So the walls that I keep adjusting in my SketchUp layout would purely be sound treatment walls that are full of exposed 703 with no drywall on either side of them.
Sorry, but I don't understand the purpose of that at all! And in that case, I also do not see where your isolation system is... This is making less and less sense as we go along!
The "square" exterior walls will be 2x6 staggered stud walls with two layers of 5/8" drywall and green glue between each layer. That single wall will be my two leaf system.
I think you should try to actually model that in 3D, with studs and drywall, so you can see for yourself why it won't work...

It is impossible to build what you are trying to build, in the way you are showing it right now. Work it through, to see why... And do consider that you need to have the inner-leaf of each room properly decoupled from the outer leaf, AND ALSO decoupled from the other room...
And also consider that staggered stud walls offer much less isolation than proper 2-leaf MSM walls...
Here's how you should be building it:
MSM-two-leaf-WallChunk-conventional--inside-out--three-rooms--S04.png
That shows a typical situation where there's a large space, such as an unfinished basement for example (the perimeter wall around the whole thing), and part of it needs to be turned into a studio, while the other part does not. In this case, the section on the left will not be part of the studio, and the three rooms on the right ARE the studio. Take a close look: there's a single outer-leaf that surrounds all three rooms, and each room is built as a single leaf that is completely decoupled from the outer leaf, and also completely decoupled form the other rooms. If you start at any point, in any of those rooms, you will find that there are exactly two leaves between that location and any other adjacent room. Never one leaf, never three leaves: only two. It is also dead easy to build, and in this case, all three rooms are built "inside-out", so treatment is also dead easy, WITHOUT requiring extra strangely angled frames filled with even more insulation...
This is the way studios are normally built. It's the most effective, simplest, lowest cost method, and it minimizes construction materials and complexity, while maximizing room volume and isolation. Win-win-win-win.
Again, the "angled" walls I'm drawing it will be my treatment walls which I was hoping to cover in Guilford of Maine and create that super dead space that you said you like to start off with.
Again, those angled walls are totally unnecessary, ineffective, costly, and complex!
Again, if you simply build your inner-leaf walls "inside-out", as shown above, then you already have insulation-filled surfaces facing the entire room! Why would you then want to add yet another "wall that is not a wall", to do the same thing that is already there?
And what is the purpose of angling such a "wall", when the angles would have no effect on anything? Angled walls are only useful when they have hard, solid, rigid, massive surfaces on them, that actually can reflect sound in useful directions. A "wall" made of pure insulation, with no mass, no rigidity, no solidity, and no hardness, is not going to reflect anything, so why would you go to all the hassle of angling it?
In other words, there is zero purpose to your inner angled walls. They accomplish nothing at all, at great expense, and high complexity, and they also completely prevent you from applying solutions such as slot walls or perforated panel treatment, since those require sealed cavities at the back, and with your plan it is impossible to have a sealed cavity...
Then add strips of wood to it (with your advice) to tune the room.
In other words: add a slot wall. But that will not (and cannot) work in your system, because slot walls are tuned resonant devices, based on the Helmholtz resonator principle. In order for that to work, you MUST have a sealed cavity behind the wood slats... but that's impossible with your system. If you tried to create a sealed cavity by adding drywall or plywood to the back of the "treatment wall" studs, that would create a 3-leaf wall, thus negating your isolation...
You are not thinking this through properly . . .
Having said all of that, is my 3rd design on the right track?
No. Because it is based on fall assumptions.
I do not know what frequency I'm tuning the MSM dual door to.

Then how do you know if you are isolating your room correctly? If your MSM frequency is too high (for example, the lowest frequency you need to isolate is less than 1.414 times the MSM resonant frequency), then the system will not only fail to isolate, but in fact will AMPLIFY sounds going through the wall. So for example, let's say that you just took a wild guess at the air gap and mass, and it turns out that your MSM frequency is 34 Hz. Considering that 6-string bass can get down to about 36 Hz, and that's just 1.058 times the MSM frequency, your wall will actually amplify those bass notes: they will be louder on the outside than if you had no wall at all...
It's important to do the math!
If you don't do the math, and just sort of select your air cavity size, damping, and leaf mass by luck and chance, then it's rather likely that the wall won't perform the way you hoped it would, and you'll end up with isolation issues, and treatment issues too.
Studio design doesn't work out to well if you just guess at things: you really should take the time to understand the principles, and do the math. After you've designed and built a few dozen studios like this, you start to get a feeling for how things will work out, and you can skip a few steps in the process for most cases, but when you first start out, it's important to actually work through the complete design process, doing all the math along the way, to make sure it really will work.
All I know is that to maximize the TL between two doors is to have them as far apart from one another as possible.
Ummm... well, yes... that's true... but "maximize" relative to what? That's like saying "All I know is that to maximize the distance I can drive on a tank of fuel, I have to drive slowly... but "slowly" relative to what? And "maximize distance" relative to what? Unless you have done the math, and know that when you slow down from 70 MPH to 30 MPH, you can drive 327 miles on a tank instead of just 270, and you need to go 305 on this trip, then your statement is meaningless and pointless! You can0t guess: You have to KNOW what the numbers are.
Saying that you need to have an air gap "as large as possible" means nothing, unless you know what the minimum sized air gap is that you NEED for your case. Let's say that in reality you need an 8" air gap, but you don't know that because you didn't check, and instead you decide to "maximize" it to 6 inches, because that sounds about right for you... well, that means you screwed your isolation! The wall wont isolate. On the other hand, if you maximized to 8", but really only needed 6" to get the isolation that you need, then you wasted 2" of space....
Do the math, to find out if your "maximized" is enough, or too much, or just right.
I will try and seal/make the sound lock space between the doors a part of the drywalled wall system.
Ummm. you do NOT want to seal the space between the doors! That would be a mistake. That is part of yoru MSM system, so that gap between the doors MUST be open to the gap between the walls. Sealing it would create a separate resonant system, which would probably behave somthing like an undamped membrane trap...
As for HVAC silencers, I was planning on having the HVAC "soffit" (I believe that's what it's called in the forums) around the ceiling on the rear half of the room).
I'm not sure what you are referring to. Do you have a link to that?
Here's a selection of silencer boxes built by forum members:
http://www.johnlsayers.com/phpBB2/viewt ... 0&start=45
http://www.johnlsayers.com/phpBB2/viewt ... 9&start=74
http://www.johnlsayers.com/phpBB2/viewt ... 25&start=2
http://www.johnlsayers.com/phpBB2/viewt ... 42&start=5
http://www.johnlsayers.com/phpBB2/viewt ... 61&start=0
http://www.johnlsayers.com/phpBB2/viewt ... 5&start=98
http://www.johnlsayers.com/phpBB2/viewt ... &start=157
http://www.johnlsayers.com/phpBB2/viewt ... =2&t=13821
http://www.johnlsayers.com/phpBB2/viewt ... 8&start=44
http://www.johnlsayers.com/phpBB2/viewt ... 2&start=16
But here too, you MUST to the math, to make sure the silencer box will do two things: 1) Allow the correct volume of air to flow through at the correct speed, and 2) produce the correct amount of insertion loss at the correct frequencies, to match the rest of the isolation system.
I'd like to have the warm air coming out more at ground level and have the cold air return registers up high.... so I have to figure that out still.
Ummmm... I hope you plan to build your studio inside the ISS Space station then! Because down here on planet earth, warm air RISES and cold sire DESCENDS

So the place where you wanted to "remove the cold air up high", would actually remove your WARM air...
You need to think this through better, and do some research on how air behaves, and how to design HVAC systems.
Lastly, should I start off having the couch riser filled with sand and if the room sucks and needs more bass trapping, I'll have you help me tune it into a bass trap later on?
That sounds to me like you are wanting to design your room by guesswork, and try to fix it later if it doesn't work!

It is far, far better to design it from the start so that it WILL work, then just fine tune the details after it is built.
I'm not sure if you have ever built a sand-filled deck before, but I should warn you that it is a messy thing: the sand goes everywhere, mostly into places where you did not want it to go. And it leaks out: You can try your best to stop it, but it is massive, and it is "loose fill", and it compacts under vibration, and it can fit through very tiny gaps... unless you seal every last nook and cranny, gap and crack, you'll forever be chasing grains of sand around your room. Then if it does NOT work the way you expected,.... well then, good luck with trying to remove a few tons of sand, and leave the room spotless afterwards!
This is not a good plan. Either build it as sand-filled, totally sealed, and leave it like that forever. Or don't build it as sand-filled, and tune it from the start. Trying to do a major change like that "in case it doesn't work" is not a good idea. It's guessing and hoping, instead of calculating and designing.
Of course, so far I'm assuming that you want your control room to be top-notch, well isolated, and as neutral as possible for its size and shape, meeting the specs for critical listening rooms as closely as possible. If that isn't the case, and you are fine with just having it tuned any old way that it happens to turn out, then you don't need to take these precautions, and plan in detail!

But from what you are doing so far, it seems that you really do want it to be as good as it possibly can!
Thanks again for all of your advice Stuart. I look forward to working with you on the fine details once I get basic treatment room shapes sorted out
Here too that sort of sounds like you want an insurance policy! In case your random, non-calculated, guesswork design doesn0't work out, you want to have somebody on hand to fix it afterwards?
Sorry to be harsh, but sometimes it's good to have a bucket of water thrown in your face, to get your attention...
I'd really, really suggest that you should get a couple of books, and work your way through them slowly and carefully, until you fully understand the basics of acoustic theory, and the basics of studio design. The two books I normally recommend, are: "Master Handbook of Acoustics" ("MHoA") 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 background in acoustics that you need to be able to design a studio, and the second one will give you the basics for actually designing it and building it. Realistically, for someone in your situation, it takes about three months of working through "MHoA" and doing the related research, until it starts to make sense, then another couple of months working through "Rod's book", until you get the hang of that, then maybe 3 to 6 months of actual design in SketchUp, with the help of forum members to guide you around the rough spots.
THEN you can start building. So allow for at least 6 months to a year, starting now, until you'll be ready to build.
Hope you don't think I'm trying to put you down, or insult you, or put you off trying to do this!! Not at all: I'm just trying to get your attention, pointing out the issues that you have not noticed, so you can get on the right path and end up with a great studio!
- Stuart -