Neutrality is a complete fiction. Most who subscribe to the concept make a subjective judgment that component A sounds more like the source than component B. Well, our hearing all differs, our systems all differ, and very few of us ever get to hear the source. And if we do get to hear it how can decide what in the long chain from recording studio to speaker is corrupting the signal and by how much?
I find the word used most by insecure audiophile types trying to justify their purchasing decisions.
Now you could attempt some objective, measured, definition of neutrality. But I find that one tough as well. Take two amps, both measure exactly the same but one has 1% second harmonic distortion and the other has .3% 9th harmonic distortion. Well the first should be considered more accurate. But wait a minute, the work of Jean Hiraga and others has repeatedly shown that the ear finds higher order, and odd order, distortion much more jarring to the ear. So the first amp may measure more accurately, but the subjective opinion might be that the second is subjectively more accurate as it does less violence to the fabric of the music.
