
Acknowledgement
I would like to thank Ken Ball, Caleb Rosenau and the team at Campfire Audio for giving me the opportunity to hear their new Solaris 2020 model. The unit was provided free of charge for the purpose of review. The opinions stated here (however misguided!) are 100% my own, and no incentive was provided for a positive review or writeup. I am a current owner of the “original” gold Solaris model.
For the avoidance of doubt, I have put in excess of 400 hours of use on the 2020 model before finishing this review. The initial 150 hours was done using a playlist of 1000+ tracks on constant rotation. This is the recommended “burn in” time suggested by Campfire. While I’m neither “for” or “against” the burn in phenomenon, there are reasons that CA think this is required (please see my original Solaris review for more in depth explanation around why) so I did this to remove it from the equation when writing up my impressions.
I would also like to apologise to the CA crew for the lateness of this review. It’s fair to say that my personal 2020 experience has been somewhat of a mixed bag, encompassing some major Covid and non-Covid related low points (losing my job unexpectedly in the middle of the pandemic was a particular highlight) and some major highs (becoming a father). I have had to put my audio reviews on hold while I dealt with all of the above, but throughout it all, listening to music was the one major escape, and a way to reconnect with a bit of emotional and mental normality. Most of that has been done with the Solaris 2020, so I owe a debt of gratitude to all those involved for creating a piece of audio equipment that is so emotionally engaging, and one which has personally helped me see the light in some dark times.
Don’t worry, the rest of the review will be a mixture of the usual irreverent / irrelevant commentary, mixed metaphors and general word salad, but I just wanted to say thanks to Ken and Caleb in a personal level for making something that has had a significant positive impact on my 2020 experience.

Rating and tech specs


Introduction
The Solaris was introduced by Campfire Audio in 2019 as their hybrid in-ear flagship, sporting four drivers in a hybrid configuration and utilising various pieces of technology from across their product range. The original model packed in their 10mm ADLC diamond coated dynamic driver, their “polarity chamber” tuning waveguide and the now ubiquitous TAEC chamber to give the highs some air and sparkle. The 2020 edition sees the return of all these features, with the TAEC chamber sporting an upgrade to a ceramic material and the inner workings of the IEM now being fixed in a 3D printed “solid body” to allow for a more precise internal geometry and placement of components.

Build quality and ergonomics
If you are talking about the original Solaris, there is no getting around the obvious elephant in the room – it is one big IEM. JH Audio big. An elephant trying to squeeze into a phone box big. A orange toupee wearing politician’s ego big. Big enough to generate it’s own gravity big.
Now, this wasn’t a problem for me personally. I have ear canals only marginally smaller than a subway tunnel, and a head the size of a small bovine, so I always found the OG Solaris comfortable to wear for extended periods, although I did end up putting some custom silicone eartips on it to aid stability. Why do I mention this, you might wonder? Well, CA state that the 2020 model is approximately 20% smaller in size than its golden predecessor. That might not sound like much, but in practice it makes a huge difference to the wearability of this IEM.
The new shell design takes the comfort up to a new level, allowing for a deep insertion with the included foam tips that provides a stable and comfortable fit with a much lower profile in the ear than the original model. The angle of the nozzle and the chamfering of the inner surface of the IEM gives a very smooth and ergonomic fit in the ear, and the reduction in weight of the metal shells also makes the 2020s a lot less apparent in the ear when using them for extended listening sessions.
I imagine there will be some people for whom the new design won’t work perfectly, but for me this marks a notable step up towards a more “universally acceptable” shell design for this model, and should leave most users more than satisfied.
With regards to the build itself, the 2020 opts for an all black shell in a glossy PVD finish (that’s vapour deposited, just in case you were interested). The shell has plenty of intricacy, with fine grooves like a vinyl record adorning the inner shell surface, giving the smooth contours of the inner face a nicely textured feel in the hand. Slightly deeper and wider grooves make an appearance on the flat sides of the shell. The faceplate is solid black, with a small embossed CA logo in the bottom corner of the face the only obvious identifying mark.
Compared to both the OG and more recent special edition versions of the Solaris, the 2020 is practically austere, all classy lines and shiny car-finish black metal without any obvious decoration to distract from the Model T Ford aesthetic. I really like it – paired with the new smoky grey version of the ALO SuperLitz cable this IEM is the closest thing to a Stealth Bomber you can fit in your ears.

Initial impressions on sound
The Solaris 2020 is unsurprisingly similar to its golden predecessor, with a balanced and spacious sound that leans more to the musical side of the spectrum rather than analytical. It is broadly W shaped, with some definite sculpting going on between sub and mid bass and through the upper frequencies, but nothing that takes it drastically away from the middle ground in terms of balance.
Note size is on the large side, with the Solaris presenting a bigger than average sonic image that expands out centrally in all directions, giving music a super-sized sense of scale. Stage size is accordingly big, but not 64 Audio / ADEL type massive, stopping a little distance outside the imaginary confines of your skull. Combined with the large notes, it allows the Solaris to pull the listener towards the music and present in a very intimate manner without feeling crowded or cramped.
Bass is slightly north of neutral, keeping a good balance between sub and mid bass frequencies and giving the sound a solidity that underpins the rest of the frequencies nicely. It isn’t a fat or chubby sounding low end, but there is enough meat on the bones to keep most listeners more than happy, and definitely more so than the original model. Campfire have addressed the mid bass quantity (or subjective lack of) in the original, and the 2020 feels a little more balanced and substantial as a result.
The midrange is placed in line with the bass and treble, with a subtle dip throughout the upper bass to lower mid transition to keep things cleanly separated. Like the bass, it is meaty enough without sounding thick, presenting guitar and vocals with a raw edge that cuts through the sound without sounding harsh or hot. It reminds me very much of Final Audio in that respect, dressing notes with texture and resolution to provide a little more emotional resonance and weight than you would get in a strictly flat or neutral tuning.
Treble is extended and has the classic CA sparkle, although not to the extent of something like the Andromeda. It isn’t a linear progression up from the mids, with some careful tweaking taking place, but overall it does sit roughly in line with the other bands, not feeling quite as emphasised as the original model in comparison. If you have heard one of the other high end CA models in the past, you will know what to expect here: treble that is airy and expansive, but not soufflé-light as a result. It isn’t overcooked in terms of quantity, but it definitely feels like a focal point for the tuning as a whole.

Bass
Looking at the individual frequency areas in more detail, the 2020 feels like it has a tad more mid-bass quantity than the original version. It still retains the woofer like quality to the low sub frequencies, providing a sense of physicality and slam that is almost disproportionate to the quantity of sub bass being produced. It lends a very “speaker like” and grounded feel to the presentation, providing substance without a huge amount of weight to the notes.
Much like its golden sibling, the tuning in the sub frequencies is almost the inverse of a typical BA style tuning, prioritising physical impact over sheer quantity. The 2020 gives plenty of physical slam, but only a neutral to sightly thicker than absolute neutral quantity. In terms of extension, the Solaris does still dig loooow on tracks like “Why So Serious?”, but the thrumming is more towards the polite end of the spectrum rather than head-rattling. This has extension in spades and is definitely a far cry from being an anaemic or flat style of bass tuning, but it’s safe to say this isn’t an EDM bassheads will flock to in their thousands without some serious EQ.
In terms of bass quality, the 2020 is comfortably up there with the best DD-driven models on the market at present (in my humble opinion, anyway). The diamond coated driver shows its pedigree here, exchanging some of the raw decibellage of the Atlas (where it is also used) for a higher level of texture and refinement. Bass is tight and snappy, digging plenty of detail out of the lower ranges. Listening to “We Shall Not Be Moved” by Mavis Staples, the fuzzy double bass line and ridiculously deep baritone voice lurking in the chorus line both drip with definition, eking out some impressive clarity. There is space between the individual bass notes that provides the basis for excellent resolution of smaller details and nuances, allowing the Solaris to present plenty of fine micro-detailing without it getting masked in the overall sound.
Listening to a few of my other go-to test tunes, “Hello, It’s Me” by Sister Hazel is a track that emphasises texture, the oh-so-slinky bassline that defines the track feeling large and slightly raspy, giving an almost powdery feel to the bass. It feels taut and nimble, but without some of the chocolatey wetness that can come across on IEMs with a looser presentation. It still does a good job of filing up the lower half of the sonic landscape, but there is a sense of control that permeates the presentation, keeping a tight leash on proceedings.
“Bad Rain” by Slash again emphasises the definition, but this time carrying a little extra weight in the aggressive bass guitar and drum patterns that drive the song along. The bass digs deep, sounding thickly textured and captures the punky energy of the track nicely. The kick drum has a solid feel to each impact but doesn’t boom as much as it can on bassier setups, highlighting the control that defines the Solaris’ low end. The rasp of the bass guitar strings as they vibrate comes through cleanly, giving a dry and almost powdery sonic texture, the equivalent of some aural sandpaper to contrast with the richer and wetter sounds above
Overall, the bass is very much in the Goldilocks zone for me. It has just the right amount of meat in the mid and upper bass frequencies to give a little substance and warmth to my music, and enough physicality and oomph lower down to really anchor the rest of the sound. It isn’t a bass monster by any stretch of the imagination, and the sub bass definitely errs more towards reserved rather than rumbling, but the almost woofer-like quality and slam imparted gives the 2020 a unique presentation for me, and one that feels pretty perfectly judged for most types of musical enjoyment.

Mids
Like the original Solaris, the midrange is covered by one full range vented balanced armature driver. I believe the model of driver has been changed out from the previous Solaris design, and certainly in terms of sound this is the most noticeable tweak when it comes to tuning. The mids take a more central position, pushing up in line with the bass and treble to provide a more balanced “W” shape this time round.
There was a little “debate” among various areas of the audiophile internet around a perceived scoop-out in the midrange on the previous model that was used to push instruments slightly behind the vocal. It seems that this observation was mainly noticeable on certain genres of music like K-pop and J-pop – I personally never found it to be a noticeable issue with any of the musical genres I listen to (mainly guitar based rock and acoustic type music and a little OST and electronica). Either way, the new model seems to have addressed that particular concern, with a slightly more linear midrange, lending voices and instrumentation a thicker and more solid feel.
This is still definitely identifiable as a “Solaris” type sound signature, but the extra meat in the midrange adds just a little more substance and balance to the tuning without drastically deviating from what came before. The bass to midrange transition is handled well, with no obvious crossover between the drivers (which there shouldn’t be, given the relevant BA is running full range). The controlled quantity of bass ensures there is no bloat or bleed into the lower midrange, and the vented armature provides a weighted and clean tone to both instrumentation and voices.
Positionally, the mids are placed in line with the bass and treble and pulled forward towards the listener, lending some intimacy to vocal performances. There is a very good TOTL level of clarity and detail on display, but the Solaris carries a hint of rawness along with the resolution that reminds me a little of the old Final Audio midrange tunings. This is an IEM geared more towards emotion than analysis, despite its technical merits.
Running through some test tracks, the Solaris returns a unanimously enjoyable experience. Starting with vocals, “What Good Am I?” from veteran crooner Tom Jones’ excellent “Praise & Blame” release paints a rich yet delicate image of Jones’ famous baritone. Framed by some sparse drumming and a similarly subdued acoustic guitar, the Solaris allows the listener to focus on the incredible texture and range in the vocals on this track, pushing the singer right up into the front of the stage and presenting a sonic image almost as big as the singer himself. Each subtle intonation and inhalation is captured, with the 2020 giving a velvety richness to each note and allowing the listener to picture the recording space, giving Jones’ voice a three dimensional quality. It manages to capture both the emotion and the bombast of the delivery, thick enough to carry the weight of feeling but light enough to also reveal the nuance.
Sticking with the classics, “And The Grass Won’t Pay No Mind” from the recent Elvis Presley collaboration with the Royal Philharmonic is another impressively rendered track. The Solaris captures the subtle hint of rawness and emotion in the King’s voice as it cracks around the 1:42 mark, sucking the listener fully into the delivery. Otherwise, Presley’s voice is rendered as smooth as a sheet of silk woven entirely out of butter, sounding both meaty and refined at the same time. The midrange isn’t the densest or thickest you will hear, but the 2020 manages to convey just a little more solidity here than the original version, giving the sound an overall more “filled out” presentation that suits the additional bass presence well.
In terms of instruments, acoustic guitars sound sweet and precise, standing out against the background with a little of that classic Andro style “shimmer”. Each pick and strum on tracks like Andy McKee’s version of “Everybody Wants To Rule The World” stand out clearly, keeping everything neatly separated and distinct without sounding disjointed. Electric guitars sound more weighted, with plenty of chug factor on the right rock tracks. Again there is a nice sense of clarity and separation, the Solaris providing a muscular but not overly thick presence, with a nicely old school “analogue” tone to some classic rock riffs that reminds me of a wall of overdriven Marshall amps in full flow.
There is more emphasis on the leading edge of the notes than the body, but the 2020 doesn’t sound lightweight, carrying enough heft to keep bands like Metallica crunching away in the ear. Crunch is actually a good description of the overall tone, with tracks like “Nineteen Eighty” by Joe Satriani and “Shadow Life” by Slash both fizzing away with bags of energy and bite, with a pronounced emphasis on attack. The Slash track is particularly taut, with the staccato riff stopping and starting on a sixpence, giving the 2020 an extra splash of anima compared to the original model.
Timbre on other midrange instruments is fairly true to life, with cello and violin carrying plenty of fine texture and an engaging hint of warmth to the tonality, balanced out by the slight edge of rawness that provides the detailing. I’m not a huge classical music afficionado, but the 2020 seems to do well with this genre, providing a sense of scale and power to the strings and brass that evokes full sized headphones at times.
Looking for harshness and sibilance, “Whiskey And You” by Chris Stapleton is up next. The singer’s gravelly roar is in full effect, evidencing plenty of rawness but managing to steer clear of the jagged edges that can show themselves on some of my IEMs. It sounds emotive but not harsh, treading a fine line between retaining the detail and applying a little polish to the inherently hot mastering. It’s well done.
My other tester for hotness in the midrange is the Slash track “Starlight”, which is a collaboration with Myles Kennedy. It starts with a deliberately dissonant electric guitar into, and builds into a helium fuelled wailer, Kennedy’s singing hitting the upper stratosphere. The 2020 handles this with a mixture of edge and refinement, giving plenty of bite to the instrumental harmonics but not scratching at the inner ear in the process. There is enough weight to the vocal to keep it soaring rather than searing too, with the Solaris never threatening to turn this track into an unpleasant experience.
The subtle detail and room noises in the background are also readily apparent here, emphasising the resolution the Solaris is capable of. You can hear the barely audible scuffs at the end of the intro, and the soft vibrato in the guitar notes as the bassline enters the track, giving the track a good sense of immersion and texture without distracting from the main core of the music.
Overall, the midrange sits firmly in the Goldilocks zone – emotional but still revealing, meaty but not lacking bite, slightly sweet but not saccharine. It provides a nice balance between technical capability and musicality. It is the area that send to have benefitted most from the internal redesign and tweaking, bringing the original sound signature up a small but notable notch. Nicely done.

Treble
Given that this is another model that uses the proprietary Campfire Audio “TAEC” system (Tuned Acoustic Expansion Chamber), the upper frequencies are classic CA. Light and airy, with plenty of ethereal “sparkle” that is difficult to quantify but easy to identify. In terms of emphasis, the highs are extended but not particularly emphasised, sitting more or less in line with the other two bands on the stage. Apart from the slightly different relative stage positioning due to the fuller mids and bass underneath, my observations from the original Solaris review with the same test tracks still hold true, so the same music has been used for comparison.
There is a crispness and lightness to the highs that makes the music sound wide open and airy, but also a solidity and thickness of note that stops it from completely floating off into the upper atmosphere. The effect is more reminiscent of a concert in a wide open field than a large auditorium to my ears – sounds drift away from the listener and fade out, but lack the defining boundaries of a large space to give them that reflective sense of scale.
Going back to “Starlight” by Slash, the dissonant guitar harmonics in the intro are sharp but still weighty, glistening in the ear with an analogue tone that stops them grating. “Chi Mai” by the classical fusion violin duo Duel sounds majestic, the mix of fluttering synth notes and sharp and emotive violin building to a sparkling crescendo. Violin sounds rich, the vibrato of finger on violin neck coming through clearly with each note that is bowed or plucked. The electronic accompaniment occupies the space above, lightening the tonality without overpowering, providing just the right level of accent to the sound.
“Go” by The Chemical Brothers follows a similar theme, the swirly keyboards that kick in around the 1:20 mark whipping across the top of the soundscape, opening up the higher octaves without sounding overly bright. It envelops you, bringing the height of the stage into full relief. Treble is solid but extended, carries sparkle but isn’t overly thin or delicate (unless that’s the way it is recorded in the track) and is absolutely packed with fine detail and texture.
Despite saying that the treble has weight, this isn’t a dark monitor by any means, and for fans of an ultra dark or rolled off treble tuning, the 2020 revision of the Solaris still shouldn’t be at the top of your wishlists. It extends effortlessly past the upper reaches of my hearing without any apparent strain, but doesn’t lose it’s analogue tone while doing so, not resorting to any particularly obvious spikes or tuning trickery in the upper ranges (that doesn’t mean it isn’t there, but if it is, it’s well done). This is pure treble, with plenty of inner resolution rather than specific frequency sharpening, making it easy to listen to for extended periods without any dose of fatigue.
If you are looking for the unique treble capability of the Andromeda series, the Solaris won’t be the IEM to take that particular crown, but if you are happy to take a meatier and more analogue tonality in exchange for some of that sparkle, the Solaris is an exceptional IEM in this frequency range. It doesn’t redefine the presentation of the upper ranges like some of the more recent technological advancements like the Sonion e-stat drivers or the various tubeless/top-firing/otherwise deconstructed armatures appearing in other brand flagships, but for sheer enjoyment and balance the 2020 is still something pretty special here.

Soundstage, separation and imaging
This is another area where the 2020 revision diverges slightly from the OG model, due to the more linear overall tuning and fuller midrange. The stage the 2020 constructs is wide, but notably less broad than the original model, reaching out sightly outside the ears in both directions. It trades this for a better sense of depth, driven by the additional fullness in the bass and midrange to give a more “dimensional” or holographic aspect to the sound.
Like its predecessor, the 2020 doesn’t give a feeling of huge vastness in its staging, mainly due to the size of the individual notes on the stage. It feels almost as if the music had been blown up with the classic iDevice “pinch to zoom” gesture in the ear, but while still being able to see the full picture. It’s this sense of scale which leads to an almost speaker-like feel to the presentation, the music giving the impression of filling the available space around the listener’s ears without seeming crowded or claustrophobic. This is an area that the 2020 actually betters the already impressive OG model, providing more size and weight to the oversized image. However, due to the sightly smaller stage dimensions, the 2020 loses out a little in terms of separation, planting the various strands of musical info a little closer together on the stage, without the upper-mid dip and leaner low end to keep everything further apart.
Playing something like “Trouble” or ”Shelter” by Ray Lamontagne, the hard-panned drums and bass parts still push outside my head, but don’t feel disconnected or distant from the centre image. With regards to imaging, this is another area where I feel the 2020 revision has made a small but appreciable improvement. Despite the less obvious separation, the imaging feels more precise, putting instruments and vocals into a definite three dimensional location in your head. This doubles down on the sense of realism the OG was able to achieve, allowing the listener to hear even further “in” to some well recorded tracks, with each instrument possessing more of a lifelike feel as it sits in a specific location in the overall sound.
The original version was a very good technical performer, but I feel the 2020 has made small but significant improvements in all areas here barring separation, which is a more than acceptable tradeoff in my opinion.

Power requirements and synergy
The 2020 Solaris has slightly more “demanding” specs than they original model, but by any objective metric is still a ridiculously easy to drive earphone. Like most CA gear, two paper cups and a piece of string is pretty much all the power you need to burst your eardrums, and also like most CA models packs a hiss like a sack full of snakes at a bootmakers convention as soon as the cable hits the socket of a noisy source. If you pair it with anything less than a jet black output, it will let you hear the noise floor. Personally, I find the hiss barely audible, so it isn’t an issue for me once music starts playing, but if you are someone who needs utter blackness in the background to enjoy their music playback, you will need to think carefully about what sources you match this IEM with.
As stated, the newer model doesn’t need power, but it can definitely handle a higher current output between the 10mm DD and the new vented armature, so I actually find some of the best results come from punchier devices like the Cayin N6ii/E02. With that particular combination, that also comes with increased hiss, so there is an almost inverse relationship between the extra control you can get in the low end and the noise you have to endure in order to get that added “grip”.
One source I do have that had both the power and an almost silent backdrop is the recently released little brother of the N6ii, the Cayin N3 Pro. Driving the 2020 from the balanced out gives a clean, punchy sound with pretty much no hiss and a grippy, chunky texture to the sound that will appeal to people who like their tunings slight more on the dry side. It’s a good pairing.
Lining the Solaris up with a more neutral source line the Cowon Plenue D2 yields a quiet but strangely soulless pairing, the little PD2 not taking full advantage of the emotive sounds that the 2020 is capable of. A much more acceptable pairing is the Sony NW-A55 (running custom MrWalkman firmware). The pocket player from the budget end of the Walkman line actually produces a nicely dimensional sound out of the 2020, with the A55’s meagre driving output producing a pitch black backdrop and still getting the Solaris pretty loud at 50% volume on the pot.
The 2020 model seems to have a different impedance curve to the original, too, not exhibiting any noticeable signature shift between my various sources, which the OG seemed to occasionally be prone to due to the overlapping midrange BA. It also still pairs frustratingly poorly with the ALO Continental V5 amp, however; it’s a musical smash hit in terms of synergy, but just too much hiss to be a workable solution for most people. Like the OG, you could always use something like an IEMatch from iFi to alleviate that, and in this instance it doesn’t have the same effect on the final rivalry as it did with the preceding model, but it’s still a little frustrating.
For my personal preferences, a source that leans towards a thicker and more musical sound would be my suggestion, allowing the full musicality of the Solaris to come to the fore. This is one of those rare synergies where you want to double down on musicality to really get the best out of the IEM rather than trying to flatten it out with a more neutral or sterile sounding DAP or DAC/amp combo.

Tip choice
For the original, this was a source of great debate, with plenty of effort being required in order to find the best fit and sound for each individual ear anatomy. The 2020 redesign fortunately makes that a lot easier – the much improved fit basically opens up the Solaris to a much wider set of tip options.
I’m personally not the biggest fan of the Final E tips provided for this particular IEM, as I find it makes the sound a little too V-shaped for me personally. I much prefer a wider bore tip like JVC Spiral Dots, which keep the unique Solaris balance and allowing for a rock solid insertion and fit. My current favourite however are the CA marshmallow foamies that are supplied, as I feel these give a nice sense of oomph and warmth to the bass without muddying the sparkle up top or blunting the midrange. I believe Ken and Caleb tune a lot of their IEMs using these foam tips, and in this case it shows here.
Long story short – for all but the most demanding or obscure of ear canal shape, the supplied tip load out should do the job nicely for most preferences.

Comparisons
Itsfit Fusion (Hybrid – 1xDD, 2xBA, 1xMagnetostatic) – c. $999
The Fusion is the current hybrid flagship from new Vietnamese company Itsfit Labs, who have been making a name for themselves in the reshelling market in recent years. It sports a similar number of drivers in a hybrid configuration, but pairs two balanced armatures for the midrange with a 10mm dynamic driver for the low end and a magnetostatic tweeter for a unique tribrid configuration. The magnetostatic driver is a close cousin of the planar driver tech note finding it’s way into some in-ear monitors, and provides a very unique sounding take on the upper registers.
Starting with the stage, the presentation is not as wide on the Solaris, but feels appreciably deeper. The Fusion throws its notes out further along the X-axis, but feels more oval in terms of stage depth compared to the more spherical Campfire model.
Tonality wise, the 2020 feels more analogue, with a warmer and more musical approach compared to the crisp sharpness of the Itsfit. The Fusion is definitely the brighter of the two IEMs here, with a presentation that leans a lot more towards a colder U-shape in comparison to the Solaris’ warmer W.
Sub bass is more emphasised on the Fusion, with an additional few dB adding weight to the underneath of basslines and giving an almost club like thump down low. Mid bass quantity is roughly similar on both, sounding comparatively leaner on the Fusion due to the bigger sub emphasis. Quality is similar on both IEMs, with the 2020’s ADLC driver just edging ahead in terms of resolution and texture, but not by a huge amount. Both IEMs can produce good levels of texture and resolution, and can confidently be considered top tier in terms of raw performance, if not here.
Moving up the frequencies, the midrange is similar in emphasis, but positioned a shade further back on the Fusion. The Itsfit model also sounds thinner and more aggressive than the Solaris here despite using two armatures to the 2020’s one, lacking the final dash of raw detail and finesse the the Solaris possesses. It’s probably the weakest aspect of the Fusion tuning, and while it’s far from actually being weak, it doesn’t quite match the more emotional and revealing Solaris here. For fans of a thinner and sharper sound the Fusion will probably better suit those preferences, but just can’t quite match the overall quality of the Solaris. For people looking for a warmer or more emotional delivery in the midrange, the Solaris is an easy recommendation here.
Treble is quite different between the two IEMs, with the Fusion using a magnetostatic driver to produce the upper frequency ranges rather than a more traditional balanced armature setup. As a result, the Fusion carries a significantly brighter top end than the Solaris, using the unusual driver tech to provide highs that are crystalline and full of energy and bite, but at the same time not harsh. It’s a tuning that’s unlike any other in-ear setup I’ve heard (even the new estat models).
In comparison, the Solaris highs are slightly more substantial but more laid back. They sound smoother and less aggressive with cymbal crashes and other percussion, and provide a greater sense of airiness compared to the more aggressive and vivid Fusion presentation. Quality wise it’s a draw, with both setups being fairly evenly matched in terms of resolution and clarity.
If you like your highs bright, sharp and plentiful, the Fusion will be the suggestion here. If you prefer a top end that is still sparkly but a little softer and smoother, the Solaris wins out. The 2020 is also by far the more forgiving of the two IEMs for badly mastered or hot recordings as a direct result, which is something to bear in mind if your music collection consists mainly of recordings of glass being broken in a chalkboard nailfile testing facility.
With regards to technicalities, the imaging on the Fusion is top tier, and easily keeps pace with the Solaris. Separation in the lows and highs is slightly better on the Fusion, but the midrange feels sightly more cluttered in direct comparison to the Campfire model. Resolution overall is taken by the Solaris, with the additional clarity in the midrange and a slightly tighter presentation in the bass sealing the deal there.
Packaging and accessories are a tie, with the Itsfit model coming with a very nice engraved metal puck carry case, which is far sturdier but less practical/pocket friendly than the Solaris cork case. Both IEMs come with very good stock cables, but the Solaris just edges ahead with choice of tips.
These are two fairly well matched IEMs – the Fusion is a brighter and more aggressive sounding monitor, but still manages to compete fairly well with the more expensive Campfire flagship in a lot of areas. I love the sound of the Fusion, but I think the Solaris is the better IEM overall, pulling ahead in a few key areas and presenting a more balanced and musically enthralling sound to the listener.

Campfire Audio Solaris (original) – (Hybrid – 1xDD, 3xBA) – c. $1099
If you seriously need a comparison between these two IEMs after reading the previous few thousand words then I need to change hobbies. For those who can’t be bothered to read the rest of the review and are just looking for the TL;DR, here it is: the 2020 has more midbass, a slightly meatier midrange and treble that isb’t quite as forward or sparkly as the original. Separation is marginally worse on the 2020, imaging is definitely better. Fit is an order of magnitude more comfortable and just plain easier to keep in the ear on the newer model, and the accessories are pretty much the same but different. Overall, the 2020 is a worthy evolution of the original Solaris sound, and a definite incremental step up in overall sound quality.

Stealth Sonics U9 – (Hybrid – 1xDD, 8xBA) – c. $1099
The U9 is the 2018 flagship from Singapore-based IEM firm Stealthsonics, packing one 10mm dynamic driver and 8 balanced armatures in a 4-crossover design. Much like Campfire Audio, the Singaporean manufacturer utilises various in-house technologies to achieve their house sound, with the team at Stealthsonics concentrating on airflow modelling to achieve the distinctive sound of their gear.
The U9 packs slightly more drivers into the shell, using 2 armatures for the midrange, two for highs and a quad-driver array for “super highs”. The DD is the same size, but utilises a more standard design than the ADLC diaphragm used in the Campfire model. In terms of overall sound, the U9 is an impressive performer in its price bracket, with a crisply detailed sound and razor-sharp instrument placement. Despite its hybrid design, the U9 isn’t particularly bass-heavy, with the DD being tuned to produce less overall quantity than the Solaris 2020. It does have a decent impact in the sub-bass regions, placing emphasis on speed and impact over sheer volume. It feels less full and rounded than the 2020, following an almost flat or neutral response – extension is similar on both models, digging deep into the recesses of sub-bass without any noticeable roll-off. In terms of layering and detail retrieval, the U9 driver is no slouch, but it doesn’t quite match the CA model for overall texture and fine detail. Neither model will be suited for extreme bass heads, but the Solaris is definitely the more bountiful of the two in the low end.
Mids are thinner and more distant on the U9, with it painting a slightly less intimate picture in terms of both stage position for the vocals and overall note size. The U9 feels cooler and leaner in tone, with more emphasis on the edge of notes and a sharper and more overtly detailed response. Resolution is one area where the U9 is noticeably more emphasised, the more neutral tuning allowing the thinner notes to eke out high levels of micro-detail with well recorded music, in comparison to the more laid-back and natural sound of the Solaris. This does come at the cost of a little of the Solaris’ organic timbre and tone, with the U9 sounding more “processed” in direct comparison. The colder tone also provides a more analytical feel to the presentation. In terms of actual resolving power, I would say the IEMs are tied, with the thicker presentation of the midrange on the campfire flagship presenting an equal amount of detail, just in a slightly less obvious manner.
Treble is sharper and more emphasised on the U9, again feeling a little thinner than the Solaris in both both tone and overall weight. The 6 drivers responsible for the higher frequencies provide a superbly linear extension up past the limits of usual human hearing, allowing the U9 to paint an extremely detailed picture in the high ranges without any issues. Despite the extension, the tuning is devoid of any peaks or hotspots, so the U9 is always smooth, being slightly more forgiving on hotter or more poorly mastered tracks in this respect. Stage dimensions feel similar on both, with the Solaris providing the bigger picture and the U9 taking a more widescreen approach.
In terms of driving ability, the Solaris 2020 is the easier IEM to drive, with the U9 requiring a little more power to get to the same listening volume on my usual gear. The 2020 addresses the slight signature variance with different OI sources that was noticeable when comparing the older version to the U9 on different gear, but still hisses ever so slightly more than the U9 in direct comparison.
Build is very different on both, with the U9 being made of a super-light rubberised polycarbonate type material in comparison to the all-metal design of the Campfire model. The Campfire model feels a whole level up in both durability and overall aesthetics here, providing a much sturdier feel and a far more compact and comfortable design. Fit and ergonomics definitely go to the updated Solaris; the U9 use a rounded shell design reminiscent of the Noble Audio universal shell designs, but for me this translates to a very shallow fit and some difficulty getting a solid seal in the ear with most tips. Once sealed, they are Uber-comfortable, but there is definitely more fiddling required to get (and maintain) a seal with the U9 in comparison to the (much) more ergonomic Solaris.
In terms of the overall package, Stealthsonics provide a decent if not mind blowing loadout compared to CA, with a larger (but lower quality) carry case, a variety of tips and two IEM cables from Singaporean manufacturer Null Audio as standard, one with mic and one without. Both cables are terminated in standard 3.5mm single-ended format, so the mic is the main distinguishing feature, which is slightly unusual given the “audiophile” market they are obviously shooting for with this model. Cables are a good standard and ergonomically excellent, but not quite up to the full after-market experience of the ALO Smoky SuperLitz in terms of looks.
Overall, the U9 is a well performing hybrid in the $1000+ market, with a strong analytical sound and excellent technicalities. It offers similar imaging prowess to the Solaris, but diverges quite significantly in terms of tuning, erring more towards a cooler and thinner tonality, with less physical dimension to the individual notes (both in terms of weight and overall “roundness”). As a result, while I am impressed with the technical prowess of the Stealthsonics model, the Solaris is the more engaging musically, giving a weightier and more immersive musical ride when you just want to lose yourself in a track. Add that to the more premium feel to the build and packaging, and I would find myself siding with the Campfire model if I had to choose between them.

Stealth Sonics C9 – (Hybrid CIEM – 1xDD, 8xBA) – c. $1499
The C9 is the custom version of the U9 mentioned above, and is being included in this section as it is FAR closer to the Solaris 2020 in terms of both tuning and overall capability than its universal counterpart. Unlike the U9, the C9 has a warmer and more musical leaning tuning, achieved primarily by an increased presence in both the sub and mid bass region. This isn’t unusual for custom in-ears, and the C9 follows the stereotypical CIEM route here.
The increased midbass of the C9 brings it almost on par with the performance of the Solaris 2020, but the Stealth Sonics DD isn’t quite able to keep up with the more technically adept CA driver in terms of resolution and detailing, so the Solaris still edges ahead here. The presentation is a lot more similar, however, with the additional presence in the midbass region warming the stage nicely and adding a more organic tone to the musical reproduction, almost like an old school tube amp. This does come at the cost of some cleanliness in the bass to mid transition for the C9 in comparisons to both the universal model and the 2020, however.
Technically, the C9 is actually less analytical than the universal version, with a thicker presentation and more body to the notes. This brings it more in line with the 2020, but the Solaris just sounds a little crisper through the midrange in comparison.
Likewise with the treble, the C9 is less for and analytical than the U9, so leans a lot more closely towards the Solaris sound. It still retains the technical prowess of the U9, but just in a more analogue-sounding way. I can’t choose between the two IEMs here, as both have an excellent topn end response for my personal tastes.
Overall, the warmer and slightly thicker tone of the C9 makes the two IEMs extremely similar, with the C9 sounding warmer and less crisp when listened to side by side. The C9 is one of the favourite IEMs in my collection, but I think the Solaris 2020 just edges it out for me with a marginally more resolving and fresh take on a very similar tuning.

Final thoughts
For me, the original Solaris is an IEM that has a special place in my collection, possessing a signature that resonates with me on multiple different levels, and is hands down the IEM I have had the strongest emotional connection to music through since I started in this hobby.
It isn’t hyperbole to say that the Solaris 2020 has now replaced its predecessor in my all time favourites list. It produces a sound that keeps all the elements of the original I loved so much and improves them in a few key areas. The tweaks are small, but the effect is appreciable. Like the original, this isn’t an IEM that will be the end game for everyone, but it does operate in that rarified atmosphere of TOTL earphones that have the technical chops to dissect a track but the musicality to stick you right in the heart of the song at the same time.
If you are a fan of the Campfire Audio house sound, or just after a top tier monitor that sits somewhere on the musical / balanced border, the Solaris is an easy recommendation from me.
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