Here are my questions regarding soundproofing.
I've already purchased the 12' 7/8" tall x 2.5" wide hat channel and have been in contact with Ted at thesoundproofingcompany but my questions go beyond the scope of how much he is able to help, so any effort to answer these questions "before" I start installing the ceiling and redoing the walls (again) would be much appreciated.
Any help you can give in any way would be much appreciated:
Do I start the clips/channel at each end/edge of the ceiling and each corner and edge of the soffit(s) or literally 6" in with no support at the edges? If 6" in, why is that the spec and why is there no support at the edges? I need support near the edges of the soffits to attach things like crown molding.
On the existing soffit (right side wall) that is covering wires and pipes and cannot be framed "after" the ceiling, rather must be part of the ceiling itself, should I start the channel at the bottom edges and corners or a certain amount above bottom edge and in from bottom edge of height/corners?
How many extra clips should I use to hold bass traps and a future star ceiling which will be made out of OC 703 (3lb / sq ft) or similar material? I'd like to use two layers if possible, which would be 6lb / sq ft. How many extra clips can I use before soundproofing/TL suffers?
How many extra clips should I use to hold a cloud above the stage which will contain OC703 and lighting?
How many extra clips should I use to hold the not yet built left side wall soffit for HVAC and should the soffit be made out of MDF or OSB or just standard drywall - which is best? If it doesn't matter and the performance would be the same, I like the "frameless soffit" idea as it seems easiest and quickest to build and gives me a good way of screwing on the crown molding since it's made out of OSB, but I want to build what gives me the best TL if there's a difference.
Should just the outside walls be built, then the ceiling, then finally build the inside walls after the ceiling is finished screwing the top plate for the interior walls to the ceiling to keep the decoupling or should both sets of walls be built then build the ceiling just inside the interior walls? If the latter, then there would be no ceiling (and there would be a gap all the way up to the bottom of the subfloor above) in the space between the two sets of walls. What is the best way and proper order to build the ceiling and interior walls? Does it matter or make a difference either way?
How far apart is the proper screw spacing for ceiling, soffit, and walls?
I can only afford 1 tube of gg per sheet of drywall, if that. I may not be able to do the gg at all on the ceiling, depending on the rest of the material costs. I definitely can't afford 2 tubes per sheet. Will this make a significant difference in the ceiling performance? At what frequencies, roughly?
Which brand (if that matters) and which type of screws are suggested - how many screws per clip and how long should they be for the clip, which length for the first layer of drywall, and which length for the second layer of drywall for the soffits and the ceiling?
Is it better, worse, or the same to use 3/4" osb for first layer of the ceiling so I have an easy place to screw stuff to?
The video will explain this (by showing it) much better, but I need to know if it would be better to take down the existing outside walls and reframe them with IB-3 clips under the headers so both sets of walls are decoupled? Is it better to have BOTH sets of walls decoupled or would it make a difference if only the inside walls are decoupled? The existing outside walls are built just plain wrong in every way. They are coupled "everywhere" and are 16" on center, the drywall is on the inside instead of the outside, etc. So I don't mind tearing them out and redoing them if it will make a difference, but the question is does it matter or make any difference as long as the inside walls are built correctly, or would it be best to just tear down the existing walls and start over? SEE VIDEO:
Again, the video explains this much better and makes much more sense, but is it ok to run two HVAC supply ducts in one extra wide (2') decoupled soffit? I was thinking of bringing one supply duct (6" insulated flex) from the rear left of the theater (in from the top corner of the wall instead of down through the ceiling) and bringing the second supply duct in from the front left of the theater (again, in the top corner, through the wall, not down from the ceiling), each passing each other in the same 2' wide soffit so the duct coming in from the front wall would terminate in the rear of the room close to the back wall and the one coming in from the back wall would terminate in the front of the room near the front wall. This would create two 6" holes which, when seated, facing the screen, they would be the top left corner of the front wall and the rear top left corner of the back wall, but both holes/duct work would be covered up with a soffit built after the ceiling is built. Building them this way would allow the duct runs to be very long and both would be run in the same soffit. This way there wouldn't have to be any penetrations in the ceiling at all. Is this advisable? If I do it this way, other than wrapping the 6" insulated flex duct with more insulation, is any other prep work necessary or is there a better way to run the ductwork? No matter what I do there has to be two 6" penetrations "somewhere" and although I've researched this and thought about this a lot, I just cannot grasp how (even with this plan) my soundproofing attempts won't all be negated by bringing the ductwork in, no matter where I bring it in or run it. What do you think of this plan? SEE VIDEO FOR CLARIFICATION PLEASE -
As shown on the floor plan, the front wall is only one wall and a double wall hasn't been planned. The current wall is about 12" in front of the poured concrete foundation wall, so do I need a 2nd (interior) front wall or is one ok and can I just build a second wall for the side walls and back wall since they aren't near the foundation?
What is the cheapest kind of caulking I can use (and how much do I need) for the ceiling to wall joints, bottom of drywall to floor, etc.? Can you recommend a certain make/model?
For dead vents, I see a 6-in PVC Pipe is used to go from the inner (theater side) wall through the double walls and into the dead vent. How far inside the dead vent should the PVC pipe protrude? In my area a 6-in 20' (smallest I see) PVC pipe is almost $100 with tax. Is there anything I can use as a substitute for PVC pipe that will work similarly such as steel round duct pipe which is only $4.00 for a two foot section? Can I not just use flex duct for everything?
I've been thinking about using steel studs for the interior walls because they will be flat, won't warp, and I believe they will be easier to work with and get perfectly straight walls. Is it better to use steel studs for interior walls, though? Can I expect better performance and TL/soundproofing with steel studs? Are there any downsides or reasons I shouldn't use steel studs?
This question is much better explained in the new video, too, but I'll try to ask it in writing as well. Whether I use wood or steel studs, how do I attach them and the drywall to the headers? Please see the video for a better explanation of this question because other than the HVAC ductwork and the soffit for it, this is my biggest and most important question, I believe. I'm really afraid of not understanding and getting this wrong again and it costing me a lot of money and time to fix if I don't do it right again as this is already the second time I'll be building these walls.
Basically, I'm still not sure how to work around the headers which are the demarc points for the width of the room right now and are exactly 20' apart. The existing side walls are built directly below the headers and aren't decoupled from them at all. The top plates for the walls are screwed to the bottom of the headers. (Headers are made out of 3 2x12's with a piece of ply sandwiched in between each layer and held up by metal posts every 12' or so.) So the existing walls are only 80" tall and the rest of the height up to the bottom of the floor joists is made up by the headers themselves. Is this ok for the interior wall? The exterior wall, too? I could use IB-3 clips to decouple one or both walls from the headers, but even if I do that the header itself would still be the actual wall from 80" on up to the floor joists. I could add drywall to the headers. I could add clips, channel, and drywall to the headers, and lose a few inches of width. Or should I lose all the space, making the room about 18' wide instead of 20' wide and just build the walls up to the ceiling (in front of the headers) after the ceiling is decoupled and fully installed so nothing touches the headers? What would you do? Have both walls "under" the headers, one wall under the header and one in front, losing about 6" of width on each side, or neither wall under the header, losing the max amount of width?
Again, this is a difficult thing to describe so please see the video which will show exactly what I mean and am asking. SEE VIDEO FOR CLARIFICATION PLEASE
I'll put the videos in the next post.