HarmonicDyne Athena Measurements and Review

Opening

Half on a whim, I secretly pre-ordered a mysterious pair of headphones a couple of months ago. It’s obviously a gambling choice -- who can dare to look forward to a success from the combination of $160 new, China, and an unknown company (among audiophiles)? Haha.

Aside: Accurately speaking, not 100% gambling for me.. I listened to this company’s prior products, and I got the sense that they were learning something incrementally at every step of the way. At least I was confident that the product I ordered wouldn’t sound too crappy.

One month or so later, the headphones finally arrived at my place. After impressive unboxing, I gave them immediate listens. I was prepared to face compromises that fit the price point. But I couldn’t help but gush.

Holy shit.

They sounded really good -- much better than expected. Ok, I might be over-enthusiastic with getting a new toy. I decided to cool off and listen for another two weeks, but so far I haven’t found anything to contradict the fact that the company has overachieved.

Yes, folks. This is the product I am going to review in this thread, called Athena. A semi-closed pair of headphones that was released in China this spring by HarmonicDyne. Let’s find out why I was blown away.


Aesthetics / Design / Comfort

Athena is decent looking for the price. The use of glass-like hard plastic (I think) in the backs of the cups and the ends of the headband looks a bit sleek, in exchange for the maintenance inconvenience -- this shiny plastic is very easy to get fingerprints on, which required me to be more careful and clean more frequently. Its build is solid although there aren’t as many metal parts as HarmonicDyne’s prior products (which are all more expensive). Looks and feels very sturdy/solid to say the least.

The company calls Athena “semi-closed” but I think that is a bit misleading. When we say open/closed/semi-open/semi-closed, we usually mean how open the back of each cup is. Athena’s cups are closed at the back. It just has large vents on the side. See this (from the product page). It sounds more like open-backs than closed-backs though.

Athena is quite comfortable in my head. It’s not very light, weighing 345g on my scale. But the weight is well distributed by the soft padding on the top, which has a large contact area. I also like the ear pads (they look like Ether pads in shape). They have perforated pleather on the inside and suede on the outside and front. They feel just right, comfortable, and soft. Overall, Athena gave me a very comfortable wearing experience.

 

Listening

As usual, my evaluation was done with the M500.3 dac-amp and the HO200 headphone amplifier. I mostly compared Athena to my HD560S and HD650 (KISS-modded).

The Athena’s sound departs from what I consider to be measurably-neutral. During my listening sessions, I found the Athena’s balance to be experientially-neutral, which compensates for my ears being less sensitive to bass and treble at the volume level I use. I suspect that HarmonicDyne proactively used equal-loudness compensation to tune Athena’s tonal balance. More on this later in the thread.

The low frequencies were powerful and extended with a good authority/control. I’m very impressed with the punchy kick drums and the weighty bass guitars that Athena reproduces. Athena’s bass is also great in micro stuff -- nothing to complain about articulation, delinearation, or texture. I am doubly surprised that Athena does bass far better than its older brothers.

Moving on to the midrange, one of the first things I noticed when listening to the Athena was that vocals sounded a little more distant than I was used to with other headphones. This in itself is usually considered a bad thing. But what’s different with the Athena is that the whole “repositioning” thing is done convincingly and actually helps me pick up details better in the wider spectrum, and the overall harmonic level in the reproduction is even higher. Vocals sounded present/detailed enough, albeit distant. This reminded me of the ZMF Verite , which had a receding upper midrange, but resulted in a very convincing reproduction.

There was also some coloration in the midrange. Occasionally things sounded a bit thinner or unnaturally clear. Some female vocal tracks also show more nuanced energy in the upper midrange. These mostly work well in the grand scheme of how the Athena is tonally tuned, but there were a few moments where I thought the Athena was not perfectly neutral in the midrange game.

The Athena’s treble is relatively quite elevated. I emphasize “relatively” because it’s mostly noticeable in the comparison with the neutral reference like HD650. The treble sounds very reminiscent of the HD800/SDR I used to own, but from memory, I think the HD800/SDR was a little less tame and more biting/sibilant. Examining sibilance with many harsh test tracks, the Athena surprised me how it could handle many vocal sibilances within my tolerance, although its treble is rather on the bright side. Throughout the entire presence and brilliance range, the Athena really shines in terms of clarity, smoothness, and cohesiveness. And this solid treble performance is highly synergized with the inherent microscopic capabilities, resulting in the best resolution in its class.

The soundstage is decently large and well-defined. Lateral width is between HD650/Kiss and HD560S. Closer to the HD650. Athena layers and positions the acoustic objects in the soundstage almost correctly. The presentation is a bit wrapped around the boundaries. The more time I spend with the Athena, the more I believe its presentation makes sense and is natural. It turns out to be better for the overall harmony when the vocals are pushed back a little. At least to my ears.

Athena also has a very unique timbre. I found Athena’s timbre was drastically different from the HD560S’s digital-ish and overly-articulate style (which I like!). Compared to the HD650/Kiss, Athena’s timbre is bolder and more romantic. Athena also has a more natural and organic decay. Maybe too emotional at times? Quite interpretive and musical in a modern way.

The best part of Athena for me was that it allowed me to rediscover. I listened to familiar recordings and tracks as if for the first time,and had to enjoy almost everything with a fresh mind. This is exactly what I strive for with every audio purchase. Athena can also handle a wide range of genres that I listen to -- from baroque pieces to modern jazz to kawaii/future bass tracks. I won’t say that Athena is as capable as my multi-grand references (Stealth+Susvara) -- because it’s not. But I have always wanted to hear another track with Athena as much as I did with the stable references. As a person whose ears have been marinated in summit-fi headphones, this is not a compliment that I often pay to budget-level products.

 

Measurements

As usual, my measurements were taken with the MiniDSP EARS at 95db SPL@300hz with the homebrew hybrid compensation target curve that mixed HPN, HEQ, and additional adjustments based on B&K Room Curve.

Please note that my frequency responses are averaged results based on 5 different positions (center/up/down/front/back) to control positional variance. Results from optimal positioning might differ even with the same measurement fixture/rig.



The FR is obviously V-shaped with +10db elevation in both bass and treble (or alternatively -10db recession in mids). It’s more V-shaped than I actually perceive, especially in the treble. And I believe this discrepancy between measurement and perception is strongly associated with what ISO equal loudness contour around 80-90 phon suggests. As per the ISO contour at 80 phon (=equal loudness to 80db spl at 1khz), human ears are less sensitive in both highs and lows roughly by 10 decibels. And the contour starts to soars up at higher bands starting at 4khz, which is shown in the Athena’s FR, too.

Of course, the amplitude of actual music is not constant but dynamic, and my listening volume at peak is higher than 80 db spl at 1khz. These factors make adjustment very complicated -- almost impossible to achieve perfect neutrality in perception by static adjustments. And probably this is the reason why I still perceive Athena’s response as ‘mild V’ rather than flat-neutral. Nonetheless, it’s interesting to see that V-response can benefit my listening pleasure as long as it is carefully tuned. Verite taught it to me, now Athena re-assured me. Note that I don’t necessarily mean Verite and Athena sound/measure close. The way they both convince me is somewhat similar though. See below.



The two dips at 1.3khz and 3.9khz in the Atehna’s FR are also interesting. I didn’t hear those two dips per se, but it seems they relatively elevated surrounding frequencies to result in good clarity and presence in perception. A sudden drop at 1khz also turned out sustained energy in disguise (shown in the waterfall plot).

Spoiler: Athena's waterfall plot (experimental)

Please acknowledge that waterfall plots in headphones can be controversial and that measurements in non-professional rig may be misleading.

I also found strong resemblance with HD800/SDR in my listening. The measurement confirmed it to some extent. Major differences found in Athena include better extension, more nuance around upper mids, and a little politer highs. See below.



I’m also attaching comparative plots against HD650/Kiss and HD560S below.



Finally, although I don’t give much credit to distortion measurements unless taken in well-designed isolation chambers, I found Athena’s harmonics are relatively well controlled across the entire spectrum. It suffers from high H3 levels below 100hz, but approximately at the similar level to H2. Below are measurements of Athena, HD650/Kiss, and Mini-S (measurements taken at 95db spl) -- I think all of them exhibit good distortion control for non-planar/non-electrostatic headphones.

Spoiler: Athena/HD650/Mini-S distortion measurements

As I said, these can be inaccurate in many ways. And I believe that, when measured in a well-designed acoustic isolation chamber, all the distortion values will drop by orders of magnitude.