Apos Caspian ($499):An International Effort Brings Cooperation To Sound

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

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 Soundnews.net, 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.


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