Booth design questions?

[Paul Berton]

Hi I'm a newbie here!
I have converted my garage into a control room (5.8m long x 2.8m wide x 2.4m to 2.7m sloping ceiling) and now want to convert the adjoining tool shed in to a recording booth.
The control room wall construction is Cement fibre external cladding, 70 timber studs insulated, yellow tongue 19ml floorboards. This is sufficient isolation that I don't bother my neighbours but when I record vocals I sometimes have to redo takes as I live on a busy road.
The shed is on a concrete slab which is 15cm lower than the control room slab, so I will have a similar ceiling height to the control room.
There is a gap of 20cm between the end of the control room wall and the booth slab so I intend to utilise this to have 2 glass sliding doors between the control room & booth 20cm apart (slightly splayed).
The exterior dimensions of the shed (and slab) are 3.14m long x 3.1m wide. I will demolish the shed and build a new construction but I have to remain within these very tight external dimensions.
I will use the booth to record vocals & guitars mostly but also drums occasionally.
The dilemma I have is to make a room within a room I figure I will need 30cm thick walls which brings the room size down to very squeezey for a drum kit miced up.
I have a 10cm thick studio door which I am considering using in the booth to give me some storage and also a small bass trap above, between the door & the ceiling.
[attachment=0]booth staggered stud.pdf[/attachment]
Just wondering if anyone could advise -

1. walls 30cm thick will give me a booth approx 2.6 x be too small to record drums?
2. how thin could I make the wall using staggered stud type construction?
3. can staggered stud walls be splayed a la diagram 3?
4. is the door /storage in the booth a bad idea?

Sorry about the poor quality diagrams!
Thanks for any help!
Paul

[Gregwor]

Welcome to the forum!

Here are a few things to think about and consider.

-How much isolation do you need? Drums can hit 120dB. What is the maximum volume you're allowed to make at your property line legally? Subtract that number from 120dB and that's how much isolation you need. Chances are, unless you live out in the country and don't have neighbours anywhere near your rooms, you'll probably need to build a fully decoupled room in a room type design. As you're aware, that takes up quite a bit of space. I'd normally recommend building your inner leaf inside out, but you'll have to figure out the resonant frequency of your wall with different gaps between the walls to see if that is an option (to make sure you achieve your desired dB reduction at low troublesome frequencies). If you have to build it the normal way, you'll then have to apply a lot of treatment in the room (specifically having TONS of bass trapping and a ceiling that consists of broadband insulation). That will eat up into your space even more.
-Small rooms sound bad for pretty much everything, but specifically loud boomy drums. It could be decent for vocals or electric guitar amps.
-Your room dimensions are basically cubic. That's really really really really bad. It sounds like you can't make it bigger, and due to my first point, you don't have the options to make it smaller.
-You will need ventilation and heat. This will take up a lot of room and cost more money than you were probably anticipating to spend. The only saving grace is that the required HVAC silencer boxes you'd have to build could live in an area within your room which would force you to make your room more rectangular.
-Your diagrams show an entry door to your shed that doesn't make sense to me

I'm tired here, so that's all for now. Let us know what you think.

Greg

[Paul Berton]

Hi Greg

Thanks for your reply & the suggestion of building the inner room inside out!

Sorry about my poor quality diagrams! They represent the 3 designs I am trying to decide between.

If you look at the one called "booth staggered stud" that gives you a view of what the two rooms look like. My existing control room is at the bottom of this diagram - the control room has 2 doors, one that opens out & one that opens in.

I intend to have 2 sliding glass doors splayed approx 20 cm apart to go from the control room to the booth.

I have a 10cm thick studio door that I am thinking of using in the booth as a small storage space & also to break up the cube! I think that has confused you - it is not for access! I would use mesh at the back of this storage area so that I don't create a 3rd leaf. Or alternatively drop this storage idea.

I have recorded drums in my control room which as I described only has a single stud wall so I'm not concerned about bothering my neighbours. I live on a busy road near Sydney airport so I am more interested in keeping noise out!

I intend to have a split system ac unit. There is a Fujitsu model that has a super quiet mode (21dB).

So trying to find the best internal shape for this small area is my priority, isolation comes second!

Thanks again for your input!

Regards
Paul

[Gregwor]

Got it!

If room shape is your only real concern, here is your answer:

http://www.bobgolds.com/Mode/RoomModes.htm
or
https://amcoustics.com/tools/amroc

Those will tell you your best room dimensions. Rectangular rooms are the best in that you are able to mathematically (via these two links) determine the performance of the rooms. From there, you can add acoustic treatment. For such a small room like yours, don't get hung up on angled walls. You'll need all the space you can get for bass trapping every single corner in it.

Hope that helps!

Greg

[Soundman2020]

Those will tell you your best room dimensions. Rectangular rooms are the best ...

True! However ...

... 2.4m to 2.7m sloping ceiling

That sort of messes up the vertical dimension.... So only the axial mode calculations for the front/back and left/right axes will be valid, along with the tangentials that only involve those walls. The vertical axials will not be accurate, and neither will the tangentials that involve the ceiling floor. And none of the obliques will be accurate....


- Stuart -

[Paul Berton]

Thanks Greg for the link - that is incredibly useful!

And also Stuart for your reply, I have factored in that a flat ceiling is better! (The outside roof will still slope as I have to match it to the existing control room roof to comply with council.)

So after checking out the Bolt Area I figure I can just scrape in to the bottom left hand corner

H 2.4m x W 2.86m x L 3.6m = 24.7m3

The only way I can get that length will be by cutting the rear wall of my control room and losing 60cm.

A pain but do-able & it will probably make my control room sound better as at the moment the dimensions of it are Bolt's worst nightmare! My solution to my control room issues is that I use a combination of different monitors & headphones & finally take a single QSC10 outside and sit in my backyard to check my mixes!



The above dimensions will give me just 12cm for my side walls - the end wall could be thicker. 2 sets of sliding glass doors going in to the control room approx 20 cm apart.

So the only way I can figure that is (starting externally)

Outer wall
10mm fibro (I have to match the control room to comply with council)
4mm mass loaded vinyl
70mm stud
14mm air gap

Inner wall (inside out as suggested)
22mm Tongue & groove floor board - inner stud could be 70 or 90

120mm Total

120 x 2 = 240mm

So from my width of 310cm - 24cm = W 2.86m
I know this is not ideal as the air gap is tiny but it would at least get me in the bolt area.

There will be quite a gap above the ceiling as the booth slab is 15cm lower, or I could build a 15cm high drum riser to give me a consistent flat floor from the control room in to the booth. (Booth slab is 15cm lower than Control room slab).

Thanks again for your help!

[Soundman2020]

The only way I can get that length will be by cutting the rear wall of my control room and losing 60cm.

To be honest, I would not do that. With a small room, maximizing the total air volume is more important than hitting a "perfect" ratio. Ratios are important, yes, but not the only factor involved in designing a studio. Probably not even the most important! As long as your ratio is not bad (equal dimensions, one dimension a multiple of another, or withing 5% of another, etc.) then you are fine. There's no need to nudge and tweak things by millimeters to get them "perfect", because there's no such thing as a perfect ratio in a small room.

So go with the biggest dimension you can get, in all three directions. If that also means the ceiling has to slope, the so be it. As long as it slopes front-to-back (in other words, lowest over the speakers, highest at the back wall), then you are doing well.

Consider that the general "rule of thumb" for control rooms is that the volume should be at least 45m3, and the floor area at least 20m2. That does not mean that a smaller room is useless: just that it's harder to treat, and wont be as good as one that is larger. But it DOES mean that you should do whatever you can to increase the floor area and room volume, even if it means that your ratio is not ideal.

4mm mass loaded vinyl

So this is a high-budget studio? Money is not a problem? Plenty to throw around?

10mm fibro --- 70mm stud --- 14mm air gap --- Inner wall (inside out as suggested) --- 22mm Tongue & groove floor board - inner stud could be 70 or 90.

I'm assuming that "fibro" is "fiber cement board"?

I would do it a bit different:

10 mm fiber-cement board (Since that is apparently a code requirement)
12mm OSB
70 mm studs (or maybe 90mm? don't skimp here: your outer-leaf studs are holding up the entire building! Does your local code allow 70mm studs on load-bearing walls?)
(75 mm fiberglass insulation in stud bays)

10 mm gap (brings your total air gap up to almost the minimum recommended 100mm)

6mm fiber-cement board
12mm OSB
70mm studs

Total thickness of wall: 190 mm.

120mm Total

Ummmmm Nope! Not sure how you arrived at that, but your actual wall thickness as you described it would be 10+4+70+14+22+90 = 210mm

..

There will be quite a gap above the ceiling

Then make the ceiling higher! Increase room volume!


- Stuart -

[Paul Berton]

Hi Soundman 2020

Thanks for your input!

So to answer some of your questions...

My control room is 5.9 L x 2.84 W x 2.4 - 2.7 H (sloping ceiling) - almost a double cube so I figure cutting 60cm from the length would help both rooms sound better.

As far as designing / building my booth I am on a tight budget!

The loaded vinyl is $750 for 40 sq m - I have a friend who runs Pony Music one of Australia's largest rehearsal / recording studio complexes - they have built 2 complexes over the years. They have Metal bands rehearsing next to their recording studio so he knows about isolation. He tells me that mass loaded vinyl is excellent bang for buck when the issue is trying to keep my walls thin. he also tells me that a variety of different wall materials & thicknesses is also good.

Green glue is $1,000 for 40 sq me and my friend says he thinks loaded vinyl performs isolation better.

OSB is expensive in Australia - 12mm is approx $35 sq m
22mm Tongue & groove floorboard is approx $20 sq m - almost twice the mass of 12mm OSB

Wall measurement - I've taken Greg's suggestion so my inside wall will be inside out - less need for treatment, so it could be -

10+4+70- Outer wall

+14 +22 - air gap & T & G

= 120

That is the thickness of the wall

Then there is stud & insulation. 90

Total 210

I realise now that I need the 90 stud to be on the external wall & the 70 will be for the internal wall.

Hope that clarifies a few things!

Regards
Paul

[Soundman2020]

My control room is 5.9 L x 2.84 W x 2.4 - 2.7 H (sloping ceiling) - almost a double cube so I figure cutting 60cm from the length would help both rooms sound better.

And you would be wrong with that assumption! You are missing the point: I would suggest that you do some research on room modes and room ratios, as well as room volume, to find out why making a room smaller would not make it "sound better". Getting perfect modal response has very little to do with how the room "sounds". Room "sound" is achieve by treating the room accordingly, after it has been isolated, in order to meet the specs (such as ITU BS.1116-3m for example, for a control room). As I said, it is far better to maximize the room VOLUME, rather than go pointlessly chasing after the "room mode ghost" that doesn't even exist. With your current dimensions, you only have 16m2 of floor area: the minimum spec is 20m2. By chopping of another 60cm from the length, you make it ven smaller, bringing down the area to 15m2, and NOT noticeably improving the modal response! It still fails two out of the three critical tests used by the BBC (and others) to reject non-usable ratios.

Here's what your Bonello plot looks like for the smaller room:

PauleBerton-Smaller-Bonello.jpg

And for the larger room:

PauleBerton-Larger-Bonello.jpg

Do you see any major improvement there? I don't. A slight improvement in the mid range, which isn't even that important. On the other hand, by shrinking your room you shoe up the Schroeder frequency by 4%, from 125 to 130Hz, you reduce the total room volume by 12%, from 42 m3 to 38 m3, and your lowest modal support frequency jumps from 29 Hz to 32 Hz, which of course distorts the entire acoustic signature of the room further than it needs to be. 3 Hz doesn't sound like much, but it's huge down that low. That's two entire notes on the musical spectrum: going from A to C.

I'd like to hear your theory on how all of that would somehow make the room sound "better"!

Having said all that, I'm rather confused regarding which room we are talking about: Are you referring to your control room or your iso booth? IF we are talking about your iso booth, then why are you even concern about modal spread and room ratios?

As far as designing / building my booth I am on a tight budget!

Then why would you waste 750 bucks on stuff you don't need?

The loaded vinyl is $750 for 40 sq m - I have a friend who runs Pony Music one of Australia's largest rehearsal / recording studio complexes - they have built 2 complexes over the years. They have Metal bands rehearsing next to their recording studio so he knows about isolation.

Once again, you missed the point: I never said that MLV does not work! What I DID say is that it is extremely expensive, and you do not need to spend that much to get good isolation! Your pal at Pony Music can perhaps afford to splurge money on expensive, exotic materials: you can't.

Here's the issue, in very, very simple terms. This is the equation that defines how well a single-leaf barrier will stop sound, overall:

TL = 14.5 log (Ms * 0.205) + 23 dB

Where: M = Surface Mass in kg/m2

That's it. That is often referred to as the "Mass Law" equation, because it describes the law of physics that governs the simplest possible barrier to sound. ("TL" means "Transmission Loss", which is what acousticians call the ability of a wall to block sound.)

OK, so please show me in that equation, where I can plug in the price tag....

There is no variable in there that you can adjust to say "Well, my mass is REALLY expensive mass, so it MUST be better than any other mass"! The ONLY variable in that equation, is "mass". That's it. Price does not come into it.

You see, sound waves can't read, and they are not impressed by price tags. The are not elitist or snobbish at all! The ONLY thing that sound waves react to in a single-leaf barrier, is mass. Pure and simple. They have no way of "feeling" if your mass cost three times more than anybody else's mass. All they feel is the mass: More kilograms per square meter means they are more attenuated. Less mass means they are less attenuated. Price does not come into it. If a sound wave encounters a wall that has a surface mass of 30 kg/m2, it will be attenuated by exactly the same amount regardless of whether that wall is made from mud, sheetrock, OSB, MLV, steel, glass, gold, or titanium. The material itself is irrelevant: what matters is the mass, pure and simple.

Mass is mass. Sound waves don't care about anything else.

So that leads back to the basic question: If you are on a tight budget, then why would you pay MORE for your mass than you need to? Why would you spend mountains of cash on MLV that you don't need?

OK, so you might hear someone argue: "But, but, but... but MLV is not just ORDINARY mass it is LIMP mass, which is much better for attenuating low frequencies!" Sure it is! Exactly correct! ... Provided that you actually USE it as limp mass! In other words, configured as a membrane trap inside your wall. The way you are proposing to use it, is NOT as limp mass. You re using it as pure mass,not limp mass. In order to work as limp mass, it would have to hang freely in the middle of the wall cavity, sealed to the studs, with air and damping on both sides, and without touching the drywall, to do that. Good luck with achieving that on a low budget! Plus, if you do want to hang it as a limp mass membrane, you would need to make your walls a hell of a lot thicker to compensate for the three-leaf effect (look it up...), and you'd be getting into much more complicated math to figure out your isolation. Instead of the simple 2-leaf MSM equations, or the even simpler (but less encouraging) singe-leaf mass-law equation.

So once again, we get back to the point: you do NOT need to use exotic, expensive materials such as MLV, especially when you are on a tight budget, and especially when you are not even using it in the manner where it offers an advantage.

MLV does have its uses, but I VERY rarely use it in the studios I design and build. The cost is too high, compared to other materials, and it's a bitch to work with if you try to hang it as limp mass. The sensible thing to do, is to use the cheapest mass that will get the job done. In most places around the world, that is usually plain old drywall/sheetrock/plasterboard/gypsum board, or whatever else it might be called in different places.

He tells me that mass loaded vinyl is excellent bang for buck when the issue is trying to keep my walls thin.

The density of MLV is roughly 1500 kg/m3. The density of drywall is roughly 700 kg/m3. So yes, it's about twice as dense, and therefore you can make the leaf about half as thick. But you cannot use MLV on its own, due to its physical properties; it is fragile. If you lean on a wall made only of 4mm MLV, you will push right through! So you need to have some type of backing, such as drywall. If you use it along with drywall, then the 2:1 mass advantage is no longer there... It's more like 1.5 : 1. And considering that MLV is far more expensive than the same mass of drywall, there's no advantage at all.

On the other hand, aluminium has a density of 2800 kg/m3 (roughly twice as dense as MLV), steel has a density of around 7800 kg/m3 (5 times as dense as MLV), and lead has a density of around 12,500 kg/m3 (8 times as dense). So you could feasibly use lead foil just 0.5mm thick and get the same isolation you would from 4mm MLV (and lead is also limp mass, just like MLV). Or 1mm steel sheet, or 2mm aluminum sheet. Compare the prices of those options, to see how they stack up against drywall and MLV.

Usually when I need higher density to get thinner walls, I use fiber-cement board. It is a bit more dense than MLV, costs less (although still more expensive than drywall), and is easier to work with (as long as you are careful).

Now that you know all of the above, let's test what you have been told and see if it holds water: You were told that "MLV is better for thin walls, since it is higher density". True. But in the real world? You were planning to use 4mm MLV. That has the same mass as 8mm drywall. Do you REALLY want to spend all that extra money to save 4mm?

he also tells me that a variety of different wall materials & thicknesses is also good.

He's right, but also wrong! I get this argument a lot, but it's a myth. A true myth, but still a myth, if that makes sense! Yes, the impedance mismatch from having materials of different density inside your wall does have a positive effect on improving isolation. This is true. However, by doing that it obviously implies that one of the materials is of considerable LOWER density then the others! Right? So you have one layer of high density material, and one layer of low density material, and the interface between them causes an impedance mismatch that can attenuate SOME frequencies more effectively. True. ... HOWEVER, the frequencies that get the most benefit are high frequencies, which are not a problem anyway in a properly built wall, and here's the kicker: One of the materials is LOWER density than it needs to be, so it has to be THICKER to get back to the right total mass! Therefore, you entirely lost your advantage for thin walls. Oops! It turns out that it would have been better to just make the wall using two layers of the higher density material, rather one higher and one lower... You would get better isolation like that, down to lower frequencies. So what he said is true, but is also a myth. True because the underlying claim is correct, acoustically, but a myth because there's no real-world advantage to doing that.

Green glue is $1,000 for 40 sq me and my friend says he thinks loaded vinyl performs isolation better.

And he would be totally wrong about that! That's like saying "Steak costs 17 dollars per kilo, but rocks are better for building dams". So what? You are comparing entirely different things, that are used for two entirely different purposes! You don't eat rocks, you don't use steak to build dams! You don't use Green Glue to add mass to a wall, and you don't use MLV as constrained layer damping! The analogy is good, because there is no relationship at all between what MLV does for a wall, and what Green Glue does for a wall. MLV is mass, and it can also be used as limp mass. Period. Green Glue is a visco-elastic polymer that is never used as mass, and instead is intended to be used as constrained layer damping between layers of a wall leaf. Two totally different and unrelated principles. Green glue works by acting to damp certain types of resonance in the wall structure itself, notably the bending waves that run along the surface of the wall. MLV is just mass. Green Glue has some mass too, but that is not its purpose, and the mass is negligible becuase it is applied in a very thin layer, and the increase in surface density is tiny. What Green Glue does CANNOT by duplicated in any other way: not by construction glue, or caulk, or MLV, or carpet, or anything else. It is a very specific principle of acoustics that it uses, and it is very effective at doing that: It is great if you need to isolate low frequencies, and it does that in layer that is far, far thinner than MLV: maybe a mm or so. It is very effective.

Therefore, if you really do want the thinnest wall possible, and high isolation, forget MLV and go for two layers of drywall with Green Glue, or better still one layer of drywall plus one layer of fiber-cement board, with Green Glue. That would be about as thin as you can get, without going to things like steel plate or lead sheet.

It also does not cost one grand for 40m2...

OSB is expensive in Australia - 12mm is approx $35 sq m
22mm Tongue & groove floorboard is approx $20 sq m - almost twice the mass of 12mm OSB

I doubt that, since you are talking about thickness, not density, but even if it is true the T&G is MUCH harder to seal! You do know that you absolutely must seal the entire wall totally air-tight, right? Your pal did explain to you that there cannot be any gaps, cracks, holes or other penetrations where air can get through? Not even a single hairline crack? He did tell you about that? If you want to use T&G then you will need to carefully caulk every single joint between the planks, on both sides... It takes a lot of caulk to do that. Have you priced acoustic caulk yet? Not only that, but the result looks pretty ugly, where the caulk leaks out of the T&G joints...

Also, I'm not understanding you at all here: On the one hand you want to use an extremely expensive product to save 4mm of thickness on your wall, and on the other hand you want to use a cheap product to save money, but it is 10mm thicker! Huh? What am I not getting here? Why do you want so spend big money to save 4mm, while at the same time you want to save LESS money by WASTING 10mm? So which is it? Are you trying to save money or are you trying to get a thin wall? Because you are not doing either with your current plan...

This makes no sense. It seems to me that you are not thinking this thing through very well, and are basing your entire design on half-truths, myths, misunderstandings of the laws of physics, hearsay, and lack of understanding of how acoustic isolation works.

That is the thickness of the wall

No it isn't! That's the thickness of HALF the wall. That's only one leaf. An acoustic isolation wall is two leaves, decoupled. I think you did not understand what Greg was telling you. He did not tell you to put both leaves on the same stud frame....

Then there is stud & insulation. 90

Ummmm.... what's the purpose of that? So inside your completed room, after you fully build and finish the isolation shell, you then plan to put up yet another 90mm stud frame, with insulation in it, just sort of standing there on the floor, around the sides? Why? What do you think that would do for you? How would it work? In what way will insulation inside a stud frame without any mass or seal, improve the isolation? What equation should I use to calculate the effect that this would have?

Sorry if I'm coming across as harsh, or a bit sarcastic, and "in your face", but that's what we do around here: it gets your attention, and shows you exactly where you are going wrong. It's a not-too-gentle wake-up call. We don't beat around the bush, and we don't believe in PC at all. We just tell it like it is. If you are messing up, not understanding something, or being mislead, then we'll tell you exactly that: You are messing up. It might seem unfriendly, but it's actually the opposite: friends don't hide the truth from friends: they put it out on the table. "Tough love" some call it.

You obviously came to the forum because you trust us to give you solid advice on how to build your place right, and that's what we are doing. You have obviously asked others too, and they gave you some information but you didn't fully understand it, and that's OK! It is not a sin if you don't understand what someone told you, due to not yet having the necessary knowledge and understanding. Acoustics is complex, sound does not behave the way we expect it to, and it's tough to get your head around some of the concepts the first time you come across them. That's why you came here! Acoustics is confusing, and non-intuitive, and that's why the forum exists: to help people who don't get it yet, so they can understand as much as they need to understand, in order to design and build their studios.

So my suggestion would be that you do some more research here on the forum, to better understand the principles behind isolation, so you can build your booth better and get the level of isolation you need. What you should look for, is "fully decoupled two-leaf MSM isolation". Take a close look at that, redesign your wall so it costs half the price and works twice as well, and update your design here, so we can check it for you.


- Stuart -

[Paul Berton]

Thanks for your reply Stuart,

I tried to somehow highlight my responses but could not get bold print or different colour font to work.

so taking on board your suggestions -

1 I will not reduce the size of my control room

2 To be clear - I am building a booth that will be a de coupled room within a room

3 I will follow your build suggestions for the outer leaf & Greg's for the inner leaf. So -

10 mm fiber-cement board (Since that is apparently a code requirement) - I have to match the outer wall of my control room

Sarking paper for waterproofing

12mm OSB - I will use 13mm soundcheck gyprok (dry wall)

90mm studs - 75 mm fiberglass insulation in stud bays

10 mm gap (brings your total air gap up to almost the minimum recommended 100mm)

6mm fiber-cement board
Green glue
12mm OSB - I will use 19mm tongue & groove - sq m = T&G $14 / 13.8 kgs vs OSB 12mm $35 /7.6kg
70mm studs - with insulation



4 Quoting Greg "I'd normally recommend building your inner leaf inside out, but you'll have to figure out the resonant frequency of your wall with different gaps between the walls to see if that is an option (to make sure you achieve your desired dB reduction at low troublesome frequencies). If you have to build it the normal way, you'll then have to apply a lot of treatment in the room (specifically having TONS of bass trapping and a ceiling that consists of broadband insulation). That will eat up into your space even more."

Building the inner leaf inside out makes sense to me for the reasons Greg mentions.

4 Green glue $1000 for 40 sq m is what the Australian distributor quoted me, if you know where I can get it cheaper please let me know! I read elsewhere on this forum that using 50% of the recommended amount yields 70% result so that will be$500!

5 T&G is MUCH harder to seal! You do know that you absolutely must seal the entire wall totally air-tight, right? Your pal did explain to you that there cannot be any gaps, cracks, holes or other penetrations where air can get through? Not even a single hairline crack? He did tell you about that?

Yes I know I have to make it air tight

6 If you want to use T&G then you will need to carefully caulk every single joint between the planks, on both sides... It takes a lot of caulk to do that. Have you priced acoustic caulk yet?

According to others on this forum in Australia Sikaflex Pro is good - $17 per 300ml tube

7 Not only that, but the result looks pretty ugly, where the caulk leaks out of the T&G joints...

Following Greg's suggestion the wall will not be visible - I will use material to cover the insulation so from inside the booth you will see stud & material

Thanks for your input, I'm living & learning...
Regards
Paul

[Soundman2020]

I tried to somehow highlight my responses but could not get bold print or different colour font to work.

Click at one point in the text you want to highlight, so that it is shown with a blue background, then click on any of the buttons just above the top of the area where you type: The "B" is for Boldface, "i" is Italic, and "u" is Underline. Use the "quote" button if you want the text to appear in a quote box, like I did with your text, above.

1 I will not reduce the size of my control room

Smart move!

2 To be clear - I am building a booth that will be a de coupled room within a room

OK. Is the control room also the same?

4 Green glue $1000 for 40 sq m is what the Australian distributor quoted me, if you know where I can get it cheaper please let me know! I read elsewhere on this forum that using 50% of the recommended amount yields 70% result so that will be$500!

Right! But there are three different "dosages" that you can use. Of course, they want you to use the maximum, which is three tubes of Green Glue per 4' x 8' sheet of drywall. That does, indeed, give you the best performance. But reducing that to two tubes per sheet still gives you about 75% of the full coverage, and even at 1 tube per sheet, you are still getting quite good results. Green Glue Company themselves recommend those three possibilities, so that's an approved way of using the product. So you would only need one third of the amount the rep s trying to sell you...

According to others on this forum in Australia Sikaflex Pro is good - $17 per 300ml tube

There's a difference of $15 per m2 between the two options you mentioned, which is about the cost of one tube of that caulk. I'm betting you'd need a LOT more than one tube to seal the same area of T&G, as a full sheet of OSB!

Thanks for your input, I'm living & learning...

- Stuart -

[Paul Berton]

OK. Is the control room also the same?

Hi Stuart

No my control room is not a room within a room - it is a converted single car garage with cement fibre plank sheets, 90mm stud with insulation and a single layer of 22mm tongue & groove floor boards on the walls & ceiling. This is sufficient isolation that I can operate without bothering my neighbours, so I know my booth will have better isolation & even though it's tiny I have to make it work...trying to get it to sound as good as possible is more important to me than isolation.

Control room dimensions

5.9m L x 2.84 W x 2.4 - 2.7 H sloping ceiling (across the width of the room)

I know theses dimensions are a Bolt Area nightmare - almost a perfect double cube but I have to live & work with what I've got!

The external roof of my booth will have to match the same slope as my control room roof but the internal ceiling of the booth could be flat or sloping - any thoughts as to which would be better? (Flat would be just 2.4m Height)

I have attached 3 photos so you can see what the buildings look like.

Thanks again for your input!

Regards
Paul

[BruceMay]

Welcome to the forum buddy.

[Gregwor]

Sloped ceiling = more cubic feet = better.

Greg