I built a special add on in the upstairs main room of our house. I added as much insulation as one could stuff in there. Still it's not enough. I wish I had made the walls double thick and off set the studs. I still border a wall that's up against the attic. That brings in a lot of street noise...ie.Loud stereos and such. I'm going to have to go into the attic space and put more up against the studio wall soon.
Yeah Ben, double walls is really the only way to go. You've got to have that airspace to keep the sound out.
I'm lucky enough to be in the middle of 8 acres, so road noise and neighbors mowing are never a problem.
The Whisperroom takes care of any noise from our animals.