you would think that if there was a difference you could hear it within a minute or so unless it takes you time to convince yourself?
Imagine you are looking at a Renoir painting, and then comparing it to a really, really good forgery of the same painting. When you look at the forgery at first, you can't necessarily tell that it is not an identical copy. It may take you more than a little while to figure out which is real and which is the forgery. If you just glance back and forth from one to the other, you may not see an obvious difference. But over time, as you study them closely, you will notice the brush strokes on one aren't as perfectly placed, that the pigments in the paint are not as colorful or as deftly mixed, etc. You get the idea.
If someone secretly replaced your beloved painting with this forgery, you may not notice for weeks or months or ever. But someone with a keen eye, who knows what to look for, who is well-trained to spot of forgery, could tell the difference pretty quickly. But they wouldn't do so through switching back and forth quickly glancing at one then the other. They would take time to study each painting intently. Why would anyone think music is any less complex than visual art?
To someone who isn't well-trained, who doesn't truly understand and appreciate art, and who has convinced themselves that its all pretty much the same, the forgery is completely satisfactory and a bargain at its price point. But to someone who has an eye for art and the training to go along with it, the forgery is simply horrid and the original is well worth the money invested.
Likewise, if you don't have an ear for the nuances of music, or a system and room capable of reproducing those nuances, then zip cord is probably fine for all your cable needs. If you have a high end system, a well-treated room, and a well-trained ear, then you will probably hear the benefit in better cables. Like all things in high end, there is plenty of snake oil to be found in the cable industry. But there are also definite differences in the quality of cables, like everything else, and they do make a difference depending on the setup they are placed in.
But these arguments about "all wire is the same" and "the only way to tell a difference is from A/B testing and if you can't tell a difference with that then there isn't one" are usually put forth by engineers with a tin ear and no music background whatsoever.
the only time I can even remotely believe that cables make a difference is from a cartridge to a pre-amp as the signal is so ridiculously tiny and is amplified so many times from that small fragile state that perhaps interference could happen.
