GU1DO any chance you could post a picture of your earpads and their thickness? Having handled a few of these, what's become apparent is that small variations in the earpads are possible, due to their hand made and hand stiched nature. Most variations are minor, but some can be more damming.
I actually returned one pair because of ear pad stitching alignment issues, as well as my left and right earpads being different thicknesses and shapes.
Sony were completely awful in dealing with this issue, and claimed they were not faulty even though they were different to what was advertised, different to other earpads on other Z1R's, different to each other (left and right), and also to how they should have looked based on all marketed material.
If I didn't love how they sounded, I would have never purchased another pair out of meagre principle. It isn't so much that a QC issue with the earpads existed that annoyed me, but Sony's complete reluctance to acknowledge it, or replace them.
Sony went from claiming they couldn't help because I didn't request assistance in the first 14 days (even though I actually did in the first 7 days of purchase) ,to then claiming my earpads weren't covered because of physical damage (even though they arrived mis-stitched and shaped the day I opened them), to finally claiming they simply weren't faulty despite acknowledging that they looked different to each other and to what was advertised. This entire process took 2 months, as their response rate was around an email response every week to two weeks. Thankfully in the end my retailer allowed me to return my pair even though the 30 day period had passed.
I'll post some images showing the earpad issues later, the same ones I sent to the engineers.
The weird thing as well is that the thinner or slimmer the pads were, the more forward and intricate the sound was, perhaps less bassy too, so there was actually a very slight difference in sound as a result of the earpad differences. This was more obvious doing A/B switches with the other earpads from another pair I had.