In reply to:

The one area I am not yet happy with is the clarity of speech (center speaker) when there is a quiet scene (whispers or soft spoken words). If I turn up the volume to hear these parts, any subsequent action scene is too loud.

I used the auto set-up feature of the Pioneer, and then created a custom configuration where I varied the level and frequency equalization of the speakers, but I am not getting the clarity I want - the center channel sounds slightly "hollow" (echo?) on the quiet scenes. There are so many variables and permutatuions that I cannot be sure what helps. Also, I tried setting the DRC (Dynamic Range Control) to different settings, but still no magic.

What do you have in the way of acoustical room treatments? You may be experiencing a null in the specific frequency that sounds hollow for that particular seating location. I suspect there is only so much the receiver can do and can not address very specific acoustic room problems.