John Sayers' Recording Studio Design Forum Archive

Hi there,

I have some specific questions for you about speccing an entrance/exit door(s) for my one room detached garden studio, and also what to do about speccing a window for it too, that you can scroll down to below. But first, in accordance with forum rules, here is a quick overview about my build project ( hope this is enough detail for now btw):-

The goal is to build a detatched garden studio in which I can work. I make music and sound fx for video games and have for many years now worked from a spare bedroom. My wife and I had a baby son last year and so the time finally came to move my gear and working environment out to somewhere else. We live in the countryside and our garden backs onto a farmers field. The site is at the bottom of the garden and is 60 metres away from my house and either of my neighbours. Our builders dug the footings out last week. Yesterday the concrete foundations were poured.

My pimary goal for this building is that when I close the door I can set up a microphone in there, and record my voice, acoustic guitar, or foley sound fx work, without having to wait for the neighbours lawnmowing to stop, or the dog a few doors down to stop barking, or occasional vehicles going up the road (80 metres away) to pass by etc.

This is far more important to me than my own sound levels escaping. I monitor so quietly that it honestly wont be a problem (and never has been all these years working in a domestic house). So I haven't measured my sound levels and I hope you will forgive that. It really is a case of keeping exterior environmental noise out of my microphones- thats the main goal of this studio build.

Details:- The building will measure 7.7m x 5.5m. Internal ceiling height will be 3m, and above that will be a 40 degree pitched room (total building height is 5.3m). Outer walls will be high density blocks laid flat (those things are heavy!). Roof will be clad in pan tiles. The walls and ceiling of the Inner 'room' will be decoupled from the block work outer and concrete floor by means of neoprene blocks and resiliant bar. The inner walls will be timber stud with rockwool infill followed by 1 layer of sound board and a final layer of plasterboard. The Ceiling will be the same as the walls but with even more mineral wool above it. The floor will be the concrete slab (we'll probably put a level screed on top of this) and I'm not planning on laying any board or wood on top of this. I guess I can use rugs if I need to. My budget is tight. The whole build is estimated to come in at somewhere between £16000 and £20000. Our builder (Dave) is a top bloke and one of the good guys, diligent and takes pride in what he does. However, he has never built a studio before....

So now we come to my immediate questions, and the first one is all about how I get in and out of this one room studio building. I need a door. I plan on having a two door system with one door and frame in the block work wall, and the second door and frame in the stud wall. That means the gap between them is merely the width of the wall cavity (which I think is 10cm).

Does that sound sensible? Can I use standard fire doors for these? Would I be better off building my own doors (like some of the mdf-layer ones I have seen in other posts here). If so then will a 'home made' mdf layer door withstand the damp and cold of the English weather?

By the way my budget is tight on this so if I could get my door(s) to come in (hung and furnished with seals, handles, closers etc) all told for between £500 and £750 I would be very happy.

Window: I hope to have a window to let in some daylight and give a nice view of the sheep in the farmers field. Should I ask the builder to make a bespoke window system with a pane of glass in both the inner stud and outer block wall? Or can I simply fit domestic UPVC double galzing windows (so again thats one in the stud wall and one in the block wall)? Should I specify a thickness and type of glass?

I plan to site the window behind my DAW desk so I'll have my monitor speakers either side of the window, and the door just behind and to the left of my desk so its still a good five metres away from the far end of the room where the microphones will be set up.

I know I haven't yet included as many details and pics as many of the excellent and interesting posts I have seen on here, but if you could recommend a few pointers on the doors and window to get me going I would be extremely grateful. I will endeavour to get more details and some pics up on here as work progesses.

Until then thanks a million for reading and for any advice you can give.

Best,
Al.

Hi Al, and welcome to the forum!

My pimary goal for this building is that when I close the door I can set up a microphone in there, and record my voice, acoustic guitar, or foley sound fx work,

Foley work requires fairly extreme isolation, beyond what you normally need in a typical live room, include very quite HVAC. Foley work is practically all recording very soft sounds that need to be greatly amplified for their final purpose, so a really, really quiet room is a necessity. If not, then when those soft footsteps in sand are amplified enough to fit into the final soundtrack, they will be accompanied by the thunderous roar of the ventilation system, and the whine of the fans on the equipment in the next room.

Good Foley stages also have very deep foundations, and very thick concrete slabs, to get a good "connection" to the earth, and at least some of the pits are formed into the floor surface: water pits, for example. So if your foundations are already poured, you might be a little late for doing that. I guess it all depends on how serious you are about your Foley work, to decide if you want to re-do that, or just live with what you have.

In any event, your room is going to need a much more rigorous design for the isolation, and careful attention to detail during the actual build.

It really is a case of keeping exterior environmental noise out of my microphones- thats the main goal of this studio build.

Yup! That's the challenge of a Foley studio...

The walls and ceiling of the Inner 'room' will be decoupled from the block work outer and concrete floor by means of neoprene blocks and resiliant bar. The inner walls will be timber stud with rockwool infill followed by 1 layer of sound board and a final layer of plasterboard.

OK, several issues there: If you have a separate stud frame for your inner leaf, then you do not also need the resilient channel. The separate frame has already decoupled your inner-leaf drywall from the outer-leaf, so there isn't much point in decoupling it again, with the RC. Second, there's also not much point to "floating" your wall on neoprene blocks, since the wall still has to be anchored to the floor somehow: usually with steel anchor bolts that bypass the neoprene anyway. It is possible to float a wall, but it's not quite as easy as just laying down some rubber and building a stud frame on it. There's a lot more to it than that. And third, there's no need to buy expensive proprietary drywall when plain old ordinary fire-rated drywall does the job just as well, and a lot cheaper. Rather, I would suggest that you spend the money you save there on a couple of cases of Green Glue, and put that between your two layers of 16mm drywall, since that stuff really does have very useful properties that will be of benefit to your build. Think of it this way: Mass is mass, and sound waves are not impressed by price tags: they wont stop any better just because you paid more per kilogram for your mass : all they see is the amount of mass per square meter of wall, and that's what they react to, regardless of how much it cost you to put it there. So you might as well go with the least expensive mass that will do the job.

The Ceiling will be the same as the walls but with even more mineral wool above it.

Why more wool? Wool does not isolate: the purpose of wool between the inner and outer leaf is to damp the various types of resonances that will be going on inside the wall cavity. It's good to have the wall cavity as full as possible, hopefully 100% (but not compressed), but adding more beyond that in the ceiling is probably not going to improve isolation.

The floor will be the concrete slab (we'll probably put a level screed on top of this)

Why? Ideally, for a Foley studio, the floor itself should be one very thick chunk of concrete, so it actually sounds like concrete when you walk on it: thin slabs don't sound convincing for Foley work.

My budget is tight. The whole build is estimated to come in at somewhere between £16000 and £20000.

I'm not sure what building costs are like where you live, but that sounds like a realistic number. Perhaps on the low side, but in the ball-park, I think.

Our builder (Dave) is a top bloke and one of the good guys, diligent and takes pride in what he does. However, he has never built a studio before....

"Diligent" and "takes pride in what he does" will go a long way towards getting over the hurdle of not having done this before. That's what the forum is meant for: to help out people who WANT to be helped, and are willing to put in the work that it takes to get there. There will be differences in the techniques from what he is used to doing, but as long as the studio is planned very carefully, with him involved in seeing that process as it unfolds, asking questions, and understanding why certain things are done certain ways, then he should be OK. The techniques are not difficult: just different. And if he already "gets it" in advance, then he'll do things the right way.

I need a door. I plan on having a two door system with one door and frame in the block work wall, and the second door and frame in the stud wall. That means the gap between them is merely the width of the wall cavity (which I think is 10cm).

That's the basic idea, yes, but where did you get the 10cm figure from? That might not be enough for a Foley stage. An isolation wall is a tuned system, and one of the parameters that go into tuning it, is the depth of the cavity. If the cavity is not deep enough for the amount of mass on each leaf, then the resonant frequency will be too high, and the wall will not isolate well for low frequencies... such as the distant rumble of a truck passing on that road, or a helicopter flying overhead somewhere, or thunder, rain, hail.... The wall has to be tuned for the purpose for which it is intended. 10cm might not be enough: did you do the math to come up with that?

Does that sound sensible? Can I use standard fire doors for these? Would I be better off building my own doors (like some of the mdf-layer ones I have seen in other posts here).

It's a Foley stage: it will need even more massive doors than the average studio. You might even want to consider using John Brandt's technique for the sand-filled door, or Rod Gervais technique for the lead-lined "Superdoor". Those doors will have to be really heavy, and have multiple seals on them, to provide the isolation that a Foley stage needs.

By the way my budget is tight on this so if I could get my door(s) to come in (hung and furnished with seals, handles, closers etc) all told for between £500 and £750 I would be very happy.

Hmmmm.... I suspect that you might not be "very happy" then. You might need to spend that much on each door...

Window: I hope to have a window to let in some daylight and give a nice view of the sheep in the farmers field. Should I ask the builder to make a bespoke window system with a pane of glass in both the inner stud and outer block wall?

Absolutely! For a Foley stage, you'll need very thick laminate glass for each leaf: The general idea is that the glass should roughly maintain the same surface density as the rest of the wall.

Or can I simply fit domestic UPVC double galzing windows (so again thats one in the stud wall and one in the block wall)?

Double glazing is not much use even in a normal studio, as the thin air gaps and light weight glass produce resonant frequencies that are just too high to be usable for the typical needs of a studio. But it is even more critical for a Foley stage, due to the high levels of isolation that you need, down to very low frequencies.

Should I specify a thickness and type of glass?

Yes. Based on the calculations for the desired MSM resonant frequency, and the desired level of isolation. I'm guessing probably 20mm thick, at least. Maybe more. And it should be laminate glass, too. Not just ordinary plate glass.

I plan to site the window behind my DAW desk so I'll have my monitor speakers either side of the window,

So this is going to be a single-room studio? No separate control room? That doesn't sound like a good idea for a Foley stage. The equipment will be too noisy. If you go that route, then you wont be able to use anything that has a fan in it, or a spinning hard disk, or anything else that moves. Your DAW will have to be completely silent: It will all have to be all solid-state and totally fanless. It might be an idea to consider putting a small control room in there, so you can keep your equipment out of the actual Foley area.

but if you could recommend a few pointers on the doors and window to get me going I would be extremely grateful.

Those will be critical points, for sure, and are always the weakest part of any isolation plan. The key is mass (lots of it) and seals (many of them). But there's one item that is even more critical, and you didn't mention it at all: Your HVAC system. For a Foley stage, the air velocity has to be lower even than for a typical studio, so your ducting has to be very large to allow for the volume of air that you need to move through there, and so do your silencers. They have to be rather extreme silencers, too, since they have to keep all that outside noise at bay. I'd say that your HVAC system design is going to be the hardest part of your design to get right. I would pay even more attention to that than to the doors and windows.

I must say, this is a fascinating project! I've always loved the "magic" of Foley, and there aren't that many people who want to build a Foley stage as part of their home studio, so this is an interesting change. You can bet that I'll be following your design and build thread avidly! It is something different, and a bit out of the ordinary.


- Stuart -

Hi Soundman,

Thank you so much for your swift and detailed reply! Thats given me a lot to think about and your advice about the walls and ceiling has really got me thinking about things again in those areas- I will come back with some more questions about those when I have done a bit more math.

However, I think this may change things a bit.....

I think I may have mislead you a bit by using the word 'Foley'. I am not building a specialised Foley Studio. My studio just needs to record acoustic guitar, vocals, and the occasional recording of some sound FX as per my description in my initial post. You are of course 100% correct in what you say about true foley studios requiring a lot of isolation, but that is not true for what I am hoping to achieve with my humble one room recording and mixing space.

Bearing in mind that I have been doing it this way for 15 years now in spare bedrooms of the houses I have lived in, and most of the games I have worked on have been fairly high profile titles, I seem to have gotten away with less than perfect working conditions all that time But that is because most of my sound fx work involves using sounds purchased from pre-recorded libraries, and so the work I do with actual microphones is only occasional.

I would, however, like to do more self-recorded sound fx work, and so not having to wait until my wife and baby are asleep, the birds have stopped tweeting outside, the tractor has stopped driving past the village (harvest time is a nightmare!!) etc before I can hit the Record button would be a huge bonus for me. But being in a one room building is fine. I can record without using devices that have fans in them too (although as I say this has not been an issue for me previously but I do have very quiet computers).

The rest of the time I will be composing, mixing, and occasionally recording my acoustic guitar or vocals (I also write songs) in there too. I compose a lot of music for my clients too you see.

So with all that extra information- do you think you would change your advice at all about what I need to do as regards the door and window?

Remember I'm 60m away from neighbours, and the (quiet village) road. I just need to stop the bird song, distant dog barks, distant traffic, neighbours mowing their lawns etc (there are a lot of elderly retired people here and they seem to like to mow their grass a lot!) , my kid playing in the back garden etc?

Thanks a million for your help!

Ahhhhh! So it's not going to be a true Foley stage after all? I was really looking forward to seeing that come together. I thought you were doing Foley for movies or something.

Anyway, yes that does change things: You wont need to go to the extremes I had envisioned, but rather just those of a typical home studio. In order to decide on the best way to build your place, I would suggest that you get out your sound level meter, and do some measurements at the location where you will be building this place. Pick a noisy time of day, when all of the sounds you suffer from are at their loudest, and measure the levels ("C" weighting, slow response), then take a look at the NC curves for studios and pick then one that most closely matches what you need: The difference between those two numbers is roughly the isolation that you'll need. Based on that, you can determine what the best materials and techniques are for building your place.

So with all that extra information- do you think you would change your advice at all about what I need to do as regards the door and window?

The concepts that I outlined above do not change: they still apply, just at a lower level. So you'll still need an decoupled two-leaf MSM isolation wall, two heavy doors back-to-back, two windows back-to-back, careful design of the HVAC system, etc. Those concepts are all still the same, just less intense, less extreme.

- Stuart -

Thanks again Soundman, and sorry to disappoint you about the Foley thing! Maybe one day I might have the money/space to set one up as it would be so cool!

I was able to borrow a sound level meter and take some readings today. My neighbour fired up his petrol engined lawnmower on the other side of the garden hedge to where my studio will be built. The sound meter read 66dB. I also measured the ambient sound (bird song and distant tractor in a nearby field) and the reading I got was 54dB. A bird scarer fired off a shot in a distant field and the reading was 61dB.

Does that help with narrowing down the spec for the doors and windows?

One more question:

then take a look at the NC curves for studios and pick then one that most closely matches what you need: The difference between those two numbers is roughly the isolation that you'll need

Please could you tell me where I should look for the NC curves you mentioned? Are they listed somewhere on this forum?

Thanks,
Al.

Thanks again Soundman, and sorry to disappoint you about the Foley thing!

Awwww geee... I was SO looking forward to seeing a Foley studio go up!

Please could you tell me where I should look for the NC curves you mentioned? Are they listed somewhere on this forum?

I'm sure they are on the forum somewhere, and in more than one place: the problem is finding them, as the search feature here doesn't allow searching for only two characters. But Google does....

https://www.google.cl/search?q=nc+curve ... 98&bih=597

Since you are in the UK, NR curves would probably be more appropriate: same concept, slightly different implementation. Curves are a bit steeper and a bit louder in the lows:

http://www.engineeringtoolbox.com/nc-no ... d_725.html
http://www.industrialacoustics.com/uk/r ... urves.html
http://www.industrialacoustics.com/uk/r ... urves.html

Basically, they are both "single number" curves that try to describe how quiet an environment is. If you google some more, you'll find descriptions of which curve is suitable for what types of buildings. You probably need something in the area of NR-20 to NR-30, give or take.


- Stuart -