Summary: Hey guys!
I know this is hardly the first review of these to ever be posted and I'm pretty sure everyone has covered all of the bases by now, but I've decided to throw in my two cents as well.
This is my first review here, so please don't lynch me.
Pros: Good bass, wide soundstage, great detail
Cons: Stock pads constrict the sound, cable connectors will kill the cable in a couple of years, relatively heavy and looks could have been better
Summary: I'll start by saying that I have not owned a great deal of various pricey headphones. These are my best cans so far, but I've listened to a couple other comparable headphones that I'll mention later.
Pros: Almost even tonal balance, just the right amount of bass (and decent depth)
Summary: As of September 2014, the HE-400 has been discontinued, and it's successor, the HE-400i is being sold in its place. So why publish, or even read, a review now? First, there are many used HE-400s in the market and are being considered for purchase.
Pros: Great bass impact for an open-back planar. Unique sound signature.
Cons: It's strengths are a conditional double-edged sword.
Summary: These are warm but detailed. They are fun to listen to, like the other Hifiman products (I have a couple).
I enjoyed using them and got a HE560.
Will give them as a gift to somebody. They are nice open headphones for the price. I can expect they will enjoy them.
Still working after a year of use.
Summary: The title is not exaggerated either, but of course to get the HE-400s to that level you need at least a decent DAC and a tube or hybrid amp like the Schiit Lyr to even hear what they truly can do. Otherwise most amps will will work just fine with them!
Pros: Price, stellar sound reproduction, fairly easy to drive, very snug
Cons: Headband is the chokepoint in the price, it's just ok. fairly heavy cans, and they are completely open
Summary: EDIT: My opinions and views on this set of cans has changed a fair bit after more extensive listening. Please see the link below for my updated opinions on these headphones.
Summary: I initially had my eyes set on the HE-500s but after some research I decided that the sound signature of the HE-400s may suit my tastes better as I predominantly listen to EDM (Tech House, Minimal, Trance, GOA, Psy). Initial impressions out of the box were quite impressive.
Summary: After using IEMs almost exclusively, I decided that it was about time to step into the realm of full-sized cans. I wasn't about to spend $1000, but I still wanted better than mid-fi sound. My options were pretty limited, and it came down to either the HD600 or the HE-400.
Pros: Spectacular bass, rich, engaging mids, great soundstage depth, and excellent detail retrieval.
Cons: A bit hot in the upper-most treble, and some upper-mid coloration
Summary: First things first, there is a simple trick that solves all the complaints about the cable connectors - simply rotate each 720 degrees counterclockwise to build up some torque before you screw each one on clockwise.
Summary: HiFiMAN HE400
By now I think most of us are familiar with the history behind the HiFiMAN HE-series headphones. What started with a single model has grown into a full lineup, with prices ranging from $1299 for the flagship HE-6 to just $249 for the entry-level HE-300.
Pros: Exciting, bold sound with great bass, engaging mids, and mostly smooth highs,
Cons: Stock cable is annoying (but easily replaced), highs can be edgy at times