"Quite what it is that wrought these improvements I do not know."
Believing they would be better before you listened to them?
Please... He's an audiophile=he knows what he's talking about.
His website includes many useful tips.
In Tuning Tip #3 we read:
"Before connecting any cable to your system, give it a firm, robust shake. Grab hold of one end of the lead and shake it for a couple of minutes before you connect it to your system.
The process must – I suppose – do something to the molecular structure of the conductors, dielectric or insulation. What that is I do not know, nor do I care, but it has worked many times in my system."
Quark-shaker; if you try really hard you may turn it into gold, changing molecular properties of the cable. Shake it!
Aha! That's the solution for when we read on this forum about poorly mixed/mastered CDs/CDRs. They just need a good shake, then they'll sound fine.