Well, goodness, I've had scope traces & FFT's for years that showed
differences between two particular cables I tried. Now, it's true that I
used cables of the same physical length (10'), rather than same
resistance; so one is 100 m-ohms and the other is 130. I think one can
make an argument for doing it either way; and I'd be happy----sometime,
when I have the time---to re-do it so the R is the same. The difference
I heard was easily measurable too. The cables' FFT curves separated at
about 12kHz and one was -1 dB rel. to the other at 25kHz. That's as I
remember it; I did this a long time ago. The response I measured was
from power amp input to speaker terminals, so the absolute response is
that of amp+cable, which of course does not affect the issue. The amp
was a Dyna St70, the speaker an LS3/5A. This combination was at the time
a very popular one, and I happened to have these items in my lab. The
only thing I know of that one might want to do another way is to make
the lengths unequal so that the R's will be equal; on the other hand, in
practical use, that's not what one would do.

As a separate matter, I do wonder why you're obsessing about this issue,
though, if you'll pardon me for saying so. Putting the same energy into
making recordings--or better yet, making music in a chorus; there are
choruses for everyone--would surely be more satisfying.

James Boyk