Tbh the biggest difference in cables I hear is what I would like to call signal drag. Seems to be caused by the insulator choice causing parasitic capacitance and releasing the energy slowly. Stock fiio cables are pretty bad in that reguard and even the stock FD7 silver cable has this warm background and particularly high noisefloor for my taste.I have a really simple answer to that question.
It simply comes from being in contact (with no prior communication) on the results of a cable. Meaning another listener with the exact same IEM perceived the same qualities in a different part of the world, without prior knowledge of your experience.
And you may wonder just how far the tiny details are in common? They are very involved and have to do with soundstage, midrange and vocal tone, and bass texture......amongst other things, I could go on.
So for the people into cables, often we are all experiencing the exact same effects. Even retailers will include a bass recessive cable like the ISN SC4 as an aftermarket cable at near $100 (extra) to try and align an IEM tone.
Cables have character and are freely talked about among enthusiasts, due to their performance enhancements. Literally every IEM made today has thought put into just what would be the best cable to dial in the sound with-in the perspective budget parameters.
With reguards to the Silver vs copper, Ive found the cleanest UPOFC copper while nice can strip all rythem and pace to the music in addition to being too bright in the upper mids. While with Silver it has the potential to be completely weightless and dead sounding yet harsh. What Im saying is that there is no point chasing the best cables if the driver wasnt tuned with those in mind.