I'm currently in the process of building a new shop, and am fast approaching point where I need to choose a route to go for insulation. The new shop is about 15 feet from the neighbors house, and most of my shop time ends up being in the evenings, so having good soundproofing is important. I was originally planning on going with dense-packed cellulose, but an insulation contractor I spoke with said that blown in fiberglass provides better sound proofing and cellulose can have some settling issues. Anyone have any insights into which might be a better choice? In addition to the insulation, I'll be applying a double layer of 5/8 drywall on the neighbors side of the shop.