Nuance and Finesse – Dunu DK-4001 IEMs & Hulk Cable Review
Dunu DK-4001 is the current flagship from the Chinese company Dunu, and it is a total innovation from their previous model, the DK-3001, as it has a much better ergonomic, cool aesthetic, and a good amount of tips and accessories. Dunu Hulk also makes an intro in this review, as Audiophile-Heaven expands with more cable reviews. DK-4001 is priced at 900 USD, so the main competitors for DK-4001 are HIFIMAN RE2000 Silver, Lime Ears Model X, and Campfire Atlas.
Dunu is one of those companies from China that didn’t want to set out to make just cheap products, but didn’t want to make them as expensive as possible, so instead they dedicated and set out to create some of the best build quality, best overall package, and just overall great sound and products. It is interesting to note that they do provide good aftermarket service, and that they do not disappoint in any aspect with their products, and to date, are one of the most reliable Chinese IEM companies.
It should be noted that I have absolutely no affiliation with Dunu, I am not receiving any incentive for this review or to sweeten things out. I’d like to thank Dunu for providing the sample for this review. This review reflects my personal experience with Dunu DK-4001 & Dunu Hulk. Every opinion expressed is mine and I stand by it, the purpose of this review is to help those interested in Dunu DK-4001 & Dunu Hulk find their next music companion.
You can alwas get DK-3001 PRO and The Hulk Cable from www.amazon.com here: https://www.amazon.com/DUNU-TOPSOUND-DUNU-DK-4001-Resolution-Flagship/dp/B07LGG3PQH/
First things first, let’s get the packaging out of the way:
I have some talk to do here, because for the first time in a while, we get a nice looking package that has enough extras to give us something to play with. Starting with DK-4001, there is a plethora of tips included, and the best part is that some of those are actually spinfit tips, but those are a special selection made just for DK-4001.
Furthermore, you may notice some odd-looking jacks inside the package, and unless you read another review, those won’t make much sense, but the short version is that both DK-4001 comes with a fully modular cable, and Dunu Hulk itself is a fully modular cable. This means that you don’t have to keep changing the cables every time you want to go from a single ended source to a balanced one, or between different sizes of balanced cables, like going from a 2.5mm to a 4.4mm output.
This makes comparing different sources much easier, and also makes the entire process of owning high end IEMs and headphones more fun in the long run. There is also a carrying case included with DK-4001, and that’s just the little accessory on top of the entire already great package.
Dunu Hulk also comes with those modular jacks, so you don’t have to worry, the first cable made and sold standalone by Dunu has all the perks of other Dunu products.
Starting with the build quality of DK-4001, you will quickly notice that there is a huge difference between it, and the DK-3001 IEM which I reviewed in the past. The difference is not in the build quality itself, actually, as both are really well built IEMs with high-quality cables and with good comfort, but there is a large difference in how each of them fits in your ears, with DK-4001 being considerably more comfortable than DK-3001, due to longer bores, and to a much more ergonomic design.
The MMCX connectors are also much better, since the cables can be removed and the cables will not turn freely inside the socket, compared to the original DK-3001 where multiple reconnections of the cable did loosen the connector and lead to a less reliable IEM in the long run.
The aesthetics of the DK-3001 are pretty spartan and basic, with a slightly industrial, yet modern looking IEM greeting you. It is accompanied by a thin and flexible cable, and DK-3001 has a larger vent on the outer plate, along with a smaller vent hole on the inside. Since DK-4001 has 4 BA drivers and one Dynamic driver, it needs good ventilation so that you won’t feel any driver flex, and Dunu manages to deliver quite well on that, and you feel no flex with DK-4001.
Furthermore, with DK-4001 you also get no cable noise, or microphonic noise, and you get a really comfy IEM, thanks to its very ergonomic and well rounded design with no hard edges and thanks to a bore tube that is long enough to reach a comfortable fit with your ear.
The other thing you should be glad you have with DK-4001 is the large selection of tips, which include spinfit tips, along with foam tips from comply and with a few unbranded silicone tips, so that you can eventually get the best fit you could dream about with it. The selection of tips changes the sound, as with every IEM, and I found the best sonic / comfort balance with spinfit.
DK-4001 offers mediocre isolation from the outside noise, since it has quite a few ventilation ports, but it offers one of the best comforts I have had with a IEM, making me desire to wear it more and to use it more.
Now, the cable. Dunu Hulk, is another story entirely, because it is not the same cable as the cable that DK-4001 comes with. Dunu Hulk is a much thicker and less flexible cable, and if you ever wanted to have a cable that feels thick and high-quality, Hulk surely won’t break regardless how much you beat it around and use it. Not just that, but Dunu Hulk tends to be one of the most resilient modular cables on the market at this moment, relying on the same mechanism as DK-4001, so you know their best tech went inside both the IEMs and the standalone cable.
Overall, we have an ergonomic, comfortable and reliable IEM, and a thick, slightly rigid, but very resilient cable with DK-4001 and Dunu Hulk.
The sonic performance of DK-4001 is what I would call a mixed coup. The fact is, the sound itself is really really good, but it mixes things to such a degree that it is a bit hard to put in words, compared to a more traditional IEM like DK-3001 or Falcon-C, both of which had a pretty usual V-shaped and neutral signatures. With DK-4001, you get a high emphasis on the bass, and especially the sub-bass, a strong female performance, along with a solid male performance, but with a smooth and relaxed top end that’s smoother than you’d expect from a IEM made by Dunu, especially if you heard or will hear any of the other IEMs designed by them. Uncharacteristic of them, DK-4001 is actually soft and musical overall, despite the bumps and dips in the frequency response graph. It surely is not a very exciting presentation and won’t get you up all night, instead softly tickling you with a forgiving presentation that you will want to lean on for hours in a row.
The bass delivers an impact that I’ve yet to see on many IEMs, with no roll-off even at 20Hz, so you get the extension you always dreamt of. There is a good articulation and excellent speed, and although DK-4001 is far from being a basshead IEM, the bass could be considered its strong point. There is good weight to each musical note, and there’s also a pretty linear overall extension up until 600 Hz, after which there is a bit of a dip that goes down a gentle slope.
This being said, Dunu didn’t go for the typical dip in the midrange that would have made DK-4001 a pretty typical V-Shaped IEM, and instead the voices are pushed pretty forward, and the textures are what I’d call soft to very soft, with nothing being aggressive, and sacrificing some clarity and punctuation in every sound, for a better understanding and expression of nuance. The midrange is tied pretty nicely to the bass, since the 13mm driver Beryllium driver takes care of both the bass and the midrange, making DK-4001 pretty coherent in terms of overall decay and speed. The soundstage is not large, nor wide, but it has good depth, providing a very well-rounded performance, and a pretty nice kick for those who wanted to feel as if they were in the same room as the singer, but who still wanted to have a good sense of depth and distance between the instruments.
The treble is rising up until 7kHz, after which it starts rolling off and out. The fun part here is that the entire IEM doesn’t get to sound dark or thick because of this, but DK-4001 stays within what I’d call neutral, yet soft and musical, truly a tuning I haven’t heard any other IEM going for to this date. If you’ve worked in music mastering before, I would call DK-4001’s sound wet and non-fatiguing rather than dry or edgy, as the treble avoids any harshness or aggression in music, without getting heavy, thick or bassy.
Dunu Hulk, as a cable, is pretty much at the other end of the spectrum, and it tends to sound smoother, warmer and more creamy than most stock cables, and especially when you pair it with bright and thin sounding IEMs, you get a heavenly match.
Given the pretty low impedance of 32 OHMs and the 112 dB SPL, DK-4001 is easy to drive and will pair well with any source, although it does tend to suck more juice from your source than most IEM hybrids. This means that you end up turning the volume higher, which could lead to some hiss if you had a hissy DAP like Hiby R6, but you’ll hear almost to truly no hissing with more tame DAPs like DX220 and FiiO M11.
DK-4001 is best complimented by a DAP that sounds more articulate, and is not very well complimented by softer DAPs like QLS QA361, since DK-4001 is already pretty soft. This being said, the soft cable, good ergonomics and fair noise isolation will make you want to take DK-4001 quite often with you, and just plug into your phone, and hope for the best. In this situation, I always recommend using Roon if you can, because you get a selection of DSPs that could help match IEMs like DK-4001 with a sub-par source like a smartphone better.
Dunu Hulk, on the other hand, is what I would call technically portable. It is portable, it has very solid connectors, very solid build quality, it has no microphonic noise and also makes for a beautiful cable, but at the same time it is rigid for an IEM cable, and I would probably have considered it a 10/10 headphone cable, rather than a headphone cable. Furthermore, with Hulk you get a rather heavy cable for IEMs, which isn’t entirely practical, but, at least it makes for an excellent cable upgrade for 300 USD if you wanted something that does look more reliable. If you ever had a Sennheiser IE800, you may be acquainted with the cable hardening issue, and you will also be happy to know that Dunu Hulk does not suffer from such issues and it is a pretty much perfect cable.
The other little magic part with both DK-4001 and Hulk is in their modularity, as both can be connected to a selection of sources, both single ended, and balanced, even the newer 4.4mm balanced port, as well as the 3.5mm Balanced 4-pole connector that HIFIMAN DAPs, as well as a few others use.
As promised, the comparison list is fierce, with HIFIMAN RE2000 Silver, Lime Ears Model X, and Campfire Atlas being very pertinent competitors for an IEM that costs 900 USD. Each one of those is pretty similar in terms of price, or at least close enough to make the comparison interesting.
Dunu DK-4001 vs HIFIMAN RE2000 Silver – The package is better for DK-4001, and so is the default cable, which is modular for DK-4001 and normal for RE2000 Silver. The comfort is good for both, and both offer similar passive noise isolation. Both are similarly easy to drive and both are similar in revealing how hissy a source is. I have been using RE2000 Silver with Spinfit tips, which need to be purchased separately, while for DK-4001, you get them inside the package. When it comes to the sound, though, it is quite different, with RE2000 Silver being very textured, analytical, detailed, and much more aggressive and engaging, while having a similarly sized soundstage as DK-4001, but DK-4001 having a much softer, more easy sound, despite having a similar tuning and similar overall macro detail level. Both are quite interesting, but if you’re into a lot of rock and metal, the textures of RE2000 Silver may compliment your music more, while if you’re into Jazz or easy music, DK-4001 should compliment it more.
Dunu DK-4001 vs Lime Ears Model X – Lime Ears Model X is that one IEM that has two sounds, as it has a physical switch that changes its signature from a colder more analytical one, to a warmer, larger and more enthusiastic one. This means that regardless of the position that switch is in, you get two signatures that are different from the soft and neutral-ish signature of DK-4001. In terms of comfort, DK-4001 is much more comfortable than Model X, which is larger, has a cable with hard memory wire around the ear, and which just doesn’t sit quite as comfy compared to the ergonomic DK-4001. The body of DK-4001 is also considerably smaller. This being said, Model X does not have any driver flex either, and they do offer better passive noise isolation. The default cable is way better on DK-4001 and I would recommend upgrading the cable of Model X if you decide to go for it, with something like Dunu Hulk, as they pair really well together.
Dunu DK-4001 vs Campfire Atlas – Campfire Atlas is one of the more pricey competitors for DK-4001, and after hearing it, you immediately know why, as it provides a very large and grandiose presentation, although if you like its sound, you probably aren’t looking for the character of DK-4001 to being with. In terms of packaging, the carrying case of Atlas is better, and the cable is softer and more flexible, but the cable of DK-4001 makes a much better overall cable if you have multiple sources, especially if you have both single ended sources and balanced sources. If you like comfort, DK-4001 is more comfy, has no driver flex, while Atlas does have driver flex. DK-4001 also sits more comfortably in the ears and feels more secure while walking and doing activities. On the other hand, in terms of sound, you really will go for one or the other, Atlas is very much a V-Shaped IEM with a strong taste for bass, sounding huge and having a huge stage, while DK-4001 is much more of a close friend, intimate IEM that’s made to sound soft and musical, non-aggressive and easy on the ear, all while keeping a good degree of neutrality.
In terms of pairings, I have chosen iBasso DX220 featuring AMP 9, Mytek Brooklyn DAC+, and FiiO M9, all of those being pretty interesting DAPs to pair with your DK-4001
Dunu DK-4001 + iBasso DX220 (AMP 9) – When you pair DK-4001 with a pretty detailed and lively source as DX229, you get a very nice final result, because the mellow and soft character of DK-4001 is complimented by DX229, you get a more vivid midrange presentation, a larger overall soundstage than the average, and you also get a very good amount of detail. This being said, you also get access to Tidal, Streaming services, as many as you could desire, and the ability to connect more headphones and IEMs to DX220, as it has enough driving power even for most full sized headphones. There is no trace of hissing, and overall, this is one of my top choices if you can afford it, especially for a portable.
Dunu DK-4001 + Mytek Brooklyn DAC+ – There is a good reason to include a high-end desktop DAC/AMP in this pairing, because many want to know if DK-4001 will make sense when you get home and forget the noise of outside as well, and well, it still is a very relevant IEM. Mytek Brooklyn DAC+ tends to be a very wide and well-rounded DAC/AMP, with a huge holographic soundstage, and DK-4001 surely is complimented nicely by it, getting a much wider and more relaxed, expanded sound. There is better layering than with most sources, and the detail is also really good. This being said, the mellow and soft character of DK-4001 is not lost, and it doesn’t get aggressive, and if anything, the pairing is quite musical, yet a touch more exciting and engaging than when pairing DK-4001 with the average source.
Dunu DK-4001 + FiiO M9 – With FiiO M9, you get a very good portable DAP, that’s based on FiiO’s engineering design, with enough power to drive most portables, but also a sound to match its price. M9 is pretty pocket-friendly, and you get a very soft and docile presentation with DK-4001, and if you wanted to experience the more intimate, gentle, soft, yet very neutral sound of DK-4001, then M9 is one of the best DAPs to pair it with.
Value and Conclusion
The value of Dunu DK-4001 is a bit questionable, as it is a flagship, high-end IEM, and it isn’t exactly a cheap option, instead actually being a pretty pricey IEM. This doesn’t mean it isn’t good, it just means that you should chose it if you’re going for its precise signature, as it has a very specific tuning, and it is not quite a whole-purpose IEM like other flagships are. It does have some aces up its sleeve, like the amazingly handy modular cable, Spinfit cables included in the package, and the nifty carrying case and premium package it comes with, making it a very good option.
Dunu Hulk is also pretty fair in terms of pricing, especially for a high-grade cable, but it is a bit more than most expect or imagine paying for a cable at this moment, especially if you’re new to purchasing aftermarket cables. On the other hand, if you’re a seasoned IEM user and have had your share of experiences with cables, you will know that for a fully modular cable, Hulk is just right in terms of pricing, especially if you have a brighter or harder to tame IEM that you always wanted to sound warmer, more rounded, and more creamy.
The package of DK-4001 is very all-inclusive and so is the build quality, which this time has both excellent build and excellent ergonomics, making DK-4001 one of the best IEMs I have served to date in terms of comfort, coming close even to the mighty HIFIMAN RE800 Silver, which barely makes any contact with your ear, so it is inherently comfy. DK-4001 is so well designed, it gets even better than that. No microphonic noise, and no driver flex also lead to a good comfort with DK-4001.
If you’re looking for a softer, more mellow sound that has a quick and well-bodied bass, but which doesn’t feel aggressive in any way, and will give you an intimate moment with your favorite singer, you will probably fall in love with DK-4001.
Also, if you’re looking for a solution to make your IEMs sound more creamy, a touch warmer, more rounded, and more musical, Dunu Hulk has a sound that will surely improve your listening sessions.
At the end of this review, if you’re looking for a high-end IEM, with good build quality, comfort, ergonomics, a soft, mellow, yet quick sound, with a slightly intimate stage, and which comes with both a modular cable and spinfit cables, you should totally consider DK-4001 as your next IEM purchase.
You can alwas get DK-3001 PRO and The Hulk Cable from www.amazon.com here: https://www.amazon.com/DUNU-TOPSOUND-DUNU-DK-4001-Resolution-Flagship/dp/B07LGG3PQH/
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Full Playlist used for this review
We listened to more songs than those named in this playlist, but those are excellent for identifying a sonic signature. PRaT, Texturization, Detail, Resolution, Dynamics, Impact, and overall tonality are all revealed by those songs. We recommend trying most of the songs from this playlist, especially if you’re searching for new music!
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Hope you’ll have the chance to review more Dunu IEMs in the near future too, I always wanted to grab an upgrade from my DK-4001 but there’s no other reviewer I currently follow or trust.
Super nicely written!
Amazing review, thank you for all your efforts!
Way cool! Some very valid points! I appreciate you writing this write-up and also the rest of the website is
Your website does not show up correctly on my apple iphone – you might want to try and fix that
What is not showing correctly? What version of iPhone do you have, and what browser are you using?
It is unusual for me to find something on the net thats as entertaining and fascinating as what youve got here. Your page is lovely, your graphics are great, and whats more, you use reference that are relevant to what you are talking about. You are certainly one in a million, man!
Thank you, happy to help!!
Just got the DK-4001 thanks to your review, thanks a lot for the write-up.
Happy to have been of help!! <3