I'm renting a condo where the master bedroom is a loft with a large opening overlooking the living room. The staircase up there also doesn't have a door. For noise reasons (my roommates stay up very late) I'd like to plug up the hole with something as sound-proof as possible, and get some kind of door in the stairs. I custom fit some pieces of insulation in the window and have a curtain in the stairs for heat purposes, and while they provide privacy, they block zero noise. Any option needs to be completely removable when I move out with no permanent damage. Thanks ahead of time for any suggestions.