It was like a dark cave in the house. There was sheetrock and plaster dust everywhere ( and I mean everywhere).   We pulled down all of that nasty old Rock Wool insulation and reinsulated the entire ceiling with the best insulation we could fit in between the roof trusses.

We ran new wiring (for speakers and lights) while the ceilings were down, and eventually put up the new sheetrock on the ceilings and walls.  Wow!, that's much, much brighter now!