Fit and Comfort

Seen above is the right channel of the DUNU VULKAN installed into an artificial ear mold, and I am using the included size M white bore silicone ear tips. This was my typical combination for personal use too, and illustrates the nature of the achievable fit with these IEMs. I do have average-sized ears, and the ear mold above represents my own experiences well enough as a proxy. The semi-custom design of the shells shaped for the ear concha with ergonomics in mind works out fairly well for most ear types, and despite the shells being on the larger side, the clever integration of the nozzle means the part inside the concha is not that large. The thing to note is the nozzle itself is larger than average at 6.2 mm in diameter, so those with smaller ear canals might not like the fit. Multiple contact surfaces in the inner ear support the IEMs, which helps as these weigh ~8.5 g each without the cable. The extensions on the shells combined with the angular housings on the cable make for a relatively long pairing, which is good since the shells are further away from the cable. I ended up with a very good fit and seal thus, and the ear hooks adding further support made this a comfortable experience. The vents help with some pressure equalization for long listening sessions, but not at the expense of hurting passive isolation on this fairly closed set.

Audio Performance

Audio Hardware

There is a lot going on inside the DUNU VULKAN, which is why I am not only showing the usual wireframe composition of all the parts, but also a GIF that goes through how these come together. Suddenly, the thicker shells make a lot of sense given how DUNU has made this an absolute unit. Similar to DUNU's previous models, the DN-2002 and DM-480 (Side note: DUNU, please keep a history section of your products on the website), two dynamic drivers are employed. There is an 8 mm nanocrystalline titanium-coated diaphragm dynamic driver with a coaxially placed 8 mm dynamic driver using a crossllinked structural foam cell dome diaphragm suspended on a polyurethane-based independent surround, and the foam allows the DD underneath to still push sound waves through. This can be incredibly hard to engineer without the two drivers becoming an outright mess, yet DUNU decided to add to the complexity by reserving these for the low and lower mid-frequencies only.

For the first time in DUNU's history, we see a 3D-printed acoustic waveguide to direct the hybrid driver configuration. Two Knowles balanced armature drivers handle the mids and highs followed by a dual Knowles supertweeter BA driver for the ultrahigh frequencies. The waveguide combines with an electronic crossover system to put this 2+1+1+2 hybrid setup (2 DD, 4 BA) together in the VULKAN. It's still a pretty efficient system when it comes to power requirements as the VULKAN has an average rated impedance of 15 Ω, which may not be true throughout the entire marketed 5–40 kHz frequency range owing to the different drivers and likely non-linear impedance response. The sensitivity is slightly above average at 109 dB/mW, so purely by numbers, it is easily handled by even a basic USB Type-C dongle. The DUNU VULKAN is just fine with mobile devices thus, and going with one of the portable Bluetooth options we have covered before also makes this a wireless solution. The lack of a 3.5 mm audio jack for most phones these days is another reason to consider a DAC/amp for portable use. If not on the go, space is less of an issue, but the relatively short cable might still be a handicap if connecting to a PC as the audio source.

Frequency Measurement and Listening

I will mention that I have a general preference for a warm-neutral signature emphasizing a slightly elevated bass and smooth treble range with detailed mids and good tonal separation. I also generally prefer instrumental music over vocals, with favored genres including jazz and classical music.


Our reproducible testing methodology begins with a calibrated IEC711 audio coupler/artificial ear IEMs can feed into enough for decent isolation. The audio coupler feeds into a USB sound card, which in turn goes to a laptop that has ARTA and REW running and the earphones connected to the laptop through the sound card. I begin with an impulse measurement to test for signal fidelity, calibrate the sound card and channel output, account for floor noise, and finally test the frequency response of each channel separately. Octave smoothing is at the 1/12th setting, which nets a good balance of detail and noise not being identified as useful data. Also, the default tuning was used for testing, and no app-based settings were chosen unless specifically mentioned. Each sample of interest is tested thrice with separate mounts to account for any fit issues, and an average is taken of the three individual measurements for statistical accuracy. For IEMs, I am also using the appropriate ear mold fitted to the audio coupler for a separate test to compare how the IEMs fare when installed in a pinna geometry and not just the audio coupler. The raw data is then exported from REW and plotted in OriginPro for easier comparison.


The IEC711 is such that you can't really compare these results with most other test setups, especially those using a head and torso simulator (HATS). The raw dB numbers are also quite contingent on the set volume, gain levels, and sensitivity of the system. What is more useful information is how the left and right channels work across the rated frequency response in the DUNU VULKAN, or at least the useful part. The left channel was separately tested from the right one, and colored differently for contrast. I did my best to ensure an identical fit for both inside the IEC711 orifice, so note how the two channels are basically identical throughout the entire frequency range. It's well past the coupler resonance that any discrepancies show up, and those have to be taken with a grain of salt anyway. In practice, these are very likely driver matched units, which is expected for IEMs in this price range. Measurements taken after 30 hours of testing, including with these playing a mix of various songs as well as white or pink noise and sine sweeps showed no differences. There was no perceived burn-in effect thus, and none was measurable either. The response with the anthropomorphic pinna in place matches the ideal scenario in the coupler very well, which is also an indicator of how good the fit and seal was in the artificial ear.


Here is the average frequency response for both channels of the DUNU VULKAN plotted against my personal target taken from VSG.squig.link, which also gives you an idea of my personal preferences to better correlate any possible biases. The tuning of a set of headphones or earphones does not have to match my target as long as it is tuned with some direction, makes sense, and is executed well. After all, no one set will appeal to everyone, and having different options is what makes this hobby so interesting and hard to quantify. DUNU says, and I quote, "VULKAN is designed to possess a classic 'U-shaped' sound signature that brings out deep bass and sparkling highs. Colored with precision, the resultant sound signature is a crowd pleaser, imaged for a larger-than-life presentation, a lush, full midrange and a high end with just the right amount of sparkle."

I can agree with a lot of that, yet found myself having issues with certain parts. To begin with, the VULKAN is certainly tuned with a U-shaped signature that becomes more neutral with a bass boost than anything else. There's nearly 8 dB of elevation in the bass from the lowest point in the mids at 500–00 Hz; however, most of this SPL boost occurs from 200 Hz and below to focus on the sub-bass more than the mid-bass. My expectation of a deep, impactful bass from the two DD drivers was validated, with definite thump in the sub-bass, but not much room is left for those wanting more. In fact, DUNU seems to have pushed these drivers as far as possible since a 2–3 dB bass shelf applied via EQ caused noticeable distortion. There's also a loss of clarity on the trailing edges of tones in the bass region proper, so much so that the mid-bass is actually a weak point for the VULKAN in my books. I didn't get a true rendition of kick drums and bass guitars strings, with there being fake warmth without any substance behind it.

On the flip side, the VULKAN more than makes up for the middling bass response with one of the best mid-frequency reproductions I have heard on IEMs. It's relaxed and soothing throughout, with great vocals that are just forward-facing enough to take the center stage when needed. Technical performance in the mids is excellent too, with a great sense of space for all the tones to breath freely courtesy a deep and wide soundstage. Tone imaging is on point too, especially in the center of your head and around the ears, which helps getting lost in the music. The transitions from the bass to the mids and highs are also appreciably smooth, and perhaps this is where the acoustic waveguide and electronic crossover system has to be applauded. Instrument separation is also well done, and we then see the typical applied pinna gain.

Depending on your particular HRTF and/or vocal preferences, it might be a touch honky, or even underwhelming for some. The pinna gain is quite broadly placed but not very aggressively—it won't win over everyone, but is more likely to satisfy everyone. I found myself nitpicking things though, as you might, too. The rollercoaster continued with a generally impressive treble response with no sibilance or fatigue and a clever use of the Knowles BA drivers to achieve good presence for piano key resonances and string instruments. Cymbals clashing also had hang time throughout, and I can certainly see a use case for classical and orchestral music here. It is colored in this region though, coming off somewhat extravagant with certain instrument classes that benefit jazz and R&B. The sparkle continues to a point before things crash in volume, and there is a sense of added air from 12 to 15 kHz before a significant roll off. I thought this helped with overcoming what many call BA timbre, although the colored tuning doesn't make for an extremely realistic sound in the higher frequencies either way. Overall, I'd classify the VULKAN more for mid-heads than anyone else, although jazz and acoustic guitar lovers will have a jolly time, too.


The price range of the DUNU VULKAN is not the most crowded since companies are either going lower or way higher these days. One set that is almost always in the discussion here is the MOONDROP Blessing2, or the slightly re-tuned Blessing2:Dusk. Unfortunately, I have not heard either to talk about how the VULKAN fares against them. Instead, I chose three other hybrid sets in the price range of the VULKAN I have here, including the very interesting Audio Hekili made by a single audio engineer in China and going with a well-tuned 1 DD + 7 BA driver configuration. I'll see if I have the time to cover it in more detail since it has been overlooked by most reviewers, but the Hekili is a great example of getting bass reproduction right, with a nice, deep sound and details maintained throughout the mid-bass. Where it does bow down to the VULKAN aside from the accessories and finish is in the lacking mids and fatiguing lower treble. It does cost less than the VULKAN though, so perhaps it is of interest depending on preferences.

What should not be in the discussion is the poorly tuned, weakly performing HarmonicDyne P.D.1 with its 1 DD and 1 planar driver configuration. It is hardly noteworthy outside of accessories and finish, effectively making it the Yang to the Hekili's Yin. The VULKAN wins easily here. Other IEMs priced similarly or higher are also bested by the VULKAN, including the FiiO FA7s and most Campfire Audio products. But the biggest challenge so far might come from the XENNS Mangird Tea 2 (review coming), which is an update and upgrade to the original Mangird Tea that was impressive in its own right. This 1 DD + 6 BA set is quite analytical and bests the VULKAN in detail retrieval most of the way, although I wouldn't recommend the Tea 2 for bassheads unless you absolutely value a cleaner bass with improved clarity over impact and loudness. The VULKAN makes up for it by offering a higher dynamic range for instruments and vocals, and handles transients better. It also makes the Tea 2 sound hollower in the upper mids by comparison, but the Tea 2 wins overall in the treble if you prefer a neutral tuning that also extends further. This comparison is effectively a wash for me in terms of tuning and technical performance, and the better accessories of the VULKAN and knowing the tuning of the Tea 2 is easier to find elsewhere compared to the VULKAN's tips the scale in favor of the DUNU offering.