Stereo you state:
Try some known good recordings...ask for suggestions if you need!
My music taste is old Genesis (pre 1977), Gentle Giant, Yes etc. (head music)Some of the R&R mixes from this period SUCKED...maybe that's could be a factor. The problem exists on the original master tapes. I have Leon Russell's CARNEY on a DCC Gold CD [re-mastered by Steve Hoffman] The big hit "Tight Rope" was severely compressed; all of the other songs sound entirely different. Record labels would purposely compress songs on many albums if they intended to possibly release them as singles. Made them sound louder on cheap ass FM car stereos of the day [similar to Phil Spector's "wall Of Sound"...which sounds hideous on any decent stereo].
Try some known good recordings...ask for suggestions if you need!