Have you ever had the opportunity to hear the JVC DX1000? Considering your comment here about the TH range brightness, the JVC seems like a logical one to try due to being a warmer sounding sealed headphone - with an overall far smoother sound than the Fostex TH600/900 range and higher up Ultrasones like the Pro/DJ - for me at least despite owning and enjoying two pretty bright headphones. It still has a bit of wonkyness in the frequency range seen in the one and only measurement I've seen for it so far
Either way the XC and FAD are on my own to hear list - I have seen many others that think the same way as yourself on the XC overall quality for the price. I love my TH600, but I note the treble shrillness every time I listen to anything outside the realms of electronic or pop - looking at your measurements the TH900 are less bright.
If you are referring to the Alpha Dog, then for me without the doggie treat mod they seemed to be almost a planar HD800 in terms of tonal balance. They had a shrillness to the treble that annoyed me a bit not as bad for me as the HD800 without modding.
Edited by UNIFi - 4/12/14 at 8:08am