How do you know if a cable is neutral?

Bigtee has given a very good answer. I discovered that what I had thought was neutral wasn't really, when I heard a _really_ neutral system.

The gentleman who had put that one together had immensely more experience than I did, as a hobbyist, reviewer, retailer and distributor on two sides of the globe. To him, the term "neutral" meant the sound of specific equipment in specific combinations, as did "warm", "cool", "analytical", "musical" and more. From his collection, he could pull out pieces that demonstrated each quality. I was just floored.

He educated me so that I could tell him what I liked, and once I knew, it didn't matter to him what my preference was. One sound wasn't "better" than another, just different in quality. The notion that "it's a matter of personal taste" didn't just serve to make distinctions meaningless. After those sessions, I could name my own taste and know what it meant, and I never again thought it was better than anyone else's. That's what an education does for you, I guess. I've never stopped being grateful.

Thanks for the chance to share.

Yeah, what Bigtee said. Very cogent and accurate response to a great question! At the end of the day, there's only one (or two if your partner is also into it) opinion that matters: yours. Neutral becomes the reality you seek.

Cables all do something to the transfer of information. If what they do is not something our minds can convert into harmonically acceptable information, then it sounds inferior to a cord that only deals with information which can be acceptable in the real world. Aftermarket cords either smooth out the sound or make it richer. Generic cords add non-harmonic info that any critical listener finds to be 'wrong'....because it just doesn't fit.
The harmonic series fo any note is the fundamental, octave, third etc.....if you add something outside of that pattern it wont fit.

Guess what... It's all relative!

I could have asked another way; Can we ever know if a cable is neutral?