IEMusic
Headphoneus Supremus
Yep, that is what I discovered. The damped nozzles are actually not really appropriate for the FD01/FDX1. Using circumferential damping attentuates the treble primarily, especially the upper treble. It proportionally effects the upper midrange (which is the offending factor for the FD01) less. By the time you have attenuated the upper mids enough, the treble becomes a bit dull and loses a bunch of upper treble air. I figured this out via a lot experimentation and analyzing Crinacle’s graphs. Using something like micropore tape over the nozzle attenuates upper midrange a lot more, and doesn’t affect the treble nearly as much. While using the most damped nozzles, I found the upper midrange glare still too much for me. Putting micropore tape over the most damped nozzles finally eased the upper mids, but I really missed the treble. I then tried the stock filter and applied a micropore tape type mod, and voila, the upper mids are not so edgy, but there is plenty of treble/air.I was using the blue filter on these FDX1s for basically this whole year, and I only tried the stock white filter with no damping once. Well, just yesterday and today I tried the white filter again, and the treble resolution I am getting is truly something special. I always use EQ with the FDX1, but that was with the middle damping blue filter. I switched to the white filter and adjusted my EQ settings, and it sounds cleaner, clearer, tighter, pretty much everything is improved, but the upper treble air is the most improved. Mind you, without EQ, the white filter makes them sound too forward from 4-6 kHz, so that area I EQ down by a good amount. But once that area is addressed, the rest of the range is just nearly perfect. What's amazing though, the treble resolution on the white filter equalized FDX1 sounds a lot like my Focal Clear! It really does sound that good to me.