Neutrality and detail you say? I don't want to jump the gun here but I've had my he4 plugged in for... 45mins and that's what they are. Like a baby of a DT880 and HE400, except that treble spike and female-vocal mid dip of the two respectively canceled each other out. The bass has the same impact and depth but less in qty. EQ-ed and this thing can come close to the he400's bass. I feel the soundstage can get wider... I'll have to do the grill mod on this as well but for now I'll work em to 150hrs. Cheers!
I'm interested in getting an HE 4 my self as well, simply due to what I hear about it!
With regrads to he HE 400, it is better than the dt 990, but when your running the HE 400 on sub par gear, like an oDac or an M Stage, it doesn't perform well enough imo to merit the price. So I don't recommened the HE 400 to new members seeing as for the money, the dt 990 performs a lot better with things like the E17 and the oDac more so than the HE 400. Now for some one who has something like a Schiit biFrost or an Audio GD amp, the HE 400 out of that gear is a step ahead of the DT 990
How ever, I'd really like to try the HE 4. Although I'd kinda want another Toxic Cable and J$ pad for the HE 4 same as what I used for my HE 400
Off topic, but, from what I have read, to make the Hifiman Orthos perform their best, they are run directly off of speaker amp outputs, so they are power hungry. A Bottlehead Quikie preamp, in front of the amp, has been proven to work very well. I just question the comfort of the Hifiman products, their weight has been the subject of a lot of discussion. I really like the fit and comfort of my DT880/DT990, and with my detachable cable options and tube amp I am well satisfied. They sound nothing like the stock cables, but that is my opinion!