@yoyoyaya earnest question for you.
You said,
the point is that one is aiming to retrieve the information which is already there and not to add information which is not present in the recording.
Original recordings vary a lot (as you know). When an original recording was something made for car radios or some other mass listening application, they sometimes exhibit qualities which, on a good stereo, sound bad. When audiophiles seeks ways of dealing with that -- say with a tube DAC or EQ or certain cables, etc. -- are they trying to remove information in the original recording in order to make it sound better?
I really don’t know the answer to this, so I would appreciate anyone with experience explaining what is happening to the "information" in the original recording when we try to make it sound better.
Also, consider this analogy: when we take raw steak and cook it and add garlic salt, are we obscuring or reducing the original flavor information in the meat?
You see the analogy I’m trying to make, but perhaps it is not a good analogy? Feel free to attack it!