Surprised no one yet has invoked the presence of different harmonics, at different percentages in different ratios. As @newbee says, it's at least partly a product of variations at certain points in the frequency range, but the relative presence/absence of harmonics is part of it too.
What does 'cold' mean? What does 'warm' mean?
Aside from the 8 year old 'hey go open a window' replies; explain a 'cold' sounding cable? A 'warm' sounding amp?
Moreover: do we all assume these are terms we universally nod our heads to in agreement, whatever they are?
Moreover: do we all assume these are terms we universally nod our heads to in agreement, whatever they are?