Dunu DC4 Custom In-Ear Monitor (CIEM) Review: 4-ways to virtue


Dunu DC4

DUNU is a fairly new company and was started as a brand of the Top Sound OEM making IEMs that utilize very high quality housings that have a similar look and feel, but better build quality to the Monster IEMs. I have had a chance to hear some DUNU products briefly, but as I now stick to custom IEMs and higher priced universals I didn’t perform a full evaluation. I was a little surprised when DUNU announced they would be releasing a custom IEM, although the move is not unheard of since custom IEMs have become much more popular as of late. I contacted DUNU and got in touch with Rocky, and after several emails were exchanges he agreed to send me a review unit.

Initially, all the information that was available was that DUNU was making a custom IEM with 4 BA drivers called the Custom 4 unit, so the anticipation was on. The price was unknown, but there were some amazing looking pictures on the DUNU Facebook page. While communicating with Rocky about the sample, I asked him about artwork and he responded that making sure the sound was right is the top priority and artwork is secondary, so maybe in the future. Considering they are just entering the market, I can’t disagree, and I do also agree that the sound is more important than the look. There was a lead time between when I sent my ear impressions and when the CIEM was sent.

In my communication with Rocky I found out the official name was going to be the DC4 and it will initially be limited to China. The price is around $500 USD in China and it is a 4 driver, 4-way custom IEM which for the configuration sounds like a great value. Of course, the actual value is dependent upon the performance, which I will get to within the review. This product is not available to my time of writing and I will update when publically available. Thank you Rocky for the opportunity to review the DC4.

How to Order, Warranty, Options

The DC4 is available through Stage 93 with an introductory price of $599 SGD (about $474 USD) while the regular price will be $759 SGD (about $600 USD).  Send them an email with interest. Stage 93 can only order 5 per month, so act fast!

Options: TBD.


The DUNU DC4 uses 4 balanced armatures in a 4-way configuration (3 crossover points) within an acrylic shell. There are three internal sound tubes that go to one larger sound tube within the shell, and the single sound tube extends to the end of the canal resulting in one large sound opening. The cables are detachable with a standard style connector, and recessed sockets are not available. The cable has a heat shrink sheath and the shell finish makes the shells smooth and slick.


The DUNU DC4 comes with a metal case similar to a metal UE TF10 case, but deeper. My unit actually came with two cases, and I was concerned the metal case wouldn’t fit my rather large shells as other cases have been too small, or borderline too small. The DUNU metal case did fit my shells just fine. The DC4 also includes a cleaning tool and soft cloth.


The DC4 came with a twisted cable covered in heat shrink which seems to be increasing in popularity. Rocky mentioned that other thinner cables had durability issues and the thicker cable fixes the issues. While the heat shrink adds a good deal of protection, it reduces flexibility and ergonomics when compared with a standard twisted cable, and the cable also exhibits microphonic. Beefy shell connectors appear to be made for recessed sockets although the DC4 doesn’t have that option. The cable has Chinese writing on it and Utopia in English. While I am not a huge fan of this type of cable due to the ergonomics and microphonics, the DC4 cable is better than similar cables I have experience with and you can’t argue with the desire for better durability.

Build Quality/Durability

With a pristine and beautiful shell, the DC4 is one of the best built CIEMs I have. Both the cable (see the cable section) and the shell appear to be high quality and durable. The cable is thick and this type of cable has proven to withstand abuse and last for quite some time. The shell fit and finish is very good and the coating on the acrylic makes the DC4 slick and easy to insert and remove without lubrication, reminding me of the Thousand Sound TS842.


Isolation is typical for an acrylic shelled custom IEM, scoring 5/10. With no music I can still hear most ambient noises, but at much lower volumes. When listening to quite music I can hear many louder ambient noises when listen, but when listening at moderate volumes I can’t hear much, such as my cell phone ringing right in front of me.


Quick reference: My review technique, Thoughts on reading a review, Custom IEM information

The DUNU DC4 received 100+ hours of burn in as is customary before I do my serious listening. I compared the DC4 with the Alclair Reference Master, Dream Earz aud-5X, Thousand Sound TS842, Fabs Fabulous Earphones, Minerva Mi-3, Starkey SA-12, and Wan Xuan i9pro.

Upon initial listen right out of the box I was somewhat impressed by the imaging and soundstage depth, although the soundstage was a good deal smaller than the Spiral Ear 5-way that I had been listening to for the days prior. I did think the dynamics were a little lacking, but after continuous play for a day, the dynamics improved. So when I started listening critically for my review I was shocked that I wasn’t as impressed with them as I was initially. After listening with various sources and comparing with various IEMs/CIEMs I realized the reason I was impressed and was not impressed has to do with the source, but I will cover that in the source matching section. This section will cover how the DC4 performs with higher end sources such as my modded iPod -> nice amps, HiFiMan 801, and Anedio D1.

Bass: Powerful, warm, and slightly enhanced would describe the bass. When a song doesn’t have a heavy bass presence you have to pull your attention away from the midrange, which is the focal point of the presentation, but with bass heavy tracks the bass will get your attention. Integration with the rest of the spectrum is excellent, performing very well in coherence across the spectrum. The capability of the bass is very good, nearly keeping up with the BA leader in the sub-$600 range, the aud-5X, which has a similar bass presentation to the DC4. There were often no or only minor differences between the two with many bass heavy tracks, but ultimately the 5X does have a bit better capability.

That said, the DC4 offers good detail, rumble, and power conveyance with nice texture and an overall good presentation that, as stated, matches with the rest of the spectrum. Compared to the dynamic drivers, the DC4 loses a bit of ground in the deep bass rumble, but is still impressive in its own right. Overall the bass of the DC4 is excellent given the price range and will please most people.

Midrange: The mid-forward and 3D presentation makes the midrange the focal point of the DC4 giving the midrange aspect of the music a sweet presentation, especially vocals. The DC4 is very dependent on the track that is playing and source presentations also play into just how good the DC4 vocals can sound. Midrange resolution, imaging, and detail levels are quite good resulting in a presentation that is immediate and engulfing. Clarity is one aspect of the DC4 that changes quite significantly depending on the track and to a lesser extent, the source, ranging from sounding nice and clear to a little on the thick side. While the DC4 will never be a clarity leader, the clarity can be quite good.

As good as the vocals are, the overall midrange presentation can get a bit congested and/or have a bit of a dark streak, which means the immediate, up front part of the presentation is clear, but there is a slight haze to the background sounds. This occurs mainly with lower end sources and is dependent on the tracks. Technical performance through the midrange for the price is very good leading to many competitors sounding like they lack midrange focus and depth. When paired with a good source, the midrange of the DC4 is a pleasure to listen to with a great depth and imaging, giving a great sense of realism.

Treble: Treble of the DC4 is sweet and very forgiving of poorly mastered and/or low bit rate tracks; however the detail levels aren’t quite up to most of the competition. Ultimate extension is good, recreating tones up to 17.5 KHz, but the treble starts to roll off a bit earlier than others in the price range at 14.5 KHz. However, if you want treble that is present, but never harsh, the DC4 will deliver with nice smoothness. There was never a time I thought the treble was peaky or harsh or fatiguing.

Presentation: Overall, the DC4 has a warm and rich presentation that is smooth but provides excellent detail retrieval at the same time. I would say this is unusual, but the Reference Master and aud-5X both do the same thing, but with different flavors. The DC4 is the smoothest of the three and the most forgiving, but also the most sensitive to sources and track variations. Bass remains fairly constant, but the midrange and treble presentations can change from clear to darker or congested. I would still call the presentation on the more analytical side, at least through the upper midrange compared to the ACS T1 for example.

The presentation has a good 3D quality to it when matched with a source capable of recreating a 3D space, with a mid-forward and up-close presentation that extends quite deep. Due to the depth and 3D presentation I never felt the DC4 sounded small except in direct A/B comparison, but due to the mid-forward presentation, it can sound more in the head than I am used to from many of my CIEMs. When tracks have been mastered in a mid-forward way they combine with the strengths of the DC4 resulting in a magical recreation of the music while more laid back and spacious recordings are slightly out of the comfort zone of the DC4. Technical performance is quite good for the price point in many regards including transparency, imaging, coherence, and detail while dynamics are a bit better than average. Clarity is middle of the pack but quite dependent on the source and track, as any good transparent CIEM should be. Speed is good as the DC4 beats more CIEMs in the price range than it is bested by. Attack is good and decay is excellent.


Dream Earz Aud-5X: Presentations between these two are different, with the 5X having a more laid back, wider, brighter presentation in contrast to the mid-forward sounding DC4. The smaller presentation of the DC4 is more coherent and focused with better imaging within the soundstage, but lacks the width that can be recreated by the 5X. Depth of the presentation is usually close, but the DC4 appears deeper due to the smaller width. Transparency is similar and track dependent as the 5X is more transparent with laid back and/or poor mastered recordings while the DC4 is with just the opposite. The 5X sounds a bit faster overall as the DC4 has a slightly thicker note in general, although the midrange of the 5X sounds thicker because of the more laid back presentation and similar midrange note presentation. While the DC4 is forgiving, the 5X is more forgiving of poorly mastered tracks.

Deep bass response between these isn’t too far off with the DC4 trailing by a bit in both rumble and quantity, however the 5X does have more punch in general (note that the canals of the DUNU are longer than the 5X). The 5X is warmer, resulting in a richer presentation that carries over into the midrange. While this warmth is nice for instruments like pianos, the carry over into the midrange does thicken it a bit, reducing clarity in comparison. The DC4 midrange is more mid-forward, cleaner, and clearer with better imaging. Overall, the vocals are more up close and personal with the DC4 making them more involving. Tonally the DC4 sounds more natural through the vocal range. The upper midranges of these two are relatively similar as they cross paths with the quantity of the 5X treble surpassing that of the DC4. Both have smooth and detailed treble, but the 5X treble does have more detail and articulation.

Both are technically very capable and will bring something different to your music. The 5X has a bit more bass capability and brightness with a laid back presentation in comparison that is more spacious while the DC4 is more mid-forward with vocals and has a more natural overall tone and better imaging. The 5X is more well-rounded with the ability to present a wider range of genres, but if you like acoustic presentations and want to pay attention to the vocals, the DC4 is fantastic.

Alclair Reference Master: The RM presentation is more laid back than that of the DC4, with a wider and more spacious presentation compared with the more mid-forward DC4. While the DC4 has a narrower presentation, the depth and imaging are superior to the RM, with more resolution within the presentation and slightly better instrument detail. Transparency of the DC4 is superior as is coherence while the RM has better speed and clarity. The DC4 is more forgiving of poorly mastered tracks.

The DC4 is more bass capable all the way around, with a richer and slightly more enhanced presentation that has deeper bass that is more reverberant. The RM does extend deep, but the bass presence isn’t what it is with the DC4, which translates up through the mid-bass. The mid-forward presentation of the DC4 puts the midrange in your face in comparison, but what you get is very sweet, smooth, and well presented. Due to the unforgiving nature of the RM treble, the comparison is very source dependent as the RM can have very sweet and detailed treble, but with less than great masters the DC4 treble is much easier to listen to.

Both are strong performers and somewhat similar. If you want a more laid back presentation with more overall space and better clarity, the RM is a great choice, but if you want a mid-forward presentation with very sweet vocals and bass capability, the DC4 is an excellent choice. Both can be used for listening to music, but the RM is more of a tool while the DC4 will be less fatiguing for everyday listening.

Thousand Sound TS842: With opposite presentations, the TS842 is V-shaped (enhanced bass and treble with a recessed midrange) while the DC4 is mid-forward these two give a very different sound. The TS842 doesn’t have all that much wider of a presentation than the DC4, but the depth of the presentation is quite different as the DC4 has considerably more depth with better imaging and resolution of space. Instrument detail, however, is better with the TS842. There is also a stark contrast to the presentation of the midrange on up as the TS842 has a sharper, more analytical presentation to go along with more speed. Due to the enveloping, 3D performance and more coherent presentation, the DC4 has better transparency and is a good deal more coherent than the TS842 in large part due to the dynamic/BA hybrid design of the TS842.

For a dynamic driver, the TS842 doesn’t flaunt it with enhancement, but it does show its capability when deep bass rumble is needed. However, the DC4 isn’t blown away and actually has more enhancement without losing much in ultimate capability except in the deepest registers where the TS842 is quite capable. As the mid-bass starts to build toward the midrange of the DC4, the opposite happens with the TS842, as the bass slowly tapers off toward the midrange, which is recessed and rather flat sounding in comparison. Treble of the two is quite opposite, with the TS842 having an enhanced, detailed, and analytical treble compared with a fairly balanced and smooth treble.

Going different directions, these two are compliments to each other, with the TS842 giving a V shaped frequency response and analytical presentation while the DC4 provides an inverse V (mid-forward) presentation that is smooth. The DC4 has better imaging and depth to the presentation while the TS842 bass rumble is superior even though the bass is a bit more subdued overall.

Fabs Fabulous Earphones: With a more laid back, lighter sound, the half-shelled Fabs offer a different sound experience than the DC4, which is more powerful, up-close, and personal. Soundstage space is about the same size even though the DC4 is more mid-forward, while the DC4 has a bit better imaging and instrument separation. Resolution/detail, speed, dynamics, coherence, and transparency are all better with the DC4, although the clarity and natural tone of acoustic music sounds a bit more convincing with the Fabs. The DC4 has a smoother presentation, especially in the treble region.

Bass is very divergent as the DC4 is very capable while the Fabs lack reverb, in part due to the half shell configuration. Much more power is conveyed from the DC4 up through the mid-bass, giving the DC4 more warmth and a richer presentation. The mid-forward presentation of the DC4 is in contrast to the Fabs laid back midrange, and the treble of the Fabs starts to relax in comparison with the more forward and prominent treble of the Fabs.

The Fabs sound like they are made for classical music and laid back light acoustic music, where they shine while the mid-forward DC4 compresses those genres in comparison. However, for most other music, especially vocal music, the DC4 is more involving. Technically the DC4 outperforms the Fabs, but sound signature, music choice, and fit/function should be the main considerations if you are choosing between these two. Although the half-shell design of the Fabs is interesting.

Beat Audio (Wan Xuan) i9pro: These two are fairly close in tone and frequency response, although there are differences. Spatially, the i9pro has a wider and more overall spacious sounding presentation, although the DC4 does have a good depth to the presentation and a slight advantage in internal resolution, instrument separation, placement, and imaging. The more liquid i9pro is more coherent but the DC4 has better clarity and transparency with a slight edge in detail levels. Both are similar in speed while the i9pro edges out the DC4 in dynamics and tone.

Differences in the bass region range from minimal to substantial depending on the track, as the i9pro has a greater capability to recreate tactile sub-bass even though the DC4 performs well in the bass region. Bass of the DC4 sounds a bit more controlled than the i9pro, although the i9pro does have more bass enhancement that is noticeable with bass heavy tracks. The midrange diverges with the DC4 becoming more mid-forward and giving a smaller yet more personal and 3D presentation. The upper midrange of the DC4 is more pronounced, giving a brighter sound that carries on through the treble. Both have somewhat similar treble response, although the i9pro rolls off a bit earlier and a bit faster, but the i9pro treble is a bit more resolving.

With similar presentations, the brighter and more mid-forward DC4 has an advantage in detail, clarity, and transparency while the i9pro is more capable in the bass region with more expansive presentation space. Both are smooth, fun, and engaging in different ways. The choice will come down to what is most important to you, a sweet, mid-forward midrange or thumping bass with a smooth and spacious presentation.

Minerva Mi-3: Mid-forward meets mid-forward with different twists. The Mi-3 has a very interesting projection of sound that puts you further away from the sound than all but one CIEM I have heard, which makes the DC4 sound very close and personal in comparison. Speed, transparency, coherence, dynamics, and resolution/detail are better with the DC4, but the Mi-3 has a bit better clarity with a slight bit more natural sounding tone. The Mi-3 is very liquid and makes the smooth DC4 sound rougher than it really is.

When you listen to the Mi-3 without any comparison, the bass seems capable as it extends and thumps, but when compared to the DC4, the bass is light, not having the same amount of body. The DC4 is warmer than the Mi-3, but the Mi-3 starts to thicken up through the midrange giving a richer presentation. The DC4 midrange is enveloping while he Mi-3 midrange is the focal point, but giving you space between the presentation and where you are located. The upper midrange and treble of the DC4 are both more prominent than the Mi-3, continuing the more up-close and personal presentation.

The Mi-3 has a pretty unique presentation that is very nice to listen to along with the liquid sound vs. the mid-forward and up-close presentation of the DC4. If you want bass reproduction, warmth and power, the DC4 is the easy choice, but both offer different strengths. While both can do any genre, the DC4 is a better choice for those with bass heavy, fast, or a wide range of genres while the Mi-3 excels at acoustic music that doesn’t rely on high levels of bass.

M-Fidelity SA-12: The SA-12 is a canal only CIEM with dual drivers and has a great, natural sound to it that is warmer than universal dual driver IEMs I have heard that use balanced armatures. In comparison, the DC4 really showed its technical dominance over the SA-12 with a warmer, richer, more detailed, and more transparent presentation. The SA-12 can keep up with a lot of CIEMs, but when the SA-12 was compared directly with the DC4 it just didn’t sound as good as I thought it would. This is due to the bass capabilities, natural tone, smooth yet more detailed sound, and larger but similar soundstage space, the DC4 makes the SA-12 sound a good deal lower in performance. With that said, the SA-12 is what I would consider a specialty CIEM due to the canal size of the shell for discrete listening.

EarSonics EM4: At over double the price, the EM4 has a similar sound signature, so I decided to make this comparison to see what you get for half the price. First, the EM4 has a noticeably larger presentation both in depth and width. There is more going on within the space that is created with better resolution of the soundstage to go along with more instrument detail. However, the DC4 does sound a bit deeper in general mainly due to the smaller width of the soundstage. With the right source, the DC4 images quite well and performance isn’t too far off. Clarity and dynamics of the EM4 are superior and the DC4 become slightly more congested with complex tracks. While transparency is close, the EM4 comes out ahead, but coherence is similar. Both are smooth and fairly forgiving, but the DC4 is more forgiving of poor tracks while the EM4 is more forgiving of laid back soundstage recordings given the mid-forward presentation (meaning that the EM4 will sound better when you play laid back tracks).

The DC4 bass is more neutral than that of the enhanced EM4, which can pump out much more bass with bass heavy tracks, however the DC4 sounds slightly better controlled. This isn’t something one would notice with the EM4, though, unless A/Bing. Warmth is similar, but the EM4 is slightly thicker in the mid-bass region. While these two are similar in midrange presentation, there are differences as the EM4 is in general more expansive and less forward. The DC4 sounds very involving with some tracks, and even more involving (but not technically better) than the EM4 in many tracks, but the EM4 presentation is more true to life sounding more often than not. The upper midrange of both are similar, but the lower treble of the EM4 has more presence than the DC4, which makes the DC4 have less propensity for fatigue. The EM4 is a bit brighter and more extended in the treble, but not by all that much.

Overall you do get a better monitor for over double the price, but the DC4 is still very enjoyable and never sounded bad from a technical perspective in comparison, although it did sound a bit too forward in some tracks. The DC4 is a good choice if you want a backup for your EM4 or want to plan your upgrade path to eventual purchase of the EM4. Of course, the DC4 will be a compliment to other CIEMs in much the same way the EM4 would be, but at a lower price point and with lower technical performance.

EarSonics SM3: Comparing from an onboard sound card in a PC I was surprised by how close these two performed. Sure, there were some sound signature differences, but the DC4 thickens up in the midrange with a lower end source. Using a high end source or a bright/cold source the DC4 takes the step ahead of the SM3 as was expected. The SM3 bass is punchy with triple flange tips, but the DC4 kicks the SM3’s butt in deep bass rumble and capability. The space of the DC4 is larger regardless of the source, but the difference is a good deal larger with a higher end source, and while the SM3 will retain an overall warmer/darker presentation, the DC4 can become slightly bright, with a good balance with the bass/midrange.

Clarity, focus, and dynamics of the DC4 leave the SM3 behind when a higher end source is used with both, and the DC4 disappears in comparison to the SM3. Switching to the SM3 from the DC4 results in a less than stellar sound and a desire to put the DC4 back in my ears. But, given the price difference, the performance of both seems in line.

Volume performance: The DC4 performs well at low volumes, especially when there is a powerful source. The bass driver kicks in and is dynamic at a moderately low volume. After turning the volume up past what I consider loud listening, although many may not, the DC4 starts to become rougher and congested sounding. Again, this is at listening levels that really aren’t necessary since the DC4 isolates well, and you will damage your hearing if you listen at those volumes for any extended period of time.

Sound Summary: The DUNU DC4 is a warm, powerful, and competent performer with a rich, natural tone that at the same time has an analytical nature to it. While this detail is not the best in the class, the mid-forward presentation and imaging bring the details to you and when combined with the excellent presentation depth and imaging result in an involving presentation. Bass is powerful and very capable, the midrange is forward and presented in a front-and-center way, and the treble has a great balance between bright and dark, but the integration of the entire spectrum is puts everything together in a cohesive and realistic way. While there is a slight analytical hint to notes, the overall sound is liquid and smooth and forgiving of tracks that aren’t all that well mastered.

The capability of the DC4 to recreate depth within the presentation and clarity are quite dependent on the source and track, and regardless of the track or source, the width is on the lower end of the competition. The attack of the DC4 is good, although not the fastest while decay is quite good with the ability to sustain a note if necessary. Transparency and coherence are excellent with resolution/detail that is in the upper echelon of the price range while dynamics are about average.

Overall, the warm, smooth, and forgiving DC4 gives an engaging presentation with excellent soundstage depth and imaging. For $500 the DC4 can handle just about any genre, but listening to music with good depth and a clean master will show off its stuff.

Source matching

Portable Sources, DAPs

Clip+ (rockbox): This is a pretty good match as the presentation of the Clip+ matches well with the DC4 due to the depth of the presentation and punchy sound to go with an overall good tonal combination. When you factor in the size and cost of the Clip+, the combo is a winner for on the go use, especially considering the price. However, compared with much costlier specialty DAPs and DAPs with amps the sound is a bit flat. 4/10

Apple iPhone 4S: This source is very close to the performance of the Clip+, but with a tiny bit more space and a little less in the dynamics department resulting in a slightly flatter sound. The bass is a bit less pronounced with the 4S than the Clip+, but only by a slight bit. 3.5/10

Apple iPad 2: A good deal less dynamic than the Clip+ making for a presentation that is on the boring side, and not quite up to the clarity of the Clip+ or iPhone 4S. 3/10

HiSoundaudio ROCOO Power: The ROCOO is about imaging and a sweet, natural sound, and it delivers on those fronts, however, but there are other characteristics missing, specifically the depth of the presentation and the bass impact. The ROCOO has better bass response with the DC4 than most CIEMs I have paired with it, but it is still lean in the deepest registers. Width of the soundstage is larger than that of the Clip+, and detail levels are higher, but without the depth, the presentations just don’t come to life in quite the same way. The ROCOO can perform well with the DC4, but more often than not, another source is a better match. 3/10

HiFiMan 801 (GAME card): With a more spacious presentation that displays the imaging qualities of the DC4 along with more resolution of the soundstage space, better dynamics, and more bass capability making for an enjoyable presentation that is superior to the above sources. However, the amount of difference isn’t huge and the 801 can make some tracks overly warm, sounding a bit thick, lowering clarity. 8/10

Realtek HD Audio integrated sound card: The DC4 doesn’t sound very dynamic or clear with the on-board sound card, resulting in a lackluster performance. Dynamics were poor and the speed of the presentation was a bit slower than usual. Soundstage space was about on par with the Clip+. 1/10

Portable Sources, DAPs with Amps

iPhone 4S ->

i.Fuzen: While the overall presentation is wider than the iPhone 4S HPO, the midrange is pulled more forward with the i.Fuzen. This leads to a different sound with vocals that sounds a bit off. However, the overall sound is cleaner and the bass is more impactful and has better control. 4.5/10

Headphonia Headstage Arrow 4G: The Arrow 4G matches well with the 4S both in size and sound, offering a smooth and enjoyable presentation that has good depth and an engaging presentation. Bass is solid and the spatial presentation is good. I really can’t fault the 4G with the 4S because the 4S is holding the 4G back. 6/10

Neco V2: This is not the synergist pairing the V2 is with the modded iPod due to a more mid-forward presentation of the iPhone 4S due to a too mid-forward presentation that hurts the overall depth of the presentation. This brings out the issues with tracks/iPhone DAC, and amp. If you like a very mid-forward presentation, this will give you what you want, but there are better, albeit more expensive options. 4.5/10

Just Audio uHA-120:The uHA-120 pairs well with the iPhone 4S, giving the best presentation of the amps tested with a combination of transparency and imaging to go with a great balance between width and forwardness. Bass is good, and everything else is 6.5/10

Headamp Pico Slim: This is a nice combo and the PS sits in a sweet spot with the iPhone 4S from a presentation standpoint. The presentation is on the brighter side for the amps and bass response is a bit less than the other amps tested. 5.5/10

Modded iPod ->

Arrow 12HE: The Arrow 12HE isn’t bad, but the treble region isn’t as focused or refined as the other amps. The 12HE has a laid back presentation that doesn’t have the best depth to the presentation. 5/10

Arrow 4G: The 4G improves quite a bit over the original 12HE with a much better treble presentation and better depth of the presentation, which is still laid back and a slight bit warm. Depth of the presentation is improved as is deep bass. 7/10

Pico Slim: The Pico Slim is very transparent and shared the Neco V2 presentation of less width and more depth to the presentation. The PS is a little more mid-forward and brighter with excellent imaging recreates a convincing performance. The PS shares a very engaging presentation with the Neco V2, although the overall sound isn’t quite as involving for me, but at a much higher price and much smaller size. 8/10

Meyer Audio Stepdance: With a wide and laid back presentation, the Stepdance handles the DC4 quite well with good bass impact and an overall involving presentation. Pushing the presentation back, the Stepdance loses the imaging and presentation depth of the Neck V2, however the depth of the presentation is still good. The Stepdance gives the DC4 a bit more of an analytical sound than many of the other amps. 7/10

uHA-120: Compared with the Neco V2, there is less depth to the presentation, but other than that the combo is quite good. The neutral presentation of the uHA-120 allows the DC4 to let its transparency and coherence shine as well as the sonic signature of the tracks. Bass is slightly less impactful than the V2. 7/10

Neco V2:There is great synergy with this combo with the Neco recreating amazing imaging and a note attack/decay that is very natural and realistic. The overall width of the presentation isn’t any wider than any other amp, and a bit less in the width compared with some others, but the V2 has a magic that makes me want to go back to it and just listen, not review. Bass is excellent with surprising texturing and depth. If you get the DC4 and want a portable amp, the V2 (or possibly new V3) is a great buy for the price. There is no noise but a slight volume imbalance at very low volume levels. If you get one, make sure you ask for a low gain and log volume pot. 9/10

Epiphany Audio EHP-02: While the O2 doesn’t do anything wrong, it just doesn’t have the magic of some of the other amps including the similarly prices Neco V2. The sound is colder and more clinical, which doesn’t match well with the DC4, at least for my taste while having options for the other amps. 6/10

ADL Cruise: The Cruise, as always, is more immediate than the other amps, which I find to be a great match for the DC4. The presentation is brightened up and speed is increased, but not losing much in the way of smoothness. While those attributes are very positive with the DC4, the imaging and depth of presentation isn’t what it is with the Neco V2, 627, and Pico Slim, even though the presentation is nice and wide. Plus, there is a hiss between tracks and with quite passages of tracks. 7/10

Portaphile 627: This combo is a good one as the 627 allows the DC4 to shine with great clarity, detail, and focus while not having any weaknesses. The presentation is a bit more laid back and slighty wider compared with the Neco V2, but the depth and imaging just a bit behind. Bass is more prominent, but just by a bit compared with the V2. Even with additional detail, the 627 is very smooth and enjoyable. 9/10

801 ->

Neco V2: Not quite the pairing this amp was with my modded iPod, the V2 still has a very impressive depth to the presentation. A bit brighter than the O2, the treble quality isn’t quite smooth as the O2 nor is the presentation width as wide, but the depth does give a little more dimensional presence to the V2. Bass is quite well controlled and has a texturing to it that is very nice. 8.5/10

EHP-O2: The O2 is an effortless amp in this configuration with great punch and impact, although not as much as the 627. In comparison with the much more expensive 627 the O2 lacks refinement, power, and space, but without that comparison the O2 is a competent competitor to the V2, allowing the DAC capability of the 801 to shine through. 8.5/10

627: Comparing the HPO of the 801 with GAME card vs. the 627 was a shocker as the 627 has much better focus, imaging, and clarity. After listening to the 627 for a while (and getting lost in the music) then switching to the HPO of the 801 I was surprised by the apparent lack of bass control and overall focus of the presentation. The 627 also opens up the presentation of the DC4 with an expansion in size all the way around. Also, the bass weight and capability increases when the DC4 is paired with the 627, as does the treble smoothness. Unfortunately, due to the sensitive nature of the DC4, the 627 exhibits electrical noise between tracks, reducing the score by .5. 9.5/10

Desktop Sources

HUD-MX1 (OPA1611): The MX1 sounds nice with the DC4 giving a very clear presentation that with good detail. The depth of the presentation space isn’t all that great, holding back the DC4. However, there is a severe channel imbalance that prevented me from listening at low volumes. Due to this, I decided to try an amp with the MX1. Without an amp, the score is 1/10 due to the severe volume issue.

-> Neco V2: I chose this amp due to the price point and found that the match wasn’t the greatest. The V2 isn’t as smooth with the MX1 as with other sources, but the clarity of the MX1 does carry over. Given the depth of the MX1 presentation isn’t all that great, this amp doesn’t help much in the presentation, although it still outperforms the entry level portable DAPs. 5.5/10

Cruise: The Cruise has a nice, bright, and clear presentation, however when compared with the D1, it sounds a bit smeared/blurred. Other than that, which isn’t surprising given the price difference, the Cruise is very dynamic, immediate, and punchy. I thought this was a good match from a sound signature standpoint as the strengths of the Cruise bring out the best of the DC4. But, there is a constant hiss between tracks and in quiet passages reducing the score by 1. 7.5/10

Anedio D1: The D1 is a good match due to the clarity and excellent imaging. Compared with the 801 -> 627 the presentation is brighter and clearer, but not quite as focused and transparent. Bass weight is about the same, although the soundstage size is slightly smaller. Both the 801 -> 627 and D1 have their strengths. 10/10

Source Summary: The DC4 is selective about the sources that it sounds best with, which are those that are of the mid-forward type with good depth to the presentation. While more expensive sources sound better than the entry level DAPs, more expensive sources didn’t necessarily sound better than mid-priced ones since presentation matching is very important. For example, the Clip+ was enjoyable and the relatively low cost Neco V2 amp outperformed all other amps, at least for presentation when paired with my modded iPod. In addition, the DC4 is very sensitive and can bring out the hiss/noise in your sources more so than just about any custom IEM I have heard. The DC4 is very dependent on the source and track for determining how warm and clear the presentation will be, so choose your source wisely!

Dunu DC4


DUNU’s first custom IEM, the DC4, is a winner in many ways providing an extremely involving and enjoyable presentation that is mid-forward, liquid, and rich. Transparency and coherence are top notch within the price range and close to CIEMs that cost double, and when paired with a synergistic source, the depth of the presentation is impressive. With a frequency response that is fairly balanced but not necessarily neutral, the DC4 is fun and quite capable in the bass response. Certain characteristics change depending on the tracks and sources, improving or reducing the listening experience, however the DC4 is quite forgiving of poorly mastered tracks.

Overall, the DC4 has a great sound signature with enhanced, capable and warm bass, a liquid midrange that is presented up-close and personal, and treble that has a nice balance between bright and dark, all leading to a very engrossing and non-fatiguing experience. The DC4 is a good starter custom IEM as it has a very enjoyable sound, it can grow with you as you upgrade your sources, and will be forgiving as you improve the quality of your music collection.


– Depth and imaging of the presentation are magnificent with the right source match

– Exceptional transparency and coherency for the price range

– Very good note decay, especially in the bass region


– Interior of the soundstage can become congested when playing busy tracks with lower end sources

– Ultra-sensitive design brings out the noise/hiss in players that don’t have ultra-low noise floors

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About Author

Having a life-long love of high-quality audio and gadgets, average_joe got back in touch with his audiophile side after a hiatus caused by life. His focus became headphones and related gear as the size and price fit his life better than home audio. He believes the entire audio chain is important, and likes to continue to think past the headphone and on into the head, as he believes understanding the details of how we hear will lead to a better audio experience.

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