I have been using RE400 for over few months now. these are rather well known and well documented so I will only put stand out points that I think make it unique.

Build:

Light weight, made out of aluminium. Chord is fabric covered below y splitter. above that its plastic. no microphonics if i wear them from above my ears. Otherwise it can be bothersome. Jack is 45 degree. Overall looks solid and mine is working well without problems.

Comfort and isolation:

Comfort is above average. Isolation is great if I use comply tips, otherwise I think its above average. I do need to insert them a fir bit in my ears to get a good seal, more than other IEMs I have used.

Sound:

Two words that best describe the sound is: Tactile and balanced.

Bass is present and slightly lifted thus gives instruments slightly more realistic feel. Bass is Fairly transparent and conveys what was played well enough. Its fairly tight, though I do find sub bass lacking a bit.

Mids are well balanced with bass. Its not a huge soundstage and mids sound rather intimate. Slightly lush, overall maintain neutrality.

Treble is extended and can be delicate or harsh depending on source, with fair amount of resolution. Again nothing alarming, its not a bright sound to my ears.

Amping: Rather strange in amping department (I guess its common with iems). Sounds best out of my PS Vita, a gaming console, compared to my phone or amp. Detail retrieval drops when used with either compared to my other full size hps, that sound best out of amp.

Value: Overall amazing. I has quiet a lot of hype surrounding it. I do think if you factor everything, comfort, accessories, sound, its very good $100 iem. Taken only in terms of sound, will it beat a $200 hp? I don't think so. But I do think its very competent hp for $100 and a great value.

HiFiMAN RE-400 Waterline - Ultimate Review w/ pictures
 
1)Equipment and cabling
 
a)Headphones
 
HiFiMAN RE-400 Waterline
 
Type: Closed, tiny, in-ear, dynamic driver monitor
Frequency response: 15 - 22.000 Hz
Impedance: 32 Ω (may vary by up to 10%)
Efficiency: 102 dB
Weight: 16 g (with cable)
 

 
This was my first in-ear-monitor purchase. Also the very first IEM made by HiFiMAN. Their cheapest headphone yet, priced at 100 USD. How will these compare? They share the general HiFiMAN house sound and neutrality and offer good build quality as well. There is a dedicated RE-400 review below where all will be discussed and compared.
 
b)Amplifiers, Digital to Analog Converters, Preamplifiers and more
 
Fiio X1
 

 
The X1 is an amazing little unit. In fact, that is an understatement. It's been a very long time since last time I was this overwhelmingly impressed by a $100 unit. The UI is excellent. Very intuitive, rather snappy and easy to navigate. Honestly, I was not expecting an in-house developed UI to be this good, but it every bit is, and it also reads all the formats that I've tried without any hiccups, including associated CUE files. The DAC is absolutely stellar, using an impressive Texas-Instruments PCM5142 DAC chip. The amp section is also pretty good, utilizing an Intersil ISL28291 amplifier buffer. The 2.4" TFT display is plenty big and easy to read, providing all the necessary information even in direct sunlight. It is slightly washed but still plenty good for the price. Among other things the player offers a 7-band equalizer [from -6 to +6 each], gapless playback, sleep timer, usable buttons when screen's off or volume limiting. There's no date and time yet though, which I find a bit strange though not all that important.
The build quality is perhaps the most spectacular aspect - holding the unit in your hand boasts confidence and there's good heft to the unit. The X1 features a fully-aluminium body with very tactile buttons and quality that's hard to find on products costing much more. The Fiio also comes with a screen protector and a rubber protective case, along with a charging cable. The battery life is around 12 hours a run, for a 4 hour's full charge.
There's also the line-out function using the headphone jack, which offers the possibility to use just the player's DAC with a more beefy portable amp. Although I already found the X1's amplifier to perform favorably with reasonable headphones from IEMs to full-sized cans.
I am really struggling to find anything to criticize here... Did I mention it was a hundred bucks?! In a long time, I am left with only fuzzy and completely positive feelings, while using the unit feels just as enjoyable. I really don't understand how Fiio did this, but currently I consider the Fiio X1 a jack-of-all-trades and wouldn't hesitate recommending it to anyone looking for a lovely little DAP and as someone coming from the pretty good, very-happy-with and tried-and-proved Sansa Clip+, I think this is some very high praise.
There's more competition on the way, however 
 
Pros
+ build quality
+ performance
+ User Interface
+ price, price, price!
+ line-out function
 
Cons
- no time & date, slightly washed-out display
 
Overall 9.5/10
 
Fiio E11
 

 
A very versatile little amp.
Slightly warmer tonality with smooth highs. Decent instrument separation and soundstage. Ideal for most portable headphones. Fits your pocket nicely. The stock battery lasts about 8 hours.
Packs lots of power. For 60 bucks it is hard to beat. Fully aluminium casing (like all amps here). Has a bass boost switch as well as a low/high gain one. Fiio is getting very popular among audiophiles these days because it offers good quality throughout for the price. The E11 is no exception
 
Pros
+ Small
+ Decent battery life
+ Price
+ Works with most headphones
 
Cons
- Cannot charge while playing
 
Overall 9/10
 
[A/N - The amplifier was not tested with this IEM and this was only meant as an informative review. An amplifier is not needed for these if you already own a decent DAP]
 
c)Cables
 
The RE-400 cable (not removable)
 

 
2)Unboxing and accessories
 
 
The RE-400 comes in a rectangular shaped glass-like box. The inside of the box is cut for the individual pieces found inside, that is the headphone, 6 different tips (one comes pre-installed) a clip and that’s about it. The box itself is made from two pieces and these like to fall apart a lot. It doesn’t really hold together well and it really contains only the most basic things. Although they come cheap, a better box would be nice.
 
Update: Now comes with a nice hard-shell carrying case, more ear-tips and even two pairs of foam tips [all reflected in comfort/fit]. Packaging rating improved.
 
Package overall 8.5/10
 

 

 
3)Design, build quality and comfort
 
a)Design/Build quality
 
I am glad I can say that the build quality of the RE-400 is the best yet of all the HiFiMAN headphones. The headphones look finished and sturdy and could definitely take some abuse. The only issue I had was with the jack of the cable, which snapped, but this was mainly my fault and was briskly replaced with a different jack by my local dealer.
The cable is a bit kinky and likes to get stuck on clothing but is in turn rubberized and of nice quality.
I am definitely happy with the overall feel of these headphones, from top to bottom they feel like a well-made product.
The shells are made of aluminium and feel great in the hand. The cable, on the other hand, ...
 
Update: The [cable's] build quality unfortunately did not hold up to initial expectations. The shells are not to blame, they are made from aluminium and feel very sturdy the cable, however, is a different story. I had the jack break once and the internals of the cable [meaning the thin wires that are underneath the sleeves] are probably significantly damaged. I need to stress that I took very good care of the IEM, but the cable has a will of its own and it coils down all the town, which is probably the culprit of it. Still it is a thing worth mentioning and a nominal design flaw. I'll bump the build quality down by 3. 
 
Update 2: Since my inititial issue many months back, these headphones have been holding rather well, though the cable is still microphonic and tangly... I will boost the build quality up for now, assuming the teething problems have been fixed by now.
 
Build overall 8.5/10 (Build quality 8/10 Design 9/10)
 

 

 

 
b)Comfort
 
Only one of the 4 stock tips fit me. They came preinstalled on the monitors. Changing the tips is not that hard but since I don’t have any other tips available right now, the stocks will have to do. They isolate quite well. Medium insertion seems best for sound quality and comfort, isolation. They fit in nicely so I can wear them for hours, adjusting here and there. I was worried about the fit a little, but everything seems ok. Decent comfort and fit.
 
Update: It now comes with more tips, including a two pairs of foam ones.
With them, the white middle-sized tips [pictures further down] currently offer the best comfort/fit ratio. I want to stress out that fit is really important for the overall balance and bass presence. Luckily, there're many tips included now, so finding the ones that fit shouldn't be a problem anymore.
 
Comfort/Fit overall 9/10
 
White Tips
 

 

 
Stock tips
 

 

 
4)First and further impressions
 
There wasn’t much burn-in with this IEM so to speak. Back then I still used my trusty Samsung Wave I (S8500). For now, there is no external amplifier to speak of. I am considering one for the future, as I will probably need one for the RE-600, which I’ll be buying (and subsequently reviewing) most likely. Initially, I was really surprised by how good the sound was. The vocals were butter smooth, midrange was full and lush, bass was nicely detailed, slightly lacking in depth and punch, but very nice. Highs were very smooth but still didn’t lack excitement. Soundstage width was great, extending even out of my head slightly. Instrument separation was still top notch like with all other HiFiMAN. I didn’t perceive any burn-in with these, really, other than changing my phone for a Galaxy Ace II.
They certainly didn’t disappoint.
 
First impressions overall 9/10
 
5)Sound
 
Update: I am now using a Sansa Clip+ and the RE-400 are great with it!
Update 2: I've now purchased the Fiio X1 and the RE-400 is simply stupendously great with it. I will change the review scores and corresponding sections slightly to reflect this marked perceived improvement. I am also using a different set of ear-tips, which come with them now [see pictures] and those give me nearly perfect seal. This, coupled with the X1
makes the RE-400 a seriously amazing pair of IEMs for the asking price.
 

 
a)Low-end/bass
 
Pros
+ Tight
+ Lots of detail
+ Non-intrusive
 
Cons
- Can be a bit soft at times
 
Overall 8.5/10 – The low-end of this headphone is pretty good, sounding pretty much tight and punchy, very much in line with the bigger HiFiMAN headphones. As such, it also bears the same relative shortcomings - coming off a bit soft in weight and punch at times, with a bit less oomph than I'd like. But the reward is that the bass always remains tight and in line with the other frequencies, never sounding overbearing but not sounding deficient either. The IEM is certainly potent and depending on the recording it can drop some serious bass, punchy and extended, but still controlled, mind you. Now that I've achieved a proper seal, I don't think the bass is lacking or weak anymore. Instead, it is just the traditional HiFiMAN signature bass I learn to really appreciate.
 
b)Midrange
 
Pros
+ Balanced across
+ Natural and sweet
+ Instruments have their space
+ Pretty great detail retrieval
 
Cons
- None
 
Overall 9.5/10 – I don’t personally take any issues with the midrange. In many aspects, it is like a full-sized HiFiMAN lite. It lacks the ultimate spaciousness and air of the full-sizes, but it still offers an absolutely even instrument reproduction across, with a balanced but still dynamic sound. The midrange is slightly forward, just enough to keep its bite but smooth enough to not be fatiguing and providing hours on end of enjoyment. This is the area where this headphone definitely shines. 
 
c)Vocals
 
Pros
+ Nicely extended
+ Sufficient presence
+ Absolutely non-sibilant
+ Clean
 
Cons
- Lacks some air
 
Overall 9/10 – The vocals work rather well for my tastes. They are present at all times, without ever sounding muted or constrained and still very much smooth and sweet. There is not a massive amount air but there is a enough to make this IEM sound more airy than most sealed headphones. They have a fair amount of extension, but not overly so and this contributes well to the smooth signature of the RE-400. These IEMs are not bright by any means, but they aren't dark either. Still, they play nice with everything I've thrown at them, producing a slightly warmer but still fairly neutral sound.
 
d)Highs/treble
 
Pros
+ Natural
+ No added presence
+ Just enough extension
+ No harsh moments
 
Cons
- Lacks the last bit of extension and air
 
Overall 9/10 – The highs work the same way as the vocals and midrange. They are sufficiently extended with some slight roll-off to prevent them from ever sounding harsh with cymbals for instance but there is enough presence there to carry all the necessary information without overdoing it. Electric guitars never sound edgy either. Together with the rest of the frequencies they offer a smooth, balanced and forgiving experience ideal for traveling or relaxing at home or work. They do many things right without doing any obvious wrongs and as such they are hard to put down.
 
e)Soundstage/Instrument separation/Imaging
 
Pros
+ Great width
+ Stellar instrument separation
+ Smooth and even tonality
+ Plays nice with everything
+ Detailed
 
Cons
- Lacks depth and height
 
Overall 9/10 – As I said, the tonality of the RE-400 is very smooth, while offering great detail retrieval and musicality. Due to the tight bass, I wouldn’t recommend them solely for hip-hop or rap, though they still perform reasonably. These offer just a sibilance-free, engaging but relaxing experience. Basically a toned down full-size HiFiMAN in all aspects with some slight roll-off at both ends. The instrument separation is excellent and the soundstage width is likewise great. Center stage is very coherent and does not exhibit any oddities or unevenness and nor does the rest of the stage. The imaging is likewise excellent. 
 
f)Recordings sensitivity
 
Overall 10/10 – These belong among the more forgiving headphones for sure, and they're probably  the most forgiving “audiophile” headphone I have heard so far. I never had to turn the volume down with these because of harshness or sibilance. The interesting thing is that it still extracts a very fair amount of details and it does it really well without any obvious peaks or recesses, which usually isn’t the case with other headphones. HiFiMAN has managed to master the balancing act with these, offering great detail retrieval with a smooth tonality - something that is very hard to achieve.
 
Overall Sound
 
As such the RE-400 belongs among my favorite headphones - with tight and punchy bass, present mids and smooth and extended highs. Coupled with good detail retrieval, good soundstaging and remarkable imaging and separation, these fit right into my favorite sound signature, with very few minor imperfections that are easily forgivable based on the price/performance ratio these little puppies offer.
 
Sound overall 9/10
 
6)Gaming
 
RE-400 – N/A (I wouldn’t consider an IEM for gaming, really. Feel free to give it a try if you want though and report back :})
 
[HE-6 and Pro 900 have been reviewed for gaming, to see the games that I've tested and how those did, check their individual reviews on pages 1 & 6]
 
7)Portability
 
The RE-400 would be my top pick for portable headphones. It doesn’t really need any sort of amplifier to sound top notch. The signature also works really well when you want to focus on other things or just relax. Every song works here so you don’t have to worry too much about quality and specific playlists and as such it could very well be your perfect travelling companion.
 
Portability overall 10/10
 
8)Unique trait
 
Smoothness
 
The tonality of the RE-400 is one of smooth nature and rich detail. This tonality is particularly inviting to me because there are not all that many headphones with such traits. There is a bit less highs and vocals presence and bass than with the HE-6, making it similar enough in tonality but different enough in presentation. If you want a totally smooth pair of in-ear monitors this is the right one to choose. The RE-600 should offer similar tonality as well with more body and less roll-off at either end. W will soon find out 
 

 
9)Songs and genres
 
[see HE-6 Ultimate Review, page 1]
 
10)Value
 
This was my very first serious IEM purchase. I was a bit skeptical about just how good such a tiny driverlike this one can sound. I was quickly reminded that at HiFiMAN they simply know what they are doing and how to produce top notch sounding products. Even in direct comparison with full-size offerings, this little fellow muscles up and certainly holds its own ground. It is not as extended or airy or spacious as its higher brethren but the price is much more feasible and honestly, an IEM just cannot sound that way. Still, for just around 100 USD you get a sneak-peak into the HiIFiMAN house sound. The performance was smooth throughout coupled with a highly enjoyable signature straight off your DAP's jack. I've tried an amplifier to see how much difference it would make, and there was none - the X1 just sounds phenomenal with these. As is, this headphone is simply too good to resist at the price point and everyone who is looking for a very decently priced, neutral-warmish IEM to get, you might as well pick this one up. You certainly won’t regret it.
 
Overall value 9.5/10
 

 
The joint point
 

 
11)Conclusion
 
This is a seriously good IEM, absolutely suitable for portable use. I am not a huge fan of IEM due to their inherent shortcomings [lacks the soundstage of full-sized headphones, etc].
I am one of the few who don't mind carrying around full-sized headphones, provided they are not difficult to amplify well.
Still the RE-400, being a bit of my IEM premiere, did not disappoint me and I sometimes prefer it to full-sized headphones when I want that smooth, detailed yet non-fatiguing sound.
For a hundred bucks, this is a great, great IEM, even though the cable could have definitely been better made, at least initially.
 
RE-400 final score 9/10
 
12)Special thanks: 
 
[See HE-6 Ultimate Review, page 1] 
 
Kindest regards and thanks to anyone reading this. Hope you liked it!
Luke, the reviewer

 i totally would like to believe that there is no earphone brand as admired as hifiman , at least admired by purists , and the small and cute re-400 is not an exception , its a total value phone and every penny is best invested .
 yes these phones lack some sub bass and dont hit big like a bass phone cuz its nothing close to it , it is more of a mid centric phone and is as balanced as i wish , now im not a fan of booming bass so i like re-400 more than S5 or ckx-9 , sound stage is good , i like it , good depth but narrow , vocals are a bit veiled thats all i can fault about , instruments are really clear and i love this highs , good energy and good extension , sonically these are awesome and extension in the top end is exceptional .
 i love it as much as my er-4p , and i think if re-400 were to grow up , it would have become an er-4p .
 
 a brainwavz S5 comparison can be found here . similarly priced but far more different in other things .
http://www.head-fi.org/products/brainwavz-s5-in-ear-headphones/reviews/11371

After I bought the HD 598s, I was soon looking for a portable set of headphones or IEMs for casual use on the bus or outside. Sure enough, I found the lauded HifiMAN RE-400 to be an interesting option and even with concerns of durability and the possibility that a neutral sound signature wasn't for me, I bit the bullet. Were they worth it? 
 
Comfort, Design and Accessories:
 
I found the RE-400's to be well-designed overall, featuring a rather large plug and a cable comprised of both cloth and rubber. The drivers and the casings surrounding the drivers are rather small, which is a definite plus for portability. They also come with a wide array of tips and a rather convenient little case that can hold some extra tips and the RE-400 itself. I myself found most of the tips uncomfortable and stuck with the smallest tips but with the plethora of choices at hand, one can easily find a fit comfortable for them. To note, the RE-400's can sometimes be annoyingly microphonic at the rubber part of the cable in particular but this can be somewhat avoided by wearing them over the ear.
 
Though I've heard the cases of unpleasant durability, so far that doesn't seem to be true and these seem like they'll last easily for another two years. As far as comfort goes, I find the RE-400 to be satisfactory but not perfect. The fit is fairly comfortable but over time it can get warm and unpleasant in my experience for listening sessions over an hour or two. Perhaps with other tips this can be remedied but I haven't found that to be the case. Isolation for the RE-400's is average for the most part and even with a good fit, much of the background noise around myself is still discernible.
 
 
Sound Quality:
 
Overall, I found the RE-400's to be easily satisfactory for my musical listening purposes. The sound signature of the RE-400's does seem to be neutral and balanced but as many have noted, is also warm and sweet which makes the RE-400's sound detailed yet not analytical.
 
The treble of the IEMs is well-extended and definitely unfatiguing with a small amount of sparkle in the upper regions of frequencies. Drums and cymbals sound detailed and well-presented without being overly detailed and sibilant. However, this can at times sound a bit too smooth and without more sparkle, instruments and electric guitars in particular don't sound completely realistic. (when I hear a violin, I expect to hear some bite on the sustained, higher notes but the RE-400's present them without much harshness)
 
Mids on the IEMs are wonderful, bring very realistic and slightly forward in its presentation. In particular, guitars and vocals sound beautiful and almost immersive with detail to attention in the depth of vocals and string instruments such as violins and cellos. Most impressively, I can hear the breaths of vocals and little footsteps which I hadn't heard before in my music. However, male vocals, though sounding beautiful can come off as a tad dry and not quite as lush as I'd like but at this price point, it's to be expected and so this is a very small concern.
 
Initially, the bass of the RE-400's seemed far too anemic and lacking, especially the sub-bass. I expected this and waited to burn them in for about 50-100 hours before deciding my feelings on the bass. After burning them in and getting used to the sound signature, bass seemed much more present than beforehand and even though I still feel there is a lack of sub-bass, I'm pleased. Bass overall is well extended (perhaps even more than my HD598!) and is tight and fast, which I appreciate.
 
The soundstage on the RE-400's is slightly better than what I expected pretty much at the price point and the design and it does seem reasonably wide and tall enough. Curiously enough, the soundstage seems to be slightly angled. I don't know if I'm imagining this but it really does seem to be angled and it sounds a bit more 3-D than what I expected from these. 
 
In short, the RE-400's sound wonderful with a warm, sweet neutral sound signature and a satisfactory soundstage. Though I have minor problems with the treble, mids and the bass, this is due more to the fact I prefer a slightly more colored presentation and so these are really good all-rounder portable IEMs at this price especially. The RE-400's are great all-rounders but if you are looking for a headphone/IEM that can deal with more electronic and hip hop music of that sort, you're better off looking for something else.
 
Value:
 
To conclude, the RE-400's are most definitely worth the $99 price tag. These don't require an amp but it does benefit a bit from amping if you wish from my own experience. More to the point, these are a great value and it does seem like HifiMAN has made a new waterline for the $99 IEM. These hit a rare balance in sound, good overall balance and detail yet pleasantly warm with an angled soundstage. Companies will be surely trying for years before they succeed in producing an IEM equal or better to the RE-400's. Right now these are only $99, a price that HifiMAN could've made $199 and costumers would still be satisfied. 
 
 
Albums Used:
 
Belle and Sebastion- If You're Feeling Sinister
Daft Punk- Discovery
Jeff Buckley- Grace
Living Stereo: Bruch Violin Concerto No.1; Scottish Fantasy & Vieuxtemps: Violin Concerto No. 5
Nirvana- In Utero
Radiohead- In Rainbows
Wilco- Yankee Hotel Foxtrot

Arrived in a very elegant package, this "waterline" labeled RE-400 model looked very sharp. Just like with HM700/RE-400B, a lot of attention was paid to presentation of the product to the point where they actually had to include the storage hard zippered case with extra eartips in a separate bag so it doesn't interfere with a slim profile of the original RE-400 package. The headphones were sitting inside of a felt lined foam insert with cutouts for extra eartips. Furthermore, more eartips were included with a storage case. When it comes to accessories, HiFiMAN never disappoints. In addition to headphones and storage case, they included 3 pairs of bi-flange eartips, 2 pairs of smaller black silicon tips, 3 custom shape clear silicone tips, 2 pairs of T-400 Comply premium foam tips (large and medium size), 5 pairs of filters, and a shirt clip. Though I can tell you ahead these headphones sound amazing, the right selection of eartips is VERY important to bring out the best in sound and isolation. I have a rather large ear canal and always use the largest included tip, where the custom shaped clear one provided the best passive noise isolation I ever experienced with any of in-ears.

The first thing you notice when you take these headphones out - how super lightweight and compact they are. The barrel of these earpieces is made out of lightweight aluminum material and has a great ergonomics to fit comfortably inside of your ear. The barrel opening is covered by a cloth material filter (5 replacement pairs included), and right next to the strain relief there is a pinhole port for sound shaping. Followed by a decent strain relief the cables use a durable shiny rubber coating up until the y-splitter. Included chin slider moves very smoothly and made out of the same aluminum material. After y-splitter, the cable has a "shoe lace" type of cloth material cover which is still very durable and doesn't have that annoying springy effect found with so many other cables. The cable is terminated by a gold plated 3.5mm angled connector with a flexible strain relief. I also noticed microphonics effect was down to minimum.

When it comes to sound quality, RE-400 delivers amazing results! This single dynamic driver in-ear really focuses to deliver a neutral transparent sound but unlike other neutral headphones that sound lifeless - these are very smooth and warm. The sound is not in your face, it's a few steps back, but it sounds very natural without any artificial enhancement. The characteristics that surprised me the most was the low end where neutral headphones usually try hard to show details but lack the extension. Here, you still get a very detailed bass sound without any humps, but it actually extends beyond mid-bass punch down to some sub-bass texture. It's not enhanced or boosted, just perfect to enjoy your low frequencies, well controlled without spilling into mids. I found bass to be not as fast in comparison to my other headphones, but it's very well rounded and full. Mids are very detailed, clear, maybe a bit forward but not too much. The vocals sound very natural and lush. High frequency (treble) is extended, detailed, bright but not harsh and without any hint of sibilance. Upper mids/treble is very well controlled and just perfect for extended listening period without ear fatigue. The soundstage is average, not too wide which was definitely a step back from RE-400B balanced version that had an amazing 3D width. But this is in-line with other similar IEMs, while balanced wiring/architecture is intended to widen the sound. The headphones were really easy to drive from my phone and X5, but I did notice I had to dial in a higher volume level to enjoy them more.

Overall, I knew that I will not be disappointed with RE-400, and my testing just solidified that! No matter what genre of music you are listening to, these headphones will guarantee to bring out the best in every song. The sound has just a perfect balance of neutral natural tones without going into any extreme. Perhaps if you are a basshead craving for a more bass impact or need an analytical bright set of headphones - these might not be your cup of tea. But as all around headphones that sounds and looks great, and has a very reasonable pricing in comparison to other single and multi-driver IEMs in the sound sound category - these deserve a serious consideration.
 
Here are the pictures.
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I got these as a backup to my RE-262.  I wanted something I could run without an amp.  The 400 provides that refined HiFiMan sound I have come to admire.  The 400 absolutely squares up with my 262 when amped, but I really got them so I could run lighter (just a dap), they totally impress in this regard.
I think I may be the only one that really liked the twist-to-lock fit of the 262, they just work perfectly for me.  Moving around I loose the seal on the 400 a bit too easily, but there was a generous helping of tips to play with including comply which I have never tried.  I am quickly becoming a comply convert.
 
Phone + amp + dap too much for your pockets?  Need to simplify?  this may be the solution.  It works for me, I don't mind leaving the amp behind any more.  The RE-400 fills the void until I can plug into a full size rig. 
For a Benjamin the cost to quality balance on these is stone solid.  They look great, sound great, and anything can play them.  Build quality looks like a nice step up from previous generations of HiFiMan portable gear too.
 
A word of caution:
While any flea-powered source can drive these, this is a high quality IEM, they will reveal how horrible music sounds on your phone...regardless of encoding, regardless of make.  You can listen to your phone with the RE-400, but to hear them you still need a decent dap (sansa clip is disposable at $40 and still sounds about 1000x better than your phone...ok, maybe 100x better than the htc one).

Full review here: http://www.head-fi.org/t/666851/review-hifiman-re-400-waterline-the-next-step

Sound:

The RE-400 is quite easy to drive, but not the easiest. Better than the 64ohm RE-0, but like other 32ohm phones I owned, these need some extra volume to sound better and a bit more to shine. No amping is needed, though.
 
The new RE-400 is not just an improvement in design, fit and isolation but especially in sound.
The overall sound is neutral with a small added amount of warmth, which gives a fuller sound and better balance through the whole frequencies. Nothing is overpowered, nothing is missing.
 
Starting from the low-end.
These are NOT for bassheads or for anyone looking for an explosive, earth shattering Bass. But what the new Hifiman offer is a much fuller low end from mid-bass to sub-bass that the previous models were really lacking. While they lack in impact, they still manage to give quite a rumble.
As for the bass quality, it's what you'd expect from Hifiman, SUPERB. Quick, very tight and accurate. You can hear (and feel) every beat, every punch and every kick. Just amazing. Quite fast, but still not the fastest. The ATH-CKN70, for example, showed a much higher speed (well, those aren't just a simple dynamic driver earphones).
 
Jumping to the high-end. Treble has a good extension with some extra brightness, but remains smooth and non-fatiguing even at a higher volume. While it may not have the 'endless' extension as the RE-0 (it may be closer to the ZERO), it is full, energetic. There's a lot of micro detail as well, not unlike as its predecessors. 
 
And, finally, the midrange. Now, this might be the best part of the RE-400. Just BEAUTIFUL! As simple as that.
As stated before the whole sound is very neutral, but the mids are sweet and just slightly forward, but not thick enough to fall in the mid-centered group. Everything sounds very natural, detailed, transparent and open. Nothing recessed or missing, but the opposite, immersive and addictive. So effortless!
When it comes to more complex music, the RE-400 handles everything with ease, rivaling, and even beating, some good Balanced Armature IEMs.
 
Vocals need a special mention here as they're even a bit more forward than the rest of the sound. Also, vocals need a bit more time to 'break-in', as they can sound a bit weird (unnatural) and not well-positioned at first. After that, they sound as great as vocals can sound. Every word, every letter can be heard, be it with male or female, main singers or backgrounds.
 
Soundstage is not too wide, deep or high, but the whole sound has a fair 3D effect.
 
 
EXTRA:
As I wrote above, I found the small bi-flanges to provide the best sound out of the RE-400, so everything up to now is based on that setup.
Now, I'd like to mention some differences noticed when using the Big Bi-flanges.
When switching to the larger, wider bore tips the sound change as well.
On the whole, the sound remains similar, which is open and detailed, but the presentation is a bit different. The bass has some bigger and deeper impact, but is also not as tight as before. The highs are brighter and extend even further.
But what suffers the more is the midrange, sounding less forward and less sweet, but on the whole is has a better balance.
 
[And for those who find the stock big tips too big, some aftermarket eartips can give a similar effect]
 
In either configuration the RE-400 is very versatile when it comes to music genres. They don't excel in something particular, but don't lack either.
Still, those who listen to electronic, EDM, trance/techno and similar music may want to look somewhere else.
 
In short, one of the best All-arounder IEM, very detailed (but not analytical), airy, well layered, immersive and engaging sound.

Packaging and build: 
The packaging is minimal and exquisitely so. The extra tips filters and manual are behind the felt coated foam holding the earphones. As I gingerly dislodged them from the grooves, I was struck by how tiny they are. I always try to avoid gripping the strain relief as a precaution, but it was difficult considering the size. The shiny bead blasted aluminium back goes well with the brushed aluminium housing. Which brings me to the build. This is the most common qualm people have reported. The plug is beefy, the y split seems sturdy enough. However, I noticed that some free movement of the cable is possible at the entry point of the strain relief. As long as the cable is secured properly within the main housing this shouldn't be an issue. (I was tempted to add a dab of glue at the strain relief end to restrict that free movement).
The half and half cable is… okay. The cloth half is a little kinky (pun not intended). The sticky half is thin and flexible making it very comfortable when worn over ear. Apparently, the hybrid design serves to reduce weight among other benefits.
 
Accessories, Comfort and Isolation:
Tips galore but an odd assortment. Anyway, I have very narrow ear canals and the smaller tips gave me a good seal. The pseudo-double bump tips gave me pressure problems, so I settled for the bar-tips. The complys are good, but the foam overhangs (ahead of the rubber tube) get scrunched. (I have modified them by cutting off the overhangs) Cable noise is more than present when worn cable-down. Almost disappears when worn over-ear. Can hardly feel then in my ears after a while. It is evident that the HiFiman team has paid a lot of attention to ergonomics. Other accessories include a shirt clip, 5 pairs of stock filters. I have dry wax so I won’t be changing them out anytime soon. Perhaps I could use them to hard EQ them (doubling the filters, felt mod etc.) Maybe later.
Isolation is average, even with a good fit. But maybe that’s about as good as it gets for vented earphones. The vent is placed ventrally and only the deepest fit might shield it partially.
 
Sound:
A short intro/disclaimer My experience when it comes to iems is very limited. The RE400 is my first foray into audiophile territory. I’ve been in a V/U-shaped bassy world thus far. 
Chronologically....Sony MDR-E818LP>Sony MDR-EX35LP>Creative EP-630>Xears TD4 Ebony Blackwood>Brainwavz R1>HiFiman RE-400
I’ve loved and hated every set. So I set my sights higher and decided to bravely plunge into a neutral world just to see if that was the right direction for me.
Doing an A:B comparison doesn't make much sense with iems that differ this widely.
My impressions may seem overblown to some. But such a drastic change in direction can do that. Back to the review I expected to be disappointed by the RE-400 in the bass department. I like a little rumble and feel in my bass. But given my inexperience, I was very curious about bass quality vs quantity.
 
Fast forward to my impressions… I initially thought of describing it by music genre. But after a week with them, I’ve decided to go ahead with the classic break-up.
 
Treble:
I’ve always found sharp treble to be off-putting. There is a (false?) sense of enhanced clarity that comes with sparkly treble. But for me, the overall enjoyability dips. I’m absolutely amazed by how smooth the treble is on the RE-400. Some may like a little more sparkle, its sooo perfectly where I want it to be. It may lack some bite with fast electronic music. I found no nasty peaks or dips. To me, the detail and clarity was eye widening (considering my experience or lack thereof).
 
Mids: 
I was expecting to be impressed. But not blindsided like this. It felt like I had suddenly switched from 192kbps to a vinyl track. The first thing that struck me was how much more life-like it felt. The vocals had a certain texture. Simply put, if that texture was absent, the vocals wouldn't be as immersive. A striking feature was the depth to the vocals (not necessarily to the soundstage). It sounded “wholesome”(male and female alike). I’m finding this very hard to describe but I must persist, because it’s that important. I am able to gauge how much breath and effort the singer is taking. Apart from the core vocals I hear a lot of nuances and details that contribute to that sense of “completion”. This particular feature impressed me the most in this iem. Another thing I noticed is how untouched and unaffected the mids are. No matter how busy rest of the spectrum gets, the mids always come through unadulterated. Like I had a separate pair of ears for the mids. And it seemed like the bass and highs complemented it nicely. Like they were all on the same plane of preference.
 
Bass: 
I will have to divide this segment into two. Initial impressions and Brain-burnt–in impressions.
Initial: Sub-bass felt non-existent. Some tracks need that sub-bass to sound right. It adds to the ‘natural, warm’ feeling. Sub-bass is more ‘feeling’ than ‘hearing’. Tracks that had a strong mid-bass component were handled beautifully. I couldn’t believe the detail and how fast it sounded. But I would have liked some more punch. Sadly the mids keep grabbing the spotlight therefore I didn’t get to try many bass heavy tracks.
Brain-burnt in: Sub-bass still felt weak. I do see they measure near flat through the bass, but they could do with more presence in the sub-bass. I did find out at higher listening volumes, that the RE-400 extends pretty deep. I feel the punch in the mid-bass now(I think it feels more apparent when you get accustomed to the signature). I find the quantity sufficient(not lacking) now. Surprisingly enough, I’m actually enjoying them immensely. I love the attack speed and the detail, even when it gets busy. I want to say “resolving” but I’m not sure if it is the correct term. I’m quite stunned to find myself enjoying this “type” of bass. The initial disappointment only surfaces when I find the sub-bass lacking. ljokerl advised me to try a “narrow” lift of a few dB in the sub-bass. This improves presence without affecting the mid-bass or the mids. The RE-400 is a very capable iem in this respect. The overall tonality has warmed and I’m not disappointed as often. I still find myself wanting a bit more presence but I don’t think EQing it in is the answer. (Perhaps a vent redesign, dampers coupled with a sub-bass lift). Drums sound very natural (except the deepest reaching ones). It’s easy to differentiate between the types of drums. The bass conveys that much detail.
Bottom line: Bass enjoyment is very track subjective. EQing helps because the drivers are capable
Extra tip: The EQ in Poweramp for Android (with the DVC audio setting enabled) is very effective in boosting the sub-bass without "upsetting the tonal balance"
Other miscellaneous rambling:
The soundstage isn't the widest. The Brainwavz R1 has spoiled me in this regard. But it isn’t congested either. It conveys a good sense of space. Vocals can be very very intimate. And orchestras can be sufficiently spacious. No complaints there. All the music components are clearly positioned and layered without any interference. I believe that is good “imaging”?
 
Like I mentioned before, I sense an overall “completion” in the music. Vocals will have a ‘bass’ component and a ‘lower highs’ component in addition to the core “mid” component. The RE-400 delivers all of it in equal measure (just a tad more in the mids). I have observed that they sound even better at higher volumes (+1/2 dB above normal listening volume).
 
I am curious to as to how the RE-400 will perform when powered by a better source. That will have to wait as I don’t have the resources
 
Some have reported good results by using dampers to add a little warmth and presence (even going as far to comparing it to the 400$ RE-600). I will try these mods later on.
 
Conclusion: This iem was meant to be a test, an experiment. My first foray into neutral audiophile territory. And they have surprised me. They have made me second guess my sound sig preference. I know what I want now (until the next revelation). But what I want now is so different from what I wanted, I doubt I’ll ever have such a drastic change of heart.
I expected it to fit a small segment of my music but I’m shocked at the versatility and satisfaction it has given me in most of my music.
 
I have a very non-technical way of knowing when music sounds really good to me. It has nothing to do with genre, mood or content. It depends solely on raw music quality. This happens to me with “certain tracks” that span a wide genre(Examples: Imogen Heap- Let go, Jasmine Thompson - Home, Mick MCauley & Winifred Horan - A Daisy in December, Eminem- Sing for the moment etc). Well….. My eyes well up. Not related to feelings of sadness, happiness etc. My eyes simply leak a lot of tears without warning(freaked me out the first time). Let’s just say, I can’t see through the haze of tears when I have the RE-400 on. It’s only happened with the Fidelio L1, some active speaker I can’t remember, rarely with the Brainwavz R1.
 
The RE-400s have set the bar very high for me. If these had a more sub-bass presence I would have absolutely nothing to complain about. I think finding something much better will be very difficult unless I burn my wallet, so I will now look for an iem to complement (not beat) the RE-400.
 
Credits:
@esantosh for all the advice he’s given me. And for replying to my monotonous PMs.
@modulor, @Tom22 for their detailed and comforting words from a very understanding POV.
Big ups to HiFinage for bringing HiFiman to India.
 
Edit: I have rephrased by impressions of the sub-bass. It is my first review, and a year and a lot more experience later, I do feel my wording was not an accurate representation of what I felt regarding the sub-bass.
HiFiMAN has now reduced the price to 79$. The 100$ market is very competitive and the new price gives it even better value.

Along with the summary below, I have posted a Youtube video review of the RE-400. If you like the video, check out my channel for more reviews
 

 
Summary
 
BUILD
 
The RE-400 has a sensible, well thought out design. Of special note is the half-rubber / fabric cord which cuts down on microphonics. The RE-400 is comfortable to wear with cable up and the metal earpieces seem quite durable. However I find the plug to be overly large and can be difficult to accomodate in some pockets. The included accessory selection is quite poor, with only a few tip sizes included. Unfortunately I could not get a good seal with any of the tips and ended up using Sony hybrids, so please bear this in mind when reading the following sound impressions.
 
SOUND
 
The RE-400 has a neutral, smooth sound with perhaps a slight emphasis on the lower mid-bass, though this is certainly no bass head earphone. Everything is very tight, very fast and this is truly an amazing performer - not even considering the price at this point. Soundstage is not immediately very wide however, and people after something with a wider soundstage should perhaps look at the Sony MDR 7550.
 
Overall
 
I think despite the small issues I have with the RE-400, it offers absolutely stunning value at the $99 price point and really lays down a challenge to other manufacturers. As a neutral IEM the RE-400 stands shoulder to shoulder with other good dynamic options like the VSonic GR07 and Sony 7550, and does it at a lower price and better ergonomics. I absolutely applaud HiFiMan for the sharp pricing on the RE-400 and would heartily recommend it to almost anyone.

I ordered these when my Astrotec AM-90s finally bit the bullet. Liking them so far, however the Left side is cutting out possibly due to a short on the plug.
 
Messaged HiFiMan and hope I get a replacement. I would had given a 5/5, but I'm knocking off 1 1/2 stars due to the durability problem.
 
I hope its just this one and it doesn't happen on the replacement.

Basically, these IEMs blow away the cheaper stuff I've owned (CX300-II, MH1C). They really make a slew of genres and tracks sing with great presence and detail without a "harsh" sound or sibilance.
 
Coming from bass-heavy IEMs, they definitely lack sub-bass. But for most genres it's not an issue. And for the most part, the E11 amp (EQ bass boost option) can kick that up to where it's needed when it's needed.
 
Also of note, apparently Head-Direct is sending a carrying case now (I received a zip, clamshell hard case).

 
Thanks to the folks at HiFiMan for sending me a sample of their latest IEM to review.

Introduction

Around here, HiFiMan needs no introduction. I first learned of them in early 2010, back when they were known as Head-Direct (which is still the name of their web store) and I purchased the RE0 after my faithful V-Moda Bass-Freq IEMs gave up the ghost and reading impressions on Head-Fi. Since then I’ve been a fan and I’ve reviewed a few of their products over the past three years. So, when the RE-400 was released, I was pretty excited to give them a listen. So, does the RE-400 have what it takes to carry on the HiFiMan legacy? Read on to find out.
 
Packaging and Accessories: The packaging is comprised of a long, rectangular black box with a translucent plastic outer sheath covering the IEMs, nestled within a thick foam insert. Accessories include four pairs of silicone tips ranging from a simple single flange set to two sets of new biflange tips and familiar black large biflange tips, similar to those included with previous models. Also included is a white rubbery cable winder, a bit of a superfluous accessory in my book, one that I would rather have seen omitted in favor of a proper carrying case.
 
Design and Build Quality: The metal housings are made of anodized aluminum with familiar long strain reliefs exiting the silver housings into a plasticky black cable that joins at the y-split and is from there sheathed in black nylon and terminates in a beefy and well relieved 45 degree L plug. I’m not a fan of the nylon sheathing as it makes the cable quite noisy and prone to distracting microphonics but on the whole, the IEM seems well constructed.
 
Comfort and Isolation: Being fairly small straight barrel dynamics, isolation is about average but long term comfort was quite good. As mentioned above, the RE-400 is annoyingly prone to microphonic noise but this issue can be mitigated (for the most part) by wearing them over the ear.
 

Sound Quality

Given my experience with so many of HiFiMan’s back catalog of IEMs, I had a general idea of the type of sound signature to expect from the RE-400 and actually listening to them didn’t surprise me much in that regard. The RE-400s focus on neutrality, offering a mostly uncolored and nearly ruler flat audio presentation. But unlike its forebears, the RE0, it lacks the thinness present in that ‘phone. But let’s start at the bottom and work our way up, shall we?
 
The low end response is different from other HiFiMan IEMs in that it’s…well…present. Now don’t go thinking that this is the sort of bass that’ll shake your eardrums because it’s not but it possesses more body and texture and a bit more depth than the RE0 and RE-ZERO could muster. They have the ability to reach very low, with little discernible roll off even down to 20 Hz. Because of this, it has enough grunt that I’m not left wanting more.
 
The midrange is smooth and, though a bit dry like its precursors (RE-262 exempted), is more liquid and detail rich than either the RE0 or the RE-ZERO. Detail retrieval is excellent and they’re remarkably transparent but I’m impressed more by the spaciousness of the sound. Though the soundstage itself isn’t especially large in comparison to, say the Triple.Fi 10 or the RE-262, it is larger than average and separation within the stage, not to mention stereo imaging, is great.
 
 
Treble is right in line with every other frequency in the spectrum in that it is neither forward nor recessed. It’s quite linear and airy, detailed and clear. There’s plenty of sparkle and shimmer without sounding overly metallic and sibilance is non-existent. Top end extension is fantastic, rivaling the RE-ZERO and giving the omnipresent treble of the RE0 a clear run for its money.
 
The result is a tonally neutral, linear presentation that is absolutely phenomenal. Yeah, I know this sounds like hyperbole but it isn’t. It has certain seductive qualities that belie its true abilities, luring you in with its completely inoffensive sound signature and allowing the detail to sink in rather than shoving it in your face the way the Rock-It Sounds R-50 does. The RE-400 doesn’t try to impress with aggressive detailing or a presentation that errs on one side of neutral or another or emphasize one frequency range (mids, treble, bass) at the expense of the others. But, oddly enough, it’s because the RE-400 doesn’t try to sound great that it actually does. This is one of the few IEMs in my collection I’d truly say sounds “effortless”. It doesn’t try to sound as good as it does, it just…does.
 
One issue I have to note is that they’re perhaps a bit too polite in their resolution of tracks. They aren’t as unforgiving as the R-50 and are generally quite smooth in that regard. Personally, I didn’t find this to be an issue because it isn’t really a knock against their overall sound quality.
 

Conclusion

The HiFiMan RE-400 is available from head-direct.com for $99 and at that price, they are highly competitive. At $50 cheaper than the now discontinued RE-262 and $20 cheaper than the R-50 but competitive with both of those earphones in terms of pure technical ability, I’d say they’re quite the steal. Overall, I’d say they’re clearly better than the outgoing RE0 and ZERO and within striking distance, if not on the same level, of the best earphones I’ve heard.
 
It goes without saying that I like the RE-400 quite a bit. The neutral sound signature might not appeal to everyone and likely won’t be the best fit for more mainstream oriented listeners but those who value tonal accuracy and transparency should give these a look. These face stiff competition from other relatively inexpensive IEMs like the Rock-It Sounds R-50 and VSONIC GR07 (the latter I haven’t heard, just going by impressions I’ve read) but HiFiMan’s combination of low price and high performance should be more than enough to help them compete.
 
So, yes, I’m positively enamored with the RE-400. It reminds me of my first days of owning the RE0, how they wowed me with sound quality like I’d never before heard. While the RE-400 comes at a time in which I have a great deal of experience with high end earphones, it still had the chops to impress. I guess you could say things have come full circle.

 
 

1. Driver: 8.5mm Dynamic-Driver​
2. Impedance: 32 Ohm +/- 3.2​
3. Sensitivity: 102dB/1mW​
4. Frequency Response: 15 – 22 kHz​
5. Plug Type: 3.5mm Gold-Plated
6. Cable Length: 1.2m​

 
 
Packaging- the RE-400's packaging consists of two layers; the first one being some kind of a black translucent plastic case, which has the RE-400's main-features written on its front. The left packaging layer is a black-cardboard box;
 
 
 
 
the RE-400s are placed on a velvet-like surface on this layer's top, in a presentation that resembles jewelry presentation. On the other side of this velvet-like surface we can find the included accessories. You can watch me unboxing the RE-400s on my new YouTube channel here.
 
 
Accessories- you do not get a great amount of accessories with the RE-400s. The included accessories are:
 
Four pairs of ear-tips- HiFiMan includes four pairs of silicone ear-tips, which I've found to be of a quite good quality and well designed. We get two pairs of medium-sized bi-flanges, a pair of single-flanges and another pair of VERY-large bi-flanges. The single flanges have a silicone-splitter in the middle of their bore, a thing which I don't know the purpose of, but I do have a guess, which is that it might be there in order to put some filters inside the tips (because some companies have already done some similar things in the past).
 
 
Cable Winder- HiFiMan also includes a white silicone-made cable-winder, which you can wrap the earphones' cable around. I've tried to wrap the cable around it, but any time I did so, the cable slipped out of it after a few minutes.
 
 
The lack of a case is very noticeable, because now, even most of the $50 IEMs are provided with a one, so a $99 one should have a one included too in my opinion. I would've preferred to get a case instead of the not really helpful cable-winder. As for the ear-tips, I'm quite happy with them as they come in three different shapes, which means that fit most-probably won't be a problem.
 
 
Building Quality & Design- The RE-400's design is focused on the functionality and usability rather than of their look; it is a very low-profile and not-flashy one, and no one is going stare at you when wearing these. The small housings are fully metal-made; their body is chrome/silver colored and their back is covered with a small shiny metal plate, which is scratch prone; this part on both of the earpieces of my RE-400s is already quite scratched. The housings feel solidly-constructed and built with durability in mind.
 
 
They are vented in their bottom side. The nozzles are on the shorter side, but the tips do not stay in your ear, like it happens with many short nozzle'd IEMs.
 
The sound-tube is covered with a protective fabric-filter, which is rather unusual (because usually, a metal or a plastic piece is used for this purpose), but I've had no problems with it so far. The cable's entry into the housing is protected with a plastic strain-relief, which is on the longer side. It is both tough and flexible in the needed levels, and it seems to protect this weak point quite well. The left and right markings are printed on the strain-reliefs in white "L" & "R" letters.
 
Similarly to what was done by T-PEOS in their H-100s (which I've also reviewed, here), also HiFiMan chose to divide the cable into two parts, each part coated with different-materials. The upper part is thinner, and is coated with rubber, while the lower part is thicker and is cloth-coated. That is done in order to make the cable produce less microphonics and also to make it more comfortable for the user, since the part that is close to him is lighter. So far, I haven't experienced any kinks in the cloth-coated part of the cable, a thing which I'm mentioning because some of the cloth-coated cables start to have some annoying kinks in them after a while, and I hope that it's not that case with the RE-400.
 
 
 
The Y-Split is an about 2 centimeters-long piece of black-plastic. It has HiFiMan's logo printed on one of its sides, while the model's name is printed on the other side, both in white letters. We also have a very low-profile cable-cinch, which is colored in the same silver color as the housings (you can see it in both photos of the Y-Split).
 
 
Comfort & Ergonomics- I remember hearing about people that were having some comfort problems with HiFiMan's former RE-262s and RE-272s. It seems that the feedback regarding to the comfort & the fit was taken seriously by the company, since the RE-400s are one of the most comfortable IEMs that I've used till now. Their housings are not only tiny and light, but ergonomically designed too, so comfort isn't a problem with these. Also, I've found the included ear-tips, and especially the Medium-sized bi-flanges to be almost a perfect fit for me. They are different than other bi-flanges, as their two flanges are closer than usual, a thing which I guess that helps with comfort. The small housings make these suitable for deep-insertion, but not as deep as Etymotic's IEMs.
 
 
The RE-400s can be worn either with the cable down or over the ear; personally, I wore these over the ear for most of the time, but it's only my personal preference, so you might prefer wearing these with the cable down.
 
Isolation & Microphonics- the fact that the RE-400 is vented doesn't make its isolation mediocre; actually, I was surprised to find that the RE-400s isolate outside noises quite well. I think that the explanation to this is that the vent is inserted relatively deep into the ear, so it doesn't really enter outside noises into the housings, and also because of the great seal that is achieved when using the included ear-tips. Due to the smart cable design (dividing it to two parts, each with a different coating), there are almost no microphonics present; the rubber-coated cable is almost silent, even when worn straight down.
 
In addition, you can always wear these over the ears, and then, the microphonics are almost fully eliminated.
 
Sound-Quality- The RE-400s were given about 150 hours of burn-in prior to beginning the critical listening; no changes were noticed after the burn-in period.
 
The gear that I have used during the reviewing process is my 4^{[size=small]th[/size]} Generation iPod Touch, which is loaded with mostly iTunes Store M4A files and 320 KBPS file. For some of the time I've listened to the RE-400s directly out of my iPod, while I've also tested it with amplification, provided by Firestone Audio's Fireye HD amp, connected to the iPod's dock input through a generic LOD to 3.5mm adapter.
 
The 8.5mm large Titanium-coated dynamic driver produces a balanced, detailed (but NOT analytical in any way), natural and neutral (with a slight bass-boost) sound-signature, with clarity and cleanness all over the place. I have heard some calling these too "polite" sounding, and even boring, a thing which I could understand in some cases, but it all depends on the sound-signature that you prefer; I do agree that these aren't the most "exciting" sounding IEMs, but I can also tell you that I enjoy listening to these quite a bit honestly. We will now move on to a more detailed description of every one of the sound's parts:
 
Bass- the RE-400's bass is on the tighter and more accurate side of things, but it is not lacking in amount by any means (though you should not expect these to be some bass monsters, as they're not) and it has a full-body with a nice presence when the track "calls it". The impact is a tad soft in my opinion, and the extension isn't so deep, but both things didn't really bother me when looking at the "full-picture, i.e., the RE-400's other technical abilities serve as a "compensation" to these disadvantages. The bass' speed is just amazing, moreover for the RE-400's $99 price-tag. Its dynamics and punch are quite good too, both which are said to be improvements over HiFiMan's older models such as the RE-0 and the RE-262 (I didn't get to hear these, but such things were mentioned by people that did get to try all of these and have compared them).
 
Midrange- the mids produced by the RE-400s are just beautiful; they feel so open, airy and natural, while being very clear, transparent and tonally balanced. Detailing is exceptionally good for their price. The details aren't "thrown" at you; they're just there, waiting for the listener to "catch" them. The timbre is done wonderfully, being so realistic and "live"-feeling, so guitars and strings sound really good with the RE-400s. I would've liked the midrange to be a bit more energetic and powerful, but that's my only real complaint about it.
 
Treble- the treble is nicely integrated with the midrange, both being in each other's line. The highs extend very nicely, and are well detailed in all of their areas, just like the mids. I have detected only a minor amount of sibilance, so there are almost no ear-piercing's' sounds that these produce, which is great. Clarity and cleanness are present in the highs too, giving the sound that kind of special transparency that is also in the RE-400's mids. Sparkle is produced in the right level, causing the cymbals to sound natural and quite real, while not being fatiguing or overly-done.
 
Sound-Staging and Instrument Separation- the sound-stage isn't as amazing as the sound's other parts. By this, I'm not trying to say that it is bad, as it's not by any means, but rather only decent. It does give the sound a nice sense of space, but I would've liked it to have a bit more depth. On the other hand, instrument separation is a really sweet surprise when looking at the $99 asking price, as the RE-400's performance in this department is comparable to many higher-priced IEMs.
 
HiFiMan brings a new standard of sound-quality to the below $100 market with the RE-400. With their sound-quality, I could've easily seen them sold for around $150 or even more. The RE-400s possess a neutral and balanced sound-signature which won't appeal to anyone, as some listeners might find it a bit light on the bass, though I'd say that most of the people that would try them would also like them. I liked the way that they sounded with every genre that I've listened to with them, so I would say that they are quite versatile; I might even call the RE-400 an all-rounder. Offering an ergonomically-designed housing and a great isolation together with an amazing sound-quality makes the RE-400 "a full package". For only $99 I couldn't recommend these more!
 
 
Where to Buy? The HiFiMan RE-400's MSRP is $99. It can be purchased for that price directly from HiFiMan's web-store, here. The RE-400s are said to start shipping to HiFiMan's dealers all over the world soon, so check out if your local dealer will have them in stock.
 
I'd like to thank Peter for the review sample.
 
This review was reposted from my audio reviews & news website "It's A Headphones Thing". Check it out for some more IEMs and Headphones reviews, here. http://iahpt.wordpress.com/

 

 
 
 
[size=small]HiFiMAN needs no introduction around here, so I'll simply share my opinion briefly. In my mind, not only are they one of the premier manufacturers of headphones and related gear, but - and this is possibly more important - they deserve a lot of credit for helping advance the headphone industry in general. Of course, they aren't alone in this category. Plenty of others have done amazing things over the last few years. But I can't think of anyone who even approaches the broad portfolio of HiFiMAN. They have gear competing for best-in-class in a variety of categories - their HE series of planar magnetic headphones, their RE series of IEMs, their EF series desktop amps, their HM series of portable players... all that remains is a dedicated DAC or two to completely cover the full range of HeadFi hear. [/size]
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[size=small] I've reviewed the HE-400 headphones and loved them. I also use the HE-500 and those are great too. But this is my first time actually having a HiFiMAN IEM of my own. I've heard some of the older models like the classic RE-0 and RE-ZERO, as well as the more recent RE-262, but never got to know them well enough to really form a solid opinion other than "they seem good". HiFiMAN contacted me and asked if I'd like to review their newRE-400 Waterline IEM ($99). Since I write for InnerFidelity as well and have plenty of reviews on deck, I wasn't sure if I would have time for this one. But I decided to work it in and boy am I glad I did. [/size]
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[size=small] DESIGN[/size]
[size=small] Like all the prior RE models, RE-400 uses a dynamic driver. In this case HiFiMAN uses an advanced 8.5mm unit with a titanium driver. Impedance is rated at 32 ohm, sensitivity 102dB/1mW, max power 30mW. So don't try running this on HiFiMAN's powerful EF6 amp as it probably won't be ideal....[/size]
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[size=small] The cable is made from OFC copper and has a cloth sleeve leading from the 3.5mm, semi-angled plug to the Y split. From there it uses a soft rubber material leading to the earpieces themselves. I speculate this section was left "unsleeved" to minimize microphonics. It feels kind of flimsy but also strong at the same time and very flexible which is a good thing. Having been in the IEM game for a few years now, I'm sure HiFiMAN knows what they are doing with respect to making sure cables are appropriately durable. Bonus points are awarded for the slider which appears to match the silver shells of the IEMs. [/size]
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[size=small] The IEM body itself is made from a metallic substance (aluminum?) and feels durable yet lightweight. There's a very small port on the bottom of each earpiece which is fairly common for dynamic based designs. Isolation doesn't seem to suffer - while these are no Etymotic ER4s, they do have moderate isolation as could be expected from a design like this that seems designed for medium insertion. I can get them to go in rather deep if forced but the sound gets worse - I don't think they were intended to be used in that way. [/size]
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[size=small] Looking at the pictures, or even seeing them in person, these don't seem like tiny IEMs. The Ultimate Ears UE700 or the Jays Q-jays are the two smallest models I can think of, and the RE-400 doesn't strike me as being in the same category with regards to size. Even so, it's definitely on the small side, and real life shows them to be smaller than I had expected. Even with medium insertion the shell nearly disappears into my ear and is hardly visible from the outside. This makes the RE-400 one of the few IEMs to be suitable for listening while laying down. [/size]
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[size=small] The RE-400 comes with a rather nice assortment of tips - think quality over quantity. I got good results with the typical medium sized single flange tip. But I got even better results from the medium biflange tips. I don't normally get along very well when it comes to dual or triple flange tips so I was surprised at this. These tips have each "layer" closer together than most biflages, and the insertion is barely deeper than the basic single flange tip, so perhaps that's why it works so well for me. [/size]
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[size=small] GEAR[/size]
[size=small] I listened to the RE-400 on a variety of equipment including:[/size]
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[size=small] Sansa Clip+[/size]
[size=small] Meizu MX 4-Core[/size]
[size=small] iHiFi 960[/size]
[size=small] HiFi E.T. MA9[/size]
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[size=small] I also used my big home setup based around an Auraliti PK90 player and a Resonessence Labs Invicta DAC/amp. The RE-400 hits the "sweet spot" of usability - it doesn't sound terrible on a basic player, but does scale reasonably well as your source and amplification improves. I appreciate this as some of my IEMs sound miserable on a basic DAP, and others top off too quickly. The RE-400 seems to have something for everyone. [/size]
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[size=small] LISTENING[/size]
[size=small] The first thing that struck me about the RE-400 was the clarity. It's got a very clean, accurate presentation which defies any attempt to stereotype IEMs based on a "dynamic driver sound". If I believed the stereotypes, I would probably think this was an armature design but that just isn't the case. If you think all dynamic IEMs have thumping bass and somewhat slow or muffled highs, you obviously haven't heard enough of them to know better (and specifically, you haven't heard anything in the RE-series).[/size]
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[size=small] The overall sound falls slightly onto the analytical side. It doesn't go as far as something like an Etymotic, but it does tend towards neutrality and precision rather than relaxed fun. Bass doesn't thunder but what's there is tight and accurate. I find that most of the time it is plenty satisfying for me - any type of rock or jazz, or practically any music using real drums, sounds very nice. Only when trying some hip-hop and electronic music where exaggerated bass is the focus, does the RE-400 seem occasionally lacking. What's there is great - there just sometimes isn't enough of it to rattle your ears in the way you might want. Again, this is a tuning choice rather than a deficiency, and the RE-400 joins the Sennheiser HD800, AKG K701, and many other models with deliberately non-bass-heavy sound signatures. But I don't want to make it sound too bass light - the RE-400 is plenty satisfying for me in all but a few cases. [/size]
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[size=small] Mids on the RE-400 are really the star of the whole show. Open, clear, and very transparent, they carry the listener further into the music than any $99 headphone has a right to. Vocals sound clear and lifelike. Snare drums have appropriate snap. Everything sounds "real" for lack of a better word. It's quite intoxicating, and forces me to cast an accusatory glace at some of my other (more expensive) IEMs like the $399 Westone AC2. The AC2 has some great bass but could definitely learn a thing or two from the RE-400 in terms of midrange transparency. [/size]
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[size=small] Because of this excellent midrange, the RE-400 works well with "audiophile" grade recordings. I had a great time listening to Marta Gomez - Cantos De Agua Dulce, Livingston Taylor - Ink, Oscar Peterson Trio - Night Train, and a boatload of classical works from a variety of labels. I even tried some DSD tracks through my Resonessence Labs Invicta and they sounded stunning. I can't think of a better $99 headphone or IEM with which to listen to great recordings. [/size]
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[size=small] The top end of the RE-400 is extended and clear, but not overly sparkly. For some people this will be very welcome - hot treble is something that really bothers certain people, and can kill an otherwise great listening experience. The RE-400 is nicely balanced - fairly clean and extended without being harsh or overly emphasized. The downside is that some people might find it a little boring. I personally don't hear it this way but I can see how someone else might. If your preference is geared towards the super-exciting, you may find the RE-400 a tad bland. [/size]
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[size=small] The good part about the highs being the way they are - this is not a completely unforgiving IEM. Sure, it sounds better with quality equipment and recordings. But it rarely becomes completely unlistenable. That's not the case with some of my high-end custom IEMs which practically demand a good source. I recently listened to a flagship custom (which shall remain nameless) on a Sansa Fuze - playing Mastodon's Crack The Skye, I could only handle a few tracks before I had to turn it off. It just sounded like a blurry, harsh mess. I'm very familiar with that album on my home setup and while it isn't exactly a Steve Hoffman masterpiece, it normally sounds far less strained. So I switched to the RE-400 and bingo! I could actually enjoy the music once more. There's a headline in there somewhere: "Extra! Extra! HiFiMAN RE-400 superior to $1,000+ 6 driver CIEM! Read all about it!" This is deceiving of course, because switch to a better source and that flagship custom completely dominates the RE-400 - as it should for the price. But what I'm getting at is this: the RE-400 is not overly analytical and actually does a great job with average quality sources. [/size]
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[size=small] CONCLUSION[/size]
[size=small] I'll keep this fairly simple - the RE-400 is not a massive deviation from the earlier RE-series models. I'd call it more of an evolution than a revolution. It hasn't turned into a bass monster, nor has it gone completely ER-4S all over the place. Still, in some ways it does seem to have developed a more "universal" sound. I suspect the even response and clean sound will work for more people, though a few who previously loved the RE-0 might find RE-400 too homogenized for their taste.[/size]
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[size=small] As far as I'm concerned, the RE-400 is about as good as it gets for $99, and then some. That includes IEMs and full sized headphones too. I can think of nothing else in the price range that has such smooth, transparent sound, and still remains engaging. Add in the quality build, excellent fit, and well-proven history of customer support, and it seems like an easy recommendation. HiFiMAN does it again![/size]