“All cables are equal, but some cables are more equal than others.”
Actually they aren’t. Some cables, often “high end” ones do audibly color the sound.
“In that case, how do you know if the cables are either transparent or color the sound?”
Fair question. One can look at the multitude of controlled listening tests that demonstrate it. One can look at bull tests and see or literally hear it. One can do their own controlled tests if they like. I have done a few of them. Some of which would have revealed *any* audible differences were there any to be heard.