I received my HE-400's today. Got a used pair for $250 and they are in good condition with the white drivers. My other headphones are the AT-M50x and the Sennheiser HD-600, both of which I find very pleasing to listen to. I have to say, I was beyond disappointed by these headphones. The frequency response is actually unbearable for me.
Keep in mind, I'm coming from a TON of time on my HD-600's. I absolutely love them and I'm beginning to doubt that I'm going to find anything that I find truly superior to them. They just work so well for my purposes. I find the HD-600 through my O2+ODAC very smooth, clean, musical, and yet realistic. It sounds like I'm right there with the artists. Even the bass response is actually quite excellent with the HD-600. Bass guitars are easily picked out and very clean, it just doesn't extend really low into sub bass. That isn't a huge deal for me though, since sub bass doesn't really add much to the sound for me and rather just thumps on my ear drums. The mid range is obviously a strong point of the HD-600 and I would go as far as to call it gorgeous. When you get to the treble it's clear but rolled back just enough to not be too strident and harsh. I think I am probably sensitive to upper mids and treble.
Unfortunately, what I found with the HE-400 is that the midrange where many vocals occur sounds withdrawn and there is a very harsh sound at the frequency of the cymbals in most songs. Not only is it harsh, but it has an unnatural sound which I can't really describe, but it sounds like a digital sound rather than real (Maybe this is sibilance? It has this ringing "shhhhhh" kind of sound). It is so severe that it actually makes my ear drums physically uncomfortable. The cymbals are just clanging away right in my face in a way that I can only really characterize as harsh. This was the case both through the O2+ODAC and directly plugged into the MSi Z87-G45 motherboard (Which actually has pretty good onboard audio). The O2+ODAC seemed to make it worse actually, where I find that the O2+ODAC improves both my AT-M50x and my HD-600 substantially. I also found the HE-400 significantly more uncomfortable compared to the HD-600. There's no way I could wear those for 4+ hours like I do with my HD-600's.
I was really hoping these would be a good addition to my collection and I was excited to try my first planar magnetic headphone, but they sound so bad that I am probably going to return them immediately. Perhaps I got a bad pair, but it's not like they lack clarity and they don't sound like the drivers are blown out. They just sound like they have a nasty spike in the frequency response curve which dominates the sound and makes it unenjoyable for me. They also lack the natural sound of the HD-600. I did mess with EQ some, but I found that it just made them sound even less natural. Even the AT-M50x's frequency response sounds superior to my ears. I will say that the bass is pretty good on the HE-400, but it is overpowered by that nasty behavior on the top end for me. Maybe I am just overly sensitive to this frequency range? On the bright side, it was a learning experience and now I know a little bit more about my own preferences. I'll be interested to hear another HE-400 on a different person's setup sometime to see if it was just a bad pair.
