As far as the Fostex mods, the Ori is as close as I've found to an Eikon. Not sure which is lighter, but I think it's the Ori. I've been fortunate enough to spend a bit of time with
@Pharmaboy 's pair, and they are a damn good set of cans.
EDIT obviously wood choice will make a difference. I believe a Padauk wood Eikon weighs 550 to 600 grams, and Cherry and Walnut Oris are 450-500 g if that helps
Well, it seems the Ori is not appreciably lighter than the Eikon. Below are 2 quotes from Zach. The 1st concerns the Ori (originally called "Omni"); and the 2nd concerns the Eikon:
1 - "Both Cherry and Walnut Omni's are 450-500 g in weight. There is some variance but all my sets weigh in that range. You can add 60-100 g for Blackwood."
2 - "Because the cups are made of solid wood the weight will vary slightly, but generally the weight will be as listed below:
Cherry: 490-530 grams
Padauk: 550-600 grams"
Not sure what my ormosia henryi weighs. No doubt more than cherry, but probably not as much as blackwood. And now I know what my padauk Eikon weighs...
I think the Ori is one of the most interesting closed back headphones around. I love its sound, including really epic bass, far better soundstaging than most closed backs, and both mids & treble being tonally rich & full of information. People knock the treble of this Fostex driver, but I what I hear is all good. The Ori was my 1st planar headphone, and it jump-started my interest in planar HPs that persists to this day (I later acquired 3 open-back planars & currently am obsessing about a 4th).
Guess I'm one of the lucky ones--the weight just doesn't matter to me. I never feel neck strain or any ill effect of listening to these ZMF designs. When I switch to something lighter (ie, HEX v2), I feel the difference in weight, but no particular benefit from lighter weight.
"Lucky" because IMO both ZMF headphones sound amazing--as does the Auteur (finally heard a teak pair the other night, courtesy of
@jinxy245, and was very impressed). Looking forward to hearing the Verite & Aeolus at CanJam. All these designs are relatively heavy, in the league of various LCDs (which I also own & appreciate).