Trouble getting started and understanding...new construction

Hello all! I sure am hoping that some of you wonderful people can help me jump start my project studio. My goal is to mainly record my solo stuff and my band’s stuff and also have a few local bands in to do demo’s and small album projects. My location is over to the left in my profile badge. This is a new construction, so I don’t have dimensions per se. My wife and I are selling our current house and are planning to build a house once it is sold. We’re bouncing between two builders right now that both seem like good choices and are willing to build a studio to my spec and let me inspect the progress daily. The development will be on approximately a 1 acre lot in a housing subdivision. The main house will be approximately 2600 to 3000 sq ft, but most likely on the low end of that. I want a fairly decent size back yard and then the studio will be a separate building from the main house. It will be constructed on the outside to look like a three car garage with three bay doors. However, they will not be actual doors…just look like doors. I just want it to blend with the neighborhood and look as inconspicuous as possible. I spoke with the builders just the other day and gave them an approximate size of 30’ x 27’. I figured that’s roughly the size of a three car garage. This would be constructed on a concrete slab over compacted earth and the ceilings would be about 12’ (is that okay?). I told him that I wanted to kind of do rooms within rooms and told him I wanted double walls. Both builders seemed to understand this because both had experience building theatre rooms in the area. Both were intrigued by the recording studio idea so they could boost their resumes with that. Let me now say that I have read “Build It Like The Pro’s” by Rod Gervais. So, I do have that as reference. However, I understand very little in the book and even though I read stuff over and over, I can’t seem to grasp it. I’m not much in the way of “construction inclined” so to speak. I just know I want a two leaf system with two layers of drywall with Green Glue between the layers. I also want an HVAC system with plenty large ducts so the air moves nice and slow but in good volume. Additionally, I’m THINKING of going with a splayed laminate glazing to view the live room from the control room and of course, solid core doors of some sort. Now…I know I want a live room, a control room, an ISO booth, a rest room, and maybe a storage closet if I can get it in there. I’ll settle for some storage in the air lock, though, I suppose. Where I’m TOTALLY flabbergasted is on the actual floor plan of the studio. Do I want to go with all the angled walls? I mean, I plan to live in this house for a very long time, but wouldn’t I have better resale value if I constructed square rooms and just treated them with bass trapping and such? I know that non-parallel walls are the best and I’ll do them if I have to. The floor plan is a big one for me…I’m just lost. There’s so much information out there that I don’t know where to start, where to end, or anything, for that matter. Also, ceiling construction in Rod’s book was pretty confusing to me. I’m not sure I really understood it at all. I don’t necessarily want the decisions made for me...but I do need some help. I just want to make music…that sounds good and translates well. As for sound isolation, I’m not really all that loud. I don’t track a ton and I’m currently in an extra bedroom in my current house. I get some pretty decent results but I know they could be better. Where budget is concerned, I was told by the builder that they could stay in my budget. I hate telling what that budget is because housing markets vary so much. Let’s just say that the house I’m selling is almost 3000 sq ft…it’s a custom home that is less than 5 years old, granite, crown molding everywhere, 2 levels, 4 bedrooms, formal dining, study, all brick, privacy fence, professional landscaping, etc. It goes for about $300,000. The house I’m looking to build, I want to stay at or under $315,000…no exceptions. That’s WITH the studio. I hope I was detailed enough. I tried as best I could to follow the “Before You Post” rules. EDIT: Posted below is a picture I found on what I would likely do if I had non-angled walls. "WC" is where the restroom would be. By my dimensions, I'd have a little room left over from the overall length on this that I could use for storage, I suppose. Thoughts?

Hey Myriad! Welcome! Sounds like an interesting project! Starting from scratch, no existing walls, floor or ceilings to tie you down: You can do it pretty much any way you want! Cool! With your layout as it is now, I see a couple of issues that can probably be done more efficiently, and I've got some comments that might help you re-arrange things. Comments in no particular order of importance: Just the order I happened to think of them! Right now, you have no sight lines at all from your mix position into your live room and vocal booth. You usually want to be able to see in there, but your mix position is facing the wrong way for that. You might want to think about playing around with rooms, positions, angles and things. You might already know these, but there are a couple of rules of thumb to help you get your CR in shape (it looks like you already used some of them!): Your mix position should be roughly 38% of the distance from the front wall to the back wall. It's just a starting point, and not written in stone, but 38% is a good location regarding room modes. 50% is the worst possible location. With your head at the 38% position, the imaginary lines that are the acoustic axes of your speakers should intersect about 20 cm behind your head, at an angle of 60 degrees. Your speakers should be about 1.2 m above the floor, which is roughly your ear height when seated, and should be about 1 to 2 m apart, more or less. If you figure this out geometrically, then it will place your head and the speakers at the corners of an equilateral triangle. (you seem to have that already). Once again, those numbers and angles aren't carved in stone: They are just rough guide lines to get you positioned more or less correctly. Your control room (CR) should be perfectly symmetrical (left-right): Your LR can be built any shape you want (within reason!), and can be designed to "color" the sound a bit to your taste, if you prefer, or it can be designed to be neutral acoustically, but not dead sounding. The CR should be as neutral sounding as possible. It will need lots of bass trapping. Large bass traps. They work best in the corners of the room. Don't forget that a rectangular room has 12 corners! You might want to re-think your booth and WC: As it is, everyone has to go through the LR to get to the WC! Not only that, but you only have a single door from the WC into the live room, implying that the isolation won't be very good, so noises from the WC could potentially get into the LR... How about if you make some kind of access airlock (kind of like a miniature lobby) that has access into all three rooms, and put the WC on the OTHER side of that, well away from the rooms? You will need two back-to-back doors between the rooms, for good isolation, or one of Rod's massive "Superdoors" will also do the trick. Your CR dimensions should be calculated to match one of the "good" room ratios. If you want, you can splay the side walls and ceiling of your CR, to help create a good Reflection Free Zone (RFZ) around the mix position. If so, walls should be splayed about 6 degrees or more, and the ceiling should be splayed 10 to 15 degrees, with 12 being optimal. So you would be creating a kind of "funnel", with the speakers at the small end, widening out towards the rear wall. You don't have to splay the walls if you don't want: Many people do, for better acoustics, but many don't. You can still build a good room without splayed walls, and of course it makes the construction a bit harder. Pros and cons. Personal choice. Etc. Finally, you might want to consider flush mounting your speakers ("soffit mounting") to give you tighter bass and better imaging. Those pointers should maybe give you some ideas to get your design going! Also, I suggest that you download SketchUp and spend some time learning to use it. It's a 3D modeling package from Google, and it's FREE! It's probably the only free thing you'll get in your entire studio build, so make the most of it! It takes a while to learn, since it isn't very intuitive, but once you figure out the basics, its a very powerful tool. Most people here use it to design their studios, which makes it easy to exchange models with others, and for others to take a close look at your desigg from all angles, and suggest improvements. Anyway, once again: Welcome! - Stuart -

Stuart, thanks for the large reply and the welcomes! I appreciate your time. I have a couple of questions and such if that's cool with everyone. First off, like I said, I found that picture online somewhere and thought that it matched with what I wanted pretty well. However, since this is a new construction, I am flexible on what I will be doing, within reason. I think I may have fixed a few issues. I have given SketchUp a whirl and the attached image and skp file is as far as I have gotten...and trust me, this took me a while just go get this far! My questions/comments: I have drawn the SketchUp file to scale, but have altered the dimensions a bit. I'm going with a 36' by 25' building. Using the Sepmeyer Ratio from Rod's text, I calculated the CR dimensions based on a 12' ceiling height. That gives me a 12' x 13.68' x 16.68' CR. Going by the 38% rule, my head will be 6.34' into the room. Have I calculated all of this correctly? I want to incorporate a restroom into the design and I think I will do that in the far lower left corner of the drawing. Any problem with this? So are splayed walls generally a requirement? How much of a cost-advantage ratio am I looking at with splayed walls in the CR? Can I just adequately treat the room with bass traps, etc? Does the room need a QRD on the back wall? How does a rectangular room have 12 corners? I get 8. What does 'WC' mean? What kind of treatment would the ceiling require in the CR? I had figured on just suspeding some rigid fiberglass in wood frames. The reason I don't really want to soffit mount my speakers is because I want to have an upgrade path later. I don't want to have to reconstruct the soffits to match different speakers. I plan on using speaker stands. Would that be okay? General thoughts on my new design?

I have given SketchUp a whirl and the attached image and skp file is as far as I have gotten...and trust me, this took me a while just go get this far!

Tell me about it! Like you, I struggled for days trying to "get it". It takes a while to get the hang of how it works, and it sure ain't intuitive to start with. But once you get to know it, its pretty powerful. Try looking at some of the tutorials: I've heard they are pretty good.

... 12' x 13.68' x 16.68' CR.

Yup! That gives you a room ratio of 1 : 1.14 : 1.39. Sepmeyer #2.

Going by the 38% rule, my head will be 6.34' into the room.

Yup! But don't forget that 38% is not an absolute fixed "must be exactly here" position. It's just a starting point.

So are splayed walls generally a requirement? How much of a cost-advantage ratio am I looking at with splayed walls in the CR?

Not a requirement, no. Some people splay there walls, some don't. It helps with first reflection points and also with flutter echo. It looks cool, too! But it's harder to build.

Can I just adequately treat the room with bass traps, etc?

Yup. But you'll need lots of bass trapping either way. Splaying your walls won't reduce the need for treatment. The real advantages of splaying are helping you to get a better, cleaner image direct from the speakers, without reflections off the walls getting in the way, and without flutter echo messing things up.

Does the room need a QRD on the back wall?

Probably not. The room isn't big enough for a diffusor to be of much help. According to one school of thought, you need about six meters or so between the back of your head and the diffusor in order for it to be effective. Others say that even in a small room they can help. Personally, I don't see the need in a small room. You'll probably need to use most of the rear wall for absorption in any case, so a QRD would just take up some of that space. But that's my opinion. Others may disagree!

How does a rectangular room have 12 corners? I get 8.

:) count 'em! Four around the ceiling (wall-ceiling corners), four around the floor (wall-floor corners), and four around the room perimeter (wall-wall corners). Total 12.

What does 'WC' mean?

It's right there, on your original plan! I'm just using hte terminology that you used! As far as I know "WC" means "Water Closet", but most people call it a "toilet". :)

What kind of treatment would the ceiling require in the CR? I had figured on just suspeding some rigid fiberglass in wood frames.

Yup, that would work. That's a "cloud". You could also build your inner ceiling "inside out", meaning that hte drywall goes on top of the joists instead of underneath it. That gains you some extra height, if you want it, and leaves the stud space open to the room, so you can fill the entire ceiling with rockwool or fiberglass insulation.

I plan on using speaker stands. Would that be okay?

Yup. Stands will work too. Make them massive and decouple the speakers well.

General thoughts on my new design?

It's improving! So far, so good. I'd say your first priority is to bang your head against SketchUp some more, and get all those points into a real 3D model of your room. - Stuart -

Soundman2020 wrote:

Tell me about it! Like you, I struggled for days trying to "get it". It takes a while to get the hang of how it works, and it sure ain't intuitive to start with. But once you get to know it, its pretty powerful. Try looking at some of the tutorials: I've heard they are pretty good.

I'll do just that, thanks! I have a long way to go on it, that's for sure. Is the resulting SketchUp file something I can print out for a builder? I'm actually meeting a builder next week and he does 3D modeling. I might have him work something up using my specs and crude drawings. But I still need to work on my SketchUp skills.

Yup! That gives you a room ratio of 1 : 1.14 : 1.39. Sepmeyer #2.

I thought it was #1? Bah, no matter.

Not a requirement, no. Some people splay there walls, some don't. It helps with first reflection points and also with flutter echo. It looks cool, too! But it's harder to build.

Yeah, I'm afraid that splayed walls will really eat into my build budget from a labor perspective. As if a 2 leaf system isn't going to already. Speaking of, this space is roughly 900 sq ft. Would two 5 gallon buckets of Green Glue work? I think those cover a bit over 400 sq ft per bucket.

Yup. But you'll need lots of bass trapping either way. Splaying your walls won't reduce the need for treatment. The real advantages of splaying are helping you to get a better, cleaner image direct from the speakers, without reflections off the walls getting in the way, and without flutter echo messing things up.

I was planning on building superchunks in the corners out of rockwool using 2x4's for framing. Then covering with burlap and putting some nice trim on the edges. For the superchunks, I was going to cut the rockwool into triangles. I THINK I should get three triangles out of each sheet of rockwool. What about treatment for where the ceiling meets the wall? Should I straddle those corners with rigid fiberglass across the length of the room?

Four around the ceiling (wall-ceiling corners), four around the floor (wall-floor corners), and four around the room perimeter (wall-wall corners). Total 12.

I didn't think of the ones around the perimeter.

It's right there, on your original plan! I'm just using hte terminology that you used! As far as I know "WC" means "Water Closet", but most people call it a "toilet". :)

Yeah, I found those plans somewhere. Don't recall where. I didn't know what WC meant but thought it would be a good place for a restroom (toilet)...turns out that's what it was anyway.

You could also build your inner ceiling "inside out", meaning that hte drywall goes on top of the joists instead of underneath it. That gains you some extra height, if you want it, and leaves the stud space open to the room, so you can fill the entire ceiling with rockwool or fiberglass insulation.

Would I then cover the ceiling with drywall or cover the entire ceiling with burlap and some trim to clean it up?

Stands will work too. Make them massive and decouple the speakers well.

I'm currently using Auralex MoPads. That alright? Thanks again, Stuart. You've been most helpful in getting me off the ground with my design.

I thought it was #1? Bah, no matter.

You are absolutely right! It IS #1! Just my finger-trouble, typing too fast... Spelling checkers are great things, but they don't know much about how to correct wrong numbers! :)

I was planning on building superchunks in the corners out of rockwool using 2x4's for framing.

You could probably go lighter on the framing. 2x4 seems like a bit of overkill for just framing a stack of insulation.

For the superchunks, I was going to cut the rockwool into triangles. I THINK I should get three triangles out of each sheet of rockwool.

The front face of your triangle (the one that faces the room) should be 36" to get a really effective bass trap, according to something that I read somewhere but can't find again! 24" is also pretty good, but much less than that and it really isn't accomplishing too much. Now if I could just find that reference!

What about treatment for where the ceiling meets the wall? Should I straddle those corners with rigid fiberglass across the length of the room?

As Ethan would say: "You can't have too much bass rapping in a small room." His advice is always to go for as many corners as you can, comfortably.

Would I then cover the ceiling with drywall or cover the entire ceiling with burlap and some trim to clean it up?

Not drywall! that would make your ceiling into a third leaf. Burlap or acoustic cloth would be good. I do recall reading that some people are allergic to burlap fibers in the air, and some folks think that real acoustic cloth gives a more professional, neater appearance. Others like rustic. Personal preference, more than anything. Yo could just leave the bare insulation up there, or you could cover it with pretty much anything you like that is transparent to sound. - Stuart -

Thanks, Stuart. I THINK I have enough great info for now.

And fire retardant. Especially for over your head.

And fire retardant. Especially for over your head.

Good point!

Okay, I'm coming back with some questions that I have thought of. When building the main building, should I first do double walls (2 leaf) all the way around the perimeter of the inside of the building before I begin to construct the other walls that will create the CR, etc? How sturdy will the inside rooms be if they are decoupled from the main structure? The CR room, for example...will the integrity of the room be compromised by the fact that it is not directly connected to the main structure? Just curious. Would it be advantageous to put Green Glue on the concrete slab and then put a layer of 5/8" drywall on top of that before I begin construction of the rooms? Do I use 5/8" drywall on EVERYTHING that needs drywall? For the "inside-out" celing in the CR, would that extend into the live room, as well? Would all of the ceiling need to be "inside-out"? If I were to put rigid fiberglass up in the "inside-out" ceiling, how would I get it to stay so I can then trim and cover it? With what material? Obviously something that is fire-treated. On the top side of the "inside-out" ceiling, do I double up on the drywall with Green Glue in between? On the walls that connect the live room to the hall way and restroom, do I still need to decouple those walls as well?

When building the main building, should I first do double walls (2 leaf) all the way around the perimeter of the inside of the building before I begin to construct the other walls that will create the CR, etc?

No. Your outer wall is ONE leaf. Make it as massive as you can afford. Brick would be good. Concrete block would be good. Or stud frame with a couple of layers of OSB, plywood, etc. on the outside, followed by siding of some kind for your exterior surface. But it must be built as only one leaf. Each room is also built as only one leaf. That plus the outer core of the building gives you two leaves. You want ONLY two leaves, not three, not four. Just count the layers between you sitting at the mix position, and the outside world, or between you and any other room. If you get more or less than a total of two leaves, then something is wrong. Ditto for someone standing in the live room: two leaves to the outside world, or two leaves to any other room. Ditto for someone standing in the vocal booth: two leaves to outside, or to another room.

How sturdy will the inside rooms be if they are decoupled from the main structure?

You might need to brace them. There are several methods for doing that. Diagonal bracing is one. Sway braces is another. If you are going to use plywood or MDF as part of your leaf construction, then you don't need those. Even the drywall alone might be enough, although personally I'm not to keen on using drywall as a structural element!

Do I use 5/8" drywall on EVERYTHING that needs drywall?

Unless you can get something even thicker, then yes! :) Seriously, the more mass you can put in, the better your isolation will be. Thicker drywall should have a lower resonant frequency than thin.

For the "inside-out" celing in the CR, would that extend into the live room, as well?

Well. you wouldn't "extend" the same physical ceiling to the live room! But you could "extend" the same principle. Each room has it's own separate ceiling. Either or both could be built inside-out. Your choice!

If I were to put rigid fiberglass up in the "inside-out" ceiling, how would I get it to stay so I can then trim and cover it? With what material?

Package strapping, wire mesh, twine, etc. stapled across the joists.

On the top side of the "inside-out" ceiling, do I double up on the drywall with Green Glue in between?

If you have the budget, and want maximum isolation, then yes! But at the least, go with two layers of drywall.

On the walls that connect the live room to the hall way and restroom, do I still need to decouple those walls as well?

Decouple in what sense? As in build a two-leaf wall? If that's what you mean, then yes: Any wall that has the LR, CR or booth on the other side needs to be part of a two-leaf system. But walls between, for example, your kitchen and bathroom, or hall and bathroom, can just be normal stud walls, if you want. - Stuart -

Soundman2020 wrote:

No. Your outer wall is ONE leaf. Make it as massive as you can afford. Brick would be good. Concrete block would be good. Or stud frame with a couple of layers of OSB, plywood, etc. on the outside, followed by siding of some kind for your exterior surface. But it must be built as only one leaf. Each room is also built as only one leaf. That plus the outer core of the building gives you two leaves. You want ONLY two leaves, not three, not four. Just count the layers between you sitting at the mix position, and the outside world, or between you and any other room. If you get more or less than a total of two leaves, then something is wrong. Ditto for someone standing in the live room: two leaves to the outside world, or two leaves to any other room. Ditto for someone standing in the vocal booth: two leaves to outside, or to another room.

Okay, I think I understand. See my attached picture. The red lines are the second leaf.

You might need to brace them. There are several methods for doing that. Diagonal bracing is one. Sway braces is another. If you are going to use plywood or MDF as part of your leaf construction, then you don't need those. Even the drywall alone might be enough, although personally I'm not to keen on using drywall as a structural element!

Brace them to what? Wouldn't that then transfer sound to the other room via the bracing? I don't plan on using plywood or MDF as part of the leaf construction. Should I? What is the recommended way?

Well. you wouldn't "extend" the same physical ceiling to the live room! But you could "extend" the same principle. Each room has it's own separate ceiling. Either or both could be built inside-out. Your choice!

Yeah, I meant extending the same principle into that room. Not extending the actual ceiling. :cop:

If you have the budget, and want maximum isolation, then yes! But at the least, go with two layers of drywall.

I may have it in the budget. Green Glue isn't all that much, I suppose. I would, essentially, be doubling the amount of Green Glue, right? And really, I'm not all that sure how to figure how much of it I truly need. The space is approximately 900 sq ft. I think I need about 4 or 5 cases for the walls (minus the outside walls since the other side has brick). Then, I'll need to do the entire ceiling with Green Glue so I should probably get another 4 cases, right? Oh, and what about the concrete slab? Should I put two layers of drywall directly on the slab with Green Glue between them? Is that necessary or will the slab and the earth under it work just fine?

The red lines are the second leaf.

Yep, it looks like you got it!

Brace them to what?

Brace them to each other, using acoustic isolation sway braces, or brace them internally with triangular cross bracing or diagonals inside the wall. This is one kind of sway brace: There are other types too.

Wouldn't that then transfer sound to the other room via the bracing?

Not if it is a decoupled brace, designed for isolating vibration.

Green Glue isn't all that much, I suppose.

:!: It ain't cheap either! You need three tubes of GG per sheet of drywall for 100% coverage. That's nearly US$ 50 of GG per sheet. So treating 20 sheets of drywall will eat up around US$ 1000 from your budget...

Oh, and what about the concrete slab? Should I put two layers of drywall directly on the slab with Green Glue between them? Is that necessary or will the slab and the earth under it work just fine?

Concrete slab on grade is about the best you can get in terms of a good floor! The concrete is mass, the earth underneath is damping (not to mention also being a little more mass :) ). Use the bare concrete directly as your floor if it iis in good condition, or lay laminate flooring directly on top, or solid wood flooring, or something similar. Nothing with cavities in it, of course. No layers of air. - Stuart -

Brace them to each other, using acoustic isolation sway braces, or brace them internally with triangular cross bracing or diagonals inside the wall.

I'm assuming you connect the studs in the air space between the walls with these? I'll have to look into this a bit more. To me, triangular cross bracing or diagonals seems like they would transfer sound. If I were to use sway braces, at what intervals would I need to place them? I'd like to know more about the triangular cross bracing or diagonals inside the walls for bracing. Is there any documentation on this? In the mean time, I'll do a search here.

It ain't cheap either! You need three tubes of GG per sheet of drywall for 100% coverage. That's nearly US$ 50 of GG per sheet. So treating 20 sheets of drywall will eat up around US$ 1000 from your budget...

Hhhhmmm....I didn't think of it like that. I was figuring it on the square footage of the room and the estimates of how many a case covers. The website says a typical room takes 4 to 5 cases. I was going to go with 2 tubes per sheet. EDIT: I used a calculator on the Sound Isolation Store website. Looks like about 17 cases to do the CR, LR, and both ISO's with doing the ceiling too. Without doing the ceiling it's 13 cases.

Use the bare concrete directly as your floor if it iis in good condition, or lay laminate flooring directly on top, or solid wood flooring, or something similar. Nothing with cavities in it, of course. No layers of air.

Yeah, I was actually planning on using a nice looking (but fairly low cost, budget friendly) laminate flooring.

Myriad_Rocker wrote:

The red lines are the second leaf.

I don't think the double wall between the hallway and your Control Room/Live Room is needed. Also, if you were to build double walls, you would need double doors. That's 5 doors to go from the Control Room to the Live Room! I also doubt that dividing the hallway with that extra door will help isolation between the Control Room and the Live Room much. I would, however keep the double wall between the bathroom and the Live Room. Do you have some triple leaf action with your Iso Booths?

I don't think the double wall between the hallway and your Control Room/Live Room is needed.

Yes, I think you are right. Good point.

Also, if you were to build double walls, you would need double doors. That's 5 doors to go from the Control Room to the Live Room!

I was thinking of just using single solid core doors, actually. Would that be alright?

I also doubt that dividing the hallway with that extra door will help isolation between the Control Room and the Live Room much.

Yeah, I guess I could just have that hallway leading to the door of the live room with no additional door. I was just thinking in terms of an air lock of some sort. As far as doors go, I was really wanting to try and stay away from the inconvience of double doors. I know the alternative is a super door...but why not just solid core doors? I already have that hallway plus the 2 leaf system.

Do you have some triple leaf action with your Iso Booths?

Uh, what? What's a triple leaf and why would I need it in the iso booths?

You don't want three leafs in your iso booths, or anywhere else. It looks like your drawing shows triple leafs in a few spots. Working on a layout of decoupled rooms is counterintuitive because we are used to thinking of walls as simple partitions. Isolated rooms are independent freestanding structures that happen to be close to each other. Here's an overly simplistic exercise: Draw a rectangle as your outer leaf. Now draw two smaller rectangles inside that rectangle. Now you have a control room and live room. An iso booth can be it's own rectangle or a partitioned area of an existing rectangle depending on how much isolation you need. Arrange the rectangles so that the area left forms hallways, lounge, etc. Obviously rooms don't have to be rectangles, just an exercise.

stuntbutt wrote:

It looks like your drawing shows triple leafs in a few spots.

Ah, I see where you're talking about now. I'll fix it. That should get everything to a two leaf system that needs to be. EDIT: Attached is the updated floor plan. So...on the frames for the doors...will I end up connecting the two walls at this point so the door can be framed? Or is that the whole point of double doors? How do I get around having to have double doors but maybe eek my way around not having to have super doors? Or is that pointless?

I'm assuming you connect the studs in the air space between the walls with these? I'll have to look into this a bit more. To me, triangular cross bracing or diagonals seems like they would transfer sound.

Well yeah, but that doesn't matter, because you do them to the SAME wall! In other words, you run a diagonal piece of wood across the studs on your wall, inset into the studs if you want, or you do triangular bracing between the studs.... You don't connect one wall to another like that! I guess I didn't explain myself very well there! The sway braces connect frames to other frames, but the diagonal bracing or triangular bracing is internal to one specific wall.

I was thinking of just using single solid core doors, actually. Would that be alright?

If you build Rod's "superdoor", then sure, that would work. Lead sheeting, plywood, extra heavy duty hinges, triple seals....

So...on the frames for the doors...will I end up connecting the two walls at this point so the door can be framed? Or is that the whole point of double doors? How do I get around having to have double doors but maybe eek my way around not having to have super doors? Or is that pointless?

Do you have Rod's book? Look on pages 93-98 for info on how to build doors. Rod suggests that it is OK to join your inner and outer leaves at the door jamb, for sturdiness over time. He feels that the slight coupling there is outweighed by the benefits.

Soundman2020 wrote:

Do you have Rod's book? Look on pages 93-98 for info on how to build doors. Rod suggests that it is OK to join your inner and outer leaves at the door jamb, for sturdiness over time. He feels that the slight coupling there is outweighed by the benefits.

Yes, I do have his book. I didn't really understand the superdoor thing but I'm going to go back and review it. On another note, I met with a potential builder today. He asked if, instead of fiberglass insulation in the walls, could they blow in a cellulose insulation. He said that it would probably cover every nook and cranny of the wall so no air would escape, etc. As oppose to fiberglass, which would leave some gaps. Oh, and he also asked about blowing in a thin layer of foam inside the walls before the insulation goes in. Thoughts?

He asked if, instead of fiberglass insulation in the walls, could they blow in a cellulose insulation

Is that closed-cell or open-cell? If it is closed cell, then forget it. It has no acoustical benefits at all, and even worse, if it is rigid it will probably end up coupling your walls again! You can ONLY use open-cell insulation in your walls, NEVER closed cell. It needs to have the correct gas flow resistance properties, similar to that of mineral wool or fiberglass, and similar density (roughly 48 kg/m3). I would imagine that the stuff your builder is proposing is closed cell insulation. It sounds like he is looking for ways to cut corners. If he tells you it is open-cell, then ask for the manufacturer's spec sheet on the stuff.

As oppose to fiberglass, which would leave some gaps.

You WANT those gaps! The myriad of tiny air spaces between the fibers of rock wool or fiberglass insulation is exactly what you need! Those air-gaps-and-fibers create the exact acoustic properties that you WANT in your wall! That is how it damps your wall: sound waves penetrate through those air gaps, cause the fibers to vibrate minutely, and they in turn absorb the vibration by turning it into low-grade heat. That's how damping works. Yes, you do want an airtight seal on the SURFACES of your inner and outer leaf, but the cavity in between must be filled with OPEN CELL insulation, full of millions of tiny fibers and tiny air gaps. That is why closed-cell foam is useless. It sounds like your builder does not understand acoustics at all.

he also asked about blowing in a thin layer of foam inside the walls before the insulation goes in.

Why? What does he want to accomplish with that? Is that intended to seal the cavity air-tight? That is not a substitute for carefully sealing and caulking each layer of drywall as it goes up. Once again, it sounds like he is looking for shortcuts. Once again, I'd be concerned about that stuff maybe being too rigid, and possibly forming bridges between your leaves way inside the wall, where you can't see it, or creating flanking paths in other ways. - Stuart -

Soundman2020 wrote:

Once again, it sounds like he is looking for shortcuts.

He's not looking for shortcuts. He just doesn't understand. He said he would do whatever I wanted to do but he was just making suggestions. I told him I would check on it and he was perfectly fine with that. So, what kind of insulation should be in the walls? Would the fluffy pink stuff in rolls work? Just trying to understand what I really need to do. He's also checking on some industrial doors/sliding glass doors for me. Would these function as "super doors"? He was also worried that the live room wouldn't pass inspection. He said he would check with the city but he's fairly certain that the live room would need an exit point. He also said that he had some soundboard but I told him I was pretty firm in my decision to use Green Glue and drywall. He said that was fine with him. He was just asking. One final question...for now. :shock: :D Do the ceilings have to be 12 feet? We talked about how much more a 12 ft ceiling would be vs a 9 ft one. He just asked me to check on that so he could give a proper estimate for the entire project.

So, what kind of insulation should be in the walls? Would the fluffy pink stuff in rolls work?

Yup! That will work fine. It's a pain to work with, but he's the one who will be installing it, not you! :) Batts would be easier, but probably more expensive. Semi-rigid would also be easy. And also probably more expensive. Mineral wool is also good.

He's also checking on some industrial doors/sliding glass doors for me. Would these function as "super doors"?

They might work if they are massive, and seal very well. But they wouldn't really be superdoors. It's only a superdoor if you build it like Rod says! And that means layers of lead sheeting and plywood bonded to the solid-core door itself, plus three separate seals on three separate jambs, and oversize hinges, screws and jambs... It just ain't a Superdoor otherwise! But if you can get a good thick massive solid-core door with good seals, that would work. Sliding glass doors will work too, if you do them like John does.

He said he would check with the city but he's fairly certain that the live room would need an exit point.

Bummer! That means you have to put another pair of doors in there somewhere? Ouch.

Do the ceilings have to be 12 feet? We talked about how much more a 12 ft ceiling would be vs a 9 ft one.

Well, they don't HAVE to be 12 feet, as in "life or death", but if you have the space and can afford it, then I'd go for it, if it were my room. Extra volume is always good, acoustically. Going from 12' to 9' decreases your room volume by 25%. On the other hand, if that would put the entire build out of your budget, well, then you just have to live with what you have! Maybe you could go somewhere in between? Maybe 11', or 10'6, or 10' might be more doable? But once again, if it would break the bank or prevent you from building, then sure, go down to whatever size you need. But don't forget to re-calculate your room ratio: it will change drastically if you drop your ceiling by 25%. You might need to re-design walls, door positions, window positions, etc. What ratio are you using right now? - Stuart -

They might work if they are massive, and seal very well. But they wouldn't really be superdoors. It's only a superdoor if you build it like Rod says! And that means layers of lead sheeting and plywood bonded to the solid-core door itself, plus three separate seals on three separate jambs, and oversize hinges, screws and jambs... It just ain't a Superdoor otherwise! But if you can get a good thick massive solid-core door with good seals, that would work. Sliding glass doors will work too, if you do them like John does.

I'll have to set aside some time tonight to really examine that superdoor section of Rod's book.

Bummer! That means you have to put another pair of doors in there somewhere? Ouch.

Yeah...but I think he said that's only if we plan on using it as a living space later on. I'll have to clarify with him and he was going to check with the city to make sure. They might say that I have to have one there, anyway. Which sucks...

Well, they don't HAVE to be 12 feet, as in "life or death", but if you have the space and can afford it, then I'd go for it, if it were my room. Extra volume is always good, acoustically. Going from 12' to 9' decreases your room volume by 25%. On the other hand, if that would put the entire build out of your budget, well, then you just have to live with what you have! Maybe you could go somewhere in between? Maybe 11', or 10'6, or 10' might be more doable?

We discussed it and his thing was the labor and material waste of cutting the sheets, actually. So, I think it's probably 9' or 12'. Anything more than 9' would require cuts so might as well do 12' if I'm going above 9'. But I'll have to see how the estimate comes out. :?

What ratio are you using right now?

I'm using Sepmeyer #1. 1: 1.14: 1.39