Plaster Walls

Sheetrock is unknown in Germany , Plaster is.
Every room I ever had in Germany was better than any American one I ever had.
Outer walls being 2-3 feet thick might have had something to do with it as well.

Thanks for all of the tips. Sounds like it won't be as much of a problem as first thought. Have started putting in drapes and will proceed from there with the panels and softer furniture.

There is a guy named Michael Green that runs a board called Tuneland. He seems to have a vastly different philosophy concerning room acoustics. He said Sheetrock is good while plaster is bad. He seems to believe equipment needs to be "tuned" and then put into an environment which does have highly resonant properties. At least that is what I can gather. Sounds like his goal is to create a sound that is perhaps bright vs. neutral.