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PostPosted: Wed Mar 22, 2017 8:15 am 
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What is a mini split? You lost me there, I'm afraid.


Ductless mini split, HRV
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PostPosted: Wed Apr 05, 2017 7:08 am 
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Location: Finland
I still have couple unanswered questions.
  • Are the shape and size for my control room good?
  • Is it essential to caulk the outer leaf? If so, I will caulk the corners with acoustic sealant. I'll probably use this stuff: http://www.casco.eu/global/casco/?pc=97&p=642
  • But what about the vertical seams? The drywool is double layer with offset seams, ie. the top layer seam is in different place than the bottom layer seam. I'd like to think that's air tight enough, right?
  • And what about the holes? Would it be a good idea to cut some round pieces of drywall, plug the holes with them and seal them tight with caulk?


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PostPosted: Mon Apr 10, 2017 10:25 pm 
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Guess what! I tamed Sketchup! Woohoo!
Attachment:
made_with_ketchup.jpg


IMO this is my best plan yet. All the waste of space issues are resolved if I do it like this. I decided to scrap my earlier corner control room plan after reading some comments on this forum and elsewhere regarding small control rooms. My control room, as I had planned it, was just waaaaay too small. This is hopefully a lot better. I also am not going to build inside-out. I did one such plan and decided that it carries no real benefit. For one, it seems harder to build that way, and if I would want that, I could just build another frame, wool it and wrap it in fabric and attach no drywall to it. Or I can just build or buy sound treatment elements and hang them on the wall.

I have not drawn the soffit mounts, but there's plenty of space for them. The window is a bit of a discrepancy in the symmetry of the room, but it is a compromise. Either that or no window at all.

For ventilation, I am going to punch another intake for the live room (with a silencer box) and swap all existing ventilation ducts (except the one penetrating the roof) with this (duct isolated with PE foam; my hope is that it will work in mechanically isolating the duct from the wall structure).

I did some calculations with ModeCalc. These are for the control room:
Attachment:
modes_cr.jpg

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freq_cr.jpg


These are for the live room:
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freq_lr.jpg


I don't think it is possible to find a better space distribution for the rooms, so that the ratios would align better to the recommendations.


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PostPosted: Thu Apr 13, 2017 10:49 am 
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Guess what! I tamed Sketchup! Woohoo!
Great, Simon! Once you get the hang of it, it's not so bad. Glad you figured it out!

Quote:
IMO this is my best plan yet. All the waste of space issues are resolved if I do it like this. I decided to scrap my earlier corner control room plan after reading some comments on this forum and elsewhere regarding small control rooms. My control room, as I had planned it, was just waaaaay too small.
It looks pretty good, I must admit.

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I also am not going to build inside-out. I did one such plan and decided that it carries no real benefit.
... or perhaps you just didn't realize what the benefits are? :) I frequently design inside-out rooms, and the benefits are very real.

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For one, it seems harder to build that way,
True, but the benefits are worth the effort.

Quote:
and if I would want that, I could just build another frame, wool it and wrap it in fabric and attach no drywall to it.
:shock: And you don't see that as a disadvantage? You don't see the wasted space in that plan? The extra effort? The higher cost? The poorer acoustic response?

Quote:
Or I can just build or buy sound treatment elements and hang them on the wall.
Ummmm... same as above: you don't see that as a disadvantage? You don't see the wasted space in that plan? The extra effort? The higher cost? The poorer acoustic response?

You can avoid all of that by building inside out.

Quote:
I have not drawn the soffit mounts, but there's plenty of space for them.
:thu: There's not as much space as you think there is, but still enough.

Quote:
The window is a bit of a discrepancy in the symmetry of the room,
IT's not a problem. It is far enough behind your head that it should not be an issue.

Quote:
For ventilation, I am going to punch another intake for the live room (with a silencer box) and swap all existing ventilation ducts (except the one penetrating the roof) with this . . .
That looks like sewer pipe to me, not HVAC duct! Maybe you guys do it that way where you live, but in other places around the world, it is done with simple "flex-duct", like this:

Attachment:
hvac-flexduct-M-KE_RGB.jpg


Quote:
I did some calculations with ModeCalc.
That's a mistake. That calculator is no use, as it only considers axial modes. It does not take into account the tangential modes, or the oblique modes. You can safely ignore what that calculator is telling you. Use one of the good ones, that gives you the full set of modal information about your room. These two are my favorites:

http://amroc.andymel.eu/

http://www.bobgolds.com/Mode/RoomModes.htm


- Stuart -


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PostPosted: Thu Apr 13, 2017 5:18 pm 
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Soundman2020 wrote:
:shock: And you don't see that as a disadvantage? You don't see the wasted space in that plan? The extra effort? The higher cost? The poorer acoustic response?


To be honest, no, I don't. Unless I have totally misunderstood something (again :cry: ).

Have a look at this:
Attachment:
which_method_takes_more_space.jpg


To my understanding and according to what I've drawn here, building conventionally only takes up 10mm more space. To my understanding, judging by what I have drawn, the acoustic response would be pretty much the same. And the conventional way would be easier to build. For instance, how would I caulk seams I cant reach? Sure, extra frame would be an extra cost, but not that much.


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PostPosted: Wed May 10, 2017 6:30 pm 
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My control room is starting to take shape. Oh well, this is very exciting. It has an experimental feel to it, but I'm positive that it will exceed my expectations in the end.

I had originally planned for 32mm (2 * 16mm) wall surface thickness but I will have to settle for 26mm (2 * 13mm). Thus the mass for a single leaf will be 16.8kg/m^2 (2 * 8.4kg/m^2). The window will be a 4mm + 4mm laminated glass. Glass weighs roughly 2.5kg per mm per m^2, so the glass will be about 20kg/m^2, a bit heavier than the wall. I have no idea what the resonant frequencies for these elements are or how to calculate them. The equations I did find look like hebrew to me.

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PostPosted: Thu May 11, 2017 3:00 am 
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Whoaaa!!! Slow down! STOP!!!!!! Lot's of issues here... BIG ones!

Quote:
I have no idea what the resonant frequencies for these elements are or how to calculate them. The equations I did find look like hebrew to me.
So you have no idea if your room will isolate or not? And you already started building it? :shock: :roll:

The equations are dead simple:

For a single-leaf barrier:

TL = 14.5 log (M * 0.205) + 23 dB
Where: M = Surface density in kg/m2


For a two-leaf wall, you need to know the above for EACH leaf (call that "R1" and "R2"), then you need to know the resonant frequency of the system, using the MSM equation:

f0=c[(m1+m2)/(m1 x m2 x d)]^0.5

Where:
c=constant (60 if the cavity is empty, 43 if you fill it with suitable insulation)
m1=mass of first leaf (kg/m^2)
m2 mass of second leaf (kg/m^2)
d=depth of cavity (m)

Then you use the following three equations to determine the isolation that your wall will provide for each of the three frequency ranges:

R = 20log(f (m1 + m2)) - 47 [for the region where f < f0]
R = R1 + R2 + 20log(fd) - 29 [for the region where f0 < f < f1]
R = R1 + R2 + 6 [for the region where f > f1]

Where:
f0 is the resonant frequency from the MSM resonant equation,
f1 is 55/d Hz
R1 and R2 are the transmission loss numbers using the mass law equation

And that's it! Nothing complex, no Hebrew. Any primary school student can do that. It's just simple addition, subtraction, multiplication, division, and square root.

That will give you a very good idea of the amount of isolation you will get in each frequency range, and also the lowest frequency that your wall will isolate (f0 x 2).


Next, your door and window framing is entirely inadequate, unsafe, probably illegal, and certainly does not meet international building code.

Please always keep in mind that if you build something that does not meet code, and it collapses, your insurance will NOT cover the damages, medical expenses, compensation payments for injuries, legal fees, funeral costs, etc. YOU will be personally responsible for all of that. If someone dies as a result, you will probably also be criminally liable for their death. So it's probably a good idea to make sure your framing is legal, safe, and meets code. Yours is not legal, not safe, and does not meet code.

On each side of a door or window opening, you need triple studs: two kings, plus one combination of cripple plus jacks, or one king and two combinations of cripples plus jacks. You also need a header above the door or window, supported on the jack studs, and of dimensions sufficient to support the weight above. This is the concept of correct door framing:

Attachment:
GENERIC-door-framing-detail.jpg


Attachment:
AGGLAS--UK-V6-S0143-door-framing-detail-2.png


How it looks in real life:

Attachment:
door-framing-three-studs-GOOD!!!.jpg




For windows, it is similar:

Attachment:
WINDOWS-FRAMING-02.jpg




Next, you only have ONE top plate on each wall, but standard framing requires TWO top plates (often called "double top plate"). Using only one is unsafe, and probably illegal.

Next, you are using 2x4s for the ceiling joists, but there's no way that 2x4s can span that distance with the load you'll be putting on them. That ceiling WILL collapse. You cannot span much more than about 6 feet like that. You will need at least 2x6 joists for that, and perhaps even larger if you need to hang heavy things from the ceiling, such as acoustic treatment...

So all of that framing has to come down, and you need to re-design it correctly. It cannot be fixed without taking it down. And since you clearly don't understand structures, weights, loading, or risks, you will have to hire a structural engineer to check your new design BEFORE you build it.

Quote:
It has an experimental feel to it, but I'm positive that it will exceed my expectations in the end.
Framing should NEVER be experimental, when your life is at risk, and I'm positive that my expectation is that your room will exceedingly fail structurally, and you will be liable for the consequences, legally, criminally, civilly, and financially. If you are still alive after the structural failure, of course.

That's just the structural issues. Now for the acoustic issues:

You have multiple large holes in your outer leaf, therefore you have no isolation, regardless of what you do with the inner leaf. Most of those appear to be for electrical wiring, but you cannot have more than one single penetration of your leaves for that, and it has to be done correctly, using decoupled conduit, like this:

Attachment:
Conduit-isolation-1.png


Attachment:
Conduit-isolation-2.png


Attachment:
Conduit-isolation-3.png


I already warned you about this in my very first response to your initial post. I warned you about this a second time in a later post, and I even gave you a graph showing how severely that will damage your isolation, but it seems you chose to ignore that. I also gave you the exact same three images as above, on how to do wall penetrations correctly, and that, too, you have ignored.

In that same post, I said this: "It seems to me that you are rushing ahead with this studio build, yet you don't have the necessary acoustic or construction knowledge to do it, and you don't have the experience, and you don't even have a design! You should first learn how to do it, then design it, and only then start building it."

Yet another thing that you have ignored.

I also said this: "I'm hoping you will be one of the smart ones, who stops, learns, designs, then does it right. Not one of the "others", who goes ahead and does it wrong, wasting a lot of time, money end effort, hoping that the equations and laws won't apply to them.... then getting really lousy results." It looks like my hopes were not realized, and you turned out to be the second type of studio builder, not the first type. Except in your case, the results are not only lousy, but also dangerous.

I'm not even sure why you came here: most members come to the forum to get advice on how to build their studios, but so far it seems the reason you came here is to ignore all advice from people who know how to do it, and to just go ahead and do it your way, regardless of the consequences....


Next, there appears to be a very small ventilation duct poking right through both leaves in one place, but there are no silencer boxes on it. The size of that duct seems to be too small for that room anyway, but with no silencers on it, there is also no isolation. I did warn you about this too, and I gave you a large number of links to threads with typical silencer boxes (twice!), but you chose to ignore that warning as well....

I also pointed out the error with the location of your vapor barrier on the outer-leaf, and you never said that you had fixed that, so I also have exceedingly high expectations that you will have problems with mold and rot inside your walls, sooner or later. If your vapor barrier is in the wrong place, then the humidity in the air will condense onto it, forming liquid water drops, which will run down to the floor, where it will wet your wood framing, and your concrete floor, causing the wood to expand, which will break the seals and pull the nails loose. The water will also provide the ideal conditions for mold to grow, and will rot the wood. Those are my expectations....

So it seems you are wasting a lot of money, time and effort here. This is the reason why we always highlight, promote, and heavily suggest that it is extremely necessary to fully plan the entire studio, in complete detail, and confirm that you have it all correct, before you ever start building anything. I did tell you all about this in several earlier posts.

But seeing you chose to completely ignore all of the advice you got here, your only possible course of action now is to take down all the inner-leaf framing, take off the drywall on the outer leaf walls so you have access to the electrical wiring in order to correct it, then put up new drywall (you can't re-use the same stuff, since it already has holes in it), then re-design your inner-leaf framing in accordance with normal, safe, legal framing practices for load-bearing structures, get it checked by a structural engineer and by the building inspector who will have to sign off on your framing, and only then start building it again.

Please refer back to my original comment in my first response to you: "It seems to me that you guys are racing ahead way to fast, with no design and no provision for isolation, or acoustics. You should probably slow down until you have the complete design fully finished, with all aspects taken care of.". I did warn you back then, but you chose to ignore that. Now you are paying the price.



- Stuart -


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PostPosted: Fri May 12, 2017 3:11 am 
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Stuart, I don't know what to tell you. I have asked many questions and to most of them I have gotten no answer. I've asked for clarification on many issues you have raised, but I have received no comment back. This is all extremely confusing.

Quote:
Next, your door and window framing is entirely inadequate, unsafe, probably illegal, and certainly does not meet international building code.


I don't know what to tell you here either. I am working with a professional, I am not building myself. I am counting on him knowing how things need to be built. He has even consulted a structural engineer on some load bearing concerns he had, and was assured everything is okay.

Quote:
You have multiple large holes in your outer leaf, therefore you have no isolation, regardless of what you do with the inner leaf.


I asked for a more elaborate explanation for this one, because I don't understand how that is. I have no vocabulary to express to my constructor what to do about this and why.

Quote:
Next, there appears to be a very small ventilation duct poking right through both leaves in one place, but there are no silencer boxes on it.


I thought I could build a silencer box on the inside... I did ask about that, too.

Quote:
I also pointed out the error with the location of your vapor barrier on the outer-leaf, and you never said that you had fixed that, so I also have exceedingly high expectations that you will have problems with mold and rot inside your walls, sooner or later.


The barrier extends low enough. At the lower level where there is no barrier, there is also nothing that can rot, just concrete.

Quote:
I'm not even sure why you came here: most members come to the forum to get advice on how to build their studios, but so far it seems the reason you came here is to ignore all advice from people who know how to do it, and to just go ahead and do it your way, regardless of the consequences....


I'm sorry you feel disappointed. I really am. And I don't know what more I can say anymore. I guess this is a total failure then. Thank you for your help, and I really do mean that. I felt like I was bothering you and asking too much, so I thought perhaps I should just gather the information I can and work with it as best as I know and understand how.

I'll go cry in a corner now, because I truly feel defeated. Bye.


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PostPosted: Fri May 12, 2017 7:12 am 
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I don't know what to say, Simon. I warned you multiple times, in practically ever reply I posted, that you were rushing ahead too fast, needed to slow down, needed to do a full, complete, detailed design, needed to pay attention to the details, etc. I'm not sure why you ignored those warnings: maybe you just thought I didn't know what I was talking about, or that things are different in Finland, or that you had found a better way to do things. I'm not sure if that's the case. If so, I design studios for people all over the world, and the building codes are fairly similar everywhere. Even with that experience, I always tell my customers to get a locally qualified and certified architect/structural engineer to check my designs, and make sure that they meet local regulations and codes.

With that experience, I am not aware of any country that allows framing walls and ceiling the way you are doing it. No place that I know of allows single top plates in wood framed load-bearing structures, nor walls where the doors and windows have no lintels, no jacks studs, no cripple studs (sometimes also called "trimmers"), no noggins, and the ceiling framing is of dimensions that are too small to support the dead load and live load. So I'm not sure about how structural engineers and builders are trained or certified or licensed in Finland, but I can tell you that the structure you have there would not pass inspection where I live, nor in any of the countries where I have designed studio. The structure is not safe. It does not have enough structural integrity to support the ceiling and the doors. It will warp, twist, bend, and eventually fail. The door will jam, because the framing will not be able to hold it upright: as you open the door, it will sag as the framing bends, and that sag will very soon become permanent: the door will not be able to open or close, because it will sag so far that it bangs into the threshold and the jambs.

2x4 ceiling framing cannot safely span more than about 6 feet with the load you are applying to it. If you do not believe, then check some on-line span tables or span calculators. Here too it will sag, and eventually it will fail and fall.

If you think I'm lying to you, and that your "structural engineer" and "builder" are telling the truth, then all you need to do is to spend five minutes on Google, searching for "basic wall window door framing techniques", and you'll find things like the following:

Attachment:
basic-framing-01.jpg


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Those are standard framing practices, all over the world. Since the laws of physics are the same in Finland as everywhere else, I would expect that you have to frame the same way.

Quote:
I am working with a professional, I am not building myself.
Does he have experience designing and building studios? Is he familiar with acoustic isolation methodologies? How many recording studios has he designed and built? Have you been to visit them, to make sure they really do work? Ask him what MSM frequency he has tuned the wall system for, and what the total transmission loss will be: if he cannot answer that, then he's not the right guy to be designing a wall system for acoustic isolation. Ask him what deflection will be caused on the joists due to the complete load on them. Ask him what the dead load is, and ask him if he considered a suitable live load factor. If he can't answer those immediately, then he's not the right guy to be designing load bearing structures.

Quote:
I thought I could build a silencer box on the inside... I did ask about that, too.
And I said the following: "...you would be wasting your time and money if you only have one wall and a couple of HVAC silencers. Sound would flank around all of that, doing through the weakest, simplest paths: the other walls, the ceiling, the electrical system, the windows, the doors....

But anyway, here are some examples of silencer boxes that have been built by forum members:
"

Maybe you didn't notice that? And I also added the following:

"But you also need to do the math: You need to ensure that the cross sectional area of each part of your HVAC system is correct, such that you are delivering the correct air flow rate (room changes per hour, CFM, M3/h, volume per unit time) at the correct air flow velocity (fpm, M/S, distance per unit time), while keeping the static pressure low enough that the AHU or HRV fan can handle it, while also ensuring that the cross sectional area changes by a factor of at least 2 at the entrance and exit of each silencer box, and that the final path into the room is long enough that the turbulent flow is minimized at the register, and also ensuring that the surface density of the silencer box walls is sufficient to maintain the level of isolation required for the room... It's quite a challenge! It takes a bit of math and ingenuity. ". Did you do all of that? What size duct do you need? What flow rate do you need? What flow velocity do you need? What is your sensible heat load? What is your latent heat load? What is the static pressure going to be? How much insertion loss do you need? You need to be able to answer all of those.
Quote:
The barrier extends low enough.
You are still missing the point! It should no be there AT ALL! It is in the WRONG PLACE! In cold climates, like Finland, the vapor barrier must go right up against the WARMEST surface in the wall. It must not be against a cold surface, or in the middle of the wall cavity. In a two-leaf MSM construction system, them warmest surface is the INNER LEAF, not the outer leaf. The vapor barrier must go on your inner leaf.
Quote:
I guess this is a total failure then.
No, it's not a total failure: it can be fixed. It's not hard to fix it, at this point. All you have is some framing, and that's easy to take down and rebuild properly. It's not a big deal Any good framer would be able to pull all of that out in a few hours, maybe one day, maximum. With the framing out, you'll be able to get the drywall off and fix your electrical problems: another day. Then you can stop right there, and spend the time needed to design the entire studio correctly including correct framing. Don't do anything else until the design is complete, and verified, and double-checked, in all aspects. Only when it is fully done, then you can start framing the walls again: they are simple, so it should be possible to do that inside a day, or maybe two. Then another few hours to frame the ceiling, and you'll be back to where you are now, but with a safe structure that really will isolate, and won't crush you as it collapses....

So it's not the end of the world. It's just a setback. And you are not the first person to start building a studio, then find out that it is wrong, and need to take it apart again.

Please take some time to read through this thread. The situation is very similar to yours!

viewtopic.php?f=2&t=17363

It's a long thread, but very educational. Hopefully you will do what he did.
Quote:
I felt like I was bothering you and asking too much,
Not at all! That's the reason why this forum is here! Sometimes it takes a long time until I can reply to a thread, because there are many, many people on many active threads, all the time... but if you are desperate you can always contact me by PM (Private Message) and ask me to look at your thread again.

The bad news is that you made a mistake. The good news is that you can fix it easily!

- Stuart -


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PostPosted: Mon Nov 20, 2017 8:34 am 
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It's now been six months since my last (unanswered) post in this thread, so I'm wondering what happened in the end....

- Stuart -

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