Serious Sound
Very Natural and non fatiguing
What a comfort ...most comfortable IEMs ever used
Highs: revealing and warm
Mids: exceptionally detailed
Lows: Now I have read some reviews saying sub bass is missing...not for bass heads...blah...blah...I say if you crave for the bassline in the song..you can clearly hear through these without even muffled a bit...very very extraordinary presentation of low frequencies...example in the song feel right by Mark Ronson the bassline is extremely audible with clear note represtation...
This is highly recommended for budding audiophiles, music enthusiast and for regular commuters as they provide solid isolation also.
Must Buy !!!

The sound is mind blowing at the price range, although the piece they are giving at the price of 2k is Hifiman RE400a, that doesn't have braided cable, volume controls and the metal slider shown in the pictures. Kindly mention this in the description, HeadphoneZone. Hyper clarity in highs, mids and lows, the lows are not tuned for bassheads though. Appreciable soundstage and excellent sound separation, the flat sound signature being the USP of Hifiman-RE400. The small size and design of the earphones makes for a very comfortable fit, and the small bi-flange ear tips are quite good. The cables look and feel quite flimsy, so handle with care is an understatement in this case. Overall, keeping cable flimsiness aside, an absolute bang for the buck.

A sound signature like this, flat and accurate tonally correct is definitely not expected from an in ear headphines with 8mm drivers. Truly a surprise!

I mostly listen to classical.music and instantly caught on to previously muted undertones, the scratch of the players fingers on the guitar, the gentle creak of wood on the piano when I used these little monsters with my FLACs. They have a decent soundstage that extends beyond your ears to somewhere around the range of a helmet ( just didn't expect that on these small drivers). Noise isolation is passive but they rest inside the ear and provide a good seal thereby eliminating most noise in my experience.

The only negative is microphonics and cord noise as this definitely something you might want to consider. Don't consider them if you want to stay active like marathon running or gymming while wearing these as the cord noise might interfere with your enjoyment.

Sound quality is well worth the money, that is if you listen to instrumentals and high quality codecs. Otherwise you might want peppy headphones as these are really flat and neutral sounding( some people do enjoy it!)

My Music Info:
I listen to a lot of Metal, mainly Thrash and Black metal, in a 18 hour day I listen to music for about 8 to 10 hours and these are truly a great pair of IEMs.

My Source Info:
Most of the time these are paired with my Fiio E07K DAC/AMP, for a brief time they got used with my OP3 and for around 1 hour they are used with Fiio X3II Hi-Res Player.

My Source Files:
Mostly I use Hi-Res Flac when playing through my amp or player.
320Kbps Mp3 are used for playback with my OP3.
All my sources and source files puts me in a state of bliss with worst of my earphones and let me tell you these are my 4th best earphones.

My sound Preferences:
Due to the nature of my musical interests a neutral sound is what I prefer the most but times comes when I tilt towards a little bass heavy EQ settings to accentuate Bass guitar.
Everything that I listen is played on a single EQ setting.

My review:
Bass: Well maintained, tight and responsive.

Mids: Male vocals are clean, female vocals are a bit harsh some times.

Highs: Cymbols are definitive and shimmers a lot but in a good way.

Sound stage: Every thing is placed where they should this is the only place where these outshines the Shure SE215s and defines the music a bit more.

The re400a are really good sounding earphones, they come with a lot if accessories. Choose the ear tips wisely cause they'll have impact on sound.
The build quality of earphones is really good but not of the wires. Mine broke after 1 month cause i am rough user, but i used jugaad and just tied the wires again and they're still working fine.

There are only 2 earbuds provided in the box where there is 7 mentioned along with pics

Audiophile/Purists budget in ear headset.
Almost uncoloured, Natural sound produced by single driver unit. Hats off to Hifiman.
People looking bass or V type sound signature will get disappointed.
I have used Sennheiser cx 180, cx275s. They Sound V type not to my taste.

Akg K240 mkii and this Hifiman Re400a are my current favourites.

I prefer uncoloured Natural sound and with 1999 bucks you get audiophile grade product. Built quality is better than Sennheiser but with 1 year warranty only.

You will get headphone case along with it.

Bought from authorised Hifiman seller headphonezone.in @1999/.

This may be perfect product for your smartphone listening purpose.

PS: I use Akg K240 mkii with my FiiO X3ii.