Sound Analysis.

RE2k has a mildy v-shaped sound signature with a neutral-revealing tonality. Depending on pair up with different sources, I noticed the signature can flip flop between being slightly v-shaped to a more balanced. The sound is more on a revealing side, but it’s not too bright or harsh, and not of an analytical quality. I didn’t take as good notes with my impressions out of the box, but do remember treble being brighter and crisper, closer to a threshold of my tolerance.

After 200hrs of burn in, the lower treble settled in and the bass quantity improved. The mids are still pushed slightly back, and perhaps it’s just a perception of the relative lift in mid-bass and treble, but as I mentioned before – the presentation of mids slightly varied with different sources, where in some cases it was more balanced. The bass is authorative but not overwhelming, and treble is revealing, but not shrilled. I also want to note that I’m using Symbio hybrid eartips which have a silicone lining with a foam filling, so I get a decent seal and the bore opening is slightly narrowed down relative to the nozzle diameter.

Starting off with a low end, you have a deep sub-bass rumble, visceral, textured, layered, with a slight elevation but not overwhelming. This is a pure analog sub-bass, like you would hear in floor standing speakers. Surprisingly, it’s layered enough to be easily distinguished from mid-bass which has a nice impact with an average attack and decay, just enough to keep it under control and separated from lower mids.

Lower mids are not too thin or too thick, have a neutral body and absolutely no veil or muddiness. Upper mids are clear and detailed, with a nice balance between being revealing and having a natural tonality, though a little on a colder and thinner side. They are not as airy or layered, and miss some microdetails, but the focus here is on being balanced without being too thick or too revealing. As mentioned already, overall presentation of vocals is pushed slighted back, not too far back, thus my reference to “moderate” v-shaped sig.

Treble is crisp, well defined, more on a brighter side, but without a hint of sibilance. The infamous 5k-6k peak is kept under control, while you have more clarity and definition thanks to a peak between 9k-10k. I hear a good level of airiness, but the treble extension doesn’t go too far.

The soundstage has a very impressive width, and a nice depth, not too deep or holographic, but in an elliptical shape, expanding wide and a few rows in front of you. Along with this expanded soundstage, the imaging also has a good placement of instruments and vocals. At least to my ears they have a convincing positioning.

While I can easily distinguish most of the instruments and vocals and the sound is very clear and detailed, not congested at all, I don’t think RE2000 has the best layering and separation where I don’t hear as much air between the layers of the sound.

Comparison.

RE2k vs Fourte – RE has a wider soundstage with more depth; both have a very impressive low-end performance with a deep textured sub-bass rumble and analog quality mid-bass with a strong punch, though RE bass is a touch faster. Lower mids are more neutral in RE while Fourte has a little more body. Upper mids is where I hear more difference with Fourte being a little smoother and more natural, while RE is brighter and thinner. Both have a very revealing upper mids, but Fourte sounds just more natural in comparison. When it comes to treble, they flip with Fourte being crisper and having more airiness. But overall, these two are not too far apart (in my Fourte review this comparison was slightly different, and only later I realized that RE2k treble became smoother after more mileage).

RE2k vs Xelento – both have a very similar soundstage width, while RE has more depth, extends further; X has a deeper sub-bass and more mid-bass impact, while RE has a slight boost but nowhere near the quantity as X, while the quality is similar, just scaled down. RE lower mids are leaner, right around the neutral level, while X is a little north of neutral with more body, but not too much. Upper mids in X are smoother, more organic, more balanced, while RE upper mids are thinner, more revealing in comparison. With treble, both have a well-defined treble, but RE is crisper.

RE2k vs RE800 – RE soundstage is wider in comparison to 800, but both have the same depth. Both have a similar level of bass impact, though RE goes deeper, but due to a more forward mids in 800, it creates a perception that RE has higher bass quantity which I don’t think it does. Both have a well-controlled bass, with a faster than usual attack of the dynamic driver and not a very long decay which gives enough room for lower mids. Due to a more balanced sound on RE, bass has a better presentation and sound a little more articulate to my ears. Lower mids are neutral, not thin but at the same time not contributing too much to the body of the sound (lean). Upper mids have similarly, but toward the lower treble RE smooth out with a more natural tonality while 800 becomes harsher and a lot more revealing. RE upper frequencies are not exactly warm and fuzzy either, but relative to 800 they are a lot more smoother and more natural. Both have a crisp well-defined treble and good extension but 800 pushes more toward sibilance and has more airiness.

RE2k vs Andromeda – RE soundstage is a little bit wider, while Andro staging extends a little deeper. Both have an extended sub-bass rumble that goes deep, but Andro’s mid-bass has more impact, hits harder. Both have a relative similar attack of the bass, maybe with RE being a little slower, and the bigger difference here is a decay, shorter in Andro which is more typical for BA drivers, and a little longer with RE, making a smoother transition into mids. Both have a well-controlled bass, though Andro is more articulate, with sharper details, while RE is more analog sounding. When it comes to lower mids, tables turn around with RE being more neutral and leaner while Andro being north of neutral with more body. Upper mids in both have plenty of clarity and transparency, but RE is a little smoother more natural versus Andro being a little more revealing and grainier, which also spills into lower treble where with some songs Andro can sound a little harsher in comparison to more natural RE. Don’t get me wrong, Andro is not as bad as RE800, but in relative comparison to RE I found upper mids/lower treble harsher in Andro.

RE2k vs K10UA – RE soundstage is wider and extends deeper, while K10 has a more intimate staging in comparison. Both have a similar sub-bass extension, with K10 having a little more mid-bass impact and having a faster punch with shorter decay, while RE is a little more analog and relaxed in comparison. Both have well controlled bass without spilling into lower mids. Lower mids are neutral in both cases, but RE is a little leaner while K10 having a little more body. Both have a lot of clarity and details in upper mids, though K10 is a little smoother with a bit more warmth. and the same with lower treble, both have a crisp well defined airy treble, but K10 is a little smoother in comparison to RE treble which is relatively thinner and brighter.

RE2k vs UE18+ Pro – RE is a touch wider in staging, while both have the same soundstage depth. RE sub-bass goes deeper and has more texture, while UE has a fast punch with a little more impact. Also, UE bass decay is shorter, more typical of BA driver performance, while RE is a little longer more analog smoother transition to lower mids. Lower mids are neutral in both IEMs, but RE is leaner while UE has a little more body, giving the sound a little more warmth. RE upper mids are brighter and colder in comparison to UE more natural smoother upper mids. But at the same time, RE is more detailed due to a more analytical nature of its upper frequencies. With treble, both are crisp and well defined, but UE is more natural and smoother in comparison to a brighter RE lower treble.

RE2k vs VEGA – RE is a little wider while both have the same soundstage depth. Both have a deep sub-bass extension, though VEGA has a more boomy sub-bass quantity. The same with mid-bass, where VEGA has a lot stronger and more aggressive punch, while RE sounds almost neutral in comparison. Both have neutral lower mids with a more natural organic upper mids. As a matter of fact, both have their mids pushed slightly back while low end and treble lifted. The big difference is in VEGA having a much harder bass slam and brighter thinner treble, while RE bass is more balanced and less aggressive and treble which is crisp and less harsh in comparison.

Pair up.

Here is how I hear RE2k pair up with various sources in my review collection. In this test, I was using 1960 4wire cable. In every pair up, there was no audible hissing, but due to 60 ohm impedance with 103dB sensitivity, I did have to push volume a little harder.

Plenue 2 – expanded soundstage, deep sub-bass rumble and punchy mid-bass, smooth detailed mids, crisp well-defined treble, moderate level of airiness, nice transparency and layering.

LPG – expanded soundstage, deep sub-bass rumble and a little stronger mid-bass punch, smooth detailed mids, a lot crisper treble, still well defined, but a lot crisper, pushing 6k peak a little harder.

Opus#2 – expanded soundstage, deep sub-bass rumble (nicely textured), strong mid-bass punch but not too overwhelming; mids are still pushed slightly back, but very natural and detailed. Treble is crisp and well defined with a nice level of airiness. The overall sound is more transparent, a little more revealing, and with improved layering and separation.

X7ii – expanded soundstage, deep sub-bass rumble with a little more quantity, mid-bass has a nice punch, mids are more balanced, clear and detailed, still smooth and natural, treble is crisp and well defined, with a little more airiness. Overall sound is a little more balanced, especially mids.

DX200 – expanded soundstage, deep sub-bass rumble with a nice punchy mid-bass, detailed natural mids, crisp well defined airy treble. Mids are more balanced, very transparent, layered, and the sound has an excellent separation.

AK120ii – expanded soundstage, deep sub-bass rumble with a nice punchy mid-bass, detailed natural mids and very crisp treble with a nice level of airiness. The sound is mildy v-shaped, with a nice level of transparency and layering.

WM1Z – expanded soundstage, deep textured sub-bass rumble with a very articulate mid-bass punch, balanced mids, very natural, detailed, realistic vocals, crisp well-defined treble with improved extension and airiness. The sound is more transparent, layered, well separated. This sounds like the most natural pair up in comparison to other sources.

Galaxy Note 4 (phone) – soundstage is still wide, but not as wide as with dedicated DAP sources; surprisingly I didn’t have to push my phone volume high enough, deep sub-bass rumble, surprisingly good extension, nice mid-bass punch, smooth organic balanced mids, nice well-defined treble, though not as crisp. Overall sound was more balanced, not as resolving or layered, but smooth, lush, detailed, surprisingly good pair up on the go with a phone.

Conclusion.

Finally, HiFiMAN has its own true flagship IEM, and in my opinion it’s definitely worth checking out! Single dynamic driver flagship design is tricky because you have to deal with limitations of using only one driver. But with utilization of Nano-particles coating tech, Dr Fang was able to lift some of this limitation while gaining extra control in sound tuning. Maybe RE2k does not have exactly the smoothest or the most natural tuning and it’s not very analytical, but its more neutral revealing tonality works quite well with many music genres and pairs up nicely with different sources for hours of fatigue-free listening even with sound being a little on a brighter side.

I did mention about RE800 in the intro of my review, which suppose to have a similar Topology Diaphragm design implementation, but I couldn’t wrap my ears around its tuning due to a rather forward 7k peak. Not saying it’s a bad tuning because while it was definitely not my cup of tea, I found other people enjoying its forward treble energy, with some who didn’t mind applying the EQ. But RE2k hits closer home to my ears, which also made me realize that in the last year I became a little more tolerant to brighter sound. Either way, it’s great to see companies introducing a new tech, and trying to reinvent that old dynamic driver wheel. HiFiMAN definitely nailed it with this release.