how can a line cord affect frequency response ?

Unfortunately this has turned into a freshmen 101 philosophy discussion.

Can we please stay on topic? please, can we let the pure technical treatment of this question carry forth?

I am one engineer who does not try to reduce the world around me to equations and mechanistic operations.
But, in this case
I do think there is a technically legitimate answer... This topic is a matter of electrical interaction, nothing else, pure and simple.

This thread is another example of how we audiophiles talk about hearing subtle differences/shadings, sure they are important, but then we rant and rave about this and that being so and the "well if your system, ear, room, etc are not up to resolution " blah blah blah...with no real technical discussion based on facts. It happens and will continue to just be so.

Why such an unwillingness exists to tackle the problem they way it should be dealt with is just lazy.

It's really ok to talk objectively. Objective science and engineering are what brings forth the awesome equipment we love and your music will still sound great to your ears if you choose to bury yourself in the technical details.
It's a matter of choice.

MRT, I am delighted you enjoy my Subalpine attempts to humour. Admittedly, I'd enjoy a therapist very much, except for all accounts payable associated with the service. Last I checked my blood pressure was still nominal. no danger taking myself terribly seriously. . . afraid I never did in the past and likely never will in the future. Similarly, I seem to experience a hard time taking logical sophistry too seriously. I am terribly sorry you feel compelled to offer me a quick funeral service during a court debate. . . in some way though, I feel very honored by the challange, as I am definitely not a legal professional such as yourself, nor The Queen's language is even my mother tongue, nor it is my second language. Would it make you feel truly spiritually fulfilled to do so? Or perhaps you would prefer to reconsider, take a big breath, and try a more convivial, or mayhaps even serenely peripatetic look at the topic at hand and at this virtual community of disembodied souls.

Dpac996, I'd love to contribute to the objectivist explanations of the PC phenomenon. My only problem is that. . . I am just not at all qualified to do so, except for spotting the occasional attempts to pseudo-science, which, fortunately, I have not detected yet in this thread.

my apologies to all for criticizing others for taking audio matters too seriously, when i am guilty of this myself.

i will try to lighten up and limit the sophistry, but not completely.

trying not to be pedantic, maybe i am, if measurements are taken, and observations are confirmed, one can justifiably have confidence that an event that took place in the past, will take place again. but such confidence is not certainty. without certainty it is not knowledge. most decisions are made based upon confidence of consistency of events.

i recently spoke to a cable designer and he asserts that the metal, dielectric, dampening material, geometry, shielding or the lack thereof, connectors and the connection--solder or other, all affect the performance of a line cord.

i guess there is no definitive answer as to this question.