With respect to the first question, my experience mirrors that of the OP, and John (Jmcgrogan2), and Minorl. I have a not inconsiderable number of poor recordings that I would prefer to listen to via YouTube on my $90 computer speakers rather than on my main system. But as my system has evolved, the great recordings continue to sound ever more realistic and more pleasing.
Regarding the second question, John and Russ (Rcprince) make excellent points. In my own case, though, I have not noticed a great deal of sonic variation from day to day or time to time. Perhaps it is not entirely coincidental that there is no industry and very little commercial development in my area, and presumably the quality of my AC is therefore relatively good and relatively constant.
Regards,
-- Al
Regarding the second question, John and Russ (Rcprince) make excellent points. In my own case, though, I have not noticed a great deal of sonic variation from day to day or time to time. Perhaps it is not entirely coincidental that there is no industry and very little commercial development in my area, and presumably the quality of my AC is therefore relatively good and relatively constant.
Regards,
-- Al