After years and months of reading and listening through
Sennheiser HD 25 SP II (2007-now)
Sony IEMs (2012-now)
Sennheiser Momentum (2014 sold)
Beyerdynamic DT 1350 (2010-2014 sold)
Beyerdynamic DT 990 600 Ohm (2014 sold)
..I finally bit the bullet and bought a brand new Fostex TH 600. I am pairing it with my new Xonar STX with its decent Burr Brown DAC. It already sounded breathtaking with the Beyerdynamic 990, but these were open cans, and the bass and highs were too much for Soundcloud typical Sound (genreless, but bass heavy). With acoustic Jazz the DT 990 were definitely quite nice.
Comfort of the DT 990 was unparalleled, but comfort and fit of the Fostex is quite good. The leather-imitate of the TH 600 is high quality egg-shell and ultra-soft. The cups are not as big as with the Beyers, but I have giant ears and they still fit into the cups, could be larger. I am barely touching the sides, yet even "barely" can develop into a huge annoyance over time. Too early to tell. The headband could be thicker for a can this weight, but its manageable. In terms of comfort the Beyers 990 have the clear edge. I wish the Fostex were as comfy as the Beyers. Fortunately construction quality is better or at least as good compared to the Beyers. The Fostex are very solid and high quality, worth their money construction-wise.
Now the TH 600 sound nice out of the box, not quite as open sounding as the DT 990, everything is more controlled with the TH600, highs are much more enjoyable on the TH600, the lower bass is very defined, very prominent, not as over-the-top as with the DT990 600 Ohmers. The mids on the TH600 are just about right, very spacious, almost as prominent and in your face as with the DT1350. I'm a sucker for good mids - Nice! For a closed can, these sound pretty open I must say, but they are closed and give you this closed-from-the-world feel. They develop no heat. I guess one has to own both types of headphones.
Soundwise this is the first hours listening to them, so these will need a couple of more days until they open up and more accurate comparison can be made. But equalizerability is great with the PulseAudio Multiband, which does equalize Linux-wide, a highly recommended tool. (Can't substitute the pro-EQ from Traktor or Mixxx though). Again: These are nicely eqalizable, much more than the V-shaped and sounded signature of the Beyers 990. Excellent switch I made, very happy.
Neutral, yet not too analytical spacious, well-defined, dark and open sound. Excellent mids. Little Hiss. Well made cable.
Headband could be thicker for its weight, 100% Black Coloring makes them rather dull looking.
Emotion-wise they suck you into the music right away, you will start listening to tracks you formerly skipped. You will continue to listen to tracks that sounded to harsh on the Beyers and where you skipped ahead. Do the goose-bump you? Yes, and your head will be shaking. Tinnitus included.