Phil's Superpower of Enthusiasm

[ORIGINAL MSRP $499. Currently available directly from Drop.com for $429 new in January 2026. Purchased used from r/AVExchange for $225 in June 2025.]

[Tl;dr: The Aeon x Closed is a solid closed-back offering in the current market, and my personal choice under $500 if you can’t get your hands on a lightly used or new old stock Focal Elegia. They’re a little bass light, and a little treble heavy, so if you pick up a pair I strongly suggest investing some time with EQ. I’d also love to spend some time with a new pair of these, as based on a couple of things I heard I’m curious if I have a non-standard pair. Oh, the joys of buying used!]

Scores:

Cost-agnostic: 7 out of 10 Denalis

Cost-sensitive: 6 out of 10 Denalis

	Bass1	Mids	Treble	Soundstage	Comfort/Fit2
DCA Aeon X Closed	3C	3B	4B	4B	A/B3

TABLE OF CONTENTS:

1. Introduction
2. Review notes
   1. Testing rig
   2. EQ
      1. EQ Update
   3. Volume
   4. My torture testing list
3. The Basics
4. Sound
5. Amplifier Compatibility
6. Build Quality & Appearance
   1. Connectivity
   2. Construction
   3. Comfort
   4. Appearance
7. Value & Comparisons
   1. Focal Elegia
   2. Focal Azurys
   3. Sennheiser HDB 630
   4. Hifiman Audivina
   5. Capra Ouroboros/Golem Ouroboros
8. Overall

Introduction

Dan Clark Audio (“DCA”), formerly Mr. Speakers, is a great example of a company that started out in the headphone mod market before eventually moving on to creating their own designs, not unlike ZMF. DCA ended up on my radar through its collaborations with Drop.com (formerly Massdrop) as Mr. Speakers and then later under the DCA name. For most of my time in the headfi space, their offerings were much too expensive for me to seriously consider, despite the really excellent reviews a lot of their products received.

This summer, I had the chance to review a couple of really excellent closed backs which brought me around to the idea that maybe closed backs weren’t mostly universally terrible, and I decided it was time to try out one of DCA’s closed back offerings. This pair of Aeon X Closed popped up on r/AVExchange at a pretty reasonable price, and I decided to give them a shot.

[No, I don’t know why it took me so long to get around to reviewing them either.]

Review notes

Testing rig

Here’s my basic testing protocol.

Based on my philosophy on the allocation of resources in headfi, except where otherwise noted I’m going to primarily be testing these with the $299.99 Topping DX5 II⁴ DAC/amp running balanced via a Hart interconnect and connected via USB-C to a M2 Ultra Mac Studio running the Roon client.

EQ

As noted in my Bathys review, I mostly prefer to test headphones with their default tuning, assuming that most people won’t take the time or make the effort necessary to use a third-party EQ. And the Aeon x Closed really don’t need EQ; they sound pretty good to me out of the box, though I have played with EQ a bit over the last seven months.

The Aeon x Closed do, however, come with a set of four filter options for insertion inside the cups to tune the sound: black foam, black felt, white felt with a single notch, and white felt with two notches.⁵ My (used) pair came with the single-notched white felt a little bit discolored, so I have left those alone, but played around with the rest of them before settling on combination of the black foam (closest to the drivers) and the white felt with two notches closest to the ears; it was the closest to my listening preference without going over the top on the treble.

EQ Update

[EQ Update: After a lot of listening and fiddling, and taking Resolve’s advice to try listening to the Aeon x Closed without any of the tuning inserts to avoid blunting the dynamics, I’ve settled on a 10-band parametric EQ adjustment (a mix of Resolve’s, and Unheard Labs’, with some tweaks of my own especially in the bass):

The Aeon x Closed don’t *need* EQ but it fixes a couple of little issues especially when you’re not using any of the tuning inserts, and I’m almost exclusively listening to it these days with this EQ applied.]

Volume

Here are the volume settings I use with the Aeon x Closed (unless otherwise noted, running via Roon with no headroom management, playing Daft Punk’s “Face to Face” from Tidal):

• Chord Mojo: white, light red, light red, red
• Dongles:
  • Apple (iPhone 15, Apple Music): 85%
  • Crinear Protocol Max: 80% (balanced); 90% (single-ended)
  • Moondrop Dawn Pro: 80% (balanced); 90% (single-ended)
• Holoaudio Bliss (KTE): -27 dB (balanced)
• Schiit:
  • Fulla: 11:30
  • Hel2: 11:30
  • Mimir/Jotunheim 2 (Mimir has a -15 dB pregain applied via Forkbeard): low gain, 1:00 (balanced); high gain, 12:00 (single-ended)
  • Modi/Piety: low gain, 11:30
  • Modius/Magnius: low gain, 10:30 (balanced); low gain, 11:00 (single-ended)
• Topping:
  • DX5 II: -27 dB (balanced); -14 dB (single-ended)
  • E30/L30: lowest gain, 11:30

My torture testing list

Apple, Tidal, Spotify.]

The Basics

The DCA Aeon x Closed are a closed-back, planar magnetic headphone designed by Dan Clark Audio and released via Drop.com as an exclusive product. They are, however, very close in design and tuning to the $799 DCA Aeon 2 Closed. They’re a relatively easy to drive pair for a planar, with a nominal impedance of 12.5 Ohms and a sensitivity of 91 dB/mW, and weigh in at a moderate 325 grams.

The Aeon x Closed ships with a pretty rigid case, four pairs of tuning inserts, and a dual-entry DUMMER connection, single-ended, 6.35 mm-terminated cable.

Sound

The soundstage on the Aeon x Closed is pretty good; decently wide (especially for a closed back!) and with excellent instrument/layer separation within that stage. On “Chan Chan” the bass is distinctly out to the left with the rhythm guitar close in space but not overlapping or confusingly close. They have more front-to-back soundstage than a lot of other options, too, with the guitar riff at the beginning of “Love Can Damage Your Health (Laid Mix)” being nicely rotational. Tracking across channels is excellent and crisp as well. The toms pattern in the chorus on “Thunder Lightning” is nicely placed in space, if not as impactful as I might like (see, e.g., the next paragraph).

The dynamics are pretty good. Starting at a comfortable volume on “It’s All So Incredibly Loud” is unpleasant by around 2:30. The microdynamics are good but not great, with the bass bell tones on “Angel (Blur Remix)” missing some of the punch that I would like and even the treble bell tones not quite where I want them to be. The warble after the bass hits is also somewhat lacking. The microdynamics are definitely better without the tuning inserts, but the treble approaches being unbearable without them.

Overall, I certainly enjoy the detail and resolution for casual listening, though they’re not what I would grab for more critical, clinical listening. Despite it being one of the primary complaints about the Aeon, I don’t find myself thinking that anything is missing during a regular listening session, with the caveat that you don’t hear Meshelle Ndgeocello’s fingers coming off the strings on “What Did I Do?” the way you do on something like the Arya Stealth or HE6 se v2. The detail definitely goes up without the tuning inserts.

The bass on the Aeon x Closed is pretty par for the course for a closed back of this kind. It’s not particularly emphasized (and I might add a bit more for regular listening via EQ) but it’s very clear and clean sounding. Bass extension isn’t amazing, but you get most of the notes on “Got ‘Til It’s Gone.” The brain wobble on “Limit To Your Love” is a little disappointing, but generally sub bass isn’t a huge part of my listening so it’s not the end of the world (and it’s reasonably easy to correct with EQ).

The midrange on the Aeon x Closed is good; not overly forward but doesn’t get lost in the mix either. Vocal timbre is generally pretty good as well; voices mostly seem pretty natural. Jill Scott carries through on “Calls” (both the main vocal line and the little runs she’s doing in the background), Amelia Meath’s voice cuts through the synths on “Coffee”, and Sampha’s voice is beautifully reproduced on “(No One Knows Me) Like the Piano.” The guitar solos on “Garcia Counterpoint” are nicely and cleanly separated where they overlap.

The treble is probably the roughest region for me as a listener of the Aeon x Closed. The 2 notch white felt provides some much needed damping, but I find when I hit a particularly treble-y track like “2021” or “Will O’ the Wisp” I find myself reaching for the volume knob without even thinking about it. It’s not harsh the way some of the Hifimans get, but it’s definitely trending that direction and I find myself EQ’ing out some of the treble peaks for casual listening. If I were listening to these a lot, or they were my main closed back option, I would probably look to find another damping material for inserts that would reduce it a bit further without relying on EQ.⁶

It’s also worth noting that while the tuning inserts tame some of the frequency response, that comes at the cost of some precision and detail. Microdynamics are definitely a little better without any of the inserts, though they’re still not particularly strong. I might spend some time working on an EQ profile that will let me listen without the inserts.⁷

Let’s take a quick glance at a graph (compared to my beloved HD 6XX just for reference):

This more or less tracks with my experience. I’m a little surprised by the degree to which the Aeon x Closed is bassier than the 6XX; my perception of bass on the Aeon is that it’s VERY low, to the point where I’m EQ’ing bass into the tuning. The rest of it checks out; you can see the slightly peaky treble that troubles me at moderate to high volumes.

[Editor’s note: The last thing I would note is that while overall the timbre is pretty good, every once in a while I hit a track or section of a track that just sounds wrong. As an example, “I Against I” is weirdly bright and flat via the Aeon x Closed. Part of that may be due to the soundstage; this is NOT an intimate headphone and that track is a pretty intensely centered one. Ditto “Just a Cloud”; there’s a weird … what sounds like interference pattern in the treble? Not a big deal, but worth noting.]

Amplifier Compatibility

The Aeon x Closed aren’t super hard to drive, and I think they’re pretty amp-agnostic. They play well with things from a $9 Apple dongle to a MUCH more expensive Holoaudio Bliss (KTE edition)/Cyan 2 stack, and everything in between. Folks on the internet (and we know they’re never wrong!) seem to believe that the Aeon x Closed benefit from a higher voltage, my experience has been that they sound pretty damned good with just about everything. And I have absolutely no logical explanation for it, but … the treble is less problematic at higher volumes on the Bliss. 🤷‍♂

️At least for me, I don’t hear much difference (if any) with tubes (like the Apos Gremlin) or a tube-flavored solid state (like the Nitsch Piety). Not uncommon for a low-impedance planar.

Build Quality & Appearance

I’m generally pretty pleased with the design, build, comfort, and appearance of the Aeon x Closed. They feel like a well-built, premium product WITHOUT relying on sheer weight to convey that sense.

Connectivity

This is my primary complaint about the Aeon x Closed, and it shouldn’t be as big of a deal as it feels to me; I LOATHE the DUMMER connectors. It’s so dumb. It’s like Apple’s Lightning, but without being the biggest company in the space and therefore able to bully people into adopting it. Like what the actual hell. I don’t want locking cables on devices I carry around attached to my head. I live with an enthusiastic golden retriever who has a long and storied history of accidentally pulling things off tables by getting tangled; I want cables that disconnect before they strain too much, and IF you wanted locking cables there are like a dozen connectors you could have used. I mean, mini-XLRs are also dumb but they’re RIGHT THERE, and already ubiquitous in the high-end headfi industry.

Okay, rant over. Sorry about that.

The Aeon x Closed uses a dual-entry, DUMMER connector. They come with a 6.35 mm-terminated cable. I like running most of my amps balanced (and that’s the only way the Apos Gremlin can be used!), so I bought a Hart Audio interconnect for $63 that I can only use with this one pair of headphones, which is so STUP— … sorry. Woosah. DUMMER is balanced-capable, so after that one purchase I can use the headphones with any of the terminations in my kit.

If you haven’t used DUMMERs before, it’s worth noting that they can only click in in one particular orientation, and you don’t need to hold back the outer connector in order for them to click in; if they don’t press in easily rotate them until they do.

Construction

The Aeon x Closed are light but feel well-built and sturdy. The band is two small metal rods but somehow manages to provide just the right amount of clamp for my head; I appreciate that you can twist them enough to easily access the interiors of the earcups without them feeling floppy when being worn. I do wish the adjustment mechanism on the suspension strap was a little tighter on the rods as I do have to adjust them most of the time when I put the headphone on, but overall it’s very well designed.

The cups are larger than usual and nicely oval-shaped and fit my ears pretty easily, and the outside of the cups are a combination of a nice, smooth (and QUIET!) plastic and carbon fiber inserts. Swivel for the cups is limited as it relies on the rods shifting giving you VERY little free swivel, but probably 30 degrees without applying TOO much force. The cups are connected to the band by a pretty ingenuous arm, but only have 30-40 degrees of tilt.

More than anything else, the build of the Aeon x Closed reminds me of the MUCH more expensive Meze Empyrean II, the highest of compliments for construction.

Comfort

These are among the most comfortable headphones I’ve owned; they are clampy enough to not move on my head even when I’m moving around a lot and to evenly distribute the weight of the headphones between the ears and the suspension strap, loose enough to be VERY comfortable, flexible enough to sit consistently on my head, and light enough overall to be great for long listening sessions. The cups are also plenty big for my ears.

The comfort of these are likely to vary a little bit more than some other headphones based on their limited swivel, tilt, and adjustment, but for me they’re damned close to perfect. I’m tempted to see if I can figure out how to build a headband like this for my next pair of 3D printed headphones.

Appearance

Appearance is, as always, pretty intensely personal and subjective, but I really like the way these look. They’re not as big as some audiophile headphones, and while I’m generally not a fan of carbon fiber (at least not the fake carbon fiber patterning on a lot of cheap products), in this context it … just works.

Value & Comparisons

I’m not going to compare these to the Fiio FT1 here. If you’ve spent any time in r/HeadphoneAdvice you’ve probably seen me say at least a couple of times that the FT1 is the only closed back under $500 that I recommend without reservation … this is the $500 headphone that I’m talking about. The FT1 is a great headphone; this is just better. Period.

Focal Elegia

The Focal Elegia are my favorite closed back, and nothing so far has really been THAT close. They are, however, out of production and unless you know what you’re doing, I caution people looking to buy there first serious pair of headphones on the used market. If you can’t get a good condition Elegia, are these a good substitute?

Yeah, to me they are. They’re definitely a different style of closed back, both in terms of dynamic driver vs. planar magnetic, but also in philosophy, approach to tuning, and dynamics. When I compared them in my Elegia review, I said that I might take the Aeon x Closed over the Elegia without EQ, and the Elegia if I could use EQ. I think that’s still true, if I’m using the tuning inserts on the Aeon. Without them, I’m taking the Elegia every time. The thing about the Elegia (and most Focals) that I love is their dynamic punch, which the Aeon x Closed … lack. I also think that the old-style, larger Focals are some of the most comfortable headphones, but the Aeon x Closed comes pretty close.

Interesting …. I don’t hear that mid-bass hump on the Aeon x Closed at all; to me the Elegia is better and stronger in the bass the whole way through, with better mids and similar treble.

Focal Azurys

Here’s what I said about the Azurys vs. the Aeon x Closed in my Azurys review:

“At $500, you can also get the excellent Drop + Dan Clark Audio Aeon x Closed (review forthcoming), whose comfort and general sound profile I like more than the Azurys.⁶ At MSRP, I’d definitely take the Aeon x over the Azurys for both sound quality and value for most use cases, though the Azurys is easier to drive and I might prefer it for use out of a phone or a similar low-powered device. As far as comfort, the Aeon fits my head and ears slightly better, once I got the suspension strap adjusted. Properly sized, the Aeon disappear on my head while I’m always at least aware of the Azurys.

The used market for both seem to be inconsistent, and the sound quality difference isn’t huge. You’d probably be happy with either if you found them at a decent price.”

A year later, I think that’s still mostly the case. I’ve got the Azurys up for sale just because I haven’t used them since I completed the review, absent a couple of times I’ve used them as part of a review of something else. The Azurys definitely has better bass, to the point of distraction for me, but if that’s what you’re going for the Azurys are going to be a better pick for you.

I can’t find anyone who’s measured both of these headphones, interestingly, and as skeptical as I am of measurements as the be-all, end-all, I’m even more skeptical of mixing and matching measurements between rigs, reviewers, etc.

Sennheiser HDB 630

This is an interesting new wrinkle in my headphone journey: wireless-first products that meaningfully compete with straight up audiophile headphones? Even good ones? Perish the thought!

I have thoughts on Bluetooth that will surprise nobody.⁸ BUT, modern Bluetooth has fixed many (though not all) of the issues with older generations, and manufacturers are both doing clever things with Bluetooth codecs AND designing clever products around Bluetooth connectivity. For the most part, the Bluetooth headphones that I’ve really liked other than the Airpods have been very expensive, and while the HDB 630 aren’t cheap, they’re like, not a LOT more than the Aeon x Closed. Is it worth paying $80 more for the HDB 630 over the Aeon x Closed? In a lot of cases, yeah, I think so.

First, we’ll start with all the things you’re getting for that $80; wireless connectivity, an excellent BTD 700 Bluetooth dongle (providing low-latency, consistent connections) that would otherwise cost you $50, a really excellent app, on-board five-band parametric EQ, and (of course) active noise cancellation vs the (decent) noise isolation of the Aeon x Closed. You are giving up some comfort, the ability to run purely passively, and (arguably) some aesthetics.

Second, let’s talk about sound. Honestly, with or without EQ, I’m taking the HDB 630 for pure sound quality. Even the “neutral” setting is pretty great; nicely bassy without being boomy; solid, present mids; and mostly well-controlled treble, certainly better controlled than the Aeon x Closed without any inserts. I haven’t done my testing or review yet for the HDB 630, but at least so far reports seem to be pretty good about the HDB 630’s DAC mode, wired to a source via USB-C. And then you add in full, on-device, iPhone adjustable parametric EQ and you get a really solid, audiophile-worthy closed back that also happens to be wireless.

So, why would you get the Aeon x Closed over the HDB630 or something similar like the Focal Bathys?

The answer is that most people, probably, shouldn’t. I personally really enjoy using desktop amplifiers and DACs and generally prefer wired headphones for desk-based work, but these are all limitations (and extra costs!) for most people. I haven’t spent a lot of time with it, but I’m going to guess that you can get the HDB630 pretty close to the sound of the Aeon x Closed, too, if you really want to (certainly closer with a full parametric suite via a third-party EQ app, but probably close even with the five-band on the app!).

For me, personally, the Aeon x Closed is both more comfortable and more aesthetically pleasing. I find the current generation Sennheiser wireless offerings pretty bland and generic, and on the edge of being too small in their ear cups. And whether or not they SHOULD, aesthetics do affect how we feel about our audio equipment in ways that we may or may not be aware of. At the moment I believe I prefer the Focal Bathys over the HDB 630, but I’m open to the possibility that a lot of A/B’ing might change that, as much as I love the way the Bathys look and feel on my head.

These are different headphones doing different things, but I’m … very impressed with the HDB630 and if I could only have one of these two pairs, it’s probably the more versatile ones.

Hifiman Audivina

The Audivia are, by most measures, a very odd closed back.⁹ I get why people have so much hatred in their hearts for them (and their new sibling, the Audivina LE). I’m not going to tell you they’re great out of the box, but with *substantial* EQ, I think they’re pretty interesting headphone worthy of an occasional listen. If nothing else, they’re different in a sea of largely the same (and bad).

Without EQ. Out of the box, the Audivina just sound … strange. The treble is VERY bright, though I personally don’t mind the bass and mids balance (even if I’d maybe turn the bass down a hair) and I’ll take the bass presentation over the Aeon x Closed. The soundstage is MUCH wider on the Audivina, with much better layer separation, but the overall sound more palatable on the Aeon. To be clear, I’m not using either of these out of the box without EQ though.

With EQ. This is the more interesting question. With an 8-band EQ system, I can get the Audivina to a pretty decent sound without killing their stage width and layer separation, and I come dangerously close to enjoying them. With a 10-band EQ system, I can get the Aeon to sound genuinely really great, but with a comparatively narrow, not-super-separated sound. As much as I like the Audivina’s staging and presentation, I’m probably not going to use them much unless I’m super bored with everything else,¹⁰ but I definitely prefer the low-end on the Audivina so for some kinds of listening I might gravitate towards them.

And, obviously, the Audivina are gorgeous and relatively unique in the space. Outside of the (awful) Hifiman Sundara Closed and a couple of things like ZMFs, not a lot in the market has this kind of bold appearance. The make the Aeon x Closed’s otherwise striking features look a little tame, and like a safe choice.

So this is not at all what I hear, which makes me wonder if one of my units is damaged. That might explain why I don’t hate the Audivina the way that so many people do, if it’s broken in a specific way that mellows it out. To me, the bass is better on the Audivina (especially volume), mids better on the Aeon x Closed (especially vocals, and especially location in space), treble pretty similar on both.

Capra Ouroboros/Golem Ouroboros

I’m on record as a huge fanboi of the Capra Ouroborous DIY/3D printed headphone, particularly with the Golem mods. I genuinely listen to them a fair amount of the time when I’m working at my desk, and I’ve been enjoying doing a little comparison to various 3D printed headphones as I do reviews of commercial products. This is my chance to talk about one of my favorites.

The Golem Ouroboros gives you substantially better bass (to my ear at least) than the un-EQ’d Aeon x Closed. The mids are a mixed bag; I think the balance is better on the Ouroboros, but the timbre and tone are more correct on the Aeon x Closed. You definitely get better treble control on the Ouroboros, but better detail and sense of space on the Aeon x Closed. And the Aeon is, hands down, more comfortable (as much as I think the Ouroboros are a very comfortable headphone) and has both a wider, and more layered soundstage (the Ouroboros are a very intimate, right around your head presentation).

The Aeon x Closed is a better headphone. Is it $350 better? That’s a hard call to make, especially when you factor in the joy of using something that you built with your hands (and that you can pretty easily tweak to your heart’s desire). I’m going to point most people to the Aeon x Closed, while also offering to help them make the Ouroboros.

[Benchmarking the costs are hard because most 3D printed headphones have an out the door cost substantially lower than almost any audiophile headphone on the market, unless you count printer costs, in which case they’re usually higher. For an example, I calculate the materials costs of the Ouroboros at about $100, but that doesn’t count the test prints, the costs of the printers and their maintenance, etc.]

Overall

Overall, I see why reviewers are so fond of the Aeon x Closed. The closed back market is a weird, shallow one, with not that many genuinely great offerings. The Aeon x Closed makes my list of recommendations, and is a definite improvement from my budget pick, the Fiio FT1. They’ll continue to be my pick under $500, though I like them a lot more around $300 or $350 than their original MSRP of $499.

I’d be really curious to get my hands on another pair of these for additional comparisons; this is the first headphone in a while where there are substantial departures from other people’s measurements and my experience while listening, particularly in the bass regions. I’m a guy who turns bass down on a lot of headphones, and I found myself throughout my listening continually nudging the bass sliders up in Roon’s parametric EQ.

I’m glad that I did listen to Resolve and remove the tuning filters for a lot of my listening; while they did make them more pleasant overall out of the box, I definitely hear noticeably more detail without the filters, even with substantial EQ corrections applied.

#reviews #headphones #sennheiser #6XX #anc #spatialaudio #meh #2025 #99noir #meze #sunglasses #overear #cans #hifiman #arya #stealth #editionxs #budget #hahahaha

1. I score bass, mids, and treble on a two part scale: 1-5 for quantity (5 being the highest), and A-E for quality (A being best in class, E being laughably bad). For soundstage it’s also a two part scale, with the number representing the width and the letter the separation within it. ↩︎
2. For comfort/fit, my scale is A-E with A being disappear entirely into the background and E being I want to tear my ears off to stop feeling these headphones on my head. I’ve had one E: the Koss PortaPro. ↩︎
3. These fit on my head EXTREMELY well, but they don’t have as big a range of possible sizes as some other styles of headbands. ↩︎
4. A really great, reasonably priced DAC/amp with a visualizer mode that warms the cockles of my jaded 80s kid heart. ↩︎
5. Part of DCA’s legacy as a headphone mod company? ↩︎
6. Note; I have zero problems with using EQ, but I tend to swap amplifiers throughout the day and until I figure out how to use NFC codes to apply my EQ profiles automatically, changing from one amp to another means having to swap settings in Roon (often on a computer that’s running effectively headless, as I use the same monitors for my Mac Studio for my work laptop). ↩︎
7. See above for where I ended up. ↩︎
8. Until recently, all my Bluetooth reviews contained this: “Standard disclaimer from other Bluetooth reviews: It’s still Bluetooth so you’re always getting a lossy signal and it gets more complicated when you start using the on-board mic for phone calls.” ↩︎
9. Starting with the fact that they’re only really semi-closed, and extending into their tuning. ↩︎
10. Kind of like the Grell OAE-1; they’re a change of pace headphone when I want something different and weird. ↩︎