Wow, that sounds really strange. I'm sure somebody already gave you the hint to disable the audio enhancements for your realtek playback speaker device?
Got it in one!
I completely forgot about that setting, since I don't have it on my primary laptop. Well, former primary laptop.
That took care of the issue, and all it cost was a 10DB loss of maximum volume which enhancements seems to provide.
Thanks Ralf, and to others who offered help; and blessings for 2020 to all on this list!
