Preamble
Thank you to @Damz87, MiniDisc Australia (http://minidisc.com.au) and Fir Audio themselves for arranging this Australian tour of the Fir Audio RN6, XE6 and NE4.
The technology involved in the production of personal music listening, specifically transducers or IEMs is hardly a novel concept at this point in time. Reiterated countless times, one would believe that there is likely little room for innovation for such a mature device. However, there remains those at the ‘frontier’ of the audio space, looking to implement new and exciting technologies for their devices in order to separate themselves from the market. Today’s review concerns a device that is the flagship of what the brand terms to be their “Frontier” line. The Xenon 6 commands a hefty price point for an IEM but in return promises an audio experience unlike any other. And so, I wish to explore whether the XE6 represents the frontier spirit, exploring unprecedented territory for the IEMs to succeed it, or rather, represents the video game “The Oregon Trail” in which I have died from dysentery.
The Factual Stuff
Similar to the RN6 that I have reviewed here, the XE6 utilises a 6 driver setup. 1x dynamic driver implementing their Kinetic Bass feature, 1x BA for lows, 2x BA for mids, 1x BA for highs and 1x electrostatic for highs.
These drivers are housed in a polished stainless steel shell finished in gold rather than the machined aluminium in the RN6.
The XE6, like the RN6 utilises ATOM modules, utilising interchangeable modules to provide varying levels of noise isolation and in the process, altering the sound signature of the XE6.
What are ATOM modules? Well the XE6 features a pressure relief system that utilises a number of modules to alter the amount of noise isolation and therefore impacts the sound signature of the XE6. The modules are:
- Gold = 17dB isolation;
- Silver = 15db;
- Black = 13dB; and
- Red = 10dB.
As such, the XE6 is a vented IEM that seeks to alleviate pressure in the ear for long listening experiences.
Otherwise, the accessory package in the XE6 contains a handsome leather case, a variety of tips, a cleaning brush, a 4 wire cable terminated in 4.4mm and 2-pin.
The Opinion Stuff
Sound:
The following review was largely conducted using the silver module
Bass:
The XE6 provides a unique low-end experience by virtue of its kinetic bass function. The rather large dynamic driver combined with its open design imparts kinetic energy into the ear and provides a bass that is physical and that you can indeed “feel”. Describe this to anyone without knowledge of the price point nor experience with the IEM itself and I would venture to say that they would have the idea of a terrible Bluetooth speaker physically distorting and shifting slightly on the table whenever a bassline comes in. But the reality of the matter is that the XN6 manages to maintain a level of control and detail to its bassline that defies conventional thinking. The bass frequencies are tight, controlled, fast and highly detailed. The quantity is not lacking either, with sub-bass frequencies such as those in “THE PLAN” from the TENET soundtrack providing a low-end thump that is visceral. Mid-bass in the XE6 is similarly impressive, with songs such as a “Before Dawn” by Slander, which has a constant mid-bass beat throughout the song presenting with such authority and speed that puts many other IEMs to shame.
There is definitely a healthy amount of bass boost both in the sub and mid-bass frequencies that imbues a tremendous sense of presence to whatever it is that you are listening to. Despite this healthy boost, it remains detailed, textured and rather speedy in its quality. I do not wish for you, the reader, to come under the impression that these are the equivalent of a subwoofer. The XN6 remains inevitably an IEM but provides through the dynamic driver, a bass response that seems to straddling the fence of “this bass is punching you in the face” and “oh wow this bass sure is neato”.
With this generous of a bass boost, there is a healthy colouration of the entire frequency response, imbuing a warmth to all music that you listen to and as such there is a loss of perceived clarity but a imparting of a tremendous note weight.
Mids
By virtue of the aforementioned bass boost, the mids receive a dose of warmth and presence. Male vocals seem to receive a tremendous amount of note weight and this becomes readily apparent in duets wherein the male vocalist receives an almost rumbly quality to their tonality compared to female vocalists. It is not a jarring difference but something that is definitely noticeable. Songs such as “Out of Time” by the Weeknd has an old-school sample and a rather forward male vocal line throughout, the warmth and smoothness of songs such as this is a very addicting experience wherein everything seems weighty and impactful.
Instruments residing in this region also receive some ‘guts’ in that guitars, pianos and the like feel very visceral in their presentation, there is some authority to each strum and keystroke that presents itself very pleasing to the ear but not exactly the most neutral presentation.
Female vocalists receive the short-end of the stick when it comes to the Xenon 6, perhaps by virtue of the warmth and body imbued by the bass boost. Female vocalists seem to lose a bit of shine and sparkle to their voice and feel almost slightly veiled in comparison. Throwing on some very shouty and somewhat sibilant female vocals do not elicit the same spine tingle that other brighter IEMs present. This will be a bonus to some more sensitive audio enthusiasts but for me there is a missing x-factor for a female vocalist ascending into a heady falsetto or are simply belting.
Overall, the warmth and darkness of the Xenon’s tuning imbues a strong level of weight and body to instruments and vocals residing in the mids but detracts somewhat from those sitting in the upper region of the mids.
Treble
The keywords of ‘dark’ and ‘warmth’ so far would lead you to believe there is a distinct lack of treble response and to that I would say, no, not really.
Despite former statements that there is a missing sense of sparkle with female vocalists, there remains rather good treble extension and a great sense of drama with instruments residing in the upper regions of the frequency response. Cymbals crash and synths spike into almost sibilant territory but presenting that goosebump inducing sense of enjoyment. “The Demon Dance” by Julian Winding has an ever-present brush on a hi-hat throughout the majority of the song. On less well-tuned IEMs, this is a rather recessed afterthought but the sense of tingle of this seemingly innocuous instrument on the Xenon 6 is rather excellent. The contrast that you get with the aforementioned booming bass is also a part of the charm of the Xenon in that when one element is heightened and juxtaposed with its seemingly opposite counterpart, they are both highlighted. Where the Xe6 seems to fall short of its cousin and perhaps other TOTL IEMs is a sense of airiness. The XE6 seems to be rather confined and rather than have an ever-present sense of brightness and elevated ‘detail’, the treble seems to strike out of nowhere. There is no sense of fatigue with my playlist, even with songs that try to eek out sibilance where possible. But unlike tranducers with an overly smoothed and rolled off treble response, the XE6 remains willing and capable to flex its muscles in this region, it just doesn’t want to most of the time.
Overall, the charm of the treble of the XE6 lays in its ability to contrast against the elevated bassline rather than stand out of its own accord. It is not the strong suit of the XE6 but remains distinctly enticing in its ability to come out in the mix when needed.
Technicalities
First and foremost, the resolution and detail provided by the XE6 remains distinctly wonderful. However, unlike its cousin, the RN6, the XE6 doesn’t have the tuning to present a highly detailed and unforgiving reproduction of music. It is slightly smoother and warmer that the RN6 and as a result, detail doesn’t jump out at you so much but rather effortlessly presents it for you to notice at your own leisure.
There is a distinct sense that the mid-bass boost in the XE6 seems to bleed into the mids and whilst I hesitate to describe it as overly boomy or overdone, it does detract somewhat from the ability to discern the micro details within this region as well as the sense of ‘layering’ and imaging. However, the most interesting element of the XE6 is its ability to resolve and reproduce detail in spite of its warm and highly unique tuning approach.
In terms of staging, the XE6 presents a rather intimate staging. It is rather good in extending in terms of width but the depth seems rather shallow. I would liken the staging to a slightly too large recording booth. However, like the RN6, it seemingly adapts to certain music, as orchestral productions manage to extend in a manner that would leave you confused after characterising it as ‘intimate’ following a run of the top 20 pop songs out in the world currently. Despite this, it is not a soundstage monster and remains distinctly intimate and engaging.
Overall:
Bombastic and hugely engaging, the XE6 boosts bass in order to provide tonnes of fun through a warm and weighty reproduction of music. It does so at an almost neglible cost of mid and treble response but for the price, one would have to be immediately sure that this is the sound that they’re looking for.
Perhaps overly coloured to some, the XE6 falls left of neutral but the reward is almost thick and gooey form of sound that is not very fatiguing and contains a strong sense of drama.
It remains technically adept in its ability to resolve but imaging and soundstage seems to suffer from the coloured tuning approach.
Synergy
One thought coming to my mind here namely lessons learnt after multiple DAPs, DACs and Amps plus headphones and IEMs is synergy! Hoping for the one and only holy grail Setup is maybe just a nice wish unless buying according synergy transducers and I don't believe even the best sources are an exception here. There's a reason why people are having multiple devices in parallel or reducing inventory and keeping only the ones with right synergy.
Shanling M6 Ultra
I would characterise the M6 Ultra (M6U) as a smooth, slightly warm source with an increased sense of presence in the mids and a strong note weight.
The M6U combined with the XE6 is basically pornography. You feel slightly dirty after the fact and that’s because this combo is unabashedly indulgent and almost hedonistic in the amount of warmth and note weight imbued into your music. Bombastic orchestral pieces such as “One-Winged Angel” by Nobuo Uematsu feel as dramatic as the final boss battle in a 50 hour long video game would have you believe.
Perhaps not the ideal everyday listen but choral renditions combined with gigantic brass instruments and drums present themselves in an almost harrowing manner. Overall I would say that this is a guilty pleasure pairing rather than one I would have on for a relaxing listen after dinner.
Chord Mojo 2
I would characterise the Mojo 2 as a very, very slightly warm neutral tonality with a more natural reproduction of instruments and voices with no DSP enabled.
The aforementioned explosive nature of the M6U’s note weight seemingly floated away for something more reasonable for a regular listen.
The more neutral presentation compared to the M6U seemed to heighten my ability to pick out microdetails in the periphery of the stage and seemed to present a more flatter, more wider stage than the M6U. The Mojo appeared to largely calm the more bombastic pairing of the M6U. It remains distinctly warmed and slightly dark to the ear when comparing it to other IEMs but the pairing of the Mojo and the XE6 seemed to present a more vanilla and linear presentation that would be better suited for an everyday listen.
Overall there is not faulting this particular pairing especially with the benefit of the DSP features of the Mojo that will allow users to fine tune their listening experience.
Cable Madness
The Fir review kit arrived at the same time as a range of cables from Effect Audio and so I thought it best to compare these.
Ares 8W:
This is just pure hedonism at this point. A lush, warm and bassy IEM combined with 8 wires of copper lends itself to even more mid-bass punch and even more note weight. The upper mids do become rather recessed and when compared to the stock cable, the technical abilities of the Ares are about on par or maybe slightly better. This is not for the faint of heart and as such, synergistically, I would say not a great match unless you’re looking for nothing but bass.
Cadmus 8W:
The Cadmus provides a more even-keeled approach to the XE6 by injecting some air into the upper regions of the frequency response. Female vocalists become more forward in the mix, mid-bass is about the same or reigned in slightly and there is greater emphasis on the sub-bass lending itself to a more clear and neutral reproduction of music. This shift in tuning provides greater perceived detail retrieval and a sense of a deeper, more clearly defined stage. Overall, this cable pairs quite well with the XE6 if you’re looking to tame some of the qualities of the XE6’s coloured tuning, but then again, where’s the fun in that?
Code23
There is a tendency for certain attributes to be lended to certain material choices. The Code23 seemingly dispenses with that. Despite utilising a ‘copper core’ cable, the Code23 greatly thins out the XE6 in a manner that brings it closer to a more lean and neutral reproduction of music. Mids are brought to the forefront of the mix and there appears to be a tremendous expansion of the stage, both in terms of depth and width. Bass is tamed and there is a slight sibilance to certain higher-register female vocals in my testing.
Compared to the stock cable in a quick A-B, one would think that the Code23 is almost too thin and anaemic compared to the big body warmth of the XE6 but longer listening periods really make you appreciate the detail and resolution chops of the Code. Overall, I feel that this is going too far in the opposite direction to what Fir likely had in mind with the XE6 but there may be proponents for this approach to synergy.
Fusion 1
The Fusion 1 features a rather generous mix of materials in its composition, and it seems to work very well with the XE6. There is an expansion of the stage, a retention of the wonderful bass and all without descending too far into leanness. Mids are forward but not to the extent of the Code23 and there is still a sense of warmth and lushness to the XE6 with the Fusion that I feel represents the most balanced approach to the XE6 in this lineup of cables. I would heartily recommend the Fusion with the XE6 simply on the basis that it seems to just work well across the board instead of not doing enough or doing too much in respect of the tuning profile.
Comparisons
Vs RN6
The Rn6 and the XE6 come in at similar price points and the sound differences are similar in a number of respects with their tremendous bass response and somewhat coloured tonality. Where they differ however is their emphasis. The XE6 closes off the stage and chucks all the instruments into the recording booth with you where as the RN6 neatly arranges all of the instruments on a rather generously adorned theatre. The RN6 presents music with a huge injection of airiness and speed in the low-end that feels wonderfully resolving and detailed. It sits closer to neutral when compared to the XE6 that is warmer, darker and more bombastic than the flighty and more ethereal RN6.
Technically speaking, both are excellent in their ability to resolve even the most busily produced tracks. However, by virtue of the RN6’s tuning there is an apparent benefit to accurately image certain instruments and vocal ad-libs within a song, there is a greater sense of layering to the music compared to the XE6.
Overall, I would state that if you wish to be attacked by your music and be 100% engaged in whatever you’re listening to, the XE6 is a guilty pleasure machine that injects dopamine through your eardrums. The RN6 is a more refined and snooty type of IEM that rewards keener critical listens and is perhaps a more neutral monitor than the XE6.
Vs MEST MK3
(noting that this is off memory and notes)
The MK3 was my initial dip in the pond of double kilobucks and considering the XE6 is a quadruple kilobuck, I thought I would make the comparison on a value basis.
Where the two IEMs are similar are in their party piece, the leveraging of bone conduction, albeit via alternate means. The bone conduction driver in the MEST MK3 presents a unique experience that seems to provide a benefit in terms of increasing layering and imaging capabilities and generating a stage effect that cannot be defined as “in-ear” by any means. The XE6 utilises an open dynamic driver to make contact with the ear and presents a more prominent “physical” effect of bone conduction. The efficacy of this approach seems to be a boon to the bass wherein the physicality of the sub-bass and the energy of the mid-bass are heightened by the kinetic bass driver. The BCD takes a more subtle approach across the frequency response curve that would potentially lead one to believing it is doing nothing at all. Overall, the XE6 leans harder into the warm sound signature than the MK3 and does so at no cost of bass quality. The MK3 had great bass but it ultimately was not the standout. Resolution wise, the XE6 renders detail in an alternate manner. Whereas the MK3 seems to layer music in a readily digestible manner, it remains slightly incoherent as I found myself thinking “oh I see what the BAs are doing and here comes in the ESTs” whereas the XE6 feels more like two large speakers doing all the work. I am essentially trying to say that the XE6 has better resolution (from memory) but this doubly impressive for doing it in a more natural and cohesive manner.
Overall, the law of diminishing returns seems to be full effect at this price point. I deducted points from the MK3 for not being good value but given some used prices I’ve seen it represents an obvious jump from kilobuck whereas the XE6 (perhaps hampered by its very coloured tonality) is less of an obvious jump except for that delicious bass response.
Vs Neon4
The most neutral out of the trio of FiRs that I have in for review, the Neon4 provides the closest to a more linear frequency response curve and does not go too far into the coloured tonalty region. With that being said, the Neon 4 still manages to provide a bassier and warmer experience than more reference IEMs in the market but when compared to the likes of the XE6, it is practically ruler straight. This tonal approach provides less emphasis on the bass and seems to heighten the mid range and the treble in a manner that creates a less overwhelming musical experience. The kinetic bass on the Neon 4 still provides a great sense of physicality but to a far lesser extent than the XE6.
Outside of tonality, the technical performance of the Neon4 is no slouch despite being significantly cheaper than the XE6, but even with the latter’s rather extreme tuning, it manages to eek out greater details and is able to image better upon a critical listen.
This is an unfair comparison but nonetheless, the XE6 seems to be more characterful and also technical at the same time.
Quality of Life & Value
The XE6 is a rather thicc boi shell. Less tapered and more angular and girthy, the XE6 shell will inevitably pose an issue for more picky ears. This is compounded by the fact that the XE6 shells are constructed from stainless steel, far heavier than the aluminium shells on the RN6 or resin in most other IEMs in the market. This reduces the ergonomics of the XE6 and requires a rather good seal with whatever eartips you use in order to be tenable for longer listening periods or for use while on the move.
The various atom modules provide you with the ability to alter the level of isolation of the XE6 which is vented, whilst altering the tuning.
The price of the XE6 is definitely the sore point of the IEM. At a rather hefty price of 3899 USD it would be remiss of me to recommend this as the best IEM in the world. The tuning of the XE6 is very coloured as far as IEMs go, with the aforementioned bass boost and oddities in the treble yielding that this is not made for the everyman. It definitely resolves and provides details like I would expect a TOTL IEM would but overall, the tuning is so skewed that I would state that a demo before a purchase is a non-starter.
And when you move past that, you are inevitably receive a specialist, hardly something that I would use for any and all music in my rather varied library but something that absolutely shines with modernly produced music, specifically more poppy or EDM tracks. Paying as much as you do for a XE6 to be absolutely wonderful for only part of the time is something that I cannot recommend. As such, I would say that this is not the value proposition you are looking for, even if you’re looking for something specifically in this price category.
Conclusion:
Ultimately, the XE6 presents an odd approach to the TOTL range of IEMs. Eschewing a safer tuning to appeal a broader audience, the XE6 leans, and leans hard into providing you with a very, very generous bass boost.
This combined with its rather outrageous price presents a very, very poor proposition to blind buyers and I would heartily recommend you auditioning these prior to buying.
In any case, where the XE6 excels is its ability to remain great in terms of technicalities with excellent imaging and resolution with its very coloured and very warm signature.
This is nirvana for a specific person and perhaps hell for a lot more people than not and as such, I cannot heartily recommend it.
