I'll second Ernie on this type of isolation tweak. I installed the electronics for the living room setup in the hall closet. Very little air born vibration and a lot less coming up from the floor. Also when the lights are out and the music is on, no glowing LED's or tubes to distract me from the music. Another bonus is that I can suspend and organize the cords and cables for the best sound as they are not in plain site.
Best tweak
Sometimes the simpleist tweaks are the best ! The best one I've tried lately is to use some rubber door stops to tilt the center speaker down from the top of the monitor towards thr listeners' head. What are some others that have worked for you ?