THE PLUS:
-2 tuning choice
-good resolution and transparency
-excellent imaging
-fast treble attack speed
-safely tuned
-smooth cohesion (even more so Focus mode)
-realist and textured timbre to warm natural timbre (dependng of mode)
THE MINUS:
-poor bass separation and control
-lack of punch and definition of mid bass
-lean thin mids (Harmony mode)
-small intimate soundstage (even with wide bore that open the sound)
-lack of treble sparkle-decay-brilliance
-light note weight (Harmony mode)
-safely tuned
-not fun nor engaging
-driver flex
-big housing
-cheapest cable ever for a 2.5K$ IEM
-sensitive to impedance output and gain of the source

TONALITY: 8.2/10
TECHNICALITIES: 8.8/10
CONSTRUCTION: 8/10
SOUND VALUE: Cannot apply (sound benefit=very low)
INTRO
Aroma Audio is an high end earphones company based in China. They create high end IEM since 2015 and have a solid fan base here on Headfi. They seem to specialize in hybrid and tribrid IEM. I didn’t find much info about their story so I can’t share anything more.
Today I will review their Thunder high-end IEM, which is an hybrid with 1 dynamic driver and 10 balanced armature.
Having tested about 20 pairs of earphones priced between 1000 and 4000$, let see in this review if the Thunder worth the big investment or is just a niche product for those audio enthusiast with too much money to spent.
CONSTRUCTION

Since these are loaner unit from a gentle canadian friend, I don’t have all packaging and accessories so I will only comment on the IEM and cable.
The IEM construction is OK, nothing mind blowing, it use medical grade resin plastic and have a rather uninspired design.The housing is big and chunky with very thick nozzle, so, for people with small ear hole it might be too much. They are light and have a recessed tuning switch that need a tool or nail to be able to use.
I do encounter driver flex issue, but it’s perhaps due to my ears.
At this price, the construction is underwhelming.

But the cheap cable is even more underwhelming and quite an insult for serious consumers. As seen in the pic above, its similar quality level as the BQEYZ KC2 cable, which is a 35$ IEM. So, this cable cost less than 5$. This is unnaceptable for a 2500$ IEM and sure have a marketing strategy of making you invest in a cable upgrade. I find this approach quite cynical. The owner of these IEM underline me how bad and disapointing is the cable, and let say i feel very empathic for him so come on Aroma, you can do better! PM me, i can suggest you lot of great cable company with 10-30$ cables that will feel like TOTL compared to this joke.
SOUND IMPRESSIONS

The Aroma Thunder is all about smooth near neutral immersive balance, it wanna cuddle you in it’s fully resolved tonality and intimate surrounding. It’s not here to impress you with vivid treble or big bass boom, it’s not an IEM using easy wow effect tricks to entertain the listener and tend instead to favor the fullness of presence over other part of frequency. Well, in fact, since it have 2 tuning choice, you do have the choice between a warmer bassier balance (Focus mode) or crisper more neutral and transparent musicality (Harmony mode).
The tonal balance can go from warm and thick L shape tonality to smooth, clean and airy (near neutral) U shape depending of tuning switch choice. You can decide if you want bass warmth to embrace tonality and boost lower mid range or go for a more lean and gently analytical tonality.
One thing that merit applause, its how cohesive the 10 balanced armature are tuned in a liquid organic way without any spike or harshness. The dynamic driver doesn’t feel detached but to my ears do have a slightly warmer and denser timbre that can be perceive, in Focus mode the DD inflict warmth that thicken mids and tend to make overall listen more laid back.
In this review i will mostly describe the Harmony mode, because it’s easy to imagine Focus mode: just add warmth that thicken timbre but affect transparency and resolution. Focus mode tend to affect negatively the technical precision and accuracy, but can be perceive as offering a more natural timbre, which is mostly positive for vocal that gain in lower mids harmonic.
So, in Harmony mode, the Thunder is far from being a fun or basshead tuning, it’s not a treble head tuning either, but what we can call mature neutral that doesn’t go analytical or cold sounding and have just enough bass boost to offer proper dynamic and note weight.
The bass is more about (colored) quality than quantity here, and it’s safely tuned to avoid any fatigue induce by too loud punch. Tone and weight is favor above texture and proper definition and separation. We have more su bass boost with just enough mid bass boost to offer proper slam. I might not be for basshead, but the punch is there and well felt, with a warm transition to mid range, not a clean separation. The extension is deep with vibrant and thick rumble, not a lean and clean extension so for contrabass it will lack texture and extension stability making the string feel a bit mor hit than plucked. The bass is thick and well layered, it’s not very resonant in impact, so toms instrument will lack a bit of fidelity in their acoustic propagation. It’s not the fastest bass not the tightest. It’s well rounded and offer juicy grunt that permit electric bass line to be well extracted (more so than acoustic). When you go Focus mode, the slam is warmer, thicker and a bit more impactfull, and the rumble have more headroom which stole spatial deepnest of Harmony mode.
I find the bass performance average for the price, and would say the same if the Thunder was selling for 1500$ less. It’s too safe in proper punch definition and energy to be truely engaging and the dynamic feel tamed too, kick drum isn’t very easy to perceive in presence and separation between bass and kick is dark, both instrument feeling at same amplitude level.
The mid range is the highlight of the Thunder, and more you listen to it, more you are rewarded with it’s understated and cohesive richness. In Harmony mode it’s transparent with realist timbre free of harsh grain or overly boosted texture. Thunder doesn’t struggle to present each instrument in its full singularity, each of team being carved in 3D rendering with smoothed definition edge that can make the mids feel darker than they truely are in fact. That’s the marvel here, it’s smooth yet highly detailed mid.While a bit thin with Harmony mode,the Focus mode go notably warmer and thicker, but to the cost of resolution and transparency. So, you have both choice between lush or lean mid range.
Harmony mode offer excellent imaging capacity, it feel open and deep in spatiality and near analytical in presentation. The attack is fast and thighs, more so than bass DD driver. Unlike lower end hybrid or multi-BA, the piano note attack have natural and clean resonance, it’s refined and don’t feel noisy in sustain-release.
These are the kind of mids that favor male vocal over female vocal. Male vocal are fuller bodied while female vocal are more about presence and have thinner body. We can say the same for bassoon against saxophone or piano against clavichord.
Now, the treble is quite detailed and snappy, but not very agressive nor very sparkly or airy. It does have minimum of openess to it as well as enough brilliance edge to permit acoustic guitar attack being well define, but whatever how much balanced you add, you will never get the sparkle with natural decay of a dynamic driver or EST. But this can mean half cooked treble too, which isn’t the case at all for the Thunder wich is full and gently crunchy enough with rich treble texture that will extract every details of percussions in a very elegant and delicate way. With the Thunder, you will not miss any percussions info, which are presented in fast and accurate way, very clean and well timed, if the kick drum was as well resolve, i would suggest those to drummer for pristine monitoring of their playing.
Nonetheless, these are near master of jazz trio, for blues too it might offer tremendous immersive and accurate experience, while for classical it’s hit or miss, due to thin violin presentation that have fast and abrasive attack but not the most pleasant timbre. Electric guitar too sound a bit thin and tamed in dynamic, but the presence is textured and detailed enough.
Spatiality is rather intimate, in the sens its average wide and tall but have rich deepness to it. This is due to center stage being a bit more recessed too, which explain some part of mid range being thinner than other. But we can dig in transparent sound layer in all freedom, which is a sign of high fidelity rendering.
Imaging is excellent, very accurate and precise even if not the most spacious in instrument separation when it come to bass and mids. Treble have more space, for ex, percussions doesn’t feel compressed at all and add slight sens of stereo openess.
SIDE NOTE:
The Aroma Thunder don’t benefit big amping but clean stable audio source with low impedance. They sound better at low gain with both the Hiby RS6 and Moondrop Dawn 4.4 which was mostly used for this review. RS6 pairing tend to make mids a bit more upfront, bodied and natural sounding, while Dawn 4.4 add a bit of spatial openess and deepness.
I struggle alot to find proper ear tips with those, and finaly go for short wide bore ear tips that open up headroom a bit and improve imaging and layering of bass, mids and treble. With those tips, i encounter driver flex which is certainly worrysome for an IEM of this price, but this might be due to my ears.
The stock cable is very underwhelming and justify fast upgrade, i get cleaner more dynamic and open sound with Tri Grace S cable.
The tuning switch is a little annoying since it’s recessed and you need a tool or nail to push it, so, it’s not very practical if on the go you want some vocal euphony while your on Harmony mode.
Construction and design is a bit underwhelming for this price bracket, in fact, back design motif are very same as Kiwi Ear Cadenza, plastic quality too, medical grade. The fact 2pin connector are flush on a curved body make cable connection not very well secure, so be cautious to not wear those under the rain since on water drop under 2pin connector can equal in dramatic damage.
Now, this is the part where i want to get philosopher about sound benefit we get with this very IEM. We can begin by saying those IEM are aimed for rich people and not true audiophile from middle or lower class. I would not say this for the Final A8000, GSaudio SE12, nor the UM Mext, and to a less extend, not even for the pricer Fir Audio Xenon 6.
Why? Because we get (long term) WoW effect with all of those, but no truely exciting one with the Thunder unless you haven’t listen to alot of IEM in different price range like I do, which is very possible.
Sure, treble speed, details and snap did impress, but it doesn’t stand apart in term of quality, spatiality and especially extension. These IEM doesn’t age well due to fast tech evolution and especially electro static drivers that are implemented in tribrid to permit proper sparkle, air and brilliance BA just can’t achieve.
So, the benefit return here is near 0. Because the Thunder are a ”Jack of all trades, Master of none” earphones at a price range that should promise something different, engaging and highly impressive in musical experience. Simply put, if i was rich I would be a kilobucks high end IEM collector and these will most likely take dust, while Sony Z1R and even bass light Shure KSE1500 (i’m not that afound off) will not take dust.
Thats my personal opinion based on real money value. IEM priced above 1000$ should deliver a sound experience we want to go back into eagerly, that trigger emotionality and wow effect, in a well balanced but very engaging way. This can be achieve in all tonal balance possible.
COMPARISONS

VS MANGIRD XENN UP (1DD+4BA+2EST-700$)
The Up are more of a crisp smoothly balanced W shape which make the Thunder feel mid centric and warmer, yet not lacking in layering capabilities.
Bass of the Thunder is warmer, looser and less punchy than more define and texture bass of the UP which seem faster and more controlled. Mids are thicker, darker, less transparent with more smoothed upper mids, so attack is less edgy and define, more foggy, layering while decent is more muddy and less clean in separation than UP. Up have thinner but more textured timbre, it have greater sens of openess too and imaging for mids range is notably superior, less dark and warmly saturated.
Treble is notably more extended, crisper and sparklier with the Up, again ,Thunder have a thick presentation, smoother and fuller sounding treble but less sharp in resolution, less define in attack, less generous in micro details. Sens of air is very present with the UP while lacking with the Thunder. The EST of the UP certainly add more brilliance and well felt attack timing, which is lacking with the Thunder.
Spatiality is notably more open, wider, taller and deeper with the UP, while more intimate with the Tunder, so with the Up you feel in front of stage and with the Thunder in middle of the band.
Imaging is superior in all department with the UP, both in proper spacing for separation and proper transparency for sound layering articulation.
All in all, The UP is superior in technical performance byt quite a big margin, yet for tonality it will depend since its very different, but personally i prefer more mature and refined harman target inspire tuning for the UP over smooth mid centric to bassy neutral balance of the Thunder.
VS GSaudio SE12 (8BA+4EST-950$)
Now we have a dynamic driver less hybrid that is notably more vivid, sharp and bright, as well as thinner sounding, more airy, detailed and technical.
The SE12 is all about speed, resolution and snap, it offer spikier W shape balance with faster more define but less extended bass. What hit first is how fuller sounding and more cohesive the Thunder sound, how timbre is more warm and natural but resolution a notch darker on top, again, we have more mids presence and body which make both male and female vocal more enjoyable and wider in presence than S12. Here, we feel S12 is more V shape, then the treble extend furter, open up spatiality in deepness with more recessed center stage. So, overall treble is more thick and organic, smoother and less fatiguing with the Thunder so you can enjoy your music in a laid back way free of fatigue.
Let say if you seek wow effect, the 4 est of the SE12 sure deliver that more than the more understated (and balanced) highs of Thunder. Treble is notably faster, snappier and better separated and define that the Thunder, level of micro details offering is way higher too.
Spatiality is similar in wideness, but taller and deeper with the S12. Imaging is sharper, more accurate, precise and analytical.
There no doubt that technical performance wise, the S12 is from another league, but tonal balance is more cohesive and smoother with the Thunder, yet you most force yourself to be engage within it’s niche, safe and wannabe natural tonality.

VS Fir Audio Xenon 6 (1 kinetic DD+4BA+1EST-3900$)
Ok, we are into big boi battle here and well, only thing these 2 have in common is the overall natural and laiback musicality, presented in a very different manner and tonal balance.
The Thunder is more neutral to mid centric with sub bass boost while Xe6 is more bassy L shape to warm W shape. What hit first is how more closed and intimate sound the Thunder compared to wider more open and holographic sounding Xe6.
Then it’s the bass, which is more boosted in punch, deeper in rumble and extension and more physical with the Xe6 (especially with bass tuning module), the rumble is more sustain thich and vibrant, it feel better layered too, the kinetic DD make us think their 2DD in there, bypassing limit of lower end acoustic law. With Thunder, kick and sub bass line can feel on same level and lack proper articulation difference in dynamism, while the Xe6 can offer both full bodied bass line and kick punch without canceling each other dynamism.
The mids are notably fuller sounding and more natural, vocal blossom in a wide way and feel more compressed and artificial with the Thunder. Timbre is denser and better in timbral balance fullness. Its not as detailed and transparent, yet, sound layer have more space for proper articulation.We can say Focus mode is slightly more similar in tonality, but suddenly darker, so again, its Harmonic mode i compare too here. Treble is the part we technical performance is superior with the Thunder, yet, less open and musical as well as less sparkly. EST offer sharper brilliance and more decay to sparkle. When it come to lower treble, it’s smoother too but fuller, so violin sound more natural and bodied, lusher than Thunder. Overall treble is thinner and colder with the Thunder too.
Spatiality is night and day difference here, the Xenon 6 is way way wider and taller, more holographic and center stage isn’t as recessed so it’s a bit less deep than Thunder that have a ”tunnel vision” spatiality.
Imaging is more realist with the Xe6 but your even more in middle of music, it’s more 3D and holographic, while it feel more static with extra highs positioning for the Thunder.
All in all, the Fir Xe6 sound more musical and less technical than the Thunder, offer more mids body and lush presence as well as more physical and punchy bass experience and smoother but sparklier treble. Their no doubt the musicality is way more engaging and emotional with Xe6 and could justify an impulsive car selling to enjoy this sound experience, while for the Thunder I will not even sale my rusted old bike.
CONCLUSION

The Aroma Thunder are ”Jack of all trades, Master of None” IEM, and being so at very high asking price is not really a good news.
If you are seeking for wow effect or intensely engaging or emotional musicality, look somewhere else.
If your seeking for a safe tuning that can go from clean transparent U shape to warm gently bassy L shape, this might be an interesting buy, but at this price the sound benefit is very low or inexistant.
My biggest qualm about these is small soundstage, poor bass separation and thin mid range (especially in Harmony mode)
And well, the price, if i can omit thinking about sound value even in term of musicality my subjective enjoyment isn’t met, it lack dynamic heft, mids presence and fullness and spatial wideness.
All in all, it’s not an IEM I would suggest to anybody caring about their hard earned money.
The Mangird Xenn Up can be found for 5 times less money (550$ on Ali) and is superior in all department to the Thunder.