upper floor load limit

How thick should my walls be, should I float my floors (and if so, how), why is two leaf mass-air-mass design important, etc.

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Soundman2020
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Re: upper floor load limit

Post by Soundman2020 »

back then I was instructed to build walls featuring plaster/caneite/plaster on both sides of both walls separated by a 50mm gap. Imagine my surprise to find , like Rumplestiltskin awaking after 20 years, how much the world has changed regarding Studio Acoustics!
There certainly have been many advances in the science of acoustics over the years. Studio design has advanced along the same path. Back then, LEDE was still in vogue somewhat, but has long since been abandoned, replaced by more modern extensions, such as RFZ, NER, and suchlike. New techniques have been developed, speaker technology has advanced by leaps and bounds, DAWs have replaced monster consoles and racks of gear (to a certain extent), multi-track tape decks are now museum pieces, replaced by hard disks, acoustic measurement technology is way ahead of where it was, and the Internet has changed everything. It's a different world.

So it's not surprising that you are a little lost with your new build. There are just a whole bunch of different ways of doing things now, and the "bar is set higher". Rooms that were considered fantastic 20 years ago would now be considered mediocre, acoustically. Small project studios today can do some things (but not all!) that only large high-end facilities could do 20 years ago.

Trying to stay on the leading edge of all of that is a challenge! You'd be surprised how much time I spend researching new stuff every week, to see if I can make use of it in any way. The old dogs DO need to learn the new tricks, if they still want to run with the pack and have a full bowl at the end of the day!
Seems like I did so many things "wrong" last time for way much more cost and time than what was required, that I thought I should be more careful this time
They were possibly not "wrong" at the time, but there's better ways of doing them now. And likely there'll be even better still ways of doing them in another 20 years....
One thing that is truly remarkable about this new online age of disseminating ideas and advice is that there are incredibly well informed and generous people like yourself happy to give away some of what they know on Forums such as these, for free! I think I get it (although not really sure), I guess it's about building up credibility and trust in a public forum which engenders relationships and contacts that lead to paid gigs, or something.
Actually, for me it started out more along the lines of just wanting to help people avoid the pitfalls, common errors, and snake-oil vendors, so they could build nice places without wasting money or getting bogged down. Then people started contacting me off-line, offering to pay for me to design stuff for them (and John very kindly even sent me a few of his potential clients, when he was overbooked). It sort of grew from there. Yes, being involved in the forum does bring about the benefit of making a name and reputation, and helping to put bread on the table, but to be very honest, I still love just helping out! I hate it when I see people being "sucked in" by the acoustic nonsense spewed out by so many places on the web, or suckered into buying hugely expensive products that they do not need, and which would not do what the wanted anyway. I love pointing people at better ways of doing things. That's a really big part of why I'm here: because helping people do it right is sort of a passion. It's a bonus for me when they want to pay me for doing it! But of course, there's only one of me, so I do need to split my time between paying customers, and helping out forum members who prefer to not pay, for whatever reason. As long as it's a reasonable reason! :) As you already gathered, I'm not much into handing out freebies to people who could afford to pay, and probably need to pay, but just don't want to....
Let's see, we have Gervais, Alton Everest and Phillip Newell, which one to buy,
All of the above! Then compare them, do the math, do the research, and see why 1 and 2 are preferable to 3 in some senses...
oh, hang on, they don't really cover what I might want to do, or if they do, they don't exactly agree.... there's so many differing opinions out there that one needs to be an expert to sort the wheat from the chaff - but even there, what is wheat and what is chaff will depend on perspective, one man's ceiling is anther man's floor, and all that
There's a lot of truth in that, but what is often mistaken for differing opinions, is often not differing at all! It's not that one guy is wrong and the other right: They can both be right, in their own context. Basically, there are different design concepts. Different ways of getting to the same result, provided that you do it all, not just parts. If one guy tells you that the front wall must be soft and the back hard, then he's likely a LEDE guy. If another guy tells you that the back wall must be soft and the front hard, he's probably a CID or RFZ guy. If a third guy says they are both wrong, and that rooms should be as soft as possible all around, but balanced with some hard surfaces, then he is probably more used to doing multi-channel rooms, while the other two were talking about stereo. If someone tells you that rooms should be purely rectangular to maximize volume and make modal issues easy to predict, he's probably used to doing small rooms, but the guy who tells you that angling the walls and ceiling is great, and bass trapping isn't as important as diffusion, is probably a guy who mostly works on large rooms. The guy who tells you that the console should go towards the back of the room is probably doing very large rooms for cine work, and they guy who says that the console must always go up front is likely doing home studios, or project studios. The guy who rejects diffusion and wants all absorption is a small room guy, while the guy who says the opposite is a large room guy. And none of them is wrong! They are all correct, within their design concept. But if you try to apply original LEDE concepts to an RFZ room, or large-room treatment concepts to a small room, you are guaranteed to end up with disaster. They are incompatible.

To most people, that's confusing! They all seem to be giving conflicting advice, but in reality they are not. They are talking about specific cases. Just as a surgeon would prefer to cut you open and pull out the bad parts, while a pharmacists would prefer to hit you with a barrage of drugs, and a shrink would just want you to talk, so too there are different approaches to studio design.

Having said that, there's still a lot of garbage out there, that does not fit into any valid category of acoustics! There's an awful lot of snake-oil out there, waiting to be sold....
I wish it was as easy as paying one man to "project manage" the whole thing, but It's not, is it?
You could ask some of my customers. And some of John's. And some of Andre's. And some of Glenn's.... :) They don't seem to have run into that issue!
How would I know if it's possible to project manage from another country without being able to get a feel for the subtleties of a space?
Take a look here, and give Rod a call: http://www.johnlsayers.com/phpBB2/viewt ... =2&t=20471 He'd be happy to chat to you, I'm sure. Even though I have never been to his place, and never met him in person, and never even spoken to him on the phone, his place seems to have worked out OK. Check out his website, too: he asked me to write up a brief "The Making Of" story, regarding how it all worked out.

John can likely put you in touch with a couple of his customers too, if you want.

It might interest you to know that for the vast majority of studios I design, I never get to see them, or visit them, or meet the owners. Pretty much all of what I do is over the internet, from first contact through the entire design process, as well as the construction supervision, the system calibration, treatment, and final tuning. That is entirely feasible today. All of that can be done over the Internet, very simply and easily. I'm pretty sure that John works the same way. 20 years ago that was not possible, but today, it's the way things are done.
How do I know if a local guy who can visit the space often, has enough experience in my kind of build to get it right?
Good point! :)
How do I know if it's possible to reach a compromise b/n what "works" and what feels good to sit in the middle of each day?
There does not have to be a conflict between those two. What works should automatically be a great place to sit in each day. I'm a firm believer in "form follows function", meaning that the studio should first and foremost be designed for optimum acoustics, then the aesthetic and artistic side can be put into place around that, to make it look nice and feel nice, as well as sounding nice. On the other hand, if you try to design the place so that it looks nice as first priority, then try to shoe-horn in the acoustics without changing the looks, you'll never get good acoustics. It might win awards for beautiful architecture, but it wont be a studio, and won't attract clients who need quality sound.

Here too things have changed over the last 20 years. What used to pass for "acceptable" acoustics is now junk. What used to be great is now merely "OK". What used to be spectacular is now just "pretty good". So your customers who are looking for the latest and greatest, expecting that a brand new studio in a city such as Melbourne will sound leading-edge, are going to be rather disappointed if it only sounds like a place built 20 years ago. Back then, there were people with reputations who built places that other people liked. Today there are internationally recognized technical specifications that a room needs to met in order to be considered great, and those specs can be checked and measured reasonably well by a guy with an app on his cell phone! You can't fool people the way you once could. Today, if you want to compete in the high end, then it takes more than the impressive logo on your console or speakers, or the range of big-dollar mics in your mic cabinet, or the range of sticks and platters on your drum inventory. The studio itself also has to meet the specs, or at least get close.

So yes, things have changed: studios are built differently today, and to higher standards. If you want yours to compete and beat the competition, yours has to be up there, at the same level as the best of them. Not 20 years behind.
As for your question- Am I looking for a professional designer, or do I want to design the space myself? - I think the answer is both! I'd love to have something designed around my idiosyncratic needs... ... I'm a musician, producer, and studio manager - in that order. One thing I am not, and that is an acoustic engineer, nor am I an architect, electrician or HVAC consultant.
OK, down-to-earth, up-front, in-your-face, no-punches-pulled realism: It will take you roughly three to six months to get from where you are right now, to the point where you have a good enough grasp of acoustics to be able to design your place yourself. It will take you another couple of months to learn the techniques, construction materials, and methods for actually designing the place (including structural, HVAC, acoustic, electrical, and architectural), as well as learning the design software, then another three to six months to actually design it in full detail, and optimize the design. Then, and only then, would you be ready to apply for your permits, do your BoM, figure out your final budget, and actually pick up a hammer for the first time. Call it a year, to be on the safe side. That's a realistic estimate of what it takes for a typical person with some knowledge but nothing specialized, to get to the right point. That might see like a lot, perhaps exaggerated even, but it really isn't. As with learning any new skill, it takes about 2,000 hours of research and study and practice to become reasonably proficient, and about 10,000 hours to be come "skillful". Some people come along with the idea that it isn't that hard, and can be done on a few weeks, but that's sort of like me telling you: "I'd like to learn the guitar: I'm sure I'll able to play like Peter Framptom by the end of the month". Or saying "I just bought my first drum kit: I reckon by June I can keep up with Phil Collins, and do concerts like he does". :) I'm sure you get the point. You can't get from nothing to expert in a few weeks.

Now, if that's the way you want to go, then excellent! You can bet I'll be happy to help you along the way. No problem. I'd just insist that you don't pick up a hammer until you have the completed final design, in April of 2018.... :) If you can leave your place on hold for that long, then go for it! Many forum members have done just that, and then built excellent studios. You'll find their stories all over the forum: but check the "start date" and "end date" of their threads, to see if I'm telling it like it is, or not...
While it's ok throw up a bunch of equations and say " the numbers don't lie"- it must certainly seem an insult to your profession to think that a musician could down his own tools for a few months and learn to be a studio designer by receiving guidance on a single internet forum.
Not at all! As I said, many forum members do that! But not in a couple of months. I'm sure you can, if you want to.... but "a few months" is not realistic. It will take you about as long as it takes a neophyte musician to go from picking up a guitar for the first time, to playing flawlessly in concert doing a Peter Frampton cover. How long does that take, realistically? As a musician, you know it can't be done, except maybe by the most talented and dedicated. For most people, it would be a year or so.

Just like it looks really simple to stand on stage and pluck a few strings with your fingers, while stomping on pedals with your feet, but turns out to be quite different when you actually have to do it, so to it looks simple to draw a few lines on a bit of paper and call it a "studio", but it's actaull not that easy once you try. I'm sure you'll find any number of forum members who can vouch for that! Or look at the statistics here: we have over 21,000 members on the forum, all of whom came here with the desire to design and build their own studios, but only a few hundred who actually went though with it to completion. There's a saying in Spanish: "Otra cosa con guitarra", which translates roughly as "It's another thing when you actually have the guitar", meaning that it's one thing to listen to guitar music and comment on it, and quite another to actually pick one up and play. It's one thing to arm-chair quarterback a football game on TV, and quite another to actually be out there on the field. It's one thing to manage a studio, and quite another to design one... :)

There's also the issue of usage: Do you really want to spend a year learning a skill that you might only use once or twice in your life? Maybe someone might have a dream to learn the guitar well enough to just once stand on stage and do a concert of Peter Frampton's greatest hits, then give it up forever and go back to what he normally does.... But personally, I'm not sure I see the point in that!

Don't get me wrong! I'm not saying you should not try! By all means, if you have the time and the inclination, then go ahead! I'm just giving you a real-world point of reference about what you should expect in your voyage.
But I will try to do as you suggest, only that, if I can't deal with it, could I engage your service on a professional level?
Of course! But do try with John first. It's his forum, not mine. I'm just here by invitation. I don't work for John, and I certainly don't want to be first on the list of people that forum members contact for design services! John just allows me to run this forum for him (even though I've never met him either!), but I definitely should not be your first choice for designing your place. He has years more experience than I do, and indeed I learned a huge amount about studio design from him, so please don't put me at the top of your list. Also, I'm rather snowed under right now with several projects in various parts of the world, so I would not be able to take on your project immediately anyway: Contact John first. If he is also too busy to be able to take on your project, and you don't mind waiting a bit for me, then we can talk.
Thanks again for your (free) help. FWIW, it's the best I've had, by far!...
:oops: :oops: :oops: Thanks for the compliment! :oops:


- Stuart -
princeplanet
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Re: upper floor load limit

Post by princeplanet »

Been reading some of John's blogs, but they seem very outdated. TBH, I think from what I've read, that your perspective on things is closer to my needs that perhaps John's, even though you obviously learned heavily from him...

I can wait, I can'd commence building for 2 months anyway, which gives me some time to get a design happening, right? 8) Still lots of solutions to consider to my main problem - how to get 70dB T/L for a drum kit with an office on the other side of the Live Room?

I think I can calculate the resonant frequency for a double leaf floor or wall system, but I can't find a calculator for low frequency Transmission Loss through similar systems.

For example, If I get a floor or wall down to 14.1 Hz - with the lowest "working" frequency at 20 hz - then that tells me nothing about how much T/L to expect at , say, 40Hz. What I'd like to know is what kind of a wall will provide 70 dB isolation for a drum kit at 115 dB, assuming this will be enough to be of little disturbance to someone on the other side of said wall. How much mass on each wall and how deep an air gap (insulation filled)?

Given that a drummer will be right next to an adjoining office, If it was too much expense, weight or space to get the whole room isolated, then is it possible to construct a small 6m2 drum booth away from the wall (but still within this room) with a concrete floating floor and massive walls and ceiling to get the required 70 db TL down to say 40hz? If I also "soundproofed" the rest of the room, and had the massive drum iso booth 2 metres away from the adjoining office wall, would that work? If so, then how massive and how deep should the cavity be in the drum booth? Should the drum booth be a single or double leaf? Either way, I'd have either a triple of quadruple leaf system (the rest of the room would still be box in a box). But given the distance between the 2 wall systems, surely this is OK?

I think I understand that it's pointless re decoupling the drum booth floor from the already decoupled room around it, but surely it helps to have a thicker slab of concrete below the drum booth than for the rest of the room? And thicker ceiling?

A lot of questions, I know, but you seem to like details, so......
Soundman2020
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Re: upper floor load limit

Post by Soundman2020 »

I think I can calculate the resonant frequency for a double leaf floor or wall system, but I can't find a calculator for low frequency Transmission Loss through similar systems.
I did give you the equations in one of my posts on page 2 of this thread, here:

http://www.johnlsayers.com/phpBB2/viewt ... 0&start=28

It's not just a calculator that you need: it's a bit more complex than that! You need all of those equations: Mass Law, MSM resonance, and the others. There are several regions of the audio spectrum that have different isolation properties, depending on how the wall is built, which is why you need those equations: so you can calculate isolation in each of the regions. There's also the issue of the coincidence dip, which usually isn't a problem for studios that only need low to medium isolation. But for studios that need high isolation it does become an issue, so you need to take it into account. But to understand how to do that, you'll first need to do some research on bending waves, and non-normal incidence of sound waves, and the acoustic impedance change at wall boundaries.
For example, If I get a floor or wall down to 14.1 Hz - with the lowest "working" frequency at 20 hz - then that tells me nothing about how much T/L to expect at , say, 40Hz.
See above! :) That's where the other equations come in. You calculate the mass law TL for each leaf, and f0, then you use the equations to determine isolation for each region.
What I'd like to know is what kind of a wall will provide 70 dB isolation for a drum kit at 115 dB,
A big one? :) Seriously, the answers are all in those equations. You might want to spend some time creating a spreadsheet that will do it for you and graph the predicted results.

That's fine for walls, but when it comes to floors, you also have to take into account the "other" spring: Even though air is still your primary spring for floated floors, you also have the secondary spring(s) that run in parallel with that: the isolation mounts on which your slab rests. Since they are in parallel with the air spring, and since this is basically resistance we are talking about, the resilience of the isolation mounts reduces the total isolation: it weakens the effect of the air spring, in other words. So you can't get an accurate picture of how your floor will isolate from considering only the air in the cavity: you need to consider the reduction due to the physical springs.

provide 70 dB isolation for a drum kit at 115 dB, assuming this will be enough to be of little disturbance to someone on the other side of said wall.
That's where you need the Fletcher-Munson curves: You need to fit those to the results of your calculated TL and see if the final outcome will be good enough that your drums are inaudible in the office next door. 115-70=45, so you'll be looking at the 40 and 50 phon curves, and the ones adjacent to those, then comparing that to the the typical sound levels in the office nest to you, and seeing how that looks.
Given that a drummer will be right next to an adjoining office,
Not with my layout he wont! :)
If it was too much expense, weight or space to get the whole room isolated, then is it possible to construct a small 6m2 drum booth
It's possible, yes, but you and I both know that a 6m2 drum booth is not a drum booth at all! It's a closet. Drums recorded in there would sound pretty bad. Drums need air, space, ambiance. In fact, with a decent sized drum kit having lots of pieces, you would not even be able to fit it into 6m2, along with the mics and the drummer... So it is technically feasible to do that, but in reality it's not practical. You would not have many return customers in your drum booth... only first timers who you managed to fool into coming... :)
A lot of questions, I know, but you seem to like details, so......
:)


- Stuart -
princeplanet
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Re: upper floor load limit

Post by princeplanet »

OK, will check that equation again, cheers. As for the fortified, lead encased, nuke-proof, drum bunker from hell,... let's say we make it 10 m2 ;) PZM's on the walls, and PZM's on the outside of the window. Not ideal, but I have done this in the past in small rooms and it was surprisingly good!

Realistically, according to the maths, I should be able to get away with a fairly light weight booth if it created enough distance between the drums and the office wall, right? Been looking into acoustic, glass panelled folding doors that could possibly open all the way back out to the Live Room walls for ordinary room use, and just use the folding walls to enclose the drum booth on the (hopefully) rare occasions when I really need to record something loud during business hours. Of course, even if the adjacent office was happy in this instance, doesn't mean the poor folks beneath me would be!... That's why the idea came to me about thickening the floor for the drum booth, or, if I wanted the floor level to be even throughout the entire live room (and I do), then maybe I could have steel plate for part of the drum room floor? Steel is actually not that expensive, why don't we hear about it being used for studio isolation so much?
princeplanet
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Re: upper floor load limit

Post by princeplanet »

Hi Stuart, I'm still gathering information and ideas, like the idea of using plate steel for the floor, and while I'm thinking outside the box, what about concrete pavers as opposed to poured concrete? The quote for formwork, laying, pumping and for the concrete itself turns out to be at least twice the price of the equivalent amount of square metres for 2 layers of 30 mm thick concrete pavers. Plus, I'd need to pay a 50% after hours surcharge for the concreters to work outside business hours, which would be necessary owing to the fact that I can't run a line pump up the fire stairs during business hours. So yeah, that's an idea waiting to be shot down, so shoot away! ;)

Slowly gaining the required understanding of basics, but still running into walls- speaking of which, floating walls vs walls on floating floors.... Why can't the walls float on rubber or spring isolators the same way the floor will be? Why wouldn't it perform as well? I understand that resting on the floor the walls and perhaps ceiling, the added weight to the floor and subsequent spring deflection would be such that any varying live load would do little to move the springs out of their "Goldilocks" zone. But if the floating structure (steel, concrete or pavers) has a surface density of say 150kg/m2, then surely that is heavy enough to avoid wide differentials of live loading?

You must admit there are advantages in not placing walls on floating floors, like: easier to calculate, no "crowning" effect, less direct loading on the underlying structure (remembering our limitations), easier to construct etc, so why does it seem from my reading that floating the walls separately is not as commonly done? I should remind you that I'm thinking to have 3 x 15mm CFC sheet walls (75kg/m2).

The other new idea is to have drum and amp booths on the window side of the live area, but that they be composed of heavy duty acoustic folding walls that can be moved either into a stack, or against the wall, either way opening out the live area where appropriate or desirable to do so. These walls are top rollers with no bottom rail, have glass panels, and have a heavy duty drop seal when in place. Even if these walls have an STC (or RW?) in the early 30's, the fact that the nearest neighbouring wall is metres away should ensure a significant TL by virtue of the principle that light weight leaves need very large gaps to be effective. On top of this, I'm also contemplating having a larger air gap of say 250mm between the 2 leaves of the LR, while only 150 for the CR. In fact I'm considering having less mass for walls , ceiling and even floor for the CR.

I know it sounds like I really need to be asking John to take the reins, and I may still end up going that route, but I'm enjoying investigating/exhausting all these "outta the box" ideas first. Certainly don't wanna die wondering..... :?
Soundman2020
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Re: upper floor load limit

Post by Soundman2020 »

I'm a little late on the reply, but I only just came across your thread again... :oops:
what about concrete pavers as opposed to poured concrete?
How would you attach them to each other? Mortar? What if it cracks? Is it the same density as the concrete? How would you seal that? Is that allowed by code? Would your inspector / authorities approve that as the base surface? Do you have any acoustic data on how that would work in practice? Has it ever been done before?
floating walls vs walls on floating floors.... Why can't the walls float on rubber or spring isolators the same way the floor will be?
How would you achieve a seal between the walls and the floor, while still allowing them to move independently and yet also attaining the very high mass (density) that you need? What materials would you use for that? Would it be able to handle the stresses and strains from thousands of kg of mass moving in different directions at the same time, at different frequencies? Has it been tested for that?
You must admit there are advantages in not placing walls on floating floors,
Ummmm.... I don't think I'll be admitting that.... :)
easier to calculate,
Really? So you'd prefer to do three sets of calculations, one for the line loading of the walls, one for the area loading of the floor, and one for the properties of the resilient layer that bonds them together yet allows them to move independently while not transferring any load, stress, or tensions between them in either direction, while also retaining the air-tight seal, as well as providing the necessary surface density? I'm not sure that I'd agree with you that this is "easier to calculate".... :)
no "crowning" effect,
I'm not sure what you mean by that term. Please explain.
less direct loading on the underlying structure
:shock: :?: :!: Ummm... How do you figure that??? If the walls hypothetically weigh 3000 kg, and the floor hypothetically weighs 3000 kg, no matter which way you look at it, you have 6000 kg there! If your floor area is hypothetically 60m2, then you have a load of 100 kg/m2, no matter how you look at it. The load is the same. It's the way you SPREAD the load that matters, and from that point of view, the load is spread better if the walls rest on the slab, than if you do it separately. If your walls are NOT on the slab, then you have a line load : all that mass is resting in a very thin line on the floor, so there's a very high load along that line. But if the walls are resting on the floating slab, then the load is spread out over a much wider area (assuming that your isolation springs are laid out correctly....
easier to construct etc,
Really? :) SO you think that attempting to float TWO massive assemblies is easier than trying to float one? Especially considering that they would just be a few mm separate from each other, and must be built independently.... I'm not sure I'd agree that this is "easier"...
so why does it seem from my reading that floating the walls separately is not as commonly done?
:) See above...
I should remind you that I'm thinking to have 3 x 15mm CFC sheet walls (75kg/m2)
I have a better idea than that... :) In less thickness you'd get the same mass (or more), plus the advantages of non-rigid mass... :)
The other new idea is to have drum and amp booths on the window side of the live area, but that they be composed of heavy duty acoustic folding walls that can be moved either into a stack, or against the wall,
It seems like you really are not thinking this through! :) Movable walls that weight thousands of kg? Ummm.... How would you move them? Where will you have the hydraulic pumps and/or electric motors to do that? What type of mechanism would you build that would allow you to move such massive objects? Are you considering that when they are "folded" against the other walls, there will be a huge line load at that point, probably beyond the ability of the building structure to handle? How would you account for that in your isolators for your floating slab? The load would be doubling and halving along that edge as you open and close the "walls".... How would you achieve an air-tight seal between the sections of the wall, along the "folds"? What would you do with the treatment that is on the walls of the booths and the live room, as you move the walls around? How would you account for that in the tuning of the room?
these walls have an STC (or RW?) in the early 30's
So they are no better than typical house walls? Yet you need to go to all that expense and complexity, just to get lousy isolation? Ummm....
the fact that the nearest neighbouring wall is metres away should ensure a significant TL
Ummm.... I'm not sure I'd agree with your line of thinking here...
I'm also contemplating having a larger air gap of say 250mm between the 2 leaves of the LR,
:shock: Why? You have a very small area to start with, and you want to sacrifice half a meter of length and width? I'm not following your line of reasoning at all here. Sorry...
In fact I'm considering having less mass for walls , ceiling and even floor for the CR.
... implying that you don't actually expect to get high isolation at all...

OK, reality check time: You are trying to do what lots of people in your situation have tried to do: Attempt to find a way around the laws of physics, in the hope that there's a magical set of materials that will get you more isolation than it is physically possible to have. Unfortunately, you cannot "wish away" the laws of physics; they will still apply to your studio, just as they apply everywhere else in the known universe.

The most basic problem here is that you are attempting to build a studio that needs very high isolation, on an upper floor. The laws of physics REQUIRE that in order to get the level of isolation that you need (TL), you need a lot of mass. Period. There's no way around that. You have a LIMITATION on the amount of mass that you can use, due to the structure of the building. There's no way around that without modifying the existing structure. So that requirement is running head-on, smack-bang into the middle of that limitation, and there just isn't any way around that.

You cannot get high isolation without high mass. Period.

Yes, you can increase the air gap to improve isolation, but look at the math! Each time you double the air gap, you get an increase of maybe 3 dB. But each time you double the mass, you get an increase of maybe 12 dB!! It's a no brainer. You have to give up huge amounts of space to get decent increase in gap isolation, as compared to mass increase. A tiny studio with a low ceiling and raised floor will have lousy acoustics, and there's no way around that either! Another law of physics. You cannot make a small room sound like a large one (I could go into all the reasons why that isn't possible, but I'm assuming you already know this is true: you cannot make the broom closet sound like an aircraft hanger, no matter what you do.)

So, the ONLY answer here, as with all studios, is compromise. Something has to give. You cannot get where you want to go, so either you have to make a plan to go somewhere else (a different studio location, different building), or you have to accept where you CAN go with this one, which isn't where you WANT to go.

OK, so how would I go about this, if it were my studio? First, I'd sit down with the structural engineer and get a detailed analysis, in writing, of the TOTAL load that I can place on that floor, and also of three or four ways I could distribute that as a set of POINT LOADS on a regular grid without overloading the floor. I would then total up the weight of all of my gear, furniture, instruments, decorations, etc., and the maximum load due to occupancy, PLUS the load of the existing partition walls that are already there, and SUBTRACT that subtotal from my total available load, to come up with a figure that is the absolute maximum possible weight that I can have for all of my walls, floor, ceiling, windows, doors, HVAC system, electrical system, etc. Then I would work backwards from there to see what the maximum possible surface density is that I could conceivably have for my outer-leaf and inner-leaf. With that number in hand, I'd then look at realistic air cavity depths, and see what type of isolation I can expect, and what frequencies I can expect it at. Then, and only then, would I make the decision about whether or not that is acceptable. If it turns out that it is not acceptable, I'd pick up the phone and call the real estate agent to find me another location for my studio.

That's what I would do. I would not try to invent untested combinations of esoteric materials that nobody every thought of before, in the hope that they would bypass the laws of physics. I would just look at the reality, do some math, and come up with an answer. If the answer is "ZZ dB total, with YY dB at ZZ Hz", and that's good for my needs, then I'd go ahead and build it. If that combination is NOT good for my needs, then I'd cut my losses and go elsewhere.

It's that simple. I'm guessing that you were hoping I'd have a different answer for you, but unfortunately I don't. All I have is the laws of physics, the limitations imposed by your building, math, and reality.
but I'm enjoying investigating/exhausting all these "outta the box" ideas first.
Cool! Have fun with that, by all means, but I'm seriously doubting that your answers will be any different than those discovered by all who preceded you down the same path... :) Eventually, you'll have to get back "into the box".... :)



- Stuart -
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