HiFiMan RE-ZERO Review


First and foremost, a big thank you goes out to Fang at Head-Direct for sending me a sample of the RE-ZERO IEMs for review.

If you’ve been keeping up with Musical Musings, you’re probably well aware of my current love affair with the HiFiMan RE0 IEMs. They are the current crown jewel in my IEM/headphone collection and hardly a day goes by in which I don’t pop them into my ears for a listen.  With that in mind, when the HiFiMan RE-ZERO (yes, that is their name) IEMs were announced this year prior to the 2010 CanJam Head-Fi event that was held in early June in Chicago, I was understandably excited about them. Envisioned as a 1000-unit limited edition to commemorate the three year anniversary of the RE line of IEMs, the RE-ZEROs immediately piqued my interest. Featuring a much lower 16 Ohm impedance, and a silver coil for “more real bass”, these were intended to be used portably, straight out of a DAP or other source without the need for an amp.

Over the past week or so, I’ve been listening to the RE-ZEROs almost exclusively and for a great deal of time in each session. I say “almost exclusively” because I’ve also been comparing them to the RE0s, HiFiMan’s other inexpensive heavyweight. So, do the HiFiMan RE-ZERO IEMs offer Hi-Fi sound quality at Mid-Fi prices like the RE0s and are they worth the $20 price increase over their predecessors? Read on to find out.

Technical Specifications

Driver: 9mm Dynamic
Frequency Response: 15Hz – 22KHz
Impedance: 16 Ohm
Sensitivity: 100db/1mw
Cable Length: 1.2m/4ft

Packaging and Accessories

The RE-ZERO IEMs arrived in a clamshell plastic case that is a mirror image of the packaging of the RE0s, aside from a few coloring differences. The accessory pack is also virtually the same, featuring six pairs of silicone single flange eartips in varying sizes, two sets of bi-flange eartips in small and large sizes, five pairs of replacement filters and a shirt clip. The only difference here is that the RE-ZEROs include two different adapters that allow you to plug the RE-ZEROs balanced plug (more on this later) into a standard 3.5mm jack.

Of the two adapters, one hard and one soft, I preferred the slightly bulkier hard adapter due to the fact that the soft adapter was prone to causing channel imbalances if the plug was positioned wrong and the static it occasionally introduces when it is jostled.

Design and Build Quality

At first glance, it can be pretty difficult to tell the RE-ZEROs and RE0s apart. First off, the housings are slightly smaller than those of the RE0s and feature a very classy matte gunmetal finish. The Y-splitter and chin slider are also clad in a similar gunmetal finish and the Y-splitter features painted on lettering spelling out HiFiMan and RE-ZERO.

Build quality is, as expected, very solid. The housings are made almost entirely from metal with plastic nozzles and felt/paper filters. Extending down from the housings are familiar black strain reliefs which lead into a black PPE cable that seems to be the same one used in the current hardware revision of the RE0s. The cable terminates into a 45 degree angle 4 pole 3.5mm plug. The inclusion of a balanced TRRS 3.5mm jack is one of the biggest changes to the RE0 design and one that leaves me a bit confused.

I’m going to go off on a bit of a tangent here and talk about the TRRS balanced plug HiFiMan has decided to go with instead of the traditional 3.5mm TRS connector that most consumer earphones utilize. I’m puzzled as to why HiFiMan would choose to fit the RE-ZEROs with a balanced plug versus a traditional mini jack because it presents a number of questions.

Balanced plugs only appeal to owners of balanced headphone amplifiers, an incredibly small subset of the audiophile market (likely less than a single percent), or people who own DAPs that accept balanced plugs, an even smaller (if not nonexistent) corner of the market. Because of the decision to use a balanced plug, the RE-ZEROs cannot be used properly with the vast majority of audio players, portable or otherwise, without an adapter. This is especially puzzling considering that the RE-ZEROs were designed with much lower impedance than the RE0s and are intended for portable use. Well, being forced to carry around and use an additional adapter, unless you’re one of the few who is in possession of a balanced portable amplifier inevitably adds more bulk to a portable setup and is one more thing to carry and keep track of. What happens if you misplace the adapter? What happens if you forget to bring it along with you? Well, you’re out of luck.

Not to mention, since the RE-ZEROs are low impedance IEMs, they theoretically shouldn’t need an additional amplifier to sound great in a portable setup to begin with. Because the RE-ZEROs are low impedance, I don’t feel the need to bring along an external amplifier when I go out and simply run them straight from my iPod Touch and they sound fantastic in that capacity. This makes me wonder, if these were designed with very low impedance ratings which is highly beneficial for portable usewhy use a balanced plug? Wouldn’t a standard mini jack make more sense in this application since it would offer inherent advantages to users who wish to use the RE-ZEROs without a portable amplifier?

The RE-ZEROs are a 1000 unit limited edition but these clearly possess a great deal of mainstream appeal. Given their relatively low price tag on a price-to-performance scale, similar to the RE0s, one has to wonder why the choice would be made to use a type of plug that appeals to such a niche market instead of the widely accepted alternative.

This is not the sort of design problem that truly hampers my ability to recommend them to most users but is definitely very puzzling when looked at on a grander scale.

Comfort and Isolation

Due to the RE-ZEROs being so similar in design to the RE0s, the level of comfort and isolation is almost exactly the same across both IEMs. The RE-ZEROs are among the most comfortable IEMs I’ve used, especially when worn over the ear and when using Sony Hybrids. The stock small bi-flanges provide a relatively comfortable fit for my ears as well. The RE-ZEROs are ported on the rear but that doesn’t seem to adversely affect isolation too much and the resulting levels of isolation are about average.

Microphonics are definitely present and can be bothersome while in motion but are mostly unobtrusive and can be toned down considerably by using the included shirt clip and wearing the IEMs over your ears.

Of course, all that has and can possibly be said about comfort and isolation will inevitably vary from person to person so keep in mind that your mileage may vary.

Sound Quality

Burn in: These IEMs were given upwards of 100 hours of burn in time prior to review.


  • 60GB iPod Video 5.5G – Fiio L3/Canare Cable LOD – CMoy BB v2.02
  • 16GB iPod Touch 2G
  • Lenovo Ideapad Y450 – 3.5mm interconnect – CMoy BB v2.02

Various music files including 128kbps – 320kbps MP3 as well as 16 and 24 Bit FLAC files.

Given my history with the RE0s, I had very high expectations of the RE-ZEROs. The RE0s are, at least in my opinion, among the best values in portable audio today and this is certainly a lofty goal to live up to, to be sure.

Starting at the bottom, the RE-ZEROs have a slightly weightier low end than the RE0s.While the level of bass is still a bit light in the grand scheme of things; I found it to be quite adequate, even for the Hip-Hop and Rap tracks that are so heavily featured in my usual rotation. The RE-ZEROs exhibits a certain smoothness, definition and refinement that I prefer to the heavy, thunderous bass tones that are so common in “mainstream” sorts of sound signatures. Extension is quite impressive, even if there is a slight rolloff as you reach the deepest of sub bass levels.

The RE-ZEROs possess a full and almost liquid smooth midrange, a far cry from the relatively thin and recessed midrange found on the RE0. The midrange sits at the forefront of the sonic presentation and vocals, both male and female are well defined, full, rich and mostly pleasant to listen to. I say “mostly” because the RE-ZEROs are prone to a bit of sibilance and sharpness in the midrange. What I mean by that is the sounds of pronounced “t” sounds, the hissing sounds of “s” enunciations and the crack of snare drums are a tiny bit exaggerated with some sources and I noticed this especially on my iPod Touch. I’ve found that I am somewhat sensitive to these sounds and the iPod Touch is a rather bright sounding player so this minor occasional sibilance may not be a problem for most users so I advise you to take this with a grain of salt.

Borrowing yet again from the audiophile dictionary, midrange tonality is best described as “sweet”. Put simply, aside from the minor vocal sibilance I mentioned earlier, there is practically nothing I can say negatively about the midrange. Instruments have a somewhat natural timbre and fullness that reinforces my opinion that the RE-ZERO’s presentation of the midrange is the best I’ve heard in an IEM and works very well with Rock and Alternative music because of it.

Treble is also presented differently than that of the RE0s. The RE0s are widely regarded as having one of the best high frequency presentations of any IEM and the RE-ZEROs are certainly not too far behind their older siblings in that regard. While the RE0s seem to have endless treble energy and present highs in a smooth and non-fatiguing manner, boasting impeccable extension, treble is handled slightly differently on the RE-ZEROs. Treble is more delicate and crisp, with a familiar smoothness but lacks the endless top end extension. The benefit of the slight treble rolloff is a lack of any sibilance whatsoever, at least not to my ears, even given my sensitivity to midrange sibilance.

The soundstage presented by the RE-ZEROs is both deeper and wider than that of the RE0s but not much. The soundstage is still relatively small in comparison to other IEMs such as the MEElectronics M9 but it does a good job of portraying intimacy as well as spatial positioning between instruments. Imaging is also quite good and while listening to some Jazz and Acoustic tracks, I was able to pick out the position of instruments placed around the stage quite easily and was seemingly enveloped by the sound. Whereas many headphones and IEMs tend to place you front row center, the RE-ZEROs seemed to place me right up on stage with the performers which I liked a great deal.

The kindred spirit shared by the RE0 and RE-ZERO is amazingly apparent to me listening to them side by side. The excellent transparency, clarity and balance inherent to the RE0 are definitely present in the RE-ZERO, albeit presented in a different manner. The RE-ZERO focuses less on the highs and more on the midrange and low end, two things that some users wished were presented better by the RE0s. Personally, I found the RE0’s midrange to be pleasing to my ears, even with it being slightly recessed and the RE-ZEROs are even more pleasing in that regard now that it has been brought forward. The slightly weightier low end is also a plus.

Now we get to the $99 question. Are the RE-ZEROs superior to their older siblings? To be frank, I don’t think so. What the RE-ZEROs represent to me is an alternative to the sound signature of the RE0s. Neither better, nor worse; merely different.

Value and Conclusion

As mentioned before, the RE-ZEROs are a 1000-unit limited edition that retails for $99 plus shipping. At this price point, I firmly believe that the RE-ZEROs are an excellent value for the money. The exceptional clarity, detail, smoothness and natural presentation offered by the RE-ZEROs is well worth the asking price and these IEMs, like the RE0s, perform well above their price point. Seeing as these are a limited edition and are a mere $20 price hike over the RE0s, I’d recommend going for the RE-ZEROs if you’re debating picking up one of the two. Despite some minor design quibbles, mostly concerning the balanced plug, these are very easy to recommend and you might end up kicking yourself for not picking these up when you had the chance once supplies have run dry.

HiFiMan has impressed me once again with another stellar entry into their already very impressive catalog of products. I am certain that HiFiMan’s offerings will only continue to improve from here as new products are introduced and the brand name grows in popularity. Whatever the case, the RE-ZEROs are undeniably some of the most intriguing and high quality IEMs to be released in recent memory and you’d be hard pressed to find another earphone that can compete at this price point.

The RE-ZERO IEMs are available at Head-Direct for $99, while supplies last.

About Justin McBride

My name is Justin McBride and I’m a guy who enjoys writing, playing games and writing about playing games. Sound lame enough yet? Well, I have other interests as well such as hanging out with friends, watching TV, going to the movies from time to time, surfing the internet, listen to good music, drive at speeds I shouldn’t be driving at and so on. The problem is, that’s all stuff everyone likes to do, so why write about it? Oh wait, seems I just did. Oops.

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