Congrats on closing! That's good news.
most of the walls (all, probably) will be of the 'standard' 2layers drywall w. Green Glue + 2x4 + 2x4 +2layers drywall w Green Glue (double leaf setup)
and I'm curious about what would (could) bring that design up to the 'next level' of isolation.
Only two things: 1) More mass on each leaf. 2) Larger air gap between the leaves. Either one, or the other. Or both.
there is a sort of main wall (on the drawing with the red oval over it) btw the studio and the rest of the building, and i'm curious to get your input re: making that wall better, isolation-wise.
this is potentially the one spot where i could actually use some more isolation..
You cannot increase the total isolation of a studio by improving only one wall. Isolation is "all or nothing". The overall isolation is only as good as the weakest link. Not sure if you've seen my analogy of a fish tank before... if not, do a search on the forum for "aquarium", and you'll probably find it. A few times...
1 more space btw the two leaves (i.e. the 2x4 frames) = i've got some room here, so.. would 12" be a dramatic improvement, over 1"?
It would lower the resonant frequency quite a bit, yes, which will have an overall positive effect for THAT wall, but won't do much for the entire studio! You would need to do the same to the other walls, and the ceiling, and the doors, and the windows, and the HVAC system, and the electrical system...
2 more insulation btw the two leaves (for example: if nr1 is true, would one then fill that 12" gap with insulation?)
You ALWAYS fill the air cavity with suitable insulation, no matter how big or small it is, if you want maximum isolation. The purpose of the insulation is to damp internal resonances going on inside the wall cavity: no damping = worse isolation. The insulation fundamentally changes the way sound moves through the cavity: putting insulation in the cavity changes the process from adiabatic to isothermal and reduces the speed of sound by a factor of around 30% (debated). Look at the fixed "constant" in the MSM equations: it changes from 60 if the cavity is empty, to 43 if you fill it with suitable insulation. That alone should tell you something... If you don't fill the cavity, then you would have to set it higher than 43, which obviously implies worse-than-optimal isolation...
3 more / different material on the wall itself? 4 layers of drywall? or, one layer of drywall and one layer of something else? Like QuietRock?
Mass is mass. Sound waves cannot read price tags, and won't be impressed if you pay more than you need to for the mass. All the sound waves see is "kg/m2". The higher that is, the more they are attenuate. The price tag does not influence the mass. So get the cheapest mass that will do the job.
4 different types of insulation? (R13 fiberglass seems to be the norm... is there a better choice for studios?)
Use the type that best fits the application! You need the type that has the correct acoustic impedance for the job you want it to do. In other words, the greatest damping at the lowest MSM resonant frequency of the wall system. That will probably be in the range of around 7,000 to 10,000 MKSrayls for your ultra-thick wall, with very deep insulation. Perhaps a little lower than that, considering the thickness and very low frequency. I would suggest probably OC-701 or OC-703, but it's gonna be real expensive to put 12" of 703 in all of your walls and ceiling! It might be an idea to go with a slightly less capable insulation that is much cheaper. Unless of course you have very deep pockets, and don't mind blowing tens of thousands of dollars on insulation alone.
just looking to see what you think would be the next level, as it were...
Your diagram is faulty in several ways:
1) it shows that you have several "things", which I assume are support posts, connecting the junctions of some walls between rooms: that wont work. The support pillars would have to be totally inside the wall cavities, not touching any of the leaves. The way you show it would trash your isolation.
2) It shows that your "CPU room" (do you mean "machine room"?) is not isolated from the CR. That would likely be an issue if you have noisy gear in there, such as a few computers with large hard disks, and fans....
3) You have the client couch right up against the rear wall. Read "Acoustic Absorbers and Diffusers: Theory Design and Application by Cox and D'antonio to find out why that's a bad idea.
4) The client couch is not symmetrical in the room: someone sitting back there is not going to get a balanced stereo image.
5) You don't have any bass trapping at all on the rear wall! And no diffusion either! What is your design concept? It looks vaguely like it wants to be RFZ, but the speakers are not flush mounted and the angles don't work for that, so that can't be it... Also, the "CPU" door is in the way of where your soffits would need to go. So it isn't clear what design concept you are using as the basis for this room.
6) The rear corner bass traps appear to be the only ones, which means they are far too small for that room. You'd probably need about five to ten times the volume you show there (unless this guy can make his magical physics-defying bass trap work! (
http://www.johnlsayers.com/phpBB2/viewt ... 7&p=145926 ). Have you read ITU BS.1116-3? It doesn't tell you what design concept to use, or how much bass trapping you will need, but it does lay out the full range of acoustic specifications you will need to meet in your room, if you want to use it for critical listening. That, in turn, will point you in the right direction...
7) You don't seem to have any sight lines from the mix position or the client couch into the vocal booth.
8 ) Your mix position layout doesn't seem to make much sense at all... more detail needed to see what is actually going on there.
9 ) Your amp booths don't seem to be isolated.
10) You seem to have some type of huge door, about the size of a garage door, into the LR at the bottom left of the diagram:
How do you plan to isolate that? !!! If you do that, you certainly won't be getting much isolation.
11) What is the rectangle marked "EL" at the bottom center of the diagram?
just looking to see what you think would be the next level, as it were...
Overall, I'd suggest that before you strat thinking of "next level", you should define "this level"!
In other words: define how much isolation you NEED, define your CR design concept, define your room volumes and floor areas, define your basic treatment, then update your floor plan to reflect that, and also move form 2D into 3D. Once you have that in place, you can do teh math to figure out how much isolation you will actually be getting with the current design, compare that to how much you need, and then decide if you need to go for the "next level" or not.
Hope all those comments help!
- Stuart -