The quality in cords are solid on both. The FX40 has the lesser microphonics and the CKM500 has a short cord to an extender cord..Both have excellent build as well. Nothing like a monster earphone where you have treat your earphone like they were made of pure gold.
I don't see anyone having any issues so far as cords are concerned. Both are excellent cord wise no issues on both though the cord leading to the FX40 are thin but I am not worried they will snap easily. I noticed the build on my older FXC51 are exactly the same using the exact same materials and as many times as I have wrapped those around my fingers and unwrapped them and put them in a pouch and just used them they are just like the day I opened them from the box. Same with AT cords. I noticed the one thing the Japanese get right on earphone design is one of the most fundamental and basic ones which is..Having a basic solid cord design.
Edited by Dsnuts - 6/9/12 at 1:54pm