Raddle, please listen. Accuracy of the signal is not subjective. A subjective person's perception of whether something is accurate is subjective. The two are not the same. Moreover when you talk that one person is interested in timbre, and another is in something else, yes that is subjective. And yes, the perception of those different qualities are subjective. But you are down to preferences and experiences. And one can tune a system more toward one than the other. But that works best if there is a baseline of accuracy for reference. And preference is never going to be a transferable bottom line measure of overall accuracy. If you don't get the two separate in your mind, you are never going to make sense to others or even yourself in the end.