ETA O2 Loaner Impressions Thread

This was my first time hearing anything from ETA...

Things I noticed:
-) A very polite tuning (and I don't mean that negatively). Not dark, but warm. Not rolled off treble, but tempered.
-) They like power, but not too much. MJ1 was too much here. Sub-bass suffered distortion if you overscale.
-) Band is wide and useful, but also somewhat flimsy as noted above.
-) Pad-rolling might be a cool thing here, but pad-wear might also be a thing I fear.

Things I liked:
-) Bass is good -- really good; and I normally don't like bass-tuned gear in general.
-) Did not feel like it's straining anywhere in the response, except when really, really pushed.
-) Phones and tablets had no issues with performance.
-) Comfort, ears-specifically and overall. I normally shy away from on-ear, but these placed well and didn't shift about.
-) No real fatigue, audibly or physically. Listened for hours with no real issue.

Things I didn't like:
-) Did not synergize well with any of my current tube gear setups. ZDT Jr (Low-Z) was probably the closest to acceptable. Folkvangr with IM was okay, but still... eh, no, sorry.
-) Overall feeling of fragility in the build -- like one bad drop would bring a catastrophic end to the poor thing (I didn't test this, obviously).

Overall, I liked what I heard. These could easily be someone's "relaxing evening" headphones. I'm not sure how mobile I could be with them, but there's good stuff here sound-wise.

Thank you ETA for allowing this to go around, and thank you @ChaChaRealSmooth for managing logistics. I know the loaners have their own drama sometimes, but I continue to really enjoy being part of them.

 

this is exactly how I use mine. I don’t really have the desire/space for a bedside rig, so I listen to them from my iPhone.

 

I wouldn't worry too much about durability for 2 reasons:
1) The materials are very robust (carbon-reinforced polycarbonate + carbon-reinforced TPU IIRC), the headband, while flimsy-looking, is also surprisingly durable.
2) You will get very good service from ETA if need be.

 

Completely fair rebuttal. I perhaps am too used to heavier materials (for good and ill) and as such unfairly underestimate durability based on weight alone.

Thanks for keeping me honest (seriously, no snark).

 

It wasn’t a callout since I think it’s a fair concern, it’s not immediately obvious that the plastics used in the cups are way ahead than the usual ABS used in injection-molded parts, could be useful knowledge for other folks partaking in the tour.

 

ETA O2 Review (Part 1)

Ok, in the past 3.5 days, I've been captivated by the O2 headphones, and my experience compels me to approach this review differently. Instead of delving into the sound quality right away, I want to shed light on the acoustic design choices that I think make the O2 stand out to me.

Aesthetically, the O2 outshines any previous offerings from ETA, boasting a unique and stylish design. While the headband mirrors that of previous Minis (which isn't my personal favorite), the cups are elegantly proportioned, with the smaller pads than the Mini SC/C. The asymmetrically designed E+ pads lend an avant-garde touch, and the openness of the structure offers a clear view of the drivers through the grills. Remarkably, these aesthetic choices also have acoustic implications that I'll delve into later.

During my assessment, I tested the O2 with various setups including the iPad M1 Pro+Dongle, M500.3+HO200, and Spring3+Bliss. While the difference across these setups was subtle, superior systems did enhance the O2's performance in intriguing ways.

Disclaimer: I have no affiliation with O2's development or insight into ETA's acoustic strategies. The opinions expressed here are solely based on my observations/conjectures.

O2's design is noteworthy. To me, it seems like Ev's response to the Raal SR1a and modern Grados. At its core, the O2 is an on-ear headphone. Its design ensures minimized reflection, allowing for a purer direct sound (by theory), which likely offers heightened clarity/resolution. By bypassing concha resonance and interactions, it achieves clearer audio. However, as proven by Grado models, this design might sacrifice some spatiality and authenticity.

O2 addressed this problem with multiple other design choices. I believe one of them is the E+ pads. These pads keep the drivers farther from the ears. The mechanism itself is not too different from some Grado cushions (G or L). However, I found that the E+ pads were very well-calculated, mixing proper outer ear interactions. The E+ pads, combined with gentle clamps, also break the seal, which creates a great harmony with the next components, the surrounds.

O2's spatiality also comes from how the drivers are mounted in the enclosure. Closely observing the internals, it is easy to see that the drivers are not directly attached to the enclosure/baffle, but surrounded by a supposedly very flexible material. This is not unheard of. It is called by various names, including "free edge". I think the surrounding reminds me of my prior inspection of the P5 (Bowers and Wilkins).

Last but not least, the O2 is very open, not only on the backs but also on the sides. I would be surprised if the O2's acoustic impedance is not extremely low. While this choice harms isolation against environmental noise, I am sure that the O2 maximizes the physical airflow around the drivers and ears. I feel the airflow more vividly with the O2s than with any other conventional headphones. Please do not confuse this headphone-generated air with recorded air, which is often associated with the 10+ kHz frequency range. I believe that both are associated with perceived airiness, but they are clearly separated/independent from each other.

So, how does the O2 sound? Simply put, it is familiar yet unique. First, the O2 sounds familiar to me because the tonal balance is quite similar to the Mini open OG that I reviewed previously. Perhaps it has a slightly better bass extension (I'm guessing ETA's new drivers have a lower resonance frequency). If I recall correctly, many of the tonal components are not very different: bass roll-off in the lowest notes (unlike ETA Mini circumaural models), mid-high bass hump, gradual V-tonality centering around the midrange, a little recessed/limited brilliance, nice top-end extension, etc.

Nonetheless, the aforementioned factors (E+ pads, free edge, open structure) combine to create a sonic experience that strongly reminds me of the Raal SR1a, Sony MA900, and Sony PFR-V1, nearly hanging sounding sources in the free space. It is closer to Sonys. While the O2's speaker-like presentation is not as complete as the aforementioned products, it extends much further into the lows and retains some of the good traits of conventional headphones.

There are some limitations found during the evaluation, which I believe are mostly structural. Compared to conventional (high-end) headphones, I always find that (2ch) speakers are limited in resolving ultimate nuance to my ears. There is a certain low-level point beyond which things lose linearity, which is associated with a decrease in crispiness. The Raal had the same issue to a lesser extent. And the O2 has it too, to a certain extent. I believe this is attributable to excursion. For various reasons, speakers that hang in the open space must move farther to push more air to achieve the same loudness. This longer excursion results in lower linearity. As a result, I often hear the O2 mildly smear low-level nuances, which I did not hear with the Mini-S/C in this way.

Another limitation I would point out is that its speaker-like experience is not as dramatic as the SR1a or K1000, particularly in terms of soundstage size, mainly because O2 inherently takes large proportion of outer ear effects out. The spatial presentation is very natural, but the soundstage always feels smaller. In addition, while the instruments are well-separated, the spatial cue locations sometimes seem a little less convincing to me. For these reasons, I found myself frequently favoring small jazz and vocals over orchestral pieces with the O2.

In wrapping up, the O2 headphones from ETA present a noteworthy attempt at blending innovative-ish design with acoustic functionality. Their distinctive appearance is good to my eyes, but it's the acoustic choices that truly pique my interest. From careful design of pads, driver mounts, and cups, the O2 manages to carve a niche for itself. It is, of course, not perfect as discussed above, making them more suited for certain genres/flavors. I really like O2 to the point I want to own a pair for myself. Began debating myself. We’ll see. Hmmmm….

Anyway, well done, Ev and Tommy!

I’m planning to take measurements this weekend. Will follow up with the results and analytic comments. Hope I won't be too lazy..

PS. more pics below.

 

ETA O2 Review (Part 2)

Ok, I spent some time measuring O2 today. Let me go through my findings.



Firstly, we consider the frequency response. At first glance, the O2's curve appears to deviate significantly from my ideal tonality, especially in the upper midrange regions. However, before drawing hasty conclusions, it's essential for readers to understand several nuances about these results.

1. The O2 is supra-aural. Hence, when plotting compensation curves, adjustments for concha gains are necessary. Determining the precise amount of concha gain for supra-aural types remains a challenge.
2. My definition of ideal tonality is based on the weighted average of tonally balanced circumaural headphones.

With that in mind, it's important to note that the orange curve may over-represent the 2-6 kHz region. That said, I won't deny that the O2 seems to lean towards an upper-midrange forwardness, as I did perceive a slightly enhanced energy in that range.

Additionally, the gradual bass attenuation at 50Hz and below is impressively low for supra-aural headphones. For instance, all Grado models exhibit sharper bass roll-offs at 90Hz and lower. The O2 performs even better than many open-back circumaural headphones in this regard.

When comparing the O2 to earlier ETA products, the tonal character of the O2 closely resembles the Mini Open, as I anticipated from my subjective assessment. However, the O2 offers deeper bass and arguably smoother upper mids and treble.




PS. Graphs were updated with the latest results on 2023-09-30.

 

ETA O2 Review (Part 3)

This section serves as an addendum. I'd like to expand upon and refine the subjective impressions from my previous posts.

The O2 is largely experientially neutral. Although I detect a slight nuance in the upper treble's energy, it isn't significant enough to be bothersome. The sub-bass feels somewhat compromised, but on most tracks, the O2 seems to lean towards being bass-heavy, perhaps due to pronounced bass notes.

It's worth emphasizing how airy the O2 sounds, especially its immediacy and responsiveness during complex musical passages. It's arguably the most impressive among the moving-coil dynamic headphones I've encountered. This quality is further enhanced by its smooth yet crisp highs, though they can occasionally feel slightly recessed.

In a previous post, I suggested that the O2 struggled to resolve subtle details. However, after several days of listening, I realized that it handles quiet passages well enough. My later observations indicated that louder passages might sound somewhat simplified in terms of microdynamics. Delving into this further, I think there's a hint of compression in the macrodynamics as well.

The soundstage remains a standout feature. While the O2 doesn't excel in producing sharply defined images or expansive soundscapes, it renders audio in a highly natural and convincing manner. In my opinion, the O2 outperforms Sony's prior models like the MA900, F1, and PFR-V1 in this aspect. This quality alone places the O2 in competition with many conventional headphones.

I also experimented with genuine binaural recordings (as opposed to those generated by binauralizers). The results were astounding; the O2's performance was exceptionally good. I've often been skeptical of 3D sound representation of binaural works in not only traditional headphones but also in floating-style ear speakers. However, the O2 surpassed my expectations. Every spatial component, from positioning and distance to stage depth and ambient distribution, matched the authenticity of many 2-channel speakers. I suspect this is an accidental advantage, especially given the limited availability of binaural recordings. But it's indeed a remarkable discovery.

In conclusion, here's my final take on the O2: If any O2 owners are reading my review and contemplating selling their unit for financial reasons, I urge you to send me a pm!

PS. I ended up buying a pair. This proves how legitimate/honest my review was! Lol.

 

Below is not exactly a loaner impression as it's done with my pair. But I think this thread is the most appropriate place to post..

---

Few days ago, I had the opportunity to compare the O2 directly with the SR1b and MySphere 3.2 (MS3). This was particularly insightful, as the O2, in my view, offers an experience quite similar to floating-style headphones. Here are my observations:

1. The SR1b and MS3 closely matched each other in delivering a vast soundstage. While the O2 wasn't far off, there was a noticeable difference. The SR1b slightly outperformed the MS3 in this regard.
2. The SR1b produced its distinctive ribbon sound, but I was taken aback by how the MS3 led in top-end extensions (typically associated with the 10-20 kHz band), showcasing notably brighter and more shimmering highs. It's worth noting that I'm not referring to the sub-10k treble band here.
3. All three headphones adeptly handled natural airflow, which wasn't surprising given their designs. The SR1b had a slight advantage, followed closely by the MS3. The O2 trailed somewhat, offering a more compact sonic experience in comparison.
4. When it came to bass extension, the MS3 was the most restrained, reminiscent of the K1000 from my memory. The SR1b had a bit more depth, but the O2 eclipsed both with its profound and hefty bass.
5. Additionally, the O2 excelled in bass quality, exhibiting traits like delicacy, elegance, clarity, definition, and texture. The SR1b was not far behind, but the MS3 seemed to lag in this area.
6. For capturing minute nuances in sound (both in terms of frequency shifts and amplitude variations), the SR1b stood out. The MS3 was close behind and on par with the O2.
7. The O2 was the standout in delivering a cohesive and harmonious sound across all frequencies, albeit with a slight V-shaped tonal balance (good for me). There were moments of vulnerability in its upper treble, but its best adaptability of the bunch to various genres resonated with my preferences.
8. The MS3 and SR1b were similar in tonal balance. Between them, I preferred the SR1b as the MS3 felt a tad subdued in the lower treble, causing it to lack some sparkle. The SR1b, on the other hand, slightly overemphasized the upper registers but remained a versatile choice. Both these headphones placed more emphasis on the upper mids than I typically prefer.

For context, all headphones were paired with the Holo Spring 3 and Bliss. I also adjusted the SR1b and MS3 angles for optimal bass, minimizing the ear-to-driver distance.

In summary, each model has its merits. The SR1b stands out for its immersive, stereo-like quality. I'm especially fond of its new transformer box, which pairs seamlessly with conventional headphone amplifiers, enhancing compatibility with other collections of many headphone enthusiasts. The MySphere 3.2 impressed with its streamlined design, ease of use/management, and performance nearly on par with the SR1b. Kudos to LB Acoustic for refining the rough edges that I recall from the K1000. Lastly, the O2 was competitive enough, holding its own against these titans. It's noteworthy that both Raal and LB produce their drivers, allowing for more freedom in manipulating/developing dedicated drivers — something I believe ETA might not benefit from at the same level.

What's next? Well, I'm currently exploring opportunities to compare the O2 with the latest generation of higher Grados, expecting to gain another interesting insights. I'll provide an update once I've had the chance to do so.

 

O2 is a beast. I live a mid-fi life and loved the sound. The fact that you can discuss it in relation to RAAL and MySphere speaks to how much @E_Schaaf and @tommytakis have achieved.

 

I have read that the bass is outstanding, which is great. But when it comes to mids, opinions seem to vary. They certainly don't seem to be forward. Are they just present? Are they recessed? Do male and female voices excel? Has anybody hear any horns on them?

The reviews seem very technical, but vague to my little brain.
How would users describe the mids and treble with rock, classic rock or jazz? I have gotten bits and pieces, but I need more to hit that buy button.

I have had them in the cart twice and chickened out both times.

Thanks!

 

I believe that slightly recessed mids and upper mids are crucial for achieving an overall balanced sound. Our ears tend to be more sensitive to the midrange than to bass or treble. When there's too much emphasis on vocal clarity, the nuances of instruments can sometimes be overshadowed.

Regarding the O2, its mids lean slightly more forward than I prefer, yet it remains well-balanced. There's a subtle emphasis on vocal presence. Both male and female vocals exhibit strong fundamentals. However, the depth of female vocals seems to be slightly restrained in comparison.

For horns, such as trumpets and French horns, the O2 delivers a pleasurable listening experience. The sound is clear with minimal muddiness. While it might lean towards a slightly thin sound, there's no hint of boominess. The presence is commendable, although it might be a touch lacking in sparkle or brilliance.

All above is definitely based on my preference though.

 

ETA 02 Loaner Impressions

I’d like to thank ETA Headphones for kindly lending us a pair of their 02 headphones and the SBAF staff for running the loaner tour.

I’m very sorry, these impressions won’t be as thorough as I usually try make them because I didn’t get much of a chance to listen to them properly – we were in the middle of moving house when I had them. What I can say is that these are outstandingly good headphones and deserve to get much more attention than they have. More people should sign up for the loaner tour.


Comfort and Build Quality
I don’t usually get along with on-ear headphones. I very much liked the sound of the Mini S but the comfort proved to be a dealbreaker. This isn’t the case at all with the 02: they’re much lighter and they rest gently and without putting any pressure on the ear. They’re much more like my long-departed Sennheiser PX100 in terms of comfort. You barely notice you’re wearing them.

Build quality is excellent. They feel strong. The pads might be fragile, at least insofar as they’re made of thin and light material but they're cheap to replace. The cables are great; I particularly like the lightweight, soft, and supple stock 3.5mm one.


Chain
I used three setups with the 02:

• The headphone jack of my MacBook Air (M1 version)
• The same MacBook Air with the iFi Go Bar dongle (single ended)
• Yggdrasil A2 -> Raal Requisite HSA 1b amp (balanced XLR out)

The 02 sounded great straight out of the MacBook Air. They’re easy to drive. The iFi dongle improves the resolution, dynamics (micro and macro), offers more refinement to the tuning, and makes the 02 sound more engaging and energetic.

The 02 also scale very well. The HSA 1b is for my Raal SR1a and LCD-4, but in the absence of any other desktop amps, I gave the 02 a whirl from it. I wouldn’t recommend the pairing. It’s a bit too warm and a bit fuzzy, the 02 losing some of its pristine clarity. (And, besides, the amp makes no sense for the 02 unless you have the Raal headphones; its extra oomph makes no difference to the 02’s sensitive drivers). In any case, with this amp and the Yggdrasil, it was immediately apparent that the 02 can translate the additional resolution and other qualities of a fancier source chain.


Listening Impressions
The 02’s sound is lovely. Its main qualities are a clean, clear presentation, an impressive amount of openness and airiness to the staging, as well as exceptional expansiveness to the headstage, and an immediately enjoyable, lively, and engaging sound.

The transient attacks are snappy and clean. They remind me of my old Focal Clear in this and other respects (at least from memory). There’s a pleasing incisiveness to the sound. The 02’s transients aren’t too aggressive or hard-edged, and they’re less so than the Clear's. I very much enjoyed listening to acoustic guitars and found percussion instruments, like snare hits, to be convincingly crisp and clean.

The treble is nicely extended and quite sweet and smooth. It doesn’t have the slightly crystalline quality of the Clear, which came to bother me over time. I hear no annoying peaks or unevenness. The treble’s not rolled off or overly smooth or soft – again, the pretty fast transients and the clarity may give the treble a sense of precision that’s appealing.

By clarity I mean these aren’t particularly colored headphones. There’s no veil or muffle or haze. There’s no sense of them being over-damped (quite the opposite). Nor are these thick or wet headphones; they have a lightness to their presentation, and there isn’t a great deal of tonal weight. Still, instruments have plenty of substance and heft to them, and the timbre of acoustic instruments is very good.

In terms of a clarity-to-colored spectrum, the 02 would sit (very) roughly here, among my current and [previous] headphones:

SR1a <-- [CA-1a] <--------- [Utopia] <--- 02 <------ [Clear] <------- HD 600 <------[Ether 2] <------- LCD-R <---- LCD-4


The 02 have a bit of a mid-bass punch, but otherwise I’d call them pretty neutral headphones. If anything, they may be a touch mid-forward. I’d need more time to say for certain. And I’d need to AB them with Clear but, again, from distant memory, the tuning of the 02 reminds me of the Clear’s (the latter probably has a bit more bass emphasis).

The 02’s mids are slightly forward. These aren’t laidback headphones, nor are they best suited for slippers and lounging around and being wafted by palm fronds. Rather, they’re fun and lively like a memorable day out at an amusement park. Even when tired in the evening, I found myself listening attentively – and perfectly happily – to music. Vocals, male or female, aren’t especially important to me but the 02 presented them in a nicely prominent way. I’m sensitive to too much energy in the upper mids and lower treble, and the 02 suited my preferences perfectly well here. I didn’t find them to be in the least bit bright or fatiguing.

The bass is great. It’s tight and precise but with enough texture to make double basses sound pleasant and pretty realistic, which is impressive given the small size of the drivers and the on-ear form factor. There’s no real sub-bass, unsurprisingly. But the punchy mid-bass and the good pitch differentiation make the 02’s bass satisfying.

The headstage is an outstanding quality. It’s quite expansive, almost reminiscent of the HD 800 in offering a great deal of lateral space, but without being quite so exaggerated or warped as the Senns. There might be a bit of a diffuse quality to the staging’s spacious width. Instrument separation is excellent, as is the sense of air and space around instruments. These are among the least congested of headphones I’ve ever heard. Imaging is decent, as is layering. The stage depth is decent, too; I had none of that uncomfortable sense of the staging beyond too up-front.

I suppose some people may find them a bit lacking in macrodynamic strength and bass slam, which comes with the on-ear design, I should think. The 02 are plenty percussive and impactful, though, and with the bass punch and the snappy transients, they make for an exciting and pleasant listening experience.

The 02 are also very resolving, and punch well above their price when it comes to presenting the subtleties and details in music.


Conclusion
Along the lines of price to performance, I’d say from memory that at ca. 2/3 of the price of the Clear today ($600 vs $900), the 02’s value proposition make it well worth considering as a cheaper alternative, and as a pair of headphones that get you a good deal of the way to the Clear. The 02 lack the heft, slam, bass strength and depth, and tonal weight of the Clear, as well as the laser-like precise imaging. The Clear have a fuller, more robust sound. But the 02 nevertheless come impressively close to the Focals, if memory serves, and they’re leaps and bounds ahead of the Clear when it comes to offering a spacious and airy headstage.

These headphones really do deserve to be heard by many more people. At first I thought they'd be great for tossing in a bag and for traveling. By the end of the loaner tour, I came to think they're well worth having for convenient listening at home. I may well get myself a pair.

 

Thanks for the reply!

 

Thank you to ETA for loaning out these excellent little headphones!

These were better than I expected, to be honest, and I had pretty high expectations from the previous impressions on this thread. My thesis is that these are what high-end Grados should be. They do a lot of things in a similar way, but better.


Gear Used

As others have pointed out, these are quite easy to drive and sounded good out of everything I tried them with. They do scale with better equipment, but it's not dramatic like the Sennheiser HD6*0 series:

* Yggdrasil+ OG -> DSHA-3F
* iFi Zen One Signature -> Piety
* iFi xDSD


Comparison to Grado RS1e

The biggest difference between the O2 and my old RS1e is the tuning—the Grados are an interpretive listening experience (to quote @purr1n) with rolled off bass, slight mid-bass bump, emphasized and peaky upper mids, and laid back treble, while the O2 are much more natural. The O2 have modestly recessed lower mids and slightly emphasized upper mids with a dip in the lower treble. This tuning coupled with their fast transients can make them sound a little bit lean, but the bass presence helps give them extra warmth. They also seem to have some "inner warmth" that I can't put my finger on, but it makes them sound warmer than I would expect based on my other listening notes.


Other good stuff:

• Fast transients that emphasize the attack of notes much more than the decay. This gives them a lively and nimble character. This reminded me of the RS1e that I sold.
• Extremely natural soundstage. I noticed it when I first started listening and then it just disappeared for me because it was so natural I just forgot about it. This also reminded me of my old RS1e, but the O2 sound more natural and slightly less spacious.
• Great macrodynamics. Between the fast transients and strong macrodynamics, these are a very engaging listen.
• Excellent bass. The bass is well extended and has very good punch and body. I feel like the bass has more body and decay than the rest of the spectrum, actually.
• Very good separation. The fast transients, good staging, and modestly recessed lower mids help keep instruments separate in the mix.

Some not-as-good stuff:

• These are very good but not great at microdynamics/plankton, which I'm realizing is very important to me. They pull out a good amount of microdetail, but this is probably where they're the most behind my other TOTL headphones.
• They sound a little unrefined sometimes—there's a bit of a ragged character to them at times on the leading edge of tones. This is most similar to the biodyna ZMFs, but with a different character. The biodyna ZMFs have a raggedness that sounds more natural and contributes to their timbre, while the O2 just sound slightly distorted to me.
• I noticed that electric guitars had less bite than I was expecting given all of the O2s characteristics. I'm not sure, but maybe this has something to do with the dip in the lower treble.

Conclusion

Overall, these are truly excellent headphones, especially when you consider the price. They surprised me with how good they are. I don't think I'll buy them because I they don't fit into my collection at the moment, but we'll see what the future holds

Bravo ETA!

 

I want to thank ETA for the loaner and wanted to leave my thoughts and opinions with a couple caveats.

I haven’t heard ETA Mini O or S.
I was on the Mini C Tour and posted my thoughts here.

I previously owned Genesis G: both versions (300 ohm and 32 ohm driver). AFAIK, the same 32 ohm graphene driver is in the O2. I still own and enjoy the Genesis P but I think there is only one other person who has a pair.

The other main thing to know is that I’m not a fan of on-ear headphones due to having my ears smashed by the pads and I have sensitive pinnae lol. I found the headband to not be comfortable on the Mini C loaner but this time the same style of band on the O2 was totally fine. It appeared as if they were strategically bent to help with ergonomics.

All listening was done using my iPhone with the Apple lighting dongle and Roon & Apple Music. I feel that the ability to get good sound off of lowly sources is a big plus and also a problem for us audio nerds. A lot of people here justifiably feel that if a headphone doesn’t scale with better gear that it is cursed. I didn’t even bother because I am not interested in replacing my regular headphones and gear. I’m looking for something portable that potentially sounds better than Airpod Pros and Gen P.

I started out using the E+ pad but no matter how I spun it around I couldn’t get them comfortable, but I listened long enough to get a good feel for them. I switched to the F-Cush pads and made sure they were on correctly and left them on the whole time I had the loaner.

I still really like the Gen P and you can also read my impressions here. This will give you some context because I found the O2 and GenP to sound very similar. So similar that I don’t have a need to buy O2. However, the O2 are more portable and some may prefer the on-ear design. I feel like GenP was my favorite ETA design but now that is the O2 because you can actually order a pair.

I am going to cut and paste from my MiniC review because I feel the same about O2:

I wouldn’t go as far as some to compare to my $$$ headphones. They don’t have stupendous bass, they don’t have crazy soundstaging like RAAL but they are only $600 which isn’t cheap but also not outrageous.

I think ETA has consistently made excellent, good value headphones. Ev is a genius when it comes to tuning. Please don’t hate me, but I do think the 3DP of the shells is not good enough anymore to match the tuning. I hope that they can step up their aesthetic game to match what is going on under the hood. To me, ETA headphones are like a Dodge Challenger or Charger. Awesome engines and killer tuning but in a cheaper looking package.

I always say this, but I can’t wait to see what ETA is going to come up with next. I hope it is a big boi headphone that can scale up (fingers crossed).

 

O2 vs. SR80e

During the past few days, I revisited my SR80e (that collected dust inside my treasury box lol). And I had fun by comparing it to the O2 side by side. In terms of sonic quality and refinement, the O2 clearly shines. Given the considerable difference in their recommended retail prices (with the O2 being about five-ish times pricier!), this was already expected.

That said, what truly surprised me was how closely they mirrored each other in sound, more so than I had anticipated. They share a lot in delivering a sense of realism and spatiality. It's also worth mentioning that I'm using Geekria flat pads with small holes, which seem to tame the tonality quite substantially—definitely more than the stock cushion.

Setting aside the disparity in quality, the SR80e offers a slightly tighter bass, leaner mids, and a more pronounced presence in bass instruments. The guitars feel more immediate, the cymbals have a distinct sizzle, and the saxophone possesses a notable bite.

On the other hand, the O2 delivers richer low frequencies, crisper upper mids, and adds a punch to the kick drums. The higher octaves in O2 also seem more vibrant, potentially contributing to its broader soundstage, airy feel, better 3D sounding experience.

Both headphones commonly exhibit a very commendable immediacy. However, there's a subtle but audible nuance in the O2; its drivers seem to halt quicker during most sequences.

The comparison has really piqued my interest in the RS2x. I'm eager to see how they (o2 and rs2x) stack up when the quality is on par.

 

Many thanks to Dan ( @ChaChaRealSmooth ), Evan ( @E_Schaaf ) & Tommy ( @tommytakis ) for organizing a loner for ETA's newest release, the “O2”. I imagine anyone reading this would be familiar with ETA by now, but there is lots of excellent information to be found on their website if you're not familiar with them ( https://etaheadphones.com/pages/about-us / https://etaheadphones.com/pages/meet-the-team ). Like the Mini, this is an on ear headphone but the design is wholy new and created to maximize airflow, among other things. However just like the OG Mini, this was designed from the ground up by the minds at ETA. I'll add that like every headphone I've heard from ETA, I think they've done something special here. I'll try to keep it relatively brief but will gladly answer any questions I can.

Currently my audio chain is comprised of various WAV, FLAC & MP3 files played from JRiver on my refurbed HP Elite Desk via USB to a Schiit Bifrost 2 into either my Pro iCAN (1st version) or ZMF Pendant (also 1st version). The O2 is a 32ohm headphone, and the ifi was a wonderful match on low/medium gain. Interestingly where I found the O2 wasn't too sensitive for the Pendant, there was some slight noise detectable with no music playing (a common occurrence with the OG Pendant). Despite that the sound out of the low Z tap was truly engaging. Sadly I didn't discover this till the end of my listening, which is a shame because I really enjoyed the synergy there. I also experimented with various DAPs, all of which could drive the O2 without noticeable degradation. Keep in mind that although these are very efficient headphones that pair well with a quality dongle or phone, they do scale with "better" equipment IME. I have the word better in quotes because I found that it's more of a synergy than scaling up, so "better matched" might be more accurate. Either way I love the fact that I can enjoy these out of modest gear without feeling like I'm missing out. Puttering around the house with the O2 & an old Fiio X5 (2nd gen I think) was a real joy.


Comfort, Aesthetics and Build

Like almost all ETA Headphones I've handled, with the O2 build quality is quite solid if somewhat utilitarian. ETA utilizes 3D printed cups which may not look opulent, but to me they have an attractive vibe. Many are calling for ETA to produce products with more refined aesthetics, but I'm on board with sacraficing some looks in favor of saving a few bucks. They are still using a Sony headband, which I find to be perfectly adequate. An ETA developed and produced headband is confirmed to be in the works and this would likely dispel the last vestiges of DIY that seem to hang around their headphones. Earpads are of the snug over ear variety and posed no comfort issues during my time with them. It seems the aforementioned "E+" pads were installed and all listening was done with them. I found them more comfortable than any Grado-esque pads I've ever tried and I was able to wear them for hours with out discomfort. As previously mentioned, these seem to have been pre-bent into an excellent shape at some point during (or before?) the loaner that minimizes clamp and helps with comfort I think.


Overall Sound

Like every other ETA headphone I've heard, I found the O2 to be a very engaging headphone, probably the closest to a "neutrally tuned" headphone that I've yet heard from ETA. I hear a very balanced tuning from the the O2, with good extension on both ends and a very slight mid-bass accent that play right into my preferences and doesn't intrude into the mids. Definitely some roll off in the sub-bass, but the reach down seems obvious to me and never left me wanting. Full, slightly dry midrange with a little bump somewhere around the 1-5Khz area as well that adds a bit more clarity and bite as it transitions to lower treble (sometimes a touch too much for my tastes), after which everything sounds pretty even to me, elevating incrementally instead of a downslope. Transients are the snappiest I've heard from ETA, staging is Larger than I've experienced with any of their headphones as well. Very good depth, decent width and imaging is slightly indistinct but not bothersome. Detail and nuances are readily apparent and approaching TOTL levels, even if just shy of those last few percentage points.


I'll intersperse my thoughts on sound with impressions with the Mini-S since it's the most comparable headphone I have on hand.

- Bass is fuller with the Mini S, which given the semi-closed nature isn't that surprising. "S" has lower reach to my ears, and a fuller mid-bass as well. O2 is definitely cleaner and tighter, it slams a touch harder as well. A matter of preference really as well as being dependent on the type of music being played.

- Mids are very similar with a bit more lower mid energy from the Mini S and more upper mid energy from the O2. I found O2 upper mids to be a bit too much at times with the Bifrost 2/ifi combo, but much less so with the Pendant. Weather that has to do with the Bifrost or the ifi or the combo itself I'm not sure, but the effect was definitely there. I was pleasantly surprised how much more in tune with my preferences the O2 was when used with the Pendant.

- Treble emphasis is more obviously pronounced with the O2, but I didn't find that aspect to be particularly fatiguing. I think after 2K or so, the O2 has more of an up tilt in frequency, and the "S" has a gentle downward trend. Plankton and detail retrieval would go to the O2, though not by a huge margin.


I found the O2 to have wider & deeper stage than the "S". I've always felt the "S" to be more on the intimate side, but never distracting. When placed next to the O2 the difference is more obvious. Being semi-closed, the "S" does feel more...well, closed in. The O2 is as open & airy as I've ever heard from a headphone. The unique design no doubt plays a big part here.
For my personal tastes, the Mini-S is closer to the sound signature I gravitate towards, but I could definitely be happy building a system around the O2, one that would mitigate the upper mid/lower treble emphasis. One that would likely involve tubes if the Pendant is any indication.

In the end, ETA has done a great job with the O2. At $600 (USD at the time of writing) I'd say the argument could be made for the O2 being a bargain, even if 6 Benjamins is nothing to sneeze at. Personal preference will (always) play a part here of course, but if under 1k is the market you're shopping in I highly recommend checking out the O2.

 

Hello SBAF dudes, I am not often seen about, but I have been in ETA's personal discord and finally bit the bullet to purchase an o2! I would also like to disclaim, I am not a die hard audiophile, i am more into the building aspect rather than sound but here's some impressions!

After listening to it all day, this is a very good headphone for sound quality, probably one of the better ones priced at its current listing. Its a very relaxed tuning that isnt harsh or fatiguing at all in any way, which is helped a lot and complimented by its bass. While being an on ear, the bass quality and quantity is wonderful. Its enjoyable and not bloated to my ears with a good heft to it. Mids are relaxed, with a bit of recession but its not particularly an issue that can ruin the experience for many people. Treble is also something I noticed that doesn't sparkle of cause sibilance, however I can definitely hear it to have a form of extension and not much of a fall off in that regard that really helps the tonality.

Staging is...ok? Its not going to beat an hd800 which is known for its wide sound, and I actually find the o2 to be a bit small sounding in depth. Not a fan of that imo, as with some of the timbre. I've felt there were times some of the instrumental separation was a bit closer than I would like. Some instrumentals didn't have that complete sense of punch that makes it feel satisfying and so, rather just like it is there. While I do enjoy a good punch to my guitars, this doesn't seem to really benefit in that regard and is relaxed. It's smooth, a little bit much at times yet there are also times it is very engaging. Some songs like Invisible by Duran Duran has never sounded so lively and fun! Feels like a new breath of fresh air for me. So while it may lack at times, there are also those magical moments.

Tracks that truly benefit from the o2 is honestly anything, and that is what I love about this. While some tracks can be lacking in a dynamic sense and the feeling I get from the overall sound, there are also times you just want to bop your head and get sucked into the music.

Comfort is up to the person, if you can handle on ears for long periods of time, its going to be really comfortable. However, some people haven't liked the current state of the padding, and I can see why. But, the ETA guys are actually working on that, to make sure they are improved and better which I greatly admire. Build is to be desired to the persons perspective as well. The o2 is certainly priced at a point where you wouldn't often see a premade headband and 3d fdm printing, but in this situation, I actually think the o2 has really clever design choices that justify that price tag! Its so small, robust and light that doesn't make me worried about it breaking any time soon. As a 3d printing enthusiast myself, this really makes me happy to see it being a used technique that standard production methods much like injection moulding and casting couldn't do ever.

It's not perfect in any way, but this headphone scratches an itch I find in headphones lack, which is passion. You do not see many headphone makers with that passion often. Only a few companies exist now that I can honestly say they're doing something new, and trying to make people understand that. As if it's an art form, and consider this a medium I am in love with.

Well done ETA.

 

To say he liked them would be an understatement.