Early planning, double stud 2 leaf vs. single stud decouple?

I've been researching on these forums for a while now and I think it's time for my first post! (So please bare with me!) First off I'd like to say how awesome everyone on this forum is because I've gotten so many questions answered from you all helping someone else. :D So we're getting a new house, moving from California to Texas, and the house has a game room and a good sized extra room with 9ft ceilings that will become my recording studio. It's so early on I can't give full dimensions of the room layouts, the builder didn't even have a blueprint with the specs for me so they hand wrote the main dimensions. I'm going to be posting more on this forum once I have all the required info that I've been unable to receive so far, but this post is just to figure out the plans with my walls. (I'm definitely looking for input on how I should build my studio all the way up to layout and design.) So my main question is; What would be better for me? Correct me on anything I've mistaken please. :) METHOD 1 - Decouple the inside layer of drywall (5/8ths or 1/2?) and GG + DD? All walls and ceilings. (Also I've read on here that cotton insolation > fiberglass?) So DW > Stud with cotton insolation > Decoupled air gap > DD w/ GG? (I am also assuming 5/8ths? Correct me if this is wrong please.) METHOD 2 - Double stud Decouple method, also with GG+ DD. So DW > Stud with cotton insolation > air gap > Stud with cotton insolation > DD w/ GG? My main concern with doing this method is I don't see how I could do this with the ceilings since they are only 9ft. *Maybe method 2 on all the walls and method 1 on the ceilings? Has anyone done this? Also, I'm COMPLETELY CLUELESS with what to do with the floor, since this is on the 2nd story. I will include a picture of what this area is going to be above. As far as budget goes, I understand something like this can cost anything, but I want to say if I DIY most of it, I want too get it done for 10k, with acoustic treatment included, but that's after the soundproofing. Is this realistic? Anyone have statistical costs on DIY and hiring for these methods for my sq. ft.? (Dimensions showed below) I greatly appreciate any help or info you guys can suggest to me. From here on is the info of my studio and what I require of it. The space that will be available for use as a studio will be the "game room" and "bedroom 5" including the closets. This space is on the 2nd floor only located above the 2 car garage. So the game room will be the control room and bedroom 5 will be the tracking/live room. (Game room will be enclosed) I also think I could utilize the closets to make a vocal both, and cab iso both, but maybe turn the 2 closets into a single larger one with one door leading in through the tracking room for better iso capabilities. Game room: 11' 7" x 20' 5" - 9ft ceilings Bedroom 5: 10' 3" x 16' - 9ft ceilings Here is what this area will above Here are the hand-written dimensions... - I wish I knew more!!! The outside wall of the tracking room is facing the street and is coated in brick on the outside (no idea if it's real brick or more for looks) and I'm mainly worried about sound going out from in. Im very early on in my career but currently specialize in doing heavier, more progressive drum driven music. That can change, maybe I'll start doing tons of country and rock, but I love recording any and all genres and want to be well equipped against even the loudest drum playing, guitar re-amping, etc. Not only because of the fact I will have neighbors, but sound proofed well against my control room as well as the rest of the house. I would like my console facing the window in the game room, though it will be getting covered up, with a window on the side wall looking into the tracking room. There is also a window in the tracking room on the front of the house facing the street, as well as a door going outside onto a balcony (Direct opposite wall of the closet) So once again about the budget, I'm not some rich man. In fact, I'm 18 years old, will be living with my parents and sister until they move out and I buy the house from them or move on, but will have a dedicated income to fuel the needs to build my studio, and earn a living doing what I love and do best. I don't have a mortgage, rent, car payment, or really any type of bill other than a local gym membership. So this is where I tell you, I'm willing to work and save up a little longer to spend 15k and do it right than to cheat myself by spending 10k and regret not doing it differently. There it is. My plan to build my own dream studio. (I've already helped build someone else's - Vividtone recording, CA) I want to have it 100% done within a year of me moving there, which would be by October 2014. I hope by getting this early of a start on receiving ideas and input from all of you, that I will be the only musician and producer of my age that owns an as professional grade studio as this one that any professional audio engineer would kill for! Looking forward to responses! - Braedennn :D

Here is a VERY ROUGH design I did to show the builder what something like this is. Will know in a few days if they can do this while they build the house, or if I will have to bring in an outside contracting company during the build. (I already found a company that has experience in this sound proofing method and will be willing to come in during the build if approved by the builder, that is if the builder can't.) Orange = Doors Blue = windows

Hi Braedennn, and welcome! Please read the forum rules for posting (click here). You seem to be missing a couple of things! :) - Stuart -

Soundman2020 wrote:

Hi Braedennn, and welcome! Please read the forum rules for posting (click here). You seem to be missing a couple of things! :) - Stuart -

John messaged me too and I JUST REALIZED even triple checking these rules that I however DID NOT set my location and I'm completely lost on how to add it!!

Braedennn wrote:

Soundman2020 wrote:

Hi Braedennn, and welcome! Please read the forum rules for posting (click here). You seem to be missing a couple of things! :) - Stuart -

John messaged me too and I JUST REALIZED even triple checking these rules that I however DID NOT set my location and I'm completely lost on how to add it!!

I just found it >.< IT WAS THERE THE WHOLE TIME! I went through all the user control panels and was looking for a drop down tab this entire time....

I just found it >.< IT WAS THERE THE WHOLE TIME!

:shock: :thu: But don't feel bad: lots of people seem to have trouble finding it. I think I'll update the rules to make it more clear how to do that. So, on to your build!

good sized extra room with 9ft ceilings

Nice! That extra foot of height is very useful, acoustically.

the builder didn't even have a blueprint with the specs

That sounds like the place isn't even built yet? About to get started on the build? If so, is there any chance that things could be modified in the actual house build, to make your life easier making that room into a studio?

METHOD 1 - Decouple the inside layer of drywall (5/8ths or 1/2?) and GG + DD?

Not sure what you mean by "DD", but don't use 1/2" drywall: only 5/8". Also, you say "Decouple the inside layer of drywall", but you don't say how you plan to decouple it. There are different methods...

(Also I've read on here that cotton insolation > fiberglass?)

Perhaps, but there's not a lot of data out there on that. The vast majority of laboratory testing that I'm aware of is done with either fiberglass or mineral wool, and they are both rather well understood these days. So unless you have access to a lot of acoustic test data on cotton insulation, its probably better to stick to "tried and true" materials that are known to work well.

(I am also assuming 5/8ths? Correct me if this is wrong please.)

Correct: only 5/8.

METHOD 2 - Double stud Decouple method, also with GG+ DD. So DW > Stud with cotton insolation > air gap > Stud with cotton insolation > DD w/ GG?

Decoupling with double studs is, indeed, the best method, and provides the greatest isolation. Depending on your needs (how many decibels of isolation do you need?), you might need a second layers of 5/8" on each leaf.

My main concern with doing this method is I don't see how I could do this with the ceilings since they are only 9ft.

Depending on how that ceiling is framed, and what else is up there, you might be able to lose as little as a couple of inches. There are techniques for doing that, provided that the existing part is done suitably. That's one of the reasons I asked if the place has not yet been built: its a piece of cake to modify that in the design stage, or while building, and a huge pain to modify it after it is already built. BUt worst case, you'll lose about 5 to 6 inches, so your final inner-leaf ceiling will end up no lower than about 8'6", which is still pretty good. Many home studio builders start out with 7' ceilings... :shock: those are the guys who have real trouble, trying to save every last 1/16"...

*Maybe method 2 on all the walls and method 1 on the ceilings? Has anyone done this?

I'm sure they have, but the overall end result would be the same as if they had just done the entire place as method 1. The effort and money spent on method 2 would have been wasted. Sound is like water: it takes the easiest path out of the room, and ignores all the hard paths. So if the weakest link is the ceiling, that's the way it will get out. In other words, all sides of the room have to be done to the same level of isolation. Including doors, windows, HVAC and electrical.

Also, I'm COMPLETELY CLUELESS with what to do with the floor, since this is on the 2nd story.

:shock: Oops. Depending on how much isolation you need, that could be a problem. You need to put a number on that: get a sound level meter, and do some tests to find out how much you need, in terms of decibels. Building on the second floor introduces a whole new set of problems that you just don't have when you build at ground level, slab-on-grade.

As far as budget goes, I understand something like this can cost anything, but I want to say if I DIY most of it, I want too get it done for 10k, with acoustic treatment included, but that's after the soundproofing. Is this realistic? Anyone have statistical costs on DIY and hiring for these methods for my sq. ft.? (Dimensions showed below)

Ask your contractor how much he would charge to take a typical unfinished double-garage, and turn that into a home theater, family room, or extra bedroom suite. That's about how much this will cost you, in real terms.

The space that will be available for use as a studio will be the "game room" and "bedroom 5" including the closets.

Can all of those interior walls be removed, or are any of them structural (load-bearing)?

So the game room will be the control room and bedroom 5 will be the tracking/live room.

That implies that the musicians will have to go back and forth through the control room for load-in, load-out, bathroom breaks, to answer the phone, or for any other reason. That can add up to a lot of traffic though the CR, plus the hassle of lugging equipment and instruments through multiple doors.... It might be better to re-think that, so each room has a separate entrance, or worst case that the CR is on the far side of the LR.

The outside wall of the tracking room is facing the street and is coated in brick on the outside (no idea if it's real brick or more for looks)

It is important to find out!

and I'm mainly worried about sound going out from in.

You also need to pick up a copy of the local noise regulations from your municipality, in order to find out what your legal requirements are, in terms of how quiet you have to be to not disturb the neighbors, or at least to not have the cops knocking on your door...

and want to be well equipped against even the loudest drum playing,

You probably don't want to hear this, but you are setting yourself up for disappointment if you plan to track live acoustic drums late at night on the second floor of a house in a residential neighborhood, on a very limited budget. Drums are the hardest of all instruments to isolate anyway, even under the best of conditions (ground floor, slab on grade, etc.), but second floor makes it harder still. Drums put out a huge amount of energy in low frequencies, and those are the toughest ones to isolate. Drums are also the loudest of all instruments. There are things you can do to attenuate them somewhat, but each additional decibel of isolation costs more than the last one as you try to get more and more. dB is a logarithmic scale anyway, so the math is not heartening. A typical house wall isolates to around 30 dB, realistically. Improving that to 40 dB is relatively simple, sinve you only have to block ten times as much power. But making it 50 dB means blocking one hundred times as much power, and making it 60 dB means blocking one those times as much. 70 dB is ten thousand times as much.... I think you see the issue here. Drums can easily put out 115 dB, and more. Most residential noise regs insist on levels below 45 dB at night: Do the math, and see how much isolation you need in order to get 115 down to 45. That's a tall order even for room built on a really good concrete slab on the ground. But for a second-story room, on a typical joist-and-plywood floor, that's a really tough proposition. So I would first measure how loud your typical session is, using a sound level meter, then check that against how quiet you need to be, legally. Subtract B from A, and the answer is how many dB of isolation you need. Based on that, you can look at the documentation to find a construction method that will get you there, but there aren't many possibilities for such high levels of isolation on the second floor, and they all cost money to implement. Is there any chance you could move the studio down to the garage, and find some place else to keep your cars? Or maybe build something out in the back yard, on its own concrete slab?

I hope by getting this early of a start on receiving ideas and input from all of you, that I will be the only musician and producer of my age that owns an as professional grade studio as this one that any professional audio engineer would kill for!

It's a great goal to have, and you can get there, but I have bad news for you on the record: you wont be the first. :) A guy in Canada that I designed a studio for last year is just putting the finishing touches to his. He started when he was 18, and is now 20. You probably will be too, by the time you get this place finished. But I'm really heartened to see that there are young musicians and engineers who are so dedicated to getting their places designed and built right early on! I wish I would have had that drive way back then, when I was 18!

Looking forward to responses!

One thing you are missing, and it's a biggie, is HVAC. Your room needs it. HVAC is not an optional luxury for a studio: it is a basic necessity. That needs to be incorporated into the design. If the house already has a full HVAC system sized to deal with these rooms, then that's great: you can just tap into it with suitable silencer boxes, ducts, fans, and registers. If not, then you'll need a couple of mini-split systems. You also didn't mention your electrical system, and that's another oft-forgotten part of studio building, so you should look into that too. I hope I haven't discouraged you too much! - Stuart -

That sounds like the place isn't even built yet? About to get started on the build? If so, is there any chance that things could be modified in the actual house build, to make your life easier making that room into a studio?

Things can be modified. But I'm only guessing it's to a certain extent, and my parent's aren't wanting to reconstruct the house very much :wink: But maybe remove the closets completely to have a bigger tracking room, per say: if my band want's to use it as a practice room as well!

Not sure what you mean by "DD", but don't use 1/2" drywall: only 5/8". Also, you say "Decouple the inside layer of drywall", but you don't say how you plan to decouple it. There are different methods...

Double Drywall. Method one would be to use Soundproofing Clips and Drywall Furring Channel (Hat Channel / Track) compared to method 2 being double stud. - but then again I'm thinking it may be better to just use the best insulation method I can for my control room, and go all out on the live room.

Perhaps, but there's not a lot of data out there on that. The vast majority of laboratory testing that I'm aware of is done with either fiberglass or mineral wool, and they are both rather well understood these days. So unless you have access to a lot of acoustic test data on cotton insulation, its probably better to stick to "tried and true" materials that are known to work well.

I've worked with mineral wool a lot for constructing bass traps, and other room treatment items, I'm still new here so I'm not sure if I can't post links or anything like that so correct me if I can't and I'll take it down but what out of these would be best for insulating the walls for the best transmission lost? - http://www.atsacoustics.com/cat--Fiberg ... --106.html

Decoupling with double studs is, indeed, the best method, and provides the greatest isolation. Depending on your needs (how many decibels of isolation do you need?), you might need a second layers of 5/8" on each leaf.

I am now thinking that decoupling with double stud for my control room may be unnecessary, but for my live room, I want to keep my family, neighbors, somewhat happy (and obviously legal) with live acoustic drums. I can only record drums during the day. And I was planning on doing a second layer of 5/8s with green glue.

BUt worst case, you'll lose about 5 to 6 inches

Well if I do any double stud, the ceiling will definitely be done as well.

all sides of the room have to be done to the same level of isolation. Including doors, windows, HVAC and electrical.

Putting it like that makes me understand this better :D I now know how to explain it to the builder without him thinking I'm weird.

Can all of those interior walls be removed, or are any of them structural (load-bearing)?

I will have to find this out. If they can, I'd like to change some things, and I don't see how the bedroom wall is load-bearing. I came up with a rough drawing of a way better design, If you'd like too see it I can post it. Maybe you'll tell me "Don't do anything unless you can do that" or you might just way "things will work out fine the way they are, but to remove the closets and double stud and double drywall the live room and have everything insulated with mineral wool." Let me know if you want to see it.

That implies that the musicians will have to go back and forth through the control room for load-in, load-out, bathroom breaks, to answer the phone, or for any other reason. That can add up to a lot of traffic though the CR, plus the hassle of lugging equipment and instruments through multiple doors.... It might be better to re-think that, so each room has a separate entrance, or worst case that the CR is on the far side of the LR.

My other rough design I did is a airlock into the tracking room, which is very non-paralell shape, with an airlock into the control room which is a "coffin" shape. The airlocks wont be large, just inches apart. Like I said if this interests you I will reply with the picture and you can tell me if its a great idea or not.

It is important to find out!

I will find this out as soon as I can then!

You also need to pick up a copy of the local noise regulations from your municipality, in order to find out what your legal requirements are, in terms of how quiet you have to be to not disturb the neighbors, or at least to not have the cops knocking on your door...

I will find this out as well.

You probably don't want to hear this, but you are setting yourself up for disappointment if you plan to track live acoustic drums late at night on the second floor of a house in a residential neighborhood, on a very limited budget.

It doesn't need to be late at night. But if I have a full production album to record, it's going to be a week of drums 8 hours a day! So again nothing super loud will be late at night, but I want the sound of a drum set from outside of the house to be reasonable. Also thank you for explaining how improving the dB works I'll have to study this more so I can figure out what I require.

So I would first measure how loud your typical session is, using a sound level meter, then check that against how quiet you need to be, legally.

My current typical sessions are very quiet, considering I can't do live drums in my current studio (due to the lack of space and sound proofing) I program most my drums, which turn TONS of potential clients away. My solution to this WAS going to be to buy pearl TruTrac heads and basically turn an acoustic set into a highly accuractely triggered electric kit. But this would still be a turn off to many drummers. So the goal is to do a full live acoustic drum set. Even have a full band practice and still not have complaints from neighbors.

Is there any chance you could move the studio down to the garage, and find some place else to keep your cars? Or maybe build something out in the back yard, on its own concrete slab?

No way :( but in 5 years from now I will be getting my own house and be able to plan everything else around the studio, instead of the studio around everything else.

But I'm really heartened to see that there are young musicians and engineers who are so dedicated to getting their places designed and built right early on!

This is my life :D Wouldn't ask for it to be any other way either!!

One thing you are missing, and it's a biggie, is HVAC. Your room needs it. HVAC is not an optional luxury for a studio: it is a basic necessity.

I am very aware about this. I've been doing more research on these, as well as trying to convince my parents to use ductless HVAC systems throughout the entire house! They can put a room at any temperature you want it and to my understanding the savings for cooling/heating compared to a normal house air conditioner, which controls the temp of the whole house, would well pay for itself very fast. Would you agree? Also I've come across "portable" air conditioning units, specifically this one - https://www.goductless.com/LG/LP1411SHR ... 22&subCat= Would you be completely against something like that?

You also didn't mention your electrical system, and that's another oft-forgotten part of studio building, so you should look into that too.

What do I need to find out about my electrical system?

I hope I haven't discouraged you too much!

You've only done the opposite! :D - Braedennn

Incase you didn't see I edited my bump to this and is my first idea for my studio.

Braedennn wrote:

Here is a VERY ROUGH design I did to show the builder what something like this is. Will know in a few days if they can do this while they build the house, or if I will have to bring in an outside contracting company during the build. (I already found a company that has experience in this sound proofing method and will be willing to come in during the build if approved by the builder, that is if the builder can't.)

External image, not preserved — original: http://i1034.photobucket.com/albums/a427/braedenalter/studiorough_zps65e8f7dd.png

Orange = Doors Blue = windows

Bump. its been over 10 days just keeping post alive.

Ooops! Another thread that slipped through the cracks! :oops: In your control room, your doors are where your speakers need to go. The angled parts of the front wall are usually used for speaker "soffits" (flush mounting), so they can't also be doors. I would suggest making the large blue window between the CR and LR into a pair of sliding glass doors, and find another way of getting into the bathroom, so you leave those front angled bits or your speaker soffits.

I'm still new here so I'm not sure if I can't post links or anything

Yeah, that's fine: as long as you don't post links for the purpose of promoting or selling stuff, then that's fine. You can also post images of products you are thinking about, if you want. No problems.

what out of these would be best for insulating the walls for the best transmission lost? -

For mineral wool, look for stuff that has a density of roughly 50 kg/m3 (about 3 pcf). Or if you prefer fiberglass, then you need a density of about 30 kg/m3 (2 pcf). On that page you linked to, the absolute best stuff on the list, hands down, no questions asked, is 4" OC-703. That's really good stuff.

And I was planning on doing a second layer of 5/8s with green glue.

That's also a good idea, for better isolation. Definitely.

Would you be completely against something like that?

Yes! Not a good idea. Those things are noisy!!! And then still need an air duct to exhaust hot air out of the room, plus you need to empty the condensation container every hour or two, as it fills up.... Not a practical solution for a studio.

as well as trying to convince my parents to use ductless HVAC systems throughout the entire house!

You still need ducts, especially in a studio. The ductless "mini-split" type HVAC units do a good job of cooling, heating and dehumidifying, but they do not supply any fresh air into the room, an they do not exhaust the stale air. so you still need ducts to do that. There's no way around it, unfortunately. You need to breath in there, and making a room soundproof means that you also made it air-tight, so you wont last long in there without air....

What do I need to find out about my electrical system?

You need to plan where your cabling will run, how you will supply the lights and equipment, star grounding, circuit breakers, switches, dimmers, outlets, etc, plus also for your signal cabling between rooms, etc. All of that has to go through conduit, not like normal house wiring, and with only one penetration per room (OK, one for electrical, and one for signals). Sorry about the delay in replying! :oops: Stuart

Ooops! Another thread that slipped through the cracks! In your control room, your doors are where your speakers need to go. The angled parts of the front wall are usually used for speaker "soffits" (flush mounting), so they can't also be doors. I would suggest making the large blue window between the CR and LR into a pair of sliding glass doors, and find another way of getting into the bathroom, so you leave those front angled bits or your speaker soffits.

It's okay I'm in no rush until september/october! :) This is just the sound isolation for the room, I will be building he room treatment accordingly, the side of the rooms with the doors will be the rear of the room. Planning on supper chunking the front corners and bass trapping the entire front wall, having a couple clouds, angling the front one, thinner bass trapping down the side walls, thicker on the ceilings corners, I will go more in depth later, but right now I'm focusing on isolation, and a few things have changed with my build, as far as what I'm being ALLOWED to do... As far as the soffits, I will be getting some barefoots, which you do not soffit. I'm also considering the sliding glass doors going into the LR. It all depends on price and costs!

For mineral wool, look for stuff that has a density of roughly 50 kg/m3 (about 3 pcf). Or if you prefer fiberglass, then you need a density of about 30 kg/m3 (2 pcf). On that page you linked to, the absolute best stuff on the list, hands down, no questions asked, is 4" OC-703. That's really good stuff

My build changed as far as the fact I can NOT tear down any drywall, and will only be able to build a second wall INSIDE of the LR. The builder would not do this during the build, though they considered it, and my parents want everything to be left normal (to an extent) so that when it comes to selling, we just have to tear down the inner wall in the LR and put some flooring in. But as far as Isolation goes, I really don't need the 2 walls for my CR. Just acoustical treatment, which I'm aloud to do. So considering I can't rip any drywall out and build the second stud wall, and I'm left with having to deal with a 3 leaf wall system, what would be the best approach for this inner wall? Inside out wall? or just follow the same rules besides the fact there IS a 3rd leaf in between the 2 stud walls?

You still need ducts, especially in a studio. The ductless "mini-split" type HVAC units do a good job of cooling, heating and dehumidifying, but they do not supply any fresh air into the room, an they do not exhaust the stale air. so you still need ducts to do that. There's no way around it, unfortunately. You need to breath in there, and making a room soundproof means that you also made it air-tight, so you wont last long in there without air....

I am getting a mini split system, and the house's central air and heat is remaining in tact, and will be extended into the live room's second stud wall once it's up.

You need to plan where your cabling will run, how you will supply the lights and equipment, star grounding, circuit breakers, switches, dimmers, outlets, etc, plus also for your signal cabling between rooms, etc. All of that has to go through conduit, not like normal house wiring, and with only one penetration per room (OK, one for electrical, and one for signals).

I want to run with a track light system in each room, which from my experience with extending and re-shaping them it seems like the best way too go, just have to have an electrician wire the stuff for it. I'm using a simple "hole through the walls" method as far as snakes and cables go, but it will go through the closet first, and then out the closet into the LR so there wont be drums blasting through any holes. As far as the conduit goes I'm going to hire someone to install the hvac system, as well as an electrician to put all the lighting and outlets needed for my inner wall of the LR, but for my CR the house's standard outlets do just fine through a few battery backups and power conditioners.

Sorry about the delay in replying!

its no big deal! :) just felt very forgotten! :( Thank you for your time and input and questions I should be asking myself :) I value everything I learn from you or anyone else on here!

This is just the sound isolation for the room, I will be building he room treatment accordingly,

Right, but they still need to be designed together. If, during the isolation planning, you cut off parts of the room that are critical for treatment, then you are pretty much up the proverbial creek without the proverbial paddle...

the side of the rooms with the doors will be the rear of the room.

Then you have cut off the area where your bass trapping needs to go! The rear vertical corners are among the best places in the room for bass trapping, and since it is a small room it is going to need a LOT of bass trapping...

Planning on supper chunking the front corners and bass trapping the entire front wall,

That's kind of backwards for the way most rooms are designed these days. That's more along the lines of the 30-year old LEDE concept, which has been pretty much abandoned these days: Too fatiguing, unnatural, etc.

thinner bass trapping down the side walls

Bass trapping on the side walls is pretty ineffective, considering that the modal nodes are in the corners, and the nulls are on the walls. If you wanted to trap along the walls, then it would have to be pressure based devices, such as membrane traps. Also, "thin" and "bass trap" do not go together.... The frequencies where room modes are problematic correspond to very long wavelengths, on the order of tens of feet, so bass trapping has to be substantial.

As far as the soffits, I will be getting some barefoots, which you do not soffit.

OK, so we are talking about massively heavy stands behind the desk, up against the front wall, 28% width, 1.2m height, 60° intercept for a listening position at 38%?

My build changed as far as the fact I can NOT tear down any drywall, and will only be able to build a second wall INSIDE of the LR.

Ouch! so you are stuck with three-leaf walls then? Pity. That's going to be problematic for high levels of isolation at low frequencies.

what would be the best approach for this inner wall? Inside out wall? or just follow the same rules besides the fact there IS a 3rd leaf in between the 2 stud walls?

For three leaf, the optimum technique is to have equal sized air gaps, and with most of the mass on the middle leaf, such that 2 x M1 = M2 = 2 x M3. So you need about twice as much mass, or twice the air gap, or a combination of both, to get the same isolation. It does not matter which side you put the stud on: MSM is governed only by the mass of the leaves and the distance between them, so the decision on building inside-out or conventionally is purely related to room design concept, use of space, and treatment.

I am getting a mini split system, and the house's central air and heat is remaining in tact, and will be extended into the live room's second stud wall once it's up.

Great, but don't forget to leave enough space for your silencer boxes (for both rooms): they are pretty bulky.

I'm using a simple "hole through the walls" method as far as snakes and cables go, but it will go through the closet first, and then out the closet into the LR so there wont be drums blasting through any holes.

I'd really suggest that you re-think that: If you don't run conduit for your cables they you are pretty much screwed when you need to run more cables in the future, or change something, or repair something. Conduit is dirt cheap, compared with the cost of tearing holes in the wall a few months down the line to add something you forgot... or worse still, doing without something that you need! This is probably the second biggest issue I have run unto with my post production customers over the years: they ALWAYS need to add something else as needs change, and without conduit they end up spending big money to do that. For the sites that I design, without fail I specify everything in conduit, and over-sized conduit. It just makes things so much easier.

As far as the conduit goes I'm going to hire someone to install the hvac system, as well as an electrician to put all the lighting and outlets needed for my inner wall of the LR, but for my CR the house's standard outlets do just fine through a few battery backups and power conditioners.

The conduit is not for the HVAC, or for wiring within the room: it is for getting the cables into the rooms in the first place, and also running them between the rooms. All of the wiring within the room is surface-mount anyway, and a structured cabling system is best for that (if you are building conventionally), or just plain wiring (if you are building inside out). You cannot do conventional sockets, switches and light fittings in a studio, for obvious reasons: surface mount is your only option.

Thank you for your time and input and questions I should be asking myself

That's the great thing about this forum: you have several pairs of eyes looking over your design and build, spotting things that you might not have noticed. - Stuart -