I pretty much agree with all in Manitunc's post. I'd also add from my experience in building separate dedicated HT and audio rooms in my previous home :
Avoid parallel surfaces. Stadium seating and/or cascaded drop ceiling panels at various heights from the floor will do the trick in the height dimension and having the room width somewhat narrower behind the speakers than behind the listener will work in the length dimension. A gentle arc in the "front and back" walls will address the width dimension.
To maintain visual appeal, I created a wainscot with wood veneer to panel the first three feet of the side walls, the installed a strip of contrasting molding to form a "beltline" over the wainscoting. Above that, I lined the walls with acoustically absorbtive panels up to the ceiling and covered that with decorative (think speaker grill cloth) material. It looked great and was very effective for killing reflections above 150ish hz. (My speakers and subs were in-wall in the HT room and that helped in the true bass.)
Finally, in my 2 channel room, I had the happy accident of finding a 4' concrete caisson toward one end of the room. I had the contractor fir a wall around it and build a rack into the nook that was created. Four feet of concrete caisson turns out to be quite effective in isolating a turntable from airborne vibration. You will likely go a different way, but isolating the source components from the listening area is a good idea.
Good luck with the project and I'm sure you'll dig the results.
Marty
Avoid parallel surfaces. Stadium seating and/or cascaded drop ceiling panels at various heights from the floor will do the trick in the height dimension and having the room width somewhat narrower behind the speakers than behind the listener will work in the length dimension. A gentle arc in the "front and back" walls will address the width dimension.
To maintain visual appeal, I created a wainscot with wood veneer to panel the first three feet of the side walls, the installed a strip of contrasting molding to form a "beltline" over the wainscoting. Above that, I lined the walls with acoustically absorbtive panels up to the ceiling and covered that with decorative (think speaker grill cloth) material. It looked great and was very effective for killing reflections above 150ish hz. (My speakers and subs were in-wall in the HT room and that helped in the true bass.)
Finally, in my 2 channel room, I had the happy accident of finding a 4' concrete caisson toward one end of the room. I had the contractor fir a wall around it and build a rack into the nook that was created. Four feet of concrete caisson turns out to be quite effective in isolating a turntable from airborne vibration. You will likely go a different way, but isolating the source components from the listening area is a good idea.
Good luck with the project and I'm sure you'll dig the results.
Marty