Overlooked, underappreciated and unloved are all words that adequately describe the Hifiman RE600. While its lower-end sibling, the RE-400, received no shortage of accolades, the considerably more expensive and visually identical RE-600 very much fell into obscurity. It didn’t help that Hifiman’s higher end offering retained the same design shortcomings and longevity concerns despite the increase in price. But years later, Hifiman have balanced out their offerings, perhaps in the wake of the newly announced RE-800 and RE-2000, with the second iteration RE-600 bearing a considerable price cut and a vastly improved cable. But are these tweaks too little, too late? And is the RE-600 still a competitive buy? Let’s find out.
*The RE-600 initially launched with a $400 USD asking price. The improved V2 has since dropped to $200 USD and can be found for even less online. Of note, the RE-600 has a balanced 2.5mm termination for use with certain dedicated audio players while the RE-600S has a regular 3.5mm plug which suits smartphones, laptops and all other players.
I would like to thank Hifiman very much for providing me with the RE-600 in exchange for my honest review. There is no monetary incentive for a positive review and despite receiving the product free of cost, I will attempt to be as objective as possible in my evaluation.
About Me, Background, Gear of choice, Preferences and Biases –
I generally prefer a u-shaped sound that is close to neutral. I like a lot of detail and clarity but can appreciate a smooth, laid back sound. I’m not particularly treble sensitive so I may be more forgiving of brightness over darkness. I will note if I use a different eartip/pad/cover during the review and describe the sound changes.
The RE-600 V2 comes identically packaged to the original model with the same extravagant faux leather box and accessory suite. The lightly padded leather contrasts to the chromed RE-600 plate, all crafting an air of premium quality.
The top cover magnetically opens to reveal the RE-600 while the bottom contains the eartips and cable winder. Some papers, extra nozzle filters and a hard carrying case are packaged separately due to popular request. Unfortunately, the carrying case is quite average, poorly sized and frankly cheap feeling.
I suppose it’s because a case was never meant to be included with the RE-600 though even the cheap zippered unit is better than nothing. The included eartips are similarly of questionable quality, a few of mine had forming issues and most were strangely sized. Rather than including small, medium and large sized tips, Hifiman equip the RE-600 with a medium dual-flange sized tip and only include considerably larger tips in the box. Strangely, the pre-installed tips are also made from a different silicone than the others though I found the stock dual flanges to provide the best combination of comfort and sound quality anyway.
The RE-600 is almost identical to the RE-400 in size and shape with only the piano black finish and improved cable differentiating between the two. The RE-600 looks subjectively more premium though I do prefer the matte texture of the bare aluminium RE-400, the gloss finish can diminish in-hand feel though this is hardly relevant when in the ear. And honestly, I’m glad that Hifiman decided to stick with the same design because it is exceptional in almost every way.
The RE-600’s ergonomic advantages begin with their minute housings that are even smaller than the already tiny ie800 and magnitudes smaller than the Pinnacle P1 and 1More Quad-Driver. The cylindrical housings are just 7 millimetres in diameter with some fluting to enable the use of slightly larger drivers. The housings are entirely aluminium but remain essentially weightless due to their small dimensions. Their gloss black finish is even and the earphones feel pretty well finished though they still pale in comparison to meticulous build on the 1More Quad Driver. The rear face exposes the silver metal underneath with a concentric texture adding some visual intrigue. Hifiman apply a clear coat over the exposed metal to prevent scratches though mine still suffered from a few nicks during daily usage.
The earphones have average sized straight nozzles that will fit most tips out there such as the Sony Hybrids and Spinfit Cp100s. The RE-600 was designed for a deep, cable down fit though due to their very laterally placed strain reliefs, they also fit perfectly over-ear (I preferred to wear them over-ear to reduce cable noise). Either way, the RE-600 is perfectly comfortable for long-term listening, one of those earphones that disappear in the ear, and provides great passive noise isolation, just less than the fully sealed monitors from Shure and Westone. They are perhaps the smallest, most isolating dynamic driver earphones I have ever tested. When paired with foams, the RE-600 easily suffice for any kind of travel including air travel. Fit stability is also fantastic and the earphones easily stay put during my usual 6km run without requiring adjustment, they are just as isolating and stable as most sealed monitors but are far more comfortable long-term. They are quite low-profile during when inserted though side lying is still not ideal due to the shape of their housings.
As stated by Hifiman, the main change with the RE-600 V2 is its improved cable, both in terms of build and sound, seeking to address the primary shortcoming of previous Hifiman models. The new cable is a silver plated copper unit with a smooth texture above the y-split and fabric weave beneath. Unfortunately, the cable is still fixed though the inclusion of any kind of connector would not be possible due to the earphone’s size. That being said, the included cable is of pleasing quality and feels far sturdier than most. Strain relief on all terminations, especially the jack and earpieces are exemplary and I have confidence in their longevity; I actually prefer having a solid fixed cable over the ergonomically flawed semi-replaceable unit on the ie800. The cable is essentially silent when wearing the earphones over the ear and never catches on clothing during commute due to its smooth texture. It is a bit stiff, especially above the y-split, with more memory than I would like though it isn’t springy and rarely tangled during my use. Thickness is on the beefier side, around 30% thicker than the cable on the RE-400 which is fantastic. The straight 3.5mm plug is quite low profile but will not fit into thicker phone cases due to a lack of any offset. Overall, I am content with the RE-600 V2’s cable, it is hugely improved over the thin, rubbery unit on the RE-400 and RE-600 but ergonomically, the cable still falls short of the brilliant Meeaudio MMCX cable and even the super tangle resistant 1More cable.
Utilising a single dynamic driver, it’s easy to dismiss the RE-600 as over-priced for what is on offer. But in reality, it’s the quality of that driver and surrounding acoustics that really matters, much more so than the complexity of the driver array itself; the Sennheiser ie800 is a fitting example. And while hybrids and multi-armature earphones have all become commonplace around this price point, I actually find myself preferring single dynamic driver earphones in a number of scenarios. The RE-600 exemplifies my beliefs with a midrange that one could almost mistake for a BA earphone mated to a lovely extended bass response and smoother treble that avoids the sharper tones that can affect some BA’s. Of note, the only sonic differences on the new RE-600 V2 over the original can be attributed to their new SPC cable, the drivers and housings have remained unchanged.
While I’m not the biggest believer of burn-in, there is no doubt in my mind that the RE-600 has undergone change in one way or another. Out of the box, the RE-600 sounded quite dry and their midrange was unnatural. While a lot of earphones sound the same out of the box or experience small changes relatively quickly, the RE-600 did require a lot of burn-in, around 200 hours before I noticed any changes at all. By the time I got around to the full review, my RE-600 had over 300-hours of burn-in and sounded perfectly natural and extended in either direction. I also rolled a few tips looking for a little extra low-end and found the Spinfits and Sony Hybrids to provide that little extra warmth. However, both also had a negative effect on the midrange so I ultimately stuck with the stock dual flange tips as they were the most linear and natural sounding to my ear.
The term balanced gets tossed around a lot in reviews but few earphones are described as being neutral. Because neutral is so similar yet so different to balanced; while I would call an earphone like the New Primacy or Campfire Andromeda balanced, they are most certainly not neutral in any way. And that’s because neutrality isn’t always ideal, balance enables room for sculpting and personalisation whereas neutral is thought to be derivative of a tool as was the original Etymotic ER4. But with neutrality comes many benefits, namely transparency, consistency and resolution. The RE-600 is almost ER4 neutral but with better sub-bass extension, a little more deep bass presence and a smoother high-end. This actually makes it very difficult to appreciate the RE-600 because they don’t leverage clarity and aggressive high-frequencies like the ER4 and Grado GR10E to justify being so lean. Instead, the RE-600 is smoother and more laid-back, how they can be so forward and laid-back at the same time escapes me, and though it provides an unorthodox listen, the RE-600 has all the technicality I could wish for.
They can sound anaemic on first listen, but one can quickly acclimatise to their sound, especially if you’re coming from an already leaner earphone. Their stunning transparency and great end to end extension also mean that they respond very well to eQ, and it was evidently a conscious choice on Hifiman’s behalf to make them sound this neutral and lean. I do feel that the RE-600 is actually slightly mid-forward though bass and treble never become overwhelmed in any way.
The RE-600 has a fantastic soundstage considering the size and nature of the earphones sound though the outstanding 1More Quad Driver possesses more space and separation while the Pinnacle P1 is wider in presentation. The RE-600 has a well-rounded presentation with very good width and depth but just average height; though few earphones around this price really excel in this regard. Imaging is the RE-600’s speciality, they are one of the best performers I’ve ever heard with regards to instrument placement and centre image at any price. When listening to Bigbang’s “Last Dance”, vocals were appropriately diffuse without sounding distant while guitar strums and atmospheric effects were all perfectly placed with exceptional layering and plenty of space. By comparison, the RE-400, Pinnacle P1 and even 1More Quad Driver all provided considerably vaguer responses. Separation is very impressive, not quite Quad Driver impressive, but easily on par with the Pinnacle and other similarly priced earphones despite the RE-600 being the most mid-forward. It’s the soundstage that really prevents the RE-600S V2 from sounding over forward and fatiguing, it is far superior to the Etymotic ER4 in terms of space while retaining that razor sharp imaging, making the RE-600S the endlessly more listenable daily earphone.
Despite the RE-600 originally being designed for Hifiman’s dedicated balanced sources, the RE-600S V2 is very easy to drive from essentially any source. With a sensitivity of 102dB and an impedance of 16ohms, the RE-600S V2 reaches dangerous volumes from portable sources and is more impervious than most to hiss. They were driven fine from my iPod Nano 7G and HTC 10 with my Oppo HA-2 and Fiio X7 providing minimal benefit. In fact, due to their rather immaculate transparency, the RE-600S V2 finds better synergy with warmer, more musical sources over analytical ones, and the slightly fuller X5 III and HTC 10 both provided perfect pairings. They don’t require an external amplifier but scale very well, again due to their transparency, and they are without a doubt one of the most revealing earphones I have heard, despite not being the most technical or analytical.
The RE-600S V2 is very neutral in the bass department with a slight emphasis on deep and sub-bass. They are completely devoid of flab or bloat and bass speed is comparable to any armature-based earphone. That being said, they also have a lot more sub-bass than the vast majority of armature earphones, even those costing many times more. Once adjusted to their lean low-end, I quickly realised that the RE-600S V2 isn’t missing out on any low-frequency information with great sub-bass reach and nice rumble. They don’t have the same bottomless bass response as the ie800 or larger dynamic driver earphones like the cheaper Fiio F5, but they do provide a nice sense of moving air when the track calls for it. Being as transparent as they are, bass really gets out of the way when not called for and the earphones can sound quite thin with certain material. On the flipside, the RE-600S V2 has the ability to sound very full and warm, once again, when the track calls for it. As a result, the RE-600S is not always the easiest earphone to listen to and they don’t sugar coat your music like a lot of earphones out there, but if you’re looking for fidelity, you will find plenty to love here.
Of course, isolated comments fine, but it’s in comparison to class leading earphones in different price ranges that the relative performance of the RE-600S V2 becomes apparent. From the outset, Hifiman’s highly awarded RE-400 presents as the most pertinent comparison and though the two don’t vary much in tuning, the quality of the RE-600’s sound has been universally improved. Within the low frequencies, the RE-600 is instantly more deep bass focused than the RE-400, though the RE-400 has more mid-bass, sounding fuller as a result. When listening to Red Hot Chilli Pepper’s “Soul to Squeeze”, bass notes on RE-600S had more of a sub-bass focus, bass had more depth while the RE-400 sounded slightly fuller and more punchy. Bass notes had more texture on the RE-600 despite having slightly less emphasis and bass resolution was appreciably improved. I also found comparison with the GR10E to be intriguing as both earphones pursue a similar sound yet the Grado has maintained its initial $400 asking price; so let’s see if that retained value translates to a similarly timeless audio performance. Being a single BA earphone, the GR10E lacks the bass depth and sub-bass fullness of the RE-600, although its single moving armature driver grants it with very impressive end to end extension. Listening to David Bowie’s “No Plan” revealed that the RE-600S manages more sub-bass solidity and a little more texture in the low-end. The GR10E had a punchier mid-bass performance that was still without a hint of bloat or flab; it was also admirably nimble and tactile, handily matching a lot of multi-armature earphones. The GR10E did have a little more bass definition though both resolved similar amounts of nuance and texture.
Hifiman has always impressed me with their midrange tuning, and its good to see that their expertise with open headphones has transitioned well to the in-ear form factor. It was actually within their midrange that the RE-600S drew parallels with the RE-400 and Grado GR10E with the RE-600S providing a nice middle ground between the warmer RE-400 and brighter Grado. The RE-600 unsurprisingly has more similar tuning to the RE-400 though subtle tweaks in all areas bring the tonality closer to neutral reference while improving upon resolution, transience and texture. The RE-600 is a slightly mid-forward earphone with very revealing and neutral bodied mid tones that makes the slightly thicker, warmer RE-400 sound lacking in resolution and detail. The RE-600 also has more midrange clarity partly due to their more forward presentation though they still don’t quite sound as glossy as the more sculpted earphones around this price like the 1More Quad Driver. The RE-600 is also an exceptionally coherent earphone, more so than the RE-400 due to its superior staging performance, with improved vocal layering, background detail and separation. The RE-600 is very detailed despite not being particularly aggressive, with similar retrieval to class leaders like the Pinnacle P1.
But coming back to the RE-600’s initial $400 asking price and comparison is not quite so single sided. While they comfortably compare to the very best $200 earphones out at present, the RE-600S V2 still lacks that extra layer of technicality possessed by more expensive earphones. To reinforce my point, I’ll draw comparison back to the $400 Grado GR10E, released around the same time. Immediately, the GR10E provides a surprisingly balanced listen for a Grado product; it is definitely one of my favourites from the company. The Grado maintains tinges of that signature Grado sound with a slightly brighter tonal tilt and a plethora of midrange detail, definition and resolution. Though the RE-600 is a very clear and resolving earphones, the GR10E is clearer yet and slightly more resolving at the cost of sounding slightly thin and raspy throughout. The RE-600S sounds more natural with more body to vocals but also less overall clarity. And though they are more accurate in this regard, the hyper clear GR10E really flatters female vocals and accentuates their sublime resolution and detail retrieval. On the contrary, the more linear RE-600 is more consistent with most instruments and male vocals do tend to sit slightly behind on the GR10E, where they are more balanced on the RE-600. The GR10E is also a little dry in the lower mids while the RE-600 proves to be more natural and coherent. Considering that I prefer brighter earphones, it’s no surprise that I bias the GR10E though, at their reduced price, the RE-600S represents terrific value with only slight compromise on quality while holding some advantages in tuning.
Despite their lean bass response and linear midrange, the most polarising aspect of the RE-600S V2 will likely be their treble tuning. As aforementioned, most lean, neutrally tuned earphones like this tend to have aggressive treble responses that provide awesome clarity and detail uninterrupted by their leaner low-end. However, the RE-600S V2, despite their new silver plated cable, is instead quite smooth and laid-back with slight roll-off at the very top truncating some high notes. So like the Fiio F5, they do lack that instant wow-factor though longer term, they prove to be just as revealing while being vastly less fatiguing; As much as I love the GR10E, I wouldn’t listen to them all day for instance.
When listening to Radiohead’s “High and Dry”, treble notes on the RE-600S were notably more resolving than the RE-400 though the RE-400 does have a little extra emphasis that the RE-600 does not possess, making the RE-400 sound more vivid and dynamic. That being said, the RE-600 doesn’t sound particularly dark due to their great detailing and resolution and the RE-400 does sound more granular by comparison. The Grado’s are interesting in that they create that vivid and endlessly revealing treble response without succumbing to grain or harshness. This was most evident when booting up Nirvana’s “Lithium”, a very treble heavy song which can sound downright crunchy on some earphones, especially those with any kind of middle treble emphasis; fortunately for me, neither the RE-600S nor the GR10E provided an ear-splitting rendition. The GR10E immediately impressed with fantastic extension, detail retrieval and air. The RE-600S was a little rolled off in the high-end, especially audible in comparison to the GR10E, with treble notes being pushed back a little by comparison and higher details were less crisp and aggressive in their presentation. The high end on the RE-600 is definitely on the more laid-back side despite the upper midrange being quite aggressively detailed whilst the GR10E is quite aggressive all the way through. As a result, the RE-600S is smoother throughout though the GR10E is more separated and considerably more open.
While the $99 RE-400 broke headlines with its value for money, the RE-600 is not to be seen as overpriced or underperforming in any way. While it doesn’t sound as engaging and dynamic as most of the earphones that we have come to consider balanced or impressive, when attuned to the RE-600’s mellow and delightfully linear tuning, all those earphones come off as unnatural and sculpted. I don’t mean to hype up the RE-600, it’s not a new earphone nor is it a flawless one, but I do think it has been severely underappreciated and misunderstood in many ways. Because at the end of the day, the RE-600 is an incredibly versatile and natural sounding earphone with ergonomics that are nothing short of outstanding. Sure, I would prefer a little more treble extension and perhaps a smidge more midrange clarity, but the RE-600 carries that neutral balanced armature sound pioneered by the original Etymotic earphones without compromising sub-bass extension and soundstage size.
But if you don’t understand the audiophile jargon, our bias towards neutral earphones and love for transparency, but have stumbled onto the RE-600S V2 anyway, I should warn you that this earphone is most certainly not for you, nor was it really designed for a consumer market. The RE-600S V2 competes very well with earphones like the Quad Driver and Pinnacle on a technical level though those will definitely serve many listeners much better with their more polite tuning. I’m not downplaying the RE-600 here in any way, simply stressing that impressive technical performance doesn’t always translate to an impressive listen and while I think everyone can appreciate the RE-600S V2, I’m not sure everyone can enjoy it.
Verdict – 8.5/10, If there’s one advantage the RE-600 holds over other earphones, it would be consistency; they perform so predictably with every genre, vocals, in particular, always sound exceptionally lifelike and natural. So don’t let the leaner, more laid-back tuning turn you off because extended listening reveals that the RE-600 has all the resolution and fidelity we are all looking for in this hobby. They haven’t aged since their inception, rather the RE-600 has matured with more modern earphones lacking the refinement and restraint of Hifiman’s classic offering.