Being a god of sky and thunder, protector and ruler of the heavens all sounds pretty cool. They would all be epithets to aspire to if you were a relatively new brand producing headphones for demanding mobs of enthusiasts. In this review, I’m checking out the HarmonicDyne Zeus headphones. The Zeus is a full-size open-back headphone with 50mm beryllium dynamic drivers. It’s the second product from the brand, following their debut model which was the Helios.

Disclaimer: This sample was provided for the purpose of an honest review. All observations and opinions here are my own based on my experience with the product.

HarmonicDyne Zeus

Specifications

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

Packaging & Accessories

If HarmonicDyne was trying to make a good first impression with Zeus, they really outdid themselves. The headphones come in a large metal-reinforced plastic hard case and lockable latches (keys included).

Inside the box, the headphones are secured in a soft foam insert. They’re very well protected so if you wanted to travel with the Zeus, you could rest assured that they will reach their destination unscathed. Apart from the headphones, you get an ultra-high purity copper balanced cable, a 4.4mm balanced to 3.5mm single-ended adapter plus a 3.5mm single-ended to 6.35mm single-ended adapter, a user manual and two keys for the case locks.

Design

After the excellent unboxing experience, I had high expectations for the headphone’s build quality and Zeus didn’t disappoint. The spring steel headband is encased in a hard plastic enclosure with generous padding on the underside. The rest of the frame is metal, giving Zeus a reassuring sturdiness and promise of longevity.

Like the previous Helios model, the HarmonicDyne Zeus has walnut wood earcups that match the wood panels on the headband. The earcups are capped with an intricately crafted metal plate that really gives them a unique and striking aesthetic.

Each earcup is fitted with a 3.5mm socket so it’s easy to upgrade or replace the cable if needed. They also rotate 180 degrees so you can lay them flat on a desk or around your neck easily. The stock earpads are thick and have a nano velvet cover making them super plush and comfortable.

Weighing in at 380g, Zeus is somewhat heavy but I find the plush earpads, moderate clamp force and padded headband all work together to provide a comfortable fit. Being an open-back design means there’s a lot of noise leak and practically no noise isolation so Zeus is better suited to quiet, controlled environments.

Cable

The included cable is an ultra-high purity OCC copper wire. It has a braided fabric sheath below the Y-split and transparent TPU insulation above the split. It has excellent strain relief from top to bottom and aluminium components.

This is a thick and rather stiff (insert “That’s what she said” joke here) cable which is bound to upset some precious flowers out there. But I love it: it feels deliciously robust and there is no microphonics whatsoever.

The cable terminates in a straight 4.4mm balanced plug. But just in case you don’t have an amplifier or DAC with a 4.4mm jack, you can use the included adapters. If you want to use a 6.35mm phone jack, it’s a little amusing as it requires both adapters attached.

You end up with a lengthy Frankenstein contraption that’s really long and rather cumbersome but I kinda like its quirkiness. Generally, it’s a high-quality cable although the handling could be better.

Sound

Gear used for testing includes:

• Singxer SDA-2 (6.35mm single-ended)
• iFi Audio Micro iDSD Signature (4.4mm balanced)
• iPhone with Earmen Sparrow (3.5mm single-ended)

The HarmonicDyne Zeus has a pleasant, warm tonality that has an unusual mix of thick notes and fast transients. Despite being an open-back set, Zeus has many of the characteristics found in closed-back headphones, such as strong imaging, full-bodied bass and soundstage stability.

Its musical character is defined by a warm low end, in particular the boosted mid-bass. This tuning isn’t likely to appease those who are looking for a highly technical, bright or detailed presentation. But if someone wanted a musical, smooth and warm sound then this would likely be right up their alley.

Bass

The bass plays a major role in Zeus’ tonality, especially the mid and upper-bass. It lends a lot of warmth to the lower midrange and gives the overall presentation a sense of body and thickness. Where I find Zeus really surprising is how it manages its note thickness with nimbleness.

So although it does sound warm and have a large note size, it has the transient speed to pull it off without getting bloated. The bass has good extension and creates a satisfying light rumble but the Zeus doesn’t have basshead level lows.

Katatonia’s “Leech” has a slamming, punchy kick drum. Listening to this track on the Zeus, the bass sounds lively and slightly softened but in no way overbearing. So although it has a warm signature, Zeus’ bass still maintains a pleasing tonal balance.

Mids

The midrange inherits significant warmth and some colour from the bass. Fortunately, there’s still adequate clarity so vocals and instruments don’t sound smeared or dull. Zeus’ tonality lends itself really well to male vocals and string instruments. Female vocals and electric guitars don’t have the same lustre but they’re textured yet inoffensive.

The midrange resolution is pretty impressive. This is a result of the driver’s fast transients and lack of resonance, courtesy of the open-back design. Even on complex tracks, Zeus holds its own and flaunts its instrument separation, keeping the sound clean and free of congestion.

Treble

The treble is somewhat softened and rounded but still crisp. It’s inoffensive and perfect for the treble-sensitive. Some micro-details are lost in Zeus’ overarching warmth due to the laid back nature of the treble. But for the most part, the high frequencies sound natural and reasonably airy.

Treble lovers and those looking for extreme precision aren’t likely to find their perfect headphones here. But let’s be honest, those people probably stopped reading at “warm”. The Zeus’ high end has just enough bite to keep things lively without ever sounding glary or harsh.

Soundstage

For an open-back headphone, the size of the soundstage is somewhat average. It’s a little narrow, probably because of the subdued treble but it has excellent depth. Where Zeus really surprises is in the quality of its imaging which is very good for an open phone. In this sense, it feels more akin to what you get with a closed-back set. But thanks to the resolution and control, instrument separation is above-average.

Comparisons

Hifiman Sundara ($350)

The Hifiman Sundara is an open-back headphone with planar magnetic drivers. It has been my benchmark for headphones in this price range for some time and that hasn’t changed. The Sundara has a lighter, more balanced tonality with a leaner note size.

Sundara has better bass definition with cleaner leading edges. The planar drivers have exceptional transients which keep things very fast and tidy compared to Zeus’ thicker and more melodious bass. The Sundara’s midrange is leaner, cleaner and has more upper midrange lift. The Zeus’ in comparison tilts towards the lower midrange with a thicker, meatier sound.

At the top end, Sundara’s treble sounds more precise and airier but it is still non-fatiguing. It’s relatively laid back but sounds clearer because of the leaner bass and midrange sections which allow it more room to breathe.

Soundstage is larger on the Sundara. It’s wider and the stage is positioned further back compared to the Zeus’ more intimate stage. Detail retrieval is superior on the Sundara too and it’s able to reveal sounds that are masked on the Zeus.

Sivga Phoenix ($299)

The Sivga Phoenix is another open-back dynamic driver headphone. It’s smaller and more lightweight compared to the Zeus. Both headphones have very good build quality. The Phoenix has a warm tonality but it sounds noticeably brighter than the Zeus because of its boosted upper midrange.

The Phoenix has more sub-bass reach and has more physical rumble. Its mid-bass is also more pronounced, relative to the midrange which sounds more recessed compared to the Zeus. Male vocals are leaner but less intimate on the Phoneix while female vocals and electric guitars are lifted.

Treble is starker on the Phoenix, especially the lower treble which is more forward, giving the Phoenix its V-shaped signature. The Zeus sounds much smoother and less aggressive in comparison. When it comes to resolution, Zeus comes out ahead with more space between elements and superior instrument separation. The soundstage is smaller and more intimate compared to the Zeus.

Conclusion