You still don't get it... your post came off as obnoxious and assumptive of Dr. Fang's intent; and no one had ever mentioned being unsure of these headphones for the sub-bass aspect alone, that's just your own misinterpretation.
"I'd rather have a new product as it is and go improve on that based on a general opinion (preferably logical ones as yours) and then have it fixed as opposed to just listening to just one, no offense. I'm just extremely hesitant about this mod not having ANY acoustical effects on reproduction instead of the boost in sub bass (off course without any added distortion in any HD order figures)."
Dr. Fang has ears of his own. He can determine for himself if Jerg's concern and fix are legitimate, and there is no harm to acting accordingly. It only serves all of us that sub-bass does get improved. And of course if this mod affects other aspects of sound, other than sub-bass, it will be noted by the testers and acted upon accordingly. Did you really think they would really overlook such a thing?
I assume Dr. Fang has ears of his own and even good measuring equipment. But he's also a businessman. "Deep bass" is such a sexy marketing term, conducted by the music and trend paradigms of today, which makes it easy to prioritize it over everything else. Though with products at this caliber, the difference in the talked mod would need to be marginal to satisfy a majority.
Apologies to Jerg. In no way of course are you responsible for the acts or comments of others. I'm not naming you the leader of this "wagon" I called out. Also, I don't dare insult that you're a noob at picking out these traits. But my point remains. You can't also be the grand daddy dogma (obviously not your own call) on this "issue": more listeners and objective measurements would need to be taken to quantify this. You having produced quantified results with HE500's a la Jerg pads, I have no reason to doubt your observations or debunk them. You clearly know what's up and what you're doing. I'm just saying, as good as your evaluations are, are not enough in my opinion to alter the production when it's not really out yet. Fang must have a good idea what he's wanted in this headphone and he's made to look bad by overstating something that is a bit contradictory and disproportionate (the sub bass vs. HE400, for instance, that measures pretty much dead flat to 30Hz).
Fang is a genius and I really don't doubt him. My first paragraph is a bit satiric. I owned his very first headphone, the wooden HE5, and it was in many ways just marvelous and had one of my favorite tonalities (though I don't really prioritize tonality, to a certain extent) of the Hifiman line.
I really do hope this mod is nothing but an improvement. I think the final test would be to listen to music that has no content below 50 Hz on both iterations and if you find them exactly the same, there are no negative effects on any other part of the musical spectrum. Have you tried this Jerg?
I'm sorry, I'll try to be more constructive from now on. Really would like to hear this in the future, unmodded or not.