I suspect that if I hear a difference people here will belive me. If I don't hear a difference people will assume that my system is bad or my hearing is bad or that after 6 ft of cheap line cord it can't get any worse.
Which brings up a question. Just how low does the distorion of ones system have to be before it becomes possible to hear the additional problems caused by cheap line cords.
And, science is what makes the marvelous equipment we have possible. Scientists and engineers understand and design amplifiers, preamps, digital and analogy recording and play back technology. Non-scientists make line cords and speaker wire and can't explain how even they work.