You said:
"But now i know why my system is "good" because i had a comparison BEFORE and AFTER these embeddings controls installation WITH THE SAME GEAR...
Then thinking that our sound is "good" is not enough now for me generally speaking ... We must know why....Thinking that good gear will do is not enough...Because of the huge impact of electrical noise floor problem, vibrations, and acoustic..."
OK, I understand what you're saying, and I agree on the importance of maximizing the acoustic environment (although not all cohabitants may agree). And certainly, unless you are immortal with plenty of time to kill, understanding the underlying principles is absolutely important. But I don't see that as being responsive to the OP's question, as I read it. You appear to be addressing improvement of any given system, versus whether the sound is good and enjoyable as-is, which I take to be the original question.
As you say, you had a system that sounded good to you, so I assume you enjoyed it, if you enjoy music (which I take as a given). It seems to me you are saying more that you were not *satisfied* with the system, even though it sounded good, or at some point you became dissatisfied with it, so you're enjoyment declined. But again, I would say that's a different question.
You appear to be satisfied, once again, and again love your system. I'm at that point as well - I could improve my system, without doubt, but that would come at an expense (not just money) that is higher than it's worth to me. It's at the point now where I'm far more disappointed with quality of individual recordings than with any "fault" I find in my system performance.
And to forestall @cindyment, yeah I could likely make many of those poor recordings sound a bit better with DSP, but dynamically squashed recordings are never going to sound wonderful - except in the car!
Enjoy the music...