John Sayers' Recording Studio Design Forum Archive

Hey Everyone,

First time posting here, but long-time stalker

I'm at the planning stage of my first studio build, and wanted to start asking for some advice to form more solid ideas.

The build will take place in an old farm out-building. I'll do some slight alterations to it - extending what will be the live room slightly. I've attached a Sketchup image (AerialShell.jpg) of what the shell will look like after this is done.
What will eventually be the control room is a 5.17m x 3.73m room, with stone & cement walls. These are thick, about 75cm. In the image I've included stud wall on three sides, 10cm from the outer leaf. The fourth side will be the outer leaf of my live room, so remains bare for now. This will most likely need covering when we come to acoustic treatment. The floor is poured cement.

The live room shell is a 6.26m x 4.70m room with walls of hollow cement blocks. As I haven't done the alterations I mentioned yet, I could probably extend this to be a 6.26m x 5.00m room if that would help. The floor is also poured cement.

The two floors are at different heights; the live room space is about 1 metre lower than control room.

The roof needs to be replaced. This will be a flat roof, kept as simple as possible. Unfortunately I may be limited on height. Worst-case scenario is 2.3m in the live room (floor to ceiling), with a little more leeway in the control room, more like 2.6m

With the current plan one would have to go outside to get from one room to the other. It's not ideal, but it might keep costs down. Open to suggestions here though

The goal of this studio is to design and build a space where we can track a band live. I'm not really interested in building a vocal booth. I'd like to get a good-sounding live room, and as accurate a control room as is possible with the space I have. I'm also keen to build it around an analogue desk - a Midas XL200, hence the big bugger in the SketchUp image!

In terms of isolation: Noise coming shouldn't be a huge issue I think. The nearest road is 30 meters away from the control room door, on the other side of the house. Noise from the studio may be more problematic. Our house is 6 metres away, but more importantly, we let out part of our house to some friends, and that part is 8 metres away. I'll be doing some propagation testing this weekend and will come back with results.

The aim is to do the structural changes starting in April 2017, and continue with the build throughout the summer.

Ideal budget is under €4000, self build, all-in. Would love to hear if you think this is realistic.

For now, I have some questions:

1. Control room orientation - Am I right in thinking the pictured arrangement is the best orientation? I figure it's too shallow the other way.

2. Do the window to the right of the listening position and the door to the left cause large problems? I know I'm aiming for a symmetrical room. Can I compensate with acoustic treatment and/or changing the angles of the stud walls? I notice in John's plan (below) symmetry isn't adhered to strictly.

3. In terms of the live room shape, I guess I want to aim for non-parallel walls and as big an air-gap as possible between the outer cement block leaf and the new stud-walls. I am thinking of shooting for something like John's Garage Studio 2. In fact both rooms in this design seem like they could work for my spaces. My only worry is ceiling height. Do I have enough?
Very early stages, I know, but any comments or suggestions welcomed. I'd like to do this right, despite the low budget!

On a more general note, thanks to John & the rest of the contributors for making this such an invaluable resource, it's been a joy to trawl through!

Rory.

Hi there Rory, and Welcome!!

My response is a bit late! Busy times... but hopefully it is still useful!

What will eventually be the control room is a 5.17m x 3.73m room, with stone & cement walls. These are thick, about 75cm

That's pretty good! You should be getting excellent isolation from that already.

In the image I've included stud wall on three sides, 10cm from the outer leaf.

Great! From the diagram, it looks like you are planning to do that inside-out?

The fourth side will be the outer leaf of my live room, so remains bare for now. This will most likely need covering when we come to acoustic treatment.

Not sure I understand... if there is no wall on that side, then you don't have a room! Are you planning to build a wall there at some point? I sure hope so! You can't build an isolation shell with just three sides. That would be like trying to build an aquarium with glass on only three sides....

With the current plan one would have to go outside to get from one room to the other. It's not ideal, but it might keep costs down. Open to suggestions here though

I'm wondering about that as well! Why is not possible to move between the rooms? From the diagram, there doesn't seem to be any reason at all why you can't build your two-leaf wall across there, put some doors in it, and put some steps going down into the LR. Why is that not feasible? Some type of local building code problem? It's not that hard to chop a hole through a concrete wall and put a door way in. OK, so it's not easy either, but it sure beats the hassle of NOT having an access path between CR and LR.

and as accurate a control room as is possible with the space I have.

Search for the document ITU BS.1116-2. That's the spec you should be aiming for. It lays out all the parameters that you'll need to hit to have a good control room.

I'm also keen to build it around an analogue desk - a Midas XL200, hence the big bugger in the SketchUp image!

Big console in a small room? That's going to be a problem. Large objects in small rooms wreak havoc on the acoustics. I'm not saying it's impossible: just that it creates a whole new bunch of challenges that you'll have to deal with. The acoustic treatment at the front end of your rooms is going to be necessarily complex, and probably expensive to do right. You pretty much have no option but to flush-mount ("soffit mount") your speakers, which is a good thing by the way! But it does add to the complexity.

The aim is to do the structural changes starting in April 2017,

Great! That gives you four months to do the design. That's about how ling it takes normally, so you should be fine there.

Ideal budget is under €4000,

Ummmmm.... there's your first problem, and it's a big one! You have nearly 50m2 of floor area, you have structural issues to deal with, you have a complex acoustic challenge at the front end of your CR, you have a difference in floor heights to deal with, and you haven't even mentioned doors, windows or the "elephant in the room": HVAC. 4k is not going to do this. That's just €80 per square meter. Sorry, but I have bad news for you. My customers in the UK who have built studios from the ground up tell me that construction costs for that type of studio are around € 1000 per square meter, give or take a couple of hundred. You are not doing a ground-up build, so your costs won't be anywhere near that much, but they will certainly be a lot higher than 80/m2. Just the HVAC system alone is going to blow half your entire budget, easily, and who knows how much its going to cost to replace the roof. At a very rough guess, for what you want to do I'd be thinking of a budget three to four times what you are talking about. I think you need to seriously re-consider either your budget, or your plans.

1. Control room orientation - Am I right in thinking the pictured arrangement is the best orientation? I figure it's too shallow the other way.

correct!

2. Do the window to the right of the listening position and the door to the left cause large problems?

No. They are both behind your first reflection points, so they won't be an issue from that point of view. And assuming that both the door and window are built properly, their acoustic properties won't be too different. If you really wanted to get the sounding identical, then put a window in the door as well.

I notice in John's plan (below) symmetry isn't adhered to strictly.

I don't agree: the front half of that control room looks to be perfectly symmetrical to me. Please point out the area that you think is not symmetrical. The bench is not an issue, as it is way below the speaker and head height, and is not a reflection path. It's also mostly behind the mic position.

3. In terms of the live room shape, I guess I want to aim for non-parallel

Not necessary. That's a myth, actually. Splayed walls in a live room can indeed help to control things like flutter echo, but those can be dealt with very efficiently with simple treatment. You'd need to angle the walls at least 12° to have an effect, and that wastes a LOT of space.

and as big an air-gap as possible between the outer cement block leaf and the new stud-walls.

You don't need a big air gap, since you already have concrete walls all around, so you are already getting decent isolation:: You have the luxury of keeping your air gap smaller than for most people. The minimum is around 10 cm, so if you are building your walls conventionally, then you could leave a framing gap of just 1cm or so.

In fact both rooms in this design seem like they could work for my spaces. My only worry is ceiling height. Do I have enough?

It's not ideal, but it's enough, I would try to get more on the LR side: The CR is fine with a lower ceiling, but the LR really needs more height. Drums and many other instruments just don't' sound good in rooms with low ceilings.

Very early stages, I know, but any comments or suggestions welcomed. I'd like to do this right, despite the low budget!

I just don't see you doing all that on such a low budget. Sorry. You MIGHT be able to do the CR for that, as long as you don't need to replace the roof of do something else fancy like that. Here's an idea: all a couple of local building contractors, and ask for their quite for replacing 50 m2 of flat roofing...

- Stuart -

Stuart, thanks so much for your reply; all helpful points.

To clear up a few things, and answer some of your queries -

I can't find a good explanation on the "inside-out" technique, but my wall construction from outside to inside looks like: Existing wall-air-stud/insulation-plasterboard-plaster. I didn't have the plasterboard in the image; maybe that's where I'm misleading you! Updated pic attached here. If there's a better way to do this please let me know. Re: room with no walls! -

Not sure I understand... if there is no wall on that side, then you don't have a room! Are you planning to build a wall there at some point? I sure hope so! You can't build an isolation shell with just three sides. That would be like trying to build an aquarium with glass on only three sides....

Didn't explain that very well did I?! Slightly revised plan: There is already a thick wall constructed between the two spaces (leaf 1). I now plan to construct stud walls to enclose the CR (leaf 2), as shown in the image above. My meaning was, if I construct another stud wall on the LR side of the existing wall (leaf 1), I'll be into a 3-leaf system, which will bring DOWN my isolation. So my LR has three stud walls, and one concrete wall. Does that make sense? Images here: Re: Door between rooms -

It's not that hard to chop a hole through a concrete wall and put a door way in. OK, so it's not easy either, but it sure beats the hassle of NOT having an access path between CR and LR.

On further thought, you're totally right here. I’m trying to figure out if this would be best as a single doorway and a window, or whether to use sliding doors instead. I’m leaning toward sliding doors as I can pick two of these up fairly cheaply second hand. Then again it does add a big reflective surface in a small room (bad).

Regarding the desk, I see your point. It may be possible to reduce it to a 24-channel version, which considerably reduces the size of the reflective surface. Either that or I could choose a smaller console.

Re: John S's drawing:

I don't agree: the front half of that control room looks to be perfectly symmetrical to me. Please point out the area that you think is not symmetrical. The bench is not an issue, as it is way below the speaker and head height, and is not a reflection path. It's also mostly behind the mic position.

Indeed! I was referring to the rear half of the CR! I assume by what you say that this isn't so much of an issue?

Point taken about the myth of non-parallel walls, thank you!

Re: ceiling height - I might be able to get more height if I can reduce the slant of the flat roof. I'll have to check regs.

Budget-wise, I thought I was a little way off alright, though I missed out a few details, which should bring costs down considerably.
a. The roofing costs are separate, and not to be included in this amount
b. Building materials will be obtained at wholesale cost (nice to have family in construction!)
...regardless, as you say, some re-assessment is needed, which I'm looking at currently.

A couple more questions, if that's ok?

1. If I’m adding a door to connect LR & CR, I want to leave enough space between the door frame and the back wall for acoustic treatment. I know I want as much as possible, but how much, do you think, is reasonable in the space I have?

2. Are glass doors in such a small control room a bad idea? I’m worried about adding more very reflective surfaces...

3. You mention that the front end of the CR is going to be necessarily complex and probably expensive. Can you elaborate on this? What kind of treatment am I looking at? You mentioned soffit-mounting speakers; I have Yamaha HS50s. What goes between the soffit towers?

4. What type of insulation should I be using for my walls? I’m struggling to find answers which I can apply to buying in Ireland. What are the crucial characteristics? Will ordinary Rockwool RW3 do the trick?

5. Following on, I’m curious about how to secure the insulation in the walls so it sits up against the plasterboard? How do I stop the insulation from sagging down or falling away from the rear of the plasterboard (unless I’m using rigid panels)?

6. With my LR, how do I fasten my wall studs to the existing concrete wall where they meet? I obviously want to reduce transmission of sound, but on the other hand, the studs need structural integrity!

That’s as far along as I am for now. Not rushing for that April start deadline; a solid plan is more important! Also, this is all hugely helpful in getting a more realistic budget together, so thank you again for your patience and time!

Rory.

Bump.

I can't find a good explanation on the "inside-out" technique,

Building a wall or ceiling "inside out" means that the studs face the room, and the drywall faces the wall cavity, as opposed to "conventional" construction, where the studs face the cavity and the drywall faces the room. The advantage to "inside out" construction is that you have the space between the studs, all around the room, available for your room treatment. With a conventional wall, you have to hang acoustic treatment on the front of the wall, sticking out into the room, but with inside-out all the treatment can be "inside" the wall, just covered with a fabric finish across the front of the studs. This also means that the room is bigger than it looks, acoustically. There are some very real advantages to this techinque.

Your original image seemed to show this, since you did not put the drywall (plasterboard) in it.

My meaning was, if I construct another stud wall on the LR side of the existing wall (leaf 1), I'll be into a 3-leaf system, which will bring DOWN my isolation. So my LR has three stud walls, and one concrete wall. Does that make sense? Images here:

Weeelllllll.... sort of but not really! Yes, technically it would be a 3-leaf wall, but if that "middle" wall is massive concrete block (as it seems to be), with a huge hole in it where the doorway / window passes through, then you don't have a problem, and building it as 3-leaf would be the best way to do that. 3-leaf is only a problem when you have light-weight leaves with small air gaps, and all leaves fully sealed. In any 3-leaf situation, you can compensate for the higher resonant frequency and lower isolation by increasing the mass on all three leaves, and increasing the size of the air gap, such that the system is re-tuned to where it would have been if it were only two leaves. And the most efficient arrangement is where the middle leaf has at least the same mass as the other two leaves combined. In your case, the middle leaf (concrete block) has much, much higher mass than either of the other two leaves, plus it is not sealed, due to the massive hole for the doorway/window. You will not have a 3-leaf problem like that. Yes it is still 3-leaf, but no it will not be an issue.

I’m trying to figure out if this would be best as a single doorway and a window, or whether to use sliding doors instead. I’m leaning toward sliding doors as I can pick two of these up fairly cheaply second hand. Then again it does add a big reflective surface in a small room (bad).

I would go with the sliding glass. It makes both rooms look more "airy", and improves sight-lines between them. The reflective of glass is not far different from the reactivity of drywall, across pretty much all of the spectrum, so that's not an issue either! As long as you plan the location well, so that the reflections are not going to be a problem at the mix position, then you will be fine.

Indeed! I was referring to the rear half of the CR! I assume by what you say that this isn't so much of an issue?

Right! symmetry is critical in the front part of the room (the part between the front wall and your head), since that is the path that the direct sound takes from the speakers to your ears. That part must be symmetrical to ensure that your ears are hearing both sides exactly the same. The path must be as clean and perfect as possible. Once the sound has gone past your ears, what you need is attenuation. The rear half of the room must reduce the level of the rear reflections and the reverberant field such that by the time it eventually gets back to your ears (after the Haas time, ideally) it is 20dB quieter than it was as it went past your ears, and it is much more diffuse. So symmetry is not so important in that region, as the sound field that you hear from it will be 100 times quieter, and delayed by at least 20 ms. If you can get symmetry in the back, that's great, but if not then it usually isn't a major problem. The most important goal for a control room is that you get the direct sound from the speakers straight to your ears, with no distortion, coloration, phasing, delays, intensity difference, or any other change. You want just the sound from the speakers, perfectly. If you achieve that, then the delayed, subdued reverberant field from behind is not going to affect your perception of the sound from the speakers.

1. If I’m adding a door to connect LR & CR, I want to leave enough space between the door frame and the back wall for acoustic treatment. I know I want as much as possible, but how much, do you think, is reasonable in the space I have?

You would need at least enough space to fit in superchunks in the rear corner, and for that room your superchunks will likely need to extent out around 36 inches from the corner, along both walls. If you can't afford that much, then as long as you have at least 24", you should be OK. So the edge of your door frame should be no closer than 24" to the rear corner, and 36" if you can afford the space and still get the door in such that it does not reach as far forward as your first reflection point on that side of the room.

As with most things in studio design, it's a balancing act to get doors and windows in the most useful place for practical purposes, while also keeping them in the best place for acoustics! You often have to compromise on one or the other...

2. Are glass doors in such a small control room a bad idea? I’m worried about adding more very reflective surfaces...

There should be no problem with that. As I mentioned above, glass is pretty much the same as drywall, in relation to relativity, across most of the spectrum. There are only minor differences, so that in itself is not usually an issue. It only becomes an issue if you need to put treatment on the same spot, for example at first reflection points. There's no problem with hanging a large absorptive panel in front of a drywall wall, but that doesn't look so good if you have to hang a panel in front of your window!

There are "tricks" for dealing with that too. On occasions I have run into that issue with rooms I'm designing, and usually it is possible to angle the glass or door a little, such that the reflections do not reach the mix position. I'm not talking about vertical angling (tilting the top of the window in or out), but rather angling the window or door from side to side, so that the left edge (when looking at the door or window straight on) is further into the room, or out of the room, than the right edge, thus forcing the reflections to take a different path. You often only need to put an small angle on there, just a few degrees, to make the reflections behave.

3. You mention that the front end of the CR is going to be necessarily complex and probably expensive. Can you elaborate on this? What kind of treatment am I looking at? You mentioned soffit-mounting speakers; I have Yamaha HS50s. What goes between the soffit towers?

The goal for the front half of the room is to make it disappear! Acoustically, I mean. You want to do your best such that it sounds like there is no front end... that the sound just sort of appears at your ears magically, out of nowhere, perfectly clean and pristine, exactly as it left the front face of the speakers. You want to prevent the front of the room from changing that sound path in any way at all. It should not add anything to the sound of the speakers, it should not take anything away from their sound, it should prevent any early reflections from getting to your ears, and it should pretend to be invisible, acoustically, as far as the direct sound is concerned. Of course, in the real world you can't make it invisible to the reverberant field in the room, nor to the low frequency modal response, but you can make it invisible in relation to the direct sound from the speakers. You do that b carefully angling surfaces at the front of the room to ensure that all early reflections are directed past your ears, such that the never reach your ears, and that all artifacts caused by the front wall are minimized. The very best possible way of doing that, is to flush-mount your speakers in angled panels that are part of the front wall, also known as "soffit mounting".

I have Yamaha HS50s

Not a problem! I used to think that rear-ported speakers could not be soffit mounted well... until I looked into it! There's no problem with that, as long as it is done properly. Take a look here: http://www.johnlsayers.com/phpBB2/viewt ... =2&t=20471 Those are Eve SC-407's. They have massive bass-reflex ports on the rear. As you can see, there is absolutely no issue at all with their performance, in those soffits. As long as you design the soffits to take that into account, there is no problem.

What goes between the soffit towers?

Whatever you want! In some cases, I have put doors or windows in there, in one or two cases I have made that into a storage area, or an equipment rack area (duly ventilated and covered, of course). In some cases I have made it absorptive, when the room has needed that. In some cases I have give it a strange angle, for strange reasons...

4. What type of insulation should I be using for my walls? I’m struggling to find answers which I can apply to buying in Ireland. What are the crucial characteristics? Will ordinary Rockwool RW3 do the trick?

The characteristic that matters is called "gas flow resistivity", but most manufacturers don't bother measuring that, or publishing it, since it isn't very important for the main purpose of insulation: thermal. It only matter for acoustics, and that's a secondary. lower priority, application. Fortunately, there's an proximate relationship between GFR and the density of each type of insulation, so it is possible to estimate the acoustic response as long as you know the type of insulation (what it is made from) and the density. If you use mineral wool insulation, then you need stuff that has a density of around 50 kg/m3. If you use fiberglass insulation, then you need stuff with a density of around 30 kg/m3.

5. Following on, I’m curious about how to secure the insulation in the walls so it sits up against the plasterboard? How do I stop the insulation from sagging down or falling away from the rear of the plasterboard (unless I’m using rigid panels)?

Impaling clips!

6. With my LR, how do I fasten my wall studs to the existing concrete wall where they meet?

You don't! There can be no connections between your inner-leaf and any other part of the building. The inner-leaf must be totall disconnected mechanically: it is built as a stand-alone structure.


- Stuart -

Stuart -

Thanks so much for your replies here, hugely helpful. Plans have changed, unfortunately, so I'm starting a new thread.

R