New Music Room in UK south

Hi there Finally I am starting my studio build and I am feeling seriously out of my depth. I am a musician and music is what I understand, making buildings on the other hand is well outside my comfort zone. Luckily I am up for giving most things a go, as long as they are not too dangerous! I have been reading up about lots of stuff here on this amazing website and in various books, and I feel I have a sort of grip on some of the basics but so many questions and half digested concepts keep bubbling up that I think I need a little assistance to avoid making some expensive and serious mistakes. I am attempting to build a little music studio, (having acquired too many instruments to fit in my current music room) and I have started building a rear extension from scratch. As I am in the south UK (near Brighton) I am following some advice I read here about completing the basic structure and getting that signed off by buildings control first before converting into a studio later (what the building control officer doesn’t see will not disturb him!). So far things are going ok, even if almost my entire budget has been used up! I spend nearly a year digging in the back garden and then hired some builders to do the foundations brickwork and roof, and that is where I am up to now. The construction is all pretty basic - lots of concrete was poured into some holes and all over my back garden (a raft foundation) and then my brickies put up cavity walls (bricks on the outside and medium density blocks on the inside - 100mm insulation filled cavity) and a then big wooden rafters (trusses?) that support a warm flat roof covered with 3 layers of felt. There were some complications because I live on a slope so one wall is a metre underground and some heavy duty concrete blocks with rebar had to be used but I guess it is all good extra insulation. The room is now about 12.5m x 4.3m and I am planning a ‘room within a room’ design for sound insulation. Height is about 3.8m at the moment, I am hoping to keep finished height at no less than 3m. I haven’t finalised an internal design yet but I am thinking of a small control room (writing room) with a larger live room with a couple of smaller isolation rooms/booths. I know I will have some questions about that when the time comes. I plan to use the studio for recording mainly acoustic music of all types but my neighbours are quite close and I need to avoid any difficulties with them. I have to be able to have a loudish drummer bashing away for hours at a time without them getting annoyed. (Not very scientific I know but basically I will just get the best sound insulation I can realistically afford and live with it). There is just a metre of space between the outside walls of the studio and the fence to my neighbours gardens. One long wall is shared with my living room, but luckily this was the old outside wall so it is also a double brick wall with insulated cavity. As the floor is a big concrete slab and there are double brick walls it seems that the weakest point is always going to be the roof. I will put up 2x 12.5mm plasterboard underneath the beams and then the same again for the ‘room within a room’, hopefully that should be enough as I don’t know what else I can do. It isn’t going to be a full time recording studio as I will also use it for practicing and writing, rehearsing as well, but I hope to be able to make decent quality recordings for an acoustic jazz quartet or quintet. Budget? Hmm, I already used most of that …up to about £50k so far. Building is proving to be quite expensive but I am in it now and can’t stop. I can afford to spend about another £20k before things get really serious, but I was hoping to buy some monitors a new interface and a pair of decent mics out of that as well though;-) My estimates of costs have been fairly rough but I am still hopeful! I hope I haven’t missed any of the important details! I will post some photos of where I am at very soon, but I do have one important and pressing question… I am just preparing to screed the floor and have some concerns. I have got lots of polystyrene insulation (100mm) which will sit on the concrete slab with some heavy duty plastic (as a dpm) and am wondering what finish to put on this. I think I am allowed to use either 75mm of concrete screed or maybe 18mm chipbpoard (P5 tongue and groove). My concern is that the ‘room within a room’ is going to be HEAVY - studs, 2 layers of 12.5mm plasterboard 3m + high, roof beams (8x2, probably about 20 of them) and 2 more layers of plasterboard on the ceiling. All this has to sit an inch or so away from the existing walls (which would be right on the edge of the concrete screed), so I am worried about it compressing the polystyrene (which doesn’t seem that strong) and cracking the screed (or chipboard) and ultimately falling down and causing a disaster. I am wondering if I need to reinforce the edges in some way - some timber underneath maybe, or some medium reinforcing mesh in the screed, or both? Does anyone have an idea about the best way to proceed? I am guessing the concrete screed must be be better than the chipboard (also much more expensive and hard work)? Many thanks for any input Cheers David Please let know if I have missed anything.

Here are some photos of my build so far...

and some more...

and yet more photos ...

High there David, and Welcome! :)

I think I need a little assistance to avoid making some expensive and serious mistakes.

Looking at the photos, it might be a little late for that! :) There are a few things that you could have done differently to get a better studio, and to build it at lower cost, but it's too late for that now. Fortunately you can still get reasonably good results from where you are, as long as you don't need a lot of isolation.

completing the basic structure and getting that signed off by buildings control first before converting into a studio later

... except that you also did it without checking in here, to see if you were doing it the best way! :) And trying to fool the regulations that are there to protect you probably isn't a good idea either.

and then my brickies put up cavity walls

... which implies that you will end up with a 3-leaf system in the end...

and a then big wooden rafters

... which do not seem to be maintaining the needed surface density of the outer-leaf, assuming that you want to get decent isolation for your studio.

one wall is a metre underground and some heavy duty concrete blocks with rebar had to be used but I guess it is all good extra insulation.

That is good, yes, but I think you mean "isolation", not "insulation". :)

I am planning a ‘room within a room’ design for sound insulation

This is the part you didn't want to hear: you already have a "room within a room". You already have a two-leaf wall. Adding another leaf to that will create a 3-leaf system, which could potentially REDUCE the amount of isolation you get for low frequencies, unless it is carefully designed to avoid that.

I haven’t finalised an internal design yet but I am thinking of a small control room (writing room) with a larger live room with a couple of smaller isolation rooms/booths. I know I will have some questions about that when the time comes

My advice here would be to stop building, right now! Don't do anything else at all, until you have the complete design in place. Trying to design "on the fly" while you also build is a guaranteed recipe for disaster. I'd suggest that you start by buying two books: "Master Handbook of Acoustics" by F. Alton Everest (that's sort of the Bible for acoustics), and "Home Recording Studio: Build it Like the Pros", by Rod Gervais. Read through both of those, so you get a basic understanding of the principles of acoustics, and the principles of designing and building a studio. Then sit down and actually design your studio, in full detail, doing all the calculations that you need to do, and double-checking everything to make sure it will all work, not only acoustically but also safely and practically and legally. Once you have all of that done, then and only then should you carry on building. When you do that, you will likely realize that you need to do some serious modifications to what you already have, if you want to get good isolation. The way it is now is only going to provide moderate isolation, unless you are prepared to spend serious money and go to great complexity for compensate for the decisions you already made.

my neighbours are quite close and I need to avoid any difficulties with them... I have to be able to have a loudish drummer bashing away for hours at a time without them getting annoyed.

So you absolutely do need good isolation then! And what you have so far is not going to get that for you...

(Not very scientific I know but basically I will just get the best sound insulation I can realistically afford and live with it)

That's not a very good plan at all. That's like deciding on what car to buy based on the color of the tyres and the type of radio it has... :) Or deciding on what drum kit to buy based on price alone "and living with it". In which case, you'd end up with this: It would be far, far better to first determine what your isolation needs are (for example, by checking what your legal responsibilities are in your area, so you can avoid being shut down and fined by the cops the first time you play too loud), then look for construction techniques and materials that fit your budget and produce that level of isolation. It's pretty easy to determine how loud you will be in a typical session, compare that to the levels that you are legally prohibited from exceeding in your area, and thus arrive at a simple figure: "I need XX decibels of isolation". Then it is relatively easy to look at the abundant literature on isolation techniques, and laboratory testing, to see which ones provide that level of isolation, then make a decision of how to build based on that. Just guessing and hoping for the best is not going to get you to a usable result. It will get you the acoustic isolation equivalent of the drum kit above. There are only a few ways to build a studio right, and probably a few million ways to build it wrong, so the chances of you hitting on one of the correct ways purely by accident are pretty low!

There is just a metre of space between the outside walls of the studio and the fence to my neighbours gardens.

That's pretty close! You will need a very high level of isolation to avoid that dreaded knock on the door by your friendly neighborhood cops...

As the floor is a big concrete slab and there are double brick walls it seems that the weakest point is always going to be the roof.

Very probably it is ONE of your weak points but not necessarily the ONLY one. Since you will have to build a 3-leaf system to complete the studio, there is the potential for reduced isolation in low frequencies. That's why the general recommendation is to always avoid three-leaf systems in studio construction, since two-leaf is so much better from that point of view. And since you have not yet mentioned your plans for the HVAC system, that too is going to be a major weak point. As is the electrical system.

I will put up 2x 12.5mm plasterboard underneath the beams and then the same again for the ‘room within a room’, hopefully that should be enough as I don’t know what else I can do.

It won't be enough, no, regardless of how much you "hope" about it! :) You did not mention how the roof is built, but it looks to be something light-weight and simple, such as plywood or OBS decking with asphalt shingles, roofing felt, and tin capping. You aren't going to get much more than about 40-something decibels of isolation from that, best case. Assuming typical drum levels of around 115 dB inside, you will have levels of around 75 dB outside, which is probably about a thousand times higher than permitted by your local noise regulations (it's usually about 45 dB in most residential areas these days). So you'd about a thousand times better isolation (a change of 30 dB is indeed a change of one thousand times the intensity) to meet typical legal regulations. So no, "hopefully" isn't going to work here, and your noise levels will likely be both very unpleasant for your neighbors (and your family), as well as being illegal. Fortunately, most police officers are understanding, and won't fine you the first time: they'll just politely ask you to turn it down. But if they have to come back repeatedly to deal with noise complaints, they will shut you down eventually, and fine you. I'd suggest that you need a much better plan than "hopefully" here!

I will put up 2x 12.5mm plasterboard underneath the beams and then the same again for the ‘room within a room’,

Once again, that would create a 3-leaf system, with the associated loss in low frequency isolation. You cannot afford to lose any low frequency isolation, because drums put out a very large proportion of their total acoustic energy in low frequencies. So you should most definitely avoid building your ceiling as a 3-leaf system.

I hope to be able to make decent quality recordings for an acoustic jazz quartet or quintet.

The quality of the recordings depends mostly on the acoustic treatment inside the rooms, and the layout of the rooms themselves. That needs careful design too. The books I mentioned above will guide you through that, and teach you the basics of how rooms should be dimensioned, built, and treated in order to achieve good acoustics. There's a method for ensuring that each room has optimum acoustic response. And the acoustic design within the rooms is totally unrelated to the acoustic design for your isolation needs. Isolation and treatment are two very, very different aspects of acoustics, and are only distantly related. What you need to do to isolate your studio has very little do to with what you need to do to treat it.

I am just preparing to screed the floor ...

Why? It seems that you have a perfectly good concrete slab there, which is about the best possible floor you can get for a studio. Why do you want to do anything on top of that? If you don't like concrete, then your best bet would be to lay laminate flooring on top of a suitable underlay, but that is the FINAL step in building each room, and happens after the rest of the room is completed (walls and ceiling built): the floor at present needs no further treatment.

I have got lots of polystyrene insulation (100mm) which will sit on the concrete slab

Once again: why? Is that for thermal reasons? Polystyrene has no acoustical uses, because it is closed-cell foam, so it is pretty much useless for acoustic treatment or acoustic isolation. Or are you attempting to float your floor? If this is an attempt to float the floor, then you need to read this: viewtopic.php?f=2&t=8173

My concern is that the ‘room within a room’ is going to be HEAVY -

Yes it will be,... massively heavy, in fact. Which is why the inner-leaf walls do NOT normally go on top of a floated floor (unless you need extreme levels of isolation...). The inner-leaf walls are almost always built on the slab itself, then the finish flooring is laid within the walls. Even if you do want to float your floors, you only need to float the part that is within the inner-leaf walls, in most cases. Very, very rarely is it necessary to float the entire room. And you don't heave enough budget left to do that anyway. Properly floating a floor is very expensive, and very hard to do. See the above thread for details.

roof beams (8x2, probably about 20 of them)

From the photos, your roof seems to be entirely complete already! Why do you need to add more beams to that? Is it not structurally sound? Are you planning to add more mass to it (which would be a good idea anyway)? If so, have you done the calculations? Are you certain that 2x8 beams spanning that distance will be able to support the load that will be placed on them, while still meeting the correct deflection criteria?

All this has to sit an inch or so away from the existing walls

Why? How did you determine that an inch gap between your block walls and your framing is sufficient? What resonant frequency are you aiming for here (for the MSMSM assembly), and what amount of mass and air gap do you need to achieve that? Don't forget that you have a 3-leaf system, so you will need a larger than normal air gap, and greater than normal mass on your leaves, in order to keep the resonant frequency down low enough that the third-leaf effect is not an issue.

so I am worried about it compressing the polystyrene

What are the characteristics of the polystyrene ? What is its resilience? What loading can it handle, how much deflection does that cause, and is it approved by the manufacturer? What loading have you calculated? How will you ensure that the load is spread evenly, so that the entire room does not tilt down on one side? What live load are you allowing for, in addition to the dead load? What are the dynamic compressive modulus, sheer modulus, and compressive stiffness of the polystyrene that you have? What transferability will that produce at resonance, and is that sufficient?

and cracking the screed (or chipboard) and ultimately falling down and causing a disaster.

Right. That is indeed one of the many factors that need to be calculated (not guessed) when designing a floated room system. It is very complicated to figure out, and very expensive to do. Are you SURE you want to go down this path?

I am wondering if I need to reinforce the edges in some way

If you are wondering that, then you should not be designing it! Sorry to be so blunt, but this is a big deal. Red flags are waving all over the place here: I see a lot of "hopefully" and "I wonder" and "not sure" and "uncertain" in your post, but I don't say any calculations, and frankly that scares me. I don't see any place where you say that you did the math and figured out that 2x8 white cedar beams laid 400mm OC will safely span 4.3m with a dead load of XX kg/m2 plus a live load of YY kg/m2. I don't see any math where you figured out that the resonant frequency for your floated floor should be ZZ Hz, and you will attain that with a surface density of AAA kg/m2 over a BB cm air gap, with CCC insulation, or with a DDD type spring system spaced EEE mm OC. In short, I don't see any calculations at all, and you are talking about building major structural systems that would kill you, your family, and your neighbors if they collapsed because you got a number wrong. Warning bells are ringing, red flags are waving... This is not a safe situation. You cannot just guess at this stuff. Your studio will weigh thousands of kilograms, way more than enough to crush you like a grape under a dropped brick. You should be even more worried than I am about this, because you will be standing under it, while I am sitting here safely in my own place (which just survived an 8.3 earthquake), thousands of kilometers away...

Does anyone have an idea about the best way to proceed?

YES! The best way for you to proceed right now is to NOT proceed with any building! Sorry too be harsh, blunt, and "in your face", but I'm sort of known for that here, and hopefully that the reason you came to the forum in the first place: to be told the truth. And the plain truth here is that you are getting yourself into very, very dangerous situation, which is probably also illegal. (However, getting sued or being charged criminally is probably the least of your worries, if you are dead from being crushed by a collapsed ceiling or wall...) The truest statement in your entire post is in the first line: "I am feeling seriously out of my depth". Yes, you are. I'd say that the very best thing you can do here is to stop all building activity, and either take the time to learn how to do this correctly yourself (realistically: six months to a year, minimum, of constant study, several hours per day), or get professional help in designing and building your studio. The path you are following right now is doomed to failure. In the very best case, it won't fall down but also wont work as as studio, and you will have constant complaints form your neighbors, despite having spent 70k on it. Worst case: you'll be seriously injured or dead, as something unsafe collapsed on you. I don't mean to be insulting or belittling: I only mean to keep you from making further mistakes, that could be only costly at best, or fatal at worst. Hopefully you'll take this advice in the spirit it is intended: constructive, not destructive. - Stuart -

Hi Stuart, and thank you very much for your lengthy reply. I really do appreciate it, I know you are trying to help me out.

Soundman2020 wrote:

you already have a "room within a room". You already have a two-leaf wall. Adding another leaf to that will create a 3-leaf system, which could potentially REDUCE the amount of isolation you get for low frequencies, unless it is carefully designed to avoid that.

The thing is that this is the way houses are built here in the UK, there really was no option but to build a cavity walls in this case. Because the extension is living space and attached to the house I am pretty sure there is no other allowable way to build external walls to a house other than using cavity walls. It was also important that it could be one day turned back into a normal room - one day I may move and somebody else may want to use it as a granny annex or whatever. A new construction that is only useable as a recording studio would be very bad for me because it would affect the house price (which is my pension - unless I make any money playing music haha)

Soundman2020 wrote:

It seems that you have a perfectly good concrete slab there, which is about the best possible floor you can get for a studio. Why do you want to do anything on top of that? If you don't like concrete, then your best bet would be to lay laminate flooring on top of a suitable underlay, but that is the FINAL step in building each room, and happens after the rest of the room is completed (walls and ceiling built): the floor at present needs no further treatment.

Unfortunately the law says we have to insulate ;-) In theory it would be possible to insulate underneath the main slab instead of on top but due to the intricacies of the raft foundation (designed at great expense by my structural engineer) it was not possible in this case, maybe because the foundations has different thicknesses at different points or because some of the structure is underground, I don’t know. This method of building, with the insulation on top of a slab with 75mm screed on top, is common here in the uk.I am not trying to ‘float the floor’ - the insulation has no springy properties - just trying to comply with the building regulations. If you are interested you can view the building regs here…my particular floor design is on page 25 (similar anyway, I had some alterations because a wall is partially underground). https://www.fdean.gov.uk/media/Assets/P ... L_2014.pdf

Soundman2020 wrote:

From the photos, your roof seems to be entirely complete already! Why do you need to add more beams to that? Is it not structurally sound? Are you planning to add more mass to it (which would be a good idea anyway)? If so, have you done the calculations? Are you certain that 2x8 beams spanning that distance will be able to support the load that will be placed on them, while still meeting the correct deflection criteria?

Yes the roof is built already. The beams you can see in the photos are resting on the brickwork (on wall plates) and support the roof (boarding, insulation and felt layers). I will be plasterboarding over them in a while. A ‘room inside a room’ structure would need a secondary set of beams to hang a 2nd ceiling on which would in turn be supported by new stud walls. 8’x2’ beams (C24 @ 40cm centres) should be fine for the span (max 4.6m) as this is the spec the builder already used for the slightly longer existing roof span and this was calculated by the structural engineer (the plans were passed by the planning authorities and the building control guy has checked that they have been built correctly). I am thinking that this would be a better option than hanging a second suspended ceiling off the existing beams for 2 reasons - firstly that I should get better isolation when the 2nd ceiling is formed from a well separated structure, and secondly that the existing roof has not been designed to support the weight of a 2nd suspended ceiling and I have no idea if it would be strong enough, probably not.

Soundman2020 wrote:

Sorry too be harsh, blunt, and "in your face", but I'm sort of known for that here, and hopefully that the reason you came to the forum in the first place: to be told the truth. And the plain truth here is that you are getting yourself into very, very dangerous situation, which is probably also illegal. (However, getting sued or being charged criminally is probably the least of your worries, if you are dead from being crushed by a collapsed ceiling or wall...)

Please don’t worry too much … I have no intention of doing anything unsafe. Everything I have done is up to spec and has been passed by the building inspector. My concerns are that I have no idea how to support the weight of a ‘room within a room’ whilst keeping to the building regulations. Obviously I realise it is important, hence my investigation. Anyway the building inspector is coming over on monday to check everything is hunky dory, I shall quiz him/her about what level of support I may need for internal walls and then go from there.

Soundman2020 wrote:

I'd suggest that you start by buying two books: "Master Handbook of Acoustics" by F. Alton Everest (that's sort of the Bible for acoustics), and "Home Recording Studio: Build it Like the Pros", by Rod Gervais. Read through both of those, so you get a basic understanding of the principles of acoustics, and the principles of designing and building a studio. Then sit down and actually design your studio, in full detail, doing all the calculations that you need to do, and double-checking everything to make sure it will all work, not only acoustically but also safely and practically and legally. Once you have all of that done, then and only then should you carry on building. When you do that, you will likely realize that you need to do some serious modifications to what you already have, if you want to get good isolation.

Yes I have the Gervais book and have read it, at least the sections that are applicable. The trouble is that none of it is specific to the way that houses are built in the uk so it hasn’t been much help in that respect. In other respects it is fantastic, I have learnt loads. The other book is now on order.

Soundman2020 wrote:

It would be far, far better to first determine what your isolation needs are (for example, by checking what your legal responsibilities are in your area, so you can avoid being shut down and fined by the cops the first time you play too loud), then look for construction techniques and materials that fit your budget and produce that level of isolation.

Yes I will have a good think about this. The limiting factor though is not how much isolation I need or want but how much is achievable for a reasonable budget. The regulations here in the uk are slightly curious - basically you can make as much noise as you like until someone complains about it. I regularly have full band rehearsals in my front room with the windows open, the neighbours like it (!!!) but that is only a couple of times a week - they may feel differently about incessant drumming. So keeping levels to a point that they are happy is not really an exact science, it depends upon their moods! I do need to be a good neighbour though, I really do not want complaints. Of course I need isolation to keep noise out as well but luckily the building is a good way from the nearest road (30m at least) and it is a very quiet little road anyway. The seagulls and neighbours dogs are the noisiest things around, the occasional helicopter. It won’t be a 24/7 type studio with high paying clients in any case, I won’t be doing any playing of drums after 10pm, I mix pretty quietly but I do like to play the piano at 3am.

Soundman2020 wrote:

It's pretty easy to determine how loud you will be in a typical session, compare that to the levels that you are legally prohibited from exceeding in your area, and thus arrive at a simple figure: "I need XX decibels of isolation". Then it is relatively easy to look at the abundant literature on isolation techniques, and laboratory testing, to see which ones provide that level of isolation, then make a decision of how to build based on that.

Me playing the drums loudly is approx 110-115 db. Peaks could be a bit higher,just like other drummers. I can’t find any figures on how much isolation a brick wall with 100mm filled cavity with medium dense blocks on the other side will give me, so my calculation for the walls ended right there. Not to worry I thought, the roof is going to be the weakest point and I can calculate for that… Basically the structure of the roof is not really airtight and it is pretty light weight- just one layer of wood board, 120mm of celotex and 3 layers of felt. There are massive gaps around above the wall plates as well which i will fill up with celotex (again because of the building regs) which will provide pretty much no sound isolation. Because of this I was just discounting this as a leaf and taking the plasterboard layer beneath the beams as the first leaf. I was thinking that 2 layers of 12.5mm pb (with suitable caulking) attached to the existing beams with another fairly decoupled leaf (held up by a new set of 8x2s supported by stud walls) of 2 x 12.5mm pb with a 9’ gap and some fluffy insulation that would give me an stc of around 63 (approximated from Gervais book). Will it be enough? I don’t know but this method does seems to be a common approach here, and I cannot think of any other method that is better. Hopefully there is and I have overlooked something basic?

Soundman2020 wrote:

The path you are following right now is doomed to failure. In the very best case, it won't fall down but also wont work as as studio, and you will have constant complaints form your neighbors, despite having spent 70k on it.

I fear you are a touch on the negative side. Everything I have done has been within the building regulations and has been inspected and passed by the building inspector. There has been no option to use other designs other than the one I have gone with. There is not a singe technique that I have used (or plan to use) that has not been used in successful builds that I have read about here on this forum. It is true that I am very ignorant about building matters (I think I mentioned I am a musician and not a builder) which is why I am very keen to have any of my crazy building ideas ripped apart by experts (Thank you, you are doing a great job ;-). I’ll report back when the building inspector has issued his/her verdict and I will post up some rough designs (once I have learnt how to use sketchup a bit better). cheers, David

" My concern is that the ‘room within a room’ is going to be HEAVY - studs, 2 layers of 12.5mm plasterboard 3m + high, roof beams (8x2, probably about 20 of them) and 2 more layers of plasterboard on the ceiling. All this has to sit an inch or so away from the existing walls (which would be right on the edge of the concrete screed), so I am worried about it compressing the polystyrene (which doesn’t seem that strong) and cracking the screed (or chipboard) and ultimately falling down and causing a disaster." All things considered, I think I would wait on the screed at this point. In the future as you come to a better understanding about what you have and which direction you are going in then, if you find that interior wall assemblies are still in order, build the walls and then install the screed. Stuart has point out very realistic concerns. I suspect the new coupled block and brick you have do have good isolating ability, but that roof has got to match it in some way or it isn't going to get you the ability to contain your noise or stop outside noise...like planes and trains and lawn mowers, etc. And solid core doors with good sealing and thresholds cannot be overlooked. That roof...I dunno...needs some work.

So the building officer came round today and I thought I would report back on what he said …. He was quite happy with everything (very very good news), the whole structure is safe and built properly in accordance with the regulations. We discussed some issues - drainage, fire escapes etc and I quizzed him at length about my screed problem. What he said was that it would fine to build a light stud wall on the screed as long as it was at least 75mm thick and reinforced with chicken wire. I explained that the walls would be heavy and he suggested that thick boarding on top of the screed should spread the load enough for a fairly heavy structure, but I was not that convinced that would be safe for my proposed design. Ultimately we agreed that it was a good idea to cut away the insulation at the points where the walls will go so the screed will fill in those gaps to be directly in contact with the slab. This gives a nice solid base to build the internal frame from - a total of 75mm screed + 100mm extra screed (which is where the polystyrene insulation would have gone) resting on a minimum of 300mm of slab reinforced with lots of steels - in other words at least 475mm of steel reinforced concrete. I should be able to build a block of flats on that! (Which is good as I don’t fancy being squished like a grape). The only trouble is that I have to decide where the walls are going to go in the next week or so before I get the screed delivered. I am going to have to do some fast planning, at least for the basic layout. I can leave the finer details until later but I need to move as fast as possible to get the room weatherproofed before the winter really kicks in. There is still quite a way to go! I will and get a rough plan up as soon as I can as I would love some feedback. I have already thought about the layout quite a bit - I have some particular (and probably unusual ) requirements. Still there are bound to be plenty of things that I haven’t yet considered so I welcome any ideas.

xSpace wrote:

" Stuart has point out very realistic concerns. I suspect the new coupled block and brick you have do have good isolating ability, but that roof has got to match it in some way or it isn't going to get you the ability to contain your noise or stop outside noise...like planes and trains and lawn mowers, etc. That roof...I dunno...needs some work.

Hi Brien and many thanks for your comments. I figure that the preliminary plan for my roof is pretty much in line with other successful builds, like this one from the uk which has a similar looking roof …. viewtopic.php?f=2&t=14814 But I am open to any ideas that anyone may have that would give better results. The design of the inner frame is the aspect I know least about so I am really keen to hear of any ideas that will make things easier better or cheaper.

Well that will be a three leaf assembly...his was.

xSpace wrote:

Well that will be a three leaf assembly...his was.

Yes, if a non-airtight lightweight roof counts a s a leaf, but it seemed to work out ok in that instance. More importantly is there an alternative?

The roof system had plywood on the top it had sheet rock on the bottom so that is an enclosed air space which has been proven to reduce low-frequency isolation so it was a three leaf and it was in a bad way. What you want is a better design. Like you might consider how much mass being placed on the upper side of the rafters would that be a better place to put the mass. Then on your building framing inside you could sheetrock the bottom side of your Rafters but you want a flat area just going to be helpful and then use your interior roof as a treatment you don't put mass on it so that way you have a two leafe and then you use your existing interior ceiling as acoustical treatment.

xSpace wrote:

The roof system had plywood on the top it had sheet rock on the bottom so that is an enclosed air space which has been proven to reduce low-frequency isolation so it was a three leaf and it was in a bad way.

That is a shame.

xSpace wrote:

What you want is a better design. Like you might consider how much mass being placed on the upper side of the rafters would that be a better place to put the mass.

A better design would be good! Unfortunately I can’t see that working. The worst area for isolation is above the wall plates (i.e. below the top leaf) so if I were to put more mass above the rafters (or attached to the existing boarding between the rafters) then the sound will just leak of these gaps there anyway. I couldn’t add any more mass anyway because the rafters are not designed to cope with more weight. Already with a 5m span this is near the maximum for this type of roof design. Before I got this roof built I did investigate other more heavy duty designs but they were impossible due to either cost or due to the extreme problems of access to the site. I really appreciate your thoughts and ideas but I think there is no option than to work with what I have. Maybe I can increase the mass of the inner shell to some significant degree or do something else to compensate for the isolation loss? cheers, David

This is the details of the roof construction ...

Here is the basic plan of the space. It is hard to read the dimensions on the photo but the internal space is 12.55m length and internal width is 466cm on the left end and 394cm on the right end. I didn't make the room non-rectangular for any acoustic reasons, just to maximise the available space. The height is currently around 3.5m to the roof rafters, I am hoping for a finished room height of at least 3m. There is no window on the right anymore and the windows that join on to the house have been bricked up. The double doors there will be bricked up as well at some point. I'll try to get a basic sketchup of a plan up asap Many thanks for taking a look cheers David

A better design would be good! Unfortunately I can’t see that working. The worst area for isolation is above the wall plates (i.e. below the top leaf) so if I were to put more mass above the rafters (or attached to the existing boarding between the rafters) then the sound will just leak of these gaps there anyway

I cannot see the print well enough to define it. But when I said mass, I only meant if you were considering 12mm plywood, I would suggest 15mm...more mass.

xSpace wrote:

I cannot see the print well enough to define it. But when I said mass, I only meant if you were considering 12mm plywood, I would suggest 15mm...more mass.

Thanks Brien, I see what you mean. I think my builders used 18mm OSB for that, I would have to double check to be sure.

Hi, I am having a think about how to layout my studio and have come up with this rough plan of how to divide the space in my room up. This is the ’room inside a room’ design only - wood frame and plasterboard that sits inside the outside shell that I already have. I have juggled with different layouts but this seems best so far. It is not in any way exact or finished, I am just considering where to place the main walls which I need to decide on as soon as possible, everything else can be decided more exactly later on. The rough principles which I thought were important are … - The live room and Drum room have no doors or windows to the outside (thus maximising isolation for the rooms that need it most) - entrance has to be big enough to get my large grand piano to the live room - good sight lines between drum room, live room and iso booth are essential. Not really necessary to the control room. - live room must be large enough for full rehearsals (piano bass drums and 2 horns at a minimum) - Control has the window, which is required as a fire escape (yes it has to open) - got to have some natural light in the live room (hence a ‘glass’ door from the control room), because I spend a lot of time practicing the piano and composing and hate rooms with no natural light. - the control room is pretty much symmetrical Air conditioning - will think about this properly later on, but for a start …. - probably 2 mini split systems, for the control room and live room - 3 fresh air systems (including silencers) for control, live and drum rooms electrical - will think about this properly later on, but for a start … get an electrician to take a supply from my existing consumer unit (30A) and then have a secondary consumer unit in the studio with separate circuits for audio gear and air conditioning and lights. acoustic treatment … yes, lots of rock wool employed in various ways, details later. internal doors will be of the heavy do it yourself type with heavy duty closers. If anyone has any thoughts on this then I would love to hear them. Thanks in anticipation. Cheers David

There are several issues with that layout that you should probably re-think. Firstly, your control room is facing the wrong way: it gets narrower towards the back, when it should either get wider or just stay the same width. So you should flip the internal orientation by 180°. Yes, that does leave the large window behind you, in the worst possible location, but there are ways of dealing with that, and it's the "lesser of two evils". Second, the dimensions are pretty bad: there will be large modal issues. There are mathematical equations and models for determining if your room ratio is good or not. Yours isn't. The BBC uses a set of three pass/fail tests to determine if a room is suitable as a control room or other critical listening room: a fail in any one of those is cause for rejecting a room. Your room fails two of the tests. I would suggest that you adjust the dimensions to get a good ratio, or at least to get away from the bad one where you are right now. Flipping the orientation of the CR would also give you the potential for good sight lines into the other rooms, with careful planning. The iso booth would have to be re-located for that, but there is space to do that. Next, you mentioned (and show) the grand piano in the LR, but there's no way to get it in or out! You did mention that you need to leave an access path for that, but there isn't one. The only door into the entire facility is that small one at the far end, in the flanneled room that is only 1.5m wide. There's no way to get a grand piano through there, not even on its side. Speaking of that "unlabeled room" the purpose is not clear at all. IS that going to be used for storage? Or is it just an entrance hall, where you can hang your coat and hat and leave your umbrella? There doesn't seem to be any other purpose for that room, so it looks like wasted space to me. Next, most of your doors are poorly laid out: they clash with each other! They need to be repositioned so that each door can swing through its full range without hitting any other door that might be partly open. Speaking of doors, you are only showing ONE door in each location, when there should be two. Is that just shorthand for the initial design? Were you planning to add the second door of each pair later, in the more detailed design? Speaking of shorthand, you seem to be using the same shorthand for the walls: you show them all fully coupled, with no isolation at all between rooms. I'm assuming that you plan to correct that at a later stage, and show the complete decoupled 2-leaf systems? The same applies to the windows: you seem to be showing just a single pane of glass in each window, thus leaving no isolation between rooms. Once again, I assume you'll correct that when you start fleshing out the details of the isolation system? You also mention that the large window in the CR "must" open! :shock: :ahh: Umm... if that's the case, then you wasted a huge amount of money on trying to isolate the rest of the studio. Normal operable windows cannot be used in studios, for the simple reason that they offer somewhere between "zero" and "zilch" for usable isolation. I would suggest replacing that window with a pair of back-to-back acoustically rated sliding glass doors, such as the ones you see in many of John's designs. One door goes in the outer leaf, the other goes in the inner leaf, just like for all the other doors and windows. That's still not a perfect solution, but it will get you decent isolation. Of course, they do have to be acoustically rated sliding glass doors, not just the typical sliding patio doors you buy in hardware store, so that will impact your budget, but it's the best solution. The other option (and probably the best option) would be to leave keep that window fixed (not operable) (as a normal pair of back-to-back panes separated by a large air gap) and just put in a door to provide the emergency exit. Probably much cheaper, too. Finally, there's the issue of acoustics: both drums and grand pianos need a lot of "air" around them to sound good: just plenty of empty space. Your current design does not provide that. There is wasted space in the unlabeled room where the entrance is, and wasted space in the iso booth. There are better ways of laying out the rooms overall, making better use of space. You also mentioned that you'll leave the details of HVAC until later, but that would be a mistake: you need to account for the ducts and silencer boxes now, in the initial design. They are large, and take up a surprising amount of space, so they have to be factored in from the beginning. Trying to retrofit them later, after you have already settled on room sizes, layouts, door and window locations, etc. is not going to work out well. You'll have to move walls, doors, windows, ceilings and everything else around to fit those in, so you might as well do that now, instead of later. OK, now for comments on some of the things you said:

This is the ’room inside a room’ design only - wood frame and plasterboard that sits inside the outside shell that I already have.

You seem to be missing the point of what "room in a room" really means. Since you have a total of five rooms, it would be more correct to refer to your studio as "five rooms inside a room". The single "a room" is what you have already: the outer shell. Now you need to have five separate, independent, individual rooms that all sit within the outer shell. Each room is a single leaf, all on its own, that does not touch any other room in any way, and neither does it touch the outer leaf. Each room consists of a stud frame with drywall on only ONE side of it. That fame includes the walls and the ceiling. The entire room is a "stand-alone" structure: it supports itself structurally, and does not have any mechanical connections to any other room. Your drawing is not showing that, but since proper "room in a room" construction takes up a lot of space, you really should start showing that now, in order to ensure that everything fits, and your final dimensions are reasonable.

I am just considering where to place the main walls which I need to decide on as soon as possible, everything else can be decided more exactly later on.

This is the other comment that makes me think you are missing the point here. With "room in a room" construction, there are no "main walls"!!! There are only rooms. You already have the only "main walls" that you need, which is your outer leaf. Now you only need to build each of the rooms separately, as its own set of single-leaf walls plus its single-leaf ceiling.

- The live room and Drum room have no doors or windows to the outside (thus maximising isolation for the rooms that need it most)

I wouldn't worry about that too much. If you design the doors / windows properly, you can get decent isolation to the outside world. Your weak point is not going to be exterior doors: it is the existing roof. If there's nothing more you can do to improve the isolation of the roof, then there's no need to worry about a bit of extra leakage through the doors / windows. That's just a drop in the ocean, compared to the leakage through the roof. So you could certainly change the design to have an external door into the live room, which would greatly simplify getting large items in and out (such as the grand piano).

- good sight lines between drum room, live room and iso booth are essential. Not really necessary to the control room.

I'm curious about why you don't think sight lines to the control room are important. In my experience, sessions go an awful lot smoother when the musicians and the engineer can all see each other clearly. Talk-back and intercoms and CCTV are useful tools, yes, but nothing beats direct visual contact through glass. Since you have the opportunity to get good sight lines, it seems to me that it would be a good idea to do so.

- live room must be large enough for full rehearsals (piano bass drums and 2 horns at a minimum)

Right now, it isn't. I assume you mean that you'd like to track all four of those at once, which means that you'd need some pretty hefty gobos to try to reduce bleed between them by at least a few dB, but there's not enough space even for what you mention, without considering gobos.

- Control has the window, which is required as a fire escape (yes it has to open)

I'm betting that your building codes does not specify that you HAVE to have a window there: just that there must be an escape path. A door is a much better escape path than a window anyway, and is cheaper to implement, has less impact on room isolation and room acoustics. If that were my studio, I'd go with a door for access, plus a window for natural light. Or maybe two windows. Or sliding glass doors (acoutic ones)- In fact, if that were my studio, I'd have the LR at that end of the building, for easy load-in / load-out, especially for that grand piano.

- got to have some natural light in the live room (hence a ‘glass’ door from the control room), because I spend a lot of time practicing the piano and composing and hate rooms with no natural light.

Even more reasons to have the LR at the end of the building where you can have a large window! Moving the CR to a different location would also fix the problematic acoustics of having glass on the rear wall...

- probably 2 mini split systems, for the control room and live room

And what about the drum booth and the iso booth? Those are much smaller spaces, and will get uncomfortably stuffy and hot much faster than the bigger rooms. The poor drummer is going to suffer pretty badly in there with good HVAC! Ditto anyone playing in the iso booth... And there's still the mystery of the unlabelled room: if that will also be used for people doing things, then that needs HVAC too. For a facility that size, it would be cheaper and easier to just put in single AHU and a zoned system with a simple controller.

- 3 fresh air systems (including silencers) for control, live and drum rooms

You only need one system, which splits out into all five rooms, then all the returns come back together again. Motorized dampers, run by the system controller, take care of moving the right amount of air into and out of each room.

electrical - will think about this properly later on,

Don't leave that too late! Once again there are some important implications for isolation, with electrical work. For example, there can only be one single penetration into each room, to bring the power feed in, then all of the internal wiring is done using surface-mount stuff. If you leave it up to an electrician, he'd be chopping holes in your walls for each and every switch, outlet and lighting fitting! :shock: But of course in a studio that is impossible, as it would totally destroy the isolation. Some everything is surface mount inside each room, and the one single penetration is also decoupled and isolated, acoustically.

get an electrician to take a supply from my existing consumer unit (30A) and then have a secondary consumer unit in the studio with separate circuits for audio gear and air conditioning and lights.

And don't forget to tell him that you need star grounding, not the typical loop grounding.

yes, lots of rock wool employed in various ways,

well, that's a start, yes, but your rooms are going to need a lot more than that to get decent acoustics! :)

internal doors will be of the heavy do it yourself type with heavy duty closers.

Not sure what you mean by "do it yourself" in this context. Are you talking about the typical pre-hung DIY doors that you buy in building supply stores, ready to just slip into the rough opening? Or are you talking about building them yourself on-site?

If anyone has any thoughts on this then I would love to hear them. Thanks in anticipation.

There's plenty more that can be improved, but I think that covers most of the bigger issues so far. - Stuart -

Hi Stuart, thank you so much for your long and helpful answer.

Soundman2020 wrote:

Firstly, your control room is facing the wrong way: it gets narrower towards the back, when it should either get wider or just stay the same width. So you should flip the internal orientation by 180°.

Yes I see what you mean, but it is only by about 30cm so I could easily build the stud walls to make the room exactly rectangular or even slightly fanning out the other way if that is important. Or I could just use the extra space for additional bass trapping. Or I could rotate the control room by 90 degrees.

Soundman2020 wrote:

There are mathematical equations and models for determining if your room ratio is good or not. Yours isn't. The BBC uses a set of three pass/fail tests to determine if a room is suitable as a control room or other critical listening room:

I was worried about the room being a bit square, obviously it is not ideal. Maybe I can adjust the dimensions a bit for a better ratio. I will do some experimenting with that.

Soundman2020 wrote:

Next, you mentioned (and show) the grand piano in the LR, but there's no way to get it in or out!

I am moderately sure that the piano will fit in and have gone as far as seeking advice from piano movers and even building a 3d model. My piano is just over 2m (although I need to plan for a 2.3m piano just in case I ever get a bigger one). Piano movers can tilt the piano onto the key end, but it is tight and I am a bit worried about it. It would be much better to have an alternative.

Soundman2020 wrote:

Speaking of that "unlabeled room" the purpose is not clear at all. IS that going to be used for storage? Or is it just an entrance hall, where you can hang your coat and hat and leave your umbrella? There doesn't seem to be any other purpose for that room, so it looks like wasted space to me.

I was thinking a store for extra instruments (I am always going to a gig or coming back from one), hats and coats, a good place to have a large isolated box for a guitar amp, space for fresh air fans and silencers, electrical consumer box etc.

Soundman2020 wrote:

You also mention that the large window in the CR "must" open!   Umm... if that's the case, then you wasted a huge amount of money on trying to isolate the rest of the studio. Normal operable windows cannot be used in studios, for the simple reason that they offer somewhere between "zero" and "zilch" for usable isolation. I would suggest replacing that window with a pair of back-to-back acoustically rated sliding glass doors, such as the ones you see in many of John's designs.

Yep, I get that. The trouble is money and the legal requirements. I was planning on 2 opening double glazed windows - one in the outside shell (buildings control at this stage have to see this to pass the building) and another on the inside shell. The advantage of these is that I have just taken them out of my house so they are free! I could at a later stage put in 2 sets of acoustically rated sliding doors (when I get richer) but I suppose I am hoping to not need that much isolation for the control room. It is the live room and the drum room that require more isolation and if I can achieve that there then the specs for the control room can be less. Talking of which does anybody know where I can source ‘acoustically rated’ sliding doors in the uk? Any idea of price? I am virtually sure even before checking that they will be outside my budget but I would like to investigate.

Soundman2020 wrote:

Finally, there's the issue of acoustics: both drums and grand pianos need a lot of "air" around them to sound good: just plenty of empty space. Your current design does not provide that. There is wasted space in the unlabeled room where the entrance is, and wasted space in the iso booth. There are better ways of laying out the rooms overall, making better use of space.

Yes the more space the better. I don’t want to waste any because I haven’t got all that much to start with !!!

Soundman2020 wrote:

I'm betting that your building codes does not specify that you HAVE to have a window there: just that there must be an escape path. A door is a much better escape path than a window anyway, and is cheaper to implement, has less impact on room isolation and room acoustics. If that were my studio, I'd go with a door for access, plus a window for natural light. Or maybe two windows. Or sliding glass doors (acoutic ones)- In fact, if that were my studio, I'd have the LR at that end of the building, for easy load-in / load-out, especially for that grand piano.

I am sure you are right. I can see the sense of what you are saying here. The piano could never get in that way though (on the left side) due to access problems (access to the back garden is via a 80cm wide passage) but I can see the advantage of a having a door as the fire escape, then properly constructed windows would give much better isolation.

Soundman2020 wrote:

And don't forget to tell him that you need star grounding, not the typical loop grounding.

I am well out of my comfort zone here. I will have to ask an electrician about this I think. It has to be certified for the buildings control so I don’t know what choices I have here.

Soundman2020 wrote:

Are you talking about the typical pre-hung DIY doors that you buy in building supply stores, ready to just slip into the rough opening? Or are you talking about building them yourself on-site?

I was thinking of buying cheap old used solid wood doors and then beefing them up with mdf or ply and some heavy duty hinges and heavy duty door closers. Gaskets seem to be problematic, haven’t investigated too deeply yet.

Soundman2020 wrote:

You only need one system, which splits out into all five rooms, then all the returns come back together again. Motorized dampers, run by the system controller, take care of moving the right amount of air into and out of each room.

I can’t imagine how that would work, ‘motorised dampers’ and a ’system controller’ sounds prohibitively expensive. I was imagining simple fans and ducting with a couple of silencers for each room. re HVAC for drum room, my thinking is that in the uk probably for 70% of the time pumping a lot of fresh air through will probably cool the room down enough, for the remaining time a portable air conditioner could be used but it would probably need to be turned off when the tape was actually rolling. At this stage I am not sure how much recording I will be doing, if it turns out to be a real lot and the drummers are complaining I can always add an extra mini split later, I can’t see that being too problematic even if a few sheets of plasterboard have to come down.

Soundman2020 wrote:

For a facility that size, it would be cheaper and easier to just put in single AHU and a zoned system with a simple controller.

Would it? How much as a guesstimate would that be? I would suspect that it would be in the £ many thousands. I am figuring 2 mini splits are around £600 each, I don’t know if I can install them myself but I am hoping so. For the fresh air system I am guessing the fans are about £100 each (x3, 1 for each of the 3 main rooms), basic ducting is fairly cheap and home built silencers are as well. If I could get variable rate fans I could even control the rooms independently, don’t know how possible that it. I can see it is important to know where the ins and outs are and where the ducts are running before I build the frame though, needs more thought. So all in all there are many things for me to think about here…thank you so much Stuart for forcing me to do so. I will be back with some modified designs as soon as I can. Cheers David

I was worried about the room being a bit square, obviously it is not ideal. Maybe I can adjust the dimensions a bit for a better ratio. I will do some experimenting with that.

Try these two room mode calculators to help you: http://www.bobgolds.com/Mode/RoomModes.htm http://amroc.andymel.eu/ Both of those are very good, and will help you to decide how best to build your room. As long as you are inside teh Bolt area, and pass all three BBC tests, then you should be good.

My piano is just over 2m (although I need to plan for a 2.3m piano just in case I ever get a bigger one). Piano movers can tilt the piano onto the key end, but it is tight and I am a bit worried about it. It would be much better to have an alternative.

Yeah, that's my thoughts exactly. That's a LOT of money to be heaving around tight corners! I'd really, seriously consider a much simpler access path. Not only for your piano, but for anything else that needs to be loaded in or out. Musicians seem to dislike having to lug their instruments around anyway, and forcing them to navigate a tight labyrinth might not endear you to them!

I was thinking a store for extra instruments (I am always going to a gig or coming back from one), hats and coats, a good place to have a large isolated box for a guitar amp, space for fresh air fans and silencers, electrical consumer box etc.

For a store room, I'd put it some place where you can use pretty much all of it for actual storage. With three doors opening into it, there's precious little space where you could store anything much bigger than a box of matches! :) I'd suggest modifying the design so that you have a direct path into the live room, and putting the store room at some internal location that doesn't interfere with the rest of the rooms.

I was planning on 2 opening double glazed windows

Double glazing is not suitable for studios: The glass is thin, and the air gap is very small. Thus, the resonant frequency is rather high, so the do not isolate well for typical music frequencies. Double glazing is great for what it is designed for: typical street noise. It does wonders for people talking, car noises, wind, and suchlike, but is pretty useless for things like drums, bass, the low end of your piano and other keyboards, the low end of the electric guitar, and anything else that puts out a lot of energy in the bottom few octaves of the musical scale. It would be an mistake to use normal house double-glazed units in a studio, if you want good isolation. Studios are normally glazed with laminated glass, two leaves: one in the outer leaf, one in the inner-leaf. If you wanted the best of both worlds (exit doors, and natural light), and don't want to get into the expense of sliding glass doors, you could just build a pair of back-to-back wooden doors with large glass panes in them.

one in the outside shell (buildings control at this stage have to see this to pass the building) and another on the inside shell.

I did that for a church that hired me to fix their isolation problems a couple of years ago. They had single pane windows on each side of the stage, which I replaced with a pair of back to back windows, one opening out, the other opening in. It worked wonders, and they didn't have any problem getting it approved. And yes, those are operable windows, and escape paths... but it's a church, not a studio! It greatly reduced their sound leakage, enough to meet legal needs, but didn't make it entirely inaudible, because the windows are operable. At the other end of the sanctuary, I replaced a fixed single-pane window with a fixed two pane window (similar laminated glass, similar air gap), and that one is far more effective. It's pretty much dead quite outside that one.

Yes the more space the better. I don’t want to waste any because I haven’t got all that much to start with !!!

I think there are better ways of laying out your studio, that make better use of space.... :)

The piano could never get in that way though (on the left side) due to access problems (access to the back garden is via a 80cm wide passage).

Ahh! OK, i was assuming that was the side that faced the street. I didn't realize that it's the other way around. In that case, I'd move the LR to the right end, and have a door right out there, to the front, for easy load-in / load-out. You could put glass in that one too, to get natural light into the LR, if you wanted to.

I will have to ask an electrician about this I think. It has to be certified for the buildings control so I don’t know what choices I have here.

Star grounding should not be a problem: it actually makes it safer, electrically, since there is a shorter and more direct grounding (earthing) path to each outlet. The basic concept is that the ground conductors from each and every outlet all run back to a single common central point, which has one single conductor from there to your main building ground. It helps reduce the possibility of ground loops (different voltages at different points in the grounding circuitry, which causes current to flow in your grounding, potentially causing "mains hum" issues in your gear).

I was thinking of buying cheap old used solid wood doors and then beefing them up with mdf or ply and some heavy duty hinges and heavy duty door closers

That would work. Many people here on the forum have done exactly that, and it is an excellent (and relatively inexpensive) option. But you still need a pair of doors, back-to-back, at each location where you are showing s single door at present. One door in the outer leaf, and one in the inner leaf, for each and every room. That is critical for good isolation.

Gaskets seem to be problematic, haven’t investigated too deeply yet.

Take a look at the Zero International website. They have everything you need, ready-made. You need at least two seals on every door, that run around the complete perimeter: top, both sides, and the bottom (threshold seal) the drop-down ones are great for the bottom. Each seal most be an unbroken path around the entire door edge. No gaps.

I can’t imagine how that would work, ‘motorised dampers’ and a ’system controller’ sounds prohibitively expensive

Not really. These are motorized dampers: And this is a simple system controller conceptual diagram: And a slightly larger one, more like what you'd need: Typical price: http://www.amazon.com/ECOJAY-SmartZone- ... controller Not complicated at all. And not expensive. You need dampers anyway, either manual or motorized: if not, how else would you control the flow rate for different situations? It's a very different need for having just you sitting in the LR writing music late at night in winter, versus having half a dozen musicians in there frantically playing a complicated piece in mid-summer on a hot day! With no controller and damper, you'd be screwed. No way to handle those two extremes. The system controller and motorized damper do it all for you, automatically. Of course, if you want to do it manually, running around to each damper and adjusting it yourself, then checking the temperature and humidity every few minutes to see if you need to go change them again, then you can do that, but it seems like a lot of effort, complication, and inefficiency just to save a few bucks on a couple of electric dampers and a controller... :)

HVAC for drum room, my thinking is that in the uk probably for 70% of the time pumping a lot of fresh air through will probably cool the room down enough,

... and simultaneously pump in a huge amount of humidity, thus changing the tuning of the drums!!! :!: :shock: As long as you don't mind re-tuning your drum kit every few minutes during every session, that's fine... :) Most acoustical musical instruments are made from wood or other natural materials. All of them change tuning as they expand and contract from changes in temperature, and the ones made with natural materials also change tuning as humidity changes. That's the main purpose of a properly design HVAC system in a studio: it controls the temperature and the humidity in the rooms, keeping them constant, and thus keeping the instruments tuned. HVAC is not just there to keep the musicians comfortable: it is there to keep the instruments comfortable. If you don't have controlled conditions, then you'll have wild swings in temperature and humidity, and thus swings in instrument tuning, tone, and timbre. Even if the tuning doesn't change, the tone still can. Ever noticed that professional musicians bring their instruments into the room and open the cases a while before the performance starts, then tune them several minutes later? There's a reason for that: it gives the instrument time to adapt to the ambient conditions before tuning it, so it stays tuned longer...

for the remaining time a portable air conditioner could be used

How would you use a portable A/C unit in the drum room? You'd need to cut a huge hole on the outside wall to run the exhaust hose through... It seems that you are not thinking this through very well...

I can’t see that being too problematic even if a few sheets of plasterboard have to come down.

I'm not sure I'd agree with you on either of those points! :) (Based on a few years of designing studios for various places around the world... and a few more years of experiencing musicians playing in numerous different environments...) But don't feel alone here: HVAC is usually the very last thing that most home studio builders think about, often until it is way too late. In your case, you are starting to think about it very early on, which is good. You still have time to learn about it in detail, and incorporate it properly into your place, thus avoiding the major issues that others have run into, when they eventually realized just how complex the whole HVAC thing is, and how extremely necessary it is, even for a small studio.

I am figuring 2 mini splits are around £600 each,

... but you need four of them, not two. so there's £2,400 right there. The one for the LR will have to be bigger, and the ones for the drum booth and iso booth will be smaller, but overall I'd guess that around £2,500 would be roughly correct for 4 x mini-split systems. That's roughly the same as what an AHU with the same total capacity would cost... Here's a catalogue and price list I found for you: http://brochures.climatecenter.co.uk/PD ... LM0007.pdf You might find that interesting reading!

I don’t know if I can install them myself but I am hoping so.

No, you can't. There are high pressure coolant lines that need to be installed correctly, and the system needs to be charged and bled correctly with the right coolant gases, then inspected for leaks and checked for correct operation. It's not something you can do, unless you have been trained to do it. Installation costs are high, and they are per unit. So if you have 4 mini-splits, you need to pay for 4 installations, whereas if you have as single AHU, then you only pay for one installation... :)

For the fresh air system I am guessing the fans are about £100 each (x3, 1 for each of the 3 main rooms),

How would you know what type of fan to buy, when you have not done the calculations yet? You first need to find out how many room changes per hour you need for each room, based on occupancy, then you need to figure out the flow rate from that, based on room volume, and also calculate the flow velocity that you will need, which then allows you to calculate the correct duct sizes that can handle that volume at that velocity, then you can figure out the static pressure that your ducts and rooms will impose on the fan (how much resistance the fan "feels" as it tries to move air through the entire system), then you can look for fans that can move the correct volume of air at the correct speed into the correct size of duct when faced with the correct static pressure. Until you know that, you can't quote fans, because you don't know which ones to quote! There's a long way to go until you can find out the price of fans...

basic ducting is fairly cheap

Yes, but the duct liner that you MUST put inside it, is not so cheap. Quote one inch duct liner in your area. It comes in sheets of rolls, and you need enough to completely line the interior of all your ducts and silencer boxes...

and home built silencers are as well

You'd be surprised! A correctly sized silencer box for your live room is not going to be small... You'll need quite a bit of thick plywood to make it.

If I could get variable rate fans I could even control the rooms independently, don’t know how possible that it.

do you really want to be sitting in front of your registers, checking the air flow velocity and speed regularly, then adjusting your fan speeds, to keep the air flowing at the correct rate for the current conditions? then change that several times per hour as the outside weather changes, heats up, cools down, and also as people come in and leave each room? You'd spend more time adjusting fan speeds, than you would mixing!

I can see it is important to know where the ins and outs are and where the ducts are running before I build the frame though, needs more thought.

Yes, it needs a lot more thought. When I'm designing a studio, I normally spend about as much time on the HVAC system as I do on the entire rest of the design. It's a slow complicated process. The reason it takes so long is because changing one thing can cause a whole series of other changes, in a domino effect, so you are constantly going round in a loop, checking what consequences there are from what you just modified, then dealing with those, then checking the consequences of that... HVAC is a BIG part of studio design, and it takes a long time to get it right. Getting it wrong is not an option: if you don't figure out the correct specs for the fan, then either it will move too much air too fast, overspeed and burn out, while also causing air noise in your registers and overloading the AHU with too much humidity or heat, or it will not be able to move enough air, so it will be overloaded with too much "resistance", and end up burning out. If you figure the wrong latent heat or sensible heat, and thus dimension your mini-splits (or AHU) wrong for each room, then either they will be too big for the job, so they will only run for very short periods, causing wild swings in temperature and humidity, or they will be too small for the job, and thus run constantly, non-stop, but still be unable to cool enough or dehumidify enough. If you get the duct sizes wrong in your calculations, then you'll have a lot of noise from turbulent airflow getting into your mic while recording. If you design the silencers wrong (incorrect impedance mismatch, too few baffles, wrong cross-section, ...) then they won't block sound and you won't have any isolation... Etc. Getting any of the parameters wrong can potentially cause problems down the line...

So all in all there are many things for me to think about here…

Yep! welcome to the wonderful world of studio design! :) It is always entertaining, and there's always something to keep you busy, and get you thinking about something else... There's never a dull moment when you embark on the endevour of designing a studio. :)

thank you so much Stuart for forcing me to do so.

That's what we seem to be good at, around here! Some people take it the wrong way, and think we are just nit-picking, or trying to belittle their efforts, or insult them.. but in reality, we are only trying to help them see the issues. This "in your face" type of approach seems to work well, as it really gets people's attention, and gets them thinking. Fortunately, you seem to be one of the guys who "gets it", and sees that we are not bashing your design or build, and our intention is only to do what you probably wanted when you came here: get you focused on the right track to make your studio the best it can be, at the lowest cost. See my signature, below... :) - Stuart -

Thanks for the great advice Stuart. I am really learning a lot … I have tried to redesign to minimise some of the many problems… (plans are a roughly drawn, just trying to get the basics down before I refine) Control room - - smaller, now 3.42m x 4.1m x 3m - conforms to Septmeyer ratio (1:1.14:1.39) pretty closely. Exact dimensions not fixed yet - the max ceiling height I could have (assuming 8” beams and 2x12.5mm pb) is around 3.17m but this could be lowered to 3m or below if it is worth it to achieve a better ratio. - double set of doors to the outside and non-opening windows to the outside, this preserves fire escape but will be a right hassle to build due to building regulations, but it is possible. - double set of doors to live room and windows. - changed orientation by 90 degrees which gives a more pleasing shape. Windows on the side walls are probably not ideal but they are quite far back at least, behind the main mixing position. I could have some serious curtains to cut down reflections for some occasions and make the windows not too big. At least they could be symmetrical. LIVE ROOM- - maximised the space by getting rid of the isolation room. Hopefully I can live without it. Size is now 6m x 3.9m. Height up to 3.17m. These dimensions seem to be ok on the mode tester. (could adjust slightly if required) DRUM ROOM - - maximised space by getting rid of corridor. - dimensions seem to pass the mode tester 2.5m x 3.75m height 3.17m - nice easy in for the piano with double set of doors to the outside. There is some space in the door lobby areas for some silencers. I am guessing there are still some big problems? Many thanks for taking a look cheers David

Just wondering how the design and construction is going? - Stuart -

Hi Stuart and anyone else reading. I have been getting on slowly reinforcing the floor, putting down thermal insulation, dpm and floor screed. The floor is now pretty much finished (photos to follow soon). Things are going a bit slowly now because my builders have more or less finished and most of the stuff left I will have to do by myself. Also I have been reading up quite a bit on various related topics. I have been thinking about the HVAC. I would love to have a fully controllable system (like Stuart was describing) but I think realistically that will be out of my budget. I will get a few quotes in anyway but my entire budget for the complete air system would be at max around £3000 to £3500 . So I am planning a plan B for when I can’t afford plan A! One of the things I am very confused about is the amount of fresh air that is required. I saw on another thread that it should be 4x the volume of the room per hour but this seems to be at odds with other info I have seen. My live room is about 72m3 (and designed to fit 4 people) which means about say 300m3 an hour (84 l/s) based on a 4x room size calculation. Newell on the other hand says “A room with 4 persons would therefore suffice with an air change of around 150m3 per hour , yet building regulations may require 10 times this figure. This can be enormously wasteful, especially if the ventilation system is of the constant loss variety…” “10 litres per second per person is absolutely adequate for ventilation systems in recording studios” (Gervais says 7.5l/s or 25 cubic ft a minute per person). So 40l/s by Newell’s calc, and 30 l/s by Gervais’s. —— I was thinking about getting a ‘TD250/100 silent in line fan’ which is rated at 240m3/hr so that should be more than enough for the 4 person live room and the 3 person control room and way overkill for a single person drum room. Is this the right kind of fan to be looking at? https://www.tlc-direct.co.uk/Products/S ... GwodQKAFew Also I am confused about the silencers. The design seems to be pretty simple but duct liner seems to be hard to get hold of in the uk. I looks like it will cost around £300 just for duct liner for 6 silencers!!! I notice that in the Everest ‘Master Handbook of Acoustics (6ed)’ it mentions using 2’ glass fibre board in the plenum silencer (is that like sheets of acoustic rock wool or something different?). I guess that would have to be well covered to stop fibres being blown around but it would be much much cheaper. Is it realistic to contemplate this as an idea? Re Silencer design - I was thinking of a box around 120cm x 60 cm x 30cm, like the design seen in many threads here. One for the fresh air in and one for the fan powered stale air out, a pair for each of my 3 rooms. And the ventilation hoses - how long should they be? I was thinking around 5m would be about right, that way I could use a hose like this … https://www.tlc-direct.co.uk/Products/FDAD6.html … and cut it in half - one piece for the air in and half for the fan-driven air out (between the silencers and the room). Is there a maximum and minimum length or any advantage for using short or long lengths? Many thanks for any advice Cheers David

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