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Head-Direct (HiFiMan) RE-ZERO

Head-Direct RE-ZERO 400x300.jpg
Reviewed Aug 2010


Details: Limited edition TRRS-balanced earphone from HiFiMan/Head-Direct
Current Price: $99 from (MSRP: $99)
Specs: Driver: Dynamic | Imp: 16 Ω | Sens: N/A | Freq: 15-22k Hz | Cord: 4′ L-plug + 3” TRS adapter (L-plug)
Nozzle Size: 5.5mm | Preferred tips: UE Single Flanges, De-Cored Shure Olives, Meelec M11+ Short Bi-flanges
Wear Style: Straight down or over-the-ear

Accessories (3/5) – Single flange (3 sizes) and bi-flange (2 sets) silicone tips, shirt clip, spare filters (5 sets), 3” soft balanced->TRS adapter, hard balanced->TRS adapter
Build Quality (4/5) – Shells are made of sturdy-feeling metal and identical to those used by the RE0 except for the dark silver finish. Long rubber sleeves protect the cable and the 3.5mm L-plugs on both the standard cable and soft TRS adapter are identical to the one used by the higher-end RE252
Isolation (3/5) – Above average and potentially higher with the right tips, typical for a sealed straight-barrel IEM
Microphonics (3.5/5) – Low when worn over-the-ear, and still not too bad when worn straight down
Comfort (4/5) – Housings are fairly small and light. Fit is quite unobtrusive in either configuration

Sound (8.4/10) – Released to commemorate the three-year anniversary of Head-Direct’s RE line of on-ears, the limited edition RE-ZERO is meant to be an easier-to-drive alternative to the slightly cheaper RE0 with a touch more bass. However, the most unique feature of the ZERO is the fact that it’s wired in a fully balanced configuration utilizing a 3.5mm TRRS plug for use with balanced amplifiers and sources. Not having a balanced source on hand, all of my listening was done in the usual manner (Sansa Fuze, iBasso T4, mini3) using the included soft adapter. Clearly Head-Direct delivered on two of their promises – the 16-Ohm RE-ZEROs are no more difficult to drive than many mainstream IEMs though they do have a bit of scaling headroom left over and they are, indeed, balanced.

Whether the ZEROs have more bass than the RE0, however, is open to interpretation. I have not heard the RE0s in a long time but still have a pretty good idea of how they compare to my CK10s, which have similar overall balance minus the low-end roll-off. For me, the difference in bass quantity and power between the RE0 and RE-ZERO is little more than barely noticeable – both lag behind the BA-based CK10 in quantity of impact, with the ZERO sounding slightly more filled-out. The ZERO is just as tight and punchy as the RE0s were with a low end that is slightly fuller but make no mistake – the RE252 is fuller still and the folks over at Head-Direct are in no way endangering their flagship with these. While very accurate and fairly detailed, the RE-ZERO presents bass (and indeed everything else) with a delicacy that is lacking in most of the competition and which may or may not appeal to the individual listener.

Moving on to the midrange, the RE-ZERO greets the listener with the usual clarity and detail of RE-series earphones. The mids are very slightly warm and transparency is good. The midrange of the RE-ZERO is generally extremely competent – I can’t call it forward or recessed, thin or full, wet or dry. I remember finding the mids of the RE0 a bit thin but the RE-ZERO has none of that. Like the bass and treble, the midrange lacks the satisfying crispness of armature-based earphones and sounds all the more relaxed for it. Harshness is also imperceptible to my ears all the way up into the treble. The treble itself is very clear and detailed but rather gentle as far as analytical earphones go. I remember the RE0 being quite effortless and energetic when it comes to treble reproduction and the RE-ZERO doesn’t really make me feel quite the same way – it is more like the RE252 in that regard. An interesting side effect is that the RE-ZERO is affected less strongly by the treble-taming qualities of open-cell (e.g. Comply) foam tips – welcome news for those who find silicone cushions offensive.

In terms of presentation, the RE-ZERO is again as competent as the RE0 but doesn’t quite run with the top-tier big boys. Its soundstage is only slightly bigger than average and while it does convey both intimacy and space well, it is not the best earphone for those who must be able to pinpoint the source of every sound in the soundscape. The somewhat relaxed presentation of the RE-ZEROs results in relatively hazy positioning despite good overall separation. One last thing to note is that I don’t consider the tonality of the RE-ZERO impeccably realistic compared to truly high-end sets – it reminds me a bit of a grayscale image in that regard – all of the detail is present and everything is instantly recognizable and yet confusing it with reality would take an effort.

Value (10/10) – The Head-Direct RE-ZERO is not an up-and-out upgrade over the legendary RE0. Instead, it is a somewhat more versatile take on the same design with a new-but-not-unfamiliar angle on the Head-Direct house sound. So what does the extra $20 buy over the RE0? Well there’s the obvious – pretty silver shells and a spot in the limited 1000-unit run of the earphone. There’s also the lower impedance, which reduces the power dependence of the earphones, if only slightly, and of course the possibility of running the IEMs in balanced mode should such an opportunity arise. Most important, however, is the sound signature. The RE-ZERO is clearly not designed to appeal to current RE0 owners as an upgrade. Those who were unimpressed with the RE0 or RE252 should probably keep away from the RE-ZERO as well. However, anyone who’s ever heard the RE0 and found them to be slightly too energetic or even piercing at the top or a bit too thin or laid-back in the midrange should like the RE-ZERO more. New users should likewise choose between the two sound signatures but keep in mind that the differences between the two earphones are quite minute.

Pros: Top-tier sound quality for mid-fi money; compatible with balanced amps/sources
Cons: Sound signature not for everyone, TRS adapter required for use with most 3.5mm jacks





Living in the fast-paced city of Los Angeles, ljokerl has been using portable audio gear to deal with lengthy commutes for the better part of a decade. He spends much of his time listening to music and occasionally writes portable audio reviews across several enthusiast sites, focusing mostly on in-ear earphones.


October 21, 2022


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