Hi there Vinny & Una, and Welcome to the forum!
My main incentive in this project is that we build a really good sounding studio for little cost in materials, so that we can put maximum money into equipment.
This is just my personal opinion, but I would actually do things the other way around: I would spend most of my money on the acoustics, and only some on gear. You can pick up very good quality gear for low prices on e-bay, but you can't pick up very good quality acoustics like that...
I would spend a couple of thousand of that to get good speakers that are suitable for the room, then spend most of the rest on acoustics. You can have the best speakers in the world, but if the acoustic response of the room is lousy, then those speakers will sound terrible. On the other hand, if you have a room with great acoustics, then even mediocre speakers will sound good.
It is HEAVILY insulated on all faces with 200mm of polystyrene boards, then faced with about ~60mm of reinforced concrete on all faces except the ceiling. All original walls behind the insulation are solid mass concrete and about 200mm thick.
The reason you are getting such good isolation is the thick concrete and the large gap between the walls. The polystyrene is doing nothing useful there. It is great for thermal insulation, but pretty useless for acoustics. But the good thing is that you are already getting good isolation, so there's no need to touch that.
The ceiling is corrugated steel (I sensed you shudder!) which is attached to 45x70mm timbers which are suspended by threaded steel bar from the main roof structure, which is made of much larger 120x45 timbers spanning the full width of the room.
And what is above that? What is the roof made of?
Photos would be helpful to understand the building better.
So from the above I assume that soundproofing of the space as a whole should not be needed.
It sounds like you have good isolation, which is excellent since you don't have enough budget to add more!
I have attached a file which is a first draft ...
I think you forgot to attach that! There's no attachments at all on your post...
My task now is to try and re-design the space so that it will be OPTIMAL, before we start building.
Before you start re-designing, I'd suggest that you get 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. Those two give you the basic knowledge you need to get started on designing a studio. The first one will give you what you need to know about acoustics, and the second one is more about the actual design and construction.
We have most of the building materials now so it's just a matter of finalising the plans!
It's probably more a matter of learning about acoustics and studio design, THEN finalizing the plans!
And here is how we are planning to build the internal walls;
Ummmm... you already
have your internal walls.... you said that the room is built "
faced with about ~60mm of reinforced concrete on all faces except the ceiling. All original walls behind the insulation are solid mass concrete and about 200mm thick. So you already have
both of your walls: the outer-leaf is the 200mm thick concrete, and the inner-leaf is the 60mm concrete. Adding more leaves to that can potentially DECREASE the isolation of low frequencies....
Firstly vertical timbers at each wall reaching up to the timbers which support the steel ceiling.
"reaching up to" is fine, as long as they don't touch. Assuming that you really do want to build interior walls, and don't mind the potential loss of isolation, then you cannot allow your new structure to touch any part of the existing structure. If it did, them yo would have even less isolation, due to the flanking paths. So your new extra inner-leaf walls can go almost up to the existing ceiling, but bot quite, and your new inner leaf ceiling must rest on top of those new inner leaf walls without touching anything else.
Staggered studs 600mm spaced,
Why so you need staggered studs???? That implies you are thinking of adding TWO new leaves, not just one!!!
That would give you FOUR-leaf walls, which are even worse at isolating low frequencies that 3-leaf walls!!! I would suggest that you really need to pause in your plans, and buy those books to understand why you should only ever have 2-leaf walls, never 1-leaf, never 3-leaf, and certainly never 4-leaf....
built as two separate walls on top of a pair of 75x45 planks with 10mm gap between them
Just as I expected: that would give you 4-leaf walls... A really bad idea. Don't do that.
one layer of 12mm sheetrock on each side
12mm is too thin. Use only 16mm. 12mm is too flexible, the mass is too low, and the resonant characteristics.
followed by a second layer of 12mm sheetrock attached with green glue
Sorry, but that would be a major disaster. You cannot use Green Glue to "attach" anything! It is not glue! it does not stick. It is not adhesive. It is a viscoelastic polymer material that is specifically designed to act as a constrained layer damping compound between two layers of drywall or similar. It is NOT glue. You CANNOT use it to attach the second layer of drywall. Yes, you use it in between the layers, as directed by the instructions, but then you use either screws or nails to attach that drywall to the underlying studs, in the normal manner.
Not sure yet on the finishing of the walls.
Most people just tape and mud them, then sand and paint. Most of the surface will be covered by acoustic treatment anyway, so you won't see much of the drywall once the room is finished.
floor 2/3 of the space
Floor??? What floor? You already have your final floor in place! There is no need for any additional flooring. You said that the current floor is concrete, which is excellent. There's no better floor than that for a studio. If the concrete is in really bad condition (cracked, chipped, uneven, badly stained, then you might want to put down something like laminate flooring, ceramic tiles, or linoleum, but that's about all. The final floor surface must remains, solid, massive, hard, and reflective.
and cover a ceiling or two in nice pine.
Your ceiling should be the same as your walls: two layers of drywall together, screwed or nailed to the joists, with Green Glue in between. The ceiling wont be visible once the acoustic treatment is in place.
As for the floor we plan to lay tongue & groove Pine ... in the live room and control room on supporting timbers which will rest on a thin foam for cushioning/damping...
That's a really, really bad idea. That would basically mean that your studio floor would be a drum. It would be a resonant nightmare.
It seems what you are trying to do is to make a floating floor, but firstly you do not need one at all, and secondly that is not the correct way to build one, even if you did need it. Here is a very important thread that you need to read about floating floors:
http://www.johnlsayers.com/phpBB2/viewt ... f=2&t=8173
As for ceilings, we plan to remove the corrugated steel at least from above the live room and replace it with thin pine planks.
Why
You already have a steel ceiling that is giving you good isolation, and you plan to replace it with thin wood that won't? Please don't take this the wrong way, but you are not thinking this plan through very well. I would strongly urge you to stop all your plans right now, read through those books, the re-design the studio based on what you learn there. You are going about this entirely backwards, and you seem to be basing a lot of your plans on myth, misinformation, guesses, and internet lore. That's a really bad way to design a studio!
Fortunately you found this forum before you started to build! So now you can learn how to do it right.
And for the other rooms we were planning to build lower suspended ceilings
You want to make your ceilings LOWER??? WHY? Good acoustics needs large open spaces. Lots of air, lots of ceiling height. As much as you can get. There are people here on the forum who spend a lot of money to break out the floor in their rooms, dig down some more, then pour new concrete floors lower down so that they can have HIGHER ceilings. But you want to have
lower ceilings?
Once again, you really need to read those books and get a better understanding of acoustics before you design or build your studio.
1. SOUNDPROOFING: Based on the rudimentary leak test that we did, are we OK to assume that the space will not suffer from external noise? Maybe this is impossible to answer without SPL readings...Noise getting out is not an issue where we are, on a harbour in a tiny Fjord in the wild East of Iceland
From what you say so far, it seems that you have reasonably good isolation, with the possible exception of the ceiling. However, you just mentioned "harbour", which makes me think of large diesel engines on both ships and trucks, as well as fog horns and other noisy things that happen around harbours.... are you SURE that your isolation is good enough to prevent those noises getting into to your studio, and messing up a recording? What about other noises? Wind, rain, thunder, aircraft, helicopters, trains, people, etc. There are many noises that could be a problem if they get into your studio.
2. FLOOR PLAN: From recent feedback I think we need to scrap our first draft completely! Please can you give me any ideas on a possible floor plan. I am thinking of starting with the control room in the top-right, live room still taking up most of the left half, then iso rooms below control room.???
You didn't attach any diagram, plans, sketches or photos, so we can't see what you had in mind, and we can't see what is on the "top right" or the "left half"!
3. WALL STRUCTURE: Are we over-building the walls? Is it enough to just use a single plank base and stagger the studs on that? We do have enough timber collected to do what we had planned so it would be no extra cost to do double... sheetrock will be the money zapper here I think!
It's not that you are over-building them, or under-building them: You are just not building them correctly. They would probably male your low frequency isolation worse than it is now, not better.
4. FLOOR STRUCTURE: Should we be considering a certain method here when applying a timber floor on top of a concrete one? Bearing in mind that under the concrete there is 200mm of polystyrene insulation before the actual mass-concrete floor...
Yes. The method you should be considering is "leave the floor alone!"
It is concrete, it is thick, it rests on the ground, so it is prefect. It does not need anything else. The only exception is if the concrete is in poor condition, in which case you can lay something directly on top (no air in between), such as ceramic tiles or laminate flooring.
5. CEILINGS: Should we remove the corrugated steel ceiling from the whole space and replace with something else, or is it possible to leave it and fit suspended ceilings in some of the spaces? I know it would probably be nasty acoustically and would resonate at all sorts of frequencies, but if we have insulated suspended ceilings this might not be an issue. We really wanna keep the full 3.4m height in the live room...
If you remove it, can you gain even more height? You mentioned beams and other things up there, above the metal, but what is above those? How much more room could you get up there?
But probably your best plan would be to do nothing: You don't have a big enough budget to do anything up there.
Any constructive feedback would be greatly appreciated! So please, air your thoughts
The three biggest issues I foresee here are firstly that you need to stop and learn some more about acoustics before re-designing your studio, and secondly that you have not mentioned anything at all about the most important issue in any studio: HVAC. You need that. You MUST have ventilation and air conditioning. You cannot have a studio without that. Studios are sealed air-tight, so there must be a properly designed HVAC system in place, to provide the air that people need to breath, and to evacuate the stale air, and also to control the humidity, as well as the temperature. You didn't mention that at all, but it is a major, important part of the studio. And it is expensive. Which leads to the third point: your budget. You mentioned a budget of about 10,000 Euros, but you want to spend most of that on gear. Assuming a 50/50 split, you would have 5000 euros and a floor area of about 80 m2. That means you have about 60 euros per square floor of floor space. That's not enough. Not close. Just your HVAC system for that size studio is going to eat up about 3000 to 5000 euros, and probably more, even for a very simple system. I would suggest that you will need to greatly increase your budget, if you want to do this right. You will probably need more like 200 to 300 euros per square meter, at the very least, to do a studio that size with good acoustics.
So those would be my suggestions!
But please do post the initial layout that you mentioned, as well as a few photos of the building (inside and outside), so we can better understand what you have, and what you are planning to do.
- Stuart -
