A great sounding room is a huge head start. Good sounding rooms are more than just good sounding for the stereo system. They’re pleasant rooms to be in, to talk in, to sing or play an instrument in. That’s the good news. A properly treated room just sounds nice all around, for all uses.
If you have a room that’s edgy sounding to talk in, you can hear your foot steps cavernously echoing off the walls and ceiling, how much better can you possibly expect the stereo to sound? This kind of sound can occur in well furnished rooms that have high ceilings because there can be a lot of bare wall space above the furnishing zone.
The bass is one area that might go unnoticed in daily activity because you are not necessarily making bass sounds that appear in music. I think that’s why bass treatments and equalization can still be necessary for a stereo system in an otherwise very nice sounding room that’s simply been treated with furnishings.
Another issue is symmetry and stereo imaging. The 2 speaker arrangement is a fragile thing in terms of imaging. Some strategically placed treatments on top of the standard furnishings can go a long ways to improve imaging. An imaging treatment can be as simple as an angled flat surface. I've got one of those in my office right now because there's a wall close to my right and not to my left. a 2' x 2' angled flat wooden panel centers the imaging for me.
