Dan Clark Audio Aeon 2 Open vs Closed - Planar Headphone Comparison

Written by Chrono

Review units provided on loan for evaluation by headphones.com

Introduction

The AEON 2 Open and AEON 2 Closed are portable, planar-magnetic headphones from Dan Clark Audio intended for audiophile listening. The AEON 2 Open and AEON 2 Closed both retail for $900 and are the successor to Dan Clark Audio’s AEON Flow Open and Closed, and they feature improvements in their driver technologies that improve airflow, resolution, and dynamics.

Sources and Music Used in Listening Tests

The Amplifier/DACs used in this review were the ifi Micro Black Label and JDS Labs Element II connected via USB to my desktop computer. For the listening tests I used music from a wide variety of genres including Rock, Jazz, Classical, Acoustic, Hip-Hop, and latin. I played tracks from my own FLAC library as well as from Qobuz streaming service played via Roon (exclusive mode).

Power Requirements

Despite clocking in at an impedance of 13ohms, the AEON 2’s are rather power-hungry headphones. This makes more sense when looking at its sensitivity level, which is only 94dB/mw on the Open version, and 92dB/mw on the Closed. The AEON 2 has been the only headphone that has required me to run my ifi iDSD Micro Black Label in “normal” (second gain stage) as opposed to “eco” (lowest gain stage). I highly advise that you listen to these with a discrete headphone amp, as listening to them straight from my MacBook made them sound compressed by comparison.

What’s in the Box?

*Everything In this section applies to both the Closed and the Open version of the AEON 2

Included with the AEON 2, you get a couple of nice accessories. For starters you get what Dan Clark Audio calls their “DUMMER” cable that measures 2m in length and is made of a very nice, flexible fabric. For connections, the cable uses hirose connectors for the headphone side, and they terminate in 3.5mm for the amplifier side; a thread-on ¼” adapter is also included. Also included is a custom-molded hardshell that is very compact and ideal for travel. Lastly, you get three different sets of filters that you can place in the insides of the cups to slightly refine the AEON 2’s sound to your taste by providing different levels of damping–I will discuss their sonic changes more in depth in the sound section of the review.

Build Quality and Comfort

*Everything In this section applies to both the Closed and the Open version of the AEON 2

The AEON 2’s build is spectacular; both visually, and its construction. For a planar-magnetic headphone it is remarkably compact, lightweight (327g), and it also features a very good, collapsible, folding mechanism that further reduces its footprint. The earcups use a mix of metal and plastic, which gives them a light but very solid feel. The use of the metal alloy, nitinol, gives the headband a very durable structure all whilst remaining extremely light and flexible. I think the AEON 2 has one of the best builds and designs I have seen on a headphone, and I don’t really have any complaints about it; just very solid overall.

Comfort on the AEON 2 is also outstanding. The pads follow the shape of the ear, and whilst that makes them look a little narrow, I had no issues getting a good fit with them without touching the inner sides of the pads. They are also fairly deep, so I never found that my ears came in contact with the driver. The pads are wrapped in a very nice, protein leather that–in my experience–generated less heat build than I usually get when compared to lambskin pads. The only real issue I had was that the AEON 2 was a little bit on the clampy side, but they were definitely not as vicious as what you get with a Sennheiser HD 600-series headphone.

Sound

This is my first experience with Dan Clark Audio headphones, so I was not sure what to expect before listening to the AEON 2 Open and Closed. In each of their own, unique ways, the AEON 2’s really surprised me. Both headphones have similar traits, and the only visual differences are that the AEON 2 Closed has a carbon-fibre insert covering the area where the grills would be, and that the AEON 2 Open has partially-perforated ear pads. Yet, despite their similarities, one of these two nearly-identical headphones has me going “woah, I like that,” whilst the other has me thinking “woah, I really don’t like that.”

For this sound section, I’ll be discussing the tonality and technical performance of each AEON 2 headphone, drawing comparisons between them and also comparing them to other headphones around their price range.

Bass

I will start off by talking about the AEON 2 Open’s bass because it is the more interesting of the two, and then I will cover the AEON 2 Closed’s bass and how they compare.

I think that I would describe the AEON 2 Open as having a somewhat “V-shaped” sound signature, but with a rather exaggerated rightward skew. The AEON 2 Open’s bass is remarkably overbearing; with a wide, mid-bass elevation at around 130hz in an excess of 8dB. This is undoubtedly one of the most problematic qualities in the AEON 2 Open’s sound signature as it makes bass notes sound very boomy, and bloated.

Additionally, because it is a very wide elevation, the upper-bass bleeds severely into the lower mids and makes things like low piano, guitar and vocal tones between 250hz-500hz sound extremely congested and undefined. Now, detail in the bass is actually pretty good on the AEON 2 Open and–as expected from a planar-magnetic headphone–it has fantastic extension that makes the bass sound very deep. However, I feel like those good qualities which the AEON 2 Open possesses in this region of the Frequency responses are easily shrouded by its bass tuning, which is simply out of control and makes for a rather muddy listening experience.

The AEON 2 Closed, by comparison, still has a touch of added warmth in the bass around 130hz, but it is a lot more subtle and tasteful; which I think makes it pretty enjoyable on some tracks, as it also adds a slight mid-bass punch without feeling like it really upsets any of the other frequencies in the mix. I still feel as though the upper-bass creeps ever so slightly into the lower mids, but–again–is nowhere near the same level as on the AEON 2 Open. This, to me, was actually quite surprising because I expected the AEON 2 Open to have a more balanced bass response, but it was actually the closed-back version that performed better in that regard; and of course it retains the great extension and detail that its open-back counterpart can present. Overall, I think that both the AEON 2 Open (after EQ) and AEON 2 Closed have very good articulation in the lows, but I still found the HiFiMan Ananda, LCD-2 Classic, LCD-2, and LCD-GX to be a little more refined and well-defined in this region of the frequency response.

Midrange

Starting again with the AEON 2 Open, it sounds to me as though the midrange can easily get lost on the mix when compared with the elevated bass and treble. The congested lower-mid tones completely overpower the rest of the midrange, and makes it feel quite stuffy-sounding; vocals lack presence, electric guitars sound very distant, brass instruments lack their bite, and it generally just feels as though the only thing letting you know all these different musical elements are there is their overblown harmonics and overtones in the treble region. I personally find this to give the AEON 2 Open’s sound a very off-putting and unnatural tonality.

The AEON 2 Closed’s midrange is not perfect, either, but it is presented in a way that I find to be much more enjoyable than on the AEON 2 Open, and it never strikes me as sounding particularly unnatural. As I mentioned earlier, it is not affected nearly as much in the lower midrange, so it does not sound congested in the way that the AEON 2 Open does. The midrange on the AEON 2 Closed sounds to me like it actually has better body and substance than its open-back counterpart, although it does have a wide 3dB-4dB recession in the upper-midrange between 1.5K-5K, which which took away some of the presence for instrument and vocal overtones in that region of the frequency response, and made the mids sound slightly hazy and less resolving.

I find both the AEON 2 Open (after EQ) and AEON 2 Closed to have very good midrange resolution, but after using EQ on both models I actually find that it is the AEON 2 Closed to have the slightly cleaner and more detailed midrange. When compared to other planar-magnetic headphones in its price range, I personally find the AEON 2 Closed’s mid range resolution to be particularly great, as I think it is slightly more resolving in this region of the frequency response than the LCD-2 Classic, Ananda, and it is only slightly edged out by the LCD-GX; which I think is very impressive for planar-magnetic closed-back headphone that is as compact as it is. I also thought it was worth mentioning that I personally found the timbre for both the AEON 2 Open and AEON 2 Closed to be surprisingly reminiscent of that of dynamic-driver headphones, which I thought made them sound a little more natural than its planar-magnetic competitors.

Highs

The AEON 2 Open and AEON 2 Closed have some common characteristics in the treble region, but their presentation ends up sounding completely different. They both have peaks at around 6K and 8.5K, but they are significantly more exaggerated on the AEON 2 Open. The AEON 2 Open’s treble peaks are excessively accentuated, as they are significant in magnitude and are also fairly wide in their rise. This excess in treble makes the AEON 2 Open’s highs come across, to me, as extremely aggressive, sibilant and piercing. Also, as I mentioned earlier, the overtones and harmonics in this region are blown unnaturally out of proportion, which makes vocals, drums, cymbals, drum strikes, and brass instruments sound harsh whilst also introducing a strong, sizzle-like quality.

On the other hand, the AEON 2 Closed’s peaks are much narrower, and smaller by comparison. The AEON 2 Closed had a bit of glare as a result of the 6K peak, and whilst it did not sound particularly sibilant to me in that region, I do feel as though it adds a slight emphasis to the upper-midrange recession that precedes. The 8.5K peak on the AEON 2 Closed can occasionally add a little bit of pierce and make some consonants sibilant, but it was not anywhere near as bothersome as on other headphones like the DT 1990 Pro or AEON 2 Open. One quality that both headphones had in common, however, was that to me it sounded as though they had a little too much air in the region above 10K, so vocals and certain instruments had a little too much of that upper treble glisten. This was not an offensive quality, but one that I thought I would point out as, to me, it sounded just a little bit unnatural.

For resolution in the treble-region, I think that the AEON 2 Open (post EQ) and AEON 2 Closed perform really well, and once again I find that the AEON 2 Closed actually delivers a slightly cleaner image of the highs. To me, it sounded as though both of the AEON 2’s were a little more resolving than the LCD-2 Classic, but still lagged slightly behind the Ananda, LCD-2, and LCD-GX.

Soundstage, Imaging, and Layering

This is an interesting set of categories, because both AEON 2 Open and AEON 2 Closed perform almost exactly the same. The AEON 2 Open is a very closed-sounding headphone, and has a very intimate presentation that feels only ever-so-slightly wider than the AEON 2 Closed. Dan Clark Audio claims that soundstage has been improved from the original AEON Flow models, but I cannot comment on that as I have never heard either of those headphones. Still, I can compare to other headphones that I have listened to, and I can say that they are very narrow in their soundstage width and they have a less spacious presentation than that of an HD 600-series headphone; so they are definitely a little underwhelming in their sense of width. Imaging on the other hand I think is quite good, I find that the AEON 2 is able to depict sounds’ sense of direction extremely well and has no gaps; sounds are able to pan very smoothly from left to the center and to the right. Instrument separation and layering is also excellent. The AEON 2 Open and Closed play within a very small stage, but every instrument and element in the music sounds very well-defined and has its own, well-defined space. Overall, I really enjoy the soundscape that the AEON 2 Open and AEON 2 Closed present, as it is intimate without ever feeling cramped or claustrophobic.

Dynamics

The AEON 2 Open and Closed, unfortunately do not possess the most impressive sense of punch and slam, as Focal and Audeze’s offerings both outperform in delivering that satisfying, physical sense of impact in the low-tones. Now, whilst things like drum kick impacts will not have as much weight on the AEON 2 Open and Closed, they are still able to very nicely reproduce that top-end attack behind drums, piano keystrokes, xylophones, and the tension of string instruments in a realistic fashion. Overall, whilst they do not have the most impressive, most engaging dynamics I still think they perform better than headphones like the Ananda and HD 660S; which I think is worthy of merit considering that the AEON 2 utilizes an extremely light-weight, single-sided magnetic array for their driver.

EQ and Filter/Inserts

As I mentioned earlier the AEON 2 Closed and Open both include a couple of different filters with varying levels of damping. The included filters are a set of foam filters (lightest), black filter (medium density), and white felt filter (densest) and they all aim to allow users to adjust the treble to their preference. From my experience, it seems like they target the 8.5K peak the most and they do it fairly well, but it does have some effects on resolution. When using the filters I feel like the bass and mids in particular lose just a little bit of their cleanliness, and how much resolution is sacrificed increases with the level of density; an unfortunate trade-off incurred by front-damping the driver.

For EQ, I will start with the AEON 2 Open as it is the one that needs it the most desperately. I use a combination of low shelf filters to tame the bass into more normal levels and reduce the lower-mid bleed that congested the AEON 2 Open’s tonality. Additionally, I use some pretty drastic peak adjustments at 6.5K and 8.5K to quell the treble down a bit. After using EQ, the AEON 2 Open sounded a lot more natural and balanced to me. Now, whilst the EQ I used made the sibilance, sizzle, and pierce go away for the most part, the AEON 2 Open still seemed to retain a bit of a strange harsh quality. If you are interested in trying out my EQ for the AEON 2 Open, the settings I used were:

AEON 2 Open EQ

  • Low Shelf at 100hz, +6dB Q of 0.7
  • Low Shelf at 300hz, -7dB Q of 0.7
  • Peak at 6000hz, -7dB Q of 3
  • Peak at 8500hz, -5dB Q of 2
  • High Shelf at 11000, -3dB Q of 0.7

The AEON 2 Closed I do not think needs EQ, but I did want to relieve some of that 6K and 8.5K peakyness, as well as the upper-midrange recession between 1.5K to 5K whilst bringing it closer to my personal target (which is fairly similar to the Harman Target. If you would like to try my EQ preset for the AEON 2 Closed, these were the settings I used:

AEON 2 Closed

  • Peak at 130hz, -3dB Q of 1.2
  • Peak at 300hz, -2dB Q of 1.4
  • Peak at 2500hz, 3dB Q of 0.7
  • Peak at 6000hz, -4.5dB Q of 4
  • Peak at 8500hz, -2.5dB Q of 6
  • High Shelf at 11000Hz, -3dB Q of 0.7

Conclusion

I think it is strange that, in a way, the AEON 2 Closed feels to me like a refinement in every way when compared with the AEON 2 Open. From my experience listening to both, I was really hard-pressed to find anything that the AEON 2 Open offered over the AEON 2 Closed. They both offer a fairly energetic tonality, with accentuated highs and very present, warm bass; however, the AEON 2 Closed is able to present that sound signature in what I think is a much more tasteful and enjoyable way that does not sound oddly dark and shrill in the way that AEON 2 Open does.

Having said that, there are a few takeaways for me after listening to both of these Dan Clark Audio headphones. The first thing is that, knowing how the Closed-back performs and sounds, there is no scenario in which I would find myself recommending the AEON 2 Open; the AEON 2 Closed overall performs better and I find it to be significantly more enjoyable with or without EQ. The other thing I wanted to mention is that if you are looking for a planar-magnetic headphone in the $700-$1000 range, I truly believe that as long as you are willing to sacrifice some dynamics and soundstage the AEON 2 Closed should be a strong contender in your shortlist amongst headphones like the LCD-2, Ananda, and LCD-GX; as it offers the most unique package among them with great tonal and technical performance delivered in a comfortable, portable, lightweight, closed-back package.

- Chrono

Watch the video comparison here:

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