Doesn't sound like an upmix. I am surprised, it is a proper 5.1 mix with proper separation et spatialisation (although the equivalent of side 1 of disc 1 is sounding pretty bad).
Retirement followed quickly the death of his son, and maybe, it was the blow that precipitated that retirement. I was not interested by albums post Discovery, save Amarok, damn it, I waited.
I was aware of Ziggy (a BR I have also), of Heathen (ditto), not of the others. I am going to look for them if they exist in physical form. Thanks.
