I "did" read all of the links and your posting!
... But it seems you still missed the
forum rules (click here).
"four-leaf system"...Yes, as I said, I planned on building entirely new rooms within the completed room/2nd floor photos I showed you...
... and as I mentioned, that would be a really, really bad idea. Or a good idea for your local building supply store, since you'll be making them much richer than they need to be! But a bad idea for your pocket, and a bad idea if you want decent isolation. Here's why, in very simple, easy to understand pictures:
2-leaf-3-leaf-classic-walls-diagram-MSM-walls.gif
What you have right now is either the first or the second image from the left. What you are planning to do is the third image from the left, marked "STC-40". That's pretty lousy isolation for a studio. What you SHOULD be doing is the one on the far right, marked "STC-63". It has exactly the same amount of construction materials in it, yet it blocks over one hundred times more sound. Yes, very literally one hundred times. There's a difference or more than 20 points in there, and each time you go up by ten points, you are blocking ten times more sound. Ten times ten = one hundred. So the choice is yours: you can build it the way I'm telling you to, or you can build it your way and get only 1/100th the isolation.
I have NO idea what a "leaf" is.
This might seem like a really harsh, insulting statement, but it is not meant to be....: it is just the plain truth: If you have no idea what a leaf is, then you have no business designing or building a studio. You just don't, sorry. No offense, and no insult. This is the same as if somebody told you they were going to drive your car, but then said 'I have NO idea what a "brake" is.'. They have no business driving your car, because what they said tells you that they don't have a clue, and will need to take a course in driving before they will be able to do that. That person might be a real great guy, your best buddy in the world, but if he says that to you, there's no way you'd say that he is prepared to drive a car.
Ditto here: you don't know what a leaf is, so therefore you are not ready to design a studio. You are going to need to do a lot of reading and understanding to get to the point where you can understand what a leaf is, so you can then understand why a two-leaf wall is the only intelligent choice for a studio, and why a three-leaf or four-leaf wall is a really bad idea.
I would recommend that you start by studying two books: "Master Handbook of Acoustics" by F. Alton Everest (that's sort of the Bible for acoustics), and "Home Recording Studio: Build it Like the Pros", by Rod Gervais. The first one will give you the basics of acoustic theory in simple terms, without going too heavily into the math, and the second one will give you the basics of how to design and build a studio successfully. More simply: the first one will teach you what a leaf is, the second one will teach you how to build one correctly.
Thre would be an air-gap between the current walls and the new walls
No. There would be THREE air gaps: one inside the existing wall, one inside the new wall, and one between them. That setup will have four leaves and three air gaps. Each of those is a resonant system. It is tuned to a specific resonant frequency. At that specific frequency and for one octave on each side, the wall does not isolate at all. Even worse, it actually
amplifies the sound as it goes through, making it LOUDER on the other side.
Here's a graph that explains it in simple terms:
MSM-AMPLIFICATION-graph---GOOD!!!Ifigtw-V2o.gif
The yellow area on the right is where you have isolation. The horizontal axis is frequency, so towards the left side of the graph is lower frequencies, and towards the right side is higher frequencies. Everything below the dashed horizontal line is isolation. On the line itself is neither isolation nor amplification. Above the line is amplification. The blue part shows how much isolation you get at the frequency where the wall resonates: As you can see, not only do you not get any isolation, but rather the wall actually
amplifies the sound ten time over! It is way louder at resonance.
If you do not design your wall correctly, it will have a "blue area" that is well within the normal music spectrum. Whenever any instrument plays a note in the blue area, it will be amplified by the resonant wall. The wall will only isolate notes that are in the yellow area.
The same applies to floors and ceilings: they are ALL resonant systems. Even if you don't design them to be resonant, they automatically will be. Always.
So when you design them, you have to do so such that all musical notes are in the yellow area: You have to "tune" the wall so that the blue area is at a frequency that is much lower than the music spectrum. In technical terms, you must tune your wall such that the MSM resonant frequency is at least one octave lower than the lowest frequency that you need to isolate. So if you say that you will be playing six-string bass guitar in there, the lowest frequency is around 35 Hz, so you need to tune your wall to about 17 Hz or lower. If you don't, it won't isolate, and the bass will be screaming out across the neighborhood, in all its glory...
So far so good. Not difficult to understand. But here's the thing: the most efficient, least expensive way of building a wall that has a resonant frequency down low enough, is when you have only two leaves in the wall. Two leaves and one air gap. That's the way to get the lowest possible resonant frequency for the least cost and highest efficiency. If you add another leaf inside that wall, then the resonant frequency goes UP. Because you now have two air cavities, and two resonant frequencies, but they will BOTH be higher than what the resonant frequency would have been for an identical wall with only two leaves. And if you add a fourth leaf, the overall frequency goes up yet again! You now have
three resonant cavities, each with its own frequency, and the combined resonance of all of them is even higher, yet again, than for the three-leaf or the two-leaf. The more leaves you add, the worse it gets.
This is not intuitive: most people think like you do: that if one leaf is bad for isolating, and two leaves is good, then three leaves must be better still, and four leaves must be fantastic. And they are very, very wrong: When they they build a four leaf wall, they cannot understand why it is so bad at isolating low frequencies after they went to so much trouble and expense....
A leaf is simply a massive surface on your wall with an air gap next to it, and another leaf after that. A standard house wall is a two-leaf wall: it has drywall on one side, an air cavity between the studs with insulation in it, then drywall on the other side. It is lousy at isolating because it is a COUPLED two leaf system, where sound is transmitted from one side to the other through the studs, but it is still a two leaf wall, and it does have a resonant frequency. It is the second example in that picture I posted above. If you build another such wall next to it, as you are proposing, you get the situation in the third image: and you get a measly increase of just four points, from STC-36 to STC-40. Hardly even noticeable. If you build that system that you are proposing, you will be scratching your head and swearing and saying "How in hell can it be that I just spent tens of thousands of dollars on building new walls, and it sounds exactly the same!!???". Your answer is in that graph.
On the other hand, if you do it the way I am telling you, then you get the result on the right: An increase of twenty seven points, and a wall that blocks nearly one thousand times more sound that the original.
So once again, the choice is yours: You can do it the ignorant way, spend a lot of time and money, and get no results. Or you can do it the smart way, spend less time and money, and get much, much better results.
Sorry, the 1st floor "is" finished and my workshop. It's already filled with 3 workbenches and equipment and is and will be unavailable and will remain my workshop.
That's a real shame, since it would have been by far the cheapest option, and the best as well. Isolating a studio on an upper floor is a major big deal. Expensive, complicated, time consuming and never as good. There's a reason why most studios are built on the ground floor, and this is it. Those that are built on upper floors, have massive budgets to go along with the massive problems... or the owners are prepared to put up with the much lower isolation and all of the resonant issues brought about by having a studio on an upper floor.
FLOOR:
If you have any on alternatives to the Aurelux suggestions...
I already gave you that, but you ignored it. But let me do it again in more detail, as I might not have explained it clearly.
Here's the issue, in simple graphical format:
resonant-frequency-of-floating-floor-by-mass-and-gap-Graph---GOOD!!!.-S02.jpg
That graphs shows the amount of mass that you need on your floating floor, and the height of the air space under it, in order to get a certain resonant frequency. Remember that you need the resonant frequency to be an octave lower than the lowest note.
Take a close look: the solution you are proposing is roughly the top line in that graph, marked "5 psf floor load". That means that each square foot of the floor weighs about five pounds. Your proposal has a layer of plywood, a layer of MLV, and a layer of MDF. The MLV is 1 PSF, the plywood is about 2.2 PSF, and the MDF is about 2.8 PSF. So it's pretty much where that top dashed line is. The diagram shows 2x6 studs, so your air space is 5.5". Therefore the resonant frequency of that floor will be roughly 35 Hz. Meaning that it does not isolate below 70 Hz! Say goodbye to isolating the kick drum, toms, snare, bass guitar, low end of the electric guitar, low end of the keyboard, and any other instrument that puts out some energy below 70 Hz.
That's the plain simple acoustic truth. Not marketing hype, just plain science and physics. No isolation below 70 Hz.
So how do you get isolation, then? Look at the graph again. The bottom line, solid black, shows that with an air gap of 5.5 inches, using that system, the frequency would be 10 Hz. So it isolates from 20 Hz upwards. Since the range of human hearing starts at 20 Hz, such a floor will isolate the entire spectrum! Cool! Not only that, but if you follow that line over to the left, you'll see that it is pretty flat: at 5", 4.5" and 3.5" it is still really close to 10 Hz. You have to get all the way down to a quarter of an inch before it gets as bad as your option! With a 1.5" air gap, it will still isolate all of your instruments, even that six-string bass.
So what is the amazing secret of that solid black line? "60 psf floor load". In other words: "A lot of mass". You would need twelve layers of plywood, plus twelve layers of MDF, plus twelve layers of MDF to do that, and it would be 26 inches thick. That's how much mass you'd need to make your proposed floor work.
Or you could do it properly, with concrete.
Floated floors are normally made from concrete, because it is very high density: lots of mass in a thin layer. A simple reinforced concrete slab just 4" thick will get you 60 PSF.
So, since you asked for my recommendation, that would be it. If you want to float your floor, you will need to do it with a concrete slab, not a couple of flimsy layers of low mass plywood and MDF.
It will also save you some of that lost headroom: Your proposed floor needs a 5 1/2" air gap, plus more than two inches of other stuff (MDF, plywood, pucks, MLV, finish flooring, etc.), for a total of around 8". That means that your 8 foot ceiling is now down to 7' 4", and you don't yet have your inner-leaf ceiling in place. That will take up another 8" at least, so your final ceiling height (doing it your way) will be around 6' 8" or so. That's roughly the height of a standard doorway. You'll be able to reach up and touch the ceiling without even needing to straighten your arms (elbows bent)...
Had you considered that? Did they tell you that when you asked about the floor pucks?
Did you do the math, and notice that your final ceiling height will be very, very low? Are you OK with that? Are you aware that most music instruments sound bad when played in rooms with a low ceiling? Are you aware that the overhead mics on your drum kit would be just a couple of inches away from the ceiling, and therefore picking up major reflections from above, along with comb filtering and phase cancellation artifacts? Are you aware that most musicians do not like playing in rooms with low ceilings, because they think they sound bad? (Well, they really DO sound bad, and they know it). Low ceilings is not a good thing for a studio.
When I design studios for my paying customers, the most important thing I do for them is to maximize the ceiling height. I use every trick I can think of to get the ceiling as high as possible. Raised floors mean low ceilings, so I always eliminate raised floors, unless the room is really high already and can handle it.
Now back to my original questions
Once again, no offense meant, but you are asking entirely the wrong questions. You are asking about how to decouple the ceiling, when that is not the most important question you should be asking. Going back to the analogy of your buddy who wants to drive your car, you are trying to tell him about the importance of watching the road, using the rear-view mirror, driving below the limit, staying in his lane, etc. and he thinks none of that matters. He thinks the most important question about driving is: "Where do I plug in my iPhone?" He only asks that because he does not have a clue about driving a car, so the questions he asks are not the important ones: He cannot even grasp that knowing how to change gears and steer straight are far more important than plugging in his iPhone. He is thinking wrong because he doesn't know enough yet to think right.
Just like him, you are asking the wrong questions. Decoupling your ceiling is not the most important thing you should be looking at! There are far, far more important issues staring you in the face, and you have not seen them yet. There's a 700 pound gorilla sitting in your living room, and you are worried if the window is open or closed, so the rain can't get in...
Here are the questions you should be asking:
1. How much isolation do I need, in decibels?
2. What is the lowest frequency that I need to isolate?
3. How much mass do I need on each of my two leaves, and what depth air cavity do I need between them, to get the correct resonant frequency for my isolation system?
4. What total mass will that produce, considering all the construction materials, gear, instruments, and furniture?
5. Can my existing floor handle that load?
6. How can I beef up the structure of the building such that it can handle the extra load?
7. How can I modify the existing two-leaf walls to make them into single-leaf walls?
8. Is there anything I can do to increase the ceiling height?
9. How can I make the control room symmetrical?
10. Am I making the best use of the available floor area, without wasting any space?
11. Are my sight lines good, broad, and clear, without obstruction or needing to turn my head all the time?
12. What air flow rate do I need for each of the rooms, in my HVAC system?
13. What is the maxim air flow velocity that I can allow for the HVAC registers in each room?
14. How big do my HVAC ducts need to be to achieve that?
15. How much heating / cooling / dehumidifying capacity do I need for each room?
16. How big will my HVAC silencer boxes be, and where can I put them to minimize incursion into the rooms?
17. What design philosophy should I use for the control room? Should I go with RFZ, CID, NER, LEDE, MR, or something else?
18. What is my room ratio, and how does that compare to the top dozen known good room ratios? Can I improve mine?
19. What decay rate and frequency response curve should I be aiming for in each room?
20. How will I feed electrical power into my studio without trashing the isolation, and how will I distribute it internally?
Those are just the top twenty, but there are many more that are equally important. If you do not yet have detailed answers for every single one of those, then there's no point asking where to plug in your iPhone, or how to decouple your ceiling.
I'm sure you think you are asking the right question, and that you have all your bases well covered, and that your design is wonderful and will work fantastic, but take it from someone who does this for a living: your plan so far is not good, it will not work well, you don't have all your bases covered, and you are asking the wrong questions while not asking the right ones.
You didn'tanswer it,
That's correct: I did not answer it. For a very good reason: it isn't the question you need to be asking! When you get to the point of really needing that information, after you have asked and found answers for all of those other questions, then I'll be happy to provide the answer. I can't do it now because it won't make any sense to you until you have workable design and a full understanding of the issues, just like your hypothetical brake-less buddy with the iPhone would not be able to understand what the oil warning light means and what to do if it comes on: He cannot grasp that until you first explain to him how the engine works, why it needs oil, what will happen if it has no oil, what type of oil to use, where to put it in, and how much to put in. All you can tell him right now, is that if the light comes on he must stop immediately and call an expert. That's the same advice I can give you right now about your studio design: stop and call an expert. You don't yet know enough to even understand all the things that are wrong with your design. So either you should call an expert to design it for you, or you should stop and take the time to learn enough so you can understand and answer all those questions, then you can do it yourself.
I'm sure that none of the above is the answer you expected when you came to the forum, but you did come here for help, and that's the very best help I can give you right now.
If you do nothing else, please read through the first few posts in this thread:
http://www.johnlsayers.com/phpBB2/viewt ... =2&t=17363 . That's a case very similar to yours (in concept, not details). He also came to the forum to show us what a wonderful job he was doing with building his studio, and how great it was going... but very soon learned that he was doing a number of things wrong, and that his studio was going to be a disaster. Fortunately he was smart enough to eventually admit that he screwed up, swallow his pride, ask for expert advice, tear it all down and start again. In the end, he has a fantastic studio, because he spent the time to learn enough to understand why everything he had done was wrong, and how to fix it. He's a great guy, and in the very first post on his thread he tells it like it is: how he screwed up, how he got help, and how happy he is with the result.
The only real difference between you and him, is that you have not built anything yet: he had. He was far advanced with the build when we gave him the sad news about why it was heading into disaster. You are not that far yet: you have the chance to do it right from the start, avoid making all the mistakes he made, avoid all the frustration, expense, wasted time, etc.
I appreciate your criticism, but this is the area I'm giong to utilize and looking for solutions.
Paraphrase: "I appreciate your telling me about the gear shift and the rear view mirror, but I'm going to plug in my iPhone anyway, I don't need to know what a "brake" is, and I just need solutions for doing what I think is important!..."
(Sorry for the sarcasm, but sometimes it's the best way to get the point across in an amusing manner...)
- Stuart -
A three leaf wall will always have worse isolation than the equivalent two-leaf wall, especially in the low frequency part of the spectrum such as the rumble and noise from aircraft, as well as traffic, thunder, rain, drums, bass guitar, keyboards, ....
