Fit and Comfort

Seen above is the HarmonicDyne Athena placed on a mannequin head, to help show how these headphones would look on the human head. Note that the head is slightly under average sized, so account for the discrepancies accordingly. As with all headphones, getting a good fit and seal is crucial, so make sure to properly use the available height adjustability of the headband and the swivel/rotation of the ear cups themselves. This section is mostly a summary of the points expanded upon in more detail on the previous page and I will mention here that the Athena is relatively average in its mass (for dynamic driver headphones) at ~320 g and feels lighter on the head too. This is a testament to the design and weight distribution achieved here, so I'll give props to HarmonicDyne. The good extent of sizing and ear cup movement also helps achieve a good fit and seal of the ear pads around your ears even if I still would have liked to see contoured pads. The pads being quite thick and plush does help alleviate this concern though. I also mentioned how the ear pad opening is large enough to fit larger ears too so that's another aspect to not worry about. The clamp force is about average without any hot spots on my head either and so really everything seems fine here except for the part where the cable connectors come straight down as mentioned on the previous page. If that's not going to be an issue for you—those with wider necks or shoulders might possibly have an issue—then overall I'd say the HarmonicDyne Athena does a very good job in this section. The side-venting also means these are less susceptible to noise leakage going in or out. It can be used in a shared office at moderate listening levels, to give you an idea.

Audio Performance

Audio Hardware

Headphones selling in the same price range as the HarmonicDyne Athena don't do a whole lot when it comes to the dynamic drivers used. If anything, I expect to see an OEM driver used more often than not. Some may go with a slightly customized version in terms of choosing the plating or coating materials used on top of the base diaphragm (mylar, for example) with the goal being to achieve a stiff and responsive driver with good tensile strength. HarmonicDyne has instead changed the diaphragm composition entirely to a metal-ceramic composite alloy manufactured using ceramic carbon fibers at a high temperature. This is why the drivers look different in the photos on the previous page compared to typical such shiny drivers, and this is a 50 mm driver at that. The goal is to achieve a lighter, thinner, and tougher diaphragm which has increased responsiveness compared to others and can generate a higher dynamic range at lower distortion. It is paired with an ultra-fine voice coil made of thinner strands—we do not know the materials used here, presumably aluminium—as well as an efficient magnetic system capable of generating high flux to drive the diaphragm back and forth evenly and rapidly. Then there's the side venting on the ear cups which HarmonicDyne calls an "M-shaped ventilation" with the goal of a more natural soundstage and imaging compared to a fully closed-back set. It makes for a set of headphones which is still relatively easy to drive owing to the rated impedance of 34 Ω (at 1 kHz) and sensitivity of 116.5 dB/Vrms (~102 dB/mW) at 1 kHz. The Athena likely has a higher impedance rating at lower frequencies to where an OTL tube amp might not be the best fit if you wish to preserve the factory tonality but otherwise it can be paired with a decent portable DAC/amp just as well as a more prosumer solid state desktop source.

Frequency Response Measurement and Listening

I will mention that I have a general preference for a warm-neutral signature emphasizing a slightly elevated bass and smooth treble range with detailed mids and good tonal separation. I also generally prefer instrumental music over vocals, with favored genres including jazz and classical music.


Our current headphones test setup uses a set of two custom in-ear microphones for the two channels. These microphones closely adhere to the IEC711 class, but have been tweaked to be more reliable in the >10 kHz frequency range, the precise issue with my previous setup, that is otherwise still very good and will continue to be used for IEMs and earphones. Two soft silicone pinnae are installed on the sides, separated by a distance matching my head, and multiple "height" adapters have been 3D-printed for further customization, based on fit, head size and shape. Each set of microphones has an XLR output I separately adapted to 3.5 mm. I used a transparent source—the JDS Element II—for measurements after confirming it was not a bottleneck in any way. This artificial head simulator feeds the microphone lines into a reference USB sound card, which in turn goes to a laptop that has ARTA and REW running. I begin with an impulse measurement to test for signal fidelity, calibrate the sound card and channel output, account for floor noise, and finally test the frequency response of each channel separately. Octave smoothing is at the 1/12th setting, netting a good balance of detail and signal to noise ratio. The default tuning was used for testing, and no app or program-based EQ settings were chosen, unless specifically mentioned. Each sample of interest is measured at least thrice with separate mounts to account for any fit issues, and an average is taken of the individual measurements for statistical accuracy.


As per usual, you can find my headphone frequency response measurements on VSG.squig.link, along with all the earphone measurements. Scroll to the bottom and choose different targets there, including two from Harman Kardon, developed after years of R&D. The Harman 2018 over-ear target in particular is a reference curve many headphone makers aim for now, but I find it too bass-boosted. As such, I am opting for the Harman 2018 curve with the bass target from the Harman 2013 curve, which is what is being referred to as the "Harman Combined" target there. Before we get talking about the sound signature of the HarmonicDyne Athena, I want to first talk about the channel balance achieved here. You will notice how the left and right channels are quite close to each other in the lower frequencies and them exhibit some imbalance in the low-mid treble. In practice I did feel a small amount of this mismatch from 5 to 6 kHz but not really afterwards to where the latter difference at 10 kHz may be a measurement anomaly. I am not sure what level of driver matching is being done here but it's okay at best and won't win any awards based on my sample. I will also mention that using the headphones for ~50 hours didn't change anything either for those who would undoubtedly be curious about burn-in.

HarmonicDyne has a factory frequency response curve on the product page which differs from my findings. Some of this discrepancy can be down to the angled drivers not necessarily lining up with the IEC711 coupler positioned in my measurement rig, especially when it comes to the 1-4 kHz drop in the measurements. Yet I will say that some of this is also how I heard it in my ears and the semi-closed earcups make it all the more plausible that we have a gentle V-shaped tonality as opposed to a fully balanced one that HarmonicDyne claims. The side-venting helps to a good extent although the ear cup resonance has to dissipate somewhere as we have seen in the past with other closed back sets. Having gone from a more neutral set to the Athena also made this set come off shouty by comparison to where the extra energy in the lower treble from 6-8 kHz can even be off-putting and sibilant relative to the recess right before. This makes for challenging female vocals as well as string instrument reproduction and an overall concern for me since HarmonicDyne was never able to get back to me to address my findings being different from their own.

The good thing is the lower frequencies are fairly well put out. There is a slightly warm tonality in the lower mids which builds to a mild bass shelf too. It keeps the details intact without any muddiness or bloat while helping make the Athena quite conducive for general media consumption and podcasts alike. I know first hand several people who preferred this for watching movies too since it does not overpower you with too much bass and yet allows impactful sounds to take center stage. When it comes to music listening, I have less positive thoughts since the Athena feels like its trying to do a lot of things but doesn't do them well enough. The sub-bass extension is probably the most positive thing to note here, although even here it's not exactly a set with plenty of slam. The mid-bass would have benefited from an increased dynamic range—something this new driver claims to do but I don't really feel it in person. Trailing ends of notes get lost in a slight haze which affects imaging to an extent despite the good instrument separation in the mids. Soundstage does feel plenty natural and wide enough though, especially knowing this is a semi-closed set at the end of the day. I can see some music genres working well here including classic rock and pop, maybe also country music.


Semi-open or semi-closed headphones are rare in general so comparing the HarmonicDyne Athena gets tough even if you expand the price range of interest. In a sense then you could also compare it to both open and closed sets so I chose to go with the former in the price range the Athena belongs in given the overall tonality and sound still feels closer to an open-back set except for the bass shelf derived from a closed-back DNA. You could check out my reviews of the Sivga Robin and Oriole then, and then come back here to see how the Athena handles itself against the likes of theDrop x Sennheiser HD 6XX. If you are in the USA then the HD 6XX is an excellent buy for the money which gives you some of the very best mids at any price level, and the Athena is almost an inverse with its tonality. Both are quite comfortable to wear over longer periods of time and feel they will last long too given the decent build and the replaceable pads. But if I had to pick one then it would be the HD 6XX for doing a few things very well, which is more than I could say about the Athena. Funnily enough, I do think the more expensive HarmonicDyne Zeus is a suitable comparison here. We have a similar design although the Zeus bests the Athena with its accessories, and note how we get a very similar tuning here except with the bass extension being far more prominent here. The Zeus comes off warmer, arguably with more punch, and has a wider soundstage too. In return, the Athena has better mids reproduction for vocals and brass instruments and you can get most of the Zeus's offerings at a lower cost. The tougher competition comes from the warmer tuned open back sets such as the Philips Fidelio X2HR (if you can still find one), the more expensive FiiO FT3, and the MOONDROP VOID. The VOID promised so much but failed harder to where the Athena feels way more premium by comparison and even has better technical performance too. The VOID gets tonality better though so you need to decide what works better for you. I'd probably pick the Athena here simply because it won't turn pink or yellow over time and does not sound dead inside. The better build quality and aesthetics are a bonus on top.