It's Simple

I am fine admitting that I am no expert. But I have develped a theory of a sound system, which I describe as the “limiting variable” theory. It works for me. In my limited experience, my system will usually sound only as good as the quality of one or two limiting variables - the amp, pre-amp, speakers, the cables, the source, etc. When I introduce a new variable, it usually makes a difference, sometimes good, sometimes not, but very rarely none at all. If it makes a positive difference overall, then I move to the next limiting variable and change or tweek that component, cable, etc. If it makes no difference, I conclude that the limiting variable lies elsewhere. It is not scientific, but it works for me quite well. Sometimes my system hits a plateau, and it just wont improve with what I have. That is when I know that I must move up in overall quality for everything. But, even then, I usually start with one variable - significantly better speakers, for example, and start the process over again. There is not a perfect correllation between the cost of a component, cable, etc. and whether it is or is not a limiting variable. Some bits just sound better with other bits. But, when a bit makes a strong, positive difference, I conclude that its predecessor was likely a limiting variable.

I guess that is a long-winded way of saying that the higher quality my system is, the more a simple thing like a cable improves things, or the opposite. For my system and ears, I have found that to be a consistent reality.

@yping 

such as IMD, etc

Distortions like TH, IM, TIM are active components faults.

There are numerous other cable properties: Proximity Effect, Skin Effect, Purity, Metal, Plating, Insulation Dielectric, Fatigue, etc. All these properties have an effect, but well below LRC.

For all intents and purposes, cable R can be ignored as it is a minor fraction of speaker R. Longer runs, say 25 feet or 30 feet, cable R can equal amplifier R, cutting Damping Factor in half. Additional length also increases L & C, which can cause stability problems.

Cables should be as short as reasonably possible, of the same length and as straight as possible [Bends increase L, but this is more theoretical than practical].

In general, the more current, the shorter the wire should be. Therefore, amps should be as close as possible to the speaker with long inter-connects from the low level electronics.

Got it backwards ieales!