Is this the spectrum between the tubes and solid state: on one side is "neutral" and on the other side is "tubey"? Or is one end of the spectrum "analytical" and then "neutral" in the middle and "tubey" on the the other end?
I’m also curious how people define "neutral." With modern multitracked recording (w/ overdubs, reverb, panning, tonal choices, etc.) what is neutral? Here, I think of prepared dishes; take lasagna as an example. Is there a "neutral" lasagna? It would seem there are many recipes and many possibilities. If you serve me a hamburger, we’ll have a real problem -- but it will be a category mistake, not a problem with non-neutrality. Plus, since so much music is compressed -- mixed to be heard over non-audiophile gear -- how could a piece of audiophile gear seek to "get back" to "real music"? It's all a concoction, and one largely prepared for non-audiophiles.
With acoustic instruments, "neutral" makes more sense; there’s some degree of reality which can be appealed to; if a clarinet sounds like an alto sax, then there’s something not being reproduced faithfully. But beyond that, a clarinet can be played in different ways, in different halls, etc.
I see the word "neutral" being used to celebrate solid state amps; and for those folks, "tubey" is a put-down. (And we see that those terms "solid state" and "tubes" are largely placeholders for certain aesthetic preferences in sonic presentation.) But what’s really at issue here seems non-resolvable from the start; solid state amps (so to speak) present sound in one way, "tube amps" in a different way. Each presents something *as* music, and then each of us decides if we enjoy it. If not, get something else, roll a tube, pour a beer, etc.