I built a 4x8 room to practice my guitar in in the corner of a basment. Two walls are exterior cinderblock. The other two are 2x4 studs with 3/4 fire rock on each side with R-13 insulation in the middle. I added two layers of the 3/4 rock and a 2" layer to pink foam insulation between them. On top of that I've added a bunch of moving blankets attached to the walls inside. One wall is a 4x8 swinging door that has an interior and exterior layer of 2inch pink foam insulation.
It's pretty quiet but I'm wanting more. Should I coat teh interior walls and ceiling with MLV and then rehang the moving blankets? I can't pull the drywall and wish I would have put it in then. Any other ideas for further db reductions. I have a large tube amp and want to crank it. I can now turn it up but want it louder.