I've decided that I will be flipping the CR around 180 so that the back wall will be the one with the outer window in it. I think this would really make use of that 12-14" behind the inner wall.
Symmetry is critical: You must be centered, and the room must be symmetrical about your: left half = mirror image of right half. However, that does NOT mean that the door has to be centered! You can still have the room symmetrical, acoustically, with the door off-center if it has to be off-center for other reasons.1) Does my listening position need to be in the middle of the room or can it be put offset and more towards one of the corners?
Absolutely, yes! One door in each leaf, back-to-back, with an air gap between them. And they can both have glass in them, if you want to have good sight lines between the rooms.2) For the doors, I was going to go for two separate solid core doors instead of just one massive one. Does that work?
Right.I would get better isolation by not having two separate openings and combining the two (window and door) together correct?
You can do that if you want, but if you also want to soffit-mount your speakers (highly recommended!) then I don't see any place to put the door! It would have to go in the middle, between the speakers.I was hoping to have the window in front and above my mixing position
I would really, really try to keep the glass in there. Visual interaction during the session is almost as important as talking to each other: you can make hand signs during a take, without interrupting the rhythm and vibe of the musicians, such as making a sign to "repeat the chorus again" but without stopping the flow of the session to chat, or visually cueing a musician to come in at the right point with a finger countdown, or whatever. Personally, when I'm tracking I like to have visual contact with the musicians, as well as intercom.I might even skip out on the window because the main idea is to be able to interact with the people on the other side.
Here's a couple of photos from a studio that one of my clients in Australia built, showing how sliding glass doors can work for this. The soffits are on either side of the door:
View from the control room to the iso booth:
And in the other direction, from the iso booth to the control room:
There are two sliding glass doors in there, one in each leaf.
Yes. Or you could put them overhead, if there's space up there. In the studio shown in the photos above, the silencer boxes are between the joists in the ceiling above the iso booth and between the wall, and the angled wood "thingies" along the tops of the CR walls hide the internal ducts that lead from the front of the room to the back, where the mini-split is.1) About the silencer boxes, 11 inches thick is doable. I have 12" on the plan right now but can space it a little more to accommodate. I was planning on having approx 16" in between the CR and LR walls so there would be plenty of space there I think. Could I not just fasten the boxes on my outer or inner leaf wall without them touching anything else?
Here's a view of the completed iso booth inner-leaf ceiling, before the treatment went in, showing where the HVAC duct comes in from above (you can also see the space where the doors will be later, with both leaves visible):
And the other silencer, at the other end of the ceiling:
Here's a view of that silencer in place, taken with the camera sitting on the floor looking directly up. You can see the silencer box in place, the flexduct that feeds it, and the wooden "sleeve" on the silencer that will poke through the ceiling. This was taken just before they put they final ceiling modules in place, closing off the inner-leaf completely (both the walls and the ceiling are built "inside out" in this studio, which is why you can see the inner-leaf studs and joists, even though the room is finished).
Here's a view of the silencer box going in, long before they framed the iso booth walls and celing. You can see how it fits in between the outer-leaf ceiling joists, but without touching:
... and comepltely mounted in place, on its nylon support straps with Sorbothane pads, to fully isolate it from the outer leaf:
Another view of one of the silencer boxes in place:
In that one you can clearly see the "sleeve", which is part of the silencer box, that will extend down through the inner-leaf ceiling, to the register. That sleeve is also isolated from the inner-leaf: the hole that it pokes through is a bit larger then the sleeve, so there's a gap all the way around, and that gap is filled with abundant highly flexible, soft caulk, to create the seal. Here's a view of that caulk around the sleeve, just before the ceiling module was raised in place around it:
... and around the edge of the hole in the ceiling module, just before it went up around the sleeve:
Frank did something similar for his studio, except that I designed it from the ground up to have decent space for the silencer boxes above the rooms. You can see the silencer boxes poking through the ceiling in his thread, I think. If not, I'm sure he has photos of that, so you can see how he did it.
I like to keep them both at the top. It makes sense to put the return at ceiling level, since warm moist air rises, so that's a good place to suck out that stale air and send it either back to the AHU, or dump it overboard.2) About Supply and Return vents. I've read that it's best to have the supply at the top of the walls or in the ceilings, what about the returns?
Careful with your duct sizing! It's fine to run 6" on the "far" side of your silencer boxes, either inside the wall cavity or outside the outer leaf, but for ducts inside the room you MUST keep the size large enough that the speed is low enough to not create any noise, while still moving the correct volume of air. I try to avoid using ducts inside the room, and just put the registers directly on the ends of the wood "sleeves", that are basically extensions of the silencer box into the room. That allows you build the sleeve with the correct dimensions to keep the flow rate high enough while keeping the slow speed low enough.I'm thinking of running mostly 6" insulated flex duct from the main supply and return trunc in between the walls in to silencer boxes and then out back to flex duct to the vent opening.
Yes it is an issue, and as I mentioned in my post just above, the easiest way to deal with it is to build a structural box frame over it, with the wall on top. Part of that "box" will extend into the room, and be covered with OSB, MDF, plywood, drywall, etc. The wall will sit on the back edge of that "box", and extend upwards, also supporting the ceiling. So the box is structural (load bearing) as it must support the inner-leaf wall AND the inner-leaf ceiling. At some point you will need to hire a sttructural engineer to take a look at your existing floor, and tell you just how much extra load you can put on it. VERY IMPORTANT! Don't build ANYTHING without having a qualified, certified structural engineer give you his professional opinion in the form of a written report.1) Does having my HVAC supply trunc running on the floor an issue. (You can see what I mean by last two pics I posted as well as the pictures I posted on the first or second page) The trunc is approx 10" high x 12" wide and currently sitting on 4" of insulation so it's approx. 14" off the floor. I plan to run the return trunc in between the CR and LR wall.
Yes!2) Can I still do bass trapping at that height with some fancy framing or does the bass trapping need to be done right off the floor?
Yes, but if you have a noise problem with those, you might also want to wrap them with MLV. This is one place in studios where MLV does have a use that justifies it's high cost. It might or might not be necessary, depending on how much isolation you need.3) I've mentioned that I was thinking/planning on wrapping the main supply and return truncs all around in 4" mineral insulation, Would you say that's a good idea?
Our forecast is for 34° degrees today... CELSIUS! I hear you guys are getting very icy conditions right now, with worse to come. I've been to Canada quite a few times (my sister in law and family live in Ottawa, and I've done business in Toronto and Montreal. I remember being in Montreal right after an ice storm, and they told me it had been down to -60° the week before... It was "only" -30 that week.... I don't know how you guys can even survive in those conditions! Suckers for punishment, I guess! If it goes below -2 or -3 here, that's COOOLLLLDDDD!Cheers from freezing Canada!! lol
- Stuart -