General Information


Apos Audio and Kennerton collaborated to create this $499 open-back headphone. Since there are so many details about it, I suggest you follow the "full story" from Apos' website: "Explore the Caspian’s story, measurements, and creation process."

Official Page:

Product highlights

  • Fun-sounding, non-fatiguing for marathon sessions
  • 50mm dynamic driver
  • Open-back
  • All-natural oak earcups sourced from the North Caucasus mountains
  • Inch-deep sheepskin ear pads with acoustic memory-foam inner filling.
  • Stainless steel yoke and headband
  • Natural leather headband pad for all-day comfort
  • Aluminum alloy grille
  • Graphene-coated multilayered composite membrane with variable thickness
  • CCAW coil (aluminum core coated with oxygen-free copper)
  • Internal litz wiring


  • Driver: Graphene-coated multilayered composite
  • Driver unit: 50mm
  • Frequency response: 5-45,000Hz
  • Sensitivity: 115dB
  • Impedance: 33Ω
  • Maximum input power: 500mW
  • Ear cup outer material: Natural sheepskin leather
  • Ear cup inner material: Acoustic memory foam
  • Thickness of pads: 1” (27mm)
  • External dimensions of pads: 4.5” x 3.4” (115mm x 88mm)
  • Height and width of ear pad opening: 3” x 1.7” (77mm x 45mm)
  • Grille material: aluminum alloy
  • Headband materials: stainless steel, natural leather outer lining, bio-leather inner lining, polyurethane foam insert
  • Yoke material: stainless steel
  • Weight: 13.3oz (378g)

What’s included

  • Apos Caspian headphone
  • Leather carrying bag
  • Stock headphone cable (single-ended 6.35mm termination)


Latest reviews


Headphoneus Supremus
What if someone got to make their dream headphone?
Pros: +Unique tuning
+Adds color to everything
+Strong bass and lower mids
+High resolution, low mud
+Handsome design and wood cups
+Low amplification power requirements
+Musical synergy, even with an otherwise clinical DAC/amp stack
+Handsome stained wood
+Metal and leather
Cons: -Adds its colored signature to everything
-Not ideal for people who prioritize airy sparkling sound, or strictly neutral
-Wood, metal, and leather = Moderately heavy (ymmv)
-Sheepskin is a smooth leather, but still has the caveats of leather (ymmv)


Lets start with a food analogy. A dish like Fried Rice or American pizza is a lot like a Harmon curve tuned headphone: they are almost always welcome meals in any season, and they can accommodate most ingredients (music) you happen to have in the fridge and still taste good. A more unique flavor is a bigger risk, but at the right time they can really hit the spot: a summer pistachio ice cream, pumpkin spice latte in the fall, pork chops with a drizzle of bitter dark chocolate sauce and mint leaf garnish, or a pair of Apos Caspian headphones with rock, dubstep, EDM, or smoky, intimate club music. The Caspian won’t be all things for all people, but it is a passion project for people who want a heavy sound.

Disclosure: Apos Audio loaned me the Caspian with standard and optional balanced Flow cables at no cost to me, but they did not stipulate for a hype review, also I received no compensation and I have to send the headphones back to them.

Physical Attributes​

Evoking speakers and furniture, the dark stained wood and black leather upholstery of the Caspian have a design that would fit right in with a handsome bachelors pad. If you think a black leather & espresso wood couch sounds comfy, these are the headphone equivalent.

Timber and metal build “quality” come at a cost though: these are heavier than a resin or plastic based headphone from AKG or Sennheiser, or an on-ear portable headphone, but the weight is distributed ok. For people who prefer real leather pads, these seem to be the moisturized, soft, real sheepskin type, oval shaped and detachable with a similar kind of “slot” mount as a Beyerdynamic. The foam inside is a high density memory foam… but it doesn’t need massaged back into shape under the leather every time you wear it. So, I think people who like leather pads will find a lot to like here, and they will be easy to wipe clean, but I also find the typical leather & memory foam pitfalls: they retain heat really well, and eventually the leather feels “hard” against my head after about 45 minutes (YMMV, I’m really sensitive to this). The headband is evenly padded across the length; people with buzz cuts or thin hair may miss having a divot in the center to prevent a hotspot.
While I did most of my testing with the 4.4mm balanced output of my HiBy R6 Pro (a portable music player), I would say by physical traits this headphone is safely intended for home use. The black stock cable and the upgraded Flow red balanced cable have their “Y” joint about a foot and a half from the earcups: nice for flexibility as you turn your head or lean back, but also more easily caught on something when walking around (and more surface for microphonic rubbing noises, though the soft red woven wrap isn’t the most scratchy). It looks a bit bulky and feels a bit heavy so I wouldn’t expect people to walk outside with it (plus it’s open back, with no water proofing and only a fabric dust/hair protection layer on the inside of the earcup). Neither does the headphone fold flat, or make any other accommodations to coexist inside a backpack. The oval earcups only fit under the chin of longer necked people (like me!), and the cables exit the earcups at an angle so they rest forward of your shoulders (nice!) but that also means they stick up if the cups are laid back around your neck. However, the Caspian also comes with quite a nice cubical zippered case, with two zippered mesh pockets inside for accessories, wrapped in a smooth protein leather that looks classy, and I could certainly see someone taking this to an office or just using the case for storage.


Savory, heavy sound flavor with bass and lower mids emphasis.
It’s a colored sound, which has pros and cons, and will divide reception, but I don’t think that’s necessarily a bad thing. With low-end extension and emphasis almost unheard of in open headphones, the Caspian kicks serious bass! This fundamental grounding keeps breathy female vocals from soaring in EDM like “Delicate Weapon” by Grimes & Lizzy Wizzy
, but Drums ‘n Bass (DnB) or dubstep will have their beats and oceanic bass waves pressed into the spotlight. I also immediately thought of (and looked up) Cowboy Junkie’s Trinity Sessions album… a famous “in situ” recording among audiophiles, but I felt like the harmonica was mic’ed a bit hot in the recording and can especially sound shrill on the otherwise wonderful finale “Postcard Blues.” Well, the Caspian really plays to the strengths of this song: a synergy of honey with Margot’s vocals, richness in the guitar and other instruments’ fundamentals as each are added, and the harmonica is still loud, but more rounded, less shrill, sweeter. Checking out the perennial bass test track, Angel by Massive Attack, takes the ominous bass overtones to full threat level, with Andy Horance’s velvety and moist high vocals emerging from the shadows. I also asked my mother in law (lets say she’s more “mainstream” in her audiophile experience level) to have a listen, and she remarked how clear it sounded to her. In some ways, this tuning is like the designers wanted to add more bass to an HD 650, though they made their own thing in the end.

However, I believe the tuning from Sandu Vitalie and Kennerton’s design considerations have managed to avoid a muddy mess. Apos published their own frequency response graph on their product page (I copied their “raw” graph here), and while it‘s plain to see that the sub bass has about 8-9 dB more intensity than the 1 kHz mids, and substantial dips in the upper mids/treble frequencies, the end result still has plenty of detail, and the highs are present despite being laid back. Psychoacoustically, our brains are more apt to notice peaks than we are dips, so sure the graph looks a little uneven, but it also has some of the tailored look of what a music producer might do when mastering their music to reduce fatigue without impacting presence much. What this all boils down to is the headphone has an intentional tuning that will not be a jack of all trades, but do some music (or fit some tastes) particularly well. And most people will be able to reach the peak of the “amplifier scaling” easily with this headphone… with low impedance and high sensitivity in a rating that looks like they belong to a small portable headphone, you don’t need much power to hear what the designers intended (an Apple dongle would be fine!), though the headphone has enough resolution that it pays to have a signal chain that has minimal distortion. For audiophiles who prefer a Topping or SMSL amp that measures very low distortion but perhaps sounds a little clinical, the Caspian might offer a great synergy that brings some emotion and art back into the music. For me, the headphone seems to beg being played a bit loud, where it had admirably low distortion, but physically still resulted in me wanting a break after an hour… the design intent was to be low fatigue, and your mileage may vary from mine!

The Caspian also features other design elements to prevent masking of detail. Aluminum is not as electrically conductive as copper, however it is a fraction of the weight, therefore much less mass, thus the copper-plated aluminum voice coils attached to the driver membrane have less inertia than they would if the wiring was pure copper. The driver is rather large, and offers great air displacement for the bass. I’m not entirely sure if humanity has mastered graphene-coated drivers yet to take full advantage of the material (maybe if the polymer membrane was infused with graphene rather than just two attached layers…) but I’m not an engineer or an expert, and perhaps this graphene plus the lower mass voice coils have assisted in the audible result of a low distortion driver with quicker decay than I would expect from this size driver or this much bass. Kennerton surely put a lot of technology and inspiration into the design!

As I have had this demo unit for several months (Sorry Apos), I’ve saved ten songs that I’ve come across on shuffle that play to the strengths of the headphone’s coloration:

Postcard Blues - Cowboy Junkies, acoustic country + jazz vocals
A Mountain, A Peak - Bill Riccini, alt folk
Ohh La La - The Ditty Bops, folk female vocals, brings up some impact of the backing instruments
On The Beach - Alamo Race Track, Alt rock, vocals sound a bit softened in a pleasant lo-fi way, but the fundamentals of all the instruments are enriched
Make Up Sex - Machine Gun Kelly & black ear, Explicit, pop, glosses over some of the “hot” distorted instruments and allow the listener to focus on vocals and drum beats, decent Pop headphone
The First Morning of the World - by Beautiful Chorus, Maxim Emelyanychev, Il Pomo d’Oro & Joyce DiDonato, an English operatic Classical piece, doesn’t transport the listener to the venue, but presents a comfortable and powerful experience, showcasing a decent ability of the Caspian to play tracks with high dynamic range and resolution.
World’s Forgotten Boy - Billy Idol, 80’s Rock, the reverb-soaked effects don’t transport the listener to a concert venue with the Caspian’s more intimate soundstage, but the grunt and emotion definitely come through and bring concert-excitement home.

Who is it cool for?​

The Caspian is a beautiful lie. It’s not a studio-neutral headphone that presents the truth and nothing but the truth (so help me!), however it is a rocking headphone that focuses on the emotional experience. For people that use wireless earbuds or smartphone speakerphones, or have a pair of closed-back ANC headphones for on the go use, this headphone will appeal to bassheads and be a great complimentary headphone to come home to. They may find themselves surprised that an open backed headphone can be a basshead headphone, and surprised that a basshead headphone can also sound fairly clear. I think it would also be fun for someone who only has an hour or less for each session of music fun, and wants to maximize their listening session.



Headphoneus Supremus
Apos new headphone - the Prince Caspian?
Pros: Great build quality, mini-XLR at cups gives plenty of cable options, Fun signature for pop, rock, edm, and hip-hop
Cons: no 3.5mm cable provided, warmer than some and not reference neutral.
Can the $499 Apos Caspian Headphones deliver the sonic goods or are they too sweet for their own good?

Apos Caspian Headphone

It takes a certain kind of craziness to want to introduce a new line of headphones in 2021. On top of a super conjested market with minimal returns (Ask the folks at Sennheiser who sold off their consumer headphones division last year if it’s all strudel and coffee in that regard), You have the shortages of parts due to the pandemic, and embargoes of some parts due to political pressures.

Apos Audio’s primary focus is the retail side of the business but that hasn’t stopped them from collaborating with headphone manufacturers and creating products like the Apos Caspian Headphones which we previewed in August 2021. Getting into the headphone market right now is fraught with all kinds of risk and after a recent conversation with one of the brands that has benefited enormously from the exponential growth of the market and sold thousands of DACs and headphone amplifiers in the process — it’s not something that they have contemplated for even one second. Just because you can, doesn’t always mean that you should.

On the other hand, the margins can be pretty good for boutique headphone manufacturers, but are very small when it comes to the larger mass market products, and finding a way to distinguish your new product in an ocean of headphones is very difficult. Brands like Audeze realized this a few years ago and started developing other products utilizing their technology for other markets like the medical world and office conference speaker systems.

The market for $4,000 headphones is remarkably small and it’s why brands like Grado Labs who sell thousands of high-end headphones every year has kept its focus on affordable models and its very successful phono cartridge business which pays the bills every month.

Apos Caspian Headphone Vertical Side

From Russia with Love?​

In order to mitigate the risks and improve their chances of success, Apos Audio partnered with Sandu Vitalie of Soundnews to help tune their new headphone, and with Kennerton Audio; who are based in Russia for help with the design and construction.

Kennerton Audio’s own line of headphones runs from the Jord ($350) up to the Rognir (read our review) and Thror ($3500) with several stops along the Trans-Siberian Railway giving them some level of expertise when designing headphones for the upper end of the market. The Rognir is one of the most impressive products in the ultra high-end headphone category and should be considered with the best from Meze Audio, Audeze, and Dan Clark Audio.

Sandu founded Soundnews and has been listening and writing about audio gear for quite some time now and had some definite ideas about what he wanted in a headphone; Apos also had a very specific price point that they wanted to target and the reached out to Kennerton. From this collaboration, we ended up with the Apos Caspian Headphone that is under review this week.

I’m sure some will raise an eyebrow at the idea that a publication is getting into the “manufacturing” side of the business but how is that any different than publications like Gear Patrol who do product collaborations with Huckberry and a lot of outdoor product manufacturers?

Apos Caspian Headphone Kit with Carrying Case and Cables

Nobody forces you to buy anything and you are being informed about the conflict in advance.

The Skinny​

Those familiar with the Kennerton family of headphones will recognize some of the features from their other models fairly quickly. The headband is pure Gallahorn GH, the cups and cable jacks are from the Vali, and the wood is similar to the Magni or M12 Dusk.

The cable and case are also typical of Kennerton offerings. The areas where the Apos Caspian differs from most of the Kennerton line are the driver which is unique to the Caspian and the cup design which shares elements of the Vali and Magni, but is not a duplicate of either.

The ear pads are hand-sewn leather and again similar to other Kennerton models and one of the better made memory foam pads available in my personal experience.

Apos Caspian Headphone Outer Hinge

For those less familiar with the Kennerton line, the Caspian has a steel headband with a padded leather wrap and stamped gimbals with adjustments similar to those used by Beyerdynamic or Sennheiser.

The ear cups are aged oak with a large grille finished with the Apos logo in matte black that matches the gimbal/headband. The connectors are 3-pin mini-XLRs on each cup with a slight forward angle.

Apos Caspian Headphone Gimbal

Overall, the Apos Caspian has a dark wood and flat metal aesthetic that gives it a very businesslike appearance. The 380 gram weight puts it near the middle of the pack; the HiFiMN HD6xx weighs closer to 200 grams and the HiFiMAN HE6 tip the scale at nearly 700 grams.

The Kishkas​

Internally, the Apos Caspian uses a 50mm dynamic driver with a graphene coated low-mass diaphragm. The driver is then mechanically decoupled from the frame to help lower distortion; it has been tuned to deliver a polite sonic signature with some intentional filtering of the top end between 2 kHz and 7 kHz to reduce listener fatigue.
Can you drive these with your iPhone or a Dongle DAC?

The nominal impedance is listed as 33 ohms with a sensitivity of 115dB/mW. My measurements showed an impedance of 37 ohms at 1 kHz and a sensitivity of 116dB/mW at the same frequency (±3dB).

This puts the Caspian in the class of headphones that can easily be driven by a Dongle DAC or tablet; but I would add that it doesn’t require one from a power perspective.

The Caspian will scale some qualitatively with better sources but it simply does not need the additional power most amps provide.

Flow Cable

Apos Flow cable (XLR to mini-XLR) costs $100 extra I found it odd that a headphone that was designed to work using a Dongle DAC, phone, or tablet does not come with a cable compatible with any of them. The stock cable is a 6.35mm single ended cable and the Apos Flow cable that was provided as an upgrade is 4-pin XLR to mini-XLR for in home use and the other options for the Flow cable do not include a 3.5mm single ended jack.

The Caspian seems a bit schizophrenic as it is designed for use with portable source gear but neither the open back design nor cable options are particularly suitable for that use case. Luckily, mini-XLR to 3.5mm cables are not all that uncommon and I had more than one in my possession so I was able to test the Caspian using both desktop gear (Questyle CMA 15 and RME ADI-2) and portable gear (Kann Alpha, WM1A, and Dethonray DTR1).

The Sound of Music​

I had initially tried the Caspian with the RME ADI-2 using it as a DAC and the Xduoo TA-26 amplifier but found it to be a poor pairing as both the amp and headphone add warmth to every recording and the overall presentation became too thick and lacking in detail.

Moving to the ADI-2’s headphone output resulted in a a cleaner sound with a much higher level of transparency and detail; the Questyle CMA15 also performed similarly with good dynamics and without adding more colorations to a headphone that definitely requires some sunlight if you really want to hear what it can do.

Apos Caspian Headphone Driver Open

On the low end, the Caspian delivers good bass extension and impact without sacrificing clarity in the process. I have to say I’m impressed with the amount of bass impact the Apos Caspian delivers for an open-back design as it borders on “bass-head” territory which is usually an area where closed back designs rule.

The bass does roll-off somewhere in the lower 20Hz range; there is more than enough impact with music, movies, and video games and an ample amount of texture.
The mid-bass offers some degree of emphasis; I would not call the Caspian neutral sounding in this particular area but the overall levels of transparency and texture are not diminished by it. There is definitely some mid-bass bleed which is something that I expected considering how strong the deep bass is with almost every genre of music.

The lower midrange has good note weight and energy which definitely moves the Caspian outside the norm and away from the Harman target; it would be fair to describe the Caspian are quite linear sounding in this area and that’s a really important characteristic especially with orchestral and string quartet pieces.
The combination of strong bass response, midrange energy and resolution really brought a number of classical pieces to life; the dynamics on the “1812 Overture,” and “The Great Gate of Kiev” were impressively reproduced and I found that strings had excellent timbre and decay.
When a headphone makes strings really sound that natural, it’s hard not to notice and want to continue listening.

There is an upper midrange lift that brings female vocals forward in the mix and gives violin a nice upper range without becoming brittle or steely sounding.
Listening to rock guitar tracks highlighted a few things; the Apos Caspian can be very impressive in terms of its tonal balance and midrange resolution, but it also rounds off the edges which could lead some to think that rock music will sound slightly dull. I do wish there was a bit more detail here in that regard.

Moving from the upper midrange into the lower treble the tonal balance remains fairly balanced and there isn’t much a change with the presentation. Above 6 kHz, there is a degree of roll-off which prevents the Caspian from ever sounding bright; the trade-off is a lack of air or sparkle that robs cymbals of some of their energy to sound more realistic.

The Caspian does respond well to some EQ between 6-8 kHz and I felt that the headphone responded best overall with source equipment and headphone amplifiers that were on the more neutral side. Darker sounding sources will come across as quite dull and lacking in detail through these headphones.

Apos Caspian Headphone Front on stand

The tonal balance of the Caspian has a rather significant impact on the soundstage; there is more depth than width, but I felt that the warmer tonal balance created the impression that there was much less than was actually present.

Everything sounds quite natural; a small club or large auditorium are faithfully reproduced but the tonal balance diminishes what could be one of the Caspian’s best attributes.

Instrument separation is good in the upper registers but can have a small degree of overlap in the lower. Every instrument occupies its own space within the soundstage but it’s not as carved out as other headphones in the category and I did detect a small amount (tiny) of compression when listening to some very complex material.


Who exactly should consider the Apos Caspian Headphones? With a tuning that is rather warm and slightly thick, I would honestly suggest that it is better suited for headphone listeners that are using it with more neutral sounding or even bright source components or headphone amplifiers.

Is it for the Head-Fi folks who want to conduct a critical listening session every single time they put them on? Not really.
The cable choice is odd considering that its impedance and sensitivity rating make it almost ideal for portable source gear. I do think you will achieve better sound quality using a dedicated headphone amplifier and balanced cables if this is going to be a daily driver. The build quality is quite good and the overall attention to detail and finish is quite appropriate for the asking price.

Apos Caspian Headphone Connectors

But is it different enough from the other models in the Kennerton lineup to warrant a look if you already own their M12 or Magni headphones? Yes, it carves out its own niche within the Kennerton made models.

At $499, it faces a lot of competition from HiFiMAN, Sennheiser, and Meze Audio and others as well so where does it fit?

If you’re looking for a neutral or overly detailed sounding pair of headphones, the Caspian won’t be your cup of tea.

But for those of you looking for a very pleasing sounding pair of headphones for popular genres,, the Apos Caspian might be exactly what you’ve been searching for. The fact it is equally at home in the studio and on the road is also a big plus.

Where to buy: $499 / $599 at (without/with Flow Cable)


Headphoneus Supremus
Apos Caspian: An International Effort Brings Cooperation To Sound
Pros: Cooperation brings good things
Richness, the flavor I like
Decently deep reach
Smooth sounding, which is not bad
Good looking unit
Get the Flow cable as well
Cons: Sound signature not for everyone
Lacks overall coherence
Lacks finer details
Could be more vibrant overall
Apos Caspian ($499): An International Effort Brings Cooperation To Sound


Apos Caspian

As part of the continuing efforts from @Barra and AudioTiers, the Apos was sent as a review sample. Once done, the unit will be sent to another reviewer as part of an agreement with AudioTiers. What follows are my words, and my words alone. The unit is on loan, so care will be given to the unit then sent along to the next lucky participant.

More: The Apos Caspian is a conglomeration between Sandu Vitalie of, Apos and Valentin Kazanzhi of Kennerton fame. The driver is Kennerton’s, using a custom 50mm graphene-coated composite dynamic drivers that are mechanically decoupled from the wooden housing. The cups are Oak and remind me of my Rognir in Bog Oak. Future models according to Vitalie may come in a variety of wood cup choices, much like Kennerton models. A fully open back headphone, using 3-pin mini-XLR connections were of his choosing as well. The total package is marketed as usable for your desktop prime system and your portable dongle/Smartphone system as well. As such, I will test this across many platforms as well as relying upon Vitalie’s review for the technical aspects.

I have included a variety of open and closed back headphones in this review as I feel the price point warrants this. Plus, I am in the process of culling my herd and the Mr. Speakers Aeon Flow Open has left my stable...

  • Driver: Graphene-coated multilayered composite
  • Driver unit: 50mm
  • Frequency response: 5-45,000Hz
  • Sensitivity: 115dB
  • Impedance: 33Ω
  • Maximum input power: 500mW
  • Ear cup outer material: Natural sheepskin leather
  • Ear cup inner material: Acoustic memory foam
  • Thickness of pads: 1” (27mm)
  • External dimensions of pads: 4.5” x 3.4” (115mm x 88mm)
  • Height and width of ear pad opening: 3” x 1.7” (77mm x 45mm)
  • Grille material: aluminum alloy
  • Headband materials: stainless steel, natural leather outer lining, bio-leather inner lining, polyurethane foam insert
  • Yoke material: stainless steel
  • Weight: 13.3oz (378g)

In The Box:
  • Apos Caspian headphone
  • Leather carrying bag
  • Stock headphone cable (single-ended 6.35mm termination)
  • *Apos Flow mini-XLR to XLR cable included as well

Gear Compared/Used:

Sivga Phoenix ($255)
Sendy Aiva ($599)
Thinksound ov21 ($349)
Final Audio Sonorous III ($399)

MacBook Pro/XDuoo XA-10
Shanling Audio M6 Pro
iPhone 13 Pro Max/EarMen Sparrow
MacBook Pro/iFi Pro iDSD/iCAN


Reckoner, Avalon-Peter Frampton
Lazeez-Acoustic Alchemy
Shake-Jesse Cook
The Peppery Man-Natalie Merchant
Number 5-Jesse Cook
Lewis & Clark-Tommy Emmanuel
Guitar Boogie-Tommy Emmanuel
Hotel California-The Eagles
Smash Up On Highway One-Brian Setzer
Evil Ways-Santana


Following Kennerton’s model, the box is subdued cardboard but of dark green with more verbiage on the faces as well. The back lists the virtues of what is handmade and some of the features such as driver size (and make) along with the nature of the aluminum grille.

The inner sleeve (like Kennerton again) carries much information including the reasoning, name, sound, & look of the Caspian. I do appreciate this aspect from company’s so that one learns much of the reasoning, though and passion behind the ware. Using sustainable practices and the ability for longevity also lies at the heart of the headphone, and Apos espouses the use of non-endangered wood for the cups and longevity of stainless steel (non-rusting). All aspects of the headphone speak of quality and good thought from Apos.

The eco-leather case is one of typical Kennerton again. One of slightly oversized zippered “purse,” with a good-sized top section where the cable and/or adaptor can be kept. Sliding the headphone into the open cavern is of easy affair and you need not “close down” the headphone, thus losing your adjustment like many headphones and cases. This provides less wear and tear to the adjusting mechanism as well. A shoulder strap also allows the user to carry the headphone like a shoulder bag. There is enough room for your DAP or Dongle as you may, thus making the whole case at least semi-portable.



The Caspian is of sturdy build without being hefty. Not as large a unit as Kennerton models, the Apos is an over ear matching closely the size of the Sendy Aiva and Thinksound ov21. The dark Oak looks stunning and reminds me of the Bog Oak on my Rögnir. Since I am the second user after Bill, the unit does show a few marks on the sliders, which could be due to a thinner powder coating. There is a slight rotational aspect to the slider inside the housing, which gives a decent fore/aft movement on my head.

The yoke is thin stainless steel, with divets used as adjusting points, which go into the headband. There is good give to the headband, which affords solid fit on many sizes of heads, and with a good grip. I did not find too much pressure to the fit as the soft native leather pads are quite giving. Almost like memory foam, the pads conform to the shape of your head nicely. Add in good padding to the underside of the headband and you have a good fit. A mix of plastic, stainless steel and wood makes for a good-looking unit, even if the finish/build is not perfect. It seems the plastic covers over the yoke slot do not match perfectly but do snap together (and have two screws) for a good fit.

A large black grill with the “A” logo graces each side, making the Oak cups seem smaller. This is the result of having an open back design; you don’t have much surrounding the grill. That said, the dark Oak looks quite nice adding to the black grill. The oval shaped cups complimenting the round grill nicely. The pads have the typical lip, which slides into the slot keeping the pads in place. They can somewhat easily rotate within that slot, allowing another fine-tuning adjustment.

The included cable follows Kennerton’s route as well as it is thick and covered in braided material. The stock cable comes with mini-XLR and a 6.35mm jack, of good build and length. It does curl a good bit, a factor of being wound fairly tightly. I would imagine over time it would lay better. Little to no microphonics are had as well.

If you were to hand the Caspian to someone and ask the price of the unit, you would most likely get the price listed above due to the elegant look and quality materials. I would not disagree with this assessment.



Using a Kennerton-derived 50mm composite graphene driver, the Caspian is detached from the housing, thus reducing vibrations. The thin membrane makes for quick reactions to voltage swings, and thus is easy to drive across different sources. Graphene is stronger than steel, and with that quick moving membrane can deliver very quick sounds as well as shorter decay making it move very efficiently with the magnets.

The voice coil is lightweight aluminum (CCAW) covered with a thin layer of copper increasing conductivity as well. Combine this with a powerful magnet, and you have a highly efficient driver unit that is also easy to drive. Sensitivity is quite high for something of this nature at 115dB per 1mW of power making what might be construed as something where background noise could possibly permeate the sound, but we shall see.



As an open back one would expect a wide soundstage and good air between notes. This is mostly true, but the sound lies on the warmer side of life, just. There is a certain naturalness to the sound, which can come across as muddling to some, but I chalk this up as just the signature of a certain amount of richness. This is certainly not neutral, nor is it analytical either.

Bass comes on when needed and is source dependent to me as through the XDuoo XA-10, which is analytically neutral bass is short but not thin. A rich crispness pervades my senses on Lazeez from Acoustic Alchemy with this set up, which is not bad. The mids comes across as organic and natural as well, with a somewhat (to me) rolled off treble. There is a bit of a spike, but not enough to bother me and enough to emphasize the upper reaches of the sound signature. There also seems to be an intimacy to the signature, which some might construe as veiled. I may not call it that, but this adds to the warmth of the signature.



A certain richness pervades the bass region of sound as evidenced on Tommy Emmanuel’s Lewis & Clark; which is a fantastic acoustic guitar song to use as a gauge. Not deep reaching by any means, but there when needed and of sufficient quality to hold down the line. There is little bleed into the mids as a result. There is that richness, which seems to meld the lower mids to the bass qualities nicely. Upon listening to the Rögnir, there was a wonderful synergy of organic naturalness to the sound, which just brought out the emotion of whatever I listened to. That is somewhat present in the Caspian and one can easily hear the “family” resemblance. But they are indeed not the same.

Those emotive responses of the mids come across as organic in sound, but not the most realistic. There is definitely warmth and richness here, but this seems to be at the expense of a clarity-driven mid sound to me. The Eagles live version of Hotel California comes across as passionate, but almost flat to me. I get the warmth, but to me there seems to be too much and at the expense of detail. An example of that would be Brian Setzer’s Smash Up On Highway One, a thoroughly vibrant, engaging song. On the Caspian it lacks that vibrant tonality, which to me is what makes the song fabulous and the want to raise the volume. Not so with the Caspian.

Cymbal hits and upper end notes in the treble region come across as leaving me wanting better clarity and definition. Mind you there is plenty of the emotive response here, but again at the downfall of clarity. I do enjoy the sound up top, but even I wish for better definition and a certain amount of push up top compared to some.

There is no denying that the soundstage is that of an open back headphone. Coming across as decently wide (but not cavernous), along with good depth and height to match, there is good air to the definition of layering & separation. Adele’s Easy On Me comes across with a passionate plea of a sound, but lacks true depth to me. It is good but lacks that visceral experience I expect when listening to Adele. I Drink Wine comes across as a soulsy song, with good reach and a beat to it, which makes one tap their feet as she sings that soul searching song. Good stuff.


Apos Flow XLR balanced ($159): I found this pairing the best, especially when paired with my iFi Pro duo listed above. To me this changed the whole character. The iFi products are known as rich and full of warmth. Adding the Apos balanced cable makes for one fine set up. To me, this opened the mids up nicely, losing that “veiled” characteristic of which I speak. There is even an extra bit of sparkle up top. If this were my headphone, the Apos Flow would be a no-brainer addition to the case; especially at the price. Yes, much of this character change has to do with the ifi DAC/Amp in which it is fed from, but the Apos duo makes for a very good pairing.

iPhone 13 Pro Max/EarMen Eagle: Keeping with the semi-affordable price with the Eagle, this trio shows the Caspian can indeed be used with a Smartphone and dongle. Coming across with a bit more crispness to the sound due to the Eagle, the Caspian provided another example of what a solid sound source can do for the unit. This would be quite an acceptable trio to me.

MacBook Pro/XDuoo XA-10: XDuoo has produced some knockout items from the X10Tii transport to the TA-30 immensely powered tube amplifier. The XA-10 is another hit, but on the digital front. Cleanly running to a fault, this was not the best combination as witnessed by the other remarks here. I did appreciate the sound, but when paired, the Caspian came across as somewhat dry and veiled in the mid-section. Based upon my evidence with the other sources, this is probably the XA-10 in the chain. I am by no means saying the XA-10 is not good for it is, but not the best pairing here.



Apos Caspian ($499) v Sivga Phoenix ($255):

The Phoenix represents Sivga’s foray into the affordable open back market and follows the success of the Sendy Aiva (see below). At half the price, the Phoenix is stunning in looks, but many thought it had a “fake” aura to it, which seemed industrial. For the price and whom Sivga was aiming for, the Phoenix met all comers head on. And did well in my book along with others. Not as rich in tonality as the Caspian and with more forward mids, the Phoenix sounds more open. It has better clarity to me, but the two are oriented towards differing tastes. Detail retrieval is about the same, and the Phoenix has a bit deeper reach of bass; with better control as well. The Caspian comes across with more rumble but is less controlled. The Caspian does come across as thicker in sound, and with more naturalness, but clarity goes to the Phoenix.

Apos Caspian ($499) v Sendy Aiva ($599):

A much more detailed unit than the Phoenix, I fell for the Aiva at first look. And after listening I still appreciated the sound emanating from within. Coming with a 4.4bal cable and adapter the Aiva is a multi-use open back headphone. With much more of the bling looks than the Caspian, the sound comes across as a direct competitor. Sendy/Sivga seem to have a love/hate with no between relationship among many reviewers. Count me among those who really appreciate the sound along with the gorgeous looks as well.

Warmer and richer, much like the Caspian, the Aiva reaches deeper and with better control as well down low. Mids are slightly behind the rest, and a bit thin when compared to the Caspian, though. Much the same treatment up top as the Caspian, the Aiva sounds sumptuous in presentation, especially with the balanced option and a less veiled sound as well. But the Caspian comes across as natural and sumptuous as well. So, this comes down to looks and a fit, which is slightly better on the Caspian.

Apos Caspian ($499) v Thinksound ov21 ($349):

I am a fan of Thinksound. Period. So, when the ov21 went up on Kickstarter, I jumped. Used to the fine, deep reaching bass of the on2, and an absolutely fun sound, I anticipated the same from the ov21, much like the in20 has. But the ov21 comes across as a much more refined version of the house sound, without the deep reaching bass normally had. While I am a bit disappointed in that aspect, one cannot deny that there is much better clarity on the ov21 than the previous models. This is not a bad unit for their first closed back headphone, and when you throw in the use of reclaimed materials and Eastman’s expertise in making the wood for the faceplate you still have a winner in my book.

But if we talk about sound, the Caspian wins. More natural in sound, and with that bit of rumble, the Apos comes across with a more emotive response. But the ov21 is still a very fine unit in my opinion.

Apos Caspian ($499) v Final Audio Sonorous III ($399):

The Final Sonorous VIII is known to be one of the best closed back headphones out there. Coming across the III secondhand, I took a plunge and do not regret it. Providing excellent clarity and detail, the Sonorous III is an underappreciated gem to me. Atypical shape makes it hard to find a decent case, though. Providing good reach down low, with airy, sumptuous mids, the Sonorous III give way to excellent detail up top as well. To me it has better treatment up top than the Caspian but does lack a bit in the musicality or rich naturalness to the Caspian. It is something I can live with though, for the rest of it is quite good. The Caspian falls behind the Sonorous III to me in presentation as the III comes across as quite accurate as well. A good choice at this price for a closed back in my estimation.



When someone cares enough about their hobby to make an impression by making their interpretation of what a good headphone should sound like, I appreciate it. I really do. The time and effort needed to do this, let alone get other company’s on board is a huge undertaking. Throw in all of the models and prototypes and meeting and such; and you get a massive investment from the start. This takes guts. And money. And commitment. I applaud this all around. But the downside is that the product produced will have the flavors chosen by the inventor. That can certainly be good and bad. Here with the Apos Caspian it is mostly good.

The looks are subdued and gorgeous. The build quality mimics those of one of the major investors, Kennerton. And that is a good thing in my book. Entering the insanely tough sub-$750 headphone market is a tall task and one in which all three parties took seriously. Throw on the Apos Flow cable, and you hit right at the $750 price, which makes this one in which to consider in my humble opinion.

I applaud Mr. Vitalie, Apos & Kennerton for the conglomerate mixing to produce the Caspian. It indeed takes guts to follow through with a dream such as this. While the Caspian may not suit all of my tastes, it is a pretty decent headphone, nonetheless. As stated above, pair it with the Apos Flow and you have a pretty nice set up. I finish this by listening to Lenny from Stevie Ray Vaughan, and that is all right in my book.

I again thank @Barra and Apos for the loan of the Caspian. The next lucky participant will be in for a decent treat.




500+ Head-Fier
nice design any chance they will do other colors like black wood or red?
I personally doubt it, at least for now. Anything is possible in the future (imo).

Try reaching out to them. Since Kennerton makes them, they might be open to a special private order (and I'd assume it would be at a special private price).