Another Moon Studios

Hello, I have recently started a thread over here at GearSlutz (http://www.gearslutz.com/board/photo-di ... udios.html) about our new house with two existing large-room studios. One of the first questions I have is starting with the floor - it already is squeaky, so I'm assuming I will need to pull it up, glue it and screw it back down. The room below has a drop-ceiling installed, but no other insulation other than that. Thus, the question is how to isolate and insulate layer-by-layer from the drop ceiling below...all the way up to a nice bamboo finished floor on top. I am not currently a professional recording engineer or studio, but that's not to say the future for this space couldn't become a more serious commitment. But, I'd rather get the floor set right before doing anything else because it's the most difficult to change later. The starting room looks like this: Cheers and thank you in advance, -mt [edited: we decided to name our two studios "Another Moon"]

Hi there "MT", and welcome! :) The most important question you need to answer before you can plan this, is simply: "How much isolation do you need?" In other words, how many decibels do you need to stop getting through from the room above to the room below. Once you have an answer to that question, it is fairly easy to figure out how you need to build the floor, walls, ceiling, doors and everything else, in order to get to that amount of isolation. If you don't have a number, then nobody can tell you what you need to do: It's sort of like asking your friends how to get to "the vacation spot", but nobody knows where that spot is! Nobody can tell you how to get there, until you tell them what you want it to be.... :) - Stuart -

Thanks Stuart, I get it! I can imagine once I get into the space I could start taking some measurements, like: - when my wife is rockin' out in the studio below, how much sound (in db) are coming up through the floor? - when the neighbors are mowing their lawn(s), how much sound comes in through walls/windows? - when there's a plane flying overhead, how much sound is coming through the ceiling/skylight? I suppose I should consider getting a simple sound meter for all this measuring, eh? Generally, I read on the forums about the MAM (mass-air-mass) concepts for isolation...I suppose more layers means better MAMAMAM, and thus more reduction? Still reading on this one... -mt

I suppose I should consider getting a simple sound meter for all this measuring, eh?

Right. Decent ones go for about US$ 100 on e-bay or Amazon. But avoid the cheap Chinese junk that goes for around 25 to 50: those really are garbage. Get an Extech, Galaxy, or something like that, in the $100 range. Make sure it has both "A" and "C" weighting, and also "Fast" and "Slow" response. It might have more features, but those are the bare minimum.

Generally, I read on the forums about the MAM (mass-air-mass) concepts for isolation...I suppose more layers means better MAMAMAM, and thus more reduction?

Actually, no: it means LESS isolation, believe it or not! :shock: :!: Adding extra leaves reduces low frequency isolation. Adding extra mass to either of the two leaves in MAM will increase isolation, and making the air gap bigger will also increase isolation. But adding more layers in the manner you mentioned will reduce isolation. Single leaf is terrible, 2-leaf is fantastic, 3-leaf is poor, 4-leaf is bad, 5-leaf is darn lousy.... :) Not intuitive, but very real. - Stuart -

Adding extra mass to either of the two leaves in MAM will increase isolation, and making the air gap bigger will also increase isolation.

That is not intuitive, but perhaps it has something to do with the dissipation low frequencies through different density of matter? The floor joists consist of 2x12" on 12" center, to allow for crossing a huge 21' span without load-bearing posts in the middle of the studio below. Then considering the extra 6" for the drop ceiling - I might have up to 18" of air space between the leaves. Which would leave the next question - how to increase the mass/density of the floor above AND the drop ceiling? Thanks again for the advice! -mt

how to increase the mass/density of the floor above AND the drop ceiling?

Sorry for quoting myself, but I am learning about double leaf construction and it's starting to make some sense. To improve the upper leaf (the underside of the subfloor above the drop ceiling below)...I could add 5/8" drywall with green glue directly to the bottom of the subfloor above. I think the idea is to increase the mass of the upper leaf. But here's the question, considering that the subfloor (above) is very squeaky right now - I'm planning to pull it up completely and then screw it back down. It makes sense that I'm basically starting over from scratch with the floor above then. In the end, I plan to finish with an engineered hardwood or bamboo flooring. I'll keep reading threads... -mt

mtomlins wrote:

To improve the upper leaf (the underside of the subfloor above the drop ceiling below)...I could add 5/8" drywall with green glue directly to the bottom of the subfloor above. I think the idea is to increase the mass of the upper leaf.

That's the right idea. Increasing mass will increase your isolation (if done properly). As Stuart said, you do need to get some idea of what kind of isolation you need/want to start with though. Given that you're pulling up your floor it might be easier to put one, or even two layers of 19mm chipboard flooring down (if possible) and float your bamboo floor over that, rather than trying to beef up the floor from below. It would also allow you to pack and level that floor surface as any of the 'click-lock' systems of floor have a pretty low tolerance for level variation in the surface you're laying them on. Also keep in mind that by doing this kind of retrofit, you're adding considerable weight to a structure that wasn't intended to have considerable weight added to it. It's at this point that you need to figure out how much weight you'll be adding (by figuring out how much isolation you need) and then you might need a structural engineer to confirm the kind of extra load you're looking at. To give you a real world example from my rooms, albeit vertically opposed rather than horizontal. Between them I've got two layers of 16mm Fyrchek plaster on one wall-200mm air gap filled with 24kg per cubic mtr fibreglass insulation-2 layers of 16mm Fyrcheck plaster on the other wall. The rooms are not connected in any way except for the concrete slab and the isolation is excellent. You can hear a little bit of kick and snare from a drum kit but that's about it. I should measure properly but I think i'd be around 55-60DB isolation.

mtomlins wrote:

Which would leave the next question - how to increase the mass/density of the floor above AND the drop ceiling?

If I understandcorrectly, your drop ceiling would be pysically attached to the floor joists of your upper room? This is where you have to be REALLY careful about loading up that structure. one layer of 16mm plaster for your drop ceiling comes in at 13kg per sq mtr. 2 layers is 26kg's. If you've got a couple of extra layers of flooring on top you could be pushing 50kg per sq mtr which is a very significant addition in weight and shouldn't be added without some kind of on-site professional advice. So, I guess it comes back to......how many db's of isolation do you need?

Excellent - thanks...I'll see about calculating total estimated load in the studio above. I'll see about contacting a local architect or engineer to help me see about that. I did confirm with my wife about her plans for the studio below. She might be willing to let me drop a few posts into her space as support. Combined with a cross beam in the middle of the span, that might do the trick. Since this is a project studio and not a professional studio, I have a lot less gear overall. No heavy consoles, outboard gear, etc. Heck, I don't even have a lot of guitar amps and stuff that might weigh a ton. I also don't estimate having live tracking sessions in that room with a large number of people. Better safe than sorry. -mt

Been a little while since an update, and only a little work in the studio. Mostly we've been working on other parts of the house and getting unpacked, settled and returning to our normal selves after that whole endeavor. One important part of the progress in my studio work is on the topic of the bouncy floor - which is nearly 40 years old and needs repair. I have confirmed with several contractors and architects that the structure of the 20-foot span with 2x12" joists at ~12" on center does support the max loads estimated for the studio above. But still there is some annoying bounce in the center of the room. The current direction we're headed is to add "suspension studs" into the design whereby the second floor below is tied into the rafters and ceiling joists above by 4 posts. We would then be adding a beam underneath the floor connecting the 4 posts so as to "cradle" the middle of the floor span. The structural architect estimated that the 1/2" bounce in the floor would be greatly stabilized, but also the maximum load for the floor could be increased by nearly 8x. It seems a conservative estimate given the division of the total span of the floor by 3x and the connectivity to both the roof rafters and ceiling joists above by about 3x. Excuse the rough back-of-the-napkin calculations. Below you'll see the incorporation of the 4 "suspension stud" posts into the layout for the room: And a 3D rendering of the room layout ideas: Sweet Home 3D also gives you "fly through" movies from your rendering, if you're interested: http://i.vimeocdn.com/video/497448288.jpg?mw=480 Of course, I found a used conference table for a console desk on craigslist: As always, your feedback is welcomed on any subject or idea here - especially since I haven't started building anything yet. Thanks in advance, -mt

That sounds like it would be a good solution, structurally, especially if your structural engineer has put his stamp of approval on it. However, it will be very detrimental to your isolation. It will tie the inner leaf very firmly to the outer leaf, so all vibrations picked up by your studio floor and walls will be transmitted directly to the roof, where it will be radiated into the neighborhood. Likewise, and sound vibrations that happen to strike the roof from outside, will be transmitted through this structure into your floor, which already acts like a drum head, and will therefore transmit those sounds into the room, as if it were one huge loudspeaker cone. So any sound outside, such as thunder, rain, wind, overflying aircraft, traffic, dogs barking, lawnmowers, radios, telephones, people talking, etc. could potentially by sent inside your studio, and be radiated by your floor. So I'd suggest you take a serous look at getting that structure hung from isolation hangers, that will support the load just as well but also provide acoustic decoupling to prevent sound from being transmitted though. You will also need to either place those support columns between your inner-leaf and outer-leaf walls for the various studio rooms, or build decoupled soffits around them as part of the inner leaf, to separate them from the outer leaf. You'll probably want to get someone like Mason Industries involved in doing that, as they have the expertise and the products to do it right. They will do all the calculations for you, and recommend which of their products will do the job, and also how they should be installed. This isn't a job for a normal architect or contractor: let the experts handle it. - Stuart -

As always Stuart, you bring excellent advice to your observations. My takeaways from your comments are: 1) as the purpose of the suspension posts is simply to minimize the "bounce" in the floor, we should be careful to not tie them directly into the outerleaf of the whole building - specifically in this case, the roof rafters. If things are tied together then sound vibration will travel right along to the roof and become a giant speaker into the surrounding municipalities. At this point, I am just considering that the larger open room of the studio will be generally sound isolated, but the 2 iso booths be built as rooms-within-rooms (decoupled, separated, sealed). 2) as you state, if it will be necessary to still tie into the roof rafter, consider isolation hangers instead of just bolting directly into the joists/rafters. Since the location of the posts isn't required at specific points for structural load, we have some flexibility in where they are located. We also might just connect to the ceiling joists and not directly up to the roof itself. One of the architects actually suggested running beams above the ceiling joists to tie all the posts together. We could even build a truss in the attic space that distributes support laterally, while not touching the roof at all. 3) since the location of the posts is flexible, I can work them in between the spaces between the walls of the different rooms (in the 'S' of the MSM). I think my next work will be to start adding the double-walls around the layout and work the post locations into that layout. Thanks Stuart - much appreciated! -mt

"The current direction we're headed is to add "suspension studs" into the design whereby the second floor below is tied into the rafters and ceiling joists above by 4 posts. We would then be adding a beam underneath the floor connecting the 4 posts so as to "cradle" the middle of the floor span." If you are fixing a bouncy floor why is a beam underneath that floor, standard procedure, not enough to fix the problem? What does the roof have to do with any of this?

Brien - good question...why not just add a massive multi-lam beam across the center of the floor span below? Simply to avoid having to install posts in the middle of my wife's studio space below. Obviously any additional support for the floor would tie into the surrounding structure - 1st floor, walls or ceiling/roof. We are also considering an alternative design that avoids the ceiling all together and just ties in diagonal truss beams inside the walls as Stuart suggested. Those diagonal beams connecting the walls to the posts to the floors would be decoupled appropriately. (I'm open to suggestions). They might also extend down into the first floor studio, but only at the upper sides of the studio below - and not giant posts in the middle of the span. Thx for keeping the ideas going... -mt

"The floor joists consist of 2x12" on 12" center, to allow for crossing a huge 21' span without load-bearing posts in the middle of the studio below." Ok, I have one dimension, 21 foot span. There has to be another and I am wondering what that is :) A glueLam can span the distance(the unknown distance) and reduce the flex and not require posts. In any event, with a wooden floor upstairs I assume a wooden floor assembly downstairs. This means that IF you had to install load bearing posts on the first floor you would also have to install transfer bearing posts underneath those posts to the Earth. I will add that the one time that "diagonal truss beams" was mentioned was when you did that.

"There has to be another and I am wondering what that is"

<- oh yes, it's nearly square. The joists run 21' across the span, with the other dimension being 25' - with an additional "nook" space as you can see in the layout. Running a large beam under the middle of the floor is complicated. The space below is larger in width than the 25' due to some other changes and additions to that space, including a protruding 10' addition out one end and the home stairway access on the other end (e.g. the door into my studio above is in the middle of a stairway). For the first floor "sun room" protrusion, they already installed a very large beam running about 19' parallel to the 21' joist spans in the ceiling above. The load maximum for that beam would be perpendicular to the 25' beam we would put in the ceiling. That end is compromised already due to there being no contiguous wall connection to carry the load down to the ground. At the other end, there is also no wall underneath to connect the load back to the ground - it's under a stairwell landing that is already constructed with sistered 2x12 joists. The original owners who built the studio addition were a painter (upstairs studio) and a sculptor (downstairs studio). Paintings aren't heavy, so the floor didn't need to be that massive. Sculpture is heavy - VERY heavy, so he used the downstairs studio with concrete floor. Thus, I have the dilemma of wanting to support more load and eliminate bounce in the floor to support a music studio that weighs slightly more than a little old lady and her awesome paintings. As I stated before, the various contractors and architects that have given me tips or advice did clearly state the best options to connect load back down to the ground is limited to 2 parallel walls at either end of the joists on the 21' span. You can carry center load out to those walls with a diagonally connected beam (e.g. equilateral triangle) or up through the ceiling joists and/or roof rafters above the second floor. The triangle truss at the sides of the room seem the most practical to me and probably the strongest way to tie back to the best load bearing walls. My wife even agreed to have some cantilever support from her space below - imagine a diagonally connected beam from the room below, maybe 36" at the upper ceiling corners on either side of her space. No matter what we do to help support the floor and load, I really appreciate Stuart's advice: be careful to isolate them with a soffit or box to preserve the inner leaf. -mt EDITED: "just ties in diagonal truss beams inside the walls as Stuart suggested" - you are right to clarify me there, it wasn't his suggestion for the diagonal beams - just that any post or beam inside the space should be treated as outer leaf, and separated from the inner leaf appropriately.

It's been a little while since I've updated, but here's some key updates to the latest thinking: - the direction of the build will move towards a large, single room with improved outer leaf and newly constructed inner leaf (MAM design). - glue, screw and seal the existing floor (actually is now just a raw sub-floor); maybe add a layer of mass-loaded vinyl to seal it even further - the existing wall's drywall will be relocated to an improved mass on the outer leaf - acoustically sealed and upgraded insulation - a new inner leaf will be installed - isolated from the floor below and existing ceiling structure (suggestions?); equally sealed and insulated to match the mass of the outer leaf - improved acoustic sealing and insulation on the existing ceiling will be treated as an outer leaf - a new floating ceiling will be hung from the existing ceiling with RISC hangers and hat channel, with an additional layer of drywall - do I need to remove existing ceiling drywall? - inside the inner leaf space, install a leveled and floating floor - 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 On the subject of load/support to solve the the "bouncy" floor - I did get some structural advice that it would be quite easy to install transverse support beams from the space below; diagonally from the walls below, up to the floor joists. Again, below is just a simple drop ceiling with tiles - otherwise the joists are accessible for bolting an array of eight 2x12's diagonally on either side of the room underneath. With some paint finishing, my wife sez that would be not be that disruptive to her art studio below. The engineer sez it's the most simple and cheap solution he could imagine to reduce the bounce and increase load capacity in the middle of the space. There will be more questions I'm sure on moving windows, doors, lighting as we proceed - but the basic MAM outer/inner leaf design seems like it'll be just the fit for this space. Cheers, -mt PS - latest virtual rendering here: http://vimeo.com/127655143

Hi guys - just a quick update on our music studio remake: - the current studio gear is downsized to my office in another part of the house - some of my bigger gear is boxed up and moving to the attic for safe keeping - next up will be some demolition of the current space - the inside wall of the outer leaf And before any real studio construction begins: - it turns out the skylight in that room is not structurally supported, so it's coming out completely :( - need some sistering the roof rafters with plywood and re-roofing (preparing for solar panels on the roof) - and removal of existing subfloor + sistering of floor joists with plywood & replacing the existing failed blocking/bridging My next few areas of research will come around the following areas: - rebuilding the floor...what layers to build there? 1" plywood + mass load vinyl and seal everything? - changing heating from baseboard hot-water heat to in-floor radiant? Tubing? Could it be done? - adding cooling and fresh air system in the ceiling cavity - can I isolate the exchanger and fans up there? 400 sq foot room = 2 vents? Sizing? I've started a Sketch up - that'll come next. Thanks again for the advice and ideas. -mt

- 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? :shock: 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?

:roll: 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 -

Thanks Stuart - as usual, you are absolutely right about every point in your feedback, as you have been on this entire thread. You've pulled some quotes from my original ideas/plans from the beginning of this thread and I can see also...my thoughts/ideas/plans have changed a bit. At first, I really thought I needed a studio that could operate as a commercial studio with 90db isolation around the entire space - that takes massive structural changes...that will never happen. What I mean is, I'll probably not be operating a commercial studio in my house. This is a home project studio that has flexibility in time and use...so the occasional airplane, fire truck siren or car horn would not be disrupting a client that is paying for time on the clock. And, as long as those sounds aren't absolutely intrusive, I don't mind them in the mix. More like funky home-made cooking instead of store-bought sterile, if you follow my analogy.

"How much isolation do you need, in decibels?". Without knowing the answer to that question, you won't be able to get any answers.

The short answer is that I don't know yet. The two thoughts I have are this: - the goal for the isolation would be to significantly reduce typical neighborhood sounds - barking dog, car passing by, lawn mower, anyone talking in the yard next door. The highly intrusive and quite infrequent sounds of aircraft (helicopters mostly) overhead could just mean a missed take or a delay for a few minutes. Nothing major for a personal recording space. Summertime is here, so those noises will be loudest over the next few months. - I don't yet have any existing noise dBA measurements for the space...maybe I could do that next? That would give me an idea of which frequencies are most common and design to abate those frequencies? Could I do this with an existing microphone or should I really get/rent a good SPL meter?

I very much doubt that you'd be able to float [the floor] 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?

- I did have 2 structural engineers come take a look at the space and suggested plywood sistering to increase support for load and replaced blocking/bridging to the floor joists to remove the bounce. That should suffice, if I'm able to avoid a concrete floor for isolation - which is your point, I agree. - thanks for your points on MLV being expensive - it might be best used on walls where the structure can support the weight. - also, I'm still missing an outer leaf on the floor if I just beef up the mass on an existing layer of subfloor. I guess the same for the ceiling. - You mentioned "Why not just put a couple of RSJ's in there" - can you point me to more information about what an RSJ is? what other materials would be useful for increasing mass on the floor? - and the drywall/insulation will be coming down to work on the roof rafters...so how to rebuild the ceiling for MAM? The most common sources of noise come from outside the lateral walls (neighborhood sounds) and ceiling (aircraft overhead) - but my wife's studio below is most often quiet. I appreciate your point about the ceiling also - perhaps improving the mass above and to the sides is more important than the floor?

What ceiling cavity?

There is a 2+ foot space above the ceiling, sloped down to the outer edge of the back of the house. So, like a shed style roof over a flat ceiling. Looking at the pictures in previous posts, it's to the left side of the room above the ceiling. Should be plenty of space to install proper HVAC. I agree, the calculations you describe are now added to my to-do list. :) UPDATE: on the point of "what is an RSJ?" ...let me google that for ya: https://en.wikipedia.org/wiki/I-beam

This is a home project studio that has flexibility in time and use...so the occasional airplane, fire truck siren or car horn would not be disrupting a client that is paying for time on the clock. And, as long as those sounds aren't absolutely intrusive, I don't mind them in the mix.

Ahhh! Ok, then it isn't as extreme as it sounded at first.

- I don't yet have any existing noise dBA measurements for the space...maybe I could do that next? That would give me an idea of which frequencies are most common and design to abate those frequencies? Could I do this with an existing microphone or should I really get/rent a good SPL meter?

you can't do it with a mic, as you'd need some way of calibrating that, and the normal way to calibrate a mic is with... a sound level meter! A decent one (Extech, Galaxy, etc.) will cost you around US$ 100 or so. Do not get one of the cheap Chinese junk toys that go for around US$ 30 or so. Garbage.

- I did have 2 structural engineers come take a look at the space and suggested plywood sistering to increase support for load and replaced blocking/bridging to the floor joists to remove the bounce. That should suffice

I very much doubt that would provide the type of support you need. Your engineers probbaly did not understand the amount of mass you need to float a floor... Not sure if you saw this: viewtopic.php?f=2&t=8173

- thanks for your points on MLV being expensive - it might be best used on walls where the structure can support the weight.

I think you missed the point: It is EXPENSIVE. Several times the cost of plain old drywall. If you need more mass on your walls, you'd be far better off with an extra layer of drywall,and it would be much cheaper too. Forget MLV. I only ever use it for a few specific things, but almost never as mass in walls.

I appreciate your point about the ceiling also - perhaps improving the mass above and to the sides is more important than the floor?

The mass (=surface density) needs to be consistent all around. It does not make much sense to have very high mass on only one side, as sound will simply flank around that using the other sides.

UPDATE: on the point of "what is an RSJ?" ...let me google that for ya

Yup! :thu: - Stuart -

How much isolation do you need, in decibels? Without knowing the answer to that question, you won't be able to get any answers

Backing up from all my ideas, I'm taking Stuart's advice and trying to answer this question specifically. First, I live in a fairly quiet neighborhood at this point in time. There's little chance for future changes in the noise sources around the neighborhood aside from temporary construction, etc. Although they are infrequent and unplanned, the worst and most intrusive sounds in the studio space are: - a local firehouse siren - jet planes overhead - low-flying hospital helicopter overhead - loud vehicles passing on cross street 1/2 block away - lawn mower/blower next door - wife's stereo in studio space below Is my next move to get dB measurement on each of those noises from the current construction of the space? This would give a baseline. That current construction consist of: - exterior walls are 1/2" drywall on wood studs, standard insulation to exterior sheathing and siding. - interior walls are 1/2" drywall on each side of wood studs, standard insulation. - floor is 3/8" plywood with gaps, minimal insulation and unsealed drop ceiling below. - ceiling is 1/2" drywall on wood joists with standard insulation, with upper layer of roof sheathing and roofing materials. Then my next move will be to attempt a dB measurement outside/inside each of those surfaces to determine existing STC. Considering it is standard construction, each surface is probably an STC of 30 or less. When there is noise, I can hear it in a recording. If I could cut that noise level by 50% it would be a great improvement. So, perhaps my goal is to get to an STC of 50 or greater? And what about frequencies above/beyond standard STC? I do expect have drums and bass in the low-end ranges.

Great! Sounds like you are moving on the right track now.

each surface is probably an STC of 30 or less. When there is noise, I can hear it in a recording. If I could cut that noise level by 50% it would be a great improvement.

To get a subjective 50% drop in levels, you'd need an extra 10 dB of isolation. That's not very much, and not to hard to do, but I'd say that you need more than that.

So, perhaps my goal is to get to an STC of 50 or greater?

That would be better, and is a reasonable goal. But not measured in STC! STC is a rating system that is of no use at all for studios, since it does not take into account the bottom two and a half octaves of the musical spectrum, nor does it take into account the top two and a half octaves. It only considers the middle part: voice range, roughly. Don't use STC numbers to judge isolation.

And what about frequencies above/beyond standard STC? I do expect have drums and bass in the low-end ranges.

Yup. You need to be thinking in terms of "decibels of transmission loss". 50 dB TL is a very decent level of isolation for a home studio, and is also achievable. - Stuart -

Sorry for the delay, it's been a busy few years in other work, but I'm finally returning to our work on the home studio. I've started some initial demolition just to see what the materials are behind the walls and floor. I found this not-wood looking material used on both the exterior walls (e.g. the outer leaf). http://drive.google.com/uc?export=download&id=1c3WCvMkOVIcOtQ89GIxdUV9jkPL7b3dn http://drive.google.com/uc?export=download&id=106RjL2ba6-hYAafuYfnqZuC2ldoNPkv4 It's not wood. Is it old gypsum from 1978? Some kind of fiber board? Masonite? Homasote? And if I wanted to add more layers/mass to that exterior wall (outer leaf) would I just use Green Glue and add more of the same material? -mt PS - finally took me time to get the images posted nicely...sorry