It has been almost 30 months since I got my X-Series and it appears that the right side of the NC headphones has given way. I noticed about 6 months ago or so that the right side was not as loud as the left side. I always assumed this was my hearing due to a right ear infection a few years prior, but now it seems that is not the case, since the volume is way too low. So now I am left with a dilemma, use the NC headphones until they completely die, use my MDR-V55s, bye new NC headphones, or get a used NC Sony player and use the headphones from that.
I am not keen on using the V55s since they are a bit too loud and would annoy people around me like on public transport. So for now I'm kind of stuck with broken headphones.