What's an efficient way to soundproof the space between my door frame and wall frame?

Question

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.

Answer 1

Noiseproofing, as you know, is best assisted by decoupling dense masses.

I am going to presume that your walls are framed thicker than standard 2x4 (as staggered 6 is a very common technique)

In this case, you have a pretty wide cap to fill in the shimmed jamb.

I would shove fiberglass into the cavity, or spray in foam, making sure not to overfill!

Then I would lay in greenglue (or their gap-filling material), then I would lay in the backer rod. Finally, one more application of the gap-filling material before setting the casing.

Here is a video of a door company demonstrating the install: http://www.acousticalsurfaces.com/acoustic_doors/soundproof_doors.htm

Answer 2

I used to work at one of the large hardware chain stores, and we would recommend to people to stuff an ample amount of R-11 or R-13 fiberglass insulation in there. If you've got more space, you could look at using strips of fiber board, (or concrete expansion strips), or specially designed sound-board (also available from most large hardware stores).