Oh no, I agree on most of your points, except when the products are shipped out they all have (relatively) the same tuning which I'd believe to be that model's intended signature. I'm aware that in the R&D stage when they were developing this new 'mass produced' style driver that there were highly likely any given number of unexpected results that they had to further tune and adjust, but there was indeed a particular goal in mind. To quote Fang: "To be honest, we did tune HE-400 more "American sound" than HE-500." Based on my usage of it, I'd agree that's the signature it has - weightier bass and emphasized treble - which is perfect for hip hop, electronic and pop music. The upper mids dip is intentional and aids in pinpointing instrumentation and gives a sense of air, but the entire FR is not so aggressively curved that it's overly colored. I'd say it's still flatter than most, but also remains very unique and well suited for certain genres. Their production cost was was kept low in redeveloping how the drivers were manufactured, while still presumably allowing similar funding for R&D as their other models...I don't think they really cut many corners in the tuning process, especially when they've revised the driver a few times now. I think with upcoming models and further refining their processes, we may see more cost effective solutions with smoother/better/refined/different presentations, but there are still people out there that enjoy their HE-400 just as it is.
Indeed. Those are the intended aspects. I especially like how the HE-400 bass is done; it's not overly bloomy, with just the perfect decay. The bass never sounds like it's encroaching upon the midrange. The unintended are the spikes/dips in the treble. You can emphasize certain treble ranges without having spikes/dips. Fortunately, these are very easily remedied with a parametric EQ, for a smoother treble and more accurate timbre.