HarmonicDyne Zeus Open-Back Headphones Review

zeus side grills

HarmonicDyne is a newcomer to the headphone scene. Their presence is immediately felt because, unlike IEMs, Chi-Fi headphones are not very common. The few that currently exist in the market are pretty much hit or miss and are often forgotten once the hype has died down. 

They made their grand entrance in the audiophile scene with the HarmonicDyne Helios. And while it was not a perfect headphone, it showed that they are a very capable brand that can produce a great product with enough time and experience. 

Now they are back with the more premium HarmonicDyne Zeus. It features the same wood and metal design aesthetic as the Helios but has more refined drivers and better overall technical performance.

The price point that Harmonicdyne has chosen to place the Zeus in is very interesting because it is challenging established models in the headphone scene such as the Sennheiser HD6XX Series and the HiFiman Sundara

But with its higher price point, it raises some questions regarding value. Is it worth spending this much on a headphone that hasn’t proven itself? 

In this review, we will be answering that question. We will be putting the HarmonicDyne Zeus through its paces and find out how good its build and sound quality is.

We will also find out how well it pairs with different sources, and most importantly, we will be comparing it against the very popular Sennheiser HD660S

And by the end of this review, you should have a better idea of whether or not the HarmonicDyne Zeus fits your tastes and needs. Find out more by scrolling down below. 

Disclaimer

We would like to thank Linsoul for providing the review unit and for making this review possible. However, this does not influence our review in any way. Everything written here is my honest opinion.  

HarmonicDyne Zeus Review

Packaging and Accessories

zeus carry case

The HarmonicDyne Zeus is arguably one of the best headphones that we have unboxed, especially at this price range. And that is saying a lot since we have checked out more expensive headphones from the likes of Sennheiser. Most of the time, we either see minimal packaging that only contains some branding or flashy boxes with gorgeous art. 

However, the HarmonicDyne Zeus does not even come with a box. The Zeus comes with a nicely built flight case that rivals the size of professional microphone cases. It is built very well and gives you the confidence that the headphones will arrive at your doorstep without a scratch. 

The flight case adds plenty of value to the Zeus and is more practical than your standard cardboard packaging. Its premium looks and stealth black design makes this the best way to store and transport the headphones.  

zeus case internals

Once we open the case, we can see that the headphones and the accessories are neatly packed. Every accessory has its own compartment and the whole case has enough foam padding to keep them safe. There is some paperwork that contains the specs of the headphones, which gives us a quick glimpse of the Zeus’ technical performance. 

The hard case isn’t the only star of the show here. The HarmonicDyne Zeus comes with a lot of accessories and pretty much covers everything you would need. It comes with the stock cable as well as some adapters. We will be talking about those in more detail in their own section below.  

Overall, the Zeus is off to a strong start with its initial presentation. I was not expecting to be blown away by how much value the Zeus brings to the table. The hard case alone is something that even higher-end headphones do not have. But before we get too excited, let’s check out how well the Zeus’ build quality stacks up. 

Accessories:

  • Stock Cable (4.4mm balanced pentaconn)
  • 4.4mm pentaconn to 3.5mm adapter
  • 3.5 to 6.35mm adapter

Design and Build Quality

Headphones

zeus side grills alternate shot

Just like its packaging, the aesthetics and the build quality of the HarmonicDyne Zeus does not disappoint. The Zeus is a very eye-catching headphone, particularly because of its grill design and its use of wood. Most audiophile and professional headphones go for a more muted and minimalistic look. However, the Zeus goes for a more daring approach that helps differentiate itself from the rest of the competition. 

The combination of the materials used for its build makes it a gorgeous looking and sturdy-feeling unit. The ear cups and the sides of the headphones are made of wood while the rest of the headphones, except for the upper part of the headband, is made of metal. 

The overall build and craftsmanship are very solid, with no creaking or any obvious weak points. There are some plastic parts, but they are not very obvious and are used sparingly in non-critical areas. 

zeus cable port

The only critiques that I have for the Zeus’ design and build quality is the side adjustments, the Left and Right indicator, and some minor imperfections. HarmonicDyne chose to go with a more unique approach for the Zeus’ side adjustments. 

And while they do not feel flimsy, I am not sure how well they hold up compared to more traditional designs. They have, however, not loosened up during my testing period and have overall held up very well.

zeus side writings

As for its aesthetics, the left and right indicators look too large, and the font doesn’t fit the overall aesthetic of the headphones. Also, the side grills are somewhat unrefined and feel a bit sharp to the touch. 

But these are just some minor issues that do not greatly impact the build quality of the HarmonicDyne Zeus. Overall, I am very happy with how the Zeus is built very much in line with what is expected for its price. 

Cable

Note: Older units seem to have a different stock cable. Our review unit is utilizing the most updated revision. 

zeus stock cable

The HarmonicDyne Zeus comes with a nicely made 4.4mm balanced pentaconn cable. This is a very nice addition since a lot of modern headphone amplifiers, DAC/Amps, and DAPs come with this option. 

However, users who do not use balanced connectors should be fine since the Zeus comes with a 4.4mm to 3.5mm adapter. I am a big fan of balanced cables, and I wish more companies would start adding including them out of the box. 

In terms of the build, the Zeus’ stock cable is very good. And while it does have a DIY vibe, especially with how the braiding is done, I find it better compared to the basic rubber cable that came with my Sennheiser HD660S

The cables utilize 3.5mm for its connection, which makes them very easy to replace. I am glad that HarmonicDyne went with this rather than an obscure or proprietary cable. 

In terms of the connectors, metal is used on both the 3.5mm and 4.4mm housing. They feel very sturdy and won’t break during connection and disconnection. Also, the design of the metal is consistent and looks similar throughout the cable. 

The only possible critique that I have is that the non braided area above the Y-split has a plasticky feel. But aside from that, the cable feels very good and perfectly compliments the headphones. 

Adapters 

zeus included adapters

The adapters that come with the Zeus are very good quality and are not just throwaway additions. This is very crucial since a lot of users are potentially using the Zeus with a 3.5mm or a 6.35mm device.

I personally use the Zeus with my Audient Evo 8 which uses 6.35mm for its headphone output.

zeus adapter length

The included 4.4mm to 3.5mm adapter looks very good and follows the aesthetics of the cable. The only criticism I have is that the adapter is straight which makes the connection too long.

And while it is still practical to use, I would have preferred an adapter with an angled and smaller footprint such as the ones by ddhiFi

Comfort

zeus inner grills

The combination of wood and metal gives the HarmonicDyne Zeus some serious heft. However, I do not find its weight to negatively impact its comfort. 

They certainly do not disappear in my head once I wear them, but they also do not cause any discomfort. Even after long listening sessions, I did not find any buildup of pressure in the ear pads or the headband. This is possible due to the good distribution of weight and the well-made earpads. 

zeus with evo 8

The earpads are large, soft, and spacious. I found them to be comfortable right out of the box. The clamping force was perfect for me but some users may need to break them in if they find them too tight. 

The padding on the headband is adequate. However, I wish they used the same velour material as the earpads. The pleather material may wear out over time so I wish if they at least made it easily replaceable. 

But overall, I have no complaints when it comes to the comfort. Throughout my testing period, these headphones have served me well as my daily driver. 

Power Requirements 

zues with tc44b

The HarmonicDyne Zeus isn’t particularly hard to drive. It is rated at 64-ohms and can be theoretically powered with most devices.

Everything from my portable DAC/Amp to my audio interface was able to provide adequate listening volume. 

But with that said, I still highly recommend pairing the Zeus with a high-quality source. Like most headphones at this price range, the Zeus greatly benefits from having more power at its disposal. 

Sound Quality

Tested with: Fiio M11, iFi Nano iDSD Black Label, Audient Evo 8

Presentation

zeus with fiio m11

The best way to describe the HarmonicDyne Zeus’ sound signature is fun and enjoyable. Unlike headphones such as the Sennheiser HD600 series or the Beyerdynamic DT 990 Pro/DT 1990 Pro, these headphones are not meant to be a critical listening pair. 

Its sound signature is warm and slightly V-shaped and has more emphasis on the lower mids and low frequencies. And typically, I do not lean towards these kinds of headphones as I enjoy listening to more neutral and brighter pairs. 

But despite that, its sound signature did not stop me from enjoying these headphones. In fact, this has been my daily driver because it is very easy to listen to and fits well with almost any music genre that I have thrown at it. 

Anything from complex orchestral pieces to simpler tracks all sounds very detailed and enjoyable. And with its well-controlled treble, I did not encounter any hearing fatigue. 

But the real party trick here is its imaging and soundstage. It is surprisingly very wide and presents a spacious listening experience. 

zeus with beam 2se

While it isn’t quite on the same level as the Sennheiser HD800S, it is wider than a lot of established players in the market. The imaging is also phenomenal for its price range. This is very evident in a well recorder track or in live recordings. 

The positioning of each instrument and all the small nuances in these kinds of tracks are easily heard. This also makes the HarmonicDyne Zeus a very good option for gaming.

The detail retrieval of the Zeus is no slouch either. Small nuances in songs can be easily heard and the overall technical performance is comparable to the established brands in this price range. 

Bass

The HarmonicDyne has excellent bass for a dynamic driver open-back headphone. It is very punchy, and its impact is easily felt. They give excitement to tracks that need it but are done tastefully to preserve the intimacy of more laid back tracks. 

But with that said, the bass isn’t elevated and does not stick out in places where it should not be. It provides support to both the mids and highs but does not attempt to be the star of the show. And overall, the bass adds some needed thickness to the low end to help achieve a full sound. 

Mids

Compared to the lows and highs, the mids are more recessed. They aren’t buried in the mix, but it is very evident that they are not the focus of the Zeus. But with that said, I still greatly enjoyed the HarmonicDyne Zeus’ midrange performance. 

Vocals have a nice texture to them and have plenty of detail. Both male and female vocals performed well in my test tracks. Female vocals, in particular, are not very peaky, even for brighter sounding songs. 

Again, the positioning is a bit different from what I am used to. However, they blend nicely to the rest of the mix which, again, creates that enjoyable listening experience. 

The only possible critique that I have for the mids is the slight bump in the lower mids. This area can sound a bit warm, which some may interpret to be muddy. However, I do not mind that, and it can easily be fixed via EQ.  

Highs 

The highs of the HarmonicDyne Zeus are also very well executed. They extend very well but have excellent control to prevent any harsh spikes. You may find some songs that can bring out some peaks in the highs but this does not happen all the time. 

Overall, I find the highs to be similar to the approach of the HD6XX headphones. They are fairly laid back and relaxed but have enough detail in elements such as the cymbals to help bring the listening experience to life. 

Comparisons 

Sennheiser HD660S

The closest competitor to the HarmonicDyne Zeus is the Sennheiser HD6XX series. And my favorite member of the HD6XX family is the latest revision, the Sennheiser HD660S

While there is a pretty significant price gap between these two models, most of the HD660S points apply to the other HD6Xx models. And the fact that I am able to draw these comparisons makes things very interesting. 

The Sennheiser HD660S clearly edges out the HarmonicDyne Zeus when it comes to the mids. Very few headphones can beat the HD660S’ vocal performance so this does not come as a surprise. 

The HD660S has a more focused sound while the Zeus’ mids were a bit more distant and less detailed. And while vocals on the Zeus blend well in the overall mix, the HD660S takes vocals to the center stage and presents them with authority. 

But with that said, the HD660S and the HD6XX series as a whole have some well-known weaknesses. These include the bass and the soundstage. These are areas where the Zeus beats the HD660S. 

I find the Zeus’ bass to be a lot better both in terms of quantity and quality. They punch harder and are able to achieve a fuller sound compared to the HD660S. 

The soundstage of the Zeus is also significantly wider. It manages to achieve this without sounding artificial. The imaging is also on par to the HD660S which is very impressive considering the HD660S is well known for its accurate imaging. 

The highs on both the Zeus and the HD660S are laid back and smooth. The HD660S has a slight edge with smoother and more detailed highs, but both are very close. 

Overall, I would still consider the HD660S as the better option for professional applications such as music production since they have a more accurate sound. However, the Zeus is a great companion or alternative if you are looking for a more fun sound with deeper bass and more soundstage. 

Verdict 

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The HarmonicDyne Zeus was a very pleasant surprise. I never expected a headphone from a newer company to be very competitive with the established headphones in terms of sound quality. It fares very well against my Sennheiser HD660S and is certainly up there when it comes to technical performance. 

Its enjoyable sound signature is what has captivated me and is the reason why it will be staying with me long after I finish this review. It serves as the perfect companion to critical listening or studio pairs. And since it can handle gaming very well, you have a well rounded headphone that can do almost anything.  

The Zeus also has a very good value proposition. You get a very solid flight case, a nicely made cable, solid adapters, and an aesthetically pleasing and well built headphone. These do not come with most headphones and would cost a significant amount if you wanted to buy them from third-party brands. 

Overall, the HarmonicDyne Zeus is an easy recommendation for those looking for a fun-sounding headphone that does not compromise on the detail retrieval and technical capability.  

Specifications 

  • Type: Wired Headphones
  • Drivers: Φ50mm Beryllium Dynamic
  • Acoustic Architecture: Open back
  • Input Impedance: 64Ω
  • SPL: 100+3dB
  • THD: ≤0.2% ( 1000 Hz, 254 mW)
  • Cables: OCC cable, 150cm
  • Ear-cups: Walnut wood
  • Ear-pads: Nano velvet
  • Product Dimensions: 200mm*180mm*100mm
  • Product Weight: about 380g

Albums Used For Testing 

  • Milet – Who I am 
  • Babymetal – Legend Metal Galaxy 
  • Mamamoo – Travel
  • Periphery- Periphery 3 and 4
  • Blackpink – The Album 
  • Final Fantasy VII Acoustic Arrangements 
  • Square Enix Jazz- Final Fantasy VII At Billboard Live Tokyo
  • Sawano Hiroyuki – Best of Vocal Works
  • Yorushika – Plagiarism 
  • Intervals – Circadian

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