The space will be used as one room studio - control room/tracking room one space.
It can't be both at once! As I mentioned above, he acoustic requirements for a tracking room are very different from those for a control room. There's a document called ITU BS.1116-3 that clearly defines exactly what the acoustic characteristics of a control room should be (google it), but basically it has to be neutral. Meaning that it has no sound of its own: it does not "color" the sound in any way, and the time-domain response is rather short. It has to be. But a tracking room is rather different: it is supposed to enhance the sound of the instruments. It is supposed to be warm, vibrant, pleasant, etc. acoustically. So you can't have it both ways! If you treat your room so that it can be used as a tracking room, then it will fail dismally as a control room, and your mixes will be terrible: engineers will hate it, and not want to mix there. On the other hand, if you treat it to be perfect for mixing, then it will sound awful for tracking: musicians will hate it, and not want to play there.
There is one solution: you can make the treatment devices in your room "variable": with parts that open, close, slide, flip, rotate or otherwise move in some fashion, exposing different parts of the device to the room, and achieving different response. It is possible, and I have done a few rooms like that, but it isn't easy, and it is expensive.
A space to record and produce music, mostly overdubs, maybe sometimes drums, bass cabs,
So quite a broad range of very different instruments and purposes....
Having a very low ceiling and floor completely reflective, I think the ceiling will have to be as absorbent as possible,
The ceiling will have to be absorbent, yes, but NOT "as absorbent as possible"! That would sound really bad for instruments, and not so good for a control room either. If your entire ceiling is major thick absorption, the room will be very dead, dull, lifeless and unbalanced. It will not be good for tracking, and especially not for drums. You will need SOME sections of the room ceiling that are highly absorptive, yes, but NOT all of it. The rest will likely need to be partly absorptive, partly reflective, and partly diffuse.
if not I'm going to have problems for both purposes tracking and mixing.
No you're not!
If you DO make the entire ceiling highly absorptive, THEN going to have problems for both tracking and mixing. Rooms should be balanced and tuned for the specific purpose.
Here's a link to a thread for a control room that we are in the process of tuning right now. It shows you how that process should work:
http://www.johnlsayers.com/phpBB2/viewt ... =2&t=21368 . And here's a thread for a control room that is finished, showing the final outcome:
http://www.johnlsayers.com/phpBB2/viewt ... =2&t=20471 Both of those have large amounts of absorption in the ceilings, yes, but in both cases it is carefully calculated and placed in the specific spots where it is needed. In some places it is several feet thick, while in others, it is just an inch or so thick, or none at all. And both of those are control rooms, which need much more absorption than live rooms.
all I can hear now are some footsteps
And you will still hear that, if you don't decouple your inner leaf! Plus a lot of stomping, yelling and screaming, when you are tracking drums, as they get really angry at your noise!
Ceiling wise is more about my sound coming out too loud.
Right! And it's the same thing: isolation works equally in both directions. If the ceiling transmits their sounds to you, it also transmits your sounds to them. And since your sounds are ten thousand times stronger, it will be many times worse for them...
The ceiling is a bit irregular, there are those columnes and white beams which are structural and keep the ceiling together, those white structural beams are below the heigh level of the ceiling joists of 2.09m.
That's fine. There are methods for working around that type of problem.
In term of structural load I felt safe with those and didn't see the issue in loading with some layers of drywall.
I'm pretty sure that these guys "felt" their ceilings were perfectly safe, too...
structural-ceiling-failure-03.jpg
structural-ceiling-failure-07.jpg
"feeling" has no place in construction. The only valid opinion is that of a qualified expert. As I mentioned, you will be adding about a ton of extra weight to that floor above you, IN ADDITION to what it is already supporting. If it does fail, and you did not get it approved by a qualified structural engineer and passed by inspectors, then YOU are legally liable for everything: Both criminally and civilly. Are you SURE you are prepared to take on that responsibility?
To drop a floating ceiling I'd need to go below that height of those white beams, and I'm going to have 1.95m height remaining floor to ceiling, to treat with clouds etc. not doable for me, too claustrophobic, prefer to have less isolation.
So that's solved then! If you reject having a slightly lower ceiling, then you reject having isolation. So what you have now is all that you will ever get. It's that simple. End of story. (Although you are wrong about it being 1.95m, but that's another story, since you already rejected isolation).
OK, so since you have already decided that you do NOT want any additional isolation, and you are fine with what you have right now, that takes us on to the question of treatment:
Do you want to design and build variable treatment devices, so that you can use your room successfully for both tracking and mixing? Or do you want to dedicate the treatment for only one of those, and to the other in a different location? For example, if you decide to use this room for mixing only, then that's great: we can show you how to make it usable for that, and then you can find another room, some other place, to use for tracking. That would be the best option, since there's no way that this will be any use for tracking, regardless of treatment. The ceiling is just way too low for that. It doesn't matter how much insulation you put up there, it will never be possible to get usable sound from your overhead mics, due to the powerful comb filtering created by the ceiling. So your best option is to turn this into a mixing room only (control room), which is barely doable, and track elsewhere.
In terms of walls, 2 are with bad old drywall, the other 2 walls are made of concrete 45cm deep, with 3 windows on there (lovely!-good light). It would be too expensive and work load to build walls for isolation on those sides of concrete, with 3 extra windows, especially because not necessary. Is not a residential area so the sound going out of the windows is not an issue. This is the main reason I wasn't planning in going full room in the room and fully decoupled ceiling.
OK. No problem. We have already established that you do not need isolation for this room, and you are fine with the way it isolates right now, so there's no need to build any walls at all: it's never going to be better than the way it is now, and trying to do that without also isolating the ceiling would just be a huge waste of time and money. So just do whatever you feel like with the walls to make them look pretty, because there's nothing you can do to them to substantially improve isolation unless you also isolate the ceiling. So that's already figured out, and the next step is treatment.
The other music recording studio there is in a room next to me on the same floor where I am. Going to build 2 MSM partitions on the other 2 walls remove internal layer of drywall, reinforcing mass and insulating existing partition, then extra stud wall, just where the 2 columns are (so that they will be hided within the partition, with with that air gap, insulated and then drywall sandwiches.
Sorry, but the won't work.
Have you ever seen an aquarium? A fish tank? They are simple metal frames, with glass on all sides, filled with water. Sound behaves a lot like water, in many ways. Now, what you are saying here is the same as if someone said he was going to build an aquarium in his living room, but decided that he only wanted to see the fish from the front and one side, so he only put glass in those two sides.... How well do you think his tank will hold water? Exactly as well as a studio that is isolated on only two sides! It's that simple. With the fish tank, unless you put glass on ALL sides, the water will simply splash out all over the place, totally ignoring the sides that do have glass, and exiting through the sides that don't. Same with your room: if you don't isolate it the same on ALL sides (including the ceiling) the sound will simply ignore the walsl that you did build, and "splash out all over", bypassing them through the ceiling which you did not build.
It's that simple.
Unless you isolate your ceiling too, you will be wasting money by isolating your walls.
To drop a floating ceiling I'd need to go below that height of those white beams,
You don't have a CHOICE! No matter WHAT ceiling you do, the height of those beams is the lowest point of your ceiling! But there are methods for working AROUND those, so that there will be low points ONLY where those beams are, but not the rest of the ceiling.
But you already rejected isolation as an option for your room, so that's a moot point, and you should be thinking only about your treatment options at this point, since isolation cannot improve if you do not isolate the ceiling.
Going to build 2 MSM partitions on the other 2 walls
MSM doesn't work like that. It is a SYSTEM that involves the entire room, not just a single wall. Saying that you will build two MSM walls is the same as saying you will put glass on two sides of the fish tank. You can build the best MSM wall on the planet, but it will have no effect unless you build the entire room to the same level.
but for this situation I'd like to think that adding those 3/4 layers of drywall mass (around 1000kg?) in a sealed MSM system, even if not decoupled,
Then you have completely mis-understood how MSM works! If it is not decoupled, then it is not MSM. Period! Sorry to be so harsh, but you are not understanding the basics here, which is why you are assuming that your plan will work, when in fact it won't.
Here's how it really works: MSM stands for "Mass-Spring-Mass" It is a principle of physics that also works for acoustics. It is a resonant system, and it works because you have the "mass" on one side and the "mass" on the other side, with a spring joining them. If you nudge one of the masses, then it will bounce back and forth on the spring at a fixed frequency, and it will transmit energy to the other mass, through the spring, AT THAT SPECIFIC FREQUENCY. But at all other frequencies, it will NOT transmit energy to the other side. ONLY at the resonant frequency. That's why you have to tune your walls to the correct frequency. In a wall or ceiling, the two "masses" are the sheathing on either side (usually drywall, but it could also be concrete, glass, wood, etc.), and the "spring" is the air in between the two masses. It is a tuned system, and you tune it by changing the amount of mass and the depth of the air cavity.
But that's not what you are planning to do. You want to build a ceiling where there is no spring! Instead, you want to replace the spring with a solid wood bar, that completely joins the mass on one side to the mass on the other side, and therefore it will transmit sound at ALL frequencies! Every single frequency will get through your ceiling, because you have a hard, slid, rigid direct path between the two masses. Any sound striking the drywall below will be directly transmitted through the joists and into the floor above. That floor will act just like the cone of a loudspeaker, transmitting the sound waves into the entire room, very efficiently.
If you do NOT decouple, then you do NOT have an MSM system. There is some MSM effect in the gaps between the joists, sure, but that is completely overwhelmed by the solid transmission of sound through the joists.
By directly attaching your drywall to your joists, you are allowing sound to get into the actual building structure, and once that has happened, it can go anywhere it wants. Once you have vibration in the joists and studs, it will not just go "anywhere": rather, it will go "everywhere", including other walls in the building, and other floors, and other ceilings.... thus bypassing your attempts to stop it.
Thus, if you do not decouple, then you do not isolate. Period. End of story. An MSM wall that has solid mechanical connections across it, is not an MSM wall: it is just a fully-coupled two-leaf wall. Period. End of story.
in a sealed MSM system, even if not decoupled, would be quite of a drastic improvement in STC
No it would not. Sorry. And STC is not a valid measurement of isolation for studios anyway. Here's why:
Forget STC. It is no use at all for telling you how well your studio will be isolated. STC was never meant to measure such things. Here's an excerpt from the actual ASTM test procedure (E413) that explains the use of STC.
“These single-number ratings correlate in a general way with subjective impressions of sound transmission for speech, radio, television and similar sources of noise in offices and buildings. This classification method
is not appropriate for sound sources with spectra significantly different from those sources listed above. Such sources include machinery, industrial processes, bowling alleys, power transformers,
musical instruments, many music systems and transportation noises such as motor vehicles, aircraft and trains. For these sources, accurate assessment of sound transmission requires a detailed analysis in frequency bands.”
It's a common misconception that you can use STC ratings to decide if a particular wall, window, door, or building material will be of any use in a studio. As you can see above, in the statement from the people who designed the STC rating system and the method for calculating it, STC is simply not applicable.
Here's how it works:
To determine the STC rating for a wall, door, window, or whatever, you start by measuring the actual transmission loss at 16 specific frequencies between 125 Hz and 4kHz. You do not measure anything above or below that range, and you do not measure anything in between those 16 points. Just those 16, and nothing else. Then you plot those 16 points on a graph, and do some fudging and nudging with the numbers and the curve, until it fits in below one of the standard STC curves. Then you read off the number of that specific curve, and that number is your STC rating. There is no relationship to real-world decibels: it is just the index number of the reference curve that is closest to your curve.
When you measure the isolation of a studio wall, you want to be sure that it is isolating ALL frequencies, across the entire spectrum from 20 Hz up to 20,000 Hz, not just 16 specific points that somebody chose 50 years ago, because he thought they were a good representation of human speech. STC does not take into account the bottom two and a half octaves of the musical spectrum (nothing below 125Hz), nor does it take into account the top two and a quarter octaves (nothing above 4k). Of the ten octaves that our hearing range covers, STC ignores five of them (or nearly five). So STC tells you nothing useful about how well a wall, door or window will work in a studio. The ONLY way to determine that, is by look at the Transmission Loss curve for it, or by estimating with a sound level meter set to "C" weighting (or even "Z"), and slow response, then measuring the levels on each side. That will give you a true indication of the number of decibels that the wall/door/window is blocking, across the full audible range.
Consider this: It is quite possible to have a door rated at STC-30 that does not provide even 20 decibels of actual isolation, and I can build you a wall rated at STC-20 that provides much better than 30 dB of isolation. There simply is no relationship between STC rating and the ability of a barrier to stop full-spectrum sound, such as music. STC was never designed for that, and cannot be used for that.
Then there's the issue of installation. You can buy a door that really does provide 40 dB of isolation, but unless you install it correctly, it will not provide that level! If you install it in a wall that provides only 20 dB, then the total isolation of that wall+door is 20 dB: isolation is only as good as the worst part. Even if you put a door rated at 90 dB in that wall, it would STILL only give you 20 dB. The total is only as good as the weakest part of the system.
So forget STC as a useful indicator, and just use the actual TL graphs to judge if a wall, door, window, floor, roof, or whatever will meet your needs.
would be quite of a drastic improvement in STC and also low frequency transmission
Wrong again! It would be WORSE for low frequency isolation, because the resonant frequency of the cavities between the joists will be in the low frequency range, and therefore the isolation would be DEGRADED at low frequencies, NOT improved.
It is something I can maybe think in the future
That's not a good plan. If you do all this effort and construction, then find that it does not work (and it won't) you will have to tear it all down again and start over, doing it correctly the next time. So you spend double the money, double the time, and double the effort. TO me, that doesn't seem like a smart way of building a studio. It is far better to learn the principles, do the math, design it right, and get it correct the first time.
still having improved considerably the isolation,
That's the problem: what you are proposing will NOT improve the isolation considerably. It won't improve it at all, in fact, and will likely make it worse at some frequencies, due to uncontrolled resonance.
and want to work as best as possible within resources and limitations I have.
... perhaps, but that's not what you are actually doing. You might think you are, but you aren't. You are trying to fight against the laws of physics, hoping and wishing that you can win, but you can't.
OK, so maybe I'm being a bit harsh here with my comments, but that's only because I need to grab your attention, and point you at the things you are planing to do wrong, hopefully so you will realize that your plan is seriously flawed, then you can learn how to fix it.
So here's the bottom line: I can't tell you what to do, and I can only point you in the right direction. But if that were my room, I would make it into ONLY a control room, fully isolating the ceiling and walls, with inside-out construction all around, and live with the slightly lower ceiling, since it can still be usable (borderline) for a control room, but not for a live room. I would tune the hell out of that room to get it as good as it possibly can be (withing the laws of physics), then I would then find a different room to use for tracking live, or switch to purely electronic instruments.
But that's just me. Other people might have different opinions...
- Stuart -
Excellent! You already have the best possible floor.
