Having heard nkbg's HE-500's, I was tempted to check out the HE-400. A friend and I stopped by AVSF in San Francisco and auditioned everything they had on display. I believe the HE-400's were the only open back pair, and we both individually realized that nothing sounded even remotely in the same category as the Hifimans. Needless to say, we both bought a pair each and I've driven them with mostly with my iPhone 5, but sometimes with my Anedio D2. I wish I had more time to listen to them, but I can say without a doubt that despite the investment in my speaker setup (ANedio D2, Audiophilleo AP2+PurePower, Martin Logan Vantage ESLs, Jolida JD801 tube amp, RSA Haley power, etc.), there's more pleasure in hearing the HE-400s than I do with the speaker setup.
I agree with absolutk. I have had my HE-400 for about 6 months and I love them. Whether they are very detailed, or too bright, or whatever description you have for them, all I know is that I love the sound signature that they have. They have ruined me for listening to my speakers at least for music. My speakers are Paradigm Studio 60's, Studio CC590, 4 Studio 20's and 2 Servo 15 subs. My question for those of you who are familiar with the sound signature of the HE-400's is...What are the best speakers to buy that will replicate the sound signature of the HE-400's. I have never heard them, but I suspect that the Magnapans may be similar due to the similarity of the driver design. Any Ideas?