I just thought I would add something--
I was looking for a headphone as a gift for someone for some time in the sub 200, closed and portable category. I demoed some stuff in the trek to find the right one (HD280, HD380, SRH440, HFI680, HD-25 I-II, SRH840 and the previously owned PX 360 as well as currently owned HD448) and none of them had just the right sound for their tastes. I couldn't settle for any of the options as a well rounder... it seemed like each headphone had some really nice strengths but just weren't versatile enough for me. I was leaning to the SRH440 when I stumbled upon these KNS-8400. Honestly, not only are they very portable, easy to drive, very lightweight, closed (and ACTUALLY isolate decently), and extremely comfortable, they sounded
great for what I was looking for. Of the options I listed earlier, these did the best at not emphasizing any particular part of the spectrum, but just laying out the sound. Somehow, while doing this their sound had energy! I'm not going to say they are ruler flat or anything like that, but the extension is good, the separation is solid (for a closed set), and they do actually sound neutral to my ears... but not in an unnatural way. I found my winner-- these are certainly a "sleeper".
If I wasn't so partial to my HD448, the KNS8400 might have replaced it as my "plug and play" headphone. I just prefer the warmer, darker sound of the HD448 for extremely laid back listening sessions when the music shouldn't grab my attention as much-- like when studying.
The KRK KNS-8400 gets my endorsement, for whatever that means. I'll have them for some time before I gift them off (for Christmas), might spend some time with them and write up a review. She won't mind