you a lot of money and would create a third leaf, ditto above. The cloth is not a leaf.Would mass loaded vinyl be better than cloth?
Then just build a normal fully decoupled "room within a room", and build it the "right way out" instead of "inside out". That will accomplish what you want, provided that you make it massive enough and leave a large enough air gap. - Stuart -I am not too concerned with the treatment for the ceiling. Besides it's supposed to be a finished basement for generic purposes as well and I expect my girlfriend (whose house this is) would strongly protest against it.
"How do I make a free standing wall?"
Build the frame on the ground. square it. add dry wall. get a bunch of mates to lift into postion. then Dynabolt it to the ground.
I had my 3x 5m wall standing up right for a week before I got th next walls into place. I added a saftey rope attached to the above ceiling, just in case :wink:
check out song cave studios build- his ceiling was built in sections on the ground then raise and screwed into place, with alot of acoustic caulk