- rebuilding the floor...what layers to build there? 1" plywood + mass load vinyl and seal everything?
Before even thinking about any of that, there's still the basic underlying question that hasn't been answered yet, and is the basis for EVERYTHING you are talking about for your studio. The question is: "How much isolation do you need, in decibels?". Without knowing the answer to that question, you won't be able to get any answers.
Let me re-phrase this in terms of you wanting to buy a car. So you go to a dealership, and start talking to them about your love for tinted windows and leather upholstery. When the salesman asks you what type of car you are looking for, you tell him that rubber floor mats are out and you only want carpet. When he tries to refine things, and says "But are we talking about a 2 seater sports car? Family sedan? SUV? Truck?", you answer by telling him that the front seats must be heated, and there must be cup holders all over, as you like to drink stuff while you drive. When he says: "But how many people to you want to drive around in your car?" you reply with a comment about how the glove compartment needs to be large, as you often need to put lots of stuff in there, and the color cannot be dark, as that would make it too hot in summer.
I'm not sure if you get my point, but until you answer the most basic question, nobody can help you!
Just like the exasperated car salesman cannot show you any cars until you tell him what you really need, so too we cannot help you with any questions about how to build your room, what materials to use, how to treat it, where to put things, or any other aspect, until you tell us what you need. Isolating a room for 40 dB or for 60 dB are two totally and very, very different things: As different as a Prius is from a Ford truck.
So I'd urge you to go back to the first few posts on your thread, and answer those questions completely.
Based on that, we'll be able to give you more useful, intelligent, sound, solid advice on how to build it.
The only thing I can tell you so far, is stuff you are doing wrong.
- glue, screw and seal the existing floor (actually is now just a raw sub-floor);
Don't do that until you solve your squeak problem. Solving it might require pulling up the sub-floor....
maybe add a layer of mass-loaded vinyl to seal it even further
Why? The purpose of MLV is not to seal things: it is to add mass. That's what that name implies: "MASS Loaded Vinyl". And very expensive mass it is, too! Pound for pound, it's one of the highest cost methods for adding mass, and covering that area with MLV will cost a small fortune. Why are you not able to add mass with less expensive materials? Why are you not able to seal with more suitable materials?
- the existing wall's drywall will be relocated to an improved mass on the outer leaf -
Does that mean that you are planning to take off the drywall that faces the room, cut it into strips, and use those to "beef up" the other side of the wall, in between the studs, with caulk sealing all around the edges, and cleats nailed sideways into the studs? If so: good, but how many layers of drywall do you need in there in order to get the correct MSM resonant frequency and isolation characteristics that you need in order to get the amount of isolation that you need, in decibels? You DID calculate all that, right? You aren't just guessing randomly, right?
acoustically sealed and upgraded insulation
In what way do you plan to "upgrade" the insulation? What type of insulation will you be using? What density? Why did you choose that type and density? Was it for thermal reasons, or acoustic reasons? If acoustic, what is the gas flow resistivity of the insulation you have chosen how thick will it be, and what damping effect will it have on the MSM resonance?
- a new inner leaf will be installed - isolated from the floor below and existing ceiling structure
Why do you want to float your inner-leaf walls? That's a rather expensive and complicated thing to do: While it is possible, there's lots of careful calculation and design that you'll need to do to get that right. If you make a mistake, then the wall will not float, and you will have wasted a lot of time, money, and effort on nothing. For example, if you get your mass calculations wrong, and overload the resilient material, then it will compress and deflect beyond its resilient limits, "bottom out", and not isolate. If you get it wrong the other way, and "underload" it so that there isn't enough deflection to even reach the resilient isolation range, then it will "top out", not float, and not isolate. Unless you do the math carefully, and check your assumptions with real tests of the materials, then the chances are REALLY good that it won't float.
I also don't understand the question about how to isolate the inner-leaf walls form the outer-leaf ceiling: Since the inner-leaf walls cannot even touch the outer-leaf ceiling at all, why would you need to do anything additional to isolate them? The inner-leaf walls can only touch the inner-leaf ceiling, but never the outer-leaf ceiling.
- a new floating ceiling will be hung from the existing ceiling with RISC hangers and hat channel,
Why? How did you determine that this plan will give you the amount of isolation that you need, in decibels? Clearly, if you need enough isolation that you have to float your walls to get it, then your need is for a very high level of isolation. But your plan for the ceiling is only for a rather low level of isolation. So that doesn't make a lot of sense. Why would you isolate your walls for high decibel transmission loss, but only isolate the ceiling for low decibel transmission loss?
That would be sort of like telling the car salesman that you decided you need a truck, but that you only need bicycle wheels on it...
do I need to remove existing ceiling drywall?
If you did not remove the existing drywall from the existing ceiling, then how would you attach the RSIC clips to the joists? And how would you prevent the very high MSM resonant frequency from trashing your isolation completely?
On the other hand, if you
do take off the drywall, then you don't have an outer leaf any more... Ooops!.
- inside the inner leaf space, install a leveled and floating floor -
Floating floor?
Why do you think you need one of those? Do you have the budget to do that? How thick do you pan to pour the concrete? What type of isolation mounts will you use? Mason Industries has some good ones: are you planning to use theirs? Did you do the math to make sure your floor will actually float? Why do you even want to go to all that extreme expense and complication?
Did you read this thread, which talks about how to float your floor correctly?
http://www.johnlsayers.com/phpBB2/viewt ... f=2&t=8173
it will need some leveling anyway, so probably easier/cheaper to flx the level by floating the entire floor by 2" or so, on uboats
Bad, bad, bad idea. You'd waste several inches of precious headroom like that. And floating a floor is NEVER easy, and NEVER cheap. Many thousands of dollars, plus stacks of careful calculations....
I very much doubt that you'd be able to float it at all: You only have a wooden sub-floor down there, and you already have a problem with providing sufficient structural support under it: how much more support would you need in order to handle several tons of concrete?
Again, below is just a simple drop ceiling with tiles
If you have a drop ceiling, that implies an air space. Why not just put a couple of RSJ's in there, above the ceiling tiles, and below the joists? Surely tehre0s enough space in the plenum to do that?
- changing heating from baseboard hot-water heat to in-floor radiant? Tubing? Could it be done?
Yes,it could be done, but why? Would it not be better to have the heating system part of the usual HVAC system, which you will need anyway?
- adding cooling and fresh air system in the ceiling cavity -
What ceiling cavity? You said you wanted to attach RSIC clisp to the existing drywall of the outer-leaf celing, then hang new drywall below that for your inner-leaf ceiling. That means your ceiling cavity is the thickness of the the RSIC clips, which is a a bit more than an inch... you can't get much HVAC ducting into a one inch cavity!
You need to design a proper, complete HVAC system for your room, that takes into account the amount of air you need to move (cubic feet per minute) the speed that you need to move it at (feet per minute), the amount of heat that you need to remove from the room (produced by the equipment, lights, people, etc), the amount of humidity you need to remove (latent heat load compared to sensible heat load) the static pressure, and a number of other things. Lots of calculations go into designing an HVAC system for a studio! You can't just randomly buy a few bits of duct and stick some fans on one end and registers on the other...
can I isolate the exchanger and fans up there?
In a 1" gap?
And what about your silencer boxes? Those are huge anyway...
400 sq foot room = 2 vents? Sizing?
Ummm.... nope. It's rahter more complicated than that...
Your room will be totally sealed air-tight, twice over, absolutely hermetic. No air at all will move in or out unless you force it to do so. No heat will move inor out unless you force it to do so. No humidity will move in or out unless you force it to do so. If you put a few people in there, with their instruments, gear, lights, equipment, etc, them temperature will rise (body heat, electrical heat), the humidity will rise (people exhale moisture in their breath, they sweat, etc.), the oxygen level will decrease (people breath in oxygen an burn it), the carbon dioxide levels will rise (people exhale CO2), and the conditions will become rather unpleasant. You cannot fix that with a couple of ducts and a fan! Studio HVAC is a lot more complex than that...
It seems to me that there's a lot of basic design work that you need to do before you can start on the build. It seems to me that there are an awful lot of grey areas in your design process so far, and they all need to be corrected before you can lift a hammer. A lot of what you are planning to do is not correct, or not optimal, and a lot of it seems to be based on guesswork, rough estimations, and "some guy told me ...". That's not a good way to approach studio design. I'd suggest that you buy and carefully read two books: "Master Handbook of Acoustics" by F. Alton Everest, and "Home Recording Studio: Build it Like the Pros", by Rod Gervais. They will give you the background that you need to know in order to design and build your studio. Once you have read through both of those, then you can start working on the design process,form the start,step by step. a lot of the problems and questions you have will be resolved simply, once you start following the correct procedure.
- Stuart -
