Peter, I would like to do the test too, but I already threw 7 out.
Maybe I'll have to go back to get more happy?
What I think happened here was a change in sound during one album on Win8. I played for my children a K3-album (

) and they are happy to jump around. But the first track already sounded weird. A lot of bass but like it was mixed with glue and could not get loose. Mid's sound recessed, highs not airy.
But since the kids didn't complain I left it on.
But a couple of songs later the sound became more normal.
I thought maybe it's warmup of the amps or me getting used to it.
But then it shouldn't be a 'new' experience. And I heard it the first time I tried Win 8 and thought I got rid of it when I changed to your settings.
After reading your distortion story I felt I could write this without making a fool of myself!