Uhh, the first half of my post got lost when I hit quote...grr. I'll rewrite it here:
As a new HE-400 owner, I agree with almost everything in your review. They're very obviously darker than even HD650, and there is sometimes a timbrally "off" signature to the lower mids. Orchestral strings for example can at first try sound somewhat wrong, too dark. And yet every time I wear them, I find they grow on me more and more. Despite being darker than 650, in some ways they combine the warm, non-fagiguing easy to listen to sound of the 650 with the highly detailed K702's treble and level of engagement and "alive" feel.
I'm almost tempted to give HE-500 a try, since everyone seems to rave about how they're a whole different class of detail and neutrality and soundstage. I keep thinking, if these are this good, what must HE-500 be like? And yet the soundstage on the 400 seems as big as, if not bigger than my K702 which is famed for being
too big (not to me, but to many.) And I fear the HE-500 could end up as fatiguing or more fatiguing than K702 since it's often described as "sparkly" and "treble first." The 400's have a very cavernous feeling at times like I'm listening to the quartet from the back of a large, empty, concert hall in part from the darkness. How could it get bigger?
Also the comments on how revealing they can be seem to run contrary to the "dark" sound, not in a bad way, and also make me think that despite everyone claiming them to be "mid-fi" compared to their bigger brothers, they're mid-fi in nothing but price.
What intrigues me in addition to this comment, is that Bian hasn't gone out of his way to promote "HE-500 as superior" or "HE-400" as "a new lower cost, lower end planar" but instead promotes HE-400 as being more sensitive, and promotes the new manufacturing process that makes HE-400 so affordable. It makes me think that if HE-500 were made the same way and the silver cable, spare pads, and hard case were removed, they'd be able to compete at roughly the same price, just with two different signatures.
Though that may explain what I find oddly enjoyable about them. I've never owned B&W or other British speakers, but I have two JBL setups, and I love those Studio-L models for the money
They don't sound exactly the same, these are definitely warmer/darker in the lower mids, but perhaps they do both have similar signatures.