[BIslander]

Have you calibrated by hand with a test disc and an SPL meter? That's a good idea, even when using an auto-configuration system.

You can always increase the volume of the center channel a few dBs. The center carries most of the dialog.

Or, you can engage Dynamic Range Control, although that usually only works with Dolby sources. Your receiver may have a "midnight mode" that works like DRC on all sources. DRC lowers the volume of the loudest parts and increases the volume of the quietest parts, which makes dialog easier to hear through the other sound effects.