Yeah, I'll TRY to be patient.....anything I can do in the meantime that won't mess things up, like starting on the west side knee-wall? BTW, I'm really really curious to know why you don't recommend RC.......
Yes. Quite as few really. Under normal circumstances, I would recommend it.
However, your situation is governed by your floor membrane plane and simple.( was that a pun?...hahahahaha)
And I'm sorry I suggested the use of it in earlier replys. Hindsight is 20/20, and after further analysis of your situation, it appears my earlier advice is not aligned with the facts of your situation. Although RC certainly may help, at this point I have to consider some additional information you have provided.
Namely, you are not recording live drums nor bass, nor lMarshall amps on 10, or a full band. This situation would require every technique available, not to mention tons of mass AND money.
Understand my view is coming from simple intuition, common sense, and my belly.
However, I will explain.
1. Simple physics(I don't claim to understand physics on a academic level)dictates that LF resonance or even plain sound waves will vibrate your floor as it is a membrane. Especially at certain frequencies. Under normal circumstances, given a studio with a SLAB as a floor plane, sound has little effect on the mass, as it is DAMPED by the earth. Although, structural transmission can occur as a result of impact, simple airborn sound has little effect on concrete slab floors, and what effect it DOES have is simply negated by decoupling the slab from the foundation footing which the building envelope rests on. In that situation, the use of drywall decoupling makes all the sense in the world.
. Your situation allows no such mass, let alone damping, let alone total decoupling. That is why I suggested the use of the KIP flooring as a partial solution, although I am absolutely sure, resonance can induce transmission to the building envelope regardless of a "decoupled
So, in essence what you have is a membrane which is structurally connected to the surrounding envelope. No amount of decoupling of the wall/roof envelope from the structural support will keep the floor membrane from vibrating at certain frequencies, as the entire envelope will resonate at certain frequencies, because there is not enough MASS in one plane to decouple the rest from....ie..a SLAB.
2. Practical elements of actually implementing RC with your building envelope
conditions....ie...sloped walls, angles, and multiple layers of drywall. RC is easy to mount on the framing under normal circumstances, and with a modicum of pre planing, storyboards, and common sense, even a layman may successfully fasten one layer of drywall when the room envelope is a normal box. However, the next layer becomes exponentially difficult to fasten as now the RC is hidden. Even with EXACT layout lines, the possibility exists for ONE screw to COUPLE the drywall with the external framing, which if were to happen at a critical connection may undermine the whole ball of wax.
Now add the following elements and it will become blindingly obvious why installing RC in a studio such as yours would require the UTMOST in preplaning EVERY SINGLE DETAIL. I believe even Rod would agree that when RC is dictated by a designer, NOTHING is left to chance, and the tradesman are under CONSTANT supervision to assure complete success. Even under nomal circumstance, the chances are great that the RC is compromised, even partially. I have read tests of an RC installation that was DE-constructed whereby PROFESSIONAL installers made numerous errors, although the installation was not totally compromised. Something about how many drywall screws connected with the framing.
a. Details at the door jambs
b. Decoupling of HVAC duct regesters/grills(you've now
penetrated a decoupled interior envelope that you've tried so hard to install correctly. Now you connect a duct regester that is tied to a structural element above.
....ie...decoupling the register from the strutural element as well as the drywall)
c. There is no sense in decoupling the drywall and leave the floor membrane UN decoupled via a roll out/tile product with integeral vibration decouplers. Therefore, IF RC is to be installed, a DECOUPLED floor product must be part of the overall package.
Now, the detail at the drywall, decoupled floor must be addressed, as well as the installation sequence/ baseboard decoupling/ and DOOR threshold seal details too.
Now add these little nuggets to the problem at hand.
1. Your sloped walls...you now have hanging mass that is NOT depending on SHEAR of the drywall screws for seperation from the RC, but depending on the NON PENETRATION of screws through the drywall membrane sheet. Which under PRO use of the correct drywall screw fastening tools is probably not a problem. However, DIY use of a common drill may preclude success, as even I, being as carefull as possible have routinely driven screws though the facing sheet of drywall, although it hardly mattered given the project at hand, AND there were a thousand other screws providing SHEAR protection.
I know this seems rediculous...but consider the drywall is now HANGING at an angle. Not only that, but given the added mass of a second layer, you now must consider this weight PULLING the RC flange OUTWARD. Maybe this is a problem, maybe not. I personally have never delt with it but in MY mind...I AM a long time aquaintance of MURPHY!
Needless to say...I am apprehensive.
2. Angles. Consider this. At the west wall roof plane, fastening RC to the roof framing 2" above the floor will be an excercise in fastening frustration. To drive a screw in perpendicular to the roof plane would be IMPOSSIBLE, unless you had a RIGHT ANGLE DRILL.
And then you have the angle at the web frame cieling plane/roof wall intersections. Under normal wall/ceiling drywall intersection conditions, this joint can be offset by an 1/8" or so as the connection is at a right angle, and can be easily caulked, and the next layer installation sequence will cover this gap and will allow ANOTHER 1/8" gap to be caulked. HOWEVER, with angles such as yours, butt joint gaps will be a totally different configuartion, requiring very accurate drywall cuts, which knowing how common carpenter framing is, may be easier said than done, as the ceiling PLANE framing may NOT be perfectly IN LINE. Should this be the case, this would require custom cutting of each piece, if in fact custom SCRIBING each peice as one can imagine not only is the ceiling drywall HANGING on RC, but because of small inconsistancys in the framing PLANE, the WIDTH of this ceiling panel now will be slightly CURVED at some points, as these inconsistancys in the plane may cause not only the RC to BEND to compensate for the non flatness of the ceiling plane, which in turn requires the drywall panel to BEND when fastened to the RC.
NOW, when the roof drywall is DIMENSIONED for cutting, the edge of the ceiling plane is NOT a straight line. It bends up and down like a scribbled line.
This may be a worst case scenario, but SHIT HAPPENS, and dealing with it down the road, especially when it comes to trying to screw dryall, to a 1/2" RC flange, while maintaining a 1/8" gap at NOT ONLY, the ceiling, but at the KNEEWALL intersection as well. TALK ABOUT A FUCKING NIGHTMARE!!
And thats just the first layer...geezus...how do you spell....hmmmm....did I mention TONS OF CAULK for NON LINEAR GAPS!! Not to mention curved joints when it comes time to TAPE and MUD!!
Murphy would dictate that when installing the RC on the ceiling web frames, I would HIGHLY recommend stretching a string across the complete length of the room, up against these framing webs, prior to actally installing the RC. And THEN, if inconsistancys require it, to SHIM the RC to achieve a FLAT PLANE. Even then, small width inconsistancys may STILL require custom trimming of each piece of ROOF WALL drywall. IN FACT, if it were me, I would probably use a utility knife or sanding block, to manipulate the edges of both the ceiling dryall AND the roof wall drywall into a OVERLAP MITER.
This would insure no gaps whatsoever. The roof drywall would actually overlap the ceiling AND kneewall drywall in such a way where there would BE NO GAP. Remember, airtightness is part of the overall TL strategy. Should you opt fo simple butt joints allong the kneewall/ceiling intersections, given TWO layer buttjoints, his situation alone could be a gap CAULkING nightmare.
Ok, NOW, consider where these kneewall, ceiling and roof plane drywall panels meet at your NORTH wall. Now you have another situation Think about it. Not to mention, should you decide to use MY rear wall design solution for a symetric rear wall, now you would have COMPOUND ANGLE intersections....consider the angled portion of the rearwall where it meets the roof...
hmmmmm, custom cardboard TEMPLATE layouts come to mind.
Ok Robn, I have a situation at home I have to take care of immedietly(father in law health problem), so I have to leave now. I'll be back with a ton of illustrations and other opinions. Later(sorry I couldn't finish at the moment but I believe you get my drift here.
PS. Solution. Two layers of 5/8" drywall fastened DIRECTLY. Mass is my suggestion. Same at floor. btw, blocking at these intersections will allow for easier fitting and fastening. AND a kneewall at the west roof.
Pulled his catheter out in the middle of the night..ripping a blood vessel, filling his bladder full of blood..and miscel other things...all because of his damn stubborness..and thinks he KNOWS his own body and can make what ever decisions for himself what EVERY it causes to himself and other people. Damn him sometimes. Now my wife has to stay at the hospital all day cause hes going into surgery immedietly. Now I don't have help finishing the days painting. 
I'll be back as soon as I can. Gotta go work now.
