bmoc wrote:I got it from here.
https://www.amazon.com/gp/product/B017DVK1IE/I purchased two 25ft rolls so about $400 for me. It was way cheaper than using insulation made for soundproofing like Roxul Safe N Sound. It is a beast to install though. If I had it to do over again, I would have had two people with good upper body strength assist me. Two people to hold it up and one person to nail it in.
Don't even think about installing this stuff yourself unless you can get your hands on a roofing nailgun. Trying to nail it in by hand or with screws will kill your arms (and the arms of whoever is holding it up). On a related note, it is hard to find small quantities of coiled roofing nails at Home Depot. I got the smallest box they had and I probably have about 6000 leftover nails.

I looked into lots of soundproofing options: Safe N Sound insulation, Green Glue + an extra layer of drywall, mass loaded vinyl, and resilient channel. I figured regular R-13 insulation and mass loaded vinyl would give me the best bang for my buck. I wasn't looking for total soundproofing; I just wanted enough so that normal volumes would not keep my daughter up at night. If I were trying to soundproof an existing wall or ceiling, I'd probably go with Green Glue and an extra layer of 5/8 inch drywall.
Just saw this now. I don't know if you are aware (I posted a thread) but I used Green Glue some years back for a wall between two bedrooms. The rooms were pre-existing with 1/2" drywall on either side and fiberglass insulation between them. I used 2 tubes of Green Glue per 4x8' sheet of drywall (you can use 3 per sheet for increased blocking of lower frequencies). I only added the Green Glue and a second layer of drywall to one side of the wall, and I only used 1/2" drywall for the second layer. Although I did add paneling on top of that, which is another 1/8", which would total 5/8" for the second layer. I followed the directions for the Green Glue explicitly, and I even used their "sealant" around the perimeter of the wall.
I was very pleased with the results. If you are speaking at a normal volume, it is extremely muffled on the other side of the wall. Extremely muffled meaning you cannot make out words but just barely a noise. My TV at medium volume, and mind you I have a 5.1 system and never use the TV's speakers, is very muffled through the wall. At low volume it can barely be heard at all.
Anyway, just wanted to give you some feedback in case you ever consider using it in the future.
bmoc wrote:They finished installing the drywall about two weeks ago and we have been painting ever since. Last night I put the final coat on the basement.
Nice! It's exciting at this stage when it all starts to come together.