"It is important to mark the source end of the cable with marker or tape (or note direction of the writing on the cable) on the cable as the run in time/process makes the cable directional ( i.e. better sounding in one direction only)". "I for example could provide plenty of scientific theory to support my claims but on the other hand - from those who repute our claim - all we get is very little substance other than it's all in your head mate and its is all nonsense. Some people don't seem to realise that it is not the copper conductor etc. that requires burn/run in time but instead it is the insulating dieletric covering to the cable that can cause issues to the signal when the cable is new. An ideal conductor is one that is purly surrounded by air but practically a good cable will have the lowest dielectric constant as possible (but will never be as good as air). Put simply the burn in process saturates the dieletric material with an electrical charge but it is the orrientation of the electrical charge along the cable in relation to the direction of the signal flow that causes the directional effect on the cable (similar to magnetic polarity). If you turn the cable around after burn in you will lose any benefits of burn in." These comments were posted in the X3 thread by @Light - Man and I'm of the opinion it's snake oil. Please discuss as I would love to be proven wrong so I can eat a piece of humble pie. I should also add that I purchased some rather expensive cables from Forza Audio Works and I heard zero difference in sound quality both from standard supplied interconnects from FIIO and the headphone cables supplied by the manufacturer Denon. They look better for sure but that's it. I believe the time has come for concerned music lovers, true engineers, competent physicists, academics, mag editors, etc. to take a firm stand regarding much of this disturbing new trend in the blatantly false claims frequently found in various forums. Cheers.