Recording Studio project with no available resources - Pt. 1

[memocn59]

Hi! I have been in this forum for a few days and have to say Gregwor has been really helpful. Following his advice, I will try to make this post the most information dense about my project so I hope this can help others. I will attach some pictures and drawings to help you guys see what I see. Let´s start!

Background:
Space is no negotiable, the proyect should be done inside a two floor building that is in front of a heavy traffic avenue but this is the only space we have. The studio will be on the second floor (thank god) and we can use the space of two adyacent offices which will be the control and live room.

Drawing for the building:

af04c6ee-4186-4ddf-84b6-84805ff16dfe.jpg

Drawing for the two offices:

c56c596d-090c-4594-80dc-de3c7832ced9.jpg

From several videos on youtube I know that my rooms don´t have enough volume (planning to record drums and mixing), they are too small. But this is the only option, I should take it or leave it.

As you can see, room to the left is a little bigger than the other one. That´s what I decided to be the Live room (a little more space, less pressure at least in comparison with the other room). I decided to use the little room to be the control room since somehow one tends to get to know the room, you get used to hear your room. I mean, while it´s far from ideal dimmensions one can always compensate with proper experience and understanding of the room.

Previous Tests:

I didn´t really measure the noise from one room to another. I just ran my monitor speakers very loud (song playback to which level I could say a drummer could rehearse comfortably) and hear at the other side. Anyways I got some sound in the other room... It was like hearing music far away (mostly mid lows and lows). So I decided that maybe it was a good idea to reinforce that wall to be more soundproof. This is when I came across concepts like three leaf effect and decided to work with a two leaf design.

Later on, I decided I wanted an acoustic window of 1*1.5m . Why that big? well I wan´t to see the whole room and also it looks pretty cool. So I got someone to break the wall.

Acoustic window hole:

427fb77b-804e-4bfd-959f-2a81bb82aec1.jpg

Where to put the new wall (leaf)?

Well since I discovered in youtube that coincidental room sizes (those close to a square) are not desirable I decided to put the new wall on the Control Room since this would improve numbers a little bit by making them a little different and that way, avoiding hurting even more the live room. Basically I´m keeping the live room the same while making the control room more of a rectangle... although sacrificing the long distance =(

48db8ef8-9a33-49d3-8bab-2bce2b9e1235.jpg

So now I have to make a decision for the type of second leaf I will choose:

Option A:
15 cm Brickwall
11 cm air gap before reaching the stud
2x6 studs filled with insulation
3 layers of 5/8 drywall (10.74 kg/m2)

Drawing of the intended leaf:

a8709f12-e99d-450a-8edd-d45344c1dab6.jpg

Here you can see my results using Gregwor calculator:

tablaroa + ladrillo datos.jpg

tablaroa + ladrillo resultados.jpg

Option B:
15 cm Brickwall
15 cm airgap with 2" insulation
15 cm brickwall

e197ed72-c773-450d-9a92-f47af1a5d053.jpg

Again, my results:

ladrillo + ladrillo datos.jpg

ladrillo + ladrillo resultados.jpg

Considering two brickwall leafs... how would you add insulation to the interior between leafs?

Note: Both the old and the new walls are touching the lateral walls, ceiling and floor. But leaf A is not touching Leaf B.

Regarding the results: How do I know which is my resonant frequency, what does F1 means? and how is the use of insulation affects the graphic? is the graffic considering use or no use of it?


It´s worth noting that construction materials in mexico appear to be cheaper when using concrete... Option B and Option A would cost almost the same for me... about 400 USD. Option A appears to issolate less but option B has problems in the low end. Which option would you suggest is better in your experience?

What could you recommend that would improve the performance? I´m not using resilient channels, isolation clips or greenglue because it´s either too expensive here or difficult to get.

Window:

I have someone to build the acoustic window I can´t say too much right now about it. All I know by now is that will consist of two double layer glass with one of them laminated... One of the reasons I decided to add another wall is to give the window a chance to improve soundproof by having more aire space... I will suggest the builders to build the window in two frames so each frame could sit in each wall without touching each other.

Any suggestions of how thick or which kind of glass to use in order to mantain the sound transmission loss?

If my window is built in two separate frames so how do you keep the window from letting the interior of the wall to be seen?

[Gregwor]

Awesome that this is now officially your design/construction thread! Congrats!

The studio will be on the second floor (thank god)

The bad thing about second floor builds is that you need to make sure the floor can handle the crazy weight of the studio materials. What is your floor made out of exactly?

Drawing for the two offices:

What are your ceiling heights? What are they made out of?

Are you able to move the doors? They're both in HORRIBLE spots.

Do you have a separate air handler unit for your second floor spaces (separate from the downstairs)?

From several videos on youtube

Honestly, I'd stay off of YouTube. It is littered with horribly incorrect information.

I know that my rooms don´t have enough volume (planning to record drums and mixing), they are too small. But this is the only option, I should take it or leave it.

Having a recording space is better than not having one!

I know you like the idea of having two separate rooms and a glass window,etc. But have you considered having one large room with variable acoustic devices to change the acoustic response of the room for tracking or mixing sessions? This would allow you to have totally decent acoustics for both purposes rather than not ideal acoustics in both of your small rooms. The only challenge would be figuring out if that existing concrete wall is load bearing or not.

room to the left is a little bigger than the other one. That´s what I decided to be the Live room (a little more space,

I decided to use the little room to be the control room since somehow one tends to get to know the room, you get used to hear your room. I mean, while it´s far from ideal dimmensions one can always compensate with proper experience and understanding of the room.

There certainly may always be some weird responses in the room that you will have to suffer with, for sure. But, the idea is to treat the hell out of the room to try and fix as many problems as possible. Look at the corner control room studio that we are wrapping up right now -- it's basically square and it is turning out to be awesome!

This is when I came across concepts like three leaf effect and decided to work with a two leaf design.

So you're only going to have a decoupled inner leaf for your control room and you'll leave the live room as is (isolation-wise)?

Later on, I decided I wanted an acoustic window of 1*1.5m . Why that big? well I wan´t to see the whole room and also it looks pretty cool. So I got someone to break the wall.

Glass is great, but expensive.

Well since I discovered in youtube that coincidental room sizes (those close to a square) are not desirable I decided to put the new wall on the Control Room since this would improve numbers a little bit by making them a little different and that way, avoiding hurting even more the live room. Basically I´m keeping the live room the same while making the control room more of a rectangle... although sacrificing the long distance =(

First off, due to the small size of the room, I'd personally probably leave the dimensions as they are and try to maintain as much of that space as possible. I'd rather have more space than a better room ratio.

If you're set on improving your room ratio, I'd make the room skinnier and leave the length if possible. Length is very important to try to obtain the longest Initial Time Delay Gap as possible.

Considering two brickwall leafs... how would you add insulation to the interior between leafs?

Great question. I have no answer.

Note: Both the old and the new walls are touching the lateral walls, ceiling and floor. But leaf A is not touching Leaf B.

Correct, so due to structure borne vibration, you're going to trash your isolation. Therefore there is no point in adding this second wall.

How do I know which is my resonant frequency, what does F1 means?

F1 is the frequency at which from that frequency and up, you reach your maximum transmission loss value.

and how is the use of insulation affects the graphic?

Insulation GREATLY improves the amount of isolation.

is the graffic considering use or no use of it?

If you look at the top of the graph, it says "Transmission Loss in dB with insulation (isothermally)"

Option B and Option A would cost almost the same for me... about 400 USD.

Option A using the wood frame and 3 layers of drywall would include an ENTIRE new room built inside of the exiting room, right? That means 4 new walls, another acoustic door, and a new ceiling. None of it touching anywhere except the floor, right? $400 USD seems REALLY REALLY REALLY cheap to do that. I couldn't buy the wood to frame a new room let alone engineered ceiling joists or the required drywall for that amount of money. Unless you're not considering the other 3 walls and ceiling, Mexico sounds like the place to build a studio price-wise!

What could you recommend that would improve the performance?

Just make sure everything is sealed and there is no flanking anywhere. Make sure that your HVAC is designed properly to provide the appropriate insertion loss. Make sure your doors and windows maintain your surface density and have great seals on them. Build it with care.

I´m not using resilient channels, isolation clips or greenglue because it´s either too expensive here or difficult to get.

Green Glue Compound is awesome. The GG Sealant sucks. RC and isolation clips are the wrong thing to use in YOUR build. If you're looking to improve the existing isolation for your brick separated room, you need to build a fully decoupled MSM room.

All I know by now is that will consist of two double layer glass with one of them laminated.

Any suggestions of how thick or which kind of glass to use in order to mantain the sound transmission loss?

Both need to be laminated and if you want to maintain the isolation that you would have had without a window, then your glass MUST match the same surface density as the brick had. So:

15 cm of red brick = ~ 264.75 kg/m2
10 cm of laminated glass = ~ 250 kg/m2
Therefore, you should play it safe and use a bit thicker:
11 cm of laminated glass = ~ 275 kg/m2

The problem is, try and find glass that thick. You MIGHT be able to find some somewhere, but it'll cost about as much as a space shuttle. Oh, and remember, you need one in each wall, so two of them!

I will suggest the builders to build the window in two frames so each frame could sit in each wall without touching each other.

This can't be a suggestion. It needs to be an order. This is very important.

If my window is built in two separate frames so how do you keep the window from letting the interior of the wall to be seen?

There are several threads on the forum showing how people have built their windows. I'd suggest looking at some to get ideas. It's pretty hard for me to write out a detailed description. But in short, you can build your frames to only leave a small (like 1") gap between the two frames. Then, use some rigid insulation (like OC 703) sitting over top of that part of the frame to bridge the gap. In that insulation, you can cut out some insulation to place some desiccant. Then, wrap the insulation with a colored fabric. That's it!

I know some of what I wrote is bad news, but hopefully this gets your design on the right track!

Greg

[memocn59]

The bad thing about second floor builds is that you need to make sure the floor can handle the crazy weight of the studio materials. What is your floor made out of exactly?

It´s called bovedilla. It´s kind of a hollow block filled with masonry.

What are your ceiling heights? What are they made out of?

2.35 M

Are you able to move the doors? They're both in HORRIBLE spots.

No, I can´t because for the live room the next available space is an empty space for the stairs… No floor. And for the control room there is no space avaible to the sides because there is the Wall for other room.

Do you have a separate air handler unit for your second floor spaces (separate from the downstairs)?

I really don´t understand what you are talking about. Could you explain please?

Honestly, I'd stay off of YouTube. It is littered with horribly incorrect information.

Actually I saw a lot of acoustic fields videos, I think those are good but then I noticed how he almost always says the same. Room volumen, and usage, low frequency is hard to manage, and measurements haha. Further from that.. not much new knowledge

I know you like the idea of having two separate rooms and a glass window,etc. But have you considered having one large room with variable acoustic devices to change the acoustic response of the room for tracking or mixing sessions? This would allow you to have totally decent acoustics for both purposes rather than not ideal acoustics in both of your small rooms. The only challenge would be figuring out if that existing concrete wall is load bearing or not.

Didn´t consider that. Honestly I don´t know how that would be. Is there any search tearm I can use to learn more?

There certainly may always be some weird responses in the room that you will have to suffer with, for sure. But, the idea is to treat the hell out of the room to try and fix as many problems as possible. Look at the corner control room studio that we are wrapping up right now -- it's basically square and it is turning out to be awesome!

How can I look at the corner control room studio? I want to

So you're only going to have a decoupled inner leaf for your control room and you'll leave the live room as is (isolation-wise)?

Yes, that´s what I plan to do... Only difference being the addition of the acoustic window

First off, due to the small size of the room, I'd personally probably leave the dimensions as they are and try to maintain as much of that space as possible. I'd rather have more space than a better room ratio.

If you're set on improving your room ratio, I'd make the room skinnier and leave the length if possible. Length is very important to try to obtain the longest Initial Time Delay Gap as possible.

Well, the original plan was to put monitors to the right of the window. I mean, If I were sat in the mixing position I would have to turn my head to the left in order to see the window. This way, I would have the monitors facing the lenght of the room. However, furniture doesn´t fit very well this way. That´s the reason I changed my mind to put monitors infront of the acoustic window.

Correct, so due to structure borne vibration, you're going to trash your isolation. Therefore there is no point in adding this second wall.

I really have some trouble understanding this. I mean, two walls should be better than one right? I Will tell you a Little story. A year ago I built a super Little studio. Actually I built that studio in the room that now Will be the live room… I divided that room in two rectangles. Live room and control, both super reduced in space, heat was horrible. By that time I knew even less about acoustics so I got someone to install Steel studs (which now I know where hollow, surely creating resonances inside the stud tubes) we fill that stud with fiberglass (the pink one)… We put a layer of cardboard filled with sand (1 cm thick and we didn´t sealed between plates ) and a single layer of 1/2" gymsumboard each side. The Steel studs was like 2x2, they were kind of thin so the final thickness of the whole Wall was about 6cm. That same Wall had an acoustic window of 1.3*.80 m with two layers of glass (9mm laminated and a 6mm normal). Also there was a cheap door on that Wall. Another point to add. I never sealed the hole for the cables... This was a 2" hole near the floor.

The reason I built this Wall was because I was getting traffic noise from the building´s window. So the control room was the nearest room to the traffic and the live room was separated from the building´s Wall and that 6cm Wall I build. That Wall was in touch with ceiling and floor. Soundproofin wasn´t too good but sometimes was difiicult to hear someone talking from one room to another and also I could have my recording takes free traffic noise most of the time (low frequency noise was however imposible, these times I needed to repeat the take). When inside the live room you could hear noticeable more noise with the door open and much more silence when closing the door.
While not perfect I was way better with this thin Wall thank without it… Without it I would never be able to record takes without noise… Here you can see the old Little studio and hear one of the tracks I recorded and mixed in there… I´m the one with the guitar but no singing--> https://www.youtube.com/watch?v=MuUqZJ13giU

This leads me to… Should I expect gains in adding this new Wall in my new proyect? Could you please explain a Little further about structure borne vibration? Will this affect when playing instruments? this building is all made of brickwall and concrete. Pure solid construction. Or do you mean that I going to have some noises pass the barrier? I´m ok with some noises madking through the Wall once in a while as long as not instrument noises. I really care about isolating while tracking recordings.

If you look at the top of the graph, it says "Transmission Loss in dB with insulation (isothermally)"

haha that´s true , sorry

Option A using the wood frame and 3 layers of drywall would include an ENTIRE new room built inside of the exiting room, right? That means 4 new walls, another acoustic door, and a new ceiling. None of it touching anywhere except the floor, right? $400 USD seems REALLY REALLY REALLY cheap to do that. I couldn't buy the wood to frame a new room let alone engineered ceiling joists or the required drywall for that amount of money. Unless you're not considering the other 3 walls and ceiling, Mexico sounds like the place to build a studio price-wise!

haha, no. I´m only considering the one Wall to reinforce the existing one. Later I would like to do something alike one more Wall in order to soundproof from Street noise.

Green Glue Compound is awesome. The GG Sealant sucks. RC and isolation clips are the wrong thing to use in YOUR build. If you're looking to improve the existing isolation for your brick separated room, you need to build a fully decoupled MSM room.

I don´t think this Will be inside my financial reach =( but however, could you point to some resource in order to learn how to do this?

Both need to be laminated and if you want to maintain the isolation that you would have had without a window, then your glass MUST match the same surface density as the brick had. So:

15 cm of red brick = ~ 264.75 kg/m2
10 cm of laminated glass = ~ 250 kg/m2
Therefore, you should play it safe and use a bit thicker:
11 cm of laminated glass = ~ 275 kg/m2

The problem is, try and find glass that thick. You MIGHT be able to find some somewhere, but it'll cost about as much as a space shuttle. Oh, and remember, you need one in each wall, so two of them!

whoa those are carzy numbers and sound very very expensive… Is this the way pro´s make this? also, is there any formula to calculate the transfer los of the window considering air gap



Thank you for your kind help It has been truly useful.

[Soundman2020]

Actually I saw a lot of acoustic fields videos,

As Greg said: the Internet is littered with horribly incorrect information!

How can I look at the corner control room studio? I want to

Here you are: Link to the corner control room thread

That´s the reason I changed my mind to put monitors infront of the acoustic window.

But that means you can't get them in a good location, and you can't put the needed treatment in there, because of the door...

I really have some trouble understanding this. I mean, two walls should be better than one right?

If you build the isolation system correctly, yes. But if you don't build it correctly, then as Greg said, the isolation can be worse that it would be with just a single wall.

Soundproofin wasn´t too good but sometimes was difiicult to hear someone talking from one room to another

So sometimes you could hear conversations in the next room, and sometimes not? That's very poor isolation. Probably less than 30 dB.

low frequency noise was however imposible, these times I needed to repeat the take

Exactly: Due to the very poor isolation. The low frequency end of the spectrum is ALWAYS the worst part, in any isolation system. If you can get the low end isolated well, then automatically, the rest of the spectrum will be isolated even better.

This leads me to… Should I expect gains in adding this new Wall in my new proyect?

Absolutely, yes! The isolation will be MUCH better, if you build it right.

I´m only considering the one Wall to reinforce the existing one.

That's a common mistake: The additional wall does not actually "reinforce" the isolation of the other one. Rather, both walls act TOGETHER as a system. This is not so easy to understand, because it is not intuitive, but the situation is NOT that sound is partly blocked by one wall, then carries on and is blocked some more by the other wall. That's not how it works. Rather, the walls work together, as a tuned resonant system, and like that they block the sound. Together, not individually. It is the SYSTEM of two walls that isolates the room, not the two individual walls. So you have to "tune" the wall system to get the isolation that you want.

I don´t think this Will be inside my financial reach =( but however, could you point to some resource in order to learn how to do this?

Here: https://www.greengluecompany.com/produc ... g-compound .

whoa those are carzy numbers and sound very very expensive…

Then decide how much isolation you need, in decibels, and the lowest frequency you need it, and design the windows for that situation. You can probably get decent isolation with glass that is about 15mm to 25mm thick, if your air gap is large enough, and you seal the windows in properly, with good insulation around the perimeter.

also, is there any formula to calculate the transfer los of the window considering air gap

It's the same as for the walls: just use the density of glass, instead of the density of concrete or brick.

[memocn59]

Hey! I´m returning to my project post. First of all, thanks for all the great information provided... Frank´s studio is looking great and pretty ingenious!

I have now a different question... For what I ´ve understood... In a two leaf system, insulation is used to control the resonances created inside the wall. I have also undestood that one must avoid too rigid material since this could transfer enegy by coupling two walls if they make some contact.

So, which density would be the correct. In México roxul is a little bit complicated to get. I´m considring a mexican brand called rolan and the provider is offering me a density of 4lbs at 2". Will this work well?

Also, if considering a stud of 2x6... Is it woth it to use two layers of 2" mineral wool? I mean, is it better to fill with insulation every air cavity? or a single layer is enough?

[Soundman2020]

I have also undestood that one must avoid too rigid material since this could transfer enegy by coupling two walls if they make some contact.

There's no problem using semi-rigid insulation: what is important is to use the right density of insulation, and that is different for different TYPES of insulation. If your insulation is fiberglass, then the right density is around 30 kg/m3, or roughly 2 lbs/ft2 (pounds per cubic foot, or PCF). But if it is mineral wool, then it needs to be about 50 kg/m3, which is roughly 3 lbs/ft2 (PCF).

I´m considring a mexican brand called rolan and the provider is offering me a density of 4lbs at 2". Will this work well?

4 PCF is a little high, (it's about 65 kg/m3), so if you could find something a little lighter, that would be better. Is that mineral wool or fiberglass? Do you have a link to the product itself, on their website?

Also, if considering a stud of 2x6... Is it woth it to use two layers of 2" mineral wool? I mean, is it better to fill with insulation every air cavity? or a single layer is enough?

Always fill the entire cavity as much as you can, but without forcing the insulation in. So if the cavity is 6" deep, then use three layers of 2", and that will fill it fine.

The reason is simple: the insulation does several things, and one of them (as you mentioned) is to damp the various resonances going on inside the wall, all of which rob you of isolation. Another thing it does is to change the way air behaves with regard to heat, from adiabatic to isothermal. That's two different mechanisms for handling heat, and isothermal is better.... It also accomplishes something else, which is to reduce the speed of sound! Sound travels more slowly inside the insulation, and therefore the path across the cavity "seems" longer, from the point of view of the sound wave, and that is good! But if you only fill the cavity half way, then you only get half of the benefit! So fill it all the way.

You can mix different types of insulation if you have to. For example, you could have 4" of mineral wool between your studs, then another 2" of fiberglass on top of that, so it sticks out half an inch into the empty part of the cavity, (the studs are 2x6, so they are 5 1/2" deep), then if the inner leaf happens to be 2x4 (3 1/2" deep), you could put another 4" of either mineral wool or fiberglass in there, which would also stick out 1/2". That would mean that your two frames would need to be 1 inch apart.

Of course, it's a lot better if you just use the same type of insulation throughout the entire wall, but if you run out of one type, then you can use the other type to fill the remaining gap.


- Stuart -

[memocn59]

I have also undestood that one must avoid too rigid material since this could transfer enegy by coupling two walls if they make some contact.

There's no problem using semi-rigid insulation: what is important is to use the right density of insulation, and that is different for different TYPES of insulation. If your insulation is fiberglass, then the right density is around 30 kg/m3, or roughly 2 lbs/ft2 (pounds per cubic foot, or PCF). But if it is mineral wool, then it needs to be about 50 kg/m3, which is roughly 3 lbs/ft2 (PCF).

I´m considring a mexican brand called rolan and the provider is offering me a density of 4lbs at 2". Will this work well?

4 PCF is a little high, (it's about 65 kg/m3), so if you could find something a little lighter, that would be better. Is that mineral wool or fiberglass? Do you have a link to the product itself, on their website?

Also, if considering a stud of 2x6... Is it woth it to use two layers of 2" mineral wool? I mean, is it better to fill with insulation every air cavity? or a single layer is enough?

Always fill the entire cavity as much as you can, but without forcing the insulation in. So if the cavity is 6" deep, then use three layers of 2", and that will fill it fine.

The reason is simple: the insulation does several things, and one of them (as you mentioned) is to damp the various resonances going on inside the wall, all of which rob you of isolation. Another thing it does is to change the way air behaves with regard to heat, from adiabatic to isothermal. That's two different mechanisms for handling heat, and isothermal is better.... It also accomplishes something else, which is to reduce the speed of sound! Sound travels more slowly inside the insulation, and therefore the path across the cavity "seems" longer, from the point of view of the sound w

ave, and that is good! But if you only fill the cavity half way, then you only get half of the benefit! So fill it all the way.

You can mix different types of insulation if you have to. For example, you could have 4" of mineral wool between your studs, then another 2" of fiberglass on top of that, so it sticks out half an inch into the empty part of the cavity, (the studs are 2x6, so they are 5 1/2" deep), then if the inner leaf happens to be 2x4 (3 1/2" deep), you could put another 4" of either mineral wool or fiberglass in there, which would also stick out 1/2". That would mean that your two frames would need to be 1 inch apart.

Of course, it's a lot better if you just use the same type of insulation throughout the entire wall, but if you run out of one type, then you can use the other type to fill the remaining gap.


- Stuart -

Thanks I will use mineral wool 3lbs then.

Is this useful?

Sin título.jpg

Will try fo fill the whole cavity then

[memocn59]

A question I´ve never though about before

I´m using 2x6 wood studs and planning to put 3 layers of 5/8 gypsum board... Which is the correct way to attach them to the stud...

1. I´m planing to make sure that the endings of the each plate from the first layer don´t match other edges from another plate of the second or third layer... I´m having trouble explaining this in english haha... What I mean is, If I fix the plates in the same order I will end up with little air pasages where the boards touch with each other... I´m trying to stop and block this passages by installing the boards in different orders. Is this ok?

2. How to screw the boards? I´m not using green glue, just pure gympsum boards. Should I attach the 3 layers of gymsun directly through the studs by one single screw? I mean, all the boards attached directly to the studs, So the last board´s screw would pass through the other two directly to the stud. Or should I attach first board to the stud... second board to the first board, and third board to the second board?

[Soundman2020]

I´m using 2x6 wood studs and planning to put 3 layers of 5/8 gypsum board... Which is the correct way to attach them to the stud...

Usually nails. Proper drywall nails, of course. Or screws.

make sure that the endings of the each plate from the first layer don´t match other edges from another plate of the second or third layer... I´m having trouble explaining this in english

Right! That's called "staggering the joints", and it is in deed the correct way to do it... and is VERY important!

Some people also put the second layer on horizontally, instead of vertically, but then you need noggins across the framing at the correct locations, so you have something to nail the edges into.

I will end up with little air pasages where the boards touch with each other...

Fill those gaps with caulk. Seal EVERYTHING.

Should I attach the 3 layers of gymsun directly through the studs by one single screw? I

No. Each layer needs to be nailed in place individually. Your local building code should specify the "nailing schedule", which describes how far apart the nails have to be, maximum. Use half of that nailing schedule on the first layer, then the other half on the second layer, then do the third layer with the full nailing schedule, but "staggered" (offset" by an inch or two, to ensure that the final nails do not hit the nails that are already there on the other layers. And of course, for each successive layer, you need longer nails! The nails on the last layer MUST penetrate as deep into the studs as the nails on the first layer...

Or should I attach first board to the stud... second board to the first board, and third board to the second board?

All panels Must be nailed into the studs.


- Stuart -

[memocn59]

Hi I now have a question regarding acoustic window… I have read several times gregwor post but I still have some questions:

1. You have two window frames, each installed on each leaf right? So the fabric is the only thing that get them as one piece? I supose since fabric is so thin and flexible this can´t couple the window

2. I have read that the window cavitiess (the ones that we would see if no fabric was added) should be filled with insulation… This could end like a frame of insulation

3. Is this correct, how would you hold the mineral wool to the sides of the window, top and bottom?

4. How do you know how many material you need in order to avoid humidity? If I understand correctly, a single frame window will have to control humidity only in the window cavity... With decoupled window we must control humidity of the whole wall?

5. How do you place this material into the wall or window?

Thank you!! =)

[Soundman2020]

1. You have two window frames, each installed on each leaf right? So the fabric is the only thing that get them as one piece? I supose since fabric is so thin and flexible this can´t couple the window

Correct. Fabric is very flexible, very low mass, and will not couple the leaves.

2. I have read that the window cavitiess (the ones that we would see if no fabric was added) should be filled with insulation… This could end like a frame of insulation

Correct. You do want insulation exposed to the perimeter of the window cavity. It helps damp the resonances inside that cavity, to a certain extent.

3. Is this correct, how would you hold the mineral wool to the sides of the window, top and bottom?

There are several methods, but the easiest is to use sem-rigid insulation in that area, cut to the same size as the gap, and wrap it with the fabric. Then just press it into place, and perhaps put a dab of glue on just ONE edge, to make sure that it stays on place. Another option is to use strips of packaging straps or thin plastic mesh to hold the insulation back: staple to the frames on each side of the cavity, then fit the fabric over that.

4. How do you know how many material you need in order to avoid humidity? If I understand correctly, a single frame window will have to control humidity only in the window cavity... With decoupled window we must control humidity of the whole wall?

It's the same in both cases: there is practically no air movement inside the wall, so you only need to deal with the humidity trapped in the actual window cavity, and a little extra out to the sides. Depending on the type of desiccant that you use, there are equations for calculating how much you need, based on the volume of air trapped in the cavity.

5. How do you place this material into the wall or window?

Some type of tray along the bottom edge of the window cavity, just under the fabric.


- Stuart -

[Gregwor]

3. Is this correct, how would you hold the mineral wool to the sides of the window, top and bottom?

As Stuart said, rigid fibreglass insulation (like OC703) cut precisely to size and pressure fit will probably do the trick. But, to ensure no sagging, you can put your top in first and then wedge your side pieces in next which will help hold the ends of the top piece up in place. Then finally, put your lower piece in. You could use a finishing nail toe nailed through the center of the top piece into the frame to ensure the piece will never sag. Use a marker the same colour as your fabric and then just put the nail deep enough that you can pull the fabric over top of it.

4. How do you know how many material you need in order to avoid humidity?

This is a question I never got a solid answer on myself. If you check out my personal design thread:

http://www.johnlsayers.com/phpBB2/viewt ... 6&start=90

I had conflicting calculations with Stuart. Maybe Stuart or someone can clarify. Either way, hopefully the thread I linked helps you calculate the amount you need.

5. How do you place this material into the wall or window?

What I plan to do with mine is just remove the required amount of insulation from the bottom section of my window cavity and set the desiccant in the voids and cover it all with fabric.

Remember to active the desiccant before you put it in!

Greg

[memocn59]

There are several methods, but the easiest is to use sem-rigid insulation in that area, cut to the same size as the gap, and wrap it with the fabric. Then just press it into place, and perhaps put a dab of glue on just ONE edge, to make sure that it stays on place. Another option is to use strips of packaging straps or thin plastic mesh to hold the insulation back: staple to the frames on each side of the cavity, then fit the fabric over that.

I´m using mineral wool of 3lbs density... From what I understand this mineral wool will be trapped between the two leaves by compressing a little the mineral wool... Wouldn´t this somehow couple my wall leaves?
If so... any recommendation to avoid sound or vibration transfer by the mineral wool from wall to wall?

[Soundman2020]

trapped between the two leaves by compressing a little the mineral wool...

No. Don't compress it. Just lay it in to the correct depth. If the gap is 4", then use 4" of insulation. In teh worst case, you could compress it just slightly, but no more than about 10%. However, try to avoid that.

- Stuart -

[memocn59]

Guys thank you for so much advice… I feel much more confident with each new advice. Now onto some questions regarding acoustic Windows:

I have a company to build my acoustic window but for what I can see, companies here I mexico take the style of "I think that would be enough" rather tan using proper calculations and theory. Well, at least they are willing to take advice from me regarding the design, so I have these next questions:


1. Some acoustic Windows have angled glass and I have Heard some benefits of it, could you please clarify these statements?:

a. Angled Windows do not provide better soundproof. Maybe even worse because of the air space loss.
b. Angled windows help with standing waves inside the window. If true how will these affect perfomance of the window?
c. Angled windows will help with light reflection and sound reflections (this would be good to reflect to the ceiling since I´m planing to have absorbing panels there)


2. My provider suggest two double glass leaf but each double window with a glass separator of 12mm. So from what I understand this would be like a 4 leaf system...
Laminated glass (6+3), 12 mm airgap, 6 mm glass ------ 20 cm airgap ----- 9 mm glass, 12 mm airgap, 6mm glass
From what I have learned in this forum, those 12mm airgaps are not desirable and we should obtain better soundproofing by eliminating 12mm airgaps and by that having two 15mm glass leafs and a single 20 cm airgap... Am I correct?


3. Regarding glass thickness:
a. I have read that one must have different glass thickness... How much difference is desire? In my case we have two equal glasses (2x 15mm). The only difference is one of them is laminated. Is this enough of a difference?
b. Since I have one leaf laminated and the other not... Is it preferable to have both leaves laminated?

4. How valuable is airspace for my window soundproof? Should I sacrifice space for inclination or otherwise? I think my priority is soundproofing but maybe I´m not too consciuos of the importance of the other issues not managed by having two paralel vertical glazes.

5. My wall leafs if brickwall 15cm thick and a triple 5/8 gypsum attached to 2x6 filled with 6 inches of 3lbs mineral wool and a 10 cm aispace between studs and brickwall... Total wall widht is about 40cm. It seems that matching the density of a brickwall with glass is almost impossible, i think this is only practical for worldclass studios. However, what are your thoughts on 6+3(laminated)+6 (total 15 mm laminated) for the brickwall side which will be the live room side and the control room will be a 9+6 mm.

Since I know this is too dificult I´m planning on compensate with airgap... That´s the reason for my 40 cm wall... Is there any trick to improve soundproofing of a window whem you have a limit of thickness? or, do you recommend any glass thickness? It would be great to be able to record drums


6. My provider tend to offer me for example 6mm+3mm glass for a total of 9mm glass. But basically they are using different pieces of glass together in order to obtain a piece that is more thick. Something like what we do with the layers of gypsum board. My question is, does this function the same? having 3 glasses together 3+6+6 would equal a single pane of 15mm?


Thank u very much for all your help. I´m planning to ask my provider to follow the Gregwor´s desing =)