You really don't know. Each system the cable is inserted in will interact differently with a different possible result.
I have often wondered how you actually tell also. You would have to have a known absolute to compare it to which I don't think exists. One mans neutral is another mans colored.
Most of the time, the reviewer is comparing it to something HE has perceived as neutral in comparison to what he has gained through experience compared to HIS reference. Now, wether or not it really is neutral---can't say. Depends on HIS reference and tastes. Look how many reviewers use the same cable---hardly any! watch how many responses you get to a thread on cables with each person's "Neutral" recommendation.
I can say that a cable can only degrade the signal, it can't make it better. The cable that degrades less of the signal would be more neutral. Most people just go with the cable that seems to offer more of the attributes THEY like and label it neutral! Hell of a good question!
I have often wondered how you actually tell also. You would have to have a known absolute to compare it to which I don't think exists. One mans neutral is another mans colored.
Most of the time, the reviewer is comparing it to something HE has perceived as neutral in comparison to what he has gained through experience compared to HIS reference. Now, wether or not it really is neutral---can't say. Depends on HIS reference and tastes. Look how many reviewers use the same cable---hardly any! watch how many responses you get to a thread on cables with each person's "Neutral" recommendation.
I can say that a cable can only degrade the signal, it can't make it better. The cable that degrades less of the signal would be more neutral. Most people just go with the cable that seems to offer more of the attributes THEY like and label it neutral! Hell of a good question!