HiFiMAN RE-400

Hifiman is mostly known for their open-back planar magnetic headphones and I myself own 3 pairs. As you may already know, almost all of their headphone offerings have become benchmarks in their respective price ranges. Other than headphones, they make IEMs, digital to analog converters, amplifiers and digital music players which are more or less successful in their own right and this is a review of one such product: their bullet style IEMs RE-400.



RE-400 is their cheapest IEMs as of now and although the original price for it was 79.00 USD when it first came out, now it’s sold for 19.99 USD on their official site and Amazon.

Disclaimers​

Hifiman RE-400 was provided to me by Hifiman for free and I only paid for the customs fee. As I always say, everyone is biased one way or another so take everything you read with a grain of salt. Also I will try to be more concise and to the point in my reviews from now on without worrying about the word count etc. If you have any questions, please ask me in the comments and I will try to answer them to the best of my abilities.

Build and Accessories of Hifiman RE-400​

Shells of the RE-400 are bullet shaped and relatively small. Not as small as Final Audio E series IEMs, but still very comfortable. As materials used, they are made out of aluminum, not the smoothest aluminum out there, but still feels premium especially for the price.The cable which is fabric coated below the splitter by the way, isn’t replaceable and has some memory unfortunately. Cable termination is 3.5 mm single ended and angled.



RE-400 comes in a compact plexiglass packaging. It doesn’t look too cheap and they probably decided to increase the contents along the way since there is also a bag of accessories that comes with it. Apart from the IEMs, you get a carrying case and 8 pairs of different eartips. I mostly used double flanged ones in my testing.

Sound of Hifiman RE-400​

Tonality​

RE-400 has a neutral tuning, almost like an average Etymotic. It isn’t particularly devoid of bass but there is not too much of it to speak of. As a character, the bass is relatively fast and tight.



Mids are very clean and clear but also a little lean. Vocals mostly keep their distance. In this sense, RE-400 kind of sounds almost like their open-back planar magnetic headphones.

There is no harshness in the treble region but it also isn’t very smooth. There are narrow peaks you notice occasionally and treble extension isn’t great either.

Technicalities​

The most impressive aspect of RE-400 is its staging capability. Stage expands sideways and it creates an interesting hall effect. In fact, it was the first thing I noticed as soon as I put them in my ears. Imaging is also pretty good.



RE-400 sounds kind of dry but other than that timbre is mostly fine, nothing jumps out as unnatural. Lack of extension kind of hampers the rendering capability but at this price, I won’t complain too much. As always comparisons shed more light to how RE-400 sounds.

Comparisons​

Hifiman RE-400 vs Final Audio E3000​

Volume Matched at 1 kHz

• E3000 is much warmer, has much more bass and subbass than RE-400. However, the E3000's bass is more pillowy. RE-400 isn’t really devoid of bass and it’s tighter.
• RE-400 is much cleaner.
• Vocals are more forward on E3000. RE-400 leaves room to breathe.
• Neither is harsh. E3000 has a better treble extension but that might also be because of the deeper insertion it provides. RE-400 rolls off earlier in the upper treble.
• RE-400 has a wide spacious sound and interesting hall effect. E3000 on the other hand, also has a very tangible staging and it feels like you are in the studio with the artists. Both have their stages expanding to the sides but RE-400 is wider. Imaging is very precise on both.
• Personally I find overly warm iems suffocating. On that note RE-400 feels fresher for me.
• Both have decent timbral qualities but RE-400’s timbre is more lifelike. E3000 warmth skews the balance a little too much.
• E3000 renders more details but warmth drowns a big part of these details so RE-400 might come as more revealing to most.

Hifiman RE-400 vs Tanchjim Tanya​

Hifiman RE-400 vs Tanchjim Tanya​

Volume Matched at 500 Hz

• Tanya is V-Shaped while RE-400 is neutral. Again Tanya is warmer but it also has upper mids presence so vocals are slightly more forward. Vocals on RE-400, although not too recessed, aren’t too close and personal either.
• Bass on Tanya is also more impactful and extends deeper.
• Although Tanya is shoutier, neither is necessarily harsh.
• Treble on Tanya is noticeably better. It has good energy and is smooth at the same time; pretty much on point and it has better extension too. RE-400’s treble sounds blunted compared to Tanya’s.
• Tanya’s timbre is objectively better but I find RE-400’s timbre somewhat more agreeable. Maybe Tanya's shoutiness affects my perception.
• Tanya is more detailed by a good margin. Staging is extraordinary on RE-400. It expands wider than Tanya’s headstage but Tanya’s stage is deeper. RE-400’s imaging is also better.

Conclusion​

I wasn’t expecting too much from the Hifiman RE-400 but I was pleasantly surprised. It doesn’t set the world on fire, no, however for the price now it sells, it’s hard to make an argument against it. Especially in a market that is flooded with V-Shaped and Harman tuned IEMs, it feels fresh with its clean neutral tuning and the interesting hall effect it creates. All in all, maybe not at the full price, but for 19.99 USD, I think RE-400 deserves a place in everyone’s collection.

Hifiman-RE400 Review​

I would like to thank Mark from Hifiman for providing these IEM’s for this review

I came across this IEM maybe 10 years ago - it was then a steal at $99 for its then reference sound. But allot has happened in the IEM market in 10 years so has this ‘old dog’ still got tricks for the ‘young pups’ of the IEM market. And mostly importantly how does it sound stack up against its competition.

Original launch​

It can be funny to look back at old reviews for products that are still around, for example, here is Steve Guttenberg written Review(‘i.e. The Audiophiliac’) of the RE-400. The major complaints in this review and others from the original launch was the lack of a carrying case and a limited amount of ear tips. The price of the RE-400 at the time was $99 but unlike nearly every other bit of classic audio gear, the new RE-400 starts at an incredible $19.

Let’s see in detail how an upgraded RE-400 “waterline” stacks up - first lets have a look at what Hifiman now provides ‘in the box’:

Whats in the box:​

So looking at what we get now with the RE-400, never let it be said that Hifiman do not listen to their customers feedback as the “new” RE-400 addresses these issues mentioned above immediately once you open the box.

IEM and Cable​

While the IEM itself is tiny and cable is permanetly attached, which for $19.99 that is perfectly fine but obviously more expensive IEM’s now have detachedable cables unlike when the RE-400 was launched.

Eartips​

What I think is excellent is the sheer variety of sizes and even shapes of the ear tips provided and they have even provided some filter replacements. Different tips can have a massive effect on the sound profile and comfort of an IEM so having this variety is a massive benefit over similar priced IEMs.

Comfort​

For such a tiny IEM, the variety of eartips sizes can greatly effect the comfort. For me and my large ears, I found the largest ‘fat’ tip provided excellent seal and was very secure in my ears during a few long walks. I love how they provided angled eartips also which no doubt will suit some people.

Because it’s so small, it is incredible lightweight and mostly you can wear this for hours without any discomfort, it never feel out of my ear and it lack of weight greatly helped it stay in place compared to much larger IEM’s like the Truthear Zero (see photos later), my one issue with the comfort was the cable. I found it caused some microphonics as it rubbed again my clothes. I did change its position to around my ear which greatly helped but it is something to bear in mind.

My wife on the other hand has tiny ears she loved the size of the small tip and she has now taken the RE-400 as per favourite IEM’s for comfort and sound quality.

The difference is size can be seen in these 2 photos:

Sound quality​

So running through my long audiotext playlist - the RE-400 came across as very neutral, but does lack a little in the sub-bass region. As a sound signature, I thought it was more like the Etymotics ER2SR than the ER2XR, so bass heavy tracks like James Blake’s"Limit to your Love" didn’t have the bass punch you might expect coming from a Harman or V-Shaped IEM. But it more than made up with the with female vocal tracks - Kate Bush sounded amazing and Amy Winehouse had a liveliness that I have not often heard from IEM’s.

Midrange Clarity​

Midrange performance is exemplary, delivering vocals and instruments with a natural and lifelike presence. This midrange fidelity is a testament to the RE-400’s engineering especially looking at the size of the IEM it is hard to believe it can make such beautiful sound, appealing to audiophiles who appreciate a true-to-source experience. It actually sounds more like a Sennheiser headphone than a Hifiman.

Realistic Treble and Imaging​

High frequencies are handled with precision and without harshness, contributing to an extended and airy soundstage. This attribute makes the RE-400 particularly suitable for acoustic and vocal-centric genres.

Specs and Measurements​

The main specifications:

With measurements, due to its size this IEM especially will highly dependent ear tips and there objective measurements especially of bass and treble with vary greatly.

But I thought this might graph from Crinacle IEM comparison tools might provide a good match for what I heard from the RE-400, specifically compared to an classic Etymotic IEM:



As you can see both are incredible similar until the treble region where each manufacturer has their own unique take on treble. I personally like the RE-400 more, that boost in the 5-6Khz region provided excellent dynamics while to me was never fatiguing.

Comparisons​

Here is a comparison of the sizes of some similar priced IEM’s, the difference in size is remarkable with the Truthear Zero Red on the left, the Moondrop Chu in the middle and RE-400 on the right:

Sound quality wise the Truthear and Chu have more sub-bass both targetting that Harman curve but the RE-400 is much more balanced especially in the midrange. Basically if you want a reference IEM’s go for the Hifiman if you want a ‘fun IEM’ go for the Truthear. I would probably not recommend the Moondrop Chu due to its poor treble response, though its a similar price to the RE-400.

Summary​

The Hifiman RE-400 is a remarkable contender in the in-ear monitor market. Its focus on delivering an accurate and balanced sound profile makes it a prime choice for audiophiles on a budget. While its non-detachable cable may not appeal to everyone, its sound quality undoubtedly places it among the top performers in its price range. The RE-400 is a testament to Hifiman’s commitment to high-fidelity audio, packaged in a practical and everyday use design.

Disclaimer:​

The Hifiman RE400 were kindly sent to me by Mark of HIFIMAN, for which I thank you very much. I’m an old model (10 years of honorable service), probably in dismantling.

Nevertheless, every headset enriches my package of experience in this world.

Like all other reviews, this one will be honest and not influenced in any way.

Having received a boxless version this time, the unboxing opening will be skipped.

Hifiman RE400 Tech Specs:​

• Titanium-Coated 8.5mm drivers custom designed by HIFIMAN
• Compact size utilizing powerful Neodymium magnets
• Oxygen-Free Copper Cabling
• Advanced ergonomics for comfort and extended listening
• Stylish design and lightweight
• 3.5mm mini plug
• Mini adapter for regular earphone jack
• Frequency Response: 15Hz–22kHz
• Impedance: 32 Ω
• Sensitivity: 102 dB
• Rated: 10mW
• Weight: 0.45 oz (12.9g)

Hifiman RE400 Accessories:​

Details
From the rush to try them, I must have missed some accessory, or maybe not being a store version has some less accessory. However, included in the sale box, you will find:

• 7 pairs of tips
• Replacement filters
• A clip
• Storage for transport

For the price requested to date, the standard equipment is quite expensive! The tips are definitely weird, from very small to huge, but I have to say that among all, I found my favorites.

Hifiman RE400 Design/Build quality:​

The Hifiman RE400 stands out at first sight for its extra-small size. They are so small that they almost disappear in many people’s ears. If you do not pay attention, you may lose them in the hearing canal! I’m kidding, of course! The shell is super miniaturized and made of fine CNC aluminum, but the cable is thin. In the first, it is coated but overall very rigid and looks undurable. In my case, I have a maniacal cure, so they will last forever anyway.

Initial sound impression:​

At first hearing, they seemed very veiled and frankly did not sound very well; maybe they came from a warehouse, but after leaving them in operation for a while, the situation turned.

Their sound was definitely different, better in every way, which was surprising given their size! I was already surprised by the sound of other microdrivers that I had found in the Kbear Dumplig, but these are on a very different level.

Since they probably really came from some storage remnants, I left them burn-in for 50 hours at high volumes.

Hifiman RE400 Final sound impression:​

Equipment used for testing above:


Device:

• iMac
• Redmi Note 7 (MIUI Based)

Software:

• Foobar2000 24bit 192khz (iMac)
• Amazon music UHD 24bit 96khz (Both)

DAC:

• Hidizs S9 Pro (ESS)
• F.audio KS01 (ESS)
• EPZ TP20 (Dual Cirrus)
• Hidizs XO (Dual ESS)
• EPZ TP30 (Dual ESS)
• Lessfox DA1 (AK)

Fortunately, in the tips included in the package, I found the double flanges that fit me like a glove, isolate me perfectly, and allow me to insert them in depth.

I’m not listing the tracks because they’re too many.

My impressions are given using the original accessories.

What makes significant improvements is deep insertion, so if you can’t find tips that work for you, look for double or triple flange ones.

I would never have imagined that such quality could be achieved with such small drivers.

The Hifiman RE400 is a balanced IEM with a touch of warmth. For what they cost now, they are excellent and also incredible. The tuning is smooth as ****!

The tuning is definitely free of annoying peaks. It might be boring to some, but it’s not terribly neutral either. In the bass region, there is definitely emphasis and good speed. The voices, however, are slightly veiled, perhaps a little nasal sometimes. The musical instruments have a coherent tone, but it is their separation that is most surprising. The highs maintain a very good amount of detail without ever being sibilant or harsh.

The thing that surprised me the most, however, is the total absence of distortion, even at very high volumes. They handle the maximum volume of my DACs like nothing.

Hifiman RE400 Soundstage and Imaging:​

Keep in mind that the soundstage is enveloping in width. Imaging is really good with a precise separation. Make sure to have a deep insertion, and you can feel the magic of this tiny titanium-coated driver. I have listened to jazz, R&B, pop, EDM, and chill music.

Comparison:​

I thought I’d compare headphones that remain in the same price range. It goes without saying that the RE400 can compete in the price range at which it was released 10 years ago, even today.

vs Moondrop CHU II



The Moondrop CHU II is excellent, but the tuning is V-shaped, and the bass is very emphasized. If you are not into headphones that tend towards balancedness, then you are better off not looking at the Hifiman RE 400.

vs Tanchijm Zero and One


They have a certain resemblance to the Tanchjim Zero, but I would say that the Hifiman RE400 has a decidedly more pleasant and warm tuning. The Zeros are excellent for neutrality and detail, but their comfort has always been quite terrible. The One is slightly over budget but is worth mentioning and considering as they are also excellent. They have more pronounced bass and treble and a larger soundstage sensation.

vs Kbear Dumpling

Before trying these Hifiman RE400, they were my favorites extra small in-ears. The dumplings have a much warmer sound; the bass is dominant but also has less detail and a decidedly more nasal timbre. For about the same price, I would choose the Hifiman, but the build quality is better on the Dumpling.

Conclusion:​

At the new price at which the Hifiman RE400 is offered, it is definitely unbeatable. They have certainly gone out of production and are running out of stock. If we also consider their extra-small format, they are in an unrivaled category. If you have the chance, definitely get a pair! Not being too neutral, they adapt to every musical genre, and being so small, they fit practically every ear. A real taste of HI-FI without spending too much! The only thing they require is to be used with care due to their very weak cable, if you are clumsy you should avoid them.

​

Where to buy?

Official Hifiman Website

MatAudiophiles

HIFIMAN RE-400​

HIFIMAN RE-400
INSTAGRAM: @MATAUDIOPHILES

Prelude:
HIFIMAN probably doesn’t have to prove to anyone that he knows about headphones like few people. Of course, provided that we like well-balanced and American tuning of the headphones. This time I will take a closer look at a very interesting and quite well-known in-ear model of this manufacturer, which is the HIFIMAN RE-400, currently costing about 79 USD. I cordially invite you to read it.

Unboxing and user experience.

First of all, we have an unusual situation here, because the headphones are packed in a hard plastic box, and additionally, accessories and a hard case are included separately, unfortunately without the manufacturer’s logo. The set includes ten paper filters for headphones that allow us to tune our headphones according to preferences. We also get a large set of tips, three sets with a double collar, one set of large tips with a double collar, three quite original white tips in size s, m, l. The headphones themselves are extremely small and do not have a detachable cable. Its lower part is secured with a braid, it also has an angled 3.5mm plug. On the distributor we have the inscription HIFIMAN and the name of the model. The rest of the headphones are not braided, but thanks to this we gain comfort of wearing. The domes are microscopically small and therefore fit perfectly in virtually any ear and provide excellent isolation and fit.



Sound:
Moving on to what is equally important with comfort, i.e. the very sound of the headphones, I can safely say that the competition has something to be ashamed of.


BAS:
The low tones are fast, definitely keeping up with bass or rock arrangements. The bass is perceptible and not overwhelming, which bodes well considering the current price of the headphones, which is USD 79. In this price range, we usually have strongly emphasized bass and its low quality, of course there are exceptions to this rule, but more on that in a moment. Low tones also do not flood the whole and give a pleasant rhythm to the whole. We can not only hear them, but also feel them. They are at a nice distance which further translates into a greater sense of depth and scene.

Mids:
 The mids are slightly spaced out on the V plan, have a dark but very balanced and natural character. Vocals are engaging and show details very well, for this price range it is very good. I like the balanced and very consistent character in the midrange. Vocals don’t sound flat but inviting to listen to, smooth but not lifeless which is a great result. In addition, the midrange shows details and layers very well for this price range.

Treble:
They have been slightly dimmed, but they are promoted and consistent with the total tuning that HIFIMAN presented in the RE-400. The tuning shows the instruments great and not tiring, although they may be slightly dimmed compared to more expensive models, they are still safe and very nice for this price cap. Additionally, their purity and clarity are phenomenal. All this means that I definitely rate this model as extremely well-tuned.


Comparison:

HIFIMAN RE-400 ($79) VS iBasso IT00 ($79)

HIFIMAN RE-400 is a more V-tuned model, while iBasso in the IT00 model opted for U-shaped tuning. In the case of the IT00 we have stronger bass, a slightly closer and less linear midrange and more emphasis in the high frequencies. In addition, the RE-400 are much smaller, have smaller domes and do not have a detachable cable. However, at this price, this does not detract from their functionality.

HIFIMAN RE-400 ($79) VS AUNE E1($79)

The current price of AUNE E1 puts them close to the HE-400. The Aunes have much more top end and brighter tuning, but I personally prefer the RE-400’s natural and neutral presentation. Of course, this is a matter of completely individual preferences. Both pairs set the bar extremely high. Above their price ranges, which allows me to rate them on an equal level. If you like light tuning then choose aune e1, if darker tuning HIFIMAN RE-400 should be your favourite.

Soundstage and controls:
The sound stage focuses largely on the depth and quality of the transmitted information, the resolution is very good, but the width of the stage is average. This is not a defect, but a feature that this model is endowed with and you should just remember about it. The headphones are easy to control and do not require too much from us, which is their additional advantage. Although they really like the extra electricity and profit from it.

Summary:
The HIFIMAN RE-400, priced at $79, is a great introduction to the winding and full of surprises world of audiophiles. Well-balanced and well-balanced V-shaped headphones with excellent bass, slightly recessed, but very natural and pleasant midrange, and a gentle and balanced treble. This allows me to place this model of headphones very high, despite the lack of a detachable cable, a stage not very developed on the sides, which they make up for with depth and the amount of details. If you’re looking for a big soundstage, reach for the aune e1 or it00, but if you give it a chance, the RE-400 will reward you with great musical presentation and excellent isolation and comfort of use. These are very good and noteworthy headphones that have my full recommendation.

General/Packaging/Build/Comfort
Hifiman needs no introduction, it has already made itself well known in the audiophile community with various headphones ranging from the budget range all the way to their top of the line. Today I have with me the RE400 Waterline, which was released some time ago, i’m here to find out in today’s day and age, is it still relevant?
The packaging is very premium and not gonna discuss much about the packaging, you may refer to the pictures from Hifiman’s site.
Product Packaging Page
The only gripe I have with RE600 is the cable. It doesn’t look like it will break anytime, but it is easy to get tangled, the plus point of the cable is that it doesn’t have much microphonic noise. The IEM itself is also very light, you can go to sleep with it as well. The shell is made out of metal and the quality is on the higher side

Gears used for this review

• Earmen Angel -> Earmen ST-Amp
• iFi Go Blu
• Hidizs S9 Pro Red Copper
• Macbook Air M2 3.5 Out
• RE400 with the Large white tips

Foreword
My review is solely based on what I hear via my equipment and I never consider my reviews to be objective in any way rather a subjective approach. Do take into consideration that everyone’s ear anatomy is not the same, so the psychoacoustics perception might be different as well, but i believe it will not stray too far

Sound Impression
RE400 to my ears is neutral with a slight hint of warmth, to my ears, the low end although quantity is lacking, the note weight from the lows still carries sufficient weight/texture to it, paired with Earmen Angel, which is a reference sounding DAC/Amp, the dynamics are very impressive. The timbre sounds natural to my ears, nothing to complain about. Let’s take a look at the breakdown below:

Bass

• Bass presentation is neutral, sub bass does roll off early
• Not the star of the show, but the speed of it is very good, it handles high BPM song effortlessly
• The bass has got a slight warmth to it, giving it a pleasant texture that doesn’t sound too thin
• Mid bass has is punchy and doesn’t bleed into the mids
• This IEM is definitely not for basshead nor it is suitable to listen to EDM

Mids

• The mids are lush sounding to my ears, not recessed sounding
• Vocal for both male and female are not recessed and has good texture to it, female vocal especially (Florence+Machine), it sounds sweet and has good texture with the right energy to it
• Male vocal is not as forward as female’s, but it still retains good texture and note for male’s vocal

Treble

• Treble is smooth and plenty of details in this range
• However, there’s a slight graininess i noticed on this range
• Doesn’t sound harsh nor anywhere near sibilant
• It has got a good amount of air to not make RE400 dark sounding
• Detail retrieval is good for the asking price, considering it cost only 20$, the technical performance is actually quite respectable

Driveability

• RE400 is fairly easy to drive, but as with most micro drivers, they perform better with more power
• Pairing it with a slightly warm source, the iFi Go Blue, in my opinion is a very good pairing, the added warmth just thickens the overall note weight, a little bit more punch on the bass, with the xBass turned on, the whole experience is very positive

Comparison (RE600)

• In terms of bass, both the RE600 and RE400 sounded very close, the difference is very minor during my A/B test
• Construction wise, they are more or less the same in terms of weight, both of them are quite light, both have different cable, RE600 has better cable compared to RE400, which make sense because of the higher price
• Mids on the RE600 is slightly more forward and more detailed compared to RE400, vocal performance on both is largely similar
• Treble on the RE600 does have not have the slight graininess of RE400, detail retrieval is also better on the RE600
• Soundstage is quite similar, imaging is where RE600 takes the lead, with much better imaging
• In short, if you are tight on budget, the RE400 will do its job just fine, offering roughly 70% of RE600’s performance and fair asking price that will not break your bank

Final Thoughts
RE400 is the IEM that you don’t get the WOW effect when you first listen to them, similar to its bigger brother the RE600, it does grow on you as you spend more time with them.
Everything sounded natural and the performance of the mids is what really captivates me, having heard some other IEMs costing more than the RE400, the performance doesn’t come close except for the bass (more quantity). Released in 2013, is it still relevant today? Yes, I would say so. Recommended? Yes! If you want a no frill experience (No cable colling), prefer something neutral, look no further..

*RE400 is sent over by Hifiman for the purpose of this review. I thank them for the opportunity. At the time of writing, the RE400 is on a sale price of 20$ instead of the usual 79$, which is a steal in my opinion

Hifiman RE400 Product Page - Non Affiliated

Link to my review and measurement index thread where one can also find a full review overview, more information about myself as well as my general-ish audio and review manifesto: https://www.head-fi.org/threads/956208/


HiFiMan RE400i


Source:

Personal unit.


Miscellaneous:

Plastic packaging appears cheap, but that’s okay.
Ear tip selection doesn’t seem to follow any real pattern – while many different pairs are provided, they sometimes differ considerably in length and properties; it would have been much better and more logical to include three different sizes of tips for each type of tip. Quality and texture is good, though.

Round storage case that is simply just an unbranded case without any logo. Protective, though.

Cable feels and looks cheap; cannot really be described as flexible. Strain relief not good and no chin-slider either. Quite microphonic.
The three-button remote control has a pleasant pressure point. Although the individual keys are not so easy to recognize as such haptically, it's still quite easy to distinguish the two volume keys from the centre key due to the size of the remote control. What I don't like so much is that the remote control is located on the left side. By the way, I also doubt whether the remote control is actually mfi-certified, because on my Apple iPod Nano 7G, the volume buttons remain without function after being pressed twice, no matter for how long, until I remove the in-ears and plug them into the jack socket of my iPod again (that even though I’ve got a genuine pair of RE400i without any defects), and on my Apple USB-C to Headphone Jack Adapter, a short press of the volume up button results in an irreversible maxing out of the volume.

Shells made of metal. Look very nice. Their build quality is good.

One dynamic driver per side.




Sound:

Largest included black dual-flange silicone ear tips.

Tonality:

Fairly neutral leaning somewhat towards the warmer side.
Actually quite comparable to my InEar StageDiver SD-2 but with a brighter/less dark upper treble response.

Mild to moderate warmth in the root with the bass’ maximum quantity reaching around 5 dB in quantity above flat neutral at ca. 100 Hz in the upper bass. Flat extension into the sub-bass.

Ultimately a bit of warmth in the lower mids but not as much as my SD-2.
Flat central midrange with slightly reduced presence range but in the end still correct and neutral timbre.

Treble on the smooth and neutral/slightly darker side with a mild lift in the upper highs that ultimately leads to cymbals not always sounding sounding right but somewhat artificial/metallic. Never sharp or peaky.

Overall smooth, heading into a neutral direction and pleasant. Ultimately not as even as Etymotic’s in-ears but still some of the very best neutral-ish tuned dynamic driver in-ears regardless of price.

Perhaps the highs are brighter with shorter ear tips and/or a shallower insertion.

Frequency Response:


ER-4S-Compensation

To my ears, there is no such elevation in the highs but just a mild lift.


ProPhile 8-Compensation

Resolution:

Decent but nothing that’s outstanding or special.

Somewhat on the softer/slower side without really becoming muddy. Would still be appropriate for the ~100$ original price and is clearly nothing to worry about when purchased at around half of that or below; good value.

- - - - - - - - - - - -

Compared to the Etymotic ER2SE:

Apart from the bass and root, the two are tuned quite comparably neutral, with the ER2SE however still taking the lead in the end due to their higher treble linearity and evenness (my RE400i are a bit more forward in the lower upper and upper highs, with comparatively more metallic, less realistic sounding cymbals compared to the Etymotic).
In the bass and root, the HiFiMan have got an elevation that is stronger than the ER2SEs’ by around 4 dB, which makes them sound bassier and warmer (therefore their tuning would be more comparable to the ER4XRs’).

The HiFiMans’ bass texture is softer compared to the Etymotic, and the ER2SE sound somewhat tighter in the lows, too. The Etys’ bass control is superior.
In terms of resolution, I see the ER2SE one or two leagues above my RE400i – they just sound cleaner and their minute detail resolution is higher, just like their speech intelligibility and note separation in fast and busy parts of the music.

The ER2SEs’ soundstage appears larger than that of my HiFiMan in direct comparison, especially in terms of spatial depth and three-dimensionality, while the spatial width is more or less comparable.
The imaging (instrument placement and separation) and especially the portrayal of “emptiness” around and between instruments is more precise on the ER2SE.




Conclusion:

Smooth, neutral-ish sound that is heading somewhat into the warmer direction.
Rather “typical” dynamic driver technical performance but not muddy yet.
Cable could be better, just like the ear tip selection.


Photos:

FOREWORD

I got those IEMs for 35€ at my local store. I have no interest in making good advertising for the brand. I only share my opinion hoping some find it helpful. I also aim at supporting/disputing existing measurments and consensus with subjective impressions.

What I'm lookink for: I believe EQ is the cheapest, quickest and more accurate way of achieving excellent audio quality with IEMs. This is why the ideal IEM should have virtually perfect electro-acoustic properties before anything else.

What I listen to: Wide variety of music, but mainly jazz, guitare oriented genres and modern mainstream pop & hip hop. Few classical tracks that I know well for reference purpose only.
I also use IEMs as a chirurgical tool when recording/producing, Occasionnaly for field recording (Etymotics are best for that).

Sources: 192 kbs ogg/ 320 kbs mp3 made from CD quality flac files or CDs on Rockboxed FIIO M3K/ Thinkpad x230 under Debian using Pulseaudio Parametric Equalizer and MPV.

REVIEW

Build: It's surely not the most well built IEMs in it's pricrange. No flashy designe here... Just super discreet and simple. I like that. The lack of mmcx interface is a drawback though, and I don't really like the cable which lacks flexibility and sometimes gets on me nerves.

Tips: A lot of different types of silicon sleeves ar provided which is very nice. The small ones with waxguard gave me the best and most confortable fit. They allow deep insertion which is beneficial in this case. Sound isolistion was sufficient in most everydaylife cases, but pretty far from what an etymotic offers.

Sound: I see no drawbacks technically speeking. Well extended distortion free behavior is clearly shown. It feels almost unreal when turning the volume up. That is a sensation very specific to IEMs. The driver is extremely well damped, it feels precise and capable in very satisfiying way. Listening carefully really gives credit to innerfidelity and Rin Choi's Measurments. Just perfect.
Now tonally, it's quite off. The tuning makes it sound bloated, it severly lacks clarity. It's not unpleasant, but it cannot really be called neutral. It pretty much kills the chance to make it sound realistic and spacious. But you might like it, I have to admit I turn off EQ from time to time for a relaxing mellow ride.

When EQed: You'll have no trouble EQing to diffuse field or Harman target, or whatever sound profile you want. I personally use the Diffuse Field target a lot, it really manages to trick my brain, even slightly better than the Etymotic target (even if they are veeeeery close). These IEMs reacts per-fect-ly to whatever filter you apply to it: A perfect minimum phase system that can even handle pretty hardcore boost. Balanced armature based monitors or things like the Etymotic MK5 which uses an helmotz resonator as a tuning trick typically don't welcome EQ that warmly. In the end I found myself with something just as good as the ER2XR, even less distorted.

Conclusion: I just don't need any other IEM for my every day music enjoyment. If you're ready to experiment with EQ and elaborate a sound profile that matches your personal Head Related Transfere Fonction, it's just a perfect base to build upon. It's price point is very low now, and it can deliver pretty much everything the IEM world has to offer (perfect electro-acoustic behavior which translates into perfect "imaging" and cray amount of "details").

Bought them for $47 for my mobile believing the measurements used for full sized cans will have the same indication to real performance but found out the hard way the measurement don't apply the same way for IEM's - see this thread.

They aren't that much better than any Chinese $15 IEM. There are no free meals and to get quality looks like you'll have to be ready to part with $100 or more.

HIFIMAN RE400 WATERLINE REVIEW

INTRODUCTION

Hifiman is one those brands that you cannot forget when it comes to high quality audio, the product range is complete and unique, with premium and reference material, from the budget oriented to the super luxury.

The main reason i like their products is because of the outstanding build quality and reliability; premium products are really expensive, but at the end of the day you get what you pay for.

Disclamer:

My kind thanks to Hifiman for sending me the RE400 for testing purposes. My review is not biased in any way.


BUILD & DESIGN:

I really like the metal machinery there, precisely crafted, tiny and comfortable, during the first test i was really impressed how tiny and compact they are. The entire presentation of the earphones and accessories is nice and a really pleasing experience throughout: the casing, the foamy and velvety box inside, everything well presented and most importantly, well protected from the shipment; this is a really important feature because we have to imagine that the products travel all over the world before going into our hands. Design wise i would consider them minimalistic: the cable is not detachable, the first part of the cabling (the splitted part) is plastic only and the last part is covered with fabric, the two sections divided with the logo; L & R is printed behind the iem on the connection. On my version there is no mic nor input commands. I cannot stress enough how small they are, and in my opinion this is a good thing for a pair of all round easy fit and solid iem. I believe the connector has changed on a revision, as is now slightly different from previous model revisions, and probably more sturdy and ruggedized now. Everything comes within just 14 grams of weight, in line with other qualitatively equal models.


TECH SPECS & WHAT’S INSIDE THE PACKAGE

· Sensitivity 102 dB

· Driver size 8.5 mm

· Frequency 15 Hz - 22 kHz

· Impedance 32 Ohm

· Weight 14 gr

Re-400 has a neodynium magnet and a titanium 8.5 mm driver; the loudspeaker has been designed and produced directly by HiFiMan to guarantee maximum performance of the medium frequencies. The technical specifications are in line with the earphones of the same price range; the sensitivity is 102 dB, the impedance is 32 ohms and the maximum power reaches 30 mW.


Inside the package we can find:

· Hifiman Re400 In-Ear Monitor

· 7 pairs of Silicone Tips

· 1 carry pouch

· 10 Replacements for the nozzles filters

· 1 Clip


Two main things to consider that i really like: the pouch included is a plus, and for the tips there’s a pretty good selection of them, wether you fit bi flange, small or big tips. There are no foam tips included unfortunately, and i do not understand why the tips are presented in 2 different positions in the packaging, as if the bigger ones are a later addition to the overall packaging: some are on the front in the casing, some are inside the pouch. One thing to consider is that the 3.5mm cable is not balanced, and cannot be detached from the units, however, there’s a moderately long strain relief (compared to the tiny bodies). The included nozzles filters are a nice addition, in particluar for people with a lot of ear waxing; when they become impossibile to clean and/or ruined, you can simply change them withut worrying too much.


SOUND:

Overall the RE400 is a neutral sounding iem, the bass is a bit recessed and needs a some burn-in to shine in my opinion. I had to put the bigger tips to seal them better into my ear canals. The presentation is spacious and well-rounded. The soundstage is fairly large, and the earphones have a fairly open, airy, and uncongested sound.

Presentation:

The presentation of the RE400 is pleasant, wide and with a good overall sense of space and distance. There is less depth and height to the stage than with other multidriver iems, but the presentation is really good for this price point. Instrument separation is decent and overall very enjoyable. What i have found is a natural and pleasant presentation with great density that shines with an high level of clarity, especially with bright instruments and some particular tracks like the instruments found on the Chesky heaphone test disk.

Bass:

I have found the bass lackluster, even if i am not a basshead myself. With a bit of burn in it gets better, and i think that playing around with the correct tips helps a lot also. Definitely not a basshead iem, but i am able to live with it. The bass is there when you need it, but is definitely not so powerful. For a straight basshead i would consider something different, even if, to my taste, this can be enough and i was satisfied with the results after the burn-in process and the discover of the correct tip for my ear canals. Bass speed, on the other hand, is tight and precise, quick to play, and doesn’t linger too long; in my opinion this is really important. Definitely not a bass oriented iem, and again, if you are a basshead just choose something else.

Midrange:

Midrange is the best part of this iem in my opinion: it is very upfront and it blends very well with treble while retaining its space without going out of boundaries. The low-mids are well separated, and do not disturb some other frequencies; mids are really bright and some kind of vocals are better than the others: say for example forward female vocals are amazing: the overall result is a very open sound; obviously you miss some detail, some transparency, but at this price point, the midrange are really amazing, something that you are usually able to listen if you have an higher budget, on other brands.

Treble:

I like the treble because it’s sparkling and vivid, but not fatiguing. You lose a little bit of detail in the treble, but nothing to be worried too much. The extension is fair; overall to my ears the treble sounds good; it feels more natural and it has a good separation from the other frequencies, if you think that this is a single driver iem, the result is pretty good for the price range. I like the fact, again, that you can listen to them for hours without fatiguing your ears, i think that this has to do with the natural sounding, even if the treble are really sharp. In my opinion the treble is not affected too much from the break-in process, not quite as much as the bass to my ears; they are consistent out of the box and after 50h break-in period.


Overall sound impression:

Natural is the correct word for the RE400. The iem plays the music as it should be, without over emphasizing one thing or the other. The Midrange section is for sure the best one. Bass, on the other hand, is a bit lacking and you need some break-into get some and some good isolation, especially the sub-bass region, very recessed out of the box.


Final Impressions:

Well presented, natural and consistent: a nice tiny package that is good for the price and everyday listening without worrying too much about special sources. Buy them if you like vocals and midrange oriented tracks, do not buy them if you are a strong basshead and you want a lot of boom out of the box. Nothing special in the accessories, but the flange selection is nice, something they added later i guess, with the carrying pouch, that is a generic one and not personalized in any way with the name of the company or logos. I really like to listen to ambient tracks on those, especially filled with female vocals.


EQUIPMENT USED:

PC + Fiio E07K @ Foobar 2000 FLACs

Rockboxed Sandisk Sansa clip+

LG G7 thinq with quad dac

Hifiman RE400 Waterline Review

Liquid and Relaxing like Water


About Hifiman:

Hifiman was founded by Dr. Fang in New York - USA and is one of the most well-known personal audio companies in the audiophile word.

Hifiman has a wide variety of Hi-Fi, Reference and Premium class products like Portable Audio Players, Planar Magnetic Headphones, Desktop Amplifiers and Earphones/In-Ear Monitors like the Hifiman RE400, which I will now review for you.





Disclaimer:

I would like to thank Hifiman for providing me this sample for review purposes. I am not affiliated with Hifiman and/or any third person beyond this review and all these words reflect my true, unaltered opinions about the product.


Price:

The Hifiman RE400 is available for 49,00 USD.



Package and Accessories:

The Hifiman RE400 In-Ear Monitor comes in a small rectangular box, which has a semitransparent plastic housing.

The box includes the following contents;

• 1 pcs x Hifiman Re400 In-Ear Monitor
• 7 pairs x Silicone Tips
• 10 pcs x Nozzle Filters
• 1 pcs x Shirt Clip
• 1 pcs x Carry Pouch

The RE400 comes with a wide variety of silicone tips and some of them have a very unique shape like the bi-flange tips on the pictures bellow.



The carry pouch came separately, because the box is too small to carry all accessories. I think that Hifiman has added this carry pouch after some customer feedbacks.

The box includes also 10 pcs of Filters, which should help to protect the earphone’s inner components from dust and earwax.






Technical Specifications:

• Driver Type : Single Dynamic Driver
• Freq. range : 15 ~ 21000hz
• Sensitivity : 102db
• Impendence : 32ohm
• Cable length : 1.33m
• Plug : 3.5mm 3 Pole Unbalanced (TRS)

Design, Fit and Build Quality:

The Hifiman RE400 In-Ear Monitor has a pretty small and comfortable housing, which has a minimalistic design. The monitor housing is in silver color and is made of CNC machined metal that looks robust in my hands.



There is a small vent on the housing that is necessary to balance the pressure inside the housing.

On the front of the monitor is the sound nozzle that has a dust/earwax filter on the top, which can be replaced.



The cable of the RE400 is fixed to the monitor and is protected by relative long plastic strain reliefs where you can find also the left and right markings.



The cable of the RE400 is relative thin but and has a fabric coating which has pretty low microphonic effect. This fabric isolation goes up to the y splitter and the rest of the cable up to the strain relief is made of regular TPU material.



The cable has a plastic Y splitter, which sport the Hifiman branding and there is also a small metal chin slider in silver color same as the housing.



The Hifiman RE400 has a 3.5mm unbalanced 3 pole headphone jack with a 90 degree angled profile which is protected by a plastic housing.



The RE400 is very ergonomic due to the small and lightweight housing, which makes it ideal for long listening periods and to wear even while sleeping. The noise isolation is pretty good for an In-Ear Monitor with such a small design and has blocked much of the noise in relative noise environments like bus, train etc.






Equipment’s used for this review:

IEM’s : Hifiman RE400, Shozy Hibiky, Meze 12 Classics
DAP&DAC’s : Cayin N5II, Fiio M7, Chord Mojo, Xduoo XD10, Audirect Beam

Albums & tracks used for this review:

• First Aid Kit - My Silver Lining (Spotify)
• London Grammar – Interlud (Live) (Flac 24bit/44kHz)
• Laura Pergolizzi – Lost On You “Live at Harvard and Stone” (Tidal Hi-Fi)
• Minor Empire – BulbulumAltinKafeste (Spotify)
• Adam Taylor – Colour to the Moon (Flac 16bit/44kHz)
• Casey Abrams – Robot Lover (Tidal Hi-Fi)
• Vivaldi – Le QuarttroStagioni “The Four Season” (Tidal Hi-Fi)
• Steve Srauss – Mr. Bones (Flac 16bit/44kHz)
• Otto Liebert& Luna Negra – The River (DSF) – Binaural Recording
• Future Heroes – Another World (Tidal Hi-fi)
• Lorde – Team (Flac 24bit/48kHz)
• Tom Player – Resonace Theory “Album” (Tidal Hi-Fi)
• Liquid Tension Experiment 2 – Acid Rain (Spotify)
• Opeth – Damnation (Tidal Hi-Fi)
• Metallica – Sad but True (Flac 24bit/96kHz)

The Sound:

This review is written after a burn-in process of approx. 70 hours and I have used the stock bi-flange silicone ear tips.





Sound Signature:

The Hifiman RE400 is an In-Ear monitor with a relative balanced, slightly mid-centric sound signature. The overall tonality of this IEM is slightly on the warmer side of neutral and is ideal for long listening periods due the smooth and relaxing presentation.



Bass:

The bass of the Hifiman RE400 sounds pretty clean, controlled and very linear from the sub-bass up to the lower midrange and is nor bass-light neither bass-heavy in its presentation.

When it comes to the sub-bass region of the RE400, it shows moderate depth and rumble with average extension, which makes it not so suitable for genres like Trance and Edm music, but is good enough for jazz and acoustic music.

The midbass of the RE400 are tight, not very boomy and have the right quantity to add some warmness to the sound and to avoid a dull presentation. The bass speed is above average and has pretty good control for an IEM in this price category.


Midrange:

The midrange of the RE400 is where it really shines. It sounds smooth, forgiving and pretty detailed, especially at this price range. The positioning of the midrange is what it differs from other In-Ear Monitors in the same price class, because it sounds neither too forward nor recessed.

The overall presentation in the midrange is missing some transparency and is slightly veiled, which doesn’t sound unpleasant; on the contrary it gives the RE400 a special character. Both male and female vocals sounding quite emotional and pleasurable, especially female vocals have a more realistic presentation due to the brightness and sparkle, which comes from the upper midrange around 2-3 kHz. Male vocals are missing a slightly fullness and depth, due to the midbass / lower midrange tuning.

The upper midrange of the Hifiman RE400 sounds pretty controlled with a fairly acceptable level of sibilance and harshness. The song "My Silver Lining" of the group "First Aid Kid" is one of my new reference tracks to measure the stress in the upper middle range, which can be caused by female vocals, where the RE400 has done a great job.

The Hifiman RE400 sounds more realistic and successful with instruments such as guitars, drums and contrabass those have a relatively thicker tonality, than instruments like violins, flutes, etc. that are showing a thinner character.

Treble:

The treble range of the Hifiman RE400 is very linear and balanced like the rest of the spectrum. There is a slightly boost in the 6 kHz range that is adding some clarity and definition to the overall presentation and is avoiding hollowness.

Some instruments like Hi Hats are slightly recessed, which makes it a bit too difficult to hear, while crash cymbals have a moderate extension. The Hi Hat cymbals are quite clear to hear in genres like Jazz, but harder to define in faster tracks like metal music.

The overall detail level of the treble range is pretty good for this price tag and extension is on a moderate level which is acceptable for an entry level In-Ear Monitor. The treble tuning is very ideal for those who are looking for an IEM that is fatigue free and ideal for long listening periods.


Soundstage:

The soundstage of the Hifiman RE400 has moderate expansion, while the stage shows more wideness than depth. The stage has enough space to track the instruments in most types of music with low instrument quantities, but is not that suitable for songs with higher density, such as classical music.




Comparisons:


Hifiman RE400 vs Shozy Hibiki

The Shozy Hibiki has more bass quantity than those of the Hifiman RE400 that shows a more linear bass response. The RE400 has less sub-bass rumble and depth than Hibiki with faster decay and less extension, while the RE400 is slightly faster and has better control.

The midrange presentation of the Shozy Hibiki shows a more V shaped sound signature with a more recessed midrange. The midrange of the Hifiman RE400 is more forward and intimate than those of the Shozy Hibiki. The midrange of the Hibiki has also a brighter tonality with more presence that is adding additional sparkle to the timber of the Hibiki. This relative high peak around the 3-4 kHz makes the Shozy IEM prone to sibilance and can cause to ear fatigue. This was very noticeable in the song "My Silver Lining" of the group "First Aid Kid" where the Hifiman RE400 sounded much smoother and controlled than the Hibiki.

The treble range of the Shozy Hibiki is brighter and more pronounced in the 8 kHz region which is increasing airiness and sparkle, while the Re400 has a more natural and linear treble presentation, which makes it to the more ideal IEM who prefer less brightness and more relaxing presentation.

When it comes to the soundstage performance, the Hibiki shows more depth, while the difference for wideness is less noticeable, maybe slightly better with the Hibiki.

Hifiman RE400 vs Meze Classics 12:

The Meze Classics 12 has a more V shaped sound signature than those of the Hifiman RE400 with emphasizes to the lower and upper frequency regions. The sub-bass quantity and depth of this two IEM’s is nearly identical, while the RE400 has slightly better extension.

The bass and midbass region of the Meze 12 Classics sounds fuller and has more impact than those of the RE400 with pretty equal speed and control.

The midrange of the Meze 12 classics sounds more recessed than those of the RE400, which has a more intimate and emotional presentation for vocals. The boost in the upper midrange region around 2-3 kHz makes the RE400 more successful with female vocals and is adding slightly more detail without to be sibilant ant harsh.

The treble range of the Meze 12 Classics has a noticeable boost around 4-6kHz with a peak at 5 kHz that is adding more brightness, air and crispiness compared to the RE400, which has a more linear tuning. The Meze 12 Classics has treble extensions, while the Hifiman RE400 has better control and offers a more fatigue free listening.

The soundstage performance of those two IEM’s shows not a night and day difference. The Hifiman RE400 and Meze 12 Classics are performing head to head in terms of soundstage wideness, while the Meze 12 Classics has better depth performance.







Conclusion:

The Hifiman RE400 is very lightweight and comfortable to wear In-Ear Monitor with a smooth and relaxing presentation. The great vocal performance makes the RE400 to a real joy, especially with acoustic songs, while listeners who prefer more bass in their tracks will be less satisfied.


Pros and Cons:

• + Intimate and Emotional Vocal Presentation
• + Balanced Sound Signature
• + Fatigue Free Presentation
• + Very Lightweight and Comfortable
• + Lots of Ear Tips

• - Sparkle
• - Treble Extension
• - Maybe too Neutral for Some

VIDEO REVIEW



ALL REVIEW ARE DONE @ SOULSIKREVIEWS.COM and more insightful review can be found on our site.

INTRODUCTION

If you are on a budget then you are in for some good luck because Hifiman re400 might be just for you. Hifiman claims this IEM to be the “waterline” IEM, which means, not only them but the industry should be doing THIS with 99 dollars. Bit of a big claim? But I must say, they deserve the big talk. The re400 is not only small and compact but brings you quality that you would see in much higher end IEMs.

DISCLAIMER

The Hifiman re400 was sent me for a review by audioexcellence, a audiophile store in Canada. As usual, my reviews are not bias in any way.

ABOUT Hifiman

HiFiMAN Electronics is a designer and manufacturer of audio products including headphones, amplifiers, and portable audio players. Hifiman is known for its high-end audio products made under the brand Mee Audio. Its most popular products include the HE-400 which are full sized open back headphones and the RE-400 which is an IEM (In Ear Monitor). Both products are supposedly critically acclaimed for their sound quality

SPECS

Divers: Titanium coated 8.5mm dynamic drivers

Frequency: 15 – 22 Khz

Sensitivity: 102 dB

Impedance: 32 Ohms

Cable length: 1.33m

Plug: 3.5mm

 

WHERE DO I BUY IT?

If you are in Canada, https://www.audioexcellence.ca/ is the place to go, not only for this product but for any hifi products, their price is competitive and ensures quality service. Their store is well worth a visit if you are located within the GTA.

Internationally, amazon is your best bet far as I know.

 

BUILD QUALITY

HOUSING: the housing is made of aluminum and is very small and compact.

 

Cable: the cable is fabricated cable up to point of the splitter and then it is

rubber/plastic material from then on. The slider is metal, which is very nice touch. It terminates in a 3.5mm gold plated right angled jack.

 

Accessories: A lot of tips for any fit, however I found the comply foams to be the best. A very nice hard carrying case that is practical in size and portability is included. There are also extra filters in case you damage the filters with earwax, which is a nice touch and shows that HIFIMAN wants you to keep the IEM for a longer time.

 

Overall, the build quality is exceptional for 99 dollars. From drivers to the accessories, it screams quality. Also, the isolation and fit was perfect for me. There is 2 ways to wear it. Straight in or over the ear (found the 2^nd fit to eliminate any microphonic)

 
PRACTIALLY

This IEM would be something I would recommend my university friends that are not audiophiles because of its cheap price point and what you get for it. With the comply foams, there was much more isolation, however even with the normal tips included with the re400s, the sound isolation was enough to be used in quiet places like the library and loud places like the gym.

SOUND QUALITY

GENERAL: These are neutral sounding IEMs. The bass is not as extended as modern bass heads might like it, and this might be a turn off for some people. However, the fact that you can hear the music you love, the way it was recorded, the way it was supposed to be heard for 99 dollars, is something to appreciate. If you are like me and listens to almost anything, these are perfect. You can hear these for hours and hours without any problem because there are no sibilant highs or no booming bass that might bother you in long listening sessions. Everything is clear and represented “the way they are supposed to be”

Sound Stage: the sound stage is very intimate, which may be a good thing for some and a turn off for others. Again, priced at 99 dollars, these are exceptional in sound stage and imaging.

Final Thoughts

Hifiman re400 really did amaze me with its price to performance ratio. I wish to see more budget iems like these in the future. I truly believe they deserve the title of “waterline.” 

I am only listening to acoustic music, So I had no issue with the amount of bass (only plugged to my FIIO X5II, Flac, APE, Highres and DSD files). Even though they are not as tight as on my Shure's Se425 they are well balanced with the rest of the spectrum.
Slightly on the warm side but perfectly balanced, not in the face , musical, smooth apart from a little peak on the high mids, they have an amazing respect for the timbres, which is for me the main point.
The relative lack of definition participate to how "liquid" the music is just like in concert. Everything is integrated in a delightfull way, not much sticks out.
On some tracks I was expecting a little bit more dynamics but I have never heard a pair of IEM's that accomodate so many different style of recordings. 
Bought second hand (perfect condition) for 40€, it's the bargain of the century.
Higly recommended for classical music lovers.

Where do I start? These honestly sound like the HD600/650 in IEM form. My previous go to IEM was the Klipsch X10 ($100), followed by the Klipsch X20i ($539). What is amazing, is that the RE-400 sound smoother, are more realistic, have better treble extension, AND have better soundstage than the X20i. And these cost just $79! I am continually impressed by these the more I listen to them. They seem to work with every genre too. For classical, they bring out every instrument texture to make them sound realistic. For pop and EDM, they have decent impact and sub bass extension, but are not for bassheads. I would describe them as neutral, and very slightly warm. Some may say they don't have good sub bass, but I disagree. If you are used to Hifiman's planars like the HE-400i and HE-560, you will notice these have extremely similar bass presentation. Mids are fantastic, very realistic and right where they sound be. Maybe slightly elevated compared to most IEMs, but only very slightly. Treble is so smooth, no peaks at all. I must say, the tonal balance is smoother and more realistic than many over ear headphones such as the Beyer DT800 and T1, Hifiman HE-400i, and Shure SRH-940, and sound very similar to the Sennheiser HD600/650 in the mid and treble regions.
The only con I can think of is the supplied ear tips may not fit people with smaller ear canals like me. The smallest size is ok for me, but doesn't seal as well as foam tips, and the next size up is too big. So I ordered Comply foam tips (the TS-400 size) and hopefully those will get a better seal. However, even without the best seal, it doesn't seem to affect the sound that much, because they already sound fantastic. 
Considering these sound significantly more balanced and natural than what the Klipsch IEMs have to offer, at under the $100 price point, is a huge accomplishment in my book. You probably wont find a better sounding audiophile IEM under $100, or maybe even up to $300. I wouldn't be surprised if these match the performance of the king of dynamic IEMs, the Sennheiser IE800. Hifiman sure knew what they were doing with these, and I can't recommend them highly enough!

Source: Macbook 12 with Audioquest DragonFly v1.2
 
Comfort and Construction:
 
Overall the comfort level was good to me for an in-ear monitor. The key is to correctly size the inserts. Cord length is good for this type of ear monitor. Ended into a 1/4” plug with a 45 degree angl. For use on an iPhone or iPod, this may be a slight distraction. The cord is sturdy. Seemed to have good thickness without being too thick. There are no controls on the cord. This could be a deal-breaker for some.
 
Sound:
 
Overall, the RE-400 has a good sound. The highs are crisp and detailed. The mids are solid. It does lack base, but most in-ear monitors will be the same. Isolation is good for an in-ear monitor. No active noise cancellation, but with a good fit using the correct inserts, the isolation is satisfactory. I was impressed with the clarity of these. Good sound separation.
 
Thoughts:
 
Easy to recommend if you are looking for a reasonably priced in-ear monitor. Good sound and comfort. Need to decide if the angled plug will detract or lack of in-line control forces another choice.

A bit of background:
 
Now to my review:
I think my demo of the HifiMan RE-400 was one of the fastest purchasing decisions I have made.  Compared to the other in ears I was testing, they just sounded so "right" with a flat midrange and such natural timbres!  I have had other similarly quick demos but those mostly involve me ripping headphones off my head because of how badly coloured they are, but that is another story.  RE-400's were clearly the most faithful earphones I had heard that day regardless of price (I had listened some earphones costing 20x the price of RE-400!)
 
Anyway I think it is customary to break reviews down into sections, maybe BASS, MIDS, TREBLE etc. so I might do the same:
 
BASS:  Flat.  Not elevated or rolled.  Just flat down to 20 Hz like a planar.  Tight.  Not boomy.  Detailed.  Acoustic.  Fast.  A little shy when not driven with enough power.  Excellent.
 
MIDS:  No peaks or dips.  Clear.  Perfect timbre.  Fast and clean.  Resolving - this is not the same kind of (overly) airy sense of resolution you get with BA earphones, and subjectively there is not as much finer microdetail as some of the multi BA solutions, but the overall faithfulness of timbre is higher and resolution is hardly lacking*.  *Actually I think part of the subjective impression of resolution might be down to the frequency balance which I will discuss that later.
 
TREBLE:  Good timbre, moderately good extension.  I can still make out all the cymbals and acoustic instruments all sound remarkably lifelike.  There is some lack of air due to rolloff in the high treble.  Mid treble also needs some boosting with EQ.  I added +6dB centered at 6kHz and +10dB centered at 16kHz, however you may find different adjustments more to your taste.
 
I use these earphones with my Sony ZX2 DAP, which from experience may be slightly lacking the power to make the bass wake up but, interestingly the RE-400 are not holding back this high end DAP. The RE-400 will improve with better gear such as Chord's Mojo, or even some other higher powered DAPs.  The RE-400s are incredibly transparent and revealing.  Colourations in source components or amplifiers are laid bare.  They are not harsh (though there is some very slight sibilance splash).  Yes it makes sense to use this (USD) $100 earphone with high end portable gear like Chord Mojo, Sony ZX2, Astell & Kern AK240 etc.
 
I mostly listen to classical and jazz, however I still listen to some heavy metal.  With classical and jazz the technical prowess of these earphones is hard to beat at any price.  For heavy metal, the technical ability and truthfulness is usually also good, however poorly recorded material will sound however it sounds.  I can just back off the treble EQ to compensate if the recording is too harsh for high volume listening.  When playing acoustic music you want to be able to appreciate the full performance in all it's nuance and dynamics.  Timbres are very convincing.
 
Anyway I could continue to waffle about the technical ability of this earphone, however at the end of the day it will be up to the listener and his gear, music and tastes to determine if they like this earphone or not.  I almost overlooked these earphones, firstly because of the price (I think many others do as well), but secondly because I was not aware of just how good they are regardless of lack of hype.  I am sure that the few listeners with good ears who have discovered these gems are happy that their performance is not widely hyped.  It's a small miracle that this level of sound quality can be found for so little money, especially considering the general trend in the market towards more costly designs.  I recommend for everyone to try these earphones, especially audiophiles who value neutral, transparent, and low distortion sound.  Do NOT make the mistake to overlook these earphones because of the low price.

Unfortunately, I find these to be the most overrated iems going on the market at present. Anybody who claims that these have sufficient bass response are just deluding themselves, or others. They are extremely bass shy, to the point where it just ruins the music. I also own the Trinity Deltas, Vsonics vsd3s, and senns cx-300ii; and the Hd-600s and Fidelio x1 for full sized cans. Even next to the hd-600 which is hardly 'bassy' is not lacking in this department, while the re-400s are just deflated there. Such a shame.

The midrange is lush and smooth, and the treble is just right. The soundstage is very narrow, however, and the presentation lacks clarity and transparency. Also, the build quality is truly terrible: the wire  from the Y split to the driver casing is very thin and the actual connection to the case is weak (it separated barely 6 months into usage). The tip assortment is fine, with the Comply Foam tips giving it a bit of extra bass hump it sorely needs. However, they make the presentation even narrower and more congested than it already is. Sillicon tips uniformly give the same bassless response.

These are horrendously overrated.

***This is a tl;dr: review. please refer to other reviews for a more in-depth analysis on their amazing sound.***

For $100, you simply won't be getting anything better sound-wise than these cans, and a lot of happy owners will back me on this one. The mids are heavenly, the treble is smooth yet detailed, and the bass is tight and accurate. However, don't buy them just yet. The build quality is not up to scratch. In fact, when I asked the saleslady for these cans, she immediately suggested that I get it recabled from the get go. How I wish I took her advice. Barely 48 hours in and the cable on the right earpiece is fraying, just below the strain relief. The copper has gotten exposed, and while photos might not do them justice, and while $100 is relatively cheap in audiophilia, it is ridiculous that they are showing signs of tear 2 days in.Absolute let-down. Granted, YMMV, and I might have gotten a faulty unit because some owners have owned them for years and theirs are still apparently alive; however, if you plan to use them on the go or while exercising, look somewhere else, or get them recabled.

I will update this review if my unit breaks. It's a shame really, I dig the sound so much. If they do break, I'll definitely be getting them recabled at cost. I dig the sound that much. Photo of the fraying cable below.

I bought these in early May based on nearly unanimous recommendation from people on a bunch of websites, and I must say they don't live up to their reputation. Some of the common things people pointed out were that they are excellent for the price, they have great mids, and they have bad build quality, the bass could be better, and that they are great for all genres. Most of these points definitely stand up, I don't think I have ever heard better mids in my life, they are fairly cheap, but to me they have nothing else going for them. The bass isn't just leaving more to desired, it is so bad it makes some genres hard to listen to, it is almost comically weak, more like a tickle than a punch. They aren't especially neutral, they are just very mid heavy. I guess it sounds neutral at first glance, but the lows are extremely recessed, and the highs aren't very sparkly, they also have bad sibilance in a lot of cases. It is basically the opposite of the classic "V-shaped" sound signature, whereas normally mids are recessed and there is too much emphasis on lows and high, these have way too much emphasis on mids and bad lows and highs. They also definitely don't work for all genres. When listening to classical instrument seperation suffers, soundstage seriously suffers, bass suffers, highs suffer, and volume suffer. For metal the vocals are amazing but a lot of the rythm is lost in the weak bass, funk is amazingly smooth and probably the best genre for these, for techno in general they are terrible due to the bass problems, although as usual vocals stand out and are excellent. 
 
In terms of physical qualities they aren't great either. They look quite cheap, which is the downside of their otherwise nice minimalistic style, the 3.5mm jack is very obviously low quality, as someone who fixes headphones on a regular basis that stand out like a sore thumb, the cord definitely also feels a bit flimsy and I don't expect it to last long. If you don't wrap your earphones around the back of your ear these suffer from constant annoying microphonics leaving you with no obvious choice except to wrap the, but they also have a tendency for the wire to constantly fall off my ears, which can get very frustrating at times. The sound isolation is mediocre, nothing really to complain about but also not worthy of praise, I often have to bring the volume up a lot compared to where I normally do with IEMs. The choice of included tips is strange to me, there is a bunch of flanged ones that scratch and irritate the inside of my ears, there is ones that are way too small, ones that are way too large, and only one set that is similar to what is normally included with all IEMs which is medium sized rubber tips, but it's still not exactly the same it's like a half flange, the tip is two different sizes but it isn't separated, 
 
In conclusion, I definitely do not recommend these earphones. I have had 40 dollar Sony earphones perform twice as well as these for less than half the price, and they lasted me almost 2 years, where these apparently have a tendency to fail after only a few months. These are an exceptionally mediocre pair of earphones with a huge list of major downsides that are only redeemed at all by the excellent mid range performance.

The neutral, balanced sound of these earphones made me realize what good audio could sound like. They reveal and retrieve so much detail, which at first can come across as only thin and lifeless, but if you're like me, that's because you are used to hearing bloated, bassy equipment that is made to appeal to the masses.

The metal housings are nice, but that's about the only good thing about how they physically feel. Their build quality and durability are poor, the cable is lackluster, and the eartips feel cheap.

I believe I paid close to $100 for these back in 2014/2015. They're currently on sale for $20 through Amazon and Hifiman. At $20, they're a no-brainer for sound, even in 2021, imo. But the fact that they will eventually break much sooner than earphones of this caliber should, gives me hesitation. I would gladly pay $100-$150 for a MMCX/2-pin version from the factory.

Build / Fit
They are much smaller than I expected. The aluminum casing is nothing too special, it looks very clean, and simple. The wires above the split are very thin with a feel like they could break easily if you use then regularly on the go. But, below the split is a very nice cloth cable that leads into a 45 degree plug. The fit seemed very loose, even with the comply tips.
 
Sound
Neutral with a very slight rise in a bass. For the price, even for the $99 MSRP, they are incredible. The detail and sound stage are as good or better than some full sized headphones I've listen to. IMO the bass could use just a bit more impact?, not too much though. The Highs were just great, non-fatiguing, but still held the detail very well. The mids are neutral, nothing sounded too out of place. Again, for the price you can not get better than this. There is a reason why HiFiMan calls them the waterline.
 
Packaging
I guess this is something take into consideration? I thought is was very simple, clean, like the headphones that lay inside. There is a thick plastic sleeve that I thought was neat.
 
Overall
They are fantastic pair of IEMs to keep in your collection, I will be using them when I am too lazy to put on my SE-215s or is a rush. BTW, Microphonics are a thing. I love the RE-400s, but they feel like something was holding them back from being spectacular.