I am going to be creating my first soundproof door assembly. I have my idea down for the frame and door itself, but the problem is going to be that empty space between the door assembly and framing of the wall.
A few ideas I've had:
- Get some MLV (mass-loaded vinyl) and backer rods. Wrap the backer rods with MLV and stuff them into the cavity. The rod will allow for compression which would give a tight fit.
- Sand. This may sound insane, but I figure I could create a custom casing that I could slide into the cavity, after which I would pour sand into it from the top. The casing would eventually fill up and expand to fill the cavity. The only thing I might have to worry about is settling which would require it to be refilled a bit at the top, but perhaps there's a type of heavy sand that wouldn't settle.
- Green Glue. Using my MLV/backer rod method, an idea came to me to create an actual sheet of Green Glue which would serve the purpose of the MLV. Basically, I would get some heavy-duty plastic, spread GG liberally out all over it, then put another layer of plastic over the top. If I gage the thickness with something that's about 1/8" like some thin dowel rods running along the length of the inside and then setting something heavy on top to flatten it out and disperse the glue, I think I can get a consistently level sheet of GG compound. GG thickens up after a few days, so I wouldn't have to worry too much about any of it squishing out all over the place.
- Safe 'n Sound insulation stuffed liberally into cavity.
Since my door is going to consist of a layer of plywood, GG, cement board, GG, and plywood all in that order, I am sure it's going to have a fairly high STC. Therefore, I'd like to make sure I get the edges around the door really well even if it means the edge has an aburdly high STC in comparison to the wall and door assembly themselves.