We're trying to create a quiet office space. The shared wall is paper thin and noise (including phone calls, conversations, music and tv) sounds like they're in the same room. We do NOT want to tear out the walls and add insulation then put the drywall up again. Have you had any good experiences? We're researching blow in expanding foam insulation, attaching fabric covered panels on the shared wall, hanging fabric along the wall (it's sold, and looks like a large quilted piece of white fabric). Any good or bad experiences you've had appreciated.