Review: Head-Direct RE0

[antonyfirst]

This is a review of the Head-Direct RE0. I got them as a review sample a week ago, I have fully burned them in (50-60 hours), and listened to them for many hours a day. I have tried the provided tips, as well as other tips I have at home, and I am finally ready to write what I think of the earphone.
Before starting the review, I want to point out that the fact I got a review sample doesn't prevent me from writing exactly what I think, being it bad or good for the earphone. I don't like when people feel obliged to write a "good" or "enthusiastic" review because they get a review sample. I think, actually, that the time and effort spent evaluating a review sample in order to honestly capture its character more than pays the benefit of owning it.
So, after this premise, I'll be pleased if you want to read my thoughts.

Head-Direct RE0

The RE0 are offered as the top of the Head-Direct IEM line. I haven't asked Fang what price they are offered for, but a few days ago I went to their Website and found them for 200$.
The RE0 have a different look than the RE1. The outer casing has a "milled ring", which makes them look less cheap and sturdier than the lower model. The RE0 looks remind me of the OVC T25 IEM I tried a couple of years ago, which is also the same look the V-Moda Vibes (old fotm) had. As it has been pointed elsewhere, this design is pretty standard for earphones in China. The RE0 look very low profile in the ear, just like a Sennheiser CX300.
They have two small holes on the external side of the earpiece. They aren't the most isolating canalphones, but hold their own even on train, especially with the right choice of tips.

Going from memory, the cable is more flexible than what was used with the RE1, so it's less annoying to use while walking. The cable is still microphonic, and requires a clip to hold it to one's clothes.

Being the RE0 dynamic driver, they benefit from burn in. I found the major changes to be in the first hours of use. I decided to leave them burning in for about 15-20 hours before starting to listen to them extensively.

Tips

I remember having liked the big, clear and soft biflanges Head-Direct provided with the RE1 early this year. Anyway, after getting used to foam tips with other IEMs, I found it hard to return to silicon tips. More precisely, these biflanges don't seal well for me, and often they make me feel like having my ears stuffed with cotton, or like when my ears are closed on an airplane.
After a few days of fight against these biflanges, I decided to drop them in favor of Ultimate Ears foam tips, which I have at home. For me, they make a big difference comfort-wise, they give me a lasting seal, and also improve isolation. The sound isn't changed. In the past, I found Shure black foamies to make the treble softer. These UE foamies, to me, don't soften the RE0 sound signature.
The nozzle is the same width as Ultimate Ears, Sony and Sennheiser IEMs.

Sound

My main concern with the old RE1, about which I wrote when I reviewed them, was the lack of treble, which often made me turn up the volume in order to hear the right high frequency energy. Vocals were very meaty and full sounding, cymbals, didn't hit hard and didn't convey any strength. The positive side was the total lack of sibilance, given by the strong lower treble recession.

The RE0 are a different animal.

Bass

The bass of the RE0 is pretty linear, not bloated, not weak. Very quick. It does a good job in providing the right volume and decay to bass notes. Its "tactile feeling" is improved when I switch from unamped to amped. The two amps I used were AMB Mini^3 and iBasso T4. The Mini^3 is more transparent, so the bass gains authority, but is never intrusive. The iBasso T4 bloats the midbass a bit, adding an unnecessary fullness to that frequency range.
Deep bass is not represented. The bass quality of the RE0 is on par with most good quality IEMs (like the Triple.fi). It's truthful to the recording, but lacks two things to give the ultimate pleasure: real depth, and the wonderful definition that makes the Apuresound ER4P bass sound like "carved in stone".

Midrange

The midrange is pretty flat to my ears, or a bit recessed. Vocals are not as exciting as with Apuresound Etymotic ER4P. The Etys have in your face mids, that I wouldn't consider neutral, but there's something to their aggressiveness and rage that make me love them. The RE0 behave differently, and vocals sound more laid back. This is not soundstage-related, but rather a matter of involvement and emotion that should be conveyed by vocals. The fact that vocals don't sound as "in your face" as with the Apuresound Etys doesn't make them automatically recessed, but I think that a slightly more forward midrange would make the overall sound more exciting.
Electric guitars don't snarl. They are on the same level than other instrument. You hear them clearly, they are part of the system, but you don't feel them.
The overall midrange, anyway, is clear and doesn't give enhanced fullness to vocals like the RE1 do. The strong "chesty" character that the RE1 provided to vocals was the result of a strong recession in the highest part of the upper midrange and part of the lower treble (which means 6-8kHz). The RE0 don't suffer from this at all.

Treble

All this brings us to treble. Treble is what I like most of the RE0. It's flat. Totally neutral, flat, extended to 16kHz. It won't amaze you, just because it's not enhanced, nor lacking anything. It's detailed, clean, exciting. The lower treble finds a good balance between smoothness and crispness. It's never sibilant, yet cymbals crash nicely and are involving. In the past, I learned to hate sibilance, the result of a peak in lower treble, but I ended up hating strong smoothness (Stax SR-001, Head-Direct RE1), which isn't realistic either, if resulting from missing frequencies. The RE0 have the most honest and flattest treble I have found in a portable headphone.
Lower treble doesn't give the "amazing" feel you can find with the Triple.fi 10 Pro or Etys, but it's more accurate than both and doesn't have the shortcomings the other two have (both the Triple.fi and stock Etys are sibilant to my ears).

Soundstage and Amplification
Soundstage is normal for a IEM. I think it improves with amplification. Both the Mini^3 and the iBasso T4 give a sense of tridimensionality to the sound. The Mini^3 does this better than the iBasso T4, and the overall sound of the Mini^3 is more gentle and refined.

Speed
The time resolution that the RE0 have is on par with that of the ER4. The RE0 have more natural decay, though, while the ER4 show shortened transients.
My understanding is that dynamic driver IEMs aren't less detailed than armature IEMs by default, and probably this idea was something brought into common thinking because dynamic driver IEMs are a younger technology.
I understand it has been in part the issue of size: only lately, manufacturing technology reached the level where can make a dynamic driver small enough to shove in someone's ear. The demand for IEMs went up sufficiently for manufacturers to invest in that. There is a late trend where many manufacturers are preferring dynamic drivers over armatures: some examples are Atrio M5, Sony EX700, Sennheiser IE8, and the Head-Direct series.

Conclusions

While not being the most exciting IEMs in existence, as they don't add anything to the sound, the RE0, are probably the most balanced IEMs I have owned. There are no obvious peaks and valleys in their frequency response, which in my book is something to look for. Instead, most universal IEMs (almost all IEMs I have reviewed and are in my signature) soffer badly from this. I'll be looking to receive the Klipsch Image X10 to see how they behave in this regard, as they are well appreciated to have a great timbre.
There is something that could be done to improve the sound of the RE0: tighter bass, better bass extention (depth) and more forward midrange would have left me with nothing more to desire.
As they stand, the RE0 are a lot better purchase than the RE1, especially considering that the price difference between them is very small (30$-40$). I consider them also better value than the Yuin OK1.
While the Apuresound ER4P keep being the best IEM I have heard (since even if it's very coloured, I can't help but love the way bass is represented and the total emotion they convey), I think the RE0 are very nice for the price they are being offered. It's up to you to decide if their sound character, strong points and shortcomings will fit your needs, taste and music.
Comfort issues I had with the provided silicon tips can be easily overcome with foamies. I haven't had a chance to try Comply tips, but that's surely a route that should be followed.

Tony

[_Toki_]

Thanks for the review. How would you compare their midrange to that of q-jays (which is thought to be distant and recessed too)?

[antonyfirst]

That was one of the few IEMs I never had a chance to try. I recall people forgetting them soon after the fotm ended. Sorry.

[Audio-Omega]

What about its build quality ?

[antonyfirst]

Originally Posted by Audio-Omega

What about its build quality ?

What would you like to know exactly? I have already talked about the cable and looks. The RE0 look cheaply made, but also sturdy.

[jant71]

Thanks, Tony. Kinda disappointing. The tight well defined bass and slightly forward mids with great texture and emotion is what I get and love with my modded SF 5. They just made the UM2 mids sound thin and boring and beat the UM2 bass even worse. I had hoped the RE0 had a bit of the new Sennheiser in them and be a better value. I guess not. Not to mention your report of a normal size soundstage which would again be punished by the SF 5 if that is the case. Sounds like they fall short in just the perfectly absolute wrong areas for me.

I had hoped that 15Hz low freq spec(vs. RE1 20Hz) would mean some good low end extension. Maybe not.

Tony, are they fairly quick or sluggish vs. the ER4? Maybe they need even more burn-in and will open up. Still interested to hear what ClieOS and Frederik have to say before I dismiss them but they are not off to a good start in my book.

[ZoNtO]

I have a feeling I'm not going to be buying these like I anticipated... Too many other good phones right now at good prices. They just don't seem to be worth 200 bones.

[antonyfirst]

Originally Posted by jant71

Thanks, Tony. Kinda disappointing. The the tight well defined bass and slightly forward mids with great texture and emotion is what I get and love with my modded SF 5. They just made the UM2 mids sound thin and boring and beat the UM2 bass even worse. I had hoped the RE0 had a bit of the new Sennheiser in them and be a better value. I guess not. Not to mention your report of a normal size soundstage which would again be punished by the SF 5 if that is the case. Sounds like they fall short in just the perfectly absolute wrong areas for me.

I had hoped that 15Hz low freq spec(vs. RE1 20Hz) would mean some good low end extension. Maybe not.

Tony, are they fairly quick or sluggish vs. the ER4? Maybe they need even more burn-in and will open up. Still interested to hear what ClieOS and Frederick have to say before I dismiss them but they are not off to a good start in my book.

Hey Jant, how did you mod the SPF 5 Pro? I had a really big problem with their treble spike. It was horrible with the stock cable, and still noticeable when I made all those mods 8 months ago. I had the same problem also with the Triple.fi, even if at a lesser extent.
I think the RE0 are similar in bass to my old modded SPF 5 Pro and beat them at treble, but the Supes had better soundstage depth.
I think you should listen to well burned in Apuresound ER4P to understand what I mean by defined bass. It's not something that I could apply to either the Super.fi 5 Pro or the Triple.fi.

Regarding speed, the RE0 hold their own with the ER4. I find them very nicely nuanced, with very good time resolution.

[jant71]

Not the 5 Pro tony, the new one. It has a bigger soundstage and better mids than the older ones. It needs better tips( mainly medium Shure clear flex) and improves nicely with the 75 ohm S-adapter. I like it better than anything except the SF 3 with cable upgrade and S-adapter which still has better bass, speed, and soundstage/separation. But the SF 5 has slightly better mids and treble extension and is much more comfy(elastomer cable with no memory wire) and looks nicer/is much smaller.

To be fair I never went back to the Triples to try any mods as the price and huge size/memory always kept me away as well as favoring the SF 3's separation and forward mids as a better base to build upon.

Interesting about the speed. I was thinking maybe they need mucho hours of burn-in and the driver would loosen up and speed up giving tighter, more well separated bass which would add to the perceived extension and definition.

I know what your talking about with the bass. I first heard this with Stock ER4S Vs. modded SF3. The modded 3 was so much tighter and easily kept up with the fastest most complex things I could through at it. I could turn up the bass EQ twice as high as the ETY and compare how the ETY would start to break up and bloat while the UE kept it together. Not that I need a lot of bass, I was just testing them at 50 Hz to get an idea of how much tighter/more composed the bass was.

[lelek45]

Originally Posted by antonyfirst

I consider them also better value than the Yuin OK1.

Thanks a lot for the review!! These IEMs look very interesting to me, could you please elaborate more on why you consider them to be better then OK1? I found OK1 to have almost perfect sound for me, closest to my K701 (in earbud mode), unfortunately they are not IEM, so I'm still looking...

I especially appreciate YUINs soundstage, and most natural tone I heard from portable headphone (on pair with k701). Also, treble extension and speed are amazing. How RE0 in these departments? According to you, they are quite similar overall, except of very forward midrange of YUINs (it actually not a small difference...)

[antonyfirst]

Hey Lelek.

The OK1 have much better soundstage width than the RE0, and more precise instrument separation. Though, the OK1 fall short in the bass department, rolling off pretty soon and being a bit on the lean side, and I also feel them less neutral overall. The OK1 have a certain boost in the lower treble (about 3-6dB if I remember correctly), which makes them sibilant sometimes. The problem is not nearly as annoying as with Etys (or even Triple.fi), and anyway makes the OK1 very detailed, and the treble etched. The RE0 have a lot more balanced treble, being it flat, very extended, which I prefer over OK1's treble, even if the former calls less for your attention. I like the bass of the RE0 more than that of the OK1. The bass is present, quick, clean, very well balanced and doesn't give the impression of weakness, nor the idea of being bloated, on the opposite side. If it went as deep as an Etymotic, it would be perfect.
For sure, you won't find the RE0 dark like your Sennheiser IE8, which, after your description, I don't think I would like either.

[lelek45]

Thanks Tony! Such a detailed answer, as usual. These seem to be my phones. I will give them a try.

Originally Posted by antonyfirst

The OK1 have much better soundstage width than the RE0, and more precise instrument separation.

I guess YUINs are unbeatable here...

Though, the OK1 fall short in the bass department, rolling off pretty soon and being a bit on the lean side, and I also feel them less neutral overall.

Absolutely agree. Minor issue, considering all good things, if RE0 perform better, I don't mind.

The OK1 have a certain boost in the lower treble (about 3-6dB if I remember correctly), which makes them sibilant sometimes.

Agree again. Can live with it. You are always such precise with descriptions.

For sure, you won't find the RE0 dark like your Sennheiser IE8, which, after your description, I don't think I would like either.

That's good thing. I hate dark, cloudy sound. Yeah, IE8 was quite disappointment... not recommended. It seems that Sennheiser wanted to win the price for biggest bass, I'm sure they won.

[silver__wombat]

Hi i was wondering if you could tell me how long the cable is? Do they come with an extension like the RE1 and RE2?

[antonyfirst]

The cable is longer than that of the RE1 and doesn't need an extention to be used comfortably. The length is just "right". I don't know if the commercial product has also an extention cable.

[silver__wombat]

Thank You. I think I just found my next iem's.