I guess I approach it from science background that makes it hard to believe in audio memory lasting 200 hours- especially for slight changes (10%). But as they say YMMV! I think my audio memory falls in the average range. A big change? Bad to Good? I can believe that. Unless you measured it before and after?
For some it seems that "audio memory" is the gold standard for determining if something has changed.
There is however, another way to approach this.
When playing a familiar track and you hear, not just a slight shift or new subtle nuance, but a whole nuther level of the performance, and it is blatantly obvious, THEN "audio memory" takes a back seat.
As to measuring these sorts of changes, well, thus far I have not found any measurement that corresponds to, or can be directly linked to, these kinds of changes.
How can anyone and by what technique can you measure when the harmonic structure of an instrument becomes more 'real' when all you do is change a fuse or a power cable?
And by 'real' I mean it is blatantly obvious that the instrument being presented has more harmonic content and at the same time it becomes more cohesive and coherent.
That some don't experience these sorts of changes seems all to evident.
That doesn't mean these changes don't happen nor that they are necessarily the result of confirmation bias nor a host of other rationalizations.
And it would appear that some simply can't or certainly don't hear these sorts of changes, at all, no matter what.
But I suspect that those who simply can't hear these sorts of changes aren't into tunes as 'serious' hobby in the first place.
Or they reach nirvana much much sooner than those of us who are addicted to chasing 'better'.
Additonally the requirement for 'proof' is along the lines of the logical proposition that you can't prove a negative.
Meaning just because something isn't noticed, doesn't mean it can't be noticed, perhaps by someone else, in another context or circumstance etc.
It's also pertinant to note that the 3rd 'step' in the 'scientific method' is observation, which follows the step of devise an 'apparatus' with which to make observations.
Our playback systems are the 'apparatus' and our observations are in part based upon how well it serves our purpose at making observations.
And the next step is to then formulate theories and the like from the observations and subsequently refine and incorporate further observations into the theory that better reflect the observations themselves.
This is a form of feedback loop.
But observations are absolutely essential in this process, and so to arbitrarily dismiss observations because they don't match ones own experience, merely means the first 3 steps (1. propose a question, 2. devise an appartus to explore the question, 3. make observations) doesn't match up with others processes of evaluation.
And not that the observations are
necessarily fraught with errors or are the results of wishful thinking, confirmation biases, or the like.
JJ
ps Note: This post isn't aimed at Exacoustatowner, but rather is a general collection of thoughts to ponder, or not.