Backyard Studio build (from ground up)

[jonosteer]

Hi everyone,

Firstly I want to say what a fantastic resource this forum is! It's invaluable to have an online platform to discover and converse with other people who are in this business of making nice recording and mixing spaces! Thanks John and co! I've already learnt so much, and I'm looking forward to learning much more!

About my project.....
I'm currently in the early stages of designing a small studio space which will be built from the ground up and will be located to the rear of a residential block in country Victoria (AUS). The space will primarily be used by me. I'm looking to build a nice sounding control room for mixing and production, and a small vocal/iso booth for overdubs. I'm also hoping to build a mezzanine bedroom above the studio for either myself or artists to use as accommodation for longer projects. I'm not super loud, but I want to be able to get away with monitoring/mixing at night so I'm aiming for as much isolation as possible within the size and budget constraints. I mostly mix and produce Pop, Indie/Folk and Electronic music. I'm utilising other spaces for tracking drums and ensemble performances, but am hoping this room will allow me to finish off my records with good quality vocal recordings and good acoustics for mixing!

About the block.....

Block of Land2.jpg

There are a few constraints with the property/design which I'll outline below.
The space we have to build within is only 5m x 5m (quite small!) and it is at the rear of the block adjoined by 3 other residential properties - 1 shed to the North, and a yard to the the East and South.
Due to building regulations we need to leave 150mm on either side for eaves/guttering so that leaves us with 4.7m x 4.85m to build within.
As we are building right to the boundary, we are unable to have windows on the rear or side walls.
The block has quite a steep slope from the rear of the block down towards the house. The top few metres has been dug out so that the space where the studio will sit is almost flat (approximately 1m drop at the front of the studio. Because of the slope and the depth of the block, getting a concrete slab poured in there is going to be quite difficult/expensive.

Budget.....
I'm hoping to complete the construction for under $30k (AUD). $25k would be ideal.
I have the benefit of having a builder in the family so there will be no labour costs for building and fitout.

Design.....(see attached)
The design I have so far is very basic. It includes an entrance/kitchenette with ladder to the mezzanine, a small iso booth and a control room.

Flat floor plan 1a.jpg

Flat floor plan 1b.jpg

Flat floor plan 1c.jpg

Control Room...
2.4m (h) x 3.1m (w) x 4.15m (l)
The dimensions of the room at it's widest points seem to be decent ratios based on my calculations.
I've opted to splay the walls at the front of the control room by 6 degrees purely to get some more space in the iso booth.
As the rear wall is the only one facing our property, it is the only wall which can have windows so the natural light will need to come mainly from these windows. The entrance also has to be on the same wall due to the position on the block. I plan on hanging the appropriate treatment between the two windows, and the yellow corners will be superchunk style traps which will go floor to ceiling.

I've opted for no soffit mounts for a couple of reasons.
1) I want the ability to change up monitors. I currently have Focal Twins, but I'm not certain they will be the best monitors for this space.
2) Although the building will be permanent, it might not be a recording studio forever, and I want the flexibility of being able to repurpose it as a granny flat/rumpus room without having to do too much rebuilding/deconstruction.

Iso Booth....
1.05m (avg w) x 2.4m (h) x 1.78m (l)
With this booth - I've tried to get decent dimensions but it's really hard in such a small space! The average dimensions give reasonable results in the room calculators I've tried, although I'm not sure how valid that is given that it's an irregular shape. I'm hoping to do something interesting with this room and have an openable/retractable roof which will open up to the pitched ceiling/mezzanine so i can have two different sounding options - but that may end up being a pipe dream.
The door into the booth is right in the first reflection zone, so it will need to be treated on both sides.

Wall construction...
In the design below, I've allowed for the following double leaf system Outside->In
Colorbond steel Cladding ->16mm Fyrchek -> Green Glue ->16mm Fyrchek ->90mm stud/acoutisorb3 -> 25mm Air gap ->90mm stud/acoutisorb2
->13mm Gyprock->Green Glue->13mm Gyprock-> (Internal room treatment TBC)

Walls.jpg

Flooring
As the pouring of a concrete slab is going to prove difficult and expensive due to the location, we are looking at building onto stumps.
I've had a look through the forum to see what alternatives there are to a concrete slab floor and haven't found much.
What is the best option? This is what I'd initially guessed (from the ground up).....
16mm Fyrchek ->Green Glue ->16mm Fyrchek-> Green Glue ->MDF ->Rubber stops ->90mm Studs/Acoustisorb2->MDF->Flooring.
With the external walls sitting on the lower layer of MDF and the internal walls on the upper layer.

Loft/Mezzanine...
Hasn't been designed yet, but it will basically just be a small bedroom. The ceiling will be pitched at the centre and will allow for a 2.5 metre clearance at the apex.
The floor of the mezzanine will sit up on the external walls only, and will not contact the internal walls or studio ceiling.
The HVAC ducting and vents will go between the two layers. Design still to come!

Questions!!!!!

Overall
1) Am I crazy? Should I give up now and hire a professional?

Flooring
2) Are we asking for trouble building without concrete on stumps?
3) Is there a better way to do it without a slab involved than the one mentioned above? (I'm sure there is )

Control room
4) Have I ruined a good ratio by splaying the walls? Or, could I potentially go even more than 6 degrees to give the iso booth even more space?
5) Is there any point in angling the ceiling too? I've read a few threads to say it's a bit hit/miss without professional calculations so it's probably not something worth doing? Would that be correct?

Entrance
6) The internal walls of this entrance are currently only single leaf as there isn't much space to play with. Can I put a double layer of Gyprock on these internal walls to create a bit more isolation or will that throw off the two leaf system used throughout the rest of the design? If adding the layer to the internal walls of the entrance is worth doing - how do we transition where it goes back to the double wall/air gap?

Iso Booth
7) The same question applies to the iso booth - as there's no room to do a double wall between the control room and booth, what is the best approach? A single wall with double layers of gyprock on either side? Given that the internal walls of the control room will be a hard surface, that leaves me a bit stumped. I would love to have the insulation exposed on the booth side so I don't have to take up even more space hanging treatment internally. What's the best approach here with such minimal space? I'm not as concerned about isolation between the booth and control room, but I do want the vocal booth to be workable and comfortable.

Doors
8 ) Are the internal doors ok to be just single doors if they are sealed well? Or should I be looking at putting double doors in?

General
9) One last option would be to remove the entrance completely and just continue the double walls around the control room and booth, with a double door entrance directly into to the control room (see option 2a below) but the downside of that would I'd have to have an external entrance to the mezzanine, and the kitchenette would need to be moved upstairs which is not ideal. If this method is going to achieve much better isolation, then I'd consider doing it.

Flat floor plan 2a 2014.jpg

That's about it for now. Thanks for reading through my post if you made it this far!
I'd appreciate any advice I can get - I'm very new to this whole thing.
Like many others - I have a dream, and just need a little assistance to make the dream a reality!!

Cheers!
Jono

[Soundman2020]

Hi there Jono, and Welcome to the forum!

Congrats on your plans for a ground-up build! Daring, but not as hard as it seems at first, and VERY rewarding once it is done.

I'm looking to build a nice sounding control room for mixing and production,

A control room should not "sound" like anything. It should sound like it is not there at all! It should sound perfectly neutral, neither adding to nor subtracting from the pure, clean sound coming out of the speakers. It's a tall order, but doable. Take a look at the ITU BS.1116-2 spec to see what that means in terms of actual acoustics. Here's a link to a thread about a room that does meet that spec, and in fact beats it in many aspects: www.johnlsayers.com/phpBB2/viewtopic.php?f=2&t=20471

I'm aiming for as much isolation as possible within the size and budget constraints

It would be better to put an actual number to that, in terms of how many decibels of isolation you need. Get a proper hand-held sound level meter, and use that to find out what that number is for you.

The space we have to build within is only 5m x 5m (quite small!)

Yep! Small it is. The spec I mentioned above says that the minimum floor area needed for a control room that performs like that, is 20m2. It is possible to do a control room in less area, yes, but the smaller it is, the harder it gets to treat it suitably, and the bigger the deviation will be with respect to "ideal". I have designed several rooms smaller than 20m2, and it can be done, but the smaller it is, the tougher it gets, and the more expensive it gets.

so that leaves us with 4.7m x 4.85m to build within.

Ouch! You are going to lose quiet a bit of that for isolation, so your room is going to be VERY small.

getting a concrete slab poured in there is going to be quite difficult/expensive.

Consider renting a concrete pump to do that. The truck parks outside in the street, and pours into the pump hopper. You have a pipe running from the pump to the actual site. It's MUCH better than having twenty hefty guys with wheelbarrows running back and forth! (Been there, done that....)

I'm hoping to complete the construction for under $30k (AUD). $25k would be ideal.

I have a few customers in Australia who have done similar projects, and it seem to be the consensus that building costs are in the region of AU$ 1,000 to 1,500 per square meter, so you are probably about right at 30k, but a bit on the low side.

The design I have so far is very basic. It includes an entrance/kitchenette with ladder to the mezzanine, a small iso booth and a control room.

Your ladder looks rather steep. There are limits on the angles that can be used for doing that. Better check your local building code, but to me that looks to be too steep.

As the rear wall is the only one facing our property, it is the only wall which can have windows so the natural light will need to come mainly from these windows.

Then turn the room around to face the other way! Those windows are taking up very valuable space where your rear-wall treatment will be needed, without any doubt. There's no problem with having a window at the front, between the speakers, but there's a big problem with having glass on the rear wall...

I plan on hanging the appropriate treatment between the two windows,

There is not enough room. Not by a long shot. In a room that small, the entire rear wall will have to be treatment.

I've opted for no soffit mounts for a couple of reasons.
1) I want the ability to change up monitors. I currently have Focal Twins, but I'm not certain they will be the best monitors for this space.

That's not a reason to reject soffits! Just design the soffits such that the speakers can easily be replaced. Take a look at this room, for example: http://www.johnlsayers.com/phpBB2/viewt ... =2&t=20471 It started out with a pair of Genelec 1031'sm and a couple of years later the owner switched those out for Eve SC-407's, which are much larger. In the original design I incorporated a slide-out "tray" system with exactly this scenario in mind. The owner swapped out those speakers for the new ones in a couple of hours.

Not a valid reason for rejecting soffits.

2) Although the building will be permanent, it might not be a recording studio forever, and I want the flexibility of being able to repurpose it as a granny flat/rumpus room without having to do too much rebuilding/deconstruction

Also not a valid reason for rejecting soffits! Just make the soffits as modules that are bolted in place, and can then be removed if you ever leave by unbolting them, loading them on a truck, and taking them to your new studio....

1.05m (avg w) x 2.4m (h) x 1.78m (l) ... With this booth - I've tried to get decent dimensions but it's really hard in such a small space!

How will you open the inner-leaf door? There's no space to do that. The door sweep will be directly across the area where you have your mic and talent set up, perhaps with video screen, music stand, headphones, etc. So each time someone needs to get in or out, you'll have to move everything out the way, just to open the door....

To be honest, with such a tiny floor area, I would skip the vocal booth and do all the recording of vocals right there, in the control room. Make that "booth" into a "machine room" closet, and also put your HVAC system in there, so there is nothing noisy inside the CR. Then you can also skip the splayed walls that are eating up a lot of space in the CR.

The average dimensions give reasonable results in the room calculators I've tried,

Which calculator? This is a vocal booth, not a control room, and it is minuscule, so room mode calculators would be no use at all. It's going to sound terrible, no matter how you treat it because it is basically nothing but a closet. Slightly bigger than a closet, but not by much. It will sound boxy and dull for anything you record in there, and will need a stack of treatment, Even then, it will sound boxy and dull. And I sure do hope you never have a claustrophobic musician! She'd run from there, screaming....

I'm hoping to do something interesting with this room and have an openable/retractable roof which will open up to the pitched ceiling/mezzanine so i can have two different sounding options - but that may end up being a pipe dream.

I'0m glad you used the word "pipe" in there, because that's exactly what you'd get! You'd change the sound from "boxy and dull", to "pipe-like, boxy and dull"...

The door into the booth is right in the first reflection zone, so it will need to be treated on both sides.

You are only showing one part of the door in your diagram, and no isolation. You need to add the other leaf to the booth, and the second door.

Colorbond steel Cladding ->16mm Fyrchek -> Green Glue ->16mm Fyrchek ->90mm stud/acoutisorb3 -> 25mm Air gap ->90mm stud/acoutisorb2 ->13mm Gyprock->Green Glue->13mm Gyprock-

To be honest, with such a tiny space, I would go for an inside-out wall for the CR, and use higher density materials, to save a few precious millimeters. Your priority should be to maximize the air volume inside the control room in whatever ways you can, and inside-out construction does that.

As the pouring of a concrete slab is going to prove difficult and expensive due to the location, we are looking at building onto stumps.

so you don't want good isolation? Mediocre isolation in the low mids, and poor isolation in the low end is fine?

I've had a look through the forum to see what alternatives there are to a concrete slab floor and haven't found much.

It's simple! Dig a hole, line it with gravel, put down your plastic, put in your rebar and mesh, and pour! It sounds big and scary to pour a monolithic slab foundation, but it's not as bad as it sounds at first. Rent the right equipment, get the right people, and it goes fast.

What is the best option? This is what I'd initially guessed (from the ground up).....
16mm Fyrchek ->Green Glue ->16mm Fyrchek-> Green Glue ->MDF ->Rubber stops ->90mm Studs/Acoustisorb2->MDF->Flooring.

Nope. The best option is: mother earth -- gravel -- plastic sheeting -- concrete with rebar and mesh. Done!

About your " rubber stops". It sounds like you are trying to float your floor, but you cannot actually do it like that. Take a look at IRC-766, IRC-802 and IRC-RR169 to understand why it is not possible, despite the claims of some manufacturers. Here's a thread that might help too: http://www.johnlsayers.com/phpBB2/viewt ... f=2&t=8173

Hasn't been designed yet, but it will basically just be a small bedroom. The ceiling will be pitched at the centre and will allow for a 2.5 metre clearance at the apex.

What is the heigh limit for outbuildings in your area? Most municipalities have limits not just on the footprint of outbuildings, but also the height: both the total height at the peak, and also the height at the eves, as well as usually provisions for not blocking the sunlight on adjacent properties. Have you looked into that?

What you propose is a very light-weight "floating" floor, that won't actually float at all! The ONLY way to float a floor is with mass. LOTS of mass. The inner-leaf floor needs to be very heavy. You can't get that amount of mass with wood (unless you make it a foot thick), but you can get it with concrete...

But you don't even need to do that. Floating a floor is a very, very complicated and expensive thing to do, and is not necessary in your case. All you need is a simple monolithic slab-on-grade. It can be done in a couple of days. The system you are talking about will take a couple of weeks to build, and that's after you spend another couple of weeks doing the math to ensure that the floor actually does float under all possible conditions.... which is next to impossible!

The HVAC ducting and vents will go between the two layers. Design still to come!

I'm not sure if you area ware of just hoe big your HVAC silencer boxes will be.... they are generally way too big to fit in between the walls. If you have very deep joists, you MIGHT be ale to get them in, but it won't be easy.

1) Am I crazy? Should I give up now and hire a professional?

Maybe both? Being crazy is the first requirement for building your own home studio: sane people would never consider doing that! But the outcome at the end of the process will allow you to recover your sanity, and get back the mundane task of making fabulous music. The insanity is temporary!

2) Are we asking for trouble building without concrete on stumps?

Yes.

4) Have I ruined a good ratio by splaying the walls? Or, could I potentially go even more than 6 degrees to give the iso booth even more space

I mentioned this above, but personally I would dump the idea of a vocal booth: there just isn't enough space to do a decent control room plus a booth in less that 23m2. I would make that into the "machine room / HVAC closet", and leave the CR rooms walls un-splayed, to maximize volume.

5) Is there any point in angling the ceiling too?

Not really. Leave it flat, as high as you can make it, and hang a cloud. Make the cloud hard-backed and angle that instead. That will accomplish roughly the same as the angled ceiling, but without the lost room volume.

I've read a few threads to say it's a bit hit/miss without professional calculations so it's probably not something worth doing? Would that be correct?

If you have the space, then it's not to hard to do, and there are several examples here on the forum of members who have done just that with good success. But for a small room like yours, it's best to maximize the room volume and achieve your acoustics in other ways.

6) The internal walls of this entrance are currently only single leaf as there isn't much space to play with.

That's not a part of the building that needs to be isolated anyway, so that's fine.

7) The same question applies to the iso booth - as there's no room to do a double wall between the control room and booth, what is the best approach?

The best approach is: Don't do it! At 1m wide, it's just too small to be usable as a vocal booth. That 1m does not even allow for treatment yet, and being so tiny means it is going to need a stack of treatment, just to make it "not-so-disgustingly-terrible". There won't be room to stand up in there, it will be claustrophobic, and it will sound ugly. As I mentioned above, your best plan is to do all your vocal recordings in the control room, which does have enough volume to be acoustically acceptable for that, and use that tiny space to put the noisy gear, such as the HVAC AHU, your DAW, and any toher gear that makes any noise at all.

A single wall with double layers of gyprock on either side? Given that the internal walls of the control room will be a hard surface, that leaves me a bit stumped. I would love to have the insulation exposed on the booth side so I don't have to take up even more space hanging treatment internally. What's the best approach here with such minimal space? I'm not as concerned about isolation between the booth and control room, but I do want the vocal booth to be workable and comfortable.

Yep! That is, indeed, the problem! And the solution is.... that there is no solution! There's a reason why you don't see such tiny vocal booths in professional studios... they just sound so bad that nobody would ever use them.

8 ) Are the internal doors ok to be just single doors if they are sealed well?

Depends on how much isolation you need, but in general the answer would be "No, that would not be enough".

Or should I be looking at putting double doors in?

Yup, very probably.

I'd appreciate any advice I can get - I'm very new to this whole thing.

- Stuart -

[jonosteer]

Thanks Stuart for the valuable advice!
I'm getting stuck back into the designing again after a busy few months of work. I think I'm slowly getting a better idea of what I can do with the small amount of space available!

personally I would dump the idea of a vocal booth: there just isn't enough space to do a decent control room plus a booth in less that 23m2. I would make that into the "machine room / HVAC closet", and leave the CR rooms walls un-splayed, to maximize volume.

I agree, seems much better to keep it as a one room design!
Here's a rough idea I have sketched up where the booth is removed, and half of the internal ceiling is also removed.

Studio Design 2.jpg

Studio Design 2A.jpg

Studio Design 2B.jpg

Vocals/piano would be tracked at the rear of the room where the ceiling is higher. I don't really need the entire floorspace on the level above so would prefer to maximise the volume of the room like you mentioned, plus I like the idea of having higher ceilings above the tracking/client area so the room feels and sounds a little bigger. How does one go about planning for the acoustics of such an irregular shape though? Am I better off to keep it rectangular and uniform?

Then turn the room around to face the other way! Those windows are taking up very valuable space where your rear-wall treatment will be needed, without any doubt. There's no problem with having a window at the front, between the speakers, but there's a big problem with having glass on the rear wall...

Done!
Soffits are in the plan now (borrowed another design for now but will finalise once I know which monitors are going in.

Make that "booth" into a "machine room" closet, and also put your HVAC system in there, so there is nothing noisy inside the CR. Then you can also skip the splayed walls that are eating up a lot of space in the CR.

Agreed! I've gotten rid of the splayed walls and the HVAC and machine cupboard can go in the entrance/kitchenette above head height.

To be honest, with such a tiny space, I would go for an inside-out wall for the CR, and use higher density materials, to save a few precious millimeters. Your priority should be to maximize the air volume inside the control room in whatever ways you can, and inside-out construction does that.

Agreed! Am planning to go inside-out now.

Consider renting a concrete pump to do that. The truck parks outside in the street, and pours into the pump hopper. You have a pipe running from the pump to the actual site. It's MUCH better than having twenty hefty guys with wheelbarrows running back and forth! (Been there, done that....)

Good advice again, thanks! Looking into the costs of the slab option. Due to the block of land having quite a steep incline, the amount of excavating needed to flatten out the ground is a factor too. Would a slab that sits flush with the earth at the rear of the building but is raised by stumps at the front be sufficient?

Would be keen to hear your thoughts on the half vaulted/half flat ceiling. Am I better off to forget the mezzanine entirely and just have a large open vaulted ceiling space (keeping in mind the overall external shape needs to stay the same)? I'd like to have room for some storage and a bed, but the functionality of the space as a studio is more important so if that's going to be miles better with no mezzanine then it's something I will consider.
For example...I could go with something like this if I can find a solution for the entrance

No mezz design 2.jpg

No mezz design 1.jpg

Thanks again for your assistance!

[Soundman2020]

Here's a rough idea I have sketched up where the booth is removed, and half of the internal ceiling is also removed.

That makes a lot more sense!

How does one go about planning for the acoustics of such an irregular shape though?

With great difficulty!

Actually, it's not too bad. You can't use regular room mode prediction software, of course, since the room needs to be a uniform rectangle for that to work, but that's not a big deal. You can estimate the performance of each section of the room.

One of the consequences of doing that is that you'll have two decay rates ("RT-60" times), one for the front section and one for the rear section. Or more accurately, the decay rate curve will change over time: it will start off a bit steeper (shorter decay) for the front, then you'll see that it changes angle, extending to a slower decay (for the rear). Once again, that's not too much of a problem, and can be beneficial if you do the treatment well.

I'd suggest "softening" the sudden transition that you have between front and back, in some manner, to avoid having a potentially large and possibly problematic impedance mismatch between the front and rear. There's a couple of ways you could do that.

This will be a bit strange, but I'm sort of liking it, as I think it can be good for you, overall. It will just need some careful acoustic design and treatment, to make it work well.

Am I better off to keep it rectangular and uniform?

I don't think so, no. In your case, you need all the volume you can get, and this is a good way of getting it. As long as you compensate for the shape with treatment (and shaping), I reckon this will be fine.

Soffits are in the plan now (borrowed another design for now but will finalise once I know which monitors are going in.

Agreed! I've gotten rid of the splayed walls and the HVAC and machine cupboard can go in the entrance/kitchenette above head height.

Agreed! Am planning to go inside-out now.

Good advice again, thanks! Looking into the costs of the slab option.

Slabs ain't cheap, so take a deep breath, and sit down firmly, before you look at the quotes...

Would a slab that sits flush with the earth at the rear of the building but is raised by stumps at the front be sufficient?

It's possible, but potentially can reduce your isolation. A full "slab on grade" (one that rests completely on the ground) is damped by the entire planet, which is hard to beat... If one end is raised up and has an air gap under it, then that part is not damped, and thus can vibrate, especially if there is impact noise getting into it (eg, piano...). It might be possible to use the dirt that you dig out of the low side to fill up the high side, so you can still have a "slab on grade", but that would need some heavy tamping to get it to behave. Slabs should normally be poured on undisturbed "native" or "virgin" earth. Earth that has been dug up, moved, piled, etc. can settle or sink, so "tamping" it firmly is usually necessary.

- Stuart -