Thank you, but what's wrong with the cable and IEM's that I have? To my ears, they tell/show a CLEAR difference in the treble area, that can be improved. If it wasn't mentioned, then I will let you know that I have tried them all (regions) and have tried all FW's since page 8 in the original Sony wm-nw1 tread, so I do feel confident in judging the (small) differences in sound. But if truths to be told, then is properly my old ears! They used to be "golden ears", so even degraded in conception, I still hear most of what I'm not getting! Comes with great experience! The FE firmware from the great Mr.Walkman is above fantastic and I was just wondering if the final tweak could be hidden in some region upgrade! I highly recommend this tread as a daily go-to place if you have a Sony Walkman. It just keeps on giving. And again, thank you!The veiled treble could be your IEMs as I don't have that issue as the only difference between you and me are the IEMs.