Hi there Carkus, and Welcome!
identified a good site roughly 30 metres away from the main house to build the recording studio. My closest neighbours (other than my in-laws) are about 80 meters away from the proposed site. The site is on a lower section than the house, and is partially separated by large pine trees.
It sounds like you have an excellent location, with good separation from the neighbours. The trees won't do much to increase isolation, but the distance is good. and with a "ground-up" greenfield approach, that just makes it a whole lot easier to do it right.
8 x 5 meters and built on a concrete slab
Can you go bigger than that? A full 3-room studio with bathroom in 40m2 can be done, but it's a tight fit. I'm doing a design for a similar place in Scotland right now, and at 60m2 it just fits in nicely. That one includes a lobby area and kitchenette too, but even accounting for that, 40m2 is rather tight.
I would mainly be recording Drums and Guitar, however there would also be Bass and Vocals and could possibly reach levels of 110 dB if I was recording things simultaneously or having a band practice.
If you are recording drums, then you have at least 115 dB right there. Drums played loud can easily hit 115dbC, and more...
I would like to reduce the sound by at least 50dB standing directly outside the studio,
That is a reasonable goal, and achievable. Assuming 115 inside, you'd be down to around 65 outside (1 m from the wall), and since you lose between 3 and 6 dB for each distance doubling, you'd be down to no more than 50 (and probably closer to 40) at a distance of 30 m. That's about as good as you can hope to get it on a small budget, and is entirely reasonable.
Design wise, I really like the layout of this studio below that kendale sketched up in this thread a few years back
That was just a design concept, and it was third in line of two much better ones that the OP rejected for various reasons. The problems I see there are:
1) Access. The only way to get from the CR to the LR is by going outside... in the rain and the cold and the dark, dragging mics, instruments and gear through the mud, and the sudden changes in temperature and humidity...
Either that, or drag it through the iso booth, but to do that you'd have to move the mic, amp, gear, music stand, and whatever else you have set up in the booth ....
You DEFINITELY want a design where you have direct access from the CR to the LR.
2) Bathroom in the LR? Ummm... NO! Don't do that. Do you really want the noise and smells from the bathroom permeating the live room? 'Nuf said... (not to mention the changes in humidity in the LR each time the door is opened or closed...) Yes you need a bathroom, but no it does not ho inside the isolation shell: Put it close to the front door.
3) You are trashing your isolation by directly joining your inner and outer leaves where the wall between the isolation booth and the live room meets the bathroom wall. That needs fixing.
4) Both the LR and the iso booth are small. Not much room in there to set up a full band, with drums, bass, electric, acoustic guitar, keyboards and vocals. Try it: download some gear from the SketchUp library, and try to fit it all in...
Budget is 15-20k NZD.
On the low side, for sure! 40m2 on $20k works out to $500 per square meter. I'm not sure what construction costs are like in NZ, but that does seem on the low side when compared to other places. Especially when you consider the cost for plumbing, electrical, HVAC, permits, inspections, structural engineer, architect, pouring the slab, etc. I'd re-think your budget. A really good way to find out how much this is really going to cost, is to call up a couple of local building contractors and ask them for their rate for building a 40 m2 "granny flat" in your back yard. Take whatever number they give you, add about 20%, and you'll have a good estimate of what it will cost, realistically, to build your studio. Of course, if you are doing most of the labour yourself or using free "buddy labour", then you can chop maybe 30% or so off the total, but even then 20k is on the low side.
Interior leaf aiming to use 2 layers of 13mm Gib plasterboard
Don't use 13mm: it's to thin and too flexible for good isolation. Use only 16mm, and make sure it is the "fire rated" type, which is more dense than ordinary stuff.
Wall framing will be standard 90x45 framing timber and likely something heavier for the ceiling rafters.
Joists. Ceilings have joists, roofs have rafters. (Using the right technical terminology is important!) And yes, you most definitely will need something rather more substantial than 2x4s (90x45) joists for the ceiling, and also for the roof rafters! Your structural engineer will calculate what dimension lumber you need for each of those, based on the live load, the dead load, the target deflection, the type of wood, and local regulations. NZ is earthquake territory, just like Chile (where I live), so you absolutely need to take into account the seismic loads that must be absorbed by the structure. I can pretty much guarantee that using 2x4 joists to span 4.2 m with the type of dead load typical for studio ceilings, is going to give you a headache when that lot comes down on your head in the first 6.something temblor... This is why you need a structural engineer: to make CERTAIN that your loads, stresses, strains, tensions etc. are safe for YOUR area, and meet all applicable code.
... use 2 layers of 50 MM Fibretex 350
Looks like it should work OK. At 60 kg/m3 It's a little on the heavy side, but still well within the useful range.
which has an NRC (Noise Reduction Coefficient) of 1.05
NRC is not really relevant in this application, since it isn't being used as a pure absorber. The purpose of insulation in the wall cavity is to damp the various types of resonance going on in there, so NRC rating isn't that important. What matters most is the low frequency absorption, so it's the columns marked "125 Hz" and "250 Hz" where you should be looking. The coefficients are 0.21
and 0.69 respectively, which is pretty good. But that's for the plain stuff. Note that for the faced stuff, those go up to 0.31 and 0.83. So it might be worthwhile using one layer plain and the other faced. Check with the manufacturer of the faced stuff is considered to be a vapor barrier or not, so you can plan on what to do about vapor barriers too...
Outer leaf will likely be a board & batten finish, so something like thick plywood for the cladding.
Don't forget the house wrap in between! And do make sure you have enough mass (surface density) to get the amount of isolation you need, at the frequencies you need it (use the MSM equations for that, along with the other equations for the rest of the spectrum).
Coloursteel roofing.
Are you SURE about that? It doesn't rain where you live? No hail either? And since you are shooting for 50 dB of isolation, how do you plan to get enough mass on the roof to achieve that when all you have up there is a think piece of metal sheeting? Also, how do you plan to seal that air-tight, and what are the regulations governing venting of roof decks? Are you even allowed to seal it? I'd say that you really need to think this roof plan through some more... You won't be getting anywhere near 50 dB isolation with that plan.
I'd like some glass sliding doors but understand those would be expensive so probably out of my price range.
If you are going to use ordinary swing doors (hinged doors), then you need to show that on your diagram: show the actual "sweep" of each door, so you can see which parts of the rooms are not usable: you obviously cannot set up mics, instruments, gear or furniture in the area where a door sweeps as it is opened, and not within many inches either. I think that, when you have drawn in the sweeps, you'll see that the Isolation booth is basically unusable (not enough "unswept" space for anything), and there's a large chunk of the live room that you won't be able to use either.
Yes i will have HVAC but haven't thought too much about that just yet.
You should! It's a big-ticket item, and eats considerably into your budget, even for a simple system with just a mini-split unit in each room, plus a fresh-air inlet duct and stale-air exhaust duct in each room, with their respective silencer boxes and fans. It all adds up...
1) I'd like the Control Room to be a RFZ but don't really know where to begin calculating that. Can someone help draw that for me in Sketchup based on my control room dimensions? Ceiling Height would be 3 metres for the entire studio
I'm sure someone will do that if you pay them to! But I'm not so sure that you'll find someone who is going to go to all the hassle of figuring that out, for charity...
The forum is mostly about "self-help": You post your own designs here, then other members take a look at it and make comments on what they think about it, how it can be improved, etc. Some members might even go so far as to sketch part of a wall, window, door, or a panel or something, to show you how to do it right. But I don't think anyone is going to design your entire studio for you, for nothing, unless they are feeling EXTREMELY generous! There's a lot of work that goes into that: days, if not weeks.
Sorry, I know that is a bit cheeky of me
Yup.
all I could really summarise was that I can't do a RFZ design until I Ray trace the control room space and work out where the angles should go based on that
It's an iterative process: start with the side walls and soffit baffles at an angle that looks good to you, then draw a circle to represent the size of the RFZ that you are aiming for, then ray-trace at various angles from the speaker and see where the rays go after the first bounce. If any of the rays get inside the RFZ circle, then change the angle of the walls a bit and try again. Keep on trying until all of the rays fall outside of the circle. Then follow those rays to find out where the second bounce will happen, and figure out what type of treatment will be needed at that point to meet the rest of the RFZ criteria. Rinse. Repeat. Ad infinitum (or until you get bored...).
And not just in 2D: You have to do that in 3D, because sound happens in all three dimensions at once, not just the 2D plan view...
I don't really know where my speakers are supposed to go
You really do need to start with that! A control room is there for one single purpose, and no other: to provide a place where the engineer can hear the SPEAKERS in perfect clarity, and NOT hear the room at all! (Or rather, only hear the room within the criteria set by the RFZ concept). If you don't know where to put your speakers and mix position, then you are in a sad situation. That is critical.
Soundman2020 posted this in another thread: ... I think he was referring to someone else's specific room anyway so it may not necessarily apply to mine.
Not really: I was referring to yours too! Notice what I said at the start of that description: "In any rectangular room, ..." and then "The theoretical best location for speakers in that room is...". So it applies to your room as well, provided that it is basically rectangular (leaving aside the RFZ shaping that comes later).
HOWEVER! (and this is a big caveat...) That is all THEORETICAL, and is only GUIDELINES. It gives you a good starting point that works for pretty much any room, but you then need to make whatever adjustments might be needed in
your specific situation. The make and model of the speakers, for example, is also important. When I'm designing a room, that's the first thing I take into account. Not all speakers are created equal: they all have different frequency response curves, polar pattern curves, dispersion angles, and other characteristics that need to be considered in the room design. A speaker with a very wide dispersion angle that is smooth across the spectrum will give you a wide sweet spot, but it will also "illuminate" the walls a lot, implying that you probably need to angle them more and treat them with more absorption up front and more diffusion at the rear (provided that the room is big enough to allow for diffusion, of course), whereas a speaker that has narrow horizontal and vertical dispersion is going to need vary careful positioning in the soffit, and you might even need to tilt the soffit down a bit to get it right, but you can get away with less absorption on the ceiling and first reflection points. But you'll need deeper absorption on the rear wall. Etc. And if you do tilt the speakers down, then you have to take into account the reflections on the desk and console, and the mid-range dip that will cause...
So there's a lot to take into account, but the basics are pretty much as I mentioned in that post, and if you follow those, you'll get something usable in most rooms. It might not be excellent, but it won't be bad either.
2) I wanted to use a 1 - 1.14 - 1.39 Ratio for the Control Room, but failed when I plugged it into this site
http://www.bobgolds.com/Mode/RoomModes.htm. I did the calculations which gave me H=3m, W=3.42m, L=4.17m and it gave me 2 passes and a fail.
3m is a bit high for a typical control room. I'd drop the ceiling a bit, to maybe 2.8m. In fact, I just tweaked your dimensions a bit, and 4.19, 3.50, 2.78 works out pretty well. That's closer to Sepmeyer's third ratio than it is to his second one (which you were aiming for), but it's smoother for a room with a high ceiling.
Also, try this calculator:
http://amroc.andymel.eu/amroc_andymel_eu_calculator.php
It's a bit more visual.
3) If I wanted the studio to be designed by a professional - How much could I expect to pay for full plans for a studio like the design kendale did?
How much money do you have?
Seriously, getting it designed properly isn't that expensive, and to be honest it will very likley save you money in the long run, as you'll avoid the typical "first timer" mistakes, which often involve tearing down something you already built then re-building it the right way... with the relevant costs in time, money, wasted materials, frustration, etc. The money you spend on a designer is money VERY well spent. It's an investment, not a cost. It will bring returns.
Most designers charge by floor area and complexity, as well as "deliverables". If you want a 3D model with basic layout, geometry, framing and initial treatment, that's one price. But if you also want full architectural drawings, detailed bill of materials, structural calculations, electrical plans, plumbing plans, foundation plans, HVAC plans, and everything down the last nut, bolt, screw and washer, then that's quite another thing. What I normally do with most of my paying customers, is to deliver a complete 3D model in SketchUp, and they then get their own architect to put that down in paper
in the format that is required by their own local regulations, in order to get the necessary permits. It makes no sense for me to do the architectural drawings, since I don't know what the local regulations are in every country and municipality on the planet, so it's best that a local guy does that. I usually don't include the Bill of Materials either, since that is something that you can do yourself, based on the model. Plumbing and electrical are other places you can save money in the design. HVAC is important, but some folks already have their HVAC contractor lined up, and he can do all the calculations probably cheaper then the studio designer would charge. Etc. So it all depends on how much of the design work you want the acoustic designer to do, and how much you can do yourself or pass on to your architect.
But regardless of how much it costs, it still saves you money and heartbreak in the long run.
So I'd suggest that you contact John himself and see if he can quote you for designing your place. Send him a PM pointing at this thread, and ask him for a quote. However, I understand that he's working on a big project right now, so he might not be able to do yours, and he might not even be able to reply. But give it a go! If you don't hear back from him within a couple of days, them PM me.
4) Do I need an airgap of 200mm between outer/inner leaf or could that be less? Note, i have 100mm gap between the studios
That all depends on how much isolation you need! You can calculate what size gap you need based on the mass of the leaves on either side of the cavity, the amount of insulation in the cavity, and the lowest frequency that you need to isolate. The MSM equations give you all of that (and the mass law equations, to a certain extent, and the other equations for higher frequencies, such as at the coincidence dip). Put them all together, and you can figure out what size gap you need for your situation, your construction materials, your design, etc.
5) I'm not sure if I need two doors for the inner/outer leaves or can use just one somehow?
You CAN use just one door, commonly known as a "super door", but it is massively heavy and involves expensive, exotic materials, such as lead sheeting. It is also pretty hard to hang, because it is so damn heavy, and it needs massively strong hinges, and very careful positioning so that it does not sag, nor twist, bend or warp the framing as you open and close it. The tolerances on the seals are tight, as well. It's a precision job needing several people to get it in place and operating smoothly.
So the answer is yes, it can be done. But the answer is no, you probably do not want to do that if this is your first time building a studio. It is cheaper, simpler and safer to go with a pair of back-to-back doors in every MSM wall.
6) Am I on the right track?
Ummm.. partly, yes. Actually, "mostly" would be a better response. You are mostly on the right track, but "the devil is in the details" as the saying goes, and it's the details where you are going wrong right now...
You have the right basic idea, but there's a lot of stuff that you need to re-think in order to get the design in order and workable.
- Stuart -
