Subjectively:
When you forget sound and discover NEW music because the acoustic is so good that you can hear old albums in a new way and new album at the limit of your musical frontiers at their optimal acoustic rendition...
Objectively:
1 step in my audio life:
my audio system was not well embedded mechanically, electrically and acoustically, and my gear was average consumer gear (stereo furniture system of the 1960); then ALL my albums sound almost alike one another... 13 years old my first stereo system...All albums are so mediocer acoustically that even the notion of good and bad recordings is not important... Anyway at 13 years old i was listening music not sound...
Second step:
Almost all my audio life for 50 years i bought very good gear but it was never well embedded mechanically, electrically and acoustically, then all my albums sounded different in 3 categories: badly recorded , very goodly recorded , AND between these 2 categories the " mediocre" category for the most majority of albums...The quantity of the "not so good recorded" or "mediocre" category exceed the few good one and the few very bad one...The diffference between first step and second step is the ability gained with a better systen to discriminate very bad recording from very good well recorded one....
last and third step :
I only reach this FINAL step for the last year; BECAUSE i succeeded in using rightfully the CONTROLS for the 3 embeddings working dimensions , mechanical, electrical and acoustical with exactly the same basic gear i already owned in the last step.... And NOW well embedded and well controlled in all his working dimensions, mechanical, electrical and acoustical, all my albums are no more in ONLY three categories...
They are ALL interesting now, even the bad recorded one are interesting WHY ?
Because i could and will hear MOST acoustic cues worked by the engineer of each recording album , then ALL album are interesting now and because of that i listen music through them and i am no more tempted to discard them because they are not all so well recorded...
Dont upgrade anything BEFORE embedding it well in his 3 working dimensions to begin with...