Speaker cables and their sonic influence.
A speaker cable is a wire. It has no components (well, some do have a box on the cable, like MIT), and no power source. So it is a passive element. A speaker cable roll is to pass the amplifier's output to the speakers 1:1.
Any cable that doesn't do that is actually attenuating that amp's output in some way. If you connect two (or more cables) between the same amp and speakers, and they sound different, all but one, or all do some damage by not passing that signal 100% to the speakers. Only that could explain the difference.
Capacitance (C) and inductance (L) even if there is some, its value is very small. The capacitance is in pF (10-9) and the inductance in uH (10-6). Such small value, in a circuit that the amp's output resistance is close to null, has no audible (more than +/-0.1dB) effect on FR.
In a sound system we have plenty of elements that do influence the end result. It starts with the speakers of choice, the room we place them in, the placement of the speakers in that room, and then the electronics. Why do I need more variables, like cables to modify our sound? Where did you go wrong with that list, ending up looking for a remedy with the cables, and also willing to pay for that?
As we gave up the EQ stuff, when each slide had its clear frequency and gain set, we are getting back an EQ (sought of) with no idea what it really does on the frequency band or at the level of attenuation to our sound. We just follow blind folded our ears or a sales guy say, without having the tiniest clue of where we were and what do we ended up with. Throwing a dice has fewer options!