The dummy got a brain!
When I noticed the left channel, right channel disparity, it was over two years ago. First I corrected it by simply turning the left volume higher. Not satisfied with that, I went through a year of trouble shooting to find nothing wrong, but I still had the same problem.
After discussing it on this thread, it became apparent that it was room acoustics, and the solution must be to install sound absorbing panels on the right side of the room.
Just an hour ago, while I was trying to verify the cause of the problem, I removed the drapes from the patio door that make up the left side of the room; perfect balance. Why didn't I see that before? Although that's perfect balance, it's too hard, and I still have to install a panel on the right side of the room, because who wants to be exposed at night.
My point is, all I had to do in the beginning, was to remove the drapes in order to verify the problem and the solution.
Enjoy the music.