John Sayers' Recording Studio Design Forum Archive

LAST EDIT on 9/15/2016 at 7PM PST
Hello,
I've cleaned up my post quite bit -- hoping it's more clear now. Apologies for changing it so much - I'm still scratching my way up the learning curve. This forum throws new info at me around every corner! I will try to stop editing until i get a reply . Sending my gratitude to all the posters here. It's really generous of you to help folks with their projects.

My name is Cliff Parker. I work in video production and I live in San Francisco, CA.

Here is a link to my Sketchup file if you want to dive right in.
CP VID STUDIO PLAN

Otherwise, there are stills for folks to look at throughout the post.
Here we go!

PRIMARY USES:
- Video Editing

SECONDARY USES:
- Electronic Music Production
- Voice Over Recording

PRIMARY GOAL:
- Eliminate, or significantly lessen the noise from upstairs foot traffic, voices, kids playing, etc.
- Create a clean dust-free environment.

SECONDARY GOAL:
- Reduce the sound I create from being heard upstairs.

LOCATION INFO:
The space I intend to build is in the back corner of a ground floor 1-car garage in a stand alone house. 33'L x 28'W is the approximate area of the entire garage/ground floor. The garage is roughly 33'L x 14'W -- it's half the ground floor. Other half is storage (with a lot of shit)/water heater/furnace. It is a carriage house, so its set back from the street about 100’. Surounding properties are backyards on 3 sides, driveway to my house is the 4th side. Two adults, one of them is me, and two children live above the garage/ground floor.

EXISTING CONSTRUCTION: The floor in the garage is concrete (thickness unknown) on earth.
Base of walls from floor up are 8” brick. On top of that is 4 ¾” high wood footer.
Walls are 5 ½” thick – Interior is ¾” Plywood, Exterior is ¾” siding. Real 2x4 studs! Its an old structure. No insulation in these walls.
Ceiling is ¾” Pine tongue & groove subflooring on top of 2 x 8 exposed joists.
Height from concrete floor to exposed floor joists is 88”.
Flooring above tongue & groove subfloor is ½” hardwood floors.

LABOR:
I have built furniture as a hobby (and at times professionally) for about a decade, so I plan to do all the work myself, including building a custom desk, door, and traps if they are needed. I have a full wood shop in my garage (hence the reason for a dust-free environment), and a lot of existing building materials. I can also tap into the existing electric without any trouble - I'll only need a few outlets that will be surface mounted. And I'm thinking about using LED lights that plug into an outlet.

HVAC
I'm just beginning to read about HVAC and soundproofing. Although it seems complicated, creating the correct air flow system in this space seems doable from what I've read so far. There's certainly a ton of info on the subject in this forum. So I will cross the HVAC bridge once get clarity on a few key details of my plan.

BUILDING MATERAL BUDGET:
Not exactly sure. I’d be willing to spend up to 6K if I feel confident about a design that will get me close to my goals.

SPEAKERS:
I own a pair of Adam Audio P11A Active Studio Monitors. I’d like to use these, but I have a sense that they may be too big for the space I intend to build - but not certain.

DILEMMA 1:
SMALL SPACE Due to existing construction and space usage, the yellow area in the above floor plan is the maximum space I have to build in the garage. I have stretched every last inch possible. I am only beginning to understand the long list of limitations a room this size could have. If I am understanding room ratios correctly, the ratio of this space (1.42:1.02:1 according to Amroc Calculator) would be one to avoid. Is this correct?

Despite it’s small area, and bad proportions, it is enough physical space for my needs. That said, I'm getting more and more perplexed about how well it will work because of the small room size. As in, "maybe I'm trying to create a space that will cause more or newer problems than I have now". With my goals and budget in mind, would the ratio of this space be enough to scrap the idea from the gate? (If the answer is yes, I've clearly done too much planning ). Or can construction techniques/room treatment/other tricks get me to my goal despite the unfavorable ratio? (if the answer is yes, or even maybe, please read on )

DILEMMA 2:
I CAN HEAR EVERYTHING UPSTAIRS!!! Even quiet conversations. (Interestingly enough, people upstairs can barely hear me when I yell up to them to quiet down! why is that?). When no one is home, or when people are sleeping, the garage is actually incredibly quiet as is. And I get very little constant exterior noise. Airplanes, UPS trucks, Harleys, etc., yes of course come blaring through, but not constantly. I have done voice over recordings in here for several years, and the sound quality is good. Also, I don’t do a ton of recording. I’m really just trying to cut down the noise from upstairs and create a quieter space to edit video. But when the family is home, the noise level is just too overpowering. Here are some db readings of most bothersome noises that come from upstairs. Hope I did these right . I took all the above readings from the mix position, as I yelled up stairs for kids to make noises. It was kind of fun. The first two I took when no one was home. Distance figures without inches are rough estimates, but close.][/b]

Next is the noise I make. For the test in the table below, I set up my speakers as close as I could as shown in the Sketchup file. I was playing a combo of Wyclef Reggaeton tracks and an Abelton tutorial video about room tuning on youtube -- just some dude talking. Again, distance figures without inches are rough estimates, but close. So based on these figures, it seems to me that a sensible target for my isolation needs would fall between 50-60db. Is that accurate? I can easily glue some felt to the bottom of the stools legs - this was the loudest noise from upstairs. As for the other noises that hit up around 70db, these happen less frequently. And if I could get 50-60db of isolation, I would assume, these noises would be far less bothersome even when they do occur. It also seems to be a reasonable target for isolating the noise I make from traveling upstairs. Not perfect, but a lot quieter than now. Plus, I rarely turn up the volume as loud as I had it during these tests. Perhaps I can drop the amount of isolation to 45-50db?

DESIGN DETAILS & QUESTIONS:
Below are the design details that I am not completely sure about, as well as a more detailed approach of how I plan to build the room. Apologies if some of this falls under "Studio Construction." But answers to the below questions will help me finalize my design, so I thought I should included them. If I'm off base here, let me know and I will happily move construction questions to the correct forum.

EXISTING SPACE: I am unsure about finishing the existing walls and joists here for a couple of reasons. First, due to existing construction & space usage in my garage/ground floor, I am only able to finish the walls and joists that are highlighted above in blue, continuing to the back corner (just in the area of my intended build - shown in yellow). The rest of the walls and joists in the 33' x 28' garage/ground floor would remain untreated.

Second, since noise coming from outside the house is not my primary concern, I would only consider insulating/sheet rocking plywood walls and joists if it cut down the overall noise traveling down from the upstairs. I have read that this is not the most effective way achieve isolation, particularly with the joists. Is that correct? Also, If the room I build has it's own ceiling, separated from the above joists, Is there any reason for me to consider insulating/sheet rocking the existing walls and/or joists shown above in blue?

That window goes to my neighbor's back yard -- I don't want to cover it.

INTENDED BUILD EXTERIOR: This is the exterior of the room I intend to build. The vertical dimension (7' 2 ¾") is the height of the room exterior. There is a 1 ¼" space between the ceiling and the floor joists. Should I shorten/heighten the walls to make this gap smaller/larger? How close should I go to the joists with the ceiling? That area is prime real estate for HVAC right?

Regarding the two walls closest to the existing plywood walls -- there would be a ¾" space between the base of the studio walls and the existing brick footer. Moving upward, the space between the studio walls and the existing plywood walls would increase to 8 ¼". Do I factor these two walls in when trying to determine how many leafs I have? I am confused here because I don't know if the existing walls are considered leafs since there are only two (and not four)) within close proximity to the studio walls.

Still reading up on doors. I would like to get away with building just one door. (I could be convinced to build two I suppose) My space seems too small for double doors. This is likely going to be a weak spot for my room. If anyone has seen a beefy single door designs, please point me to it.

FLOOR:
After a lot of reading, I think I should anchor the wall base plates directly to the concrete. But the concrete is not level. There are not major holes, but surface varies up to 1 ¼". Is this too great a difference to use concrete leveler, and still anchor the walls down? Are there other methods to leveling the concrete surface? Would neoprene or rubber pads help in this situation? I should say that I don't like jack hammers, and would very much like to avoid having to rent one. So, removing and pouring new concrete is my last resort option.

I plan on laying sheets of ¾" plywood on the concrete for the interior floor.

WALLS:
Due to the space limitations, I felt that staggered 2x4 studs on 2x6 base and top plates would be a good choice. I would insulate these walls. I would use 2 layers of 5/8” sheet rock on the exterior walls of the room. I just read that using Plywood as the first layer of the interior leaf turns the entire wall into a screwing surface. I like that idea! So plywood on first layer, ⅝" sheetrock on top of that for the interior walls. This would be 2 leaf system correct?

On another note, based on the reading I have done, I can't determine if products like Green Glue and Quiet Rock will help my situation. If they will help, I would use them. But I already have a lot of 5/8” sheetrock, and would hate to have to go out and spend more $ if it won't help.

I plan on finishing exterior leafs of the two studio walls that will be closest to the existing walls, on the ground, then standing them up.

Last point on the wall construction -- I realize that all the studs are connected to the base and top plates, unlike a two wall approach with an air gap in between. Still, is it ok for the corner studs that support the interior leaf to laterally connect to the corner studs that support the exterior leaf. I have not yet found an example that staggers the studs around the corners. If the exterior and interior corner studs should not connect in any way, the only option I see is to not screw the walls together at the corner studs. But instead, use the force of the floor anchors and ceiling to tie the walls together. Is this accurate, or am I missing something?

CEILING: The above image is how I plan to do the ceiling frame and exterior. I will insulate between frame members. I used a load limit calculator (not sure if I am allowed to post link) and got a span limit of around 8 feet with this design. I say "around" because the one I used wouldn't let me set the live load to zero. Is it correct that the span of this 2 x 4 ceiling frame will have no live load? I calculated the weight of the ceiling at approximately 1000 lbs - which includes the interior leaf of the ceiling -- I plan to hang two layers of ⅝" sheetrock (or one layer plywood/one layer sheetrock) on the interior ceiling of the room. 2-leaf system right?

I touched on this above in the post - my main question here, is whether I should (1) try to "cap" the room with a ceiling that doesn't touch the floor joists (like the above image), or (2) insulate the joists and hang the sheetrock ceiling from them. Or (3) Both?
As for the back corner bead on the sheetrock, it will be tight (8 ½"), but I can squeeze in there to mud it.

INTERIOR DETAIL 1: Here's an overhead view of my interior space. As you can see, one wall is angled to follow the angle of the existing wall. I did this partly to gain a bit of space (partly cuz I didn't know what to do), but I can lose the angle (it's 5°) and make the room a rectangle easily enough. Does it make sense to keep the wall angled like this? If so, I plan to use it as the back wall of the studio. The 9’ 9 5/8” measurement is the length on the longer side of the interior of the room, 9' 2 13/16" is the shortest length. 6' 9" is the height to the interior drywall ceiling.

INTERIOR DETAIL 2: NOTE: CORRECT CEILING HEIGHT IS 6' 9". CORRECT MIX POSTION HEIGHT IS 48" I WILL UPDATE IMAGE AS SOON AS I CAN
The above stills are regarding speaker placement, and, a subject that I am certainly in the deep end of the pool at the moment (if not drowning), room treatment. The above images show where my plan is at right now. Distance from front the wall to mix position is at 45% of of length of room (I averaged the shortest and longest lengths). So it's too far, right?. The speakers are at a 35° angle. I have seen some post where speakers are angled at 45° and spread out a good deal. Would this be a better option for me? The dilemma here is that I want to mount 2 computer monitors to the front wall, and I need about 45" of space between the speakers inner most corners. (I don't need that much wall space -- monitors will be on articulating arms that are mounted to the wall. Probably need 20" of flat wall space -- 10" each way from the center of the wall for mounting) So every inch counts. If I angled the speakers 5° more (40° total) that would get mix position right around 38%. If that angle is ok, how far does the rear of the speaker need to be away from the wall to build an effective soffit?

At this point I would really like to leave the option open to flush mount the speakers. I have read that doing so in small rooms can be helpful. If that is the case with my room, I would like to do it. I am also open to purchasing new speakers if the P11As are a bad fit for this size room. Should I flush mount? Buy new speakers? Both?

What I've gathered on this site about acoustic treatment, is that performing REW tests after the room is built, is the best way determine an accurate approach to treating a room. However, folks also seem to design a room reserving space for placement of traps and clouds, etc. Perhaps I just need more time to learn, but when I read about acoustic treatment, I keep asking myself the same question: Do I have enough room to add acoustic treatment once it's built?

Some of what I have read leads me to believe that the room is just so dam small, and proportionally flawed, that trying to treat it may be futile. However, since I'm new to this, I gottta believe or hope I'm wrong.

It's funny, walking into this, I was so concerned with eliminating the noise from upstairs, that I never really gave much thought to the fact that I would have a sealed environment to deal with -- that seems to come with a whole new set of challenges. Also - based on my room needs - perhaps I don't need to concern myself with these details so much. But in my quest to create a quieter space I have discovered that there are ways to make a room "soundproof", and then there are ways to make a room sound good. Given my budget and needs, I'de like to achieve the best scenario possible.

So, if my design is anywhere close to copasetic, then perhaps I’m learning from what I’ve read so far. If not, well please tell me to “take it back to the drawing board.” I'll work on it some more and return with something better. Also, I realize this isn't anywhere close to a full blown recording studio, so if it takes back seat to other projects, I understand. Still, I've attempted put some effort into researching my plan (mostly with the help from all the nerd talk in here ) with the hopes of clearly presenting the design and my goals to this community. I hope it does just that!

Thanks for reading, looking and thinking on my behalf. Looking forward to any feed back folks can offer -cp

Hi there Cliff, and Welcome to the forum!

I'm really sorry about the delay in responding: It seems I'm the only moderator on the forum at present, and there's a lot of activity, with many active threads and builds going on.... but there's only one of me! Unfortunately, I'm really busy with several projects at once, so sometimes it takes me a long time to answer a post. I have a list of about 76 posts that I need to reply to, and only a limited amount if time in the day where I can do that.

But anyway:

PRIMARY GOAL:
- Eliminate, or significantly lessen the noise from upstairs foot traffic, voices, kids playing, etc.
...
SECONDARY GOAL:
- Reduce the sound I create from being heard upstairs.

Those are related, but not totally the same. The foot-fall problem is impact noise, which is structure-borne: it runs in the actual building materials of the house, ans is not so easy to deal with. The other two are both air-borne noise, and easier to deal with.

The very best way of dealing with impact noise, is to prevent it from happening at the source: lay thick carpet with good quality underlay on all the floors where you have this foot-fall problem. That is, by far, the easiest and cheapest way to deal with it. If the sound never gets into the structure in the first place, you wont have to spend thousands and thousands of dollars trying to get rid of it. Just cut it off at the source.

The floor in the garage is concrete (thickness unknown) on earth.

Great! Then your floor is already done! Nothing more needed there.

Walls are 5 ½” thick – Interior is ¾” Plywood, Exterior is ¾” siding. Real 2x4 studs! Its an old structure.

Your best bet here is to pull the plywood off the inside, exposing the studs and bays, then "beef up" the outer side by adding mass to it, in the form of strips of drywall, plywood, MDF, OSB, etc. that are carefully cut to fit in between the studs: Caulk the edges to seal it well, use small cleats to hold it in place, and you are done. That's your "outer-leaf" walls.

Ceiling is ¾” Pine tongue & groove subflooring on top of 2 x 8 exposed joists. ... Flooring above tongue & groove subfloor is ½” hardwood floors.

Ditto. Beef it up in the same way. That's your "outer-leaf" ceiling.

Height from concrete floor to exposed floor joists is 88”.

Ouch! That's not so good. You have practically no headroom. Getting good isolation here is going to be a problem.

including building a custom desk, door, and traps if they are needed. I have a full wood shop in my garage

Excellent! You have the skills and the tools. This is very good!

I'll only need a few outlets that will be surface mounted. And I'm thinking about using LED lights that plug into an outlet.

I'm just beginning to read about HVAC and soundproofing. Although it seems complicated, creating the correct air flow system in this space seems doable from what I've read so far.

doing the math and the design can be complicated, yes, but not impossible. You already found the references here on the forum, so once you work through those, and have your basic plan roughed out, post the details so I can take a look.

BUDGET:
Not exactly sure. I’d be willing to spend up to 6K

Probably a bit on the low side, to be honest: Especially if you need to isolate impact noise.

I own a pair of Adam Audio P11A Active Studio Monitors.

Nice! I'm a fan of Adam. Those should work fine.

I have a sense that they may be too big for the space I intend to build - but not certain.

Perhaps, but they should work reasonably well in there, at least to get started. Besides, your budget does not stretch to new speakers, so I would go with those initially, and only change them later once the budget is there.

DILEMMA 1:
SMALL SPACE

Yep. That's less than 90 ft2, and without even considering isolation yet. General recommendation is at least 200 ft for a CR. It is possible to have a decent place in less room, but the smaller it is, the harder it gets.

If I am understanding room ratios correctly, the ratio of this space (1.42:1.02:1 according to Amroc Calculator) would be one to avoid. Is this correct?

I figure your ratio as 1 : 1.11 : 1.43. Not fantastic, but also not terrible. It's on the edge of the Bolt area. A bit too long for the low ceiling, but for such a small room I would rather keep the volume as great as possible, instead of trying to improve the ratio. It's OK.

That said, I'm getting more and more perplexed about how well it will work because of the small room size. As in, "maybe I'm trying to create a space that will cause more or newer problems than I have now"

Small rooms need proportionally more treatment than large rooms. The smaller they are, the more they need. Yours is very small, and will need lots of treatment, but it can still be usable.

With my goals and budget in mind, would the ratio of this space be enough to scrap the idea from the gate?

Not at all! The ratio is not terrible, and you don't need to sweat room ratios overly much in any case. they are just one factor in many that designers use when figuring out how to make a room work.

Or can construction techniques/room treatment/other tricks get me to my goal despite the unfavorable ratio? (if the answer is yes, or even maybe, please read on

I'm still reading... !

(Interestingly enough, people upstairs can barely hear me when I yell up to them to quiet down! why is that?)

Probably due to ambient noise: It's probably reasonably quiet in the garage (apart from the noise coming in from above), so things sound louder. Also, it is likely resonant down there, so people walking on the floor, and even talking, sounds "boomy", which our brains tell is is "louder", even though it might not necessarily be. Compare that to upstairs, where there is likely ambient noise going on that masks sounds coming from down below to a certain extent, plus most houses have a lot of diffusion and absorption in the rooms (furniture, people, decorations, etc.) so much less reverberation. So what you are hearing as a difference in isolation, is probably more of an illusion than a real thing.

When no one is home, or when people are sleeping, the garage is actually incredibly quiet as is.

Bingo! As I suspected. In a quiet area, even quiet sounds appear to be noisy, whereas the exact same sound in a nosier place does not seem to be loud at all. Psycho-acoustics, masking, blah-blah, etc.

Here are some db readings of most bothersome noises that come from upstairs. Hope I did these right

Unfortunately, you measured them with "A" weighting! You should have used "C". "A" is not sensitive to low frequencies, "C" is. So your readings do not take into account part of the sound spectrum. That said, the levels are still very interesting, and very revealing.

Your big problem is impact noise. As I already said, the best, cheapest, most effective solution for that is to just carpet all the floors where it is a problem. Yes, that's expensive to do, but it is actually cheap compared to what you'd need to do to deal with it isolation.

"Very slight hum from fridge"... that, too, is "impact noise". More correctly, it is from mechanical flanking, but still the same principle. Put rubber pads under your fridge feet. If you tell me how heavy your fridge is, I'll tell you what type of rubber and how big to make the pads.

Piano, front door, running, dresser drawer, jumping kid, remote drop, stool sliding... all of those are impact noise. All can be dealt with at the source.

That would leave you with just air-borne sound to deal with, and that's a lot easier... relatively!

Next is the noise I make.

You did that on "C"! Good! much more realistic. A very interesting entry on your table is "exterior 6", out at the curbside: that0s your ambient noise level! Around 70 dBC, which is pretty loud. So inside the house, ditto. That's why they can't hear you so well, but you can hear them. You have an ambient level of 28, they have an ambient level of probably 50 or so. Q.E.D.!

You are also missing one reading on that table: you should always measure the reference level at 3 feet from the sound source: That's the "standard" for acoustic readings. But it's easy to extrapolate that it would have been around 90 dBC.

All of your upstairs readings are peaking at roughly 60. Your sound source was roughly 90. So you ave roughly 30 dB of isolation, for airborne sounds, which is typical of a house.

The question is, how much do you need?

So based on these figures, it seems to me that a sensible target for my isolation needs would fall between 50-60db. Is that accurate?

About right, yes. 60 would be great, but very hard to attain in your situation. 50 would be a reasonable goal, and reachable. Subjectively, it would be 75% quieter down where you are.

I can easily glue some felt to the bottom of the stools legs

That would help for that one single item, but won't do anything for the rest. On the other hand, laying carpet will help for all items, including the stool...

Perhaps I can drop the amount of isolation to 45-50db?

that's a reasonable goal, but I would shoot for 50 rather than 45. You could even shoot for 55, but your budget probably won't go that far.

I am unsure about finishing the existing walls and joists here for a couple of reasons.

Before you think about finishing those walls, you should first think about beefing up the mass on the outside surface: as I outlined above, you need to add some more mass in between the studs, and improve the seal.

First, due to existing construction & space usage in my garage/ground floor, I am only able to finish the walls and joists that are highlighted above in blue, continuing to the back corner (just in the area of my intended build - shown in yellow). The rest of the walls and joists in the 33' x 28' garage/ground floor would remain untreated.

ALL of it should remain untreated! Sounds stupid, I know, but it's right. the rest of the garage does not matter. What you need to concentrate on is getting good mass in the outer-leaf, and completing that outer leaf, then creating your inner-leaf inside it. More on that below.

Second, since noise coming from outside the house is not my primary concern, I would only consider insulating/sheet rocking plywood walls and joists if it cut down the overall noise traveling down from the upstairs.

It's all part and parcel of the same thing. Sound going out through the house walls will came back in through the garage walls, if you don't do something about it. You need to create a consistent shell all around you, with roughly the same surface density on all sides. Isolation is only ever as good as the weakest link, so if you isolate three walls really well but did nothing to the fourth one, then you wasted your money on those three! sound will simply take the easy path through the fourth wall, bypassing the money you spent on the other three. Isolation is "all or nothing".

Want to prove it to yourself? Go sit inside your car in a noisy place with the doors and windows close. Now open one window... Even though the rest of the car is still doing the exact same job of isolating as before, all of that is bypassed because you created a "weak spot": the open window.

Also, If the room I build has it's own ceiling, separated from the above joists, Is there any reason for me to consider insulating/sheet rocking the existing walls and/or joists shown above in blue?

See above...

This is the exterior of the room I intend to build.

Your plan is flawed! It shows a 3-leaf system, when all that you need is a 2-leaf system. A 3-leaf system will ALWAYS have WORSE isolation in low frequencies when compared to the equivalent 2-leaf system, all other factors being equal. You are also wasting a lot of space with that design...

What you actually need to do, is to build only two walls initially... the two that you need to enclose the space completely. You already have two perfectly good walls there: the two existing exterior walls. Use them! They are two sides of your outer leaf. You need to built the other two sides. You already have the floor, and you already have the ceiling (floor above you). Those six sides create your outer-leaf. So frame up those two walls at the very limit of the area you can spare, and put two layers of 5/8" drywall on only ONE side of that frame: leave the other side unfinished. take that all the way form the floor to the ceiling. The concept is to build a shell that completely encloses your space,and is co,completely sealed, air tight, and has good mass on it, but only ONE leaf of mass, not two. The leaf might be made up of several layers, but they will be stacked on top of each other, on the same side of the studs: the other face of the studs has nothing on it.

To create the inner-leaf, you build something similar to what you show (wood frame with drywall), but you put drywall on only ONE side of that framing. So frame up the walls and ceiling, much like you show in your diagram, leaving a small gap between the existing outer-leaf wall and the new inner leaf wall. Fill the gap with insulation.

But the concrete is not level. There are not major holes, but surface varies up to 1 ¼".

That's a lot! Too much for rubber, too much for caulk, and you cannot afford to lose any headroom by pouring anything additional on top of that, such as another concrete pad... You really don't have many options here! you might just have to bite the bullet, and level it with hammer and chisel enough to get the sole plates to sit flat enough to be sealed with caulk.

I plan on laying sheets of ¾" plywood on the concrete for the interior floor.

... which would waste 3/4 inches of headroom, plus the 1.25" unevenness in the floor. That's 2 inches, wasted! You don't have that much to throw away. What I would do is to is this: after you have built the inner-leaf framing, pour self-leveling cement within the boundary created by the sole plates, so that it is just deep enough to cover the highest "bump" in the floor, plus 1/8". Then after that has cured, you are done! That can be your final floor surface. Use the type of self-leveler that is designed to be used like that, normally referred to as "topping", and use the type that allows for a minimum thickness of 1/8" (some cannot be thinner than 1/4").

I just read that using Plywood as the first layer of the interior leaf turns the entire wall into a screwing surface. I like that idea! So plywood on first layer, ⅝" sheetrock on top of that for the interior walls.

This would be 2 leaf system correct?

With your plan, it would be a 3-leaf system on the two sides facing the existing garage walls, as well as the ceiling. With my plan, it would be 2-leaf all around, it would save you space... and money!

On another note, based on the reading I have done, I can't determine if products like Green Glue and Quiet Rock will help my situation. If they will help, I would use them.

Green Glue would help, yes. Especially if you use it when you "beef up" the floor above you. Put it between the layers that you use up there. However, I doubt that your budget will allow you to use Green Glue: it is expensive, and you do need a lot of it.

I'll get back to you on the speaker/mix geometry later, but I'm out of time right now.

Hopefully the above is enough to get you on the right track.

- Stuart -

For now, I just want to thank you for replying Stuart. In scouring this forum for the last few months or so, it is crystal clear that you are putting in shit ton of energy into answering our posts. Absolutely no apologies needed. Actually, with your level of expertise, it's incredible to me that you can still find the time for folks like me. Yer likely not sleeping as much as you should -- No rest for the wicked! So, big props to you, and to all the folks that have invested their time to help build this forum.

I'm going take a couple days to wrap my head around your reply, by looking into existing information on the forum -- rather than posting a hasty response.

Thanks Again -cp

First, thanks for explaining why the noises seem louder in the garage -- makes a lot of sense.

Next, I can now see how my design is using both 2 & 3 leaf wall sections -- I'm less confused on leafs now. So thanks . However, just for the sake of learning, is there a ballpark distance where one could "factor out" an existing wall (leaf)? Maybe too complex to answer without specific details, and given your time, but I'm just curious.

A few quick points:
• I can place an area rug in the kids play area, and a long rug in the hallway. But that's about it. Wife likes the hardwood floor, so carpeting every where upstairs is not an option. Unless there are other ways to lessen impact noises, I suppose I will have to live with the isolation that the new room provides to battle these types of noises.

• Once I lock down the design details below, I will be able to calculate a more accurate construction material cost. Once I do this, I'll see if I can add Green Glue in the budget. Good news, is that I didn't anticipate the planning phase (learning process, really) to take as long as it has, and I've been able to stack some more bread ! So, I can up my budget to $7500 if it's neccessary.

• My plan was to use staggered stud walls -- 2x4 studs w/ 2x6 top and sole plates. Your approach didn't specify the style of framing, but it seems to me that you are suggesting I use standard 2x4 walls on 2x4 sole and base plates. (I didn't think I had enough room for a double walled approach, but it seems that I'm still climbing that learning curve. Thanks for schooling me). If standard 2x4 framing is in fact what you are suggesting, I'm fairly certain that I understand your approach, and it seems to make a whole lot of sense . I've started to revise my sketchup file, but before I do too much work on it, I am going briefly summarize my understanding of your approach to make sure I am not missing anything, and to ask a few additional questions.

• If you don't see responses to certain points you made in your last post, assume I am going to take your advice!

Step 1: To level floor, chisel concrete only where sole plates will be. I actually get a lot of satisfaction using the hammer and chisel. Yeah, a lot of work, but thanks for the suggestion.

Step 2: Remove plywood from existing walls. Insert carefully cut ⅝" drywall (sealed at the edges) into the frame bays of walls and ceiling (Joists). Two Layers? Should I use battens to hold these in place? Is that what you mean by cleats?

Step 3: Fill wall and ceiling frame bays with insulation. Should I use insulation clips to hold insulation in place? Or will it simply rest in place once the insulation from the opposing inner leaf and insulation in the air gap is in place?

Does the image below show the correct method to beef up the joists? Graphic is from John Sayers construction technique page - with some label changes for my situation. Step 4: Frame inner-leaf walls and ceiling using 2x4 studs on 2x4 sole and base plates. Anchor wall frames to concrete. Pour self-leveling concrete as you described. Fill gap between inner and existing outer leaf frames with insulation. Fill wall and ceiling frame bays with insulation. Connect one layer ¾" Plywood, followed by one layer of ⅝" drywall on the interior of the inner leaf walls and ceiling.

Step 5: Frame the 2 remaining outer-leaf walls from floor to ceiling. Anchor frames to concrete. Fill gap between inner and new outer leaf frames with insulation. Fill wall frame bays with insulation. Connect two layers of ⅝" drywall on the exterior of the outer leaf walls.
I realize you said -- "What you actually need to do, is to build only two walls initially... the two that you need to enclose the space completely," -- but I don't see how I would be able to build the inner shell if I built these two walls first. Perhaps I misunderstood.

Here's a floor plan showing the existing walls with plywood removed, and where the sole plates of the new inner and outer leaf walls would lay on the floor. In addition to the space your design saves me - I was actually able to add a couple more inches of width to the overall build space. Unfortunately, I lost a few inches in room length because of the spot that I need to tie the outer leaf into the existing walls -- I believe I would have to remove and frame up existing window to make the room longer. Dimensions shown are for the interior studio with a 2 layer (¾" plywood/⅝" drywall) leaf. The air gap between new inner and outer leaf walls is 1". There is also a 1" space between the base of the inner leaf walls and the brick footer. Moving upward, the air gap between the two inner leaf walls and the studs of the existing walls would increase to 9". That's a lot bigger than many of the examples I've seen, and significantly bigger than 1" air gap between the opposing wall frames. Will this be a problem?

Below is a detail of the base of the existing walls. You can see this in the sketchup file as well. I'm wondering if I can frame the 2 inner leaf walls that are closest to the existing walls on top of (and anchored to) the existing brick footer rather than on the concrete? Would this be considered "connected" to the outside leaf? If this is a sound approach, the air gap between these two inner leaf walls and the existing walls would be 4 ½" instead of 9". And I would gain the difference inside the studio. Keeping my fingers crossed on this one! Is the brick part of the outer leaf, or does it have properties similar to the concrete floor? Last questions: Is there a proper way to frame the new outer leaf walls to "step up" over the existing brick and wood footers so I can tie it into the existing walls? Also, the plan here assumes that the new outer leaf wall frames should be aligned in such a way, that the drywall on the exterior of these frames extend on to the bare stud face on the outside of the last beefed up existing wall bay. I'm also thinking that the same approach should be used where the top plate of the new outer leaf wall meets the existing parallel joist. I can place blocking between the joists so the outer leaf wall frame that runs perpendicular to the joists lines up. Is this all accurate?

I've read enough of your replies to other posts to know you like to remind us that sealing is wicked important -- Noted!
Also I know I have to squeeze in a step for HVAC. That will be the next hill to climb.

-Thanks for getting me on track Stuart!
Cliff