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!)
Very good sound quality. One star less for build. I don't think its for harsh use bcz of build quality. Overall I am very much satisfied for amazing sound quality
1) mids are very good.
2) best for people who listen to classical music.
3) highs are clear you can hear all instruments with details.
1) could have had wider soundstage.
Not for bass heads.
I have one complain regarding the free comply tips, they are good but in the first week I have already managed to peel out the outer layer of tips, which clearly shows the quality of tips.
RE-400 are an amazing piece of earphones. It took about 15-20 hours of burning in to see their full potential. They are terribly well balanced and neutral.
Not meant for heavy bass requiring music like edm but rest everything sounds great. I listen mostly to rock, alternative and fusion music and these truly bring about the richness in every song with me hearing sounds i didn't know were there in the song. Great clarity and the sound staging is also very decent.
They are also comfortable. Haven't worn them for a long stretch like 4-5 hours but for the 1-2 hour stretch they were very comfortable. They are also very light.
My only concern is the durability. I haven't read much good about Hifiman's durability. The build quality isn't what i expected and these feel a little vulnerable to breaking early. Another thing I found(not that important) changing the eartips is a big hassle.
Overall if you want to hear the music as it naturally sound. Go for 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.
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.