You sure do pick 'em!
Floor - 19mm Particle board + 250 x 60 bearer + 2 x 15mm Fire-check plasterboard + commercial premises under.
So if I'm understanding correctly, your floor is just a single layer of 19mm MDF? Not even OSB or plywood? MDF is probably not a good choice for a floor.
Question: Is there any chance you could modify the ceiling on the room below?
Roof - Metal Clip-lock.
I'm not familiar with "Clip-lock". Do you have any links to the manufacturer, or photos of what that is?
We have filled in the corner with (2 leaf) walls to the south & east
How is that built? Block? Stud-and-drywall? Brick? Something else?
Also, if that is already a 2-leaf wall, and you plan to build more walls inside it, then you have a problem: you are going to end up with 3-leaf or even 4-leaf walls. Not good for low frequency isolation...
... applied a acoustic panel treatment to finalize the studio footprint.
I'm not sure I understand: acoustic panels do not define the inner leaf of a room. Acoustic panels are treatment, not isolation. They have practically no effect on transmission loss, and cannot be used to create the footprint of a studio. The footprint is defined by the massive, solid, hard, rigid inner-leaf walls. You then add acoustic panels with that inner-leaf, as needed to treat the room acoustically.
This plan was our first new design.
I'm glad you changed that! It would not have been very useful, acoustically.
Then finally to this plan which we will start to refine.
That's an improvement, but there might also be other layouts. The live room area seems rather small, for example. You show space for at least a dozen people in the CR, but barely enough space for two in the LR.
Also, if I understand your drawings correctly, the ceiling is much lower at the back of the control room, and higher at the front: that is backwards form the way it should be. The ceiling should be lowest at the front, over the speakers, and highest at the back, over the couch.
This studio will be used for all sorts of genres.
OK, but how loud are you inside, and how quiet do you need to be outside? Those are the two key questions that determine isolation. You should measure those levels with a sound level meter, set to "C" weighting and slow response.
We have to keep the door which accesses the stage with a small staircase from the studio.
There's only one door there, so you won't get much isolation from that. You need two doors, back to back, one in the inner-leaf, the other in the outer leaf, to get decent isolation. One door alone will not do it.
Since there is a suspended acoustic ceiling in place, our thoughts are to create a new ceiling underneath this.
As long as you remove the suspended ceiling first, then yes, that would be a good option. If you leave that ceiling in place, you will have a 3-leaf ceiling, which is not good for isolation.
and the South east walls are 10mm plasterboard + 90mm timber frame + fiberglass insulation + 10mm plasterboard.
As I suspected, you already have a two-leaf wall, and a very thin one at that. You won't be getting much more than about 25 to 30 dB of isolation from that. You need to modify that wall to make it into a single leaf again, so you can build your inner-leaf next to it. To do that, remove the drywall from the side facing your studio, take out the insulation carefully (you can re-use it), then cut strips of 16mm drywall (plasterboard) to fit between the studs in that wall, hold them in place with cleats, and caulk all around the edges, carefully, with acoustic caulk. Then repeat that with another layer. Then put the insulation back in. That will give you the necessary mass for your outer leaf.
The plan shows a separate wall within the studio for both the CR and the vocal booth.
Exactly. Each of those needs its own individual inner-leaf, built as a stud frame with drywall on only ONE side, and not connected in any way to the existing structure: In other words, the inner leaf of the CR cannot touch anything except the floor, and the inner-leaf of your booth cannot touch anything except the floor.
-We need help in working out our ceiling construction.
With your inner-leaf walls in place, install suitably dimensioned joists across the tops of those walls, and suspend at least two layers of 16mm drywall from that. Once again, the new ceiling cannot touch any part of the outer-leaf: it rests only on the inner leaf walls.
- We need help with the option of a suspended floor.
I think you mean a floating floor, not a suspended floor: two different things.
You might want to read this thread, if you haven't read it already:
http://www.johnlsayers.com/phpBB2/viewt ... f=2&t=8173
If you do decide that you need a floating floor, you'll need to call in a structural engineer to tell you how much extra load you can place on your existing floor structure, and how to beef it up if needed. Floating a floor is a pretty tough undertaking, and the floor will be very heavy, so this is a must: you do need a qualified structural engineer for this.
- If you notice in the elevation that the ceiling is sloped upwards towards the CR window. Is this a problem since I notice many studios around the world have either a level or sloping in the reverse direction ceiling.
I mentioned it above, before I saw your question: yes it is a problem. The control room should only ever get bigger as you go back, not smaller. At the least, it should stay the same. Ceilings and walls with "reverse" angles are going to give you problems with attaining a good reflection free zone around the sweet spot. However, you can solve this problem with the inner-leaf ceiling that you need to build anyway: that can be angled correctly, or it can just be flat, depending on your design philosophy.
I didnt realize until last night that the 'John Sayers Productions' writing up on the top right of the forum was a button that took you to a wealth of great information.
Oh yeah! This place is a gold mine of very useful information about acoustics and studio design! The more you look around, the more you keep on finding new stuff.
Its a DYI project with a bunch of us putting our heads together.
That's the way many projects are here, so you are in good company! I'd suggest that you get two excellent books to help you out here: "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. The first one ("MHoA") is a great text that takes you through the basics of sound and acoustics, touching on all the theory you need to know, but in a clear, easy to follow way. The other is more of practical "how to" guide, the leads you through the actual design and construction process.
So, to summarize: you should start be setting the isolation goals for your studio: The most basic question you need to answer its "How many decibels of transmission loss do I need?": Based on that, the rest just sort of flows together...
- Stuart -