bagwell359
Headphoneus Supremus
Sorry, guys. I have a degree in one of the sciences. Cables DO matter but it's all about electrical resistance and good electrical contact. Higher frequencies are transmitted near the outer surface of a conductor. That's why not so good conductors are often plated with better conductors. It's cheaper but the effect is the same as making the hole wire of a better conductor. Silver is only marginally better conductor than copper but it oxidizes less. I would choose silver over copper anyway.
There are two other factors besides resistance that need to be considered.
But I have found that HFM stock cables (HE-500, HEX v2, and HE6se) all suck, and standard aftermarket (and probably standard DIY cables) mascerate them - 2 of 3 cases tested AB. Be still I know you won't rock your beliefs on my word.
I spent the years from 1995-2017 not being interested/caring in differences between cables (although earlier I had experienced a few cases of AB tested differences).
But a bigger issue with headphones is source impedance and load impedance. In practice that means an OTL amp should be running HD-600's, Beyers, etc. And low impedance planars under 60 ohms or so, should be run by SS and a handful of hybrid amps with low source impedance. Cables used in a mismatch situation are not likely to sound good.