Campfire Audio Fathom

Intro

The CFA Fathom is a 6BA (2 tweeter, 2 midrange, 2 woofer) IEM housed in a black anodized body with rainbow shiny nipple ring things. Like all other CFA IEMS, it features MMCX connectors and comes stock with Time Stream cables in both 3.5mm and 4.4mm terminations. 11.7 Ohms at 1kHz impedance, 94 dB SPL at 1kHz: 6.75 mVrms, claimed.

Caveats

I have not heard every IEM on the planet, nor have I heard stuff like the super-neutral Gaudio Nair, or anything priced like a used car, with product names like "Smelly Aroma" or "SubTropic Thunder" or "OrioLOL-a-docious Trafadilly". And besides, this is SBAF, and we don't know shit about IEMS. I'm also a clown and this is just, like, my opinion, man. A brief note on "neutral": my personal take on perceptual neutral in headphones and IEMs is that it should replicate the frequency response of an anechoically flat-measuring speaker playing in a well treated medium sized room, i.e., slightly overall down sloped response. I don't agree that "neutral" is flat-measuring at the listening position in such case. Also, Harman is not my bag, baby.

Chain

iPhone 15 (iOS 17.5.1) running Roon ARC (mostly 44.1K/16) --> iBasso CB19 + Anker portable USB power brick --> iBasso DC-Elite --> 4.4mm Lavri Cables Master Silver --> CFA Fathom with JVC SpiralDots

Other amps/DAP/Dongles I tried but I did not like as much driving the Fathoms compared to iBasso DC-E: Piety, Vali3, Cayin RU7, Shanling M6U, Pietus Maximus, MJ3.

Music

Gidge: Tundra
Weval: Remember
Kiasmos: II
Roisin Murphy: Hit Parade
Christian Loffler: A Life
Bersarin Quartet: Systeme
Hidden Orchestra: Dawn Chorus
Max Cooper: Seme
Plini: Mirage
Bat for Lashes: The Dream of Delphi

Ergonomics

Fathom's fit and finish is commensurate with the price. CFA has evolved their body shapes over time thanks to some better CAD work, and refined the block-hewn geometries with some appreciated radii. The Fathom is roughly the same shape and size as the Andro, but fits slightly smaller, meaning, the addition of more facets and radii to those facets makes for a more compact fitting IEM. My biggest ergonomic gripe is with the Time Stream SPC cable. The flat ribbon style cable always puts rearward pressure on the Fathoms, trying to twist them out of my ears, and is also quite microphonic. However, of the silver plated copper cables I've heard, the Time Stream is the least disjointed sounding.

Quick impressions

This is simply the most neutral frequency response in an IEM I've heard. Overall presentation of Fathom's frequency response plus technicalities is, in short: Super-Andro. Fathom also has the deepest, most cohesive and immersive IEM headstage I've experienced, with the caveat that IEM headstaging is usually pretty bad in general.

Bass

Fathom's bass is well controlled and extended, and no single frequency or range of frequencies are emphasized. I did a few 20-200Hz sweeps just to confirm and to my ears the Fathom's are just plain flat flat flat. If there's any nit to pick (and it's more a personal preference) I would have preferred a slight subbass boost of 2-3dB below 40Hz. But having played with subs, a mic, and RoomEQ Wizard on my speaker rig and having heard what "flat to 20Hz" sounds like after convolution, Fathom's bass response is close to true "flat to 20Hz". So, from a "reference" perspective, Fathom's got goldilocks' bass: no Budweiser Beer Belly Bass Bloat, no "fake neutral" "studio reference" bass-light tuning; bass is just right in balance with the rest of the FR. A couple of interesting observations:

• The Fathoms exhibit some canal pressure on initial insertion that screws with the bass more than any other IEM/tip combination I've experienced, for whatever reason; relieve the pressure by breaking the seal momentarily, and the bass falls right back into place.
• The Fathoms also emphasize stereo/phase relationships and contrasts in the bass better than I've heard in an IEM, or any headphone, period. For example, on the track "Siren" by Tourist (the effect begins in earnest around 4:45), when there's hard-panned stereo bass at the same time as mono/centered bass, the Fathoms differentiate this effect wonderfully.

Mids

The midrange is perhaps the least remarkable part of the Fathom's frequency response, but that's likely due to absolutely zero sins of commission or omission in the FR, and how well the mids integrate with the bass and treble. Vocals have just the right amount of texture, without grain or any extra chestiness, overhang, or shrillness indicative of pushed/peaky mids. Nothing extra, nothing missing, and the transitions between the BA drivers is seamless, or at least imperceptible to me. Never once does the midrange of the Fathom lose composure during difficult music, either. Individual musical elements remain separate, and tracking multiple vocal harmonies over a melody in complex mixes is effortless. Fathom's mids are vivid without being velvety, or overly rich.

Treble

Pyrates!!! Remember when Andro blew everybody's minds almost 10 years ago with crazy good overall balance, involvement, and immediacy? And how we all just kinda took it for granted that no IEM was going to really nail top end air without f'ing up the rest of the treble, or overall FR balance? Well, like I mentioned in the quick impressions part, Fathom really presents like a super-Andro with that last upper octave energy now more fully resolved. And the rest of the treble from 4k on up is just as cohesive as the mids. Fathom has zero treble fatigue, no peakiness, and the level of spatial information and detail is almost too much, but never do I find myself reaching for the volume knob to soften things. Overall treble presentation with the Fathoms is slightly down sloping, smooth, coherent and well extended.

Technicalities

Resolution and detail: Fathom has no discernable haze, and microdetail is there in spades, while staying fatigue-free for hours-long listening sessions. I think the Fathom's detail and resolution capabilites have more to do with the overall evenness of the complete frequency response range than with any particular driver type or technology, or crossover or whatever. In other words, although I've never really had a major aversion to BA timbre, I'm not detecting any BA wonkiness whatsoever while listening to the Fathoms.

Headstage: The Fathom's headstage is the first thing that jumped out at me on first listen, and it's perhaps the one aspect that's more than just an effect of great tuning. In other words, in most other audio stuff, especially with transducers, you might get great headstage or soundstage, but at the cost of some other portion of the presentation. For example, you might get HD800 spectacular spaciousness, but with it comes its notoriuous 6k icepick. Or you might get great soundstage and image palpability with some ribbon tweeters or full range magneplanars, but there's always a trade-off in some other area (weak bass, overall treble forwardness, grainy midrange or tizzy treble). However, within the limitations inherent with IEMs, the Fathoms don't have any of those typical tradeoffs. The headstage is the deepest and most layered I've heard in an IEM, and the headstage wraps across and around the head, seamlessly, from behind the ears. I know headstage has always been a bit of the "secret sauce" for certain CFA IEMs, and Fathom more than maintains the hereditary ability. Still makes me wonder what it is exactly that CFA does in the nozzle/tubing/manifold interface with the BA drivers that pulls off the convincing headstage parlor trick...

Macro/Microdynamics: The Fathoms are not whizz-bang super macro/micro dynamic, but they are still highly sensitive, so nothing sounds flat or compressed, either. So, similarly to the midrange frequency impressions, so too are dynamics of Fathom somewhat unremarkable. Fathom's dynamic envelope is satisfactory, and blackground is fine once you find a suitable amp pairing with no hiss or noise.



Comparisons

OG Andro (2019)

Andro presents a bit more intimately, closer-in spatially; Fathom presents more spaciously. Andro lacks the sub-40Hz extension and grip/control that Fathom has. Up at the tippy-tippy top, the Andro sounds a touch rolled off. Inner detail and microdynamics are very similar between the two through the mids, tho Andro lacks the upper treble planktons and large headstage compared to Fathom. Andro is a bit more 3-blobby and less cohesive. In comparison, Andro also lacks upper midrange macrodynamics/exuberance/excitement, and sounds a bit couped up or restrained.

OG Solaris (pre-2020)
(with AZLA SednaEarfit XELASTEC tips because these just work better ergonomically for me with Solaris)

Solaris sounds a bit v-shaped in comparison to Fathom. Bass is slightly thuddy compared to Fathom, sounding like it was voiced more for Transformers movie effects and less for solo piano work. Solaris' slight depression in the mids sounds a touch too "hifi" compared to Fathom. Not quite as spacious, but closer to Fathom than Andro is, headstage-wise. A bit crunchier with attacks than Fathom, especially in the upper mids (again, slightly "hifi").

Timeless 7Hertz

7Hz sounds upper mids- and 40-80Hz pushed, wonky w-shaped compared to Fathom. 7Hz has distinctly less air and upper treble detail, but does still seem to have a treble peak around (maybe?) 6-7kHz despite using foam tips. 7Hz overall presentation is plasticky, smoothed over, bass forward, and less dynamic compared to Fathom.

Conclusions

I've had Fathom for about 3 months now and I went back and forth with myself over whether I should write this review. I'm usually hesitant to write overly glowing reviews like this because it comes off as either "everything is wonderful!! nothing sucks!!" or that in general SBAF just shills CFA stuff as a matter of course. It's usually easier for me to crap on weird sounding or overpriced stuff and write about it. A couple other members here helped convince me to go ahead and write up this review.

As far as the usual questions folks may ask after a good review of some piece of gear: no, I'm not going to sell off my other IEMs. Fathoms are not my "desert island" anything. No, I'm not going to tell everybody to go out and buy 3 pairs of Fathoms for use while eating, pooing, and sleeping. What I will say is that I'm very appreciative of CFA for embracing a tuning that fits my preference for "neutral" and this gives me a very well defined point from which to help triangulate other tunings.

 

Thanks for the great impressions. Did you happen to notice if the Fathom is as susceptible to changes in sound from devices with different output impedances? I'm thinking here of the Andros that got darker as the OI approached zero.

 

I'd have to do some digging on the OI of everything I plugged the Fathoms into and write up some more specific impressions, but I do get the feeling they are susceptible to it.

EDIT:
So a cursory look at reported OI:

Piety: <0.6Ω
Pietus Maximus: 1.5Ω
Vali3: 0.5Ω (low gain, which is what I used w/Fathom)
MJ3: <0.25Ω (balanced out, which is what I used w/Fathom)
Ru7: 0.5Ω
iBasso DC-E: <0.2Ω
M6U: <1Ω

So nothing greater than 1Ω OI that I paired with the Fathoms. I don't have all of that gear in one place right now, both Vali3 and Pietus Maximus are currently loaned out to a neighbor, but I can spend some time later this week putting together some comparisons between Mj3, RU7, M6U, Vali (OG, 6.5Ω OI), and Vali2+ (0.4Ω OI) if folks are interested.

Otherwise, the long and short of it is that I did cycle through everything listed in the original post, and iBasso DC-E had the best synergy with the Fathoms. And not by a slight margin, either. And to reiterate, all comparisons between IEMs in the original post were being fed by the DC-E.

 

hello,
any sort of compare/contrast with the late, lamented, now discontinued ("Sold out.") Ara?
inquiring minds would like to know.
thanks!

 

I can only go on memory as I owned Ara for a week or two (quite a while ago), and that brevity of ownership should probably tell enough about my subjective impressions of them. I found Ara to be too tipped up and brittle in the treble, but that's just me and my tin ears. At the time I also owned Andro and Solaris, too, if that helps trangulate.

 

Regarding the Fathom's likely behaviour with different output Z amps: a reviewer measured FR from a low output (near top of page) and a 20 Ohm output source (~2/3 down).

Both curves look a bit odd to me, but the differences suggest a broadly similar relationship to the Andromeda (edit: maybe more like the Ara) over much of the range, with higher Z sources relatively increasing the top vs the bottom - but with something else in the low bass, the SPL from the high Z source increasing as frequency decreases below ~100 Hz.

I'd guess the extra driver gives the Fathom's impedance curve a rise in the bass vs the Andromeda's low & flat shape there. I'd like to see an actual impedance measurement though.

 

If you have/get a pair, could you measure impedance? Darkstar, too.

 

Overlooked this. One IEM to compare it to is the 7th Acoustics Supernova, which uses the same 6 BA driver setup but with a warmer tilt that sounds effortless.