Review: HarmonicDyne Poseidon Headphones – Brother of Zeus

The Poseidon just hanging out.
The Poseidon just hanging out.

Is HarmonicDyne delivering a new god-tier listening experience or did Zeus just get all wet?

Thank you to Linsoul for providing the HarmonicDyne Poseidon for review purposes. It is now available on Kickstarter.

To date, HarmonicDyne has released 3 models of full-sized headphones. Although, it’s arguable that they’ve only made one pair and two revisions. First came the Helios, featuring a distinctive plastic and aluminum band with wood inserts, flawless laser-cut wooden cups, and stainless-steel grills.

Then came the Zeus, featuring all those same attributes, plus the addition of beryllium drivers, bigger and better ear pads, and a swanky hard storage case.

Now meet the Poseidon. Same band, same cups, same grills? But no! The metal parts are all black, rather than silver, and the dark walnut wood has been changed to a lighter shade of maple. The case has returned, albeit with a color change, and the drivers are now “custom 50mm nickel diaphragm dynamic drivers.”

The color change is a good decision.
Bottom Line

Poseidon has much in common with his brother. The change of driver material coating has subtly changed things for the better. The Poseidon are both punchier and airier while maintaining that deliciously smooth character delivered by the Zeus. A side-grade perhaps, but in this case, a worthwhile one. I now feel I was perhaps too hard on the Zeus in my earlier review. Even though the Poseidon offer much of the same, I find I appreciate them more.

What We Like
  • Smooth and natural sound character
  • Punchier and more airy than the Zeus
  • Black powder-coating looks terrific
  • Serious storage case
  • Good balanced cable and single-ended adapter included
  • Comfortable and non-fatiguing for long listening sessions
What We Don't Like
  • Headband quality doesn’t match the flawless earcups
  • Lighter colored wood won’t be loved by all
  • Same build quality as the less-expensive Helios
The color change is a good decision.
The color change is a good decision.
Another thing that got ‘UP’-graded along the way was the price. The Helios retailed between USD$150-$200 while the Zeus are nearly double that cost. The pair of Poseidon that I have is a pre-release set and the retail price has not yet been revealed.

Frankly, my feelings about the Helios were merely lukewarm, and while the Zeus offered a significant upgrade (especially in sound quality), I questioned their value proposition. The Zeus are twice the cost but feature almost identical build quality to their sibling. I wondered how much we were paying for the fancy new cable and case, in addition to the more meaningful driver and earpad change.

Are the Poseidon a real upgrade to the Zeus or merely a side-grade? Other than the change to nickel-coated drivers, the changes appear mainly cosmetic. While I can’t answer if the Poseidon will also have a price bump, does this shared build quality and materials better fit a sub-USD$200 pair of headphones?

The water is warm. Dive in and let’s find out together.

Company Overview

In their own words, “Linsoul was founded in 2016 by Crazy HiFi team with the intention of providing world class customer service to the audiophile and music loving communities.” They curate audio products from Chinese Hi-Fi (Chi-Fi) companies and provide customization services including custom-molded IEMs.

OUR STORY

The founder of Linsoul realized that Hifi music listening should be inspirational and modern stylish. It can be combined with sound quality and stylish to express your music style.

MISSION

To deliver Hi-Fi products that surpass the norm in terms of both Sound Quality and visual intrigue.” – Linsoul

I think it is important to note that the Story and Mission statements of Linsoul declare that they do not solely strive for products with the highest sound quality. Rather they refer to a combination of sound quality and visual style. It seems the aesthetic appeal of their products is as important as how they sound.

Technical Specifications

  • Form: Open-back, over-ear
  • Drivers: 50mm nickel-coated diaphragm dynamic drivers
  • Impedance (Ohm): 64 Ohm
  • Sensitivity (dB): 103 ±[email protected] Hz
  • Frequency Response (Hz): 10 Hz – 40 kHz
  • Removable Cable: Y – 2m
  • Source Jack: 4-pin XLR, 6.35 TRS adapter included
  • Cup/Shell Jack: 2×3.5mm
  • Mic: N
  • Weight (g): 380g without cable
  • Materials: Plastic, aluminum, stainless steel, maple wood
Nothing says self-importance quite like a case like this.
Nothing says self-importance quite like a case like this.

Packaging

Unboxing the Poseidon gives a real glimpse at the experience of opening a TOTL product. Unlike cutting tape seams on a cardboard box, unsnapping the buckles on the hard case and lifting the lid never fails to impress. Inside you are greeted with laser cut foam nestling the headphones, an individual serial number plate, case keys, and a storage area containing the cable and soft bag.

The layout, fit, and finish are impeccable.

In the box

  • Poseidon headphones
  • Hard locking travel case
  • 2m Balanced cable (2×3.5mm to 4-pin XLR)
  • Single-Ended adapter cable (4-pin XLR to 6.35mm TRS)
  • Cloth protective bag
  • Manual
Open it up and it looks so good!
Open it up and it looks so good!

The case and accessories are all an upgrade over those included with the Zeus. While the case appears to be essentially identical in construction, the new two-tone black and grey scheme elevates the aesthetics. Even the interior foam and quality of the cutouts are noticeably improved.

Cable

I really like the new Poseidon cable. It consists of two strands covered in fabric from the 4-pin XLR plug to the y-split. It’s plain black rubber from the split to the dual 3.5mm plugs. Also included is a short female 4-pin XLR jack to 6.35mm plug adapter for single-ended use.

This is not intended to be a portable cable, so plan on purchasing a shorter replacement if you plan on going out and about with the Poseidon.
The cable and adapter are welcome additions.
The cable and adapter are welcome additions.

Compared to the Zeus cable, the new one is far more supple and flexible, and I much prefer it. The mega-buck Focal Stellia headphones arrived this week as well for review, and interestingly, the Poseidon cable shares much in common with the Focal one.

Both are long, rubberized, fabric wrapped, dual-wire cords, terminated in 4-pin XLR and dual 3.5mm. The most appreciable difference is Focal’s use of industry-standard Neutrik 4-pin connectors, rather than the cheaper-seeming, unbranded versions included on the HamonicDyne cable.

I greatly appreciate the included single-ended adapter. Focal doesn’t include one, although they do include a shorter 3.5mm cable for portable use.

Design

As noted, the Poseidon share much of the same materials and design as their two siblings. Again, the precisely crafted wooden cups are the standout feature, while the headband doesn’t seem quite the same level of construction quality.

A major positive is the change to powder-coating the metal bits black. This removes the slight visual mismatch between the aluminum parts and the steel grills. I’m less sure about the switch from walnut to maple. Clearly, HarmonicDyne is going for a contrasting color scheme, but I prefer the looks of the darker wood. The thin wooden veneer on the headband visually stands out a little too much.

I'm not quite sure what I think of the wooden veneer on the side of the band.
I’m not quite sure what I think of the wooden veneer on the side of the band.
I’m seriously considering how difficult it will be to liberate the darker wood parts from the Helios and incorporate them into the Poseidon. A black/walnut model is very likely in the works from HarmonicDyne, but I could be the first to have an all dark version, that I’ll hereby call the ‘Hades’.

Comfort

The construction of the headband is more suitable for a sub-$200 model such as the Helios. While it contains a steel core, and HarmonicDyne claims “the headband itself is made with several layers of resonant damping polymers,” in practice it feels a bit too plastic and creaky. I’ve run across reports in online forums of Zeus headband failures.

I'm typically the recipient of serial number 14. I've moved up in the world! The plush ear pads and padded band are very comfortable.
I’m typically the recipient of serial number 14. I’ve moved up in the world!
The plush ear pads and padded band are very comfortable.

On the positive side, the headband has many adjustment positions and is well padded and comfortable to wear. Paired with what appear to be the same soft, deep, “nanometer suede” ear pads that debuted on the Zeus, the Poseidon can be worn very comfortably for hours. They remain remarkably cool and hot-spot-free.

Internals

Cosmetic changes aside, what most differentiates the Poseidon is the change of driver material. Lately, it seems Beryllium-coated drivers are all the rage, so it’s interesting (and innovative) to see a new coating material being hyped.

Poseidon exploded diagram. (From: linsoul.com)
Poseidon exploded diagram. (From: linsoul.com)

“While beryllium has been hailed as the king of diaphragm materials so far, the molecular composition of nickel proves to be a much superior metal for the conductance of sound. With four times the density and more than double the tensile strength of beryllium, purified nickel is a much stiffer and responsive diaphragm material, allowing greater clarity and articulation with reduced distortion in the low frequencies.

Most nickel-based drivers used in audio products are nickel-alloys, meaning they have been mixed with other inferior metals to reduce production costs. However, the Poseidon utilizes only the purest laboratory-grade nickel, producing an extremely well-controlled frequency response with unparalleled technical performance.” – Linsoul

The new driver looks much the same as the old.
The new driver looks much the same as the old.

There’s no question that the change of driver material and ear pads made a significant improvement in the sound of the Zeus from the Helios. Linsoul apparently believes the change to a nickel coating will do the same for the Poseidon.

HarmonicDyne driver comparison

HeadphonesHeliosZeusPoseidon
Driver50mm German-engineered, custom composite dynamic drivers50mm Beryllium-coated dynamic drivers50mm Nickel-coated dynamic drivers
Impedance16 Ohms64 Ohms64 Ohms
THD≤0.2% (1000 Hz, 254mW)≤0.2% (1000 Hz, 1mW)
Frequency Response10Hz – 40kHz10Hz – 40kHz10Hz – 40kHz

HarmonicDyne Poseidon Sound

The bulk of my listening was done with the Burson Conductor 3 Reference desktop DAC/amp and an absolutely random playlist served up by the whims of Roon.

HarmonicDyne claims that the “new nickel diaphragm driver further enhances the resolution beyond high-fidelity standards, bringing out unheard details across the entire frequency spectrum.” With a claimed frequency response of 10Hz to 40kHz and open-backed design, HarmonicDyne boasts that the Poseidon have “a surreal airy character and lifelike soundstage” that is “both accurate and musical.”

The Poseidon sound great plugged into a Burson Conductor amplifier.
The Poseidon sound great plugged into a Burson Conductor amplifier.

The Poseidon continue to feature an angled driver positioned in front of the ear canal and angled backward – a design used by other manufacturers including Stax, Beyerdynamic, Sennheiser, and Ultrasone. This is done to better simulate the natural interaction of sound waves and the ear structure, and to improve imaging, soundstage, and a sense of space. As a result, the Poseidon give a convincing impression of an open and spacious sound field.

While the Zeus sound was a major change from the Helios, the differences between the Zeus and the Poseidon are far subtler. Measurements indicate that the sub-bass response of the Zeus is boosted, while there is a bit of a bump in the Poseidon mid-bass range. The rest of the frequency spectrum is fairly similar with a little bit more treble energy evident in the Poseidon.

To be honest, I like the Poseidon sound more than the Zeus. They exhibit very competent resolution, and voices and instruments are presented with natural and real-feeling tonality. They maintain the neutral timbre and smooth texture of the Zeus while adding a helping of mid-bass punch and a touch more upper air. The overall impression is laid-back rather than forward or in-your-face, but the Poseidon deliver enough dynamics and sweetness to avoid feeling tame or boring.

Comparison of the frequency response measurements of the HarmonicDyne Helios (blue), Zeus (brown), and Poseidon (green) captured by a miniDSP EARS device.
Comparison of the frequency response measurements of the HarmonicDyne Helios (blue), Zeus (brown), and Poseidon (green) captured by a miniDSP EARS device.

Bass

“From the previous Zeus model, the low-end has been further extended, providing a greater sub-bass impact beginning from 10Hz. The resulting experience is a true subwoofer rumble that is both powerful and quick, thanks to the stiffness of the nickel diaphragm driver.” – Linsoul

This isn’t exactly what I hear, nor what I measure. I do find the Poseidon deliver more mid-bass snap, although at the expense of some of the subterranean bass depth of the Zeus. Combined with a fast and tight response, the Poseidon are amped up a bit in energy, and all that punchiness adds up to a fun sound.

Midrange

“The responsiveness of the new driver also means a higher caliber of clarity and detail retrieval in the mid-range and treble. The Poseidon is acoustically poised to playback your music at the highest degree of resolution possible.” – Linsoul

The Poseidon are a mildly v-shaped set of headphones and the midrange sits a bit back in the mix, although what is there is very well done. I greatly enjoy the smooth midrange signature, and voices and instruments retain a fairly neutral and natural quality. Again, the Poseidon are a huge improvement over the unnaturally forward sound signature of the Helios and sound quite similar to the Zeus.

Treble

Both the Zeus and Poseidon are warmer and darker sounding than the Helios, however, the change in drivers seems to have added just a little more air and sparkle to the Poseidon. It’s a change for the better, IMO, and the smooth signature hasn’t been lost, just subtly improved upon.

Treble-heads should likely look elsewhere, but those who crave a warm and relaxed sound signature will likely be delighted with the Poseidon.

The new grill design and black color looks great!
The new grill design and black color looks great!

Where to Buy

Conclusion

Brother to Zeus and Hades, Poseidon is the god of the sea, earthquakes, and horses. While even I struggle to craft a relevant pun that includes all those elements, the sibling reference is evident. Featuring many of the same parts and construction, but in a new colorway, the lineage is evident. Poseidon has much in common with his brother.

The change of driver material coating has subtly changed things for the better. The Poseidon are both punchier and airier while maintaining that deliciously smooth character delivered by the Zeus. A side-grade perhaps, but in this case, a worthwhile one.

I now feel I was perhaps too hard on the Zeus in my earlier review. Even though the Poseidon offer much of the same, I find I appreciate them more. I couldn’t distance myself from the flaws of the original Helios, and I got hung up on the thought of paying twice as much for the Zeus, rather than truly judging them on their own merits.

It seems that time has created space for me to fairly assess things, and I’m far more impressed with the Poseidon than I expected I’d be.

Now if HarmonicDyne improved the band to match the quality of the cups and gimbals, and perhaps married the walnut and black designs, the inevitable next god-named model could truly rival, and perhaps best, far more expensive high-end headphones.

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