I live in a loft-style apartment. The interior walls (the walls that create the bedrooms) don't extend all the way up to the ceiling -- there's a two foot gap between the tops of the walls and the ceiling. So it's not soundproofed at in the least.

I'm thinking of getting some sort of soundproof, translucent panels of some sort of material that I can cut to size and then using that to extend the walls the rest of the way to the ceiling. Has anyone done this before? Any recommendations as to materials? I want it to be translucent (or transparent) because I don't want to make the rooms any darker.